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# Æthelberht of Kent
## Trade and coinage {#trade_and_coinage}
There is little documentary evidence about the nature of trade in Æthelberht\'s Kent. It is known that the kings of Kent had established royal control of trade by the late seventh century, but it is not known how early this control began. There is archaeological evidence suggesting that the royal influence predates any of the written sources. It has been suggested that one of Æthelberht\'s achievements was to take control of trade away from the aristocracy and to make it a royal monopoly. The continental trade provided Kent access to luxury goods which gave it an advantage in trading with the other Anglo-Saxon nations, and the revenue from trade was important in itself.
Kentish manufacture before 600 included glass beakers and jewelry. Kentish jewellers were highly skilled, and before the end of the sixth century they gained access to gold. Goods from Kent are found in cemeteries across the channel and as far away as at the mouth of the Loire. It is not known what Kent traded for all of this wealth, although it seems likely that there was a flourishing slave trade. It may well be that this wealth was the foundation of Æthelberht\'s strength, although his overlordship and the associated right to demand tribute would have brought wealth in its turn.
It may have been during Æthelberht\'s reign that the first coins were minted in England since the departure of the Romans: none bear his name, but it is thought likely that the first coins predate the end of the sixth century. These early coins were gold, and probably were the shillings (*scillingas* in Old English) that are mentioned in Æthelberht\'s laws. The coins are also known to numismatists as *thrymsas*.
## Death and succession {#death_and_succession}
Æthelberht died on 24 February 616 and was succeeded by his son, Eadbald, who was not a Christian---Bede says he had been converted but went back to his pagan faith, although he ultimately did become a Christian king. Eadbald outraged the church by marrying his stepmother, which was contrary to Church law, and by refusing to accept baptism. Sæberht of the East Saxons also died at approximately this time, and he was succeeded by his three sons, none of whom were Christian. A subsequent revolt against Christianity and the expulsion of the missionaries from Kent may have been a reaction to Kentish overlordship after Æthelberht\'s death as much as a pagan opposition to Christianity.
In addition to Eadbald, it is possible that Æthelberht had another son, Æthelwald. The evidence for this is a papal letter to Justus, archbishop of Canterbury from 619 to 625, that refers to a king named Aduluald, who is apparently different from Audubald, which refers to Eadbald. There is no agreement among modern scholars on how to interpret this: \"Aduluald\" might be intended as a representation of \"Æthelwald\", and hence an indication of another king, perhaps a sub-king of west Kent; or it may be merely a scribal error which should be read as referring to Eadbald.
## Liturgical celebration {#liturgical_celebration}
Æthelberht was later regarded as a saint for his role in establishing Christianity among the Anglo-Saxons. His feast day was originally 24 February but was changed to 25 February. In the 2004 edition of the Roman Martyrology, he is listed under his date of death, 24 February, with the citation: \'King of Kent, converted by St Augustine, bishop, the first leader of the English people to do so\'. The Roman Catholic Archdiocese of Southwark, which contains Kent, commemorates him on 25 February.
He is also venerated in the Eastern Orthodox Church as **Saint Ethelbert, king** **of Kent**, his day commemorated on 25 February
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# EasyWriter
**EasyWriter** was the first word processor for the Apple II. It was written by John Draper and released in 1979.
## History
Published by Information Unlimited Software (IUS),`{{r|freibergerius19820823}}`{=mediawiki} it was written by John Draper\'s Cap\'n Software, which also produced a version of Forth, which EasyWriter was developed in. Draper developed EasyWriter while serving nights in the Alameda County Jail under a work furlough program.
It was later ported to the IBM PC and released with the new computer in August 1981 as a launch title. Many criticized EasyWriter 1.0, distributed by IBM, for being buggy and hard to use;`{{r|shuford198305}}`{=mediawiki} *PC Magazine* told the company as early as December 1981 that subscribers \"wish IBM had provided better word processing\". The company quickly persuaded IUS to develop a new version. (When founder William Baker later sent \"I Survived EasyWriter\" T-shirts, IBM returned them stating that it did not accept gifts.) IBM offered a free upgrade to version 1.10 to version 1.0 owners,`{{r|fluegelman198208}}`{=mediawiki} but EasyWriter\'s poor quality had caused others to quickly provide alternatives, such as Camilo Wilson\'s Volkswriter.`{{r|fluegelman198208}}`{=mediawiki}
IUS released a separate application, EasyWriter II. Completely rewritten by Basic Software Group,`{{r|shuford198305}}`{=mediawiki} IUS described it as a more \"professional\" word processor.`{{r|fluegelman198208}}`{=mediawiki} The company emphasized that II---developed with C instead of Forth---\"is not an updated version of the original IBM selection or its upgrade\".
## Reception
*BYTE* in 1981 reviewed EasyWriter and EasyWriter Professional for the Apple II, stating that \"editing is a pleasure with either version\", and approving of their features, user interface, and documentation. In an early review of the IBM PC, however, the magazine in 1982 stated that EasyWriter for it or the Apple II \"didn\'t seem to be of the same caliber as, say, VisiCalc or the Peachtree business packages\", citing the lack of ease of use and slow scrolling as flaws, and advised those who planned to use the IBM PC primarily for word processing to buy another computer until alternative software became available. Andrew Fluegelman wrote in *PC Magazine* that year that although EasyWriter 1.0 appeared to be an easy-to-use word processor for casual users, it \"contains a few very annoying inconveniences and some very serious traps\". He cited several bugs, slow performance, and user-interface issues, and later called it \"pretty much a lemon\". Fluegelman said in 1985 that the review had become notorious, as he was a novice computer user and \"no one knew who I was, I didn\'t know anybody, I just took this program and I said \'This is terrible\'\", but \"it deserved panning\".
IBM\'s Don Estridge admitted in 1983 that he \"tried to use EasyWriter 1.0 and had the same experience everybody else had\". EasyWriter 1.10 resolved most of Fluegelman\'s complaints. He reported that it \"performs smoothly, will handle most any routine writing and printing job, and is easy to learn and operate\", and that if IBM had released 1.10 first EasyWriter would likely have become the standard PC word processor.
*BYTE* criticized EasyWriter II for running as a booter instead of using DOS, requiring specially formatted disks for storage and a utility to convert to DOS-formatted disks, not being compatible with double-sided drives, and using a heavily modal editing interface
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# Nitrox
**Nitrox** refers to any gas mixture composed (excepting trace gases) of nitrogen and oxygen. It is usually used for mixtures that contain less than 78% nitrogen by volume. In the usual application, underwater diving, nitrox is normally distinguished from air and handled differently. The most common use of nitrox mixtures containing oxygen in higher proportions than atmospheric air is in scuba diving, where the reduced partial pressure of nitrogen is advantageous in reducing nitrogen uptake in the body\'s tissues, thereby extending the practicable underwater dive time by reducing the decompression requirement, or reducing the risk of decompression sickness (also known as *the bends*). The two most common recreational diving nitrox mixes are 32% and 36% oxygen, which have maximum operating depths of about 110 feet (34 meters) and 95 feet (29 meters) respectively.
Nitrox is used to a lesser extent in surface-supplied diving, as these advantages are reduced by the more complex logistical requirements for nitrox compared to the use of simple low-pressure compressors for breathing gas supply. Nitrox can also be used in hyperbaric treatment of decompression illness, usually at pressures where pure oxygen would be hazardous. Nitrox is not a safer gas than compressed air in all respects; although its use can reduce the risk of decompression sickness, it increases the risks of oxygen toxicity and fire.
Though not generally referred to as nitrox, an oxygen-enriched air mixture is routinely provided at normal surface ambient pressure as oxygen therapy to patients with compromised respiration and circulation.
## Physiological effects under pressure {#physiological_effects_under_pressure}
### Decompression benefits {#decompression_benefits}
Reducing the proportion of nitrogen by increasing the proportion of oxygen reduces the risk of decompression sickness for the same dive profile, or allows extended dive times without increasing the need for decompression stops for the same risk. The significant aspect of extended no-stop time when using nitrox mixtures is reduced risk in a situation where breathing gas supply is compromised, as the diver can make a direct ascent to the surface with an acceptably low risk of decompression sickness. The exact values of the extended no-stop times vary depending on the decompression model used to derive the tables, but as an approximation, it is based on the partial pressure of nitrogen at the dive depth. This principle can be used to calculate an equivalent air depth (EAD) with the same partial pressure of nitrogen as the mix to be used, and this depth is less than the actual dive depth for oxygen enriched mixtures. The equivalent air depth is used with air decompression tables to calculate decompression obligation and no-stop times. The Goldman decompression model predicts a significant risk reduction by using nitrox (more so than the PADI tables suggest).
### Nitrogen narcosis {#nitrogen_narcosis}
Controlled tests have not shown breathing nitrox to reduce the effects of nitrogen narcosis, as oxygen seems to have similarly narcotic properties under pressure to nitrogen; thus one should not expect a reduction in narcotic effects due only to the use of nitrox. Nonetheless, there are people in the diving community who insist that they feel reduced narcotic effects at depths breathing nitrox. This may be due to a dissociation of the subjective and behavioural effects of narcosis. Although oxygen appears chemically more narcotic at the surface, relative narcotic effects at depth have never been studied in detail, but it is known that different gases produce different narcotic effects as depth increases. Helium has no narcotic effect, but results in HPNS when breathed at high pressures, which does not happen with gases that have greater narcotic potency. However, because of risks associated with oxygen toxicity, divers do not usually use nitrox at greater depths where more pronounced narcosis symptoms are more likely to occur. For deep diving, trimix or heliox gases are typically used; these gases contain helium to reduce the amount of narcotic gases in the mixture.
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# Nitrox
## Physiological effects under pressure {#physiological_effects_under_pressure}
### Oxygen toxicity {#oxygen_toxicity}
Diving with and handling nitrox raise a number of potentially fatal dangers due to the high partial pressure of oxygen (ppO~2~). Nitrox is not a deep-diving gas mixture owing to the increased proportion of oxygen, which becomes toxic when breathed at high pressure. For example, the maximum operating depth of nitrox with 36% oxygen, a popular recreational diving mix, is 29 m to ensure a maximum ppO~2~ of no more than 1.4 bar. The exact value of the maximum allowed ppO~2~ and maximum operating depth varies depending on factors such as the training agency, the type of dive, the breathing equipment and the level of surface support, with professional divers sometimes being allowed to breathe higher ppO~2~ than those recommended to recreational divers.
To dive safely with nitrox, the diver must learn good buoyancy control, a vital part of scuba diving in its own right, and a disciplined approach to preparing, planning and executing a dive to ensure that the ppO~2~ is known, and the maximum operating depth is not exceeded. Many dive shops, dive operators, and gas blenders (individuals trained to blend gases) require the diver to present a nitrox certification card before selling nitrox to divers.Additionally, it is strongly encouraged for divers to confirm the percentage of oxygen in their tank before every dive, regardless of the specified amount on their tank. This is done by expelling a small amount of air from the diver\'s tank into an oxygen analyzer. This is to further limit the possibility of oxygen toxicity due to errors in previous testing.
Some training agencies, such as PADI and Technical Diving International, teach the use of two depth limits to protect against oxygen toxicity. The shallower depth is called the \"maximum operating depth\" and is reached when the partial pressure of oxygen in the breathing gas reaches 1.4 bar. The deeper depth, called the \"contingency depth\", is reached when the partial pressure reaches 1.6 bar. Diving at or beyond this level exposes the diver to a greater risk of central nervous system (CNS) oxygen toxicity. This can be extremely dangerous since its onset is often without warning and can lead to drowning, as the regulator may be spat out during convulsions, which occur in conjunction with sudden unconsciousness (general seizure induced by oxygen toxicity).
Divers trained to use nitrox may memorise the acronym VENTID-C or sometimes ConVENTID, (which stands for **V**ision (blurriness), **E**ars (ringing sound), **N**ausea, **T**witching, **I**rritability, **D**izziness, and **C**onvulsions). However, evidence from non-fatal oxygen convulsions indicates that most convulsions are not preceded by any warning symptoms at all. Further, many of the suggested warning signs are also symptoms of nitrogen narcosis, and so may lead to misdiagnosis by a diver. A solution to either is to ascend to a shallower depth.
### Carbon dioxide retention {#carbon_dioxide_retention}
Use of nitrox may cause a reduced ventilatory response, and when breathing dense gas at the deeper limits of the usable range, this may result in carbon dioxide retention when exercise levels are high, with an increased risk of loss of consciousness.
### Other effects {#other_effects}
There is anecdotal evidence that the use of nitrox reduces post-dive fatigue, particularly in older and or obese divers; however a double-blind study to test this found no statistically significant reduction in reported fatigue. There was, however, some suggestion that post-dive fatigue is due to sub-clinical decompression sickness (DCS) (i.e. micro bubbles in the blood insufficient to cause symptoms of DCS); the fact that the study mentioned was conducted in a dry chamber with an ideal decompression profile may have been sufficient to reduce sub-clinical DCS and prevent fatigue in both nitrox and air divers. In 2008, a study was published using wet divers at the same depth no statistically significant reduction in reported fatigue was seen.
Further studies with a number of different dive profiles, and also different levels of exertion, would be necessary to fully investigate this issue. For example, there is much better scientific evidence that breathing high-oxygen gases increases exercise tolerance, during aerobic exertion. Though even moderate exertion while breathing from the regulator is a relatively uncommon occurrence in recreational scuba, as divers usually try to minimize it in order to conserve gas, episodes of exertion while regulator-breathing do occasionally occur in recreational diving. Examples are surface-swimming a distance to a boat or beach after surfacing, where residual \"safety\" cylinder gas is often used freely, since the remainder will be wasted anyway when the dive is completed, and unplanned contingencies due to currents or buoyancy problems. It is possible that these so-far un-studied situations have contributed to some of the positive reputation of nitrox.
A 2010 study using critical flicker fusion frequency and perceived fatigue criteria found that diver alertness after a dive on nitrox was significantly better than after an air dive.
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# Nitrox
## Uses
### Underwater diving {#underwater_diving}
Enriched Air Nitrox`{{r|EANx}}`{=mediawiki}, nitrox with an oxygen content above 21%, is mainly used in scuba diving to reduce the proportion of nitrogen in the breathing gas mixture. The main benefit is reduced decompression risk. To a considerably lesser extent it is also used in surface supplied diving, where the logistics are relatively complex, similar to the use of other diving gas mixtures like heliox and trimix.
#### Training and certification {#training_and_certification}
(Nitrox diver) allows the diver to use a single nitrox gas mixture with 40% or less oxygen by volume on a dive without obligatory decompression. The reason for using nitrox on this type of dive profile can be to extend the no-decompression limit, and for shorter dives, to reduce the decompression stress. The course is short, with a theory module on the risks of oxygen toxicity and the calculation of maximum operating depth, and a practical module of generally two dives using nitrox. It is one of the most popular further training programmes for entry level divers as it makes longer dives possible at a large number of popular sites. Gases suitable for this application may be referred to as recreational nitrox.
Advanced nitrox certification (`{{visible anchor|Advanced nitrox diver}}`{=mediawiki}) requires competence to carry two nitrox mixtures in separate scuba sets, and to use the richer mix for accelerated decompression at the end of the dive, switching gases underwater at the correct planned depth and selecting the new gas on the dive computer if one is carried. For the purposes of the certification any mixture from air to nominally 100% oxygen may be used, though at least one agency prefers to limit oxygen fraction to 80% as they consider this has a lower risk for acute oxygen toxicity.
### Therapeutic recompression {#therapeutic_recompression}
Nitrox50 is used as one of the options in the first stages of therapeutic recompression using the Comex therapeutic table CX 30 for treatment of vestibular or general decompression sickness. Nitrox is breathed at 30 msw and 24 msw and the ascents from these depths to the next stop. At 18 m the gas is switched to oxygen for the rest of the treatment.
### Medicine, mountaineering and unpressurised aircraft {#medicine_mountaineering_and_unpressurised_aircraft}
The use of oxygen at high altitudes or as oxygen therapy may be as supplementary oxygen, added to the inspired air, which would technically be a use of nitrox, blended on site, but this is not normally referred to as such, as the gas provided for the purpose is oxygen.
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# Nitrox
## Terminology
Nitrox is known by many names: Enriched Air Nitrox, Oxygen Enriched Air, Nitrox, EANx or Safe Air. Since the word is a compound contraction or coined word and not an acronym, it should not be written in all upper case characters as \"NITROX\", but may be initially capitalized when referring to specific mixtures such as Nitrox32, which contains 68% nitrogen and 32% oxygen. When one figure is stated, it refers to the oxygen percentage, not the nitrogen percentage. The original convention, Nitrox68/32 became shortened as the first figure is redundant.
The term \"nitrox\" was originally used to refer to the breathing gas in a seafloor habitat where the oxygen has to be kept to a lower fraction than in air to avoid long term oxygen toxicity problems. It was later used by Dr Morgan Wells of NOAA for mixtures with an oxygen fraction higher than air, and has become a generic term for binary mixtures of nitrogen and oxygen with any oxygen fraction, and in the context of recreational and technical diving, now usually refers to a mixture of nitrogen and oxygen with more than 21% oxygen. \"Enriched Air Nitrox\" or \"EAN\", and \"Oxygen Enriched Air\" are used to emphasize richer than air mixtures. In \"EANx\", the \"x\" was originally the x of nitrox, but has come to indicate the percentage of oxygen in the mix and is replaced by a number when the percentage is known; for example, a 40% oxygen mix is called EAN40. The two most popular blends are EAN32 and EAN36, developed by NOAA for scientific diving, and also named Nitrox I and Nitrox II, respectively, or Nitrox68/32 and Nitrox64/36. These two mixtures were first utilized to the depth and oxygen limits for scientific diving designated by NOAA at the time.
The term Oxygen Enriched Air (OEN) was accepted by the (American) scientific diving community, but although it is probably the most unambiguous and simply descriptive term yet proposed, it was resisted by the recreational diving community, sometimes in favour of less appropriate terminology.
In its early days of introduction to non-technical divers, nitrox has occasionally also been known by detractors by less complimentary terms, such as \"devil gas\" or \"voodoo gas\" (a term now sometimes used with pride).
American Nitrox Divers International (ANDI) uses the term \"SafeAir\", which they define as any oxygen-enriched air mixture with O~2~ concentrations between 22% and 50% that meet their gas quality and handling specifications, and specifically claim that these mixtures are safer than normally produced breathing air for the end user not envolved to the mix production which.`{{clarify|typo or grammar error garbage|date=January 2022}}`{=mediawiki} Considering the complexities and hazards of mixing, handling, analyzing, and using oxygen-enriched air, this name is considered inappropriate by those who consider that it is not inherently \"safe\", but merely has decompression advantages.
### MOD
Maximum Operating Depth (MOD) is the maximum safe depth at which a given nitrox mixture can be used. MOD depends on the allowed partial pressure of oxygen, which is related to exposure time and the acceptable risk assumed for central nervous system oxygen toxicity. Acceptable maximum ppO~2~ varies depending on the application:
- 1.2 is often used in closed circuit rebreathers.
- 1.4 is recommended by several recreational training agencies for ordinary scuba diving.
- 1.5 is allowed for commercial diving in some jurisdictions.
- 1.6 is allowed for technical diving decompression stops, and is the recommended maximum according to NOAA
Higher values are used by commercial and military divers in special circumstances, often when the diver uses surface supplied breathing apparatus, or for treatment in a chamber, where the airway is relatively secure.
## Equipment
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# Nitrox
## Choice of mixture {#choice_of_mixture}
The two most common recreational diving nitrox mixes contain 32% and 36% oxygen, which have maximum operating depths (MODs) of 34 m and 29 m respectively when limited to a maximum partial pressure of oxygen of 1.4 bar. Divers may calculate an equivalent air depth to determine their decompression requirements or may use nitrox tables or a nitrox-capable dive computer.
Nitrox with more than 40% oxygen is uncommon within recreational diving. There are two main reasons for this: the first is that all pieces of diving equipment that come into contact with mixes containing higher proportions of oxygen, particularly at high pressure, need special cleaning and servicing to reduce the risk of fire. The second reason is that richer mixes extend the time the diver can stay underwater without needing decompression stops far further than the duration permitted by the capacity of typical diving cylinders. For example, based on the PADI nitrox recommendations, the maximum operating depth for EAN45 would be 21 m and the maximum dive time available at this depth even with EAN36 is nearly 1 hour 15 minutes: a diver with a breathing rate of 20 litres per minute using twin 10-litre, 230-bar (about double 85 cu. ft.) cylinders would have completely emptied the cylinders after 1 hour 14 minutes at this depth.
Use of nitrox mixtures containing 50% to 80% oxygen is common in technical diving as decompression gas, which by virtue of its lower partial pressure of inert gases such as nitrogen and helium, allows for more efficient (faster) elimination of these gases from the tissues than leaner oxygen mixtures.
In deep open circuit technical diving, where hypoxic gases are breathed during the bottom portion of the dive, a Nitrox mix with 50% or less oxygen called a \"travel mix\" is sometimes breathed during the beginning of the descent in order to avoid hypoxia. Normally, however, the most oxygen-lean of the diver\'s decompression gases would be used for this purpose, since descent time spent reaching a depth where bottom mix is no longer hypoxic is normally small, and the distance between this depth and the MOD of any nitrox decompression gas is likely to be very short, if it occurs at all.
### Best mix {#best_mix}
The composition of a nitrox mix can be optimized for a given planned dive profile. This is termed \"Best mix\", for the dive, and provides the maximum no-decompression time compatible with acceptable oxygen exposure. An acceptable maximum partial pressure of oxygen is selected based on depth and planned bottom time, and this value is used to calculate the oxygen content of the best mix for the dive:
$$f_{\text{O}_2,\text{max}} = \frac{p_{\text{O}_2,\text{max}}}{p} = \frac{\text{Maximum acceptable partial pressure of oxygen}}{\text{Maximum ambient pressure of the dive}}$$
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# Nitrox
## Production
There are several methods of production:
- Mixing by partial pressure: a measured pressure of oxygen is decanted into the cylinder and cylinder is \"topped up\" with air from the diving air compressor. This method is very versatile and requires relatively little additional equipment if a suitable compressor is available, but it is labour-intensive, and high partial pressures of oxygen are relatively hazardous.
- Pre-mix decanting: the gas supplier provides large cylinders with popular mixes such as 32% and 36%. These may be further diluted with air to provide a larger range of mixtures.
- Mixing by continuous blending: measured quantities of oxygen are introduced to air and mixed with it before it reaches the compressor inlet. Concentration of oxygen is commonly monitored as partial pressure using an oxygen cell. The compressor and particularly the compressor oil, must be suitable for this service. If the resulting oxygen fraction is less than 40%, the cylinder and valve may not be required to be cleaned for oxygen service. Relatively efficient and quick compared to partial pressure blending, but requires a suitable compressor, and the range of mixes may be limited by the compressor specification.
- Mixing by mass fraction: oxygen and air or nitrogen are added to a cylinder that is accurately weighed until the required mix is achieved. This method requires fairly large and highly accurate scales, otherwise it is similar to partial pressure blending, but insensitive to temperature variations.
- Mixing by gas separation: a nitrogen permeable membrane is used to remove some of the nitrogen molecules from air until the required mix is achieved. The resulting low pressure nitrox is then pumped into cylinders by a compressor.\
A limited range of mixes is possible, but the equipment is quick and easy to operate and relatively safe, as there is never high partial pressure oxygen involved. A supply of clean low-pressure air at a constant temperature is required for consistent results. This may be supplied from a low pressure compressor or a regulated supply from high-pressure storage or compressor. The air must be free of contaminants that could clog the membrane, and at a constant inlet temperature and pressure to produce a consistent delivered partial pressure of oxygen. The air must be of breathing quality, other contaminants must be filtered out independently. The input air pressure is regulated and pressure over the membrane controlled to adjust the product oxygen fraction. CGA Grade D or E air quality is suitable for supply gas, and is commonly heated to a constant inlet temperature. Heating also reduces the chance of high humidity causing wetting of the membrane. In a typical system supply air enters the thousands of hollow fibres of the membrane at one end, and oxygen preferentially permeates the fibre walls, leaving mostly nitrogen at the discharge end, which is vented from the system as waste.
- Pressure swing adsorption requires relatively complex equipment, otherwise the advantages are similar to membrane separation. PSA is a technology used to separate gases from a mixture under pressure according to the molecular characteristics and affinity for an adsorbent material of the gases at near-ambient temperatures. Specific adsorbent materials are used as a trap, preferentially adsorbing the target gases at high pressure. The process then swings to low pressure to desorb the adsorbed material and flush the adsorbent container so that it can be reused.
## Cylinder markings to identify contents {#cylinder_markings_to_identify_contents}
Any diving cylinder containing a blend of gasses other than standard air is required by most diver training organizations, and some national governments, to be clearly marked to indicate the current gas mixture. In practice it is common to use a printed adhesive label to indicate the type of gas (in this case nitrox), and to add a temporary label to specify the analysis of the current mix.
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# Nitrox
## Regional standards and conventions {#regional_standards_and_conventions}
### European Union {#european_union}
Within the EU, valves with M26x2 outlet thread are recommended for cylinders with increased oxygen content. Regulators for use with these cylinders require compatible connectors, and are not directly connectable with cylinders for compressed air.
### Germany
A nitrox cylinder is specially cleaned and identified. According to EN 144-3 the cylinder colour is overall white with the letter **N** on opposite sides of the cylinder. The fraction of oxygen in the bottle is checked after filling and marked on the cylinder.
### South Africa {#south_africa}
South African National Standard 10019:2008 specifies the colour of all scuba cylinders as Golden yellow with French gray shoulder. This applies to all underwater breathing gases except medical oxygen, which must be carried in cylinders that are Black with a White shoulder. Nitrox cylinders must be identified by a transparent, self-adhesive label with green lettering, fitted below the shoulder. In effect this is green lettering on a yellow cylinder, with a gray shoulder. The composition of the gas must also be specified on the label. In practice this is done by a small additional self-adhesive label marked with the measured oxygen fraction, which is changed when a new mix is filled.
The 2021 revision of SANS 10019 changed the colour specification to Light navy grey for the shoulder, and a different label specification which includes hazard symbols for high-pressure and oxidising materials.
### United States {#united_states}
Every nitrox cylinder should also have a sticker stating whether or not the cylinder is *oxygen clean* and suitable for partial pressure blending. Any oxygen-clean cylinder may have any mix up to 100% oxygen inside. If by some accident an oxygen-clean cylinder is filled at a station that does not supply gas to oxygen-clean standards it is then considered contaminated and must be re-cleaned before a gas containing more than 40% oxygen may again be added. Cylinders marked as \'not oxygen clean\' may only be filled with oxygen-enriched air mixtures from membrane or stick blending systems where the gas is mixed before being added to the cylinder, and to an oxygen fraction not exceeding 40% by volume.
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# Nitrox
## Hazards
Nitrox can be a hazard to the blender and to the user, for different reasons.
### Fire and toxic cylinder contamination from oxygen reactions {#fire_and_toxic_cylinder_contamination_from_oxygen_reactions}
Partial pressure blending using pure oxygen decanted into the cylinder before topping up with air may involve very high oxygen fractions and oxygen partial pressures during the decanting process, which constitute a relatively high fire hazard. This procedure requires care and precautions by the operator, and decanting equipment and cylinders which are clean for oxygen service, but the equipment is relatively simple and inexpensive. Partial pressure blending using pure oxygen is often used to provide nitrox on live-aboard dive boats, but it is also used in some dive shops and clubs.
Any gas which contains a significantly larger percentage of oxygen than air is a fire hazard, and such gases can react with hydrocarbons or lubricants and sealing materials inside the filling system to produce toxic gases, even if a fire is not apparent. Some organisations exempt equipment from oxygen-clean standards if the oxygen fraction is limited to 40% or less.
Among recreational training agencies, only ANDI subscribes to the guideline of requiring oxygen cleaning for equipment used with more than 23% oxygen fraction. The USCG, NOAA, U.S. Navy, OSHA, and the other recreational training agencies accept the limit as 40% as no accident or incident has been known to occur when this guideline has been properly applied. Tens of thousands of recreational divers are trained each year and the overwhelming majority of these divers are taught the \"over 40% rule\". Most nitrox fill stations which supply pre-mixed nitrox will fill cylinders with mixtures below 40% without certification of cleanliness for oxygen service. Luxfer cylinders specify oxygen cleaning for all mixtures exceeding 23.5% oxygen.
The following references for oxygen cleaning specifically cite the \"over 40%\" guideline that has been in widespread use since the 1960s, and consensus at the 1992 Enriched Air Workshop was to accept that guideline and continue the status quo.
- Code of Federal Regulations, Part 1910.430 (i) -- Commercial Diving Operations
- OSHA Oxygen Specifications 1910.420 (1)
- NOAA Oxygen Specifications (appendix D)
- U.S. Navy Oxygen Specifications U.S. MIL-STD-777E (SH) Note K-6-4, Cat. K.6
- U.S. Coast Guard Oxygen Specifications Title 46: Shipping, revisions through 10-1-92. 197.452 Oxygen Cleaning 46 CFR 197.451
Much of the confusion appears to be a result of misapplying PVHO (pressure vessel for human occupancy) guidelines which prescribe a maximum ambient oxygen content of 25% when a human is sealed into a pressure vessel (chamber). The concern here is for a fire hazard to a living person who could be trapped in an oxygen-rich burning environment.
Of the three commonly applied methods of producing enriched air mixes -- continuous blending, partial pressure blending, and membrane separation systems -- only partial pressure blending would require the valve and cylinder components to be oxygen cleaned for mixtures with less than 40% oxygen. The other two methods ensure that the equipment is never subjected to greater than 40% oxygen content.
In a fire, the pressure in a gas cylinder rises in direct proportion to its absolute temperature. If the internal pressure exceeds the mechanical limitations of the cylinder and there are no means to safely vent the pressurized gas to the atmosphere, the vessel will fail mechanically. If the vessel contents are ignitable or a contaminant is present this event may result in a \"fireball\".
### Incorrect gas mix {#incorrect_gas_mix}
Use of a gas mix that differs from the planned mix introduces an increased risk of decompression sickness or an increased risk of oxygen toxicity, depending on the error. It may be possible to simply recalculate the dive plan or set the dive computer accordingly, but in some cases the planned dive may not be practicable.
Many training agencies such as PADI, CMAS, SSI and NAUI train their divers to personally check the oxygen percentage content of each nitrox cylinder before every dive. If the oxygen percentage deviates by more than 1% from the planned mix, the diver must either recalculate the dive plan with the actual mix, or else abort the dive to avoid increased risk of oxygen toxicity or decompression sickness. Under IANTD and ANDI rules for use of nitrox, which are followed by dive resorts around the world, filled nitrox cylinders are signed out personally in a blended gas records book, which contains, for each cylinder and fill, the cylinder number, the measured oxygen fraction by percentage, the calculated maximum operating depth for that mix, and the signature of the receiving diver, who should have personally measured the oxygen fraction before taking delivery. All of these steps reduce risk but increase complexity of operations as each diver must use the specific cylinder they have checked out. In South Africa, the national standard for handling and filling portable cylinders with pressurised gases (SANS 10019) requires that the cylinder be labelled with a sticker identifying the contents as nitrox, and specifying the oxygen fraction. Similar requirements may apply in other countries.
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# Nitrox
## History
In 1874, Henry Fleuss made what was possibly the first Nitrox dive using a rebreather.
In 1911, Draeger of Germany tested an injector operated rebreather backpack for a standard diving suit. This concept was produced and marketed as the DM20 oxygen rebreather system and the DM40 nitrox rebreather system, in which air from one cylinder and oxygen from a second cylinder were mixed during injection through a nozzle which circulated the breathing gas through the scrubber and the rest of the loop. The DM40 was rated for depths up to 40m.
Christian J. Lambertsen proposed calculations for nitrogen addition to prevent oxygen toxicity in divers utilizing nitrogen--oxygen rebreather diving.
In World War II or soon after, British commando frogmen and clearance divers started occasionally diving with oxygen rebreathers adapted for semi-closed-circuit nitrox (which they called \"mixture\") diving by fitting larger cylinders and carefully setting the gas flow rate using a flow meter. These developments were kept secret until independently duplicated by civilians in the 1960s.
Lambertson published a paper on nitrox in 1947.
In the 1950s, the United States Navy (USN) documented enriched oxygen gas procedures for military use of what we today call nitrox, in the US Navy Diving Manual.
In 1955, E. Lanphier described the use of nitrogen--oxygen diving mixtures, and the equivalent air depth method for calculating decompression from air tables.
In the 1960s, A. Galerne used on-line blending for commercial diving.
In 1970, Morgan Wells, who was the first director of the National Oceanographic and Atmospheric Administration (NOAA) Diving Center, began instituting diving procedures for oxygen-enriched air. He introduced the concept of Equivalent Air Depth (EAD). He also developed a process for mixing oxygen and air which he called a continuous blending system. For many years Wells\' invention was the only practical alternative to partial pressure blending. In 1979 NOAA published Wells\' procedures for the scientific use of nitrox in the NOAA Diving Manual.
In 1985 Dick Rutkowski, a former NOAA diving safety officer, formed IAND (International Association of Nitrox Divers) and began teaching nitrox use for recreational diving. This was considered dangerous by some, and met with heavy skepticism by the diving community.
In 1989, the Harbor Branch Oceanographic institution workshop addressed blending, oxygen limits and decompression issues.
In 1991, Bove, Bennett and *Skin Diver* magazine took a stand against nitrox use for recreational diving. *Skin Diver* editor Bill Gleason dubbed nitrox the \"Voodoo Gas\". The annual DEMA show (held in Houston, Texas that year) banned nitrox training providers from the show. This caused a backlash, and when DEMA relented, a number of organizations took the opportunity to present nitrox workshops outside the show.
In 1992, the Scuba Diving Resources Group organised a workshop where some guidelines were established, and some misconceptions addressed.
In 1992, BSAC banned its members from using nitrox during BSAC activities. IAND\'s name was changed to the International Association of Nitrox and Technical Divers (IANTD), the T being added when the European Association of Technical Divers (EATD) merged with IAND. In the early 1990s, these agencies were teaching nitrox, but the main scuba agencies were not. Additional new organizations, including the American Nitrox Divers International (ANDI) -- which invented the term \"Safe Air\" for marketing purposes -- and Technical Diving International (TDI) were begun. NAUI became the first existing major recreational diver training agency to sanction nitrox.
In 1993, the Sub-Aqua Association was the first UK recreational diving training agency to acknowledge and endorse the Nitrox training their members had undertaken with one of the tech agencies. The SAA\'s first recreational Nitrox qualification was issued in April 1993. The SAA\'s first Nitrox instructor was Vic Bonfante and he was certified in September 1993.
Meanwhile, diving stores were finding a purely economic reason to offer nitrox: not only was an entire new course and certification needed to use it, but instead of cheap or free tank fills with compressed air, dive shops found they could charge premium amounts of money for custom-gas blending of nitrox to their ordinary, moderately experienced divers. With the new dive computers which could be programmed to allow for the longer bottom-times and shorter residual nitrogen times that nitrox gave, the incentive for the sport diver to use the gas increased.
In 1993, *Skin Diver* magazine, the leading recreational diving publication at the time, published a three-part series arguing that nitrox was unsafe for sport divers. DiveRite manufactured the first nitrox-compatible dive computer, called the Bridge, the aquaCorps TEK93 conference was held in San Francisco, and a practicable oil limit of 0.1 mg/m^3^ for oxygen compatible air was set. The Canadian armed forces issued EAD tables with an upper PO~2~ of 1.5 ATA.
In 1994, John Lamb and Vandagraph launched the first oxygen analyzer built specifically for Nitrox and mixed-gas divers, at the Birmingham Dive Show.
In 1994, BSAC reversed its policy on Nitrox and announced BSAC nitrox training to start in 1995.
In 1996, the Professional Association of Diving Instructors (PADI) announced full educational support for nitrox. While other mainline scuba organizations had announced their support of nitrox earlier, it was PADI\'s endorsement that established nitrox as a standard recreational diving option.
In 1997, ProTec started with Nitrox 1 (recreational) and Nitrox 2 (technical). A German ProTec Nitrox manual (ref to the 6th edition) has been published.
In 1999, a survey by R.W. Hamilton showed that over hundreds of thousands of nitrox dives, the DCS record is good. Nitrox had become popular with recreational divers, but not used much by commercial divers who tend to use surface supplied breathing apparatus. The OSHA accepted a petition for a variance from the commercial diving regulations for recreational scuba instructors.
The 2001 edition of the *NOAA Diving Manual* included a chapter intended for Nitrox training.
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# Nitrox
## In nature {#in_nature}
At times in the geological past, the Earth\'s atmosphere contained much more than 20% oxygen: e.g. up to 35% in the Upper Carboniferous period. This let animals absorb oxygen more easily and influenced their evolutionary patterns
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# Eightfold path (policy analysis)
\_\_NOTOC\_\_ `{{Use dmy dates|date=February 2025}}`{=mediawiki} The **eightfold path** is a method of policy analysis assembled by Eugene Bardach, a professor at the Goldman School of Public Policy at the University of California, Berkeley. It is outlined in his book *A Practical Guide for Policy Analysis: The Eightfold Path to More Effective Problem Solving*, which is now in its seventh edition. The book is commonly referenced in public policy and public administration scholarship.
Bardach\'s procedure is as follows:
1. Define the problem
2. Assemble the evidence
3. Construct the alternatives
4. Select the criteria
5. Project the outcomes
6. Confront the trade-offs
7. Decide
8. Tell your story
A possible ninth step, based on Bardach\'s own writing, might be \"repeat steps 1--8 as necessary.\"
The method is named after the Buddhist Noble Eightfold Path, but otherwise has no relation to it.
## New York taxi driver test {#new_york_taxi_driver_test}
The New York taxi driver test is a technique for evaluating the effectiveness of communication between policy makers and analysts. Bardach contends that policy explanations must be clear and down-to-earth enough for a taxi driver to be able to understand the premise during a trip through city streets. The New York taxi driver is presumed to be both a non-specialist and a tough customer
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# European Commission
{{ Infobox executive government
`| nativename = ``{{Name in official languages
| name = Name in official languages
| bg = Европейска комисия
| hr = Europska komisija
| cs = Evropská komise
| da = Europa-Kommissionen
| nl = Europese Commissie
| en = European Commission
| et = Euroopa Komisjon
| fi = Euroopan komissio
| fr = Commission européenne
| de = Europäische Kommission
| el = Ευρωπαϊκή Επιτροπή
| hu = Európai Bizottság
| ga = Coimisiún Eorpach
| it = Commissione europea
| lv = Eiropas Komisija
| lt = Europos Komisija
| mt = Kummissjoni Ewropea
| pl = Komisja Europejska
| pt = Comissão Europeia
| ro = Comisia Europeană
| sk = Európska komisia
| sl = Evropska komisija
| es = Comisión Europea
| sv = Europeiska kommissionen
}}`{=mediawiki}\
`| border = `\
`| image = Logo of the European Commission (2025, English, horizontal).svg`\
`| image_size = 250px`\
`| alt = `\
`| image2 = `\
`| image_size2 = `\
`| alt2 = `\
`| caption = `\
`| date_established = ``{{Start date and age|1958|01|16|df=y}}`{=mediawiki}\
`| date_dissolved = `\
`| state = `\
`| country = ``{{Collapsible list
| framestyle = text-align: left; border: 0; padding: 0; line-height: 16px; white-space: nowrap;
| titlestyle = background: transparent; text-align: left; font-weight: normal;
| title = [[Member state of the European Union|27 member states]]
| {{Flaglist|Austria}}
| {{Flaglist|Belgium}}
| {{Flaglist|Bulgaria}}
| {{Flaglist|Croatia}}
| {{Flaglist|Cyprus}}
| {{Flaglist|Czech Republic}}
| {{Flaglist|Denmark}}
| {{Flaglist|Estonia}}
| {{Flaglist|Finland}}
| {{Flaglist|France}}
| {{Flaglist|Germany}}
| {{Flaglist|Greece}}
| {{Flaglist|Hungary}}
| {{Flaglist|Ireland}}
| {{Flaglist|Italy}}
| {{Flaglist|Latvia}}
| {{Flaglist|Lithuania}}
| {{Flaglist|Luxembourg}}
| {{Flaglist|Malta}}
| {{Flaglist|Netherlands}}
| {{Flaglist|Poland}}
| {{Flaglist|Portugal}}
| {{Flaglist|Romania}}
| {{Flaglist|Slovakia}}
| {{Flaglist|Slovenia}}
| {{Flaglist|Spain}}
| {{Flaglist|Sweden}}
}}`{=mediawiki}\
`| polity = ``European Union`\
`| leader_title = ``President of the Commission`` (``Ursula von der Leyen`` since 1 December 2019)`\
`| leader_name = ``Ursula von der Leyen`\
`| appointed = Nominated by the ``European Council`` and elected by the ``European Parliament`\
`| main_organ = ``College of Commissioners`\
`| ministries = ``{{Collapsible list
| framestyle = text-align: left; border: 0; padding: 0; line-height: 16px; white-space: nowrap;
| titlestyle = background: transparent; text-align: left; font-weight: normal;
| title = 33
| bullets = true
| [[Directorate-General for Agriculture and Rural Development|Agriculture and Rural Development]]
| [[Directorate-General for Budget|Budget]]
| [[Directorate-General for Climate Action|Climate Action]]
| [[Directorate-General for Communication|Communication]]
| [[Directorate-General for Communications Networks, Content and Technology|Communications Networks, Content and Technology]]
| [[Directorate-General for Competition|Competition]]
| [[Directorate-General for Economic and Financial Affairs|Economic and Financial Affairs]]
| [[Directorate-General for Education, Youth, Sport and Culture|Education and Culture]]
| [[Directorate-General for Employment, Social Affairs and Inclusion|Employment, Social Affairs and Inclusion]]
| [[Directorate-General for Energy|Energy]]
| [[Directorate-General for the Environment|Environment]]
| [[Directorate-General for European Civil Protection and Humanitarian Aid Operations|European Civil Protection and Humanitarian Aid Operations]]
| [[Eurostat]]
| [[Directorate-General for Financial Stability, Financial Services and Capital Markets Union|Financial Stability, Financial Services and Capital Markets Union]]
| [[Directorate-General for Health and Food Safety|Health and Food Safety]]
| [[Directorate-General for Human Resources and Security|Human Resources and Security]]
| [[Directorate-General for Informatics|Informatics]]
| [[Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs|Internal Market, Industry, Entrepreneurship and SMEs]]
| [[Directorate-General for International Cooperation and Development|International Cooperation and Development]]
| [[Directorate-General for Interpretation|Interpretation]]
| [[Joint Research Centre]]
| [[Directorate-General for Justice and Consumers|Justice and Consumers]]
| [[Directorate-General for Maritime Affairs and Fisheries|Maritime Affairs and Fisheries]]
| [[Directorate-General for Migration and Home Affairs|Migration and Home Affairs]]
| [[Directorate-General for Mobility and Transport|Mobility and Transport]]
| [[Directorate-General for European Neighbourhood Policy and Enlargement Negotiations|Neighbourhood and Enlargement Negotiations]]
| [[Directorate-General for Regional and Urban Policy|Regional and Urban Policy]]
| [[Directorate-General for Research and Innovation|Research and Innovation]]
| [[Directorate-General for Taxation and Customs Union (European Commission)|Taxation and Customs Union]]
| [[Directorate-General for Trade|Trade]]
| [[Directorate-General for Translation|Translation]]
}}`{=mediawiki}\
`| responsible = ``{{Unbulleted list
| European Parliament
}}`{=mediawiki}\
`| address = ``{{Unbulleted list
| [[City of Brussels|Brussels]], Belgium
| [[Luxembourg City]], Luxembourg
}}`{=mediawiki}\
`| url = ``{{URL|ec.europa.eu}}`{=mediawiki}\
`}}`
The **European Commission** (**EC**) is the primary executive arm of the European Union (EU). It operates as a cabinet government, with a number of members of the Commission (directorial system, informally known as \"commissioners\") corresponding to two thirds of the number of member states, unless the European Council, acting unanimously, decides to alter this number. The current number of commissioners is 27, including the president. It includes an administrative body of about 32,000 European civil servants. The commission is divided into departments known as Directorates-General (DGs) that can be likened to departments or ministries each headed by a director-general who is responsible to a commissioner.
Currently, there is one member per member state, but members are bound by their oath of office to represent the general interest of the EU as a whole rather than their home state. The Commission president (currently Ursula von der Leyen) is proposed by the European Council (the 27 heads of state/governments) and elected by the European Parliament. The Council of the European Union then nominates the other members of the Commission in agreement with the nominated president, and the 27 members as a team are then subject to a vote of approval by the European Parliament. The current Commission is the von der Leyen Commission II, which took office in December 2024, following the European Parliament elections in June of the same year.
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# European Commission
## History
The European Commission derives from one of the five key institutions created in the supranational European Community system, following the proposal of Robert Schuman, French Foreign Minister, on 9 May 1950. Originating in 1951 as the High Authority in the European Coal and Steel Community, the commission has undergone numerous changes in power and composition under various presidents, involving three Communities.
### Establishment
The first Commission originated in 1951 as the nine-member \"High Authority\" under President Jean Monnet (see Monnet Authority). The High Authority was the supranational administrative executive of the new European Coal and Steel Community (ECSC). It took office first on 10 August 1952 in Luxembourg City. In 1958, the Treaties of Rome had established two new communities alongside the ECSC: the European Economic Community (EEC) and the European Atomic Energy Community (Euratom). However, their executives were called \"Commissions\" rather than \"High Authorities\". The reason for the change in name was the new relationship between the executives and the Council. Some states, such as France, expressed reservations over the power of the High Authority and wished to limit it by giving more power to the Council rather than the new executives.
Louis Armand led the first Commission of Euratom. Walter Hallstein led the first Commission of the EEC, holding the first formal meeting on 16 January 1958 at the Château of Val-Duchesse. It achieved agreement on a contentious cereal price accord, as well as making a positive impression upon third countries when it made its international debut at the Kennedy Round of General Agreement on Tariffs and Trade (GATT) negotiations. Hallstein notably began the consolidation of European law and started to have a notable impact on national legislation. Little heed was taken of his administration at first but, with help from the European Court of Justice, his Commission stamped its authority solidly enough to allow future Commissions to be taken more seriously. In 1965, however, accumulating differences between the French government of Charles de Gaulle and the other member states on various subjects (British entry, direct elections to Parliament, the Fouchet Plan and the budget) triggered the \"empty chair\" crisis, ostensibly over proposals for the Common Agricultural Policy. Although the institutional crisis was solved the following year, it cost Étienne Hirsch his presidency of Euratom and later Walter Hallstein the EEC presidency, despite his otherwise being viewed as the most \'dynamic\' leader until Jacques Delors.
### Early development {#early_development}
The three bodies, collectively named the **European Executives**, co-existed until 1 July 1967 when, under the Merger Treaty, they were combined into a single administration under President Jean Rey. Owing to the merger, the Rey Commission saw a temporary increase to 14 members---although subsequent Commissions were reduced back to nine, following the formula of one member for small states and two for larger states. The Rey Commission completed the Community\'s customs union in 1968 and campaigned for a more powerful, elected, European Parliament. Despite Rey being the first President of the combined communities, Hallstein is seen as the first President of the modern Commission.
The Malfatti and Mansholt Commissions followed with work on monetary co-operation and the first enlargement to the north in 1973. With that enlargement, the College of Commissioners membership increased to thirteen under the Ortoli Commission (the United Kingdom as a large member was granted two Commissioners), which dealt with the enlarged community during economic and international instability at that time. The external representation of the Community took a step forward when President Roy Jenkins, recruited to the presidency in January 1977 from his role as Home Secretary of the United Kingdom\'s Labour government, became the first President to attend a G8 summit on behalf of the Community. Following the Jenkins Commission, Gaston Thorn\'s Commission oversaw the Community\'s enlargement to the south, in addition to beginning work on the Single European Act.
### Jacques Delors {#jacques_delors}
*Main article: Delors Commission* The Commission headed by Jacques Delors was seen as giving the Community a sense of direction and dynamism. Delors and his College are also considered as the \"founding fathers of the euro\". The *International Herald Tribune* noted the work of Delors at the end of his second term in 1992: \"Mr. Delors rescued the European Community from the doldrums. He arrived when Europessimism was at its worst. Although he was a little-known former French finance minister, he breathed life and hope into the EC and into the dispirited Brussels Commission. In his first term, from 1985 to 1988, he rallied Europe to the call of the single market, and when appointed to a second term he began urging Europeans toward the far more ambitious goals of economic, monetary, and political union\".
### Jacques Santer {#jacques_santer}
The successor to Delors was Jacques Santer. As a result of a fraud and corruption scandal, the entire Santer Commission was forced by the Parliament to resign in 1999. These frauds were revealed by internal auditor Paul van Buitenen, with French commissioner Édith Cresson being the main target of the allegations.
That was the first time a College of Commissioners had been forced to resign *en masse*, and represented a shift of power towards the Parliament. However, the Santer Commission did carry out work on the Treaty of Amsterdam and the euro. In response to the scandal, the European Anti-Fraud Office (OLAF) was created.
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# European Commission
## History
### Romano Prodi {#romano_prodi}
Following Santer, Romano Prodi took office. The Amsterdam Treaty had increased the commission\'s powers and Prodi was dubbed by the press as something akin to a Prime Minister. Powers were strengthened again; the Treaty of Nice, signed in 2001, gave the Presidents more power over the composition of the College of Commissioners.
### José Manuel Barroso {#josé_manuel_barroso}
José Manuel Barroso became president in 2004: the Parliament once again asserted itself in objecting to the proposed membership of the Barroso Commission. Owing to this opposition, Barroso was forced to reshuffle his College before taking office. The Barroso Commission was also the first full Commission since the enlargement in 2004 to 25 members; hence, the number of Commissioners at the end of the Prodi Commission had reached 30. As a result of the increase in the number of states, the Amsterdam Treaty triggered a reduction in the number of Commissioners to one per state, rather than two for the larger states.
Allegations of fraud and corruption were again raised in 2004 by former chief auditor Jules Muis. A Commission officer, Guido Strack, reported alleged fraud and abuses in his department in the years 2002--2004 to OLAF, and was fired as a result. In 2008, Paul van Buitenen (the former auditor known from the Santer Commission scandal) accused the European Anti-Fraud Office (OLAF) of a lack of independence and effectiveness.
Barroso\'s first Commission term expired on 31 October 2009. Under the Treaty of Nice, the first Commission to be appointed after the number of member states reached 27 would have to be reduced to \"less than the number of Member States\". The exact number of Commissioners was to be decided by a unanimous vote of the European Council, and membership would rotate equally between member states. Following the accession of Romania and Bulgaria in January 2007, this clause took effect for the next Commission. The Treaty of Lisbon, which came into force on 1 December 2009, mandated a reduction of the number of commissioners to two-thirds of member-states from 2014 unless the Council decided otherwise. Membership would rotate equally and no member state would have more than one Commissioner. However, the treaty was rejected by voters in Ireland in 2008 with one main concern being the loss of their Commissioner. Hence a guarantee given for a rerun of the vote was that the council would use its power to amend the number of Commissioners upwards. However, according to the treaties it still has to be fewer than the total number of members, thus it was proposed that the member state that does not get a Commissioner would get the post of High Representative -- the so-called 26+1 formula. This guarantee (which may find its way into the next treaty amendment, probably in an accession treaty) contributed to the Irish approving the treaty in a second referendum in 2009.
Lisbon also combined the posts of European Commissioner for External Relations with the council\'s High Representative for the Common Foreign and Security Policy. This post, also a Vice-president of the Commission, would chair the Council of the European Union\'s foreign affairs meetings as well as the commission\'s external relations duties. The treaty further provides that the most recent European elections should be \"*taken into account*\" when appointing the President of the European Commission, and although they are still proposed by the European Council; the European Parliament \"*elects*\" candidates to the office, rather than \"*approves*\" them as under the Treaty of Nice.
The Barroso Commission is, in reaction to Euroscepticism, said to have toned down enforcement to increase integration.
### Jean-Claude Juncker {#jean_claude_juncker}
In 2014, Jean-Claude Juncker became President of the European Commission.
Juncker appointed his previous campaign director and head of the transition team, Martin Selmayr, as his chief of cabinet. During the Juncker presidency Selmayr has been described as \"the most powerful EU chief of staff ever.\"
### Ursula von der Leyen {#ursula_von_der_leyen}
*Main article: Von der Leyen Commission I, Von der Leyen Commission II*
In 2019, Ursula von der Leyen was appointed as President of the European Commission. She submitted the guidelines of her policy to the European Parliament on 16 July 2019, following her confirmation. She had not been considered a likely candidate (in general, the elected candidate is determined, according to the results of the European election, as winner of the internal election into the dominant European party known as \"*\[\[spitzenkandidat\]\]*\"). While the European People\'s Party had won the European Parliament election, they had performed worse than expected and therefore nominated von der Leyen instead of Manfred Weber, their original candidate. On 9 September, the Council of the European Union declared a list of candidate-commissioners, which are sent to Brussels by the governments of each member state and which had to be officially approved by the parliament.
In September 2024, Von der Leyen revealed her new team of European Commissioners, marking a shift to a \"leaner\" and more interconnected structure. The lineup featured six executive vice-presidents (EVPs) from France, Finland, Estonia, Italy, Romania, and Spain. These EVPs, including Teresa Ribera and Stéphane Séjourné, were tasked with overseeing various clusters of Commissioners and steering key policy areas such as prosperity, security, and democracy. Raffaele Fitto was appointed despite criticism from European socialists over his hard-right affiliations. Other notable appointments included Kaja Kallas as EVP for Foreign and Security Policy, and Henna Virkkunen as EVP for Tech Sovereignty and Digital Technologies. The Commission also introduced new roles like the Commissioner for Defence and Security and the Commissioner for the Mediterranean.
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# European Commission
## Powers and functions {#powers_and_functions}
The commission was set up from the start to act as an independent supranational authority separate from governments; it has been described as \"the only body paid to think European\". The members are proposed by their member state governments, one from each. However, they are bound to act independently -- free from other influences such as those governments which appointed them. This is in contrast to the Council of the European Union, which represents governments, the European Parliament, which represents citizens, the Economic and Social Committee, which represents organised civil society, and the Committee of the Regions, which represents local and regional authorities.
Through Article 17 of the Treaty on European Union the commission has several responsibilities: to develop medium-term strategies; to draft legislation and arbitrate in the legislative process; to represent the EU in trade negotiations; to make rules and regulations, for example in competition policy; to draw up the budget of the European Union; and to scrutinise the implementation of the treaties and legislation. The rules of procedure of the European Commission set out the commission\'s operation and organisation.
### Executive power {#executive_power}
Before the Treaty of Lisbon came into force, the executive power of the EU was held by the council: it conferred on the Commission such powers for it to exercise. However, the council was allowed to withdraw these powers, exercise them directly, or impose conditions on their use. This aspect has been changed by the Treaty of Lisbon, after which the Commission exercises its powers just by virtue of the treaties. Powers are more restricted than most national executives, in part due to the commission\'s lack of power over areas like foreign policy -- that power is held by the Council of the European Union and the European Council, which some analysts have described as another executive.
Considering that under the Treaty of Lisbon, the European Council has become a formal institution with the power of appointing the commission, it could be said that the two bodies hold the executive power of the EU (the European Council also holds individual national executive powers). However, it is the Commission that currently holds most of the executive power over the European Union.
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# European Commission
## Powers and functions {#powers_and_functions}
### Legislative initiative {#legislative_initiative}
The Commission differs from the other institutions in that it alone has legislative initiative in the EU. Only the commission can make formal proposals for legislation: they cannot originate in the legislative branches. Under the Treaty of Lisbon, no legislative act is allowed in the field of the Common Foreign and Security Policy. In the other fields, the Council and Parliament can request legislation; in most cases the Commission initiates on the basis of these proposals. This monopoly is designed to ensure coordinated and coherent drafting of EU law. This monopoly has been challenged by some who claim the Parliament should also have the right, with most national parliaments holding the right in some respects. However, the Council and Parliament may request the commission to draft legislation, though the Commission does have the power to refuse to do so as it did in 2008 over transnational collective conventions. Under the Lisbon Treaty, EU citizens are also able to request the commission to legislate in an area via a petition carrying one million signatures, but this is not binding.
The commission\'s powers in proposing law have usually centred on economic regulation. It has put forward a large number of regulations based on a \"precautionary principle\". This means that pre-emptive regulation takes place if there is a credible hazard to the environment or human health: for example on tackling climate change and restricting genetically modified organisms. The European Commission has committed EU member states to carbon neutrality by 2050. This is opposed to weighting regulations for their effect on the economy. Thus, the Commission often proposes stricter legislation than other countries. Owing to the size of the European market, this has made EU legislation an important influence in the global market. On February 23, 2022, the European Commission published the Corporate Sustainability Due Diligence Directive which establishes a framework of due diligence for companies to identify actual or potential risks and harm to human rights and the environment as well as establishing processes and standards to diminish these risks. The Directive is expected to be officially adopted in 2024 and then be incorporated into domestic laws within two years by all of the European Union member states.
Recently the commission has moved into creating European criminal law. In 2006, a toxic waste spill off the coast of Côte d\'Ivoire, from a European ship, prompted the commission to look into legislation against toxic waste. at that time did not even have a crime against shipping toxic waste; this led the Commissioners Franco Frattini and Stavros Dimas to put forward the idea of \"ecological crimes\". Their right to propose criminal law was challenged in the European Court of Justice but upheld. `{{asof|2007|post=,}}`{=mediawiki} the only other criminal law proposals which have been brought forward are on the intellectual property rights directive, and on an amendment to the 2002 counter-terrorism framework decision, outlawing terrorism‑related incitement, recruitment (especially via the internet) and training.
### Enforcement
Once legislation is passed by the Council and Parliament, it is the commission\'s responsibility to ensure it is implemented. It does this through the member states or through its agencies. In adopting the necessary technical measures, the commission is assisted by committees made up of representatives of member states and of the public and private lobbies (a process known in jargon as \"comitology\"). Furthermore, the commission is responsible for the implementation of the EU budget, ensuring, along with the Court of Auditors, that EU funds are correctly spent.
In particular the commission has a duty to ensure the treaties and law are upheld, potentially by taking member states or other institutions to the Court of Justice in a dispute. In this role it is known informally as the \"Guardian of the Treaties\". Finally, the Commission provides some external representation for the Union, alongside the member states and the Common Foreign and Security Policy, representing the Union in bodies such as the World Trade Organization. It is also usual for the President to attend meetings of the G7.
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# European Commission
## College of Commissioners {#college_of_commissioners}
The commission is composed of a \"College of Commissioners\" of `{{EUnum}}`{=mediawiki} members, including the President and vice-presidents. Even though each member is nominated on the basis of the suggestions made by the national governments, one per state, they do not represent their state in the commission. In practice, however, they do occasionally press for their national interest. Once proposed, the President delegates portfolios among each of the members. The power of a Commissioner largely depends upon their portfolio, and can vary over time. For example, the Education Commissioner has been growing in importance, in line with the rise in the importance of education and culture in European policy-making. Another example is the Competition Commissioner, who holds a highly visible position with global reach. Before the commission can assume office, the college as a whole must be approved by the Parliament. Commissioners are supported by their personal cabinet who give them political guidance, while the Civil Service (the DGs, see below) deal with technical preparation.
### Appointment
The President of the Commission is appointed in an indirect election. The candidate is first selected by the European Council, according to the Qualified Majority Vote (QMV), taking into account the latest parliamentary elections (any person from the largest party can be picked). That candidate then faces approval by the European Parliament. If the European Parliament fails to elect the candidate, the European Council shall propose another within one month.
Following the selection of the President, and the appointment of the High Representative by the European Council, each Commissioner is proposed by their member state (except for those states who provided the President and High Representative) in consultation with the Commission President and the Council of the European Union, who formally adopts the list of candidates. The President\'s proposed College of Commissioners is then subject to hearings at the European Parliament which will question them and then vote on their suitability as a whole. If the European Parliament submits a negative opinion of a candidate, the President must either reshuffle them or request a new candidate from the member state to avoid the college\'s outright rejection by the European Parliament. Once the college is approved by parliament, it is formally appointed following a QMV vote by the European Council.
Following the college\'s appointment, the President appoints a number of Vice-presidents from among the commissioners. Vice-presidents manage policy areas involving multiple Commissioners. One of these includes the High Representative, who is automatically one of the Vice-presidents *ex officio* rather than by appointment and confirmation. Commonly referred to as the \'HR/VP\' position, the High Representative also coordinates commissioners\' activities involving the external relations and defence cooperation of the European Union. The von der Leyen Commission also created the position of more senior Executive Vice-presidents, appointed from the three largest political groups in the European Parliament. Unlike the other vice-presidents, their mission is to manage the incumbent Commission\'s top priority policy areas, for which they receive additional support from a dedicated Directorate-General.
### Dismissal
The European Parliament can dissolve the College of Commissioners as a whole following a vote of no-confidence, which requires a two-thirds vote.
Only the President can request the resignation of an individual Commissioner. However, individual Commissioners, by request of the council or Commission, can be compelled to retire on account of a breach of obligation(s) and if so ruled by the European Court of Justice (Art. 245 and 247, Treaty on the Functioning of the European Union).
### Political styles {#political_styles}
The Barroso Commission took office in late 2004 after being delayed by objections from the Parliament, which forced a reshuffle. In 2007 the Commission increased from 25 to 27 members with the accession of Romania and Bulgaria who each appointed their own Commissioners. With the increasing size of the commission, Barroso adopted a more presidential style of control over the college, which earned him some criticism.
However, under Barroso, the commission began to lose ground to the larger member states as countries such as France, the UK and Germany sought to sideline its role. This has increased with the creation of the President of the European Council under the Treaty of Lisbon. There has also been a greater degree of politicisation within the Commission.
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# European Commission
## Administration
The commission is divided into departments known as Directorates-General (DGs) that can be likened to departments or ministries. Each covers a specific policy area such as agriculture or justice and citizens\' rights or internal services such as human resources and translation and is headed by a director-general who is responsible to a commissioner. A commissioner\'s portfolio can be supported by numerous DGs; they prepare proposals for them and if approved by a majority of commissioners proposals go forward to the Parliament and Council for consideration. The Commission\'s civil service is headed by a Secretary General. The position is currently held by Ilze Juhansone. The rules of procedure of the European Commission set out the commission\'s operation and organisation.
There has been criticism from a number of people that the highly fragmented DG structure wastes a considerable amount of time in turf wars as the different departments and Commissioners compete with each other. Furthermore, the DGs can exercise considerable control over a Commissioner with the Commissioner having little time to learn to assert control over their staff.
According to figures published by the commission, 23,803 persons were employed by the commission as officials and temporary agents in September 2012. In addition to these, 9230 \"external staff\" (e.g. Contractual agents, detached national experts, young experts, trainees etc.) were employed. The single largest DG is the Directorate-General for Translation, with a 2309-strong staff, while the largest group by nationality is Belgian (18.7%), probably due to a majority (17,664) of staff being based in the country.
### Press
Communication with the press is handled by the Directorate-General Communication. The commission\'s chief spokesperson is Eric Mamer who holds the midday press briefings, commonly known as the \"Midday Presser\". It takes place every weekday in the commission\'s press room at the Berlaymont where journalists may ask questions to the Commission officials on any topic and legitimately expect to get an \"on the record\" answer for live TV. Such a situation is unique in the world.
As an integral part of the Directorate-General for Communication, the Spokesperson\'s Service, in coordination with the Executive Communication Adviser in the President\'s Cabinet, supports the President and Commissioners so that they can communicate effectively. On political communication matters, the chief spokesperson reports directly to the President of the European Commission.
It has been noted by one researcher that the press releases issued by the commission are uniquely political. A release often goes through several stages of drafting which emphasises the role of the commission and is used \"for justifying the EU and the Commission\" increasing their length and complexity. Where there are multiple departments involved a press release can also be a source of competition between areas of the Commission and Commissioners themselves. This also leads to an unusually high number of press releases, and is seen as a unique product of the EU\'s political set-up.
There is a larger press corps in Brussels than Washington, D.C.; in 2020, media outlets in every Union member-state had a Brussels correspondent. Although there has been a worldwide cut in journalists, the considerable press releases and operations such as Europe by Satellite and EuroparlTV leads many news organisations to believe they can cover the EU from these source and news agencies. The Commission shut down Presseurop on 20 December 2013, though the decision was criticised.
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# European Commission
## Legitimacy and criticism {#legitimacy_and_criticism}
As the commission is the executive branch, candidates are chosen individually by the `{{EUnum}}`{=mediawiki} national governments. Within the EU, the legitimacy of the commission is mainly drawn from the vote of approval that is required from the European Parliament, along with its power to dismiss the body. Eurosceptics have therefore raised the concern of the relatively low turnout (often less than 50%) in elections for the European Parliament since 1999. While that figure may be higher than that of some national elections, including the off-year elections of the United States Congress, the fact that there are no direct elections for the position of Commission President calls the position\'s legitimacy into question in the eyes of some Eurosceptics. The fact that the commission can directly decide (albeit with oversight from specially formed \'comitology committees\') on the shape and character of implementing legislation further raises concerns about democratic legitimacy.
Even though democratic structures and methods are changing there is not such a mirror in creating a European civil society. The Treaty of Lisbon may go some way to resolving the perceived deficit in creating greater democratic controls on the commission, including enshrining the procedure of linking elections to the selection of the Commission president. Historically, the commission had indeed been seen as a technocratic expert body which, akin with institutions such as independent central banks, deals with technical areas of policy and therefore ought to be removed from party politics. From this viewpoint, electoral pressures would undermine the commission\'s role as an independent regulator. Defenders of the Commission point out that legislation must be approved by the Council in all areas (the ministers of member states) and the European Parliament in most areas before it can be adopted, thus the amount of legislation which is adopted in any one country without the approval of its government is limited.
In 2009 the European ombudsman published statistics of citizens\' complaints against EU institutions, with most of them filed against the commission (66%) and concerning lack of transparency (36%). In 2010 the commission was sued for blocking access to documents on EU biofuel policy. This happened after media accused the Commission of blocking scientific evidence against biofuel subsidies. Lack of transparency, unclear lobbyist relations, conflicts of interests and excessive spending of the commission was highlighted in a number of reports by internal and independent auditing organisations. It has also been criticised on IT-related issues, particularly with regard to Microsoft. In September 2020, the European Commission put forward an Anti-Racism Action Plan to tackle the structural racism in the European Union, including measures to address the lack of racial diversity among the European decision makers in Brussels, as denounced by the #BrusselsSoWhite movement.
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# European Commission
## Initiatives
### Anti-terrorism {#anti_terrorism}
The European Commission has an Action Plan to enhance preparedness against chemical, biological, radiological and nuclear (CBRN) security risks as part of its anti-terrorism package released in October 2017. In recent times Europe has seen an increased threat level`{{Quantify|date=April 2022}}`{=mediawiki}`{{From whom?|date=April 2022}}`{=mediawiki} of CBRN attacks.`{{According to whom|date=April 2022}}`{=mediawiki} As such, the European Commission\'s preparedness plan is important, said Steven Neville Chatfield, a director for the Centre for Emergency Preparedness and Response in the United Kingdom\'s Health Protection Agency. For the first time, the European Commission proposed that medical preparedness for CBRN attack threats is a high priority. \"The European Commission\'s (EC) Action Plan to enhance preparedness against CBRN security risks is part of its anti-terrorism package released in October 2017, a strategy aimed at better protecting the more than 511 million citizens across the 27 member states of the European Union (EU).\"
### COVID-19 response {#covid_19_response}
The European Commission organized a video conference of world leaders on 4 May 2020 to raise funds for COVID-19 vaccine development. US\$8 billion was raised.
The European Commission issued a new multi-year data plan in February 2020 pushing the digitalization of all aspects of EU society for the benefit of civic and economic growth.
The goal of this data strategy is to create a single market for data in which data flows across the EU and across sectors while maintaining full respect for privacy and data protection, where access rules are fair, and where the European economy benefits enormously as a global player as a result of the new data economy.
## Location
The commission\'s political seat is in Brussels with the President\'s office and the commission\'s meeting room on the 13th floor of the Berlaymont building. The commission also operates out of numerous other buildings in Brussels and Luxembourg City. When the Parliament is meeting in Strasbourg, the Commissioners also meet there in the Winston Churchill building to attend the Parliament\'s debates. The Members of the Commission and their \"cabinets\" (immediate teams) are also based in the Berlaymont building in Brussels. Additionally, the European Commission has in-house scientific facilities that support it in: Ispra, Italy; Petten, Netherlands; Karlsruhe, Germany; Geel, Belgium and Seville, Spain. In Grange, County Meath, Ireland, a Commission site is hosting part of DG Santè
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# Linear filter
**Linear filters** process time-varying input signals to produce output signals, subject to the constraint of linearity. In most cases these linear filters are also time invariant (or shift invariant) in which case they can be analyzed exactly using LTI (\"linear time-invariant\") system theory revealing their transfer functions in the frequency domain and their impulse responses in the time domain. Real-time implementations of such linear signal processing filters in the time domain are inevitably causal, an additional constraint on their transfer functions. An analog electronic circuit consisting only of linear components (resistors, capacitors, inductors, and linear amplifiers) will necessarily fall in this category, as will comparable mechanical systems or digital signal processing systems containing only linear elements. Since linear time-invariant filters can be completely characterized by their response to sinusoids of different frequencies (their frequency response), they are sometimes known as frequency filters.
Non real-time implementations of linear time-invariant filters need not be causal. Filters of more than one dimension are also used such as in image processing. The general concept of linear filtering also extends into other fields and technologies such as statistics, data analysis, and mechanical engineering.
## Impulse response and transfer function {#impulse_response_and_transfer_function}
A linear time-invariant (LTI) filter can be uniquely specified by its impulse response *h*, and the output of any filter is mathematically expressed as the convolution of the input with that impulse response. The frequency response, given by the filter\'s transfer function $H(\omega)$, is an alternative characterization of the filter. Typical filter design goals are to realize a particular frequency response, that is, the magnitude of the transfer function $|H(\omega)|$; the importance of the phase of the transfer function varies according to the application, inasmuch as the shape of a waveform can be distorted to a greater or lesser extent in the process of achieving a desired (amplitude) response in the frequency domain. The frequency response may be tailored to, for instance, eliminate unwanted frequency components from an input signal, or to limit an amplifier to signals within a particular band of frequencies.
The impulse response *h* of a linear time-invariant causal filter specifies the output that the filter would produce if it were to receive an input consisting of a single impulse at time 0. An \"impulse\" in a continuous time filter means a Dirac delta function; in a discrete time filter the Kronecker delta function would apply. The impulse response completely characterizes the response of any such filter, inasmuch as any possible input signal can be expressed as a (possibly infinite) combination of weighted delta functions. Multiplying the impulse response shifted in time according to the arrival of each of these delta functions by the amplitude of each delta function, and summing these responses together (according to the superposition principle, applicable to all linear systems) yields the output waveform.
Mathematically this is described as the convolution of a time-varying input signal *x(t)* with the filter\'s impulse response *h*, defined as:
$$y(t) = \int_{0}^{T} x(t-\tau)\, h(\tau)\, d\tau$$ or
$$y_k = \sum_{i=0}^{N} x_{k-i}\, h_i$$.
The first form is the continuous-time form, which describes mechanical and analog electronic systems, for instance. The second equation is a discrete-time version used, for example, by digital filters implemented in software, so-called *digital signal processing*. The impulse response *h* completely characterizes any linear time-invariant (or shift-invariant in the discrete-time case) filter. The input *x* is said to be \"convolved\" with the impulse response *h* having a (possibly infinite) duration of time *T* (or of *N* sampling periods).
Filter design consists of finding a possible transfer function that can be implemented within certain practical constraints dictated by the technology or desired complexity of the system, followed by a practical design that realizes that transfer function using the chosen technology. The complexity of a filter may be specified according to the order of the filter.
Among the time-domain filters we here consider, there are two general classes of filter transfer functions that can approximate a desired frequency response. Very different mathematical treatments apply to the design of filters termed infinite impulse response (IIR) filters, characteristic of mechanical and analog electronics systems, and finite impulse response (FIR) filters, which can be implemented by discrete time systems such as computers (then termed *digital signal processing*).
### Implementation issues {#implementation_issues}
Classical analog filters are IIR filters, and classical filter theory centers on the determination of transfer functions given by low order rational functions, which can be synthesized using the same small number of reactive components. Using digital computers, on the other hand, both FIR and IIR filters are straightforward to implement in software.
A digital IIR filter can generally approximate a desired filter response using less computing power than a FIR filter, however this advantage is more often unneeded given the increasing power of digital processors. The ease of designing and characterizing FIR filters makes them preferable to the filter designer (programmer) when ample computing power is available. Another advantage of FIR filters is that their impulse response can be made symmetric, which implies a response in the frequency domain that has zero phase at all frequencies (not considering a finite delay), which is absolutely impossible with any IIR filter.
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# Linear filter
## Frequency response {#frequency_response}
The frequency response or transfer function $|H(\omega)|$ of a filter can be obtained if the impulse response is known, or directly through analysis using Laplace transforms, or in discrete-time systems the Z-transform. The frequency response also includes the phase as a function of frequency, however in many cases the phase response is of little or no interest. FIR filters can be made to have zero phase, but with IIR filters that is generally impossible. With most IIR transfer functions there are related transfer functions having a frequency response with the same magnitude but a different phase; in most cases the so-called minimum phase transfer function is preferred.
Filters in the time domain are most often requested to follow a specified frequency response. Then, a mathematical procedure finds a filter transfer function that can be realized (within some constraints), and approximates the desired response to within some criterion. Common filter response specifications are described as follows:
- A low-pass filter passes low frequencies while blocking higher frequencies.
- A high-pass filter passes high frequencies.
- A band-pass filter passes a band (range) of frequencies.
- A band-stop filter passes high and low frequencies outside of a specified band.
- A notch filter has a null response at a particular frequency. This function may be combined with one of the above responses.
- An all-pass filter passes all frequencies equally well, but alters the group delay and phase relationship among them.
- An equalization filter is not designed to fully pass or block any frequency, but instead to gradually vary the amplitude response as a function of frequency: filters used as pre-emphasis filters, equalizers, or tone controls are good examples.
### FIR transfer functions {#fir_transfer_functions}
Meeting a frequency response requirement with an FIR filter uses relatively straightforward procedures. In the most basic form, the desired frequency response itself can be sampled with a resolution of $\Delta f$ and Fourier transformed to the time domain. This obtains the filter coefficients *h~i~*, which implements a zero phase FIR filter that matches the frequency response at the sampled frequencies used. To better match a desired response, $\Delta f$ must be reduced. However the duration of the filter\'s impulse response, and the number of terms that must be summed for each output value (according to the above discrete time convolution) is given by $N=1/(\Delta f \, T)$ where *T* is the sampling period of the discrete time system (N-1 is also termed the *order* of an FIR filter). Thus the complexity of a digital filter and the computing time involved, grows inversely with $\Delta f$, placing a higher cost on filter functions that better approximate the desired behavior. For the same reason, filter functions whose critical response is at lower frequencies (compared to the sampling frequency *1/T*) require a higher order, more computationally intensive FIR filter. An IIR filter can thus be much more efficient in such cases.
Elsewhere the reader may find further discussion of design methods for practical FIR filter design.
### IIR transfer functions {#iir_transfer_functions}
Since classical analog filters are IIR filters, there has been a long history of studying the range of possible transfer functions implementing various of the above desired filter responses in continuous time systems. Using transforms it is possible to convert these continuous time frequency responses to ones that are implemented in discrete time, for use in digital IIR filters. The complexity of any such filter is given by the *order* N, which describes the order of the rational function describing the frequency response. The order N is of particular importance in analog filters, because an N^th^ order electronic filter requires N reactive elements (capacitors and/or inductors) to implement. If a filter is implemented using, for instance, biquad stages using op-amps, N/2 stages are needed. In a digital implementation, the number of computations performed per sample is proportional to N. Thus the mathematical problem is to obtain the best approximation (in some sense) to the desired response using a smaller N, as we shall now illustrate.
Below are the frequency responses of several standard filter functions that approximate a desired response, optimized according to some criterion. These are all fifth-order low-pass filters, designed for a cutoff frequency of .5 in normalized units. Frequency responses are shown for the Butterworth, Chebyshev, inverse Chebyshev, and elliptic filters.
As is clear from the image, the elliptic filter is sharper than the others, but at the expense of ripples in both its passband and stopband. The Butterworth filter has the poorest transition but has a more even response, avoiding ripples in either the passband or stopband. A Bessel filter (not shown) has an even poorer transition in the frequency domain, but maintains the best phase fidelity of a waveform. Different applications emphasize different design requirements, leading to different choices among these (and other) optimizations, or requiring a filter of a higher order.
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# Linear filter
## Example implementations {#example_implementations}
A popular circuit implementing a second order active R-C filter is the Sallen-Key design, whose schematic diagram is shown here. This topology can be adapted to produce low-pass, band-pass, and high pass filters.
An N^th^ order FIR filter can be implemented in a discrete time system using a computer program or specialized hardware in which the input signal is subject to N delay stages. The output of the filter is formed as the weighted sum of those delayed signals, as is depicted in the accompanying signal flow diagram. The response of the filter depends on the weighting coefficients denoted *b~0~*, *b~1~*, \.... *b~N~*. For instance, if all of the coefficients were equal to unity, a so-called boxcar function, then it would implement a low-pass filter with a low frequency gain of N+1 and a frequency response given by the sinc function. Superior shapes for the frequency response can be obtained using coefficients derived from a more sophisticated design procedure.
## Mathematics of filter design {#mathematics_of_filter_design}
LTI system theory describes linear *time-invariant* (LTI) filters of all types. LTI filters can be completely described by their frequency response and phase response, the specification of which uniquely defines their impulse response, and *vice versa*. From a mathematical viewpoint, continuous-time IIR LTI filters may be described in terms of linear differential equations, and their impulse responses considered as Green\'s functions of the equation. Continuous-time LTI filters may also be described in terms of the Laplace transform of their impulse response, which allows all of the characteristics of the filter to be analyzed by considering the pattern of zeros and poles of their Laplace transform in the complex plane. Similarly, discrete-time LTI filters may be analyzed via the Z-transform of their impulse response.
Before the advent of computer filter synthesis tools, graphical tools such as Bode plots and Nyquist plots were extensively used as design tools. Even today, they are invaluable tools to understanding filter behavior. Reference books had extensive plots of frequency response, phase response, group delay, and impulse response for various types of filters, of various orders. They also contained tables of values showing how to implement such filters as RLC ladders - very useful when amplifying elements were expensive compared to passive components. Such a ladder can also be designed to have minimal sensitivity to component variation a property hard to evaluate without computer tools.
Many different analog filter designs have been developed, each trying to optimise some feature of the system response. For practical filters, a custom design is sometimes desirable, that can offer the best tradeoff between different design criteria, which may include component count and cost, as well as filter response characteristics.
These descriptions refer to the *mathematical* properties of the filter (that is, the frequency and phase response). These can be *implemented* as analog circuits (for instance, using a Sallen Key filter topology, a type of active filter), or as algorithms in digital signal processing systems.
Digital filters are much more flexible to synthesize and use than analog filters, where the constraints of the design permits their use. Notably, there is no need to consider component tolerances, and very high Q levels may be obtained.
FIR digital filters may be implemented by the direct convolution of the desired impulse response with the input signal. They can easily be designed to give a matched filter for any arbitrary pulse shape.
IIR digital filters are often more difficult to design, due to problems including dynamic range issues, quantization noise and instability. Typically digital IIR filters are designed as a series of digital biquad filters.
All low-pass second-order continuous-time filters have a transfer function given by
: $H(s)=\frac{K \omega^{2}_{0}}{s^{2}+\frac{\omega_{0}}{Q}s+\omega^{2}_{0}}.$
All band-pass second-order continuous-time filters have a transfer function given by
: $H(s)=\frac{K \frac{\omega_{0}}{Q}s}{s^{2}+\frac{\omega_{0}}{Q}s+\omega^{2}_{0}}
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# Ergative case
In grammar, the **ergative case** (abbreviated `{{smallcaps|'''erg'''}}`{=mediawiki}) is the grammatical case that identifies a nominal phrase as the agent of a transitive verb in ergative--absolutive languages.
## Characteristics
In such languages, the ergative case is typically marked (most salient), while the absolutive case is unmarked. Recent work in case theory has vigorously supported the idea that the ergative case identifies the agent (the intentful performer of an action) of a verb.
In Kalaallisut (Greenlandic) for example, the ergative case is used to mark subjects of transitive verbs and possessors of nouns. This syncretism with the genitive is commonly referred to as the *relative* case.
Nez Perce has a three-way nominal case system with both ergative (*-nim*) and accusative (*-ne*) plus an absolute (unmarked) case for intransitive subjects: *hipáayna qíiwn* 'the old man arrived'; *hipáayna wewúkiye* 'the elk arrived'; *wewúkiyene péexne qíiwnim* 'the old man saw an elk'.
Sahaptin has an ergative noun case (with suffix *-nɨm*) that is limited to transitive constructions only when the direct object is 1st or 2nd person: *iwapáatayaaš łmámanɨm* 'the old woman helped me'; *paanáy iwapáataya łmáma* 'the old woman helped him/her' (direct); *páwapaataya łmámayin* 'the old woman helped him/her' (inverse).
In languages with an optional ergative, the choice between marking the ergative case or not depends on semantic or pragmatics aspects such as marking focus on the argument.
Other languages that use the ergative case are Georgian, Chechen, and other Caucasian languages, Mayan languages, Mixe--Zoque languages, Wagiman and other Australian Aboriginal languages as well as Basque, Burushaski and Tibetan. Among all Indo-European languages, only Yaghnobi, Kurdish language varieties (including Kurmanji, Zazaki and Sorani) and Pashto from the Iranian languages and Hindi/Urdu, along with some other Indo-Aryan languages, are ergative.
The ergative case is also a feature of some constructed languages such as Na\'vi, Ithkuil and Black Speech
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# Outline of entertainment
The following outline provides an overview of and topical guide to entertainment and the entertainment industry:
**Entertainment** is any activity which provides a diversion or permits people to amuse themselves in their leisure time, and may also provide fun, enjoyment, and laughter. People may create their own entertainment, such as when they spontaneously invent a game; participate actively in an activity they find entertaining, such as when they play sport as a hobby; or consume an entertainment product passively, such as when they attend a performance.
The **entertainment industry** (informally known as **show business** or **show biz**) is part of the tertiary sector of the economy and includes many sub-industries devoted to entertainment. However, the term is often used in the mass media to describe the mass media companies that control the distribution and manufacture of mass media entertainment. In the popular parlance, the term *show biz* in particular connotes the commercially popular performing arts, especially musical theatre, vaudeville, comedy, film, fun, and music. It applies to every aspect of entertainment including cinema, television, radio, theatre, and music
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# Edda
\"**Edda**\" (`{{IPAc-en|ˈ|ɛ|d|ə}}`{=mediawiki}; Old Norse *Edda*, plural *Eddur*) is an Old Norse term that has been applied by modern scholars to the collective of two Medieval Icelandic literary works: what is now known as the *Prose Edda* and an older collection of poems (without an original title) now known as the *Poetic Edda*. The term historically referred only to the *Prose Edda*, but this usage has fallen out of favour because of confusion with the other work. Both works were recorded in Iceland during the 13th century in Icelandic, although they contain material from earlier traditional sources, reaching back into the Viking Age. The books provide the main sources for medieval skaldic tradition in Iceland and for Norse mythology.
## Etymology
At least five hypotheses have been suggested for the origins of the word *edda*:
- One hypothesis holds that it is identical to a word that means \"great-grandmother\" appearing in the Eddic poem *Rígsþula.*
- Another hypothesis holds that *edda* derives from Old Norse *óðr*, \"poetry\".
- A third, proposed in 1895 by Eiríkr Magnússon, is that it derives from the Icelandic place name *Oddi*, site of the church and school where students, including Snorri Sturluson, were educated.
- A fourth hypothesis---the derivation of the word *Edda* as the name of Snorri Sturluson\'s treatise on poetry from the Latin *edo*, \"I compose (poetry)\", by analogy with *kredda*, \"superstition\", from Latin *credo*, \"creed\"---is now widely accepted, although this acceptance might stem from its agreement with modern usage rather than historical accuracy.
- The fifth hypothesis is based on the past fashion of giving Icelandic manuscripts bird titles. Such are the legal codes *Grágás* \'grey goose\', *Gullfjǫðr* \'gold feather (quill?)\', and *Hryggjar-stykki* \'a kind of duck\'. Perhaps *Edda* was also one of such titles: *Edda* would be an appropriate \'pet name\' of *æðr* (pronounced as \[æ:ðr\] f.) \'eider duck\'. Then, *Edda* meant \'little eider duck\' (an analog of *Grágás*).
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# Edda
## The *Poetic Edda* {#the_poetic_edda}
The *Poetic Edda*, also known as *Sæmundar Edda* or the *Elder Edda*, is a collection of Old Norse poems from the Icelandic medieval manuscript Codex Regius (\"Royal Book\"). Along with the *Prose Edda*, the *Poetic Edda* is the most expansive source on Norse mythology. The first part of the Codex Regius preserves poems that narrate the creation and foretold destruction and rebirth of the Old Norse mythological world as well as individual myths about gods concerning Norse deities. The poems in the second part narrate legends about Norse heroes and heroines, such as Sigurd, Brynhildr and Gunnar.
It consists of two parts. The first part has 10 songs about gods, and the second one has 19 songs about heroes.
The Codex Regius was written in the 13th century, but nothing is known of its whereabouts until 1643, when it came into the possession of Brynjólfur Sveinsson, then the Church of Iceland\'s Bishop of Skálholt. At that time, versions of the *Prose Edda* were well known in Iceland, but scholars speculated that there once was another *Edda*---an *Elder Edda*---which contained the pagan poems Snorri quotes in his book. When the Codex Regius was discovered, it seemed that this speculation had proven correct. Brynjólfur attributed the manuscript to Sæmundr the Learned, a larger-than-life 12th century Icelandic priest. While this attribution is rejected by modern scholars, the name *Sæmundar Edda* is still sometimes encountered.
Bishop Brynjólfur sent the *Codex Regius* as a present to King Christian IV of Denmark, hence the name *Codex Regius*. For centuries it was stored in the Royal Library in Copenhagen but in 1971 it was returned to Iceland.
## The *Prose Edda* {#the_prose_edda}
The *Prose Edda*, sometimes referred to as the *Younger Edda* or *Snorri\'s Edda*, is an Icelandic manual of poetics which also contains many mythological stories. Its purpose was to enable Icelandic poets and readers to understand the subtleties of alliterative verse, and to grasp the mythological allusions behind the many kennings that were used in skaldic poetry.
It was written by the Icelandic scholar and historian Snorri Sturluson around 1220. It survives in four known manuscripts and three fragments, written down from about 1300 to about 1600.
The *Prose Edda* consists of a Prologue and three separate books: *Gylfaginning*, concerning the creation and foretold destruction and rebirth of the Norse mythical world; *Skáldskaparmál*, a dialogue between Ægir, a Norse god connected with the sea, and Bragi, the skaldic god of poetry; and *Háttatal*, a demonstration of verse forms used in Norse mythology
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# Educational essentialism
**Educational essentialism** is an educational philosophy whose adherents believe that children should learn the traditional basic subjects thoroughly. In this philosophical school of thought, the aim is to instill students with the \"essentials\" of academic knowledge, enacting a back-to-basics approach. Essentialism ensures that the accumulated wisdom of our civilization as taught in the traditional academic disciplines is passed on from teacher to student. Such disciplines might include Reading, Writing, Literature, Foreign Languages, History, Mathematics, Classical Languages, Science, Art, and Music. Moreover, this traditional approach is meant to train the mind, promote reasoning, and ensure a common culture.
## Principles of essentialism {#principles_of_essentialism}
Essentialism is a relatively conservative stance to education that strives to teach students the knowledge of a society and civilization through a core curriculum. This core curriculum involves such areas that include; the study of the surrounding environment, basic natural laws, and the disciplines that promote a happier, more educated living. Other non-traditional areas are also integrated as well in moderation to balance the education. Essentialists\' goals are to instill students with the \"essentials\" of academic knowledge, patriotism, and character development through traditional (or back-to-basic) approaches. This is to promote reasoning, train the mind, and ensure a common culture for all citizens.
Essentialism is the most typically enacted philosophy in American classrooms today. Traces of this can be found in the organized learning centered on teachers and textbooks, in addition to the regular assignments and evaluations.
### Essentialism as a teacher-centered philosophy {#essentialism_as_a_teacher_centered_philosophy}
The role of the teacher as the leader of the classroom is a very important tenet of Educational essentialism. The teacher is the center of the classroom, so they should be rigid and disciplinary. Establishing order in the classroom is crucial for student learning; effective teaching cannot take place in a loud and disorganized environment. It is the teacher\'s responsibility to keep order in the classroom. The teacher must interpret essentials of the learning process, take the leadership position and set the tone of the classroom. These needs require an educator who is academically well-qualified with an appreciation for learning and development. The teacher must control the students with distributions of rewards and penalties. It has been argued that recent teacher education policies in some countries extend essentialism to teacher education policy frameworks.
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# Educational essentialism
## History of essentialism {#history_of_essentialism}
The Essentialist movement first began in the United States in the year 1938. In Atlantic City, New Jersey, a group met for the first time called \"The Essentialist\'s Committee for the Advancement of Education.\" Their emphasis was to reform the educational system to a rationality-based system.
The term essentialist first appeared in the book *An Introduction to the Philosophy of Education* which was written by Michael John Demiashkevich. In his book, Demiashkevich labels some specific educators (including William C. Bagley) as "essentialists.\" Demiashkevich compared the essentialists to the different viewpoints of the Progressive Education Association. He described how the Progressives preached a "hedonistic doctrine of change" whereas the essentialists stressed the moral responsibility of man for his actions and looked toward permanent principles of behavior (Demiashkevich likened the arguments to those between the Socratics and the Sophists in Greek philosophy). In 1938 Bagley and other educators met together where Bagley gave a speech detailing the main points of the essentialism movement and attacking the public education in the United States. One point that Bagley noted was that students in the U.S. were not getting an education on the same levels as students in Europe who were the same age.
A recent branch has emerged within the essentialist school of thought called \"neoessentialism.\" Emerging in the eighties as a response to the essentialist ideals of the thirties as well as to the criticism of the fifties and the advocates for education in the seventies, neoessentialism was created to try to appease the problems facing the United States at the time. The most notable change within this school of thought is that it called for the creation of a new discipline, computer science.
### Renowned essentialists {#renowned_essentialists}
William Bagley (1874--1946) was an important historical essentialist. William C. Bagley completed his undergraduate degree at Michigan Agricultural College in 1895. It wasn\'t until after finishing his undergraduate studies that he truly wanted to be a teacher. Bagley did his Graduate studies at the University of Chicago and at Cornell University. He acquired his Ph.D. in 1900, after which he took his first school job as a Principal in a St. Louis, Missouri Elementary School. Bagley\'s devotion increased during his work at Montana State Normal School in Dillon, Montana. It was here where he decided to dedicate his time to the education of teachers and where he published *The Educative Process*, launching his name across the nation. Throughout his career Bagley argued against the conservative position that teachers were not in need of special training for their work. He believed that liberal arts material was important in teacher education. Bagley also believed the dominant theories of education of the time were weak and lacking.
In April 1938, he published the *Essentialist\'s Platform*, in which he outlined three major points of essentialism. He described the right of students to a well-educated and culturally knowledgeable teacher. Secondly, he discussed the importance of teaching the ideals of community to each group of students. Lastly, Bagley wrote of the importance of accuracy, thoroughness and effort on the part of the student in the classroom.
Another important essentialist is E. D. Hirsch (1928-). Hirsch was Founder and Chairman of the Core Knowledge Foundation and authored several books concerning fact-based approaches to education. Now retired, he spent many years teaching at the University of Virginia while also being an advocate for the \"back to basics\" movement. In his most popular book, *Cultural Literacy --- What Every American Needs To Know*, he offers lists, quotations, and information regarding what he believes is essential knowledge.
See also Arthur Bestor.
## Schools enacting an essentialist curriculum {#schools_enacting_an_essentialist_curriculum}
The Core Knowledge Schools were founded on the philosophy of essentialist E.D. Hirsch. Although it is difficult to maintain a pure and strict essentialist-only curriculum, these schools have the central aim of establishing a common knowledge base for all citizens. To do so, they follow a nationwide, content-specific, and teacher-centered curriculum. The Core Knowledge curriculum also allows for local variance above and beyond the core curriculum. Central curricular aims are academic excellence and the learning of knowledge, and teachers who are masters of their knowledge areas serve this aim.
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# Educational essentialism
## Criticism of essentialism {#criticism_of_essentialism}
Because Essentialism is largely teacher-centered, the role of the student is often called into question. Presumably, in an essentialist classroom, the teacher is the one designing the curriculum for the students based upon the core disciplines. Moreover, he or she is enacting the curriculum and setting the standards which the students must meet. The teacher\'s evaluative role may undermine students\' interest in study. As a result, the students begin to take on more of a passive role in their education as they are forced to meet and learn such standards and information.
Furthermore, there is also speculation that an essentialist education helps in promoting the cultural lag. This philosophy of education is very traditional in the mindset of passing on the knowledge of the culture via the academic disciplines. Thus, students are forced to think in the mindset of the larger culture, and individual creativity, and subversive investigation are often not emphasized, or even outright discouraged
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# Progressive education
**Progressive education**, or **educational progressivism**, is a pedagogical movement that began in the late 19th century and has persisted in various forms to the present. In Europe, progressive education took the form of the New Education Movement. The term *progressive* was engaged to distinguish this education from the traditional curricula of the 19th century, which was rooted in classical preparation for the early-industrial university and strongly differentiated by social class. By contrast, progressive education finds its roots in modern, post-industrial experience. Most progressive education programs have these qualities in common: `{{TOC right}}`{=mediawiki}
- Emphasis on learning by doing -- hands-on projects, expeditionary learning, experiential learning
- Integrated curriculum focused on thematic units
- Strong emphasis on problem solving and critical thinking
- Group work and development of social skills
- Understanding and action as the goals of learning as opposed to rote knowledge
- Collaborative and cooperative learning projects
- Education for social responsibility and democracy
- Integration of community service and service learning projects into the daily curriculum
- Selection of subject content by looking forward to ask what skills will be needed in future society
- De-emphasis on textbooks in favor of varied learning resources
- Emphasis on lifelong learning and social skills
- Assessment by evaluation of child\'s projects and productions
## History
Progressive education can be traced back to the works of John Locke and Jean-Jacques Rousseau, both of whom are known as forerunners of ideas that would be developed by theorists such as John Dewey. Considered one of the first of the British empiricists, Locke believed that \"truth and knowledge... arise out of observation and experience rather than manipulation of accepted or given ideas\". He further discussed the need for children to have concrete experiences in order to learn. Rousseau deepened this line of thinking in Emile, or On Education, where he argued that subordination of students to teachers and memorization of facts would not lead to an education.
### Johann Bernhard Basedow {#johann_bernhard_basedow}
In Germany, Johann Bernhard Basedow (1724--1790) established the Philanthropinum at Dessau in 1774. He developed new teaching methods based on conversation and play with the child, and a program of physical development. Such was his success that he wrote a treatise on his methods, \"On the best and hitherto unknown method of teaching children of noblemen\".
### Christian Gotthilf Salzmann {#christian_gotthilf_salzmann}
Christian Gotthilf Salzmann (1744--1811) was the founder of the Schnepfenthal institution, a school dedicated to new modes of education (derived heavily from the ideas of Jean-Jacques Rousseau). He wrote *Elements of Morality, for the Use of Children*, one of the first books translated into English by Mary Wollstonecraft.
### Johann Heinrich Pestalozzi {#johann_heinrich_pestalozzi}
Johann Heinrich Pestalozzi (1746--1827) was a Swiss pedagogue and educational reformer who exemplified Romanticism in his approach. He founded several educational institutions both in German- and French-speaking regions of Switzerland and wrote many works explaining his revolutionary modern principles of education. His motto was \"Learning by head, hand and heart\". His research and theories closely resemble those outlined by Rousseau in Emile. He is further considered by many to be the \"father of modern educational science\" His psychological theories pertain to education as they focus on the development of object teaching, that is, he felt that individuals best learned through experiences and through a direct manipulation and experience of objects. He further speculated that children learn through their own internal motivation rather than through compulsion. (See Intrinsic vs. Extrinsic motivation). A teacher\'s task will be to help guide their students as individuals through their learning and allow it to unfold naturally.
### Friedrich Fröbel {#friedrich_fröbel}
Friedrich Wilhelm August Fröbel (1782--1852) was a student of Pestalozzi who laid the foundation for modern education based on the recognition that children have unique needs and capabilities. He believed in \"self-activity\" and play as essential factors in child education. The teacher\'s role was not to indoctrinate but to encourage self-expression through play, both individually and in group activities. He created the concept of kindergarten.
### Johann Friedrich Herbart {#johann_friedrich_herbart}
Johann Friedrich Herbart (1776--1841) emphasized the connection between individual development and the resulting societal contribution. The five key ideas which composed his concept of individual maturation were Inner Freedom, Perfection, Benevolence, Justice, and Equity or Recompense. According to Herbart, abilities were not innate but could be instilled, so a thorough education could provide the framework for moral and intellectual development. In order to develop a child to lead to a consciousness of social responsibility, Herbart advocated that teachers utilize a methodology with five formal steps: \"Using this structure a teacher prepared a topic of interest to the children, presented that topic, and questioned them inductively, so that they reached new knowledge based on what they had already known, looked back, and deductively summed up the lesson\'s achievements, then related them to moral precepts for daily living\".
### John Melchior Bosco {#john_melchior_bosco}
John Melchior Bosco (1815--1888) was concerned about the education of street children who had left their villages to find work in the rapidly industrialized city of Turin, Italy. Exploited as cheap labor or imprisoned for unruly behavior, Bosco saw the need for creating a space where they would feel at home. He called it an \'Oratory\' where they could play, learn, share friendships, express themselves, develop their creative talents and pick up skills for gainful self-employment. With those who had found work, he set up a mutual-fund society (an early version of the Grameen Bank) to teach them the benefits of saving and self-reliance. The principles underlying his educational method that won over the hearts and minds of thousands of youth who flocked to his oratory were: \'be reasonable\', \'be kind\', \'believe\' and \'be generous in service\'. Today his method of education is practiced in nearly 3000 institutions set up around the world by the members of the Salesian Society he founded in 1873.
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# Progressive education
## History
### Cecil Reddie {#cecil_reddie}
While studying for his doctorate in Göttingen in 1882--1883, Cecil Reddie was greatly impressed by the progressive educational theories being applied there. Reddie founded Abbotsholme School in Derbyshire, England, in 1889. Its curriculum enacted the ideas of progressive education. Reddie rejected rote learning, classical languages and corporal punishment. He combined studies in modern languages and the sciences and arts with a program of physical exercise, manual labour, recreation, crafts and arts. Schools modeling themselves after Abbotsholme were established throughout Europe, and the model was particularly influential in Germany. Reddie often engaged foreign teachers, who learned its practices, before returning home to start their own schools. Hermann Lietz an Abbotsholme teacher founded five schools (Landerziehungsheime für Jungen) on Abbotsholme\'s principles. Other people he influenced included Kurt Hahn, Adolphe Ferrière and Edmond Demolins. His ideas also reached Japan, where it turned into \"Taisho-era Free Education Movement\" (Taisho Jiyu Kyoiku Undo)
### John Dewey {#john_dewey}
Education according to John Dewey is the \"participation of the individual in the social consciousness of the race\" (Dewey, 1897, para. 1). As such, education should take into account that the student is a social being. The process begins at birth with the child unconsciously gaining knowledge and gradually developing their knowledge to share and partake in society.
For Dewey, education, which regulates \"the process of coming to share in the social consciousness,\" is the \"only sure\" method of ensuring social progress and reform (Dewey, 1897, para. 60). In this respect, Dewey foreshadows Social Reconstructionism, whereby schools are a means to reconstruct society. As schools become a means for social reconstruction, they must be given the proper equipment to perform this task and guide their students.
### Helen Parkhurst {#helen_parkhurst}
The American teacher Helen Parkhurst (1886--1973) developed the Dalton Plan at the beginning of the twentieth century with the goal of reforming the then current pedagogy and classroom management. She wanted to break the teacher-centered lockstep teaching. During her first experiment, which she implemented in a small elementary school as a young teacher in 1904, she noticed that when students are given freedom for self-direction and self-pacing and to help one another, their motivation increases considerably and they learn more. In a later experiment in 1911 and 1912, Parkhurst re-organized the education in a large school for nine- to fourteen-year-olds. Instead of each grade, each subject was appointed its own teacher and its own classroom. The subject teachers made assignments: they converted the subject matter for each grade into learning assignments. In this way, learning became the students\' own work; they could carry out their work independently, work at their own pace and plan their work themselves. The classroom turned into a laboratory, a place where students are working, furnished and equipped as work spaces, tailored to meet the requirements of specific subjects. Useful and attractive learning materials, instruments and reference books were put within the students\' reach. The benches were replaced by large tables to facilitate co-operation and group instruction. This second experiment formed the basis for the next experiments, those in Dalton and New York, from 1919 onwards. The only addition was the use of graphs, charts enabling students to keep track of their own progress in each subject.
In the nineteen-twenties and nineteen-thirties, Dalton education spread throughout the world. There is no certainty regarding the exact numbers of Dalton schools, but there was Dalton education in America, Australia, England, Germany, the Netherlands, the Soviet Union, India, China and Japan.
### Rudolf Steiner {#rudolf_steiner}
Rudolf Steiner (1861--1925) first described the principles of what was to become Waldorf education in 1907. He established a series of schools based on these principles beginning in 1919. The focus of the education is on creating a developmentally appropriate curriculum that holistically integrates practical, artistic, social, and academic experiences. There are more than a thousand schools and many more early childhood centers worldwide; it has also become a popular form of homeschooling.
### Maria Montessori {#maria_montessori}
Maria Montessori (1870--1952) began to develop her philosophy and methods in 1897. She based her work on her observations of children and experimentation with the environment, materials, and lessons available to them. She frequently referred to her work as \"scientific pedagogy\", arguing for the need to go beyond observation and measurement of students, to developing new methods to transform them. Although Montessori education spread to the United States in 1911 there were conflicts with the American educational establishment and was opposed by William Heard Kilpatrick. However Montessori education returned to the United States in 1960 and has since spread to thousands of schools there.
In 1914 the Montessori Society in England organised its first conference. Hosted by Rev Bertram Hawker, who had set up, in partnership with his local elementary school in the Norfolk coastal village of East Runton, the first Montessori School in England. Pictures of this school, and its children, illustrated the \'Montessori\'s Own Handbook\' (1914). Hawker had been impressed by his visit to Montessori\'s Casa dei Bambini in Rome, he gave numerous talks on Montessori\'s work after 1912, assisting in generating a national interest in her work. He organised the Montessori Conference 1914 in partnership with Edmond Holmes, ex-Chief Inspector of Schools, who had written a government report on Montessori. The conference decided that its remit was to promote the \'liberation of the child in the school\', and though inspired by Montessori, would encourage, support and network teachers and educationalists who sought, through their schools and methods, that aim. They changed their name the following year to New Ideals in Education. Each subsequent conference was opened with reference to its history and origin as a Montessori Conference recognising her inspiration, reports italicized the members of the Montessori Society in the delegate lists, and numerous further events included Montessori methods and case studies. Montessori, through New Ideals in Education, its committee and members, events and publications, greatly influenced progressive state education in England. (references to be added).
### Robert Baden-Powell {#robert_baden_powell}
In July 1906, Ernest Thompson Seton sent Robert Baden-Powell a copy of his book *The Birchbark Roll of the Woodcraft Indians*. Seton was a British-born Canadian-American living in the United States. They shared ideas about youth training programs. In 1907 Baden-Powell wrote a draft called *Boy Patrols*. In the same year, to test his ideas, he gathered 21 boys of mixed social backgrounds and held a week-long camp in August on Brownsea Island in England. His organizational method, now known as the Patrol System and a key part of Scouting training, allowed the boys to organize themselves into small groups with an elected patrol leader. Baden Powell then wrote *Scouting for Boys* (London, 1908). The Brownsea camp and the publication of *Scouting for Boys* are generally regarded as the start of the Scout movement which spread throughout the world. Baden-Powell and his sister Agnes Baden-Powell introduced the Girl Guides in 1910.
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# Progressive education
## History
### Comparison with traditional education {#comparison_with_traditional_education}
Traditional education uses extrinsic motivation, such as grades and prizes. Progressive education is more likely to use intrinsic motivation, basing activities on the interests of the child. Praise may be discouraged as a motivator. Progressive education is a response to traditional methods of teaching. It is defined as an educational movement which gives more value to experience than formal learning. It is based more on experiential learning that concentrate on the development of a child\'s talents.
### 21st century skills {#st_century_skills}
21st century skills are a series of higher-order skills, abilities, and learning dispositions that have been identified as being required for success in the rapidly changing, digital society and workplaces. Many of these skills are also defining qualities of *progressive education* as well as being associated with deeper learning, which is based on mastering skills such as analytic reasoning, complex problem solving, and teamwork. These skills differ from traditional academic skills in that they are not primarily content knowledge-based. The focus of progressive pedagogies on fostering 21st-century skills may also explain why these schools maintain their appeal, particularly among a segment of highly-educated, middle-class parents.
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# Progressive education
## In the West {#in_the_west}
### Germany
Hermann Lietz founded three Landerziehungsheime (country boarding schools) in 1904 based on Reddie\'s model for boys of different ages. Lietz eventually succeeded in establishing five more Landerziehungsheime. Edith and Paul Geheeb founded Odenwaldschule in Heppenheim in the Odenwald in 1910 using their concept of progressive education, which integrated the work of the head and hand.
### Poland
Janusz Korczak was one notable follower and developer of Pestalozzi\'s ideas. He wrote *The names of Pestalozzi, Froebel and Spencer shine with no less brilliance than the names of the greatest inventors of the twentieth century. For they discovered more than the unknown forces of nature; they discovered the unknown half of humanity: children.* His Orphan\'s Home in Warsaw became a model institution and exerted influence on the educational process in other orphanages of the same type.
### Ireland
The Quaker school run in **Ballitore**, Co Kildare in the 18th century had students from as far away as Bordeaux (where there was a substantial Irish émigré population), the Caribbean and Norway. Notable pupils included Edmund Burke and Napper Tandy. **Sgoil Éanna**, or in English St Enda\'s was founded in 1908 by Pádraig Pearse on Montessori principles. Its former assistant headmaster Thomas MacDonagh and other teachers including Pearse; games master Con Colbert; Pearse\'s brother, Willie, the art teacher, and Joseph Plunkett, and occasional lecturer in English, were executed by the British after the 1916 Rising. Pearse and MacDonagh were two of the seven leaders who signed the Irish Declaration of Independence. Pearse\'s book *The Murder Machine* was a denunciation of the English school system of the time and a declaration of his own educational principles. Apart from these examples of progressive education, however, during the decades after the advent of national independence in 1922, Irish educational policy makers generally rejected progressive ideas, focusing instead on curricula and teaching methods that reflected the new country\'s Catholic heritage and nationalist ethos up until the 1960s.
### Sweden
In Sweden, an early proponent of progressive education was Alva Myrdal, who with her husband Gunnar co-wrote *Kris i befolkningsfrågan* (1934), a most influential program for the social-democratic hegemony (1932--1976) popularly known as \"Folkhemmet\". School reforms went through government reports in the 1940s and trials in the 1950s, resulting in the introduction in 1962 of public comprehensive schools (\"grundskola\") instead of the previously separated parallel schools for theoretical and non-theoretical education.
### United Kingdom {#united_kingdom}
The ideas from Reddie\'s Abbotsholme spread to schools such as Bedales School (1893), King Alfred School, London (1898) and St Christopher School, Letchworth (1915), as well as all the Friends\' schools, Steiner Waldorf schools and those belonging to the Round Square Conference. The King Alfred School was radical for its time in that it provided a secular education and that boys and girls were educated together. Alexander Sutherland Neill believed children should achieve self-determination and should be encouraged to think critically rather than blindly obeying. He implemented his ideas with the founding of Summerhill School in 1921. Neill believed that children learn better when they are not compelled to attend lessons. The school was also managed democratically, with regular meetings to determine school rules. Pupils had equal voting rights with school staff.
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# Progressive education
## In the West {#in_the_west}
### United States {#united_states}
#### Early practitioners {#early_practitioners}
Fröbel\'s student Margarethe Schurz founded the first kindergarten in the United States at Watertown, Wisconsin, in 1856, and she also inspired Elizabeth Peabody, who went on to found the first English-speaking kindergarten in the United States -- the language at Schurz\'s kindergarten had been German, to serve an immigrant community -- in Boston in 1860. This paved the way for the concept\'s spread in the USA. The German émigré Adolph Douai had also founded a kindergarten in Boston in 1859, but was obliged to close it after only a year. By 1866, however, he was founding others in New York City.
William Heard Kilpatrick (1871--1965) was a pupil of Dewey and one of the most effective practitioners of the concept as well as the more adept at proliferating the progressive education movement and spreading word of the works of Dewey. He is especially well known for his \"project method of teaching\". This developed the progressive education notion that students were to be engaged and taught so that their knowledge may be directed to society for a socially useful need. Like Dewey he also felt that students should be actively engaged in their learning rather than actively disengaged with the simple reading and regurgitation of material.
The most famous early practitioner of progressive education was Francis Parker; its best-known spokesperson was the philosopher John Dewey. In 1875 Francis Parker became superintendent of schools in Quincy, Massachusetts, after spending two years in Germany studying emerging educational trends on the continent. Parker was opposed to rote learning, believing that there was no value in knowledge without understanding. He argued instead schools should encourage and respect the child\'s creativity. Parker\'s Quincy System called for child-centered and experience-based learning. He replaced the traditional curriculum with integrated learning units based on core themes related to the knowledge of different disciplines. He replaced traditional readers, spellers and grammar books with children\'s own writing, literature, and teacher prepared materials. In 1883 Parker left Massachusetts to become Principal of the Cook County Normal School in Chicago, a school that also served to train teachers in Parker\'s methods. In 1894 Parker\'s Talks on Pedagogics, which drew heavily on the thinking of Fröbel, Pestalozzi and Herbart, became one of the first American writings on education to gain international fame.
That same year, philosopher John Dewey moved from the University of Michigan to the newly established University of Chicago where he became chair of the department of philosophy, psychology and education. He and his wife enrolled their children in Parker\'s school before founding their own school two years later.
Whereas Parker started with practice and then moved to theory, Dewey began with hypotheses and then devised methods and curricula to test them. By the time Dewey moved to Chicago at the age of thirty-five, he had already published two books on psychology and applied psychology. He had become dissatisfied with philosophy as pure speculation and was seeking ways to make philosophy directly relevant to practical issues. Moving away from an early interest in Hegel, Dewey proceeded to reject all forms of dualism and dichotomy in favor of a philosophy of experience as a series of unified wholes in which everything can be ultimately related.
In 1896, John Dewey opened what he called the laboratory school to test his theories and their sociological implications. With Dewey as the director and his wife as principal, the University of Chicago Laboratory school, was dedicated \"to discover in administration, selection of subject-matter, methods of learning, teaching, and discipline, how a school could become a cooperative community while developing in individuals their own capacities and satisfy their own needs.\" (Cremin, 136) For Dewey the two key goals of developing a cooperative community and developing individuals\' own capacities were not at odds; they were necessary to each other. This unity of purpose lies at the heart of the progressive education philosophy. In 1912, Dewey sent out students of his philosophy to found The Park School of Buffalo and The Park School of Baltimore to put it into practice. These schools operate to this day within a similar progressive approach.
At Columbia, Dewey worked with other educators such as Charles Eliot and Abraham Flexner to help bring progressivism into the mainstream of American education. In 1917 Columbia established the Lincoln School of Teachers College \"as a laboratory for the working out of an elementary and secondary curriculum which shall eliminate obsolete material and endeavor to work up in usable form material adapted to the needs of modern living.\" (Cremin, 282) Based on Flexner\'s demand that the modern curriculum \"include nothing for which an affirmative case can not be made out\" (Cremin, 281) the new school organized its activities around four fundamental fields: science, industry, aesthetics and civics. The Lincoln School built its curriculum around \"units of work\" that reorganized traditional subject matter into forms embracing the development of children and the changing needs of adult life. The first and second grades carried on a study of community life in which they actually built a city. A third grade project growing out of the day-to-day life of the nearby Hudson River became one of the most celebrated units of the school, a unit on boats, which under the guidance of its legendary teacher Miss Curtis, became an entrée into history, geography, reading, writing, arithmetic, science, art and literature. Each of the units was broadly enough conceived so that different children could concentrate on different aspects depending on their own interests and needs. Each of the units called for widely diverse student activities, and each sought to deal in depth with some critical aspect of contemporary civilization. Finally each unit engaged children working together cooperatively and also provided opportunities for individual research and exploration.
In 1924, Agnes de Lima, the lead writer on education for *The New Republic* and *The Nation*, published a collection of her articles on progressive education as a book, titled *Our Enemy the Child*.
In 1918, the National Education Association, representing superintendents and administrators in smaller districts across the country, issued its report \"Cardinal Principles of Secondary Education.\" It emphasized the education of students in terms of health, a command of fundamental processes, worthy home membership, vocation, citizenship, worthy use of leisure, and ethical character. They emphasized life adjustment and reflected the social efficiency model of progressive education.
From 1919 to 1955, the Progressive Education Association founded by Stanwood Cobb and others worked to promote a more student-centered approach to education. During the Great Depression the organization conducted the Eight-Year Study, evaluating the effects of progressive programs. More than 1500 students over four years were compared to an equal number of carefully matched students at conventional schools. When they reached college, the experimental students were found to equal or surpass traditionally educated students on all outcomes: grades, extracurricular participation, dropout rates, intellectual curiosity, and resourcefulness. Moreover, the study found that the more the school departed from the traditional college preparatory program, the better was the record of the graduates. (Kohn, Schools, 232)
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# Progressive education
## In the West {#in_the_west}
### United States {#united_states}
#### Early practitioners {#early_practitioners}
By mid-century, many public school programs had also adopted elements of progressive curriculum. At mid-century Dewey believed that progressive education had \"not really penetrated and permeated the foundations of the educational institution.\"(Kohn, Schools, 6,7) As the influence of progressive pedagogy grew broader and more diffuse, practitioners began to vary their application of progressive principles. As varying interpretations and practices made evaluation of progressive reforms more difficult to assess, critics began to propose alternative approaches.
The seeds of the debate over progressive education can be seen in the differences of Parker and Dewey. These have to do with how much and by whom curriculum should be worked out from grade to grade, how much the child\'s emerging interests should determine classroom activities, the importance of child-centered vs. societal--centered learning, the relationship of community building to individual growth, and especially the relationship between emotion, thought and experience.
In 1955, the publication of Rudolf Flesch\'s *Why Johnny Can\'t Read* leveled criticism of reading programs at the progressive emphasis on reading in context. The conservative McCarthy era raised questions about the liberal ideas at the roots of the progressive reforms. The launching of Sputnik in 1957 at the height of the Cold War gave rise to a number of intellectually competitive approaches to disciplinary knowledge, such as BSCS biology PSSC physics, led by university professors such as Jerome Bruner and Jerrold Zacharias.
Some Cold War reforms incorporated elements of progressivism. For example, the work of Zacharias and Bruner was based in the developmental psychology of Jean Piaget and incorporated many of Dewey\'s ideas of experiential education. Bruner\'s analysis of developmental psychology became the core of a pedagogical movement known as constructivism, which argues that the child is an active participant in making meaning and must be engaged in the progress of education for learning to be effective. This psychological approach has deep connections to the work of both Parker and Dewey and led to a resurgence of their ideas in second half of the century.
In 1965, President Johnson inaugurated the Great Society and the Elementary and Secondary Education Act suffused public school programs with funds for sweeping education reforms. At the same time the influx of federal funding also gave rise to demands for accountability and the behavioral objectives approach of Robert F. Mager and others foreshadowed the No Child Left Behind Act passed in 2002. Against these critics eloquent spokespersons stepped forward in defense of the progressive tradition. The Open Classroom movement, led by Herb Kohl and George Dennison, recalled many of Parker\'s child centered reforms.
The late 1960s and early 1970s saw a rise and decline in the number of progressive schools. There were several reasons for the decline:
- Demographics: As the baby boom passed, traditional classrooms were no longer as over-enrolled, reducing demand for alternatives.
- The economy: The oil crisis and recession made shoestring schools`{{Definition needed|date=January 2024}}`{=mediawiki} less viable.
- Times changed: With the ending of the Vietnam War, social activism waned.
- Co-optation: Many schools were co-opted by people who didn\'t believe in the original mission.
- Centralization: The ongoing centralization of school districts
- Non-implementation: Schools failed to implement a model of shared governance
- Interpersonal dynamics: Disagreement over school goals, poor group process skills, lack of critical dialogue, and fear of assertive leadership
Progressive education has been viewed as an alternative to the test-oriented instruction legislated by the No Child Left Behind educational funding act. Alfie Kohn has been an outspoken critic of the No Child Left Behind Act and a passionate defender of the progressive tradition.
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# Progressive education
## In the East {#in_the_east}
### India
Rabindranath Tagore (1861--1941) was one of the most effective practitioners of the concept of [progressive education](https://www.mitvpu.ac.in/). He expanded Santiniketan, which is a small town near Bolpur in the Birbhum district of West Bengal, India, approximately 160 km north of Kolkata. He de-emphasized textbook learning in favor of varied learning resources from nature. The emphasis here was on self-motivation rather than on discipline, and on fostering intellectual curiosity rather than competitive excellence. There were courses on a great variety of cultures, and study programs devoted to China, Japan, and the Middle East. He was of the view that education should be a \"joyous exercise of our inventive and constructive energies that help us to build up character.\"
### Japan
Seikatsu Tsuzurikata is a grassroots movement in Japan that has many parallels to the progressive education movement, but it developed completely independently, beginning in the late 1920s. The Japanese progressive educational movement was one of the stepping stones to the modernization of Japan and it has resonated down to the present
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# Electrode
thumb\|upright=1.3\|Electrodes used in shielded metal arc welding `{{wikt | electrode}}`{=mediawiki}
An **electrode** is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a variety of materials (chemicals) depending on the type of cell. An electrode may be called either a cathode or anode according to the direction of the electric current, unrelated to the potential difference between electrodes.
Michael Faraday coined the term \"`{{linktext|electrode}}`{=mediawiki}\" in 1833; the word recalls the Greek ἤλεκτρον (*ḗlektron*, \"amber\") and ὁδός (*hodós*, \"path, way\").
The electrophore, invented by Johan Wilcke in 1762, was an early version of an electrode used to study static electricity.
## Anode and cathode in electrochemical cells {#anode_and_cathode_in_electrochemical_cells}
Electrodes are an essential part of any battery. The first electrochemical battery was devised by Alessandro Volta and was aptly named the Voltaic cell. This battery consisted of a stack of copper and zinc electrodes separated by brine-soaked paper disks. Due to fluctuation in the voltage provided by the voltaic cell, it was not very practical. The first practical battery was invented in 1839 and named the Daniell cell after John Frederic Daniell. It still made use of the zinc--copper electrode combination. Since then, many more batteries have been developed using various materials. The basis of all these is still using two electrodes, anodes and cathodes.
### Anode
\'Anode\' was coined by William Whewell at Michael Faraday\'s request, derived from the Greek words ἄνο (ano), \'upwards\' and ὁδός (hodós), \'a way\'. The anode is the electrode through which the conventional current enters from the electrical circuit of an electrochemical cell (battery) into the non-metallic cell. The electrons then flow to the other side of the battery. Benjamin Franklin surmised that the electrical flow moved from positive to negative. The electrons flow away from the anode and the conventional current towards it. From both can be concluded that the electric potential of the anode is negative. The electron entering the anode comes from the oxidation reaction that takes place next to it.
### Cathode
The cathode is in many ways the opposite of the anode. The name (also coined by Whewell) comes from the Greek words κάτω (kato), \'downwards\' and ὁδός (hodós), \'a way\'. It is the positive electrode, meaning the electrons flow from the electrical circuit through the cathode into the non-metallic part of the electrochemical cell. At the cathode, the reduction reaction takes place with the electrons arriving from the wire connected to the cathode and are absorbed by the oxidizing agent.
### Primary cell {#primary_cell}
A primary cell is a battery designed to be used once and then discarded. This is due to the electrochemical reactions taking place at the electrodes in the cell not being reversible. An example of a primary cell is the discardable alkaline battery commonly used in flashlights. Consisting of a zinc anode and a manganese oxide cathode in which ZnO is formed.
The half-reactions are:
: Zn~(s)~ + 2OH^−^~(aq)~ → ZnO~(s)~ + H~2~O~(l)~ + 2e^−^ $\qquad \qquad$ \[*E*^0^~oxidation~ = −1.28 V\]
: 2MnO~2(s)~ + H~2~O~(l)~ + 2e^−^ → Mn~2~O~3(s)~ + 2OH^−^~(aq)~$\qquad$ \[*E*^0^~reduction~ = +0.15 V\]
Overall reaction:
: Zn~(s)~ + 2MnO~2(s)~ `{{eqm}}`{=mediawiki} ZnO~(s)~ + Mn~2~O~3(s)~$\qquad \qquad$ \[*E*^0^~total~ = +1.43 V\]
The ZnO is prone to clumping and will give less efficient discharge if recharged again. It is possible to recharge these batteries but is due to safety concerns advised against by the manufacturer. Other primary cells include zinc--carbon, zinc--chloride, and lithium iron disulfide.
### Secondary cell {#secondary_cell}
Contrary to the primary cell a secondary cell can be recharged. The first was the lead--acid battery, invented in 1859 by French physicist Gaston Planté. This type of battery is still the most widely used in automobiles, among others. The cathode consists of lead dioxide (PbO2) and the anode of solid lead. Other commonly used rechargeable batteries are nickel--cadmium, nickel--metal hydride, and Lithium-ion. The last of which will be explained more thoroughly in this article due to its importance.
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# Electrode
## Marcus\'s theory of electron transfer {#marcuss_theory_of_electron_transfer}
Marcus theory is a theory originally developed by Nobel laureate Rudolph A. Marcus and explains the rate at which an electron can move from one chemical species to another, for this article this can be seen as \'jumping\' from the electrode to a species in the solvent or vice versa. We can represent the problem as calculating the transfer rate for the transfer of an electron from donor to an acceptor
: D + A → D^+^ + A^−^
The potential energy of the system is a function of the translational, rotational, and vibrational coordinates of the reacting species and the molecules of the surrounding medium, collectively called the reaction coordinates. The abscissa the figure to the right represents these. From the classical electron transfer theory, the expression of the reaction rate constant (probability of reaction) can be calculated, if a non-adiabatic process and parabolic potential energy are assumed, by finding the point of intersection (`{{tmath| Q_x }}`{=mediawiki}). One important thing to note, and was noted by Marcus when he came up with the theory, the electron transfer must abide by the law of conservation of energy and the Frank-Condon principle. Doing this and then rearranging this leads to the expression of the free energy activation (`{{tmath| \Delta G^{\dagger} }}`{=mediawiki}) in terms of the overall free energy of the reaction (`{{tmath| \Delta G^{0} }}`{=mediawiki}). $\Delta G^{\dagger} = \frac{1}{4 \lambda} (\Delta G^{0} + \lambda)^{2}$
In which the $\lambda$ is the reorganisation energy. Filling this result in the classically derived Arrhenius equation $k = A\, \exp\left(\frac{- \Delta G^{\dagger}}{kT}\right),$ leads to $k = A\, \exp\left[{\frac {-(\Delta G^{0} + \lambda)^{2}}{4 \lambda k T}}\right] ,$ with *A* being the pre-exponential factor, which is usually experimentally determined, although a semi-classical derivation provides more information as is explained below.
This classically derived result qualitatively reproduced observations of a maximum electron transfer rate under the conditions `{{tmath|1= \Delta G^{\dagger} = \lambda }}`{=mediawiki}. For a more extensive mathematical treatment one could read the paper by Newton. An interpretation of this result and what a closer look at the physical meaning of the $\lambda$ one can read the paper by Marcus.
The situation at hand can be more accurately described by using the displaced harmonic oscillator model, in this model quantum tunneling is allowed. This is needed in order to explain why even at near-zero absolute temperature there are still electron transfers, in contradiction with the classical theory.
Without going into too much detail on how the derivation is done, it rests on using Fermi\'s golden rule from time-dependent perturbation theory with the full Hamiltonian of the system. It is possible to look at the overlap in the wavefunctions of both the reactants and the products (the right and the left side of the chemical reaction) and therefore when their energies are the same and allow for electron transfer. As touched on before this must happen because only then conservation of energy is abided by. Skipping over a few mathematical steps the probability of electron transfer can be calculated (albeit quite difficult) using the following formula $w_{ET}= \frac{|J|^{2}}{\hbar^{2}}\int_{-\infty}^{+\infty}dt\, e^{-i \Delta Et / \hbar - g (t)} ,$ with $J$ being the electronic coupling constant describing the interaction between the two states (reactants and products) and $g(t)$ being the line shape function. Taking the classical limit of this expression, meaning `{{tmath| \hbar \omega \ll k T }}`{=mediawiki}, and making some substitution an expression is obtained very similar to the classically derived formula, as expected. $w_{ET} = \frac{|J|^{2}}{\hbar} \sqrt{\frac{\pi}{\lambda k T}}\exp\left[\frac {- ( \Delta E + \lambda )^{2}} {4 \lambda k T}\right]$
The main difference is now the pre-exponential factor has now been described by more physical parameters instead of the experimental factor `{{tmath| A }}`{=mediawiki}. One is once again revered to the sources as listed below for a more in-depth and rigorous mathematical derivation and interpretation.
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# Electrode
## Efficiency
The physical properties of electrodes are mainly determined by the material of the electrode and the topology of the electrode. The properties required depend on the application and therefore there are many kinds of electrodes in circulation. The defining property for a material to be used as an electrode is that it be conductive. Any conducting material such as metals, semiconductors, graphite or conductive polymers can therefore be used as an electrode. Often electrodes consist of a combination of materials, each with a specific task. Typical constituents are the active materials which serve as the particles which oxidate or reduct, conductive agents which improve the conductivity of the electrode and binders which are used to contain the active particles within the electrode. The efficiency of electrochemical cells is judged by a number of properties, important quantities are the self-discharge time, the discharge voltage and the cycle performance. The physical properties of the electrodes play an important role in determining these quantities. Important properties of the electrodes are: the electrical resistivity, the specific heat capacity (*c*~p~), the electrode potential and the hardness. Of course, for technological applications, the cost of the material is also an important factor. The values of these properties at room temperature (*T* = 293 K) for some commonly used materials are listed in the table below.
Properties Lithium (Li) Manganese (Mn) Copper (Cu) Zinc (Zn) Graphite
---------------------------------- -------------- ---------------- ------------- ----------- ----------
Resistivity (Ω⋅m)
Electrode potential (V) −3.02 −1.05 −0.340 −0.760 ---
Hardness (HV) \<5 500 50 30 7--11
Specific heat capacity (J/(g⋅K)) 2.997 0.448 0.385 0.3898 0.707
: Common electrode properties
## Surface effects {#surface_effects}
The surface topology of the electrode plays an important role in determining the efficiency of an electrode. The efficiency of the electrode can be reduced due to contact resistance. To create an efficient electrode it is therefore important to design it such that it minimizes the contact resistance.
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# Electrode
## Manufacturing
The production of electrodes for Li-ion batteries is done in various steps as follows:
1. The various constituents of the electrode are mixed into a solvent to produce an \'electrode slurry\'. This mixture is designed such that it improves the performance of the electrodes. Common components of this mixture are:
- The active electrode particles.
- A binder used to contain the active electrode particles.
- A conductive agent used to improve the conductivity of the electrode.
2. The electrode slurry above is coated onto a conductor, which acts as the current collector in the electrochemical cell. Typical current collectors are copper for the cathode and aluminum for the anode.
3. After the slurry has been applied to the conductor it is dried and then pressed to the required thickness.
### Structure of the electrode {#structure_of_the_electrode}
For a given selection of constituents of the electrode, the final efficiency is determined by the internal structure of the electrode. The important factors in the internal structure in determining the performance of the electrode are:
- Clustering of the active material and the conductive agent. In order for all the components of the slurry to perform their task, they should all be spread out evenly within the electrode.
- An even distribution of the conductive agent over the active material. This makes sure that the conductivity of the electrode is optimal.
- The adherence of the electrode to the current collectors. The adherence makes sure that the electrode does not dissolve into the electrolyte.
- The density of the active material. A balance should be found between the amount of active material, the conductive agent and the binder. Since the active material is the important factor in the electrode, the slurry should be designed such that the density of the active material is as high as possible, without the conductive agent and the binder not functioning properly.
These properties can be influenced in the production of the electrodes in a number of manners. The most important step in the manufacturing of the electrodes is creating the electrode slurry. As can be seen above, the important properties of the electrode all have to do with the even distribution of the components of the electrode. Therefore, it is very important that the electrode slurry be as homogeneous as possible. Multiple procedures have been developed to improve this mixing stage and current research is still being done.
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# Electrode
## Electrodes in lithium-ion batteries {#electrodes_in_lithium_ion_batteries}
A modern application of electrodes is in lithium-ion batteries (Li-ion batteries). A Li-ion battery is a kind of flow battery which can be seen in the image on the right.
alt=Redox Flow Battery\|thumb\|upright=1.5\|A typical flow battery consists of two tanks of liquids which are pumped past a membrane held between two electrodes.
Furthermore, a Li-ion battery is an example of a secondary cell since it is rechargeable. It can both act as a galvanic or electrolytic cell. Li-ion batteries use lithium ions as the solute in the electrolyte which are dissolved in an organic solvent. Lithium electrodes were first studied by Gilbert N. Lewis and Frederick G. Keyes in 1913. In the following century these electrodes were used to create and study the first Li-ion batteries. Li-ion batteries are very popular due to their great performance. Applications include mobile phones and electric cars. Due to their popularity, much research is being done to reduce the cost and increase the safety of Li-ion batteries. An integral part of the Li-ion batteries are their anodes and cathodes, therefore much research is being done into increasing the efficiency, safety and reducing the costs of these electrodes specifically.
### Cathodes
In Li-ion batteries, the cathode consists of a intercalated lithium compound (a layered material consisting of layers of molecules composed of lithium and other elements). A common element which makes up part of the molecules in the compound is cobalt. Another frequently used element is manganese. The best choice of compound usually depends on the application of the battery. Advantages for cobalt-based compounds over manganese-based compounds are their high specific heat capacity, high volumetric heat capacity, low self-discharge rate, high discharge voltage and high cycle durability. There are however also drawbacks in using cobalt-based compounds such as their high cost and their low thermostability. Manganese has similar advantages and a lower cost, however there are some problems associated with using manganese. The main problem is that manganese tends to dissolve into the electrolyte over time. For this reason, cobalt is still the most common element which is used in the lithium compounds. There is much research being done into finding new materials which can be used to create cheaper and longer lasting Li-ion batteries For example, Chinese and American researchers have demonstrated that ultralong single wall carbon nanotubes significantly enhance lithium iron phosphate cathodes. By creating a highly efficient conductive network that securely binds lithium iron phosphate particles, adding carbon nanotubes as a conductive additive at a dosage of just 0.5% by weight helps cathodes to achieve a remarkable rate capacity of 161.5 mA⋅h⋅g^−1^ at 0.5 C and 130.2 mA⋅h⋅g^−1^ at 5 C, whole maintaining 87.4% capacity retention after 200 cycles at 2 C.
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# Electrode
## Electrodes in lithium-ion batteries {#electrodes_in_lithium_ion_batteries}
### Anodes
The anodes used in mass-produced Li-ion batteries are either carbon based (usually graphite) or made out of spinel lithium titanate (Li~4~Ti~5~O~12~). Graphite anodes have been successfully implemented in many modern commercially available batteries due to its cheap price, longevity and high energy density. However, it presents issues of dendrite growth, with risks of shorting the battery and posing a safety issue. Li~4~Ti~5~O~12~ has the second largest market share of anodes, due to its stability and good rate capability, but with challenges such as low capacity. During the early 2000s, silicon anode research began picking up pace, becoming one of the decade\'s most promising candidates for future lithium-ion battery anodes. Silicon has one of the highest gravimetric capacities when compared to graphite and Li~4~Ti~5~O~12~ as well as a high volumetric one. Furthermore, Silicon has the advantage of operating under a reasonable open circuit voltage without parasitic lithium reactions. However, silicon anodes have a major issue of volumetric expansion during lithiation of around 360%. This expansion may pulverize the anode, resulting in poor performance. To fix this problem, scientists looked into varying the dimensionality of the Si. Many studies have been developed in Si nanowires, Si tubes as well as Si sheets. As a result, composite hierarchical Si anodes have become the major technology for future applications in lithium-ion batteries. In the early 2020s, technology is reaching commercial levels with factories being built for mass production of anodes in the United States. Furthermore, metallic lithium is another possible candidate for the anode. It boasts a higher specific capacity than silicon, however, does come with the drawback of working with the highly unstable metallic lithium. Similarly to graphite anodes, dendrite formation is another major limitation of metallic lithium, with the solid electrolyte interphase being a major design challenge. In the end, if stabilized, metallic lithium would be able to produce batteries that hold the most charge, while being the lightest. In recent years, researchers have conducted several studies on the use of single wall carbon nanotubes (SWCNTs) as conductive additives. These SWCNTs help to preserve electron conduction, ensure stable electrochemical reactions, and maintain uniform volume changes during cycling, effectively reducing anode pulverization.
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# Electrode
## Electrodes in lithium-ion batteries {#electrodes_in_lithium_ion_batteries}
### Mechanical properties {#mechanical_properties}
A common failure mechanism of batteries is mechanical shock, which breaks either the electrode or the system\'s container, leading to poor conductivity and electrolyte leakage. However, the relevance of mechanical properties of electrodes goes beyond the resistance to collisions due to its environment. During standard operation, the incorporation of ions into electrodes leads to a change in volume. This is well exemplified by Si electrodes in lithium-ion batteries expanding around 300% during lithiation. Such change may lead to the deformations in the lattice and, therefore stresses in the material. The origin of stresses may be due to geometric constraints in the electrode or inhomogeneous plating of the ion. This phenomenon is very concerning as it may lead to electrode fracture and performance loss. Thus, mechanical properties are crucial to enable the development of new electrodes for long lasting batteries. A possible strategy for measuring the mechanical behavior of electrodes during operation is by using nanoindentation. The method is able to analyze how the stresses evolve during the electrochemical reactions, being a valuable tool in evaluating possible pathways for coupling mechanical behavior and electrochemistry.
More than just affecting the electrode\'s morphology, stresses are also able to impact electrochemical reactions. While the chemical driving forces are usually higher in magnitude than the mechanical energies, this is not true for Li-ion batteries. A study by Dr. Larché established a direct relation between the applied stress and the chemical potential of the electrode. Though it neglects multiple variables such as the variation of elastic constraints, it subtracts from the total chemical potential the elastic energy induced by the stress. $\mu = \mu^\text{o} + k\cdot T\cdot\log (\gamma\cdot x) + \Omega \cdot \sigma$
In this equation, *μ* represents the chemical potential, with *μ*^o^ being its reference value. *T* stands for the temperature and *k* the Boltzmann constant. The term *γ* inside the logarithm is the activity and *x* is the ratio of the ion to the total composition of the electrode. The novel term Ω is the partial molar volume of the ion in the host and *σ* corresponds to the mean stress felt by the system. The result of this equation is that diffusion, which is dependent on chemical potential, gets impacted by the added stress and, therefore changes the battery\'s performance. Furthermore, mechanical stresses may also impact the electrode\'s solid-electrolyte-interphase layer. The interface which regulates the ion and charge transfer and can be degraded by stress. Thus, more ions in the solution will be consumed to reform it, diminishing the overall efficiency of the system.
## Other anodes and cathodes {#other_anodes_and_cathodes}
In a vacuum tube or a semiconductor having polarity (diodes, electrolytic capacitors) the anode is the positive (+) electrode and the cathode the negative (−). The electrons enter the device through the cathode and exit the device through the anode. Many devices have other electrodes to control operation, e.g., base, gate, control grid.
In a three-electrode cell, a counter electrode, also called an auxiliary electrode, is used only to make a connection to the electrolyte so that a current can be applied to the working electrode. The counter electrode is usually made of an inert material, such as a noble metal or graphite, to keep it from dissolving.
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# Electrode
## Welding electrodes {#welding_electrodes}
In arc welding, an electrode is used to conduct current through a workpiece to fuse two pieces together. Depending upon the process, the electrode is either consumable, in the case of gas metal arc welding or shielded metal arc welding, or non-consumable, such as in gas tungsten arc welding. For a direct current system, the weld rod or stick may be a cathode for a filling type weld or an anode for other welding processes. For an alternating current arc welder, the welding electrode would not be considered an anode or cathode.
## Alternating current electrodes {#alternating_current_electrodes}
For electrical systems which use alternating current, the electrodes are the connections from the circuitry to the object to be acted upon by the electric current but are not designated anode or cathode because the direction of flow of the electrons changes periodically, usually many times per second.
## Chemically modified electrodes {#chemically_modified_electrodes}
Chemically modified electrodes are electrodes that have their surfaces chemically modified to change the electrode\'s physical, chemical, electrochemical, optical, electrical, and transportive properties. These electrodes are used for advanced purposes in research and investigation.
## Uses
Electrodes are used to provide current through nonmetal objects to alter them in numerous ways and to measure conductivity for numerous purposes
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# Timeline of the evolutionary history of life
The **timeline of the evolutionary history of life** represents the current scientific theory outlining the major events during the development of life on planet Earth. Dates in this article are consensus estimates based on scientific evidence, mainly fossils.
In biology, evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organization, from kingdoms to species, and individual organisms and molecules, such as DNA and proteins. The similarities between all present day organisms imply a common ancestor from which all known species, living and extinct, have diverged. More than 99 percent of all species that ever lived (over five billion) are estimated to be extinct. Estimates on the number of Earth\'s current species range from 10 million to 14 million, with about 1.2 million or 14% documented, the rest not yet described. However, a 2016 report estimates an additional 1 trillion microbial species, with only 0.001% described.
There has been controversy between more traditional views of steadily increasing biodiversity, and a newer view of cycles of annihilation and diversification, so that certain past times, such as the Cambrian explosion, experienced maximums of diversity followed by sharp winnowing.
## Extinction
Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. At long irregular intervals, Earth\'s biosphere suffers a catastrophic die-off, a mass extinction, often comprising an accumulation of smaller extinction events over a relatively brief period.
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet\'s obligate anaerobes. Researchers have identified five other major extinction events in Earth\'s history, with estimated losses below:
- End Ordovician: 440 million years ago, 86% of all species lost, including most graptolites
- Late Devonian: 375 million years ago, 75% of species lost, including most trilobites
- End Permian, The Great Dying: 251 million years ago, 96% of species lost, including tabulate corals, and most trees and synapsids
- End Triassic: 200 million years ago, 80% of species lost, including all conodonts
- End Cretaceous: 66 million years ago, 76% of species lost, including all ammonites, mosasaurs, plesiosaurs, pterosaurs, and nonavian dinosaurs
Smaller extinction events have occurred in the periods between, with some dividing geologic time periods and epochs. The Holocene extinction event is currently under way.
Factors in mass extinctions include continental drift, changes in atmospheric and marine chemistry, volcanism and other aspects of mountain formation, changes in glaciation, changes in sea level, and impact events.
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# Timeline of the evolutionary history of life
## Detailed timeline {#detailed_timeline}
In this timeline, **Ma** (for *megaannum*) means \"million years ago,\" **ka** (for *kiloannum*) means \"thousand years ago,\" and **ya** means \"years ago.\"
### Hadean Eon {#hadean_eon}
*Main article: Hadean* 4540 Ma -- 4031 Ma
Date Event
---------------------------------------------- --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
align=\"RIGHT\" nowrap \| 4540 Ma Planet Earth forms from the accretion disc revolving around the young Sun, perhaps preceded by formation of organic compounds necessary for life in the surrounding protoplanetary disk of cosmic dust.
align=\"RIGHT\" nowrap \| 4510 Ma According to the giant-impact hypothesis, the Moon originated when Earth and the hypothesized planet Theia collided, sending into orbit myriad moonlets which eventually coalesced into our single Moon. The Moon\'s gravitational pull stabilised Earth\'s fluctuating axis of rotation, setting up regular climatic conditions favoring abiogenesis.
align=\"RIGHT\" nowrap \| 4404 Ma Evidence of the first liquid water on Earth which were found in the oldest known zircon crystals.
align=\"RIGHT\" nowrap=\"\" \| 4280--3770 Ma Earliest possible appearance of life on Earth. {{cite news
### Archean Eon {#archean_eon}
4031 Ma -- 2500 Ma
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Date | Event |
+=========================================+======================================================================================================================================================================================================================================================================================================================================================================================================================================================================+
| 4100 Ma | Earliest possible preservation of biogenic carbon. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 4100--3800 Ma | Late Heavy Bombardment (LHB): extended barrage by meteoroids impacting the inner planets. Thermal flux from widespread hydrothermal activity during the LHB may have aided abiogenesis and life\'s early diversification. Possible remains of biotic life were found in 4.1 billion-year-old rocks in Western Australia. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 4000 Ma | Formation of a greenstone belt of the Acasta Gneiss of the Slave craton in northwest Canada - the oldest known rock belt. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 3900--2500 Ma | Cells resembling prokaryotes appear. These first organisms are believed to have been chemoautotrophs, using carbon dioxide as a carbon source and oxidizing inorganic materials to extract energy. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 3800 Ma | Formation of a greenstone belt of the Isua complex in western Greenland, whose isotope frequencies suggest the presence of life. The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 3800--3500 Ma | Last universal common ancestor (LUCA): split between bacteria and archaea. |
| | |
| | Bacteria develop primitive photosynthesis, which at first did not produce oxygen. These organisms exploit a proton gradient to generate adenosine triphosphate (ATP), a mechanism used by virtually all subsequent organisms. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 3000 Ma | Photosynthesizing cyanobacteria using water as a reducing agent and producing oxygen as a waste product. Free oxygen initially oxidizes dissolved iron in the oceans, creating iron ore. Oxygen concentration in the atmosphere slowly rises, poisoning many bacteria and eventually triggering the Great Oxygenation Event. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| align=\"RIGHT\" nowrap \| 2800 Ma | Oldest evidence for microbial life on land in the form of organic matter-rich paleosols, ephemeral ponds and alluvial sequences, some bearing microfossils. |
+-----------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
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# Timeline of the evolutionary history of life
## Detailed timeline {#detailed_timeline}
### Proterozoic Eon {#proterozoic_eon}
*Main article: Proterozoic* 2500 Ma -- 539 Ma. Contains the Palaeoproterozoic, Mesoproterozoic and Neoproterozoic eras.
Date Event
--------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
align=\"RIGHT\" nowrap \| 2500 Ma Great Oxidation Event led by cyanobacteria\'s oxygenic photosynthesis. Commencement of plate tectonics with old marine crust dense enough to subduct.
align=\"RIGHT\" nowrap \|2400 Ma Possible land fungi evidence from molecules.
align=\"RIGHT\" nowrap \|2023 Ma Formation of the Vredefort impact structure, one of the largest and oldest verified impact structures on Earth. The crater is estimated to have been between 170-300 km across when it first formed.
align=\"RIGHT\" nowrap \| By 1850 Ma Eukaryotic cells, containing membrane-bound organelles with diverse functions, probably derived from prokaryotes engulfing each other via phagocytosis. (See Symbiogenesis and Endosymbiont). Bacterial viruses (bacteriophages) emerge before or soon after the divergence of the prokaryotic and eukaryotic lineages. Red beds show an oxidising atmosphere, favouring the spread of eukaryotic life.
align=\"RIGHT\" nowrap \| 1500 Ma Volyn biota, a collection of exceptionally well-preserved microfossils with varying morphologies.
align=\"RIGHT\" nowrap \| 1300 Ma Earliest land fungi.
align=\"RIGHT\" nowrap \| By 1200 Ma Meiosis and sexual reproduction in single-celled eukaryotes, possibly even in the common ancestor of all eukaryotes or in the RNA world. Sexual reproduction may have increased the rate of evolution.
align=\'RIGHT\' nowrap \| By 1000 Ma First non-marine eukaryotes move onto land. They were photosynthetic and multicellular, indicating that plants evolved much earlier than originally thought. \|- valign=\"TOP\'
align=\"RIGHT\" nowrap \| 720--630 Ma Possible global glaciation which increased the atmospheric oxygen and decreased carbon dioxide, and was either *caused* by land plant evolution or *resulted* in it. Opinion is divided on whether it increased or decreased biodiversity or the rate of evolution.
align=\"RIGHT\" nowrap \| 600 Ma Accumulation of atmospheric oxygen allows the formation of an ozone layer. Previous land-based life would probably have required other chemicals to attenuate ultraviolet radiation.
align=\"Right\" nowrap \| 580--542 Ma Ediacaran biota, the first large, complex aquatic multicellular organisms.
align=\"RIGHT\" nowrap \| 580--500 Ma Cambrian explosion: most modern animal phyla appear.
align=\"RIGHT\" nowrap \| 550--540 Ma Ctenophora (comb jellies), Porifera (sponges), Anthozoa (corals and sea anemones), *Ikaria wariootia* (an early Bilaterian).
| 368 |
Timeline of the evolutionary history of life
| 2 |
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# Timeline of the evolutionary history of life
## Detailed timeline {#detailed_timeline}
### Phanerozoic Eon {#phanerozoic_eon}
539 Ma -- present
The Phanerozoic Eon (Greek: period of well-displayed life) marks the appearance in the fossil record of abundant, shell-forming and/or trace-making organisms. It is subdivided into three eras, the Paleozoic, Mesozoic and Cenozoic, with major mass extinctions at division points.
#### Palaeozoic Era {#palaeozoic_era}
538.8 Ma -- 251.9 Ma and contains the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods.
Date Event
-------------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
align=\"RIGHT\" nowrap \| 535 Ma Major diversification of living things in the oceans: arthropods (e.g. trilobites, crustaceans), chordates, echinoderms, molluscs, brachiopods, foraminifers and radiolarians, etc.
align=\"RIGHT\" nowrap \| 530 Ma The first known footprints on land date to 530 Ma.
align=\"RIGHT\" nowrap \| 520 Ma Earliest graptolites.
align=\"RIGHT\" nowrap \| 511 Ma Earliest crustaceans.
align=\"RIGHT\" nowrap \| 505 Ma Fossilization of the Burgess Shale
align=\"RIGHT\" nowrap \| 500 Ma Jellyfish have existed since at least this time.
align=\"RIGHT\" nowrap \| 485 Ma First vertebrates with true bones (jawless fishes).
align=\"RIGHT\" nowrap \| 450 Ma First complete conodonts and echinoids appear.
align=\"RIGHT\" nowrap \| 440 Ma First agnathan fishes: Heterostraci, Galeaspida, and Pituriaspida.
align=\"RIGHT\" nowrap \| 420 Ma Earliest ray-finned fishes, trigonotarbid arachnids, and land scorpions.
align=\"RIGHT\" nowrap \| 410 Ma First signs of teeth in fish. Earliest Nautilida, lycophytes, and trimerophytes.
align=\"RIGHT\" nowrap=\"\" \| 488--400 Ma First cephalopods (nautiloids) and chitons.
align=\"RIGHT\" nowrap \| 395 Ma First lichens, stoneworts. Earliest harvestmen, mites, hexapods (springtails) and ammonoids. The earliest known tracks on land named the Zachelmie trackways which are possibly related to icthyostegalians.
align=\"RIGHT\" nowrap \| 375 Ma Tiktaalik, a lobe-finned fish with some anatomical features similar to early tetrapods. It has been suggested to be a transitional species between fish and tetrapods.
align=\"RIGHT\" nowrap \| 365 Ma *Acanthostega* is one of the earliest vertebrates capable of walking.
align=\"RIGHT\" nowrap \| 363 Ma By the start of the Carboniferous Period, the Earth begins to resemble its present state. Insects roamed the land and would soon take to the skies; sharks swam the oceans as top predators, and vegetation covered the land, with seed-bearing plants and forests soon to flourish. Four-limbed tetrapods gradually gain adaptations which will help them occupy a terrestrial life-habit.
align=\"RIGHT\" nowrap \| 360 Ma First crabs and ferns. Land flora dominated by seed ferns. The Xinhang forest grows around this time.
align=\"RIGHT\" nowrap \| 350 Ma First large sharks, ratfishes, and hagfish; first crown tetrapods (with five digits and no fins and scales).
align=\"RIGHT\" nowrap \| 350 Ma Diversification of amphibians.
align=\"RIGHT\" nowrap \| 325-335 Ma First Reptiliomorpha.
align=\"RIGHT\" nowrap \| 330-320 Ma First amniote vertebrates (*Paleothyris*).
align=\"RIGHT\" nowrap \| 320 Ma Synapsids (precursors to mammals) separate from sauropsids (reptiles) in late Carboniferous.
align=\"RIGHT\" nowrap \| 305 Ma The Carboniferous rainforest collapse occurs, causing a minor extinction event, as well as paving the way for amniotes to become dominant over amphibians and seed plants over ferns and lycophytes. First diapsid reptiles (e.g. *Petrolacosaurus*).
align=\"RIGHT\" nowrap \| 280 Ma Earliest beetles, seed plants and conifers diversify while lepidodendrids and sphenopsids decrease. Terrestrial temnospondyl amphibians and pelycosaurs (e.g. *Dimetrodon*) diversify in species.
align=\"RIGHT\" nowrap \| 275 Ma Therapsid synapsids separate from pelycosaur synapsids.
align=\"RIGHT\" nowrap \| 265 Ma Gorgonopsians appear in the fossil record.
align=\"RIGHT\" nowrap \| 251.9--251.4 Ma The Permian--Triassic extinction event eliminates over 90-95% of marine species. Terrestrial organisms were not as seriously affected as the marine biota. This \"clearing of the slate\" may have led to an ensuing diversification, but life on land took 30 million years to completely recover.
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# Timeline of the evolutionary history of life
## Detailed timeline {#detailed_timeline}
### Phanerozoic Eon {#phanerozoic_eon}
#### Mesozoic Era {#mesozoic_era}
From 251.9 Ma to 66 Ma and containing the Triassic, Jurassic and Cretaceous periods.
Date Event
-------------------------------------------------- --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
align=\"RIGHT\" nowrap \|250 Ma Mesozoic marine revolution begins: increasingly well adapted and diverse predators stress sessile marine groups; the \"balance of power\" in the oceans shifts dramatically as some groups of prey adapt more rapidly and effectively than others.
align=\"RIGHT\" nowrap \| 250 Ma *Triadobatrachus massinoti* is the earliest known frog.
align=\"RIGHT\" nowrap \| 248 Ma Sturgeon and paddlefish (Acipenseridae) first appear.
align=\"RIGHT\" nowrap \| 245 Ma Earliest ichthyosaurs
align=\"RIGHT\" nowrap \| 240 Ma Increase in diversity of cynodonts and rhynchosaurs
align=\"RIGHT\" nowrap \| 225 Ma Earliest dinosaurs (prosauropods), first cardiid bivalves, diversity in cycads, bennettitaleans, and conifers. First teleost fishes. First mammals (*Adelobasileus*).
align=\"RIGHT\" nowrap \| 220 Ma Seed-producing Gymnosperm forests dominate the land; herbivores grow to huge sizes to accommodate the large guts necessary to digest the nutrient-poor plants. First flies and turtles (*Odontochelys*). First coelophysoid dinosaurs. First mammals from small-sized cynodonts, which transitioned towards a nocturnal, insectivorous, and endothermic lifestyle.
align=\"RIGHT\" nowrap \|205 Ma Massive Triassic/Jurassic extinction. It wipes out all pseudosuchians except crocodylomorphs, who transitioned to an aquatic habitat, while dinosaurs took over the land and pterosaurs filled the air.
style=\"text-align:RIGHT;\" nowrap=\"\"\| 200 Ma First accepted evidence for viruses infecting eukaryotic cells (the group Geminiviridae). However, viruses are still poorly understood and may have arisen before \"life\" itself, or may be a more recent phenomenon. Major extinctions in terrestrial vertebrates and large amphibians. Earliest examples of armoured dinosaurs.
align=\"RIGHT\" nowrap \| 195 Ma First pterosaurs with specialized feeding (*Dorygnathus*). First sauropod dinosaurs. Diversification in small, ornithischian dinosaurs: heterodontosaurids, fabrosaurids, and scelidosaurids.
align=\"RIGHT\" nowrap \| 190 Ma Pliosauroids appear in the fossil record. First lepidopteran insects (*Archaeolepis*), hermit crabs, modern starfish, irregular echinoids, corbulid bivalves, and tubulipore bryozoans. Extensive development of sponge reefs.
align=\"RIGHT\" nowrap \| 176 Ma First Stegosaurian dinosaurs.
align=\"RIGHT\" nowrap \| 170 Ma Earliest salamanders, newts, cryptoclidids, elasmosaurid plesiosaurs, and cladotherian mammals. Sauropod dinosaurs diversify.
align=\"RIGHT\" nowrap \| 168 Ma First lizards.
align=\"RIGHT\" nowrap \| 165 Ma First rays and glycymeridid bivalves. First vampire squids.
align=\"RIGHT\" nowrap \| 163 Ma Pterodactyloid pterosaurs first appear.
align=\"RIGHT\" nowrap \| 161 Ma Ceratopsian dinosaurs appear in the fossil record (*Yinlong*) and the oldest known eutherian mammal: *Juramaia*.
align=\"RIGHT\" nowrap \| 160 Ma Multituberculate mammals (genus *Rugosodon*) appear in eastern China.
align=\"RIGHT\" nowrap \| 155 Ma First blood-sucking insects (ceratopogonids), rudist bivalves, and cheilostome bryozoans. *Archaeopteryx*, a possible ancestor to the birds, appears in the fossil record, along with triconodontid and symmetrodont mammals. Diversity in stegosaurian and theropod dinosaurs.
align=\"RIGHT\" nowrap \| 131 Ma First pine trees.
align=\"RIGHT\" nowrap \| 140 Ma Orb-weaver spiders appear.
align=\"RIGHT\" nowrap \| 135 Ma Rise of the angiosperms. Some of these flowering plants bear structures that attract insects and other animals to spread pollen; other angiosperms are pollinated by wind or water. This innovation causes a major burst of animal coevolution. First freshwater pelomedusid turtles. Earliest krill.
align=\"RIGHT\" nowrap \| 120 Ma Oldest fossils of heterokonts, including both marine diatoms and silicoflagellates.
align=\"RIGHT\" nowrap \| 115 Ma First monotreme mammals.
align=\"RIGHT\" nowrap \| 114 Ma Earliest bees.
align=\"RIGHT\" nowrap \| 112 Ma *Xiphactinus*, a large predatory fish, appears in the fossil record.
align=\"RIGHT\" nowrap \| 110 Ma First hesperornithes, toothed diving birds. Earliest limopsid, verticordiid, and thyasirid bivalves.
align=\"RIGHT\" nowrap=\"\" \| 100 Ma First ants.
align=\"RIGHT\" nowrap=\"\" \| 100--95 Ma *Spinosaurus* appears in the fossil record.
align=\"RIGHT\" nowrap=\"\" \| 95 Ma First crocodilians evolve.
align=\"RIGHT\" nowrap \| 90 Ma Extinction of ichthyosaurs. Earliest snakes and nuculanid bivalves. Large diversification in angiosperms: magnoliids, rosids, hamamelidids, monocots, and ginger. Earliest examples of ticks. Probable origins of placental mammals (earliest undisputed fossil evidence is 66 Ma).
86--76 Ma Diversification of therian mammals.
align=\"RIGHT\" nowrap \| 70 Ma Multituberculate mammals increase in diversity. First yoldiid bivalves. First possible ungulates (*Protungulatum*).
align=\"RIGHT\" nowrap \| 68--66 Ma *Tyrannosaurus*, the largest terrestrial predator of western North America, appears in the fossil record. First species of *Triceratops.*
| 685 |
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| 4 |
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# Timeline of the evolutionary history of life
## Detailed timeline {#detailed_timeline}
### Phanerozoic Eon {#phanerozoic_eon}
#### Cenozoic Era {#cenozoic_era}
`{{table alignment}}`{=mediawiki}
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Date | Event |
+================================================================================================================================+==============================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================+
| 66 Ma | The Cretaceous--Paleogene extinction event eradicates about half of all animal species, including mosasaurs, pterosaurs, plesiosaurs, ammonites, belemnites, rudist and inoceramid bivalves, most planktic foraminifers, and all of the dinosaurs excluding the birds. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 66 Ma | Rapid dominance of conifers and ginkgos in high latitudes, along with mammals becoming the dominant species. First psammobiid bivalves. Earliest rodents. Rapid diversification in ants. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 63 Ma | Evolution of the creodonts, an important group of meat-eating (carnivorous) mammals. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 62 Ma | Evolution of the first penguins. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 60 Ma | Diversification of large, flightless birds. Earliest true primates,`{{Who|date=January 2019}}`{=mediawiki} along with the first semelid bivalves, edentate, carnivoran and lipotyphlan mammals, and owls. The ancestors of the carnivorous mammals (miacids) were alive. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 59 Ma | Earliest sailfish appear. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 56 Ma | *Gastornis*, a large flightless bird, appears in the fossil record. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 55 Ma | Modern bird groups diversify (first song birds, parrots, loons, swifts, woodpeckers), first whale (*Himalayacetus*), earliest lagomorphs, armadillos, appearance of sirenian, proboscidean mammals in the fossil record. Flowering plants continue to diversify. The ancestor (according to theory) of the species in the genus *Carcharodon*, the early mako shark *Isurus hastalis*, is alive. Ungulates split into artiodactyla and perissodactyla, with some members of the former returning to the sea. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 52 Ma | First bats appear (*Onychonycteris*). |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 50 Ma | Peak diversity of dinoflagellates and nannofossils, increase in diversity of anomalodesmatan and heteroconch bivalves, brontotheres, tapirs, rhinoceroses, and camels appear in the fossil record, diversification of primates. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 40 Ma | Modern-type butterflies and moths appear. Extinction of *Gastornis*. *Basilosaurus*, one of the first of the giant whales, appeared in the fossil record. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 38 Ma | Earliest bears. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 37 Ma | First nimravid (\"false saber-toothed cats\") carnivores --- these species are unrelated to modern-type felines. First alligators and ruminants. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 35 Ma | Grasses diversify from among the monocot angiosperms; grasslands begin to expand. Slight increase in diversity of cold-tolerant ostracods and foraminifers, along with major extinctions of gastropods, reptiles, amphibians, and multituberculate mammals. Many modern mammal groups begin to appear: first glyptodonts, ground sloths, canids, peccaries, and the first eagles and hawks. Diversity in toothed and baleen whales. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 33 Ma | Evolution of the thylacinid marsupials (*Badjcinus*). |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 30 Ma | First balanids and eucalypts, extinction of embrithopod and brontothere mammals, earliest pigs and cats. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 28 Ma | *Paraceratherium* appears in the fossil record, the largest terrestrial mammal that ever lived. First pelicans. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 25 Ma | *Pelagornis sandersi* appears in the fossil record, the largest flying bird that ever lived. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 25 Ma | First deer. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 24 Ma | First pinnipeds. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 23 Ma | Earliest ostriches, trees representative of most major groups of oaks have appeared by now. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 20 Ma | First giraffes, hyenas, and giant anteaters, increase in bird diversity. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 17 Ma | First birds of the genus Corvus (crows). |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 15 Ma | Genus *Mammut* appears in the fossil record, first bovids and kangaroos, diversity in Australian megafauna. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 10 Ma | Grasslands and savannas are established, diversity in insects, especially ants and termites, horses increase in body size and develop high-crowned teeth, major diversification in grassland mammals and snakes. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 9.5 Ma\ | Great American Interchange, where various land and freshwater faunas migrated between North and South America. Armadillos, opossums, hummingbirds Phorusrhacids, Ground Sloths, Glyptodonts, and Meridiungulates traveled to North America, while horses, tapirs, saber-toothed cats, jaguars, bears, coaties, ferrets, otters, skunks and deer entered South America. |
| `{{Dubious |Great American Interchange|reason=Date is too early; it should be more like 2.7 mya|date=March 2020}}`{=mediawiki} | |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 9 Ma | First platypuses. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 6.5 Ma | First hominins (*Sahelanthropus*). |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 6 Ma | Australopithecines diversify (*Orrorin*, *Ardipithecus*). |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 5 Ma | First tree sloths and hippopotami, diversification of grazing herbivores like zebras and elephants, large carnivorous mammals like lions and the genus *Canis*, burrowing rodents, kangaroos, birds, and small carnivores, vultures increase in size, decrease in the number of perissodactyl mammals. Extinction of nimravid carnivores. First leopard seals. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 4.8 Ma | Mammoths appear in the fossil record. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 4.5 Ma | Marine iguanas diverge from land iguanas. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 4 Ma | *Australopithecus* evolves. *Stupendemys* appears in the fossil record as the largest freshwater turtle, first modern elephants, giraffes, zebras, lions, rhinoceros and gazelles appear in the fossil record |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 3.6 Ma | Blue whales grow to modern size. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 3 Ma | Earliest swordfish. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 2.7 Ma | *Paranthropus evolves.* |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 2.5 Ma | Earliest species of *Arctodus* and *Smilodon* evolve. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 2 Ma | First members of genus *Homo*, Homo Habilis, appear in the fossil record. Diversification of conifers in high latitudes. The eventual ancestor of cattle, aurochs (*Bos primigenus*), evolves in India. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 1.7 Ma | Australopithecines go extinct. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 1.2 Ma | Evolution of *Homo antecessor*. The last members of *Paranthropus* die out. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 1.0 Ma | First coyotes. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 810 ka | First wolves |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| | |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 600 ka | Evolution of *Homo heidelbergensis.* |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 400 ka | First polar bears. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 350 ka | Evolution of Neanderthals. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 300 ka | *Gigantopithecus*, a giant relative of the orangutan from Asia dies out. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 250 ka | Anatomically modern humans appear in Africa. Around 50 ka they start colonising the other continents, replacing Neanderthals in Europe and other hominins in Asia. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 70 ka | Genetic bottleneck in humans (Toba catastrophe theory). |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 40 ka | Last giant monitor lizards (Varanus priscus) die out. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 35--25 ka | Extinction of Neanderthals. Domestication of dogs. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 15 ka | Last woolly rhinoceros (*Coelodonta antiquitatis*) are believed to have gone extinct. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 11 ka | Short-faced bears vanish from North America, with the last giant ground sloths dying out. All Equidae become extinct in North America. Domestication of various ungulates. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 10 ka | Holocene epoch starts after the Last Glacial Maximum. Last mainland species of woolly mammoth (*Mammuthus primigenus*) die out, as does the last *Smilodon* species. |
+--------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 8 ka | The giant lemur dies out
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# Early music
thumb\|upright=1.2\|Renaissance-era lute and viol, depicted in a detail from a painting by Francesco Francia `{{History of Western art music}}`{=mediawiki} **Early music** generally comprises Medieval music (500--1400) and Renaissance music (1400--1600), but can also include Baroque music (1600--1750) or Ancient music (before 500 AD). Originating in Europe, early music is a broad musical era for the beginning of Western classical music.
## Terminology
Interpretations of historical scope of \"early music\" vary. The original Academy of Ancient Music formed in 1726 defined \"Ancient\" music as works written by composers who lived before the end of the 16th century. Johannes Brahms and his contemporaries would have understood Early music to range from the High Renaissance and Baroque, while some scholars consider that Early music should include the music of ancient Greece or Rome before 500 AD (a period that is generally covered by the term Ancient music). Music critic Michael Kennedy excludes Baroque, defining Early music as \"musical compositions from \[the\] earliest times up to and including music of \[the\] Renaissance period\".
Musicologist Thomas Forrest Kelly considers that the essence of Early music is the revival of \"forgotten\" musical repertoire and that the term is intertwined with the rediscovery of old performance practice. According to the UK\'s National Centre for Early Music, the term \"early music\" refers to both a repertory (European music written between 1250 and 1750 embracing Medieval, Renaissance and the Baroque) -- and a historically informed approach to the performance of that music.
Today, the understanding of \"Early music\" has come to include \"any music for which a historically appropriate style of performance must be reconstructed on the basis of surviving scores, treatises, instruments and other contemporary evidence.\"
## Revival
*Main article: Early music revival*
In the later 20th century there was a resurgence of interest in the performance of music from the Medieval and Renaissance eras, and a number of instrumental consorts and choral ensembles specialising in Early music repertoire were formed. Groups such as the Tallis Scholars, the Early Music Consort and the Taverner Consort and Players have been influential in bringing Early music to modern audiences through performances and popular recordings.
## Performance practice {#performance_practice}
The revival of interest in Early music has given rise to a scholarly approach to the performance of music. Through academic musicological research of music treatises, urtext editions of musical scores and other historical evidence, performers attempt to be faithful to the performance style of the musical era in which a work was originally conceived. Additionally, there has been a rise in the use of original or reproduction period instruments as part of the performance of Early music, such as the revival of the harpsichord, lute, or viol.
The practice of \"historically informed performance\" is nevertheless dependent on stylistic inference. Renaissance notation is not as prescriptive as modern scoring, and there is much that was left to the performer\'s interpretation. Margaret Bent says: \"Renaissance notation is under-prescriptive by our standards; when translated into modern form it acquires a prescriptive weight that overspecifies and distorts its original openness. Accidentals ... may or may not have been notated, but what modern notation requires would then have been perfectly apparent without notation to a singer versed in counterpoint\"
| 536 |
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| 0 |
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# Elfenland
***Elfenland*** is a German-style board game designed by Alan R. Moon and published by Amigo Spiele in German and Rio Grande Games in English in 1998. *Elfenland* won the Spiel des Jahres award in 1998.
## Background
The game was originally based on his earlier game *Elfenroads* (published by White Wind), but since *Elfenroads* took about four hours for a game, the play was simplified to reduce the time closer to an hour, making it appeal more as a family game.
## Gameplay
The game is played by 2--6 players, with 4--5 making for the best game. Each player tries to reach as many cities as possible and then return to his \"home city.\" Home cities are drawn at the beginning of the game from a pack of city cards and they remain hidden throughout the game. The game is thus reminiscent of the traveling salesman problem.
Players move using transportation cards. Elves can travel on a wide variety of vehicles including troll wagons, elf cycles, rafts, giant pigs, unicorns, dragons and magic clouds. Different types of transportation will travel better over different terrain, and some methods of transport cannot cross certain terrains at all. There is only one problem: you cannot travel over a route (except water) unless there is a tile on that road, and only the type of transport shown on the tile can be used to move along that road. Before anyone can move, tiles are drawn and laid out across the board. This part is the one that calls for the most strategy, as players try to line up their tiles to set up a nice route for themselves and a difficult one for their opponents at the same time.
As well as normal tiles, each player receives one trouble tile for use during the game. These hinder other players by forcing them to use an extra transportation card at that point. Also, any player can simply use any three cards to pass over any route that has a tile already there, allowing the type of transport shown on the tile to be ignored.
The game has subtle strategies to make others navigate through the cities. When a player puts a transportation type you don\'t want in your path then you have to find a way around it. All of the aspects of the game make for a very exciting race to visit the most cities while never quite being sure who is winning until the last round.
## Expansion
There was an expansion for *Elfenland* published, called *Elfengold*. Note that this is different from the original *Elfengold* published by White Wind.
## Reception
Bernhard Fischer from *Spieltest* praised the game\'s mechanisms, and accessibility, but was mixed on the luck elements. It also won the 1998 Spiel des Jahres award, and placed third place in the 1998 Deutscher Spiele Preis award
| 478 |
Elfenland
| 0 |
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# Empirical formula
In chemistry, the **empirical formula** of a chemical compound is the simplest whole number ratio of atoms present in a compound. A simple example of this concept is that the empirical formula of sulfur monoxide, or SO, is simply SO, as is the empirical formula of disulfur dioxide, S~2~O~2~. Thus, sulfur monoxide and disulfur dioxide, both compounds of sulfur and oxygen, have the same empirical formula. However, their molecular formulas, which express the number of atoms in each molecule of a chemical compound, are not the same.
An empirical formula makes no mention of the arrangement or number of atoms. It is standard for many ionic compounds, like calcium chloride (CaCl~2~), and for macromolecules, such as silicon dioxide (SiO~2~).
The molecular formula, on the other hand, shows the number of each type of atom in a molecule. The structural formula shows the arrangement of the molecule. It is also possible for different types of compounds to have equal empirical formulas.
In the early days of chemistry, information regarding the composition of compounds came from elemental analysis, which gives information about the relative amounts of elements present in a compound, which can be written as percentages or mole ratios. However, chemists were not able to determine the exact amounts of these elements and were only able to know their ratios, hence the name \"empirical formula\". Since ionic compounds are extended networks of anions and cations, all formulas of ionic compounds are empirical.
## Examples
- Glucose (`{{chem2|C6H12O6}}`{=mediawiki}), ribose (`{{chem2|C5H10O5}}`{=mediawiki}), acetic acid (`{{chem2|C2H4O2}}`{=mediawiki}), and formaldehyde (`{{chem2|CH2O}}`{=mediawiki}) all have different molecular formulas but the same empirical formula: `{{chem2|CH2O}}`{=mediawiki}. This is the actual molecular formula for formaldehyde, but acetic acid has double the number of atoms, ribose has five times the number of atoms, and glucose has six times the number of atoms.
| 302 |
Empirical formula
| 0 |
10,065 |
# Empirical formula
## Calculation example {#calculation_example}
A chemical analysis of a sample of methyl acetate provides the following elemental data: 48.64% carbon (C), 8.16% hydrogen (H), and 43.20% oxygen (O). For the purposes of determining empirical formulas, it\'s assumed that we have 100 grams of the compound. If this is the case, the percentages will be equal to the mass of each element in grams.
: Step 1: Change each percentage to an expression of the mass of each element in grams. That is, 48.64% C becomes 48.64 g C, 8.16% H becomes 8.16 g H, and 43.20% O becomes 43.20 g O.
```{=html}
<!-- -->
```
: Step 2: Convert the amount of each element in grams to its amount in moles
: $\left(\frac{48.64 \mbox{ g C}}{1}\right)\left(\frac{1 \mbox{ mol }}{12.01 \mbox{ g C}}\right) = 4.049\ \text{mol}$
: $\left(\frac{8.16 \mbox{ g H}}{1}\right)\left(\frac{1 \mbox{ mol }}{1.007 \mbox{ g H}}\right) = 8.095\ \text{mol}$
: $\left(\frac{43.20 \mbox{ g O}}{1}\right)\left(\frac{1 \mbox{ mol }}{16.00 \mbox{ g O}}\right) = 2.7\ \text{mol}$
```{=html}
<!-- -->
```
: Step 3: Divide each of the resulting values by the smallest of these values (2.7)
: $\frac{4.049 \mbox{ mol }}{2.7 \mbox{ mol }} = 1.5$
: $\frac{8.095 \mbox{ mol }}{2.7 \mbox{ mol }} = 3$
: $\frac{2.7 \mbox{ mol }}{2.7 \mbox{ mol }} = 1$
```{=html}
<!-- -->
```
: Step 4: If necessary, multiply these numbers by integers in order to get whole numbers; if an operation is done to one of the numbers, it must be done to all of them.
: $1.5 \times 2 = 3$
: $3 \times 2 = 6$
: $1 \times 2 = 2$
Thus, the empirical formula of methyl acetate is `{{Format molecular formula|C3H6O2}}`{=mediawiki}. This formula also happens to be methyl acetate\'s molecular formula
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# Epitaph
}} `{{Use dmy dates|date=March 2023}}`{=mediawiki} `{{Globalize|article|Western culture|date=March 2019}}`{=mediawiki}
An **epitaph** (`{{etymology|grc|''{{wikt-lang|grc|ἐπιτάφιος}}'' (epitáphios)|a funeral oration}}`{=mediawiki}; `{{etymology||''{{wikt-lang|grc|ἐπι-}}'' (epi-)|at, over||''{{wikt-lang|grc|τάφος}}'' (táphos)|tomb}}`{=mediawiki}) is a short text honoring a deceased person. Strictly speaking, it refers to text that is inscribed on a tombstone or plaque, but it may also be used in a figurative sense. Some epitaphs are specified by the person themselves before their death, while others are chosen by those responsible for the burial. An epitaph may be written in prose or in poem verse.
Most epitaphs are brief records of the family, and perhaps the career, of the deceased, often with a common expression of love or respect---for example, \"beloved father of \...\"---but others are more ambitious. From the Renaissance to the 19th century in Western culture, epitaphs for notable people became increasingly lengthy and pompous descriptions of their family origins, career, virtues and immediate family, often in Latin. Notably, the Laudatio Turiae, the longest known Ancient Roman epitaph, exceeds almost all of these at 180 lines; it celebrates the virtues of an honored wife (sometimes identified, but not generally accepted, as the Wife of consul Quintus Lucretius Vespillo).
Some are quotes from holy texts, or aphorisms. One approach of many epitaphs is to \"speak\" to the reader and warn them about their own mortality. A wry trick of others is to request the reader to get off their resting place, inasmuch as the reader would have to be standing on the ground above the coffin to read the inscription. Some record achievements (e.g., past politicians note the years of their terms of office). Nearly all (excepting those where this is impossible by definition, such as the Tomb of the Unknown Soldier) note name, year or date of birth, and date of death. Many list family members and the relationship of the deceased to them (for example, \"Father / Mother / Son / Daughter of\").
## Linguistic distinctions {#linguistic_distinctions}
In English, and in accordance with the word\'s etymology, the word \"epitaph\" refers to a *textual* commemoration of a person, which may or may not be inscribed on a monument. In many European languages, however, the meaning of the word (or its close equivalent) has broadened to mean the monument itself, specifically a mural monument or plaque erected in a church, often close to, but not directly over, a person\'s place of burial. Examples include German *Epitaph*; Dutch *epitaaf*; Hungarian *epitáfium*; Polish *epitafium*; Danish *epitafium*; Swedish *epitafium*; and Estonian *epitaaf*.
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# Epitaph
## History
The history of epitaphs extends as far back as the ancient Egyptians and have differed in delivery. The ancient Greeks utilised emotive expression, written in elegiac verse, later in prose. Ancient Romans\' use of epitaphs was more blunt and uniform, typically detailing facts of the deceased -- as did the earliest epitaphs in English churches. \"May the earth lie light upon thee\" was a common inscription for them. Due to the influence of Roman occupiers, the dominant language of epitaphs was Latin, evidenced by the oldest existing epitaphs in Britain. French and English came into fashion around the 13th and 14th centuries, respectively.
By the 16th century, epitaphs had become more literary in nature and those written in verse were involved in trade. In America and Britain, comedic epitaphs are common in the form of acrostics, palindromes, riddles, and puns on names and professions -- Robert Burns, the most prolific pre-Romantic epitaphist, wrote 35 pieces, them being largely satirical. The rate of literary epitaphs has been historically overshadowed by \"popular sepulchral inscriptions which are produced in countless numbers at all time\"; \"strictly literary\" epitaphs were most present during the start of the Romantic period.
The Lake Poets have been credited with providing success to epitaph-writing adjacent to that of poetry significance -- Robert Southey, in focusing simultaneously upon transience and eternity, contributed substantially. General interest for epitaphs was waning at the cusp of the 19th century, in contrast to a considerable burgeoning intellectual interest. Critical essays had been published before on the matter, possibly contributing towards its flourishing in the latter half of the 18th century. Epitaphs never became a major poetic form and, according to Romantic scholar Ernest Bernhardt-Kabisch, they had \"virtually disappeared\" by 1810. \"The art of the epitaph was largely lost in the 20th century\", wrote the *Encyclopedia Britannica*.
### Format
Sarcophagi and coffins were the choice of ancient Egyptians for epitaphs; brasses was the prominent format for a significant period of time. Epitaphs upon stone monuments became a common feature by the Elizabethan era.
## In England {#in_england}
### Medieval era {#medieval_era}
Stock phrases or standard elements present in epitaphs on mediaeval church monuments and ledger stones in England include:
- *Hic jacet..* (here lies\...)
- *\... cuius animae propitietur deus amen* (generally abbreviated to *cuius aie ppitiet ds ame* with tildes indicating the omitted letters) (\"whose soul may God look upon with favour Amen\")
- *Memoriae sacrum \...* / *MS* (\"Sacred to the memory (of) \...\")
### Modern era {#modern_era}
- *Requiescat in pace* / *RIP* (\"may he rest in peace\")
## Notable examples {#notable_examples}
### Poets, playwrights and other writers {#poets_playwrights_and_other_writers}
### Statesmen
### Mathematicians
### Soldiers
### Entertainers
### Activists
### Other
## Monuments with epitaphs {#monuments_with_epitaphs}
<File:Selena> Quintanilla-Perez\'s grave.jpg\|Grave of Selena at Seaside Memorial Park in Corpus Christi, Texas citing Isaiah 25:8 writings Image:Grave of W. B. Yeats; Drumecliff, Co Sligo.jpg\|Grave of W. B. Yeats, Drumecliff, Co. Sligo <File:Grabplatte> Johann Wauer Hochkirch.jpg\|Lengthy epitaph for Johann Wauer (d. 1728), a German pastor, concluding with a short Biblical quotation <File:Mel> Blanc 4-15-05.JPG\|The epitaph on voice actor Mel Blanc\'s tombstone Heather O\'Rourke crypt 2.jpg\|Inscription at Heather O\'Rourke\'s crypt <File:Sahabi> tomb.jpg\|Ezzatollah Sahabi, Glory of Iran and his patriotic daughter Haleh <File:Garner> headstone with eitaph, Houghton, Cambridgeshire.jpg\|A folksy epitaph to an English village blacksmith in Houghton, Cambridgeshire <File:Spike> Milligan\'s gravestone.jpg\|Gravestone of comedian, writer and actor Spike Milligan, including his epitaph
## In music {#in_music}
In a more figurative sense, the term may be used for music composed in memory of the deceased. Igor Stravinsky composed in 1958 *Epitaphium* for flute, clarinet and harp. In 1967 Krzysztof Meyer called his Symphony No. 2 for choir and orchestra *Epitaphium Stanisław Wiechowicz in memoriam*. Jeffrey Lewis composed *Epitaphium -- Children of the Sun* for narrator, chamber choir, piano, flute, clarinet and percussion. In 1969, King Crimson released the song Epitaph, giving a reference to epitaphs within the song. Bronius Kutavičius composed in 1998 *Epitaphium temporum pereunti*. Valentin Silvestrov composed in 1999 *Epitaph L.B.* (Епітафія Л.Б.) for viola (or cello) and piano. In 2007 Graham Waterhouse composed *Epitaphium* for string trio as a tribute to the memory of his father William Waterhouse. The South African poet Gert Vlok Nel wrote an (originally) untitled song, which appeared on his first music album \"Beaufort-Wes se Beautiful Woorde\" as \"Epitaph\", because his producer Eckard Potgieter told him that the song sounded like an epitaph. David Bowie\'s final album, *Blackstar*, released in 2016, is generally seen as his musical epitaph, with singles \"Blackstar\" and \"Lazarus\" often singled out
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# European Convention on Nationality
The **European Convention on Nationality** (E.T.S. No. 166) was signed in Strasbourg on 6 November 1997. It is a comprehensive convention of the Council of Europe dealing with the law of nationality. The convention is open for signature by the member States of the Council of Europe and the non-member States which have participated in its elaboration and for accession by other non-member States. The Convention came into force on 1 March 2000 after ratification by 3 countries. `{{As of|2021}}`{=mediawiki}, the convention has been signed by 29 countries and ratified by 21 of those countries.
## Provisions
Article 4(d) provides that neither marriage nor dissolution of marriage shall automatically affect the nationality of either spouse, nor shall a change of nationality by one spouse during marriage automatically affect the nationality of their spouse. Common practice among states at the beginning of the 20th century was that a woman was to have the nationality of her husband; i.e., upon marrying a foreigner the wife would automatically acquire the nationality of her husband, and lose her previous nationality. Even after the nationality of a married woman was no longer dependent on the nationality of her husband, legal provisions were still retained which automatically naturalised married women, and sometimes married men as well. This led to a number of problems, such as loss of the spouses\' original nationality, the spouse losing the right to consular assistance (since consular assistance cannot be provided to nationals under the jurisdiction of a foreign state of which they are also nationals), and becoming subject to military service obligations. Article 4d addresses this situation.
Article 5 provides that no discrimination shall exist in a state\'s internal nationality law on the grounds of \"sex, religion, race, colour or national or ethnic origin\". It also provides that a state shall not discriminate amongst its nationals on the basis of whether they hold their nationality by birth or acquired it subsequently.
Article 6 relates to the acquisition of nationality. It provides for nationality to be acquired at birth by descent from either parent to those born within the territory of the state. (States may exclude partially or fully children born abroad). It also provides for nationality by virtue of birth in the territory of state; however, states may limit this to only children who would be otherwise stateless. It requires the possibility of naturalisation, and provides that the period of residence required for eligibility cannot be more than ten years lawful and habitual residence. It also requires to \"facilitate\" the acquisition of nationality by certain persons, including spouses of nationals, children of its nationals born abroad, children one of whose parents has acquired the nationality, children adopted by a national, persons lawfully and habitually resident for a period before the age of eighteen, and stateless persons and refugees lawfully and habitually resident on its territory.
Article 7 regulates the involuntary loss of nationality. It provides that states may deprive their nationals of their nationality in only the cases of voluntary acquisition of another nationality, fraud or failure to provide relevant information when acquiring nationality, voluntary military service in a foreign military force, or adoption as a child by foreign nationals. It also provides for the possibility of loss of nationality for nationals habitually residing abroad. Finally, it provides loss of nationality for \"conduct seriously prejudicial to the vital interests of the State Party\".
Article 8 provides nationals with the right to renounce their nationality, providing they do not thereby become stateless. States may however restrict this right with respect to nationals residing abroad
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# European Currency Unit
The **European Currency Unit** (*Unité de compte européenne*, *Unidad Monetaria Europea*, *Europäische Währungseinheit*`{{Hsp}}`{=mediawiki}; ⟨**`{{char|₠}}`{=mediawiki}**⟩, **ECU**, or **XEU**) was a unit of account used by the European Economic Community and composed of a basket of member country currencies. The ECU came in to operation on 13 March 1979 and was assigned the ISO 4217 code. The ECU replaced the European Unit of Account (EUA) at parity in 1979, and it was later replaced by the euro (EUR) at parity on 1 January 1999.
As a unit of account, the ECU was not a circulating currency and did not replace or override the value of the currency of EEC member countries. However, it was used to price some international financial transactions and capital transfers.
## Exchange rate {#exchange_rate}
Using a mechanism known as the \"snake in the tunnel\", the European Exchange Rate Mechanism was an attempt to minimize fluctuations between member state currencies---initially by managing the variance of each against its respective ECU reference rate---with the aim to achieve fixed ratios over time, and so enable the European Single Currency (which became known as the euro) to replace national currencies.
## Hard ECU proposal {#hard_ecu_proposal}
In 1990 the British Chancellor of the Exchequer John Major proposed the creation of a \'hard\' ECU, which different national currencies could compete against and, if the ECU was successful, could lead to a single currency. The move was seen by France and Germany as a wrecking tactic, especially when the increasingly Eurosceptic Thatcher announced her outright opposition to the European Economic and Monetary Union (EMU), and the idea was abandoned.
## Euro replaces the ECU {#euro_replaces_the_ecu}
On 1 January 1999, the euro (with the code EUR and symbol ⟨€⟩) replaced the ECU at par (one-to-one). Unlike the ECU, the euro is a real currency, although not all member states participate (for details on euro membership see Eurozone). Two of the countries in the ECU basket of currencies, the UK and Denmark, did not join the eurozone, and a third, Greece, joined late. On the other hand, Finland and Austria joined the eurozone from the beginning, even though their currencies were not part of the ECU basket, since they had joined the EU in 1995, two years after the ECU composition was \"frozen\".
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# European Currency Unit
## Euro replaces the ECU {#euro_replaces_the_ecu}
### Legal implications {#legal_implications}
Due to the ECU being used in some international financial transactions, there was a concern that foreign courts might not recognize the euro as the legal successor to the ECU. This was unlikely to be a problem, since it is a generally accepted principle of private international law that states determine their currencies, and that therefore states would accept the European Union legislation to that effect. However, for abundant caution, several foreign jurisdictions adopted legislation to ensure a smooth transition. Of particular importance, the U.S. states of Illinois and New York adopted legislation to ensure a large proportion of international financial contracts recognized the euro as the successor of the ECU.
## Symbol and name {#symbol_and_name}
The ECU\'s symbol, **₠**, consists of an interlaced *C* and *E*`{{Hsp}}`{=mediawiki}---the initials of \"European Community\" in many languages of Europe. However, the symbol was not widely adopted. Few computer systems utilized by financial institutions and governments could render it, and commercial payment systems were obliged to use the ISO code, XEU, as with other currencies without widely recognised currency symbols. The Unicode designation for the ECU symbol (`{{Unichar|20A0|EURO-CURRENCY SIGN}}`{=mediawiki}) was not implemented on many personal computer operating systems until the release of Unicode v2.1 in May 1998, which also introduced the euro sign (`{{Unichar|20AC|EURO SIGN}}`{=mediawiki}). Microsoft did include the ECU symbol in many of its European versions of Windows beginning in the early 1990s; however, accessing it required the use of an Alt code, and not all typefaces provided a glyph. By 2009, Microsoft referred to the ECU symbol as \"historical\". Support among other operating systems, including Macintosh operating systems, was inconsistent.
Although the acronym for ECU is formed from the English name of the unit, the écu was a family of gold coins minted during the reign of Louis IX of France. The name of the ECU\'s successor, the euro, was chosen because the name did not favor any single language, nation, or historical period.
## Currency basket {#currency_basket}
Period No. of national currency units (weight, i.e. % contribution to total value)
------------ -----------------------------------------------------------------------------
1979--1984 BEF
3.80 (9.64%)
1984--1989 BEF
3.85 (8.57%)
1989--1998 BEF
3.301 (8.183%)
1999 EUR
1
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# Eastern Caribbean dollar
The **Eastern Caribbean dollar** (symbol: **EC\$**; code: **XCD**) is the currency of all seven full members and one associate member of the Organisation of Eastern Caribbean States (OECS). The successor to the British West Indies dollar, it has existed since 1965, and it is normally abbreviated with the dollar sign *\$* or, alternatively, *EC\$* to distinguish it from other dollar-denominated currencies. The EC\$ is subdivided into 100 cents. It has been pegged to the United States dollar since 7 July 1976, at the exchange rate of `{{US$|1}}`{=mediawiki} = `{{currency|2|code=XCD}}`{=mediawiki}.70.
## Circulation
Six of the states using the EC\$ are independent states: Antigua and Barbuda, Dominica, Grenada, Saint Kitts and Nevis, Saint Lucia, and Saint Vincent and the Grenadines. The other two, Anguilla and Montserrat, are British Overseas Territories. These states are all members of the Eastern Caribbean Currency Union.
Other associate members of the OECS do not use the Eastern Caribbean dollar as their official currency: the British Virgin Islands, Guadeloupe and Martinique. The British Virgin Islands were always problematic for currency purposes due to their proximity to the Danish West Indies, which became the United States Virgin Islands in 1917. Officially, the British Virgin Islands used to use sterling, but in practice the situation was more complicated and involved the circulation of French francs and U.S. dollars. In 1951, the British Virgin Islands adopted the British West Indies dollar which at that time operated in conjunction with the sterling coinage, and in 1959 they changed over officially to the U.S. dollar.
Guadeloupe and Martinique, as part of France, use the euro as its currency.
British Guiana and Barbados had previously been members of the Eastern Caribbean Currency Union but withdrew in 1966 and 1972, respectively. Trinidad and Tobago had been a member of the earlier British West Indies currency union, but withdrew in 1964.
The combined population of the EC\$ area is about 613,000 (2014 census and estimates), which is comparable to Montenegro or the American capital city of Washington, D.C. The combined GDP is 5.46 billion US dollars, which is comparable to Bermuda.
The late Queen Elizabeth II appears on the banknotes and also on the obverse of the coins. She was the head of state of all the states and territories using the EC\$, except for Dominica (which was granted independence from the United Kingdom as a Republic). Dominica is nevertheless a member of the Commonwealth of Nations which now recognizes King Charles III as Head of the Commonwealth.
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# Eastern Caribbean dollar
## History
Queen Anne\'s proclamation of 1704 was the first attempt to introduce sterling currency to the British West Indies, however it failed to displace the existing Spanish dollar currency system right up until the late 1870s. In 1822, the British government coined `{{1/4}}`{=mediawiki}, `{{frac|1|8}}`{=mediawiki}, and `{{frac|1|16}}`{=mediawiki} fractional \'Anchor dollars\' for use in Mauritius and the British West Indies (but not Jamaica). A few years later copper fractional dollars were coined for Mauritius, Sierra Leone, and the British West Indies.
The next attempts to introduce British sterling silver coinage to the colonies came with an imperial order-in-council dated 1825. This move was inspired by a number of factors. The United Kingdom was now operating a very successful gold standard in relation to the gold sovereign that was introduced in 1816, and there was a desire to extend this system to the colonies. In addition to this, there was that the supply of Spanish dollars (pieces of eight) had been cut off as a result of the revolutions in Latin America where most of the Spanish dollars were minted. The last Spanish Dollar was in fact minted at Potosi in 1825. There was now a growing desire to have a stable and steady supply of British shillings everywhere the British drum was beating. The 1825 order-in-council was largely a failure because it made sterling silver coinage legal tender at the unrealistic rating in relation to the Spanish dollar of `{{val|p=$|1}}`{=mediawiki} = 4 shillings 4 pence. It succeeded in Jamaica, Bermuda, and British Honduras because the authorities in those territories set aside the official ratings and used the more realistic rating of `{{val|p=$|1}}`{=mediawiki} = 4 shillings. The reality of the rating between the dollar and the pound was based on the silver content of the Spanish pieces of eight as compared to the gold content of the British gold sovereign.
A second imperial order-in-council was passed in 1838 with the correct rating of `{{val|p=$|1}}`{=mediawiki} = 4 shillings 2 pence. In the years following the 1838 order-in-council, the British West Indies territories began to enact local legislation for the purposes of assimilating their monies of account with the British pound sterling. Gold discoveries in Australia in 1851 drove the silver dollar out of the West Indies, but it returned again with the great depreciation in the value of silver that followed with Germany\'s transition to the gold standard between 1871 and 1873. In the years immediately following 1873, there was a fear that the British West Indies might return to a silver standard. As such, legislation was passed in the individual territories to demonetize the silver dollars. Even though the British coinage was also silver, it represented fractions of the gold sovereign and so its value was based on a gold standard.
During this period, and into the nineteenth century, accounts could be kept in either dollars or sterling. Jamaica, Bermuda, and the Bahamas preferred to use sterling accounts whereas British Guiana used dollar accounts. British Guiana used dollar accounts for the purpose of assisting in the transition from the Dutch guilder system of currency to the British pound sterling system. In the Eastern Caribbean territories the private sector preferred to use dollar accounts whereas the government preferred to use sterling accounts. In some of the Eastern Caribbean territories, notes were issued by various private banks, denominated in dollars equivalent to 4 shillings 2 pence. See Antigua dollar, Barbadian dollar, Dominican dollar, Grenadian dollar, Guyanese dollar, Saint Kitts dollar, Saint Lucia dollar, Saint Vincent dollar and Trinidad and Tobago dollar.
In 1946, a West Indian Currency Conference saw Barbados, British Guiana, the Leeward Islands, Trinidad and Tobago and the Windward Islands agree to establish a unified decimal currency system based on a West Indian dollar to replace the current arrangement of having three different Boards of Commissioners of Currency (for Barbados (which also served the Leeward and Windward Islands), British Guiana and Trinidad & Tobago).
In 1949, the British government formalized the dollar system of accounts in British Guiana and the Eastern Caribbean territories by introducing the British West Indies dollar (BWI\$) at the already existing conversion rate of `{{val|p=$|4.80}}`{=mediawiki} per pound sterling (or `{{val|p=$|1}}`{=mediawiki} = 4 shillings 2 pence). It was one of the many experimental political and economic ventures tested by the British government to form a uniform system within the British West Indies territories. The symbol \"BWI\$\" was frequently used and the currency was known verbally as the \"Beewee\" (slang for British West Indies) dollar. Shortly thereafter in 1950, the British Caribbean Currency Board (BCCB) was set up in Trinidad with the sole right to issue notes and coins of the new unified currency and given the mandate of keeping full foreign exchange cover to ensure convertibility at `{{val|p=$|4}}`{=mediawiki}.80 per pound sterling. In 1951, the British Virgin Islands joined the arrangement, but this led to discontent because that territory was more naturally drawn to the currency of the neighbouring U.S. Virgin Islands. In 1961, the British Virgin Islands withdrew from the arrangement and adopted the U.S. dollar.
Until 1955, the BWI\$ existed only as banknotes in conjunction with sterling fractional coinage. Decimal coins replaced the sterling coins in 1955. These decimal coins were denominated in cents, with each cent worth one halfpenny in sterling.
In 1958, the West Indies Federation was established and the BWI\$ was its currency. However, although Jamaica (including the Cayman Islands and the Turks and Caicos Islands) was part of the West Indies Federation, it retained the Jamaican pound, despite adopting the BWI\$ as legal tender from 1954. Jamaica, the Cayman Islands, and the Turks and Caicos Islands were already long established users of the sterling accounts system of pounds, shillings, and pence.
In 1964 Jamaica ended the legal tender status of the BWI\$ and Trinidad and Tobago withdrew from the currency union (adopting the Trinidad and Tobago dollar) forcing the movement of the headquarters of the BCCB to Barbados and soon the \"BWI\$\" dollar lost its regional support.
In 1965, the British West Indies dollar of the now defunct West Indies Federation was replaced at par by the Eastern Caribbean dollar and the BCCB was replaced by the Eastern Caribbean Currency Authority or ECCA (established by the Eastern Caribbean Currency Agreement 1965). British Guiana withdrew from the currency union the following year. Grenada, which had used the Trinidad and Tobago dollar from 1964, rejoined the common currency arrangement in 1968. Barbados withdrew from the currency union in 1972, following which the ECCA headquarters were moved to St. Kitts.
Between 1965 and 1983, the Eastern Caribbean Currency Authority issued the EC\$, with banknotes from 1965 and coins from 1981. The EC\$ is now issued by the Eastern Caribbean Central Bank, based in the city of Basseterre, in Saint Kitts and Nevis. The bank was established by an agreement (the Eastern Caribbean Central Bank Agreement) signed at Port of Spain on 5 July 1983.
The exchange rate of `{{val|p=$|4.80}}`{=mediawiki} = £1 sterling (equivalent to the old `{{val|p=$|1}}`{=mediawiki} = 4s 2d) continued until 1976 for the new Eastern Caribbean dollar.
For a wider outline of the history of currency in the region see Currencies of the British West Indies.
## Coins
Until 1981, the coins of the BWI\$ circulated. In 1982, a new series of coins was introduced in denominations of 1, 2, 5, 10 and 25 cents and 1 dollar. The 1 and 5 cent coins were scalloped in shape while the 2 cent coin was square. These three were struck in aluminum. The 10 and 25 cent coins were round and cupro-nickel. The dollar was aluminum bronze and also round. The round, aluminum bronze dollar coin was replaced in 1989 with a decagonal, cupro-nickel type. In 2002 new and larger round-shaped 1, 2, and 5 cent pieces were introduced, along with a new 1 dollar coin which was also round. The effigy of Queen Elizabeth II was also changed that same year on all coin denominations to the Ian Rank-Broadley design, making it the last commonwealth currency up to that date to discontinue the Arnold Machin portrait. Their compositions remained aluminum and cupro-nickel, respectively. Higher denominations exist, but these were issued only as medal-coins. 1 and 2 cent coins were withdrawn from circulation in July 2015, and remained legal tender until 30 June 2020.
Value Technical parameters
---------- ---------------------- ------------- ------
Diameter Mass Composition Edge
: 2002 Series [1](http://www.eccb-centralbank.org/Currency/cur_newcoins.asp) `{{Webarchive|url=https://web.archive.org/web/20110927065122/http://www.eccb-centralbank.org/Currency/cur_newcoins
| 1,398 |
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# Electroweak interaction
In particle physics, the **electroweak interaction** or **electroweak force** is the unified description of two of the fundamental interactions of nature: electromagnetism (electromagnetic interaction) and the weak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 246 GeV, they would merge into a single force. Thus, if the temperature is high enough -- approximately 10^15^ K -- then the electromagnetic force and weak force merge into a combined electroweak force.
During the quark epoch (shortly after the Big Bang), the electroweak force split into the electromagnetic and weak force. It is thought that the required temperature of 10^15^ K has not been seen widely throughout the universe since before the quark epoch, and currently the highest human-made temperature in thermal equilibrium is around `{{val|5.5|e=12|u=K}}`{=mediawiki} (from the Large Hadron Collider).
Sheldon Glashow, Abdus Salam, and Steven Weinberg were awarded the 1979 Nobel Prize in Physics for their contributions to the unification of the weak and electromagnetic interaction between elementary particles, known as the **Weinberg--Salam theory**. The existence of the electroweak interactions was experimentally established in two stages, the first being the discovery of neutral currents in neutrino scattering by the Gargamelle collaboration in 1973, and the second in 1983 by the UA1 and the UA2 collaborations that involved the discovery of the W and Z gauge bosons in proton--antiproton collisions at the converted Super Proton Synchrotron. In 1999, Gerardus \'t Hooft and Martinus Veltman were awarded the Nobel prize for showing that the electroweak theory is renormalizable.
## History
After the Wu experiment in 1956 discovered parity violation in the weak interaction, a search began for a way to relate the weak and electromagnetic interactions. Extending his doctoral advisor Julian Schwinger\'s work, Sheldon Glashow first experimented with introducing two different symmetries, one chiral and one achiral, and combined them such that their overall symmetry was unbroken. This did not yield a renormalizable theory, and its gauge symmetry had to be broken by hand as no spontaneous mechanism was known, but it predicted a new particle, the Z boson. This received little notice, as it matched no experimental finding.
In 1964, Salam and John Clive Ward had the same idea, but predicted a massless photon and three massive gauge bosons with a manually broken symmetry. Later around 1967, while investigating spontaneous symmetry breaking, Weinberg found a set of symmetries predicting a massless, neutral gauge boson. Initially rejecting such a particle as useless, he later realized his symmetries produced the electroweak force, and he proceeded to predict rough masses for the W and Z bosons. Significantly, he suggested this new theory was renormalizable. In 1971, Gerard \'t Hooft proved that spontaneously broken gauge symmetries are renormalizable even with massive gauge bosons.
| 474 |
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# Electroweak interaction
## Formulation
upright=1.25\|thumb\|Weinberg\'s weak mixing angle `{{mvar|θ}}`{=mediawiki}`{{sub|W}}`{=mediawiki}, and relation between coupling constants `{{mvar|g, g′}}`{=mediawiki}, and `{{mvar|e}}`{=mediawiki}. Adapted from Lee (1981). upright=1.25\|thumb\|The pattern of weak isospin, `{{mvar|T}}`{=mediawiki}`{{sub|3}}`{=mediawiki}, and weak hypercharge, `{{mvar|Y}}`{=mediawiki}`{{sub|{{sc|w}}}}`{=mediawiki}, of the known elementary particles, showing the electric charge, `{{mvar|Q}}`{=mediawiki}, along the weak mixing angle. The neutral Higgs field (circled) breaks the electroweak symmetry and interacts with other particles to give them mass. Three components of the Higgs field become part of the massive `{{SubatomicParticle|W boson}}`{=mediawiki} and `{{SubatomicParticle|Z boson}}`{=mediawiki} bosons.
Mathematically, electromagnetism is unified with the weak interactions as a Yang--Mills field with an `{{nowrap|1=[[SU(2)]] × [[Unitary group|U(1)]]}}`{=mediawiki} gauge group, which describes the formal operations that can be applied to the electroweak gauge fields without changing the dynamics of the system. These fields are the weak isospin fields `{{mvar|W}}`{=mediawiki}`{{sub|1}}`{=mediawiki}, `{{mvar|W}}`{=mediawiki}`{{sub|2}}`{=mediawiki}, and `{{mvar|W}}`{=mediawiki}`{{sub|3}}`{=mediawiki}, and the weak hypercharge field `{{mvar|B}}`{=mediawiki}. This invariance is known as **electroweak symmetry**.
The generators of SU(2) and U(1) are given the name weak isospin (labeled `{{mvar|T}}`{=mediawiki}) and weak hypercharge (labeled `{{mvar|Y}}`{=mediawiki}) respectively. These then give rise to the gauge bosons that mediate the electroweak interactions -- the three `{{math|W}}`{=mediawiki} bosons of weak isospin (`{{math|''W''}}`{=mediawiki}`{{sub|1}}`{=mediawiki}, `{{math|''W''}}`{=mediawiki}`{{sub|2}}`{=mediawiki}, and `{{math|''W''}}`{=mediawiki}`{{sub|3}}`{=mediawiki}), and the `{{math|''B''}}`{=mediawiki} boson of weak hypercharge, respectively, all of which are \"initially\" massless. These are not physical fields yet, before spontaneous symmetry breaking and the associated Higgs mechanism.
In the Standard Model, the observed physical particles, the `{{SubatomicParticle|W boson+-}}`{=mediawiki} and `{{SubatomicParticle|Z boson0}}`{=mediawiki} bosons, and the photon, are produced through the spontaneous symmetry breaking of the electroweak symmetry SU(2) × U(1)`{{sub|{{sc|y}}}}`{=mediawiki} to U(1)`{{sub|em}}`{=mediawiki}, effected by the Higgs mechanism (see also Higgs boson), an elaborate quantum-field-theoretic phenomenon that \"spontaneously\" alters the realization of the symmetry and rearranges degrees of freedom.
The electric charge arises as the particular linear combination (nontrivial) of `{{mvar|Y}}`{=mediawiki}`{{sub|{{sc|w}}}}`{=mediawiki} (weak hypercharge) and the `{{mvar|T}}`{=mediawiki}`{{sub|3}}`{=mediawiki} component of weak isospin ($Q = T_3 + \tfrac{1}{2}\,Y_\mathrm{W}$) that does *not* couple to the Higgs boson. That is to say: the Higgs and the electromagnetic field have no effect on each other, at the level of the fundamental forces (\"tree level\"), while any *other* combination of the hypercharge and the weak isospin must interact with the Higgs. This causes an apparent separation between the weak force, which interacts with the Higgs, and electromagnetism, which does not. Mathematically, the electric charge is a specific combination of the hypercharge and `{{mvar|T}}`{=mediawiki}`{{sub|3}}`{=mediawiki} outlined in the figure.
(the symmetry group of electromagnetism only) is defined to be the group generated by this special linear combination, and the symmetry described by the `{{math|U(1)}}`{=mediawiki}`{{sub|em}}`{=mediawiki} group is unbroken, since it does not *directly* interact with the Higgs.
The above spontaneous symmetry breaking makes the `{{mvar|W}}`{=mediawiki}`{{sub|3}}`{=mediawiki} and `{{mvar|B}}`{=mediawiki} bosons coalesce into two different physical bosons with different masses -- the `{{SubatomicParticle|Z boson0}}`{=mediawiki} boson, and the photon (`{{math|{{SubatomicParticle|photon}}}}`{=mediawiki}),
: \\begin{pmatrix}
\\gamma \\\\ Z\^0 \\end{pmatrix} = \\begin{pmatrix} \\cos \\theta\_\\text{W} & \\sin \\theta\_\\text{W} \\\\ -\\sin \\theta\_\\text{W} & \\cos \\theta\_\\text{W} \\end{pmatrix} \\begin{pmatrix} B \\\\ W_3 \\end{pmatrix} , where `{{mvar|θ}}`{=mediawiki}`{{sub|{{sc|w}}}}`{=mediawiki} is the *weak mixing angle*. The axes representing the particles have essentially just been rotated, in the (`{{mvar|W}}`{=mediawiki}`{{sub|3}}`{=mediawiki}, `{{mvar|B}}`{=mediawiki}) plane, by the angle `{{mvar|θ}}`{=mediawiki}`{{sub|{{sc|w}}}}`{=mediawiki}. This also introduces a mismatch between the mass of the `{{SubatomicParticle|Z boson0}}`{=mediawiki} and the mass of the `{{SubatomicParticle|W boson+-}}`{=mediawiki} particles (denoted as `{{mvar|m}}`{=mediawiki}`{{sub|{{sc|z}}}}`{=mediawiki} and `{{mvar|m}}`{=mediawiki}`{{sub|{{sc|w}}}}`{=mediawiki}, respectively),
: $m_\text{Z} = \frac{m_\text{W}}{\,\cos\theta_\text{W}\,} ~.$
The `{{mvar|W}}`{=mediawiki}`{{sub|1}}`{=mediawiki} and `{{mvar|W}}`{=mediawiki}`{{sub|2}}`{=mediawiki} bosons, in turn, combine to produce the charged massive bosons `{{SubatomicParticle|W boson+-}}`{=mediawiki}:
: $W^{\pm} = \frac{1}{\sqrt{2\,}}\,\bigl(\,W_1 \mp i W_2\,\bigr) ~.$
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# Electroweak interaction
## Lagrangian
### Before electroweak symmetry breaking {#before_electroweak_symmetry_breaking}
The Lagrangian for the electroweak interactions is divided into four parts before electroweak symmetry breaking manifests,
: $\mathcal{L}_{\mathrm{EW}} = \mathcal{L}_g + \mathcal{L}_f + \mathcal{L}_h + \mathcal{L}_y~.$
The $\mathcal{L}_g$ term describes the interaction between the three `{{mvar|W}}`{=mediawiki} vector bosons and the `{{mvar|B}}`{=mediawiki} vector boson,
: $\mathcal{L}_g = -\tfrac{1}{4} W_{a}^{\mu\nu}W_{\mu\nu}^a - \tfrac{1}{4} B^{\mu\nu}B_{\mu\nu},$
where $W_{a}^{\mu\nu}$ ($a=1,2,3$) and $B^{\mu\nu}$ are the field strength tensors for the weak isospin and weak hypercharge gauge fields.
$\mathcal{L}_f$ is the kinetic term for the Standard Model fermions. The interaction of the gauge bosons and the fermions are through the gauge covariant derivative,
: $\mathcal{L}_f = \overline{Q}_j iD\!\!\!\!/\; Q_j+ \overline{u}_j iD\!\!\!\!/\; u_j+ \overline{d}_j iD\!\!\!\!/\; d_j + \overline{L}_j iD\!\!\!\!/\; L_j + \overline{e}_j iD\!\!\!\!/\; e_j,$
where the subscript `{{mvar|j}}`{=mediawiki} sums over the three generations of fermions; `{{mvar|Q}}`{=mediawiki}, `{{mvar|u}}`{=mediawiki}, and `{{mvar|d}}`{=mediawiki} are the left-handed doublet, right-handed singlet up, and right handed singlet down quark fields; and `{{mvar|L}}`{=mediawiki} and `{{mvar|e}}`{=mediawiki} are the left-handed doublet and right-handed singlet electron fields. The Feynman slash $D\!\!\!\!/$ means the contraction of the 4-gradient with the Dirac matrices, defined as
: $D\!\!\!\!/ \equiv \gamma^\mu\ D_\mu,$
and the covariant derivative (excluding the gluon gauge field for the strong interaction) is defined as
: $\ D_\mu \equiv \partial_\mu - i\ \frac{g'}{2}\ Y\ B_\mu - i\ \frac{g}{2}\ T_j\ W_\mu^j.$
Here $\ Y\$ is the weak hypercharge and the $\ T_j\$ are the components of the weak isospin.
The $\mathcal{L}_h$ term describes the Higgs field $h$ and its interactions with itself and the gauge bosons,
: $\mathcal{L}_h = |D_\mu h|^2 - \lambda \left(|h|^2 - \frac{v^2}{2}\right)^2\ ,$
where $v$ is the vacuum expectation value.
The $\ \mathcal{L}_y\$ term describes the Yukawa interaction with the fermions,
: $\mathcal{L}_y = - y_{u}^{ij}\epsilon^{ab}\ h_b^\dagger\ \overline{Q}_{ia} u_j^c - y_{d}^{ij}\ h\ \overline{Q}_i d^c_j - y_{e}^{ij}\ h\ \overline{L}_i e^c_j + \mathrm{h.c.} ~,$
and generates their masses, manifest when the Higgs field acquires a nonzero vacuum expectation value, discussed next. The $\ y_k^{ij}\ ,$ for $\ k \in \{ \mathrm{u, d, e} \}\ ,$ are matrices of Yukawa couplings.
### After electroweak symmetry breaking {#after_electroweak_symmetry_breaking}
The Lagrangian reorganizes itself as the Higgs field acquires a non-vanishing vacuum expectation value dictated by the potential of the previous section. As a result of this rewriting, the symmetry breaking becomes manifest. In the history of the universe, this is believed to have happened shortly after the hot big bang, when the universe was at a temperature `{{val|159.5|1.5|ul=GeV}}`{=mediawiki} (assuming the Standard Model of particle physics).
Due to its complexity, this Lagrangian is best described by breaking it up into several parts as follows.
: $\mathcal{L}_{\mathrm{EW}} = \mathcal{L}_\mathrm{K} + \mathcal{L}_\mathrm{N} + \mathcal{L}_\mathrm{C} + \mathcal{L}_\mathrm{H} + \mathcal{L}_{\mathrm{HV}} + \mathcal{L}_{\mathrm{WWV}} + \mathcal{L}_{\mathrm{WWVV}} + \mathcal{L}_\mathrm{Y} ~.$
The kinetic term $\mathcal{L}_K$ contains all the quadratic terms of the Lagrangian, which include the dynamic terms (the partial derivatives) and the mass terms (conspicuously absent from the Lagrangian before symmetry breaking)
:
\\begin{align} \\mathcal{L}\_\\mathrm{K} = \\sum_f \\overline{f}(i\\partial\\!\\!\\!/\\!\\;-m_f)\\ f - \\frac{1}{4}\\ A\_{\\mu\\nu}\\ A\^{\\mu\\nu} - \\frac{1}{2}\\ W\^+\_{\\mu\\nu}\\ W\^{-\\mu\\nu} + m_W\^2\\ W\^+\_\\mu\\ W\^{-\\mu} \\\\ \\qquad -\\frac{1}{4}\\ Z\_{\\mu\\nu}Z\^{\\mu\\nu} + \\frac{1}{2}\\ m_Z\^2\\ Z\_\\mu\\ Z\^\\mu + \\frac{1}{2}\\ (\\partial\^\\mu\\ H)(\\partial\_\\mu\\ H) - \\frac{1}{2}\\ m_H\^2\\ H\^2 \~, \\end{align} where the sum runs over all the fermions of the theory (quarks and leptons), and the fields $\ A_{\mu\nu}\ ,$ $\ Z_{\mu\nu}\ ,$ $\ W^-_{\mu\nu}\ ,$ and $\ W^+_{\mu\nu} \equiv (W^-_{\mu\nu})^\dagger\$ are given as
: $X^{a}_{\mu\nu} = \partial_\mu X^{a}_\nu - \partial_\nu X^{a}_\mu + g f^{abc}X^{b}_{\mu}X^{c}_{\nu} ~,$
with $X$ to be replaced by the relevant field ($A,$ $Z,$ $W^\pm$) and `{{mvar|f {{sup|abc}} }}`{=mediawiki} by the structure constants of the appropriate gauge group.
The neutral current $\ \mathcal{L}_\mathrm{N}\$ and charged current $\ \mathcal{L}_\mathrm{C}\$ components of the Lagrangian contain the interactions between the fermions and gauge bosons,
: $\mathcal{L}_\mathrm{N} = e\ J_\mu^\mathrm{em}\ A^\mu + \frac{g}{\ \cos\theta_W\ }\ (\ J_\mu^3 - \sin^2\theta_W\ J_\mu^\mathrm{em}\ )\ Z^\mu ~,$
where $~e = g\ \sin \theta_\mathrm{W} = g'\ \cos \theta_\mathrm{W} ~.$ The electromagnetic current $\; J_\mu^{\mathrm{em}} \;$ is
: $J_\mu^\mathrm{em} = \sum_f \ q_f\ \overline{f}\ \gamma_\mu\ f ~,$
where $\ q_f\$ is the fermions\' electric charges. The neutral weak current $\ J_\mu^3\$ is
: $J_\mu^3 = \sum_f\ T^3_f\ \overline{f}\ \gamma_\mu\ \frac{\ 1-\gamma^5\ }{2}\ f ~,$
where $T^3_f$ is the fermions\' weak isospin.
The charged current part of the Lagrangian is given by
: $\mathcal{L}_\mathrm{C} = -\frac{g}{\ \sqrt{2 \;}\ }\ \left[\ \overline{u}_i\ \gamma^\mu\ \frac{\ 1 - \gamma^5\ }{2} \; M^{\mathrm{CKM}}_{ij}\ d_j + \overline{\nu}_i\ \gamma^\mu\;\frac{\ 1-\gamma^5\ }{2} \; e_i\ \right]\ W_\mu^{+} + \mathrm{h.c.} ~,$
where $\ \nu\$ is the right-handed singlet neutrino field, and the CKM matrix $M_{ij}^\mathrm{CKM}$ determines the mixing between mass and weak eigenstates of the quarks.
$\mathcal{L}_\mathrm{H}$ contains the Higgs three-point and four-point self interaction terms,
: $\mathcal{L}_\mathrm{H} = -\frac{\ g\ m_\mathrm{H}^2\,}{\ 4\ m_\mathrm{W}\ }\;H^3 - \frac{\ g^2\ m_\mathrm{H}^2\ }{32\ m_\mathrm{W}^2}\;H^4 ~.$
$\mathcal{L}_{\mathrm{HV}}$ contains the Higgs interactions with gauge vector bosons,
: $\mathcal{L}_\mathrm{HV} =\left(\ g\ m_\mathrm{HV} + \frac{\ g^2\ }{4}\;H^2\ \right)\left(\ W^{+}_\mu\ W^{-\mu} + \frac{1}{\ 2\ \cos^2\ \theta_\mathrm{W}\ }\;Z_\mu\ Z^\mu\ \right) ~.$
$\mathcal{L}_{\mathrm{WWV}}$ contains the gauge three-point self interactions,
: $\mathcal{L}_{\mathrm{WWV}} = -i\ g\ \left[\; \left(\ W_{\mu\nu}^{+}\ W^{-\mu} - W^{+\mu}\ W^{-}_{\mu\nu}\ \right)\left(\ A^\nu\ \sin \theta_\mathrm{W} - Z^\nu\ \cos\theta_\mathrm{W}\ \right) + W^{-}_\nu\ W^{+}_\mu\ \left(\ A^{\mu\nu}\ \sin \theta_\mathrm{W} - Z^{\mu\nu}\ \cos \theta_\mathrm{W}\ \right) \;\right] ~.$
$\mathcal{L}_{\mathrm{WWVV}}$ contains the gauge four-point self interactions,
:
\\begin{align} \\mathcal{L}\_{\\mathrm{WWVV}} = -\\frac{\\ g\^2\\ }{4}\\ \\Biggl\\{\\ &\\Bigl\[\\ 2\\ W\^{+}\_\\mu\\ W\^{-\\mu} + (\\ A\_\\mu\\ \\sin \\theta\_\\mathrm{W} - Z\_\\mu\\ \\cos \\theta\_\\mathrm{W} \\ )\^2\\ \\Bigr\]\^2 \\\\ &- \\Bigl\[\\ W\_\\mu\^{+}\\ W\_\\nu\^{-} + W\^{+}\_\\nu\\ W\^{-}\_\\mu + \\left(\\ A\_\\mu\\ \\sin \\theta\_\\mathrm{W} - Z\_\\mu\\ \\cos \\theta\_\\mathrm{W}\\ \\right)\\left(\\ A\_\\nu\\ \\sin \\theta\_\\mathrm{W} - Z\_\\nu\\ \\cos \\theta\_\\mathrm{W}\\ \\right)\\ \\Bigr\]\^2\\,\\Biggr\\} \~. \\end{align}
$\ \mathcal{L}_\mathrm{Y}\$ contains the Yukawa interactions between the fermions and the Higgs field,
: $\mathcal{L}_\mathrm{Y} = -\sum_f\ \frac{\ g\ m_f\ }{2\ m_\mathrm{W}} \; \overline{f}\ f\ H ~
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# Erasmus Reinhold
**Erasmus Reinhold** (22 October 1511 -- 19 February 1553) was a German astronomer and mathematician, considered to be the most influential astronomical pedagogue of his generation. He was born and died in Saalfeld, Saxony.
He was educated, under Jacob Milich, at the University of Wittenberg, where he was first elected dean and later became rector. In 1536 he was appointed professor of higher mathematics by Philipp Melanchthon. In contrast to the limited modern definition, \"mathematics\" at the time also included applied mathematics, especially astronomy. His colleague, Georg Joachim Rheticus, also studied at Wittenberg and was appointed professor of lower mathematics in 1536.
Reinhold catalogued a large number of stars. His publications on astronomy include a commentary (1542, 1553) on Georg Purbach\'s *Theoricae novae planetarum*. Reinhold knew about Copernicus and his heliocentric ideas prior to the publication of his *De revolutionibus*, and made a favourable reference to him in his commentary on Purbach. However, Reinhold (like other astronomers before Kepler and Galileo) translated Copernicus\' mathematical methods back into a geocentric system, rejecting heliocentric cosmology on physical and theological grounds.
Duke Albert of Brandenburg Prussia supported Reinhold and financed the printing of Reinhold\'s *Prutenicae Tabulae* (1551, 1562, 1571, and 1585) or *Prussian Tables*. These astronomical tables helped to disseminate calculation methods of Copernicus throughout the Empire, however, Gingerich notes that they showed a \"notable lack of commitment\" to heliocentricity and were \"carefully framed\" to be independent of the movement of the Earth. Both Reinhold\'s *Prutenic Tables* and Copernicus\' studies were the foundation for the Calendar Reform by Pope Gregory XIII in 1582.
It was Reinhold\'s heavily annotated copy of *De revolutionibus* in the Royal Observatory, Edinburgh, that started Owen Gingerich on his search for copies of the first and second editions which he describes in *The Book Nobody Read*. In Reinhold\'s unpublished commentary on *De revolutionibus*, he calculated the distance from the Earth to the Sun. He \"massaged\" his calculation method in order to arrive at an answer close to that of Ptolemy.
His name has been given to a prominent lunar impact crater that lies to the south-southwest of the crater Copernicus, on the Mare Insularum
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# Ezra Abbot
**Ezra Abbot** (April 28, 1819, Jackson, Maine`{{spaced ndash}}`{=mediawiki}March 21, 1884, Cambridge, Massachusetts) was an American biblical scholar.
## Life and writings {#life_and_writings}
Abbot was born at Jackson, Maine, April 28, 1819; son of Ezra and Phebe Abbot. He was educated at Phillips Exeter Academy and graduated from Bowdoin College in 1840. In 1847, at the request of Andrews Norton, he went to Cambridge, Massachusetts where he was principal of a public school until 1856. He was assistant librarian of Harvard University from 1856 to 1872, and planned and perfected an alphabetical card catalog, combining many of the advantages of the ordinary dictionary catalogs with the grouping of the minor topics under more general heads, which is characteristic of a systematic catalogue. From 1872 until his death he was Bussey Professor of New Testament Criticism and Interpretation in the Harvard Divinity School.
Abbot\'s studies were chiefly in Southwest Asian languages and textual criticism of the New Testament, though his work as a bibliographer showed such results as the exhaustive list of writings (5300 in all) on the doctrine of the future life, appended to William Rounseville Alger\'s *History of the Doctrine of a Future Life, as it has prevailed in all Nations and Ages* (1862), and published separately in 1864.
Abbot\'s publications, though always of the most thorough and scholarly character, were to a large extent dispersed in the pages of reviews, dictionaries, concordances, texts edited by others, Unitarian controversial treatises, etc. However, he took a more conspicuous and personal part in the preparation (with Baptist scholar Horatio Balch Hackett) of the enlarged American edition of Dr. (afterwards Sir) William Smith\'s *Dictionary of the Bible* (1867--1870), to which he contributed more than 400 articles, as well as greatly improving the bibliographical completeness of the work. He was an efficient member of the American revision committee for the Revised Version (1881--1885) of the King James Bible, and helped prepare Caspar René Gregory\'s Prolegomena to the revised Greek New Testament of Constantin von Tischendorf.
He was one of the 32 founding members of the Society of Biblical Literature in 1880.
His principal single work, representing his scholarly method and conservative conclusions, was *The Authorship of the Fourth Gospel: External Evidences* (1880; 2nd ed. by J. H. Thayer, with other essays, 1889), originally a lecture. In spite of the compression due to its form, this work was up to that time probably the ablest defense, based on external evidence, of the Johannine authorship, and certainly the most complete treatment of the relation of Justin Martyr to this gospel.
## Honors
Abbot was elected a Fellow of the American Academy of Arts and Sciences in 1861. Though a layman, he received the degree of S.T.D. from Harvard in 1872, and that of D.D. from Edinburgh in 1884.
## Works
### Books
- \- revised by Ezra Abbot
- --------- (1872). [Memoir of the Controversy Respecting the Three Heavenly Witnesses: I John V. 7](https://books.google
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# Edwin Abbott Abbott
**Edwin Abbott Abbott** `{{post-nominals|country=GBR|FBA}}`{=mediawiki} (20 December 1838 -- 12 October 1926) was an English schoolmaster, theologian, and Anglican priest, best known as the author of the novella *Flatland* (1884).
## Early life and education {#early_life_and_education}
Edwin Abbott Abbott was the eldest son of Edwin Abbott (1808--1882), headmaster of the Philological School, Marylebone, and his wife, Jane Abbott (1806--1882). His parents were first cousins.
He was born in London and educated at the City of London School and at St John\'s College, Cambridge, where he took the highest honours of his class in classics, mathematics and theology, and became a fellow of his college. In particular, he was 1st Smith\'s prizeman in 1861.
## Career
In 1862 he took orders. After holding masterships at King Edward\'s School, Birmingham, he succeeded G. F. Mortimer as headmaster of the City of London School in 1865, at the early age of 26. There, he oversaw the education of future Prime Minister H. H. Asquith. Abbott was Hulsean lecturer in 1876.
He retired in 1889, and devoted himself to literary and theological pursuits. Abbott\'s open-minded inclinations in theology were prominent both in his educational views and in his books. His *Shakespearian Grammar* (1870) is a permanent contribution to English philology. In 1885, he published a life of Francis Bacon. His theological writings include three anonymously published religious romances -- *Philochristus* (1878), where he tried to raise interest in Gospels reading, *Onesimus* (1882), and *Silanus the Christian* (1908).
More weighty contributions are the anonymous theological discussion *The Kernel and the Husk* (1886), *Philomythus* (1891), his book *The Anglican Career of Cardinal Newman* (1892), and his article \"The Gospels\" in the ninth edition of the *Encyclopædia Britannica*, embodying a critical view which caused considerable stir in the English theological world. He also wrote *St Thomas of Canterbury, His Death and Miracles* (1898), *Johannine Vocabulary* (1905), and *Johannine Grammar* (1906).
Abbott also wrote educational textbooks, one being *Via Latina: A First Latin Book* which was published in 1880 and distributed around the world within the education system.
### *Flatland*
*Main article: Flatland* Abbott\'s best-known work is his 1884 novella *Flatland: A Romance of Many Dimensions* which describes a two-dimensional world and explores the nature of dimensions. It has often been categorized as science fiction although it could more precisely be called \"mathematical fiction\".
With the advent of modern science fiction from the 1950s to the present day, *Flatland* has seen a revival in popularity, especially among science fiction and cyberpunk fans. Many works have been inspired by the novella, including novel sequels and short films
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# Emma Abbott
**Emma Abbott** (December 9, 1850 -- January 5, 1891) was an American operatic soprano and impresario known for her pure, clear voice of great flexibility and volume.
## Early life {#early_life}
Emma Abbott was born in 1850 in Chicago, Illinois, the daughter of the struggling Chicago musician Seth Abbott and his wife, Almira (née Palmer). As a child, she and her brother George studied singing, piano, guitar and violin with their father.
The family moved to Peoria, Illinois, Emma was eight years of age when, she made her first appearance on the stage, singing at a concert given in her father\'s office in Peoria. In 1854, Professor Abbott was unable to find a sufficient number of music students to make ends meet and the family suffered from financial problems. To help out, she and George began performing professionally when Emma was nine years old. She made her debut as a guitar player and singer in Peoria, Illinois in 1859, with George on the violin, and was teaching guitar by age thirteen.
## Career
In 1866, she joined an itinerant concert troupe and toured the country. While performing on the road she met and was befriended by Clara Louise Kellogg. Upon hearing Abbott in a concert in Toledo, Kellogg made it a point to meet her and encourage her to pursue an opera career and gave her a letter of introduction. Consequently, Abbott studied in New York City under Achille Errani, and made her concert début there in December 1871.
In 1872, Abbott went abroad to study with Antonio Sangiovanni in Milan. This was followed by further studies with Mathilde Marchesi, Pierre François Wartel and Enrico Delle Sedie in Paris. She appeared in several productions in Paris, earning rave reviews for her fine soprano voice. She was awarded a contract with the Royal Opera in London and made her début at Covent Garden as Marie in *La Fille du régiment* in 1876. However, her contract was cancelled shortly thereafter when she refused to sing Violetta from Verdi\'s *La Traviata* on moral grounds. That same year she secretly married Eugene Wetherell (d. 1889) and they returned to the United States, where she remained for the rest of her life.
### Abbott English Opera Company {#abbott_english_opera_company}
On February 23, 1877, Abbott made her American operatic début in New York, once again portraying Marie. In 1878 she and her husband Eugene Wetherell, organized an opera company known by her name (the Emma Abbott Grand English Opera Company), which toured extensively throughout the United States. It was the first opera company formed by a woman in the United States. Her husband ran the business end of the company and she managed the artistic side, often starring in the productions.
The company garnered a reputation among the public for quality productions and was quite successful. Among the notable roles that Abbott sang with the company are Juliette in Gounod\'s *Roméo et Juliette*, Virginia in *Paul et Virginie*, Josephine in *H.M.S. Pinafore*, the title role in Flotow\'s *Martha*, Amina in Bellini\'s *La Sonnambula*, and Violetta in *La Traviata*, a role to which she apparently no longer objected, however, instead of singing *Addio del passato*, she made Violetta expire with *Nearer, my God, to Thee*.
Throughout her career, she retained artistic control over her troupe, which sometimes numbered 60. Although the company\'s repertoire included works from the French, Italian and English operatic literatures, they always performed in English. Many of the works were abridged and interpolated songs were commonplace. For this reason the company and Abbott were not popular with many music critics who were unhappy with the changes to the standard repertoire. However, the company was incredibly popular with the public and was consistently financially successful. Abbott herself became known among Americans as \'the people\'s prima donna\'.
## Death
Abbott continued performing up until her sudden death from pneumonia in Salt Lake City, Utah in 1891, aged 40. She is buried at Oak Grove Cemetery in Gloucester, Massachusetts along with her husband
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# Emperor Shōmu
was the 45th emperor of Japan, according to the traditional order of succession. Shōmu\'s reign spanned the years 724 through 749, during the Nara period.
## Traditional narrative {#traditional_narrative}
Before his ascension to the Chrysanthemum Throne, his personal name (*imina*) is not clearly known, but he was known as Oshi-hiraki Toyosakura-hiko-no-mikoto.
Shōmu was the son of Emperor Monmu and Fujiwara no Miyako, a daughter of Fujiwara no Fuhito.
Shōmu had five consorts and six Imperial sons and daughters.
### Events of Shōmu\'s reign {#events_of_shōmus_reign}
Shōmu was still a child at the time of his father\'s death; thus, his grandmother, Empress Gemmei, and aunt, Empress Gensho, occupied the throne before he acceded.
- **724** (*Yōrō 8, 1st month*): In the 9th year of Genshō*-tennō*{{\'}}s reign (元正天皇九年), the empress abdicated; and her nephew received the succession (''senso''). Shortly thereafter, Emperor Shōmu is said to have acceded to the throne (''sokui'').
- **January 31, 724** (*Jinki 1*) : The era name is changed to mark the accession of Emperor Shōmu.
- **735--737**: A major smallpox epidemic raged throughout Japan, incurring adult mortality rates of about 25% to 35%.
Shōmu continued to reside in the Hezei Palace.
Shōmu is known as the first emperor whose consort was not born into the imperial household. His consort Kōmyō was a non-royal Fujiwara commoner. A ritsuryō office was created for the queen-consort, the *Kogogushiki*; and this bureaucratic innovation continued into the Heian period.
#### Emperor Shōmu\'s tour to the eastern provinces {#emperor_shōmus_tour_to_the_eastern_provinces}
While battle maneuvers of the Fujiwara no Hirotsugu Rebellion were still underway, in Tenpyō 12 10th month (November, 740) Emperor Shōmu left the capital at Heijō-kyō (Nara) and traveled eastward via Horikoshi (堀越頓宮; today Tsuge; 10th month, 29th day: November 22), Nabari (10th month, 30th day: November 23), Ao (安保頓宮; today Aoyama ; 11th month 1st day: November 24) to Kawaguchi in Ichishi District, Ise Province (today part of Tsu, formerly part of Hakusan) where he retreated together with his court to a temporary palace. One of his generals was left in command of the capital. Presumably Shōmu feared Fujiwara supporters in Nara and was hoping to quell potential uprisings in other parts of the country with his presence. After four days travelling through heavy rain and thick mud, the party reached Kawaguchi on Tenpyō 12 11th month, 2nd day (25 November, 740) A couple of days later, they learn of Hirotsugu\'s execution and that the rebellion had been quelled.
Despite the good news, Shōmu did not return to Heijō-kyō immediately, but stayed in Kawaguchi until Tenpyō 12 11th month, 11th day (4 December, 740). He continued his journey east, then north via Mino Province and back west along the shores of Lake Biwa to Kuni in Yamashiro Province (today in Kizugawa) which he reached on Tenpyō 12 12th month, 15th day (6 January, 741). Places passed along the way included Akasaka (赤坂頓宮; today Suzuka; 11th m. 14th d.: Dec 7）, Asake district (朝明郡; today Yokkaichi; 11th m. 20th d.: Dec 13）, Ishiura (石占頓宮; today Tado; 11th m. 25th d.: Dec 18）, Tagi district (当伎郡; today Yōrō; 11th m. 26th d.: Dec 19）, Fuwa (不破頓宮; today Tarui; 12th m. 1st d.: Dec 23）, Yokokawa (横川頓宮; today Santō or Maihara; 12th m. 6th d.: Dec 28), Inukami (犬上頓宮; today Hikone; 12th m. 7th d.: Dec 29）, Gamō district (蒲生郡; today near Yōkaichi; 12th m. 9th d.: Dec 31）, Yasu (野洲頓宮; today Yasu or Moriyama; 12th m. 10th d.: Jan 1）, Awazu (禾津頓宮; today Ōtsu; 12th m. 11th d.： Jan 2）, Tamanoi (玉井頓宮; today Yamashina-ku, Kyoto; 12th m. 14th d.）. Situated among the hills and near a river north of Nara, Kuni was easily defensible. In addition, the area was linked with the Minister of the Right, Tachibana no Moroe, while Nara was a center of the Fujiwara clan. On Tenpyō 12 12th month, 15 day (6 January, 741) Shōmu proclaimed a new capital at Kuni-kyō.
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# Emperor Shōmu
## Traditional narrative {#traditional_narrative}
### Timeline
- **724** (*Jinki 1*): Emperor Shōmu rises to throne.
- **740** (*Tenpyō 12, 8th month*): In the Imperial court in Nara, Kibi no Makibi and Genbō conspire to discredit Fujiwara no Hirotsugu, who is *Dazai shoni* in Kyushu.
- **740** (*Tenpyō 12, 9th month*): Hirotsugu rebels in reaction to the growing influence of Genbō and others.
- **740** (*Tenpyō 12, 9th month*): Under the command of Ōno no Azumabito, an Imperial army of 17,000 is sent to Kyushu to stop the potential disturbance.
- **740** (*Tenpyō 12, 10th month*): Hirotsugu is decisively beaten in battle; and he is beheaded in Hizen Province.
- **740** (*Tenpyō 12*): The capital is moved to Kuni-kyō
- **741** (*Tenpyō 13*): The Emperor calls for nationwide establishment of provincial temples. Provincial temples (*\"kokubunji\"*) and provincial nunneries (*\"kokubunniji\"*) were established throughout the country. The more formal name for these *\"kokubunji\"* was *\"konkomyo-shitenno-gokoku no tera\"* (meaning \"temples for the protection of the country by the four guardian deities of the golden light\"). The more formal name for these *\"bokubunniji\"* was *\"hokke-metuzai no tera\"* (meaning \"nunneries for eliminating sin by means of the Lotus Sutra\").
- **743** (*Tenpyō 15*): The Emperor issues a rescript to build the *Daibutsu* (Great Buddha), later to be completed and placed in Tōdai-ji, Nara.
- **743** (*Tenpyō 15*): The law of Perpetual Ownership of Cultivated Lands (墾田永代私財法) issued
- **744** (*Tenpyō 16*): In the spring, the court was moved to Naniwa-kyō which then became the new capital.
- **745** (*Tenpyō 17*): The Emperor declares by himself Shigaraki-kyō the capital
- **745** (*Tenpyō 17*): The capital returns to Heijō-kyō, construction of the Great Buddha resumes.
- **749** (*Tenpyō 21, 4th month*): Shōmu, accompanied by the empress, their children, and all the great men and women of the court, went in procession to Todai-ji. The emperor stood before the statue of the Buddha and proclaimed himself to be a disciple of the three jewels, which are the Buddha, the Dharma, and the Sangha.
- **749** (*Tenpyō 21, 7th month*): After a 25-year reign, Emperor Shōmu abdicates in favor of his daughter, Princess Takano, who would become Empress Kōken. After abdication, Shōmu took the tonsure, thus becoming the first retired emperor to become a Buddhist priest. Empress Komyo, following her husband\'s example, also took holy vows in becoming a Buddhist nun.
- **752** (*Tenpyō-shōhō 4, 4th month*): The Eye-Opening Ceremony, presided over by Rōben and celebrating the completion of the Great Buddha, is held at Tōdai-ji.
### Legacy
Shōmu, a devout Buddhist, is best remembered for commissioning, in 743, the sixteen-meter high statue of the Vairocana Buddha (the *Daibutsu*) in Tōdai-ji of Nara. At the time, this was such a massive undertaking that later chroniclers accuse him of having completely exhausted the country\'s reserves of bronze and precious metals. In 752, the Shōmu held the Eye-opening Ceremony of the Great Buddha.
Earlier in 741, he established the system of provincial temples, making this the closest anyone ever came to declaring Japan a Buddhist nation. In addition he commissioned the observance of the ohigan holiday for both spring and autumnal equinox.
Emperor Shōmu died at age 56.
The actual site of Shōmu\'s grave is known. This emperor is traditionally venerated at a memorial Shinto shrine (*misasagi*) at Nara.
The Imperial Household Agency designates this location as Shōmu\'s mausoleum. It is formally named *Sahoyama no minami no misasagi*. The tomb site can be visited today in Horenji-cho, Tenri City near Nara City. The Imperial tomb of Shōmu\'s consort, Empress Kōmyō, is located nearby.
### Shōsōin
The Shōsō-in (正倉院) is the treasure house of Tōdai-ji Temple in Nara, Japan. It houses about 9.000 artifacts connected to Emperor Shōmu (701--756) and Empress Kōmyō (701--760), as well as arts and crafts of the Tempyō era of Japanese history. Its general importance derives from the fact, that it may be called an ark of Tang dynasty period cultural relics from Japan as well as from the continent: furniture, games, music instruments, clothing/accessories, weaponry, buddhist objects and pieces of writing. See main entry.
### Kugyō
is a collective term for the very few most powerful men attached to the court of the Emperor of Japan in pre-Meiji eras.
In general, this elite group included only three to four men at a time. These were hereditary courtiers whose experience and background would have brought them to the pinnacle of a life\'s career. During Shōmu\'s reign, this apex of the *Daijō-kan* included:
- *Daijō-daijin* (720--735), Toneri*-shinnō* (舎人親王) (9th son of Emperor Tenmu).
- *Daijō-daijin* (737--745), Suzuka*-ō* (鈴鹿王) (son of Prince Takechi).
- *Sadaijin* (724--729), Nagaya*-ō* (長屋王) (son of Prince Takechi).
- *Sadaijin* (743--756), Tachibana no Moroe (橘諸兄) (formerly Katsuragi*-ō*, Prince Katsuragi) (half brother of Empress Kōmyō) .
- *Udaijin* (734--737), Fujiwara no Muchimaro (藤原武智麻呂) (son of Fujiwara no Fuhito).
- *Naidaijin*, Fujiwara no Toyonari (藤原豊成) (son of Fujiwara no Muchimaro).
- *Dainagon*, Fujiwara no Fusasaki (藤原房前) (son of Fujiwara no Fuhito).
## Eras of Shōmu\'s life {#eras_of_shōmus_life}
The years of Shōmu\'s reign are more specifically identified by more than one era name or *nengō*.
-
- *Jinki* (724--729)
- *Tenpyō* (729--749)
- *Tenpyō-kanpō* (749)
- *Tenpyō-shōhō* (749--757)
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# Emperor Shōmu
## Consorts and children {#consorts_and_children}
- Empress (Kōgō): Fujiwara Asukabehime (藤原 安宿媛), Fujiwara no Fuhito's daughter
- Second Daughter: Imperial Princess Abe (阿倍内親王) later Empress Kōken
- First Son: Prince Motoi (基王, 727--728)
- *Bunin*: Agatainukai no Hirotoji (県犬養広刀自, d.762), Agatainukai no Morokoshi\'s daughter
- First Daughter: Imperial Princess Inoe (井上内親王), married to Emperor Kōnin
- Third Daughter: Imperial Princess Fuwa (不破内親王, 723--795), married to Prince Shioyaki
- Second Son: Imperial Prince Asaka (安積親王, 728--744)
- *Bunin*: Nan-dono (南殿, d.748), Fujiwara no Muchimaro's daughter
- *Bunin*: Hoku-dono (北殿, d.760), Fujiwara no Fusasaki's daughter
- *Bunin*: Tachibana-no-Hirooka no Konakachi (橘広岡古那可智, d.759), Tachibana no Sai\'s daughter
## Ancestry
`{{ahnentafel
|collapsed=yes |align=center
|boxstyle_1=background-color: #fcc;
|boxstyle_2=background-color: #fb9;
|boxstyle_3=background-color: #ffc;
|boxstyle_4=background-color: #bfc;
|1= 1. '''Emperor Shōmu'''
|2= 2. [[Emperor Monmu]] (683–707)
|3= 3. [[:ja:藤原宮子|Fujiwara no Miyako]] (c. 683–754)
|4= 4. [[Crown Prince Kusakabe]] (662–689)
|5= 5. [[Empress Genmei]] (660–721)
|6= 6. [[Fujiwara no Fuhito]] (659–720)
|7= 7. Kamo no Hime
|8= 8. [[Emperor Tenmu]] (c. 631–686)
|9= 9. [[Empress Jitō]] (645–703)
|10=10. [[Emperor Tenji]] (626–672)
|11=11. [[:ja:姪娘|Mei no Iratsume]]
|12=12. [[Fujiwara no Kamatari]] (614–669)
|13=13. Yoshiko
|14=14
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# Emperor Kanmu
, or **Kammu**, was the 50th emperor of Japan, according to the traditional order of succession. Kammu reigned from 781 to 806, and it was during his reign that the scope of the emperor\'s powers reached its peak. His reign saw the transition from the Nara period to the Heian period.
## Traditional narrative {#traditional_narrative}
Kammu\'s personal name (*imina*) was `{{Nihongo|Yamabe|山部}}`{=mediawiki}. He was the eldest son of Prince Shirakabe (later known as Emperor Kōnin), and was born prior to Shirakabe\'s ascension to the throne. According to the `{{Nihongo|''[[Shoku Nihongi]]''|続日本紀}}`{=mediawiki}, Yamabe\'s mother, Yamato no Niigasa (later called Takano no Niigasa), was a 10th generation descendant of Muryeong of Baekje (462--523).
After his father became emperor, Kammu\'s half-brother, Prince Osabe was appointed to the rank of crown prince. His mother was Princess Inoe, a daughter of Emperor Shōmu; but instead of Osabe, it was Kammu who was later named to succeed their father. After Inoe and Prince Osabe were confined and then died in 775, Osabe\'s sister -- Kammu\'s half-sister Princess Sakahito -- became Kammu\'s wife. Later, when he ascended to the throne in 781, Kammu appointed his young brother, Prince Sawara, whose mother was Takano no Niigasa, as crown prince. Hikami no Kawatsugu, a son of Emperor Tenmu\'s grandson Prince Shioyaki and Shōmu\'s daughter Fuwa, attempted to carry out a coup d\'état in 782, but it failed and Kawatsugu and his mother were sent into exile. In 785 Sawara was expelled and died in exile.
The Nara period saw the appointment of the first *shōgun*, Ōtomo no Otomaro by Emperor Kammu in 794 CE. The shōgun was the military dictator of Japan with near absolute power over territories via the military. Otomaro was declared \"Sei-i Taishōgun\" which means \"Barbarian-subduing Great General\". Emperor Kammu granted the second title of shōgun to Sakanoue no Tamuramaro for subduing the Emishi in northern Honshu.
Kammu had 16 empresses and consorts, and 32 imperial sons and daughters. Among them, three sons would eventually ascend to the imperial throne: Emperor Heizei, Emperor Saga and Emperor Junna. Some of his descendants (known as the *Kammu Taira* or *Kammu Heishi*) took the Taira hereditary clan title, and in later generations became prominent warriors. Examples include Taira no Masakado, Taira no Kiyomori, and (with a further surname expansion) the Hōjō clan. The *waka* poet Ariwara no Narihira was one of his grandsons.
Kammu is traditionally venerated at his tomb; the Imperial Household Agency designates `{{Nihongo3|Kashiwabara Imperial Mausoleum|柏原陵|Kashiwabara no Misasagi}}`{=mediawiki}, in Fushimi-ku, Kyoto, as the location of Kammu\'s mausoleum.
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# Emperor Kanmu
## Traditional narrative {#traditional_narrative}
### Events of Kammu\'s life {#events_of_kammus_life}
Kammu was an active emperor who attempted to consolidate government hierarchies and functions. Kammu appointed Sakanoue no Tamuramaro (758--811) to lead a military expedition against the Emishi.
- **737**: Kammu was born.
- **773**: Received the title of crown prince.
- **April 30, 781**(`{{Nihongo foot|''[[Ten'ō]] 1, 3rd day of the 4th month''|天安一年四月三日}}`{=mediawiki}): In the 11th year of Kōnin\'s reign, he abdicated; and the succession was received by his son Kammu. Shortly thereafter, Emperor Kammu is said to have ascended to the throne. During his reign, the capital of Japan was moved from Nara (Heijō-kyō) to Nagaoka-kyō in 784. Shortly thereafter, the capital would be moved again in 794.
- **July 28, 782** (`{{Nihongo foot|''[[Enryaku]] 1, 14th day of the 6th month''|延暦一年六月十四日}}`{=mediawiki}): The *sadaijin* Fujiwara no Uona was involved in an incident that resulted in his removal from office and exile to Kyushi. Claiming illness, Uona was permitted to return to the capital where he died; posthumously, the order of banishment was burned and his office restored. In the same general time frame, Fujiwara no Tamaro was named Udaijin. During these days in which the offices of *sadaijin* and *udaijin* were vacant, the major counselors (the *dainagon*) and the emperor assumed responsibilities and powers which would have been otherwise delegated.
- **783** (`{{Nihongo foot|''Enryaku 2, 3rd month''|延暦二年三月}}`{=mediawiki}): The *udaijin* Tamaro died at the age of 62 years.
- **783** (`{{Nihongo foot|''Enryaku 2, 7th month''|延暦二年七月}}`{=mediawiki}): Fujiwara no Korekimi became the new *udaijin* to replace the late Fujiwara no Tamaro.
- **793** (`{{Nihongo foot|''Enryaku 12''|延暦十二年}}`{=mediawiki}): Under the leadership of Dengyō, construction began on the Enryaku Temple.
- **794**: The capital was relocated again, this time to Heian-kyō, where the palace was named `{{Nihongo3|"palace of peace/tranquility"|平安宮|Heian no Miya}}`{=mediawiki}.
- **November 17, 794** (`{{Nihongo foot|''Enryaku 13, 21st day of the 10th month''|延暦十三年十月二十一日}}`{=mediawiki}): The emperor traveled by carriage from Nara to the new capital of Heian-kyō in a grand procession. This marks the beginning of the Heian period.
- **794** appointed Ōtomo no Otomaro as the first Shōgun \"Sei-i Taishōgun---\"Barbarian-subduing Great General\", together with Sakanoue no Tamuramaro subdues the Emishi in Northern Honshu.
- **806**: Kammu died at the age of 70. Kammu\'s reign lasted for 25 years.
### Eras of Kammu\'s reign {#eras_of_kammus_reign}
The years of Kammu\'s reign are more specifically identified by more than one era name (*nengō*).
- *Ten\'ō* (781--82)
- *Enryaku* (782--806)
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# Emperor Kanmu
## Politics
### Domestic relations {#domestic_relations}
Earlier Imperial sponsorship of Buddhism, beginning with Prince Shōtoku (574--622), had led to a general politicization of the clergy, along with an increase in intrigue and corruption. In 784 Kammu shifted his capital from Nara to Nagaoka-kyō in a move that was said to be designed to encumber the powerful Nara Buddhist establishments out of state politics---while the capital moved, the major Buddhist temples, and their officials, stayed put. Indeed, there was a steady stream of edicts issued from 771 right through the period of Kūkai\'s studies which, for instance, sought to limit the number of Buddhist priests, and the building of temples. However, the move was to prove disastrous and was followed by a series of natural disasters including the flooding of half the city. In 785 the principal architect of the new capital, and royal favourite, Fujiwara no Tanetsugu, was assassinated.
Meanwhile, Kammu\'s armies were pushing back the boundaries of his empire. This led to an uprising, and in 789 a substantial defeat for Kammu\'s troops. Also in 789 there was a severe drought and famine---the streets of the capital were clogged with the sick, and people avoiding being drafted into the military, or into forced labour. Many disguised themselves as Buddhist priests for the same reason. Consequently, in 792 Kammu abolished national conscription, replacing it with a system wherein each province formed a militia from the local gentry, however this system vitiated the authority of the Emperor and led to proliferation of private armies. Then in 794 Kammu suddenly shifted the capital again, this time to Heian-kyō, which is modern day Kyoto. The new capital was started early the previous year, but the change was abrupt and led to even more confusion amongst the populace. Kammu\'s rule witnessed the frontiers of Japan expanding into Izawa and Shiba, under the command of a preeminent commander, Tamura Maro.
Politically Kammu shored up his rule by changing the syllabus of the university. Confucian ideology still provided the *raison d\'être* for the Imperial government. In 784 Kammu authorised the teaching of a new course based on the *Spring and Autumn Annals* based on two newly imported commentaries: *Kung-yang* and *Ku-liang*. These commentaries used political rhetoric to promote a state in which the Emperor, as \"Son of Heaven,\" should extend his sphere of influence to barbarous lands, thereby gladdening the people. In 798 the two commentaries became required reading at the government university.
Emperor Kanmu was the first person to conceive the *Shinsen Shōjiroku*, a Japanese genealogical record in 799 to properly track the clans\' then ambiguous lineages, but it was not able to be completed before his death in 806. The project was later carried over by his sons and was completed during Emperor Saga\'s reign in 814.
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# Emperor Kanmu
## Politics
### Foreign relations {#foreign_relations}
#### China
Kammu also sponsored the travels of the monks Saichō and Kūkai to China, from where they returned to found the Japanese branches of, respectively, Tendai and Shingon Buddhism.
#### Korea
He was specifically interested in Baekje (and to an extent, Goguryeo) as his mother was of Baekje descent.
Kammu\'s emphasis towards his Baekje heritage became prominent as his mother was not of the Imperial line, but was in fact a royal consort to Emperor Kōnin on top of coming from a clan of foreign (Korean) origin, which could have negatively affected his ascension as emperor and be deemed illegitimate by some. To circumvent this, Kammu focused heavily on the mythological aspects of his mother\'s ancestor, Muryeong of Baekje and Muryeong\'s own ancestor, Dongmyeong of Goguryeo (Ko Chumong), emphasizing Chumong\'s heritage as a grandchild of the god Habaek and Kammu\'s own lineage that continued it claiming that he was part of the \"heavenly lineage\". He mentions this in *Shoku Nihongi* when honoring his late mother.
In 790, Emperor Kanmu issued a rescript that treated the Kudara no Konikishi clan (a fellow Japanese clan of Baekje descent) as \"relatives by marriage\". It was related to the fact that the emperor\'s mother belonged to the Baekje-originated Yamato no Fuhito clan, who then claimed its roots in the Baekje royal family. In addition, according to the Shoku Nihongi, Takano no Niigasa was a 10th-generation descendant of King Muryeong of Baekje through his son Prince Junda (Nihon Shoki, chapter 17), making Emperor Kammu an 11th-generation descendant of Muryeong through maternal lineage. The Kudara no Konikishi clan fell under the influence of the southern branch of the Fujiwara clan after Kudara no Konikishi Myōshin had married Fujiwara no Tsugutada around 754. Emperor Kanmu\'s rescript of 790 aimed to support Myōshin\'s appointment as lady-in-waiting (尚侍), the highest post among court ladies, due to her similar background with Kammu.
A 14th century book called \"*Jinnō Shōtōki*\" by Kitabatake Chikafusa states that a record that claimed of Japan\'s origin with Korea was lost during Kammu\'s time, which indicates that such intentions were highly regarded during Emperor Kanmu\'s reign up until the book\'s disappearance.
It can be deduced that Kammu advocated his Korean ancestry for both political and social reasons at the time, which was later officially recognized by the government coming from the Emperor of Japan.
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# Emperor Kanmu
## Kugyō
is a collective term for the very few most powerful men attached to the court of the Emperor of Japan in pre-Meiji eras.
In general, this elite group included only three to four men at a time. These were hereditary courtiers whose experience and background would have brought them to the pinnacle of a life\'s career. During Kammu\'s reign, this apex of the *Daijō-kan* included:
- *Sadaijin*, Fujiwara no Uona (藤原魚名), 781--82.
- *Sadaijin*, Fujiwara no Tamaro (藤原田麿), 783.
- *Udaijin*, Ōnakatomi no Kiyomaro (大中臣清麿), 771--81
- *Udaijin*, Fujiwara no Tamaro (藤原田麿), 782--83.
- *Udaijin*, Fujiwara no Korekimi (藤原是公), 783--89.
- *Udaijin*, Fujiwara no Tsuginawa (藤原継縄), 790--96.
- *Udaijin*, Miwa ōkimi or Miwa oh (神王), 798--806
- *Udaijin*, Fujiwara no Uchimaro (藤原内麻呂) 756--812, 806--12.
- *Dainagon*
When the daughter of a *chūnagon* became the favored consort of the Crown Prince Ate (later known as Heizei*-tennō*), her father\'s power and position in court was affected. Kammu disapproved of Fujiwara no Kusuko, daughter of Fujiwara no Tanetsugu; and Kammu had her removed from his son\'s household.
- *Chūnagon*, Fujiwara no Tadanushi
## Consorts and children {#consorts_and_children}
Emperor Kammu\'s Imperial family included 36 children.
- Empress (*Kōgō*): Fujiwara no Otomuro (藤原乙牟漏), Fujiwara no Yoshitsugu's daughter
- First Son: Imperial Prince Ate (安殿親王) later Emperor Heizei
- Fourth Son: Imperial Prince Kamino (賀美能親王/神野親王) later Emperor Saga
- Imperial Princess Koshi (高志内親王; 789--809), married to Emperor Junna
- Madame *(Bunin later Kōtaigō)*: Fujiwara no Tabiko (藤原旅子), Fujiwara no Momokawa's daughter
- Fifth Son: Imperial Prince Ōtomo (大伴親王) later Emperor Junna
- *Consort (Hi):* Imperial Princess Sakahito (酒人内親王), Emperor Kōnin's daughter
- First Daughter: Imperial Princess Asahara (朝原内親王; 779--817), 12th *Saiō* in Ise Grand Shrine (782--before 796), and married to Emperor Heizei
- Madame (*Bunin**)*: Fujiwara no Yoshiko (藤原吉子; d.807), Fujiwara no Korekimi's daughter
- Second Son: Imperial Prince Iyo (伊予親王; 783--807)
- Madame *(Bunin)* : Tajihi no Mamune (多治比真宗; 769--823), Tajihi no Nagano\'s daughter
- Sixth Son: Imperial Prince Kazurahara (葛原親王; 786--853)
- Ninth Son: Imperial Prince Sami (佐味親王; 793--825)
- Tenth Son: Imperial Prince Kaya (賀陽親王; 794--871)
- Imperial Prince Ōno (大野親王/大徳親王; 798--803)
- Imperial Princess Inaba (因幡内親王; d.824)
- Imperial Princess Anou (安濃内親王; d.841)
- Madame *(Bunin)*: Fujiwara no Oguso (藤原小屎), Fujiwara no Washitori\'s daughter
- Third Son: Imperial Prince Manta (万多親王; 788--830)
- Court Lady *(Nyōgo)* : Ki no Otoio (紀乙魚; d.840), Ki no Kotsuo\'s daughter
- Court Lady *(Nyōgo)* : Kudarao no Kyōhō (百済王教法; d.840), Kudara no Shuntetsu\'s daughter
- Court Lady *(Nyōgo)* : Tachibana no Miiko (橘御井子), daughter of Tachibana no Irii (橘入居)
- Imperial Princess Sugawara (菅原内親王; d.825)
- Sixteenth Daughter: Imperial Princess Kara (賀楽内親王; d.874)
- Court Lady *(Nyōgo)* : Fujiwara no Nakako (藤原仲子), Fujiwara no Ieyori\'s daughter
- Court Lady (*Nyōgo*) : Tachibana no Tsuneko (橘常子; 788--817), Tachibana no Shimadamaro\'s daughter
- Ninth Daughter: Imperial Princess Ōyake (大宅内親王; d.849), married to Emperor Heizei
- Court Lady *(Nyōgo)*: Fujiwara no *Shōshi* (藤原正子), Fujiwara no Kiyonari\'s daughter
- Court Lady *(Nyōgo)*: Sakanoue no Matako (坂上全子, d.790), Sakanoue no Karitamaro\'s daughter
- Twelfth Daughter: Imperial Princess Takatsu (高津内親王; d.841), married to Emperor Saga
- Court Lady *(Nyōgo)*: Sakanoue no Haruko (坂上春子, d.834), Sakanoue no Tamuramaro\'s daughter
- Twelfth Son: Imperial Prince Fujii (葛井親王; 800--850)
- Imperial Princess Kasuga (春日内親王; d.833)
- Court Lady *(Nyōgo)*: Fujiwara no Kawako (藤原河子, d.838), Fujiwara no Ōtsugu\'s daughter
- Thirteenth Son: Imperial Prince Nakano (仲野親王; 792--867)
- Thirteenth Princess: Imperial Princess Ate (安勅内親王; d.855)
- Imperial Princess Ōi (大井内親王; d.865)
- Imperial Princess Ki (紀内親王; 799--886)
- Imperial Princess Yoshihara (善原内親王; d.863)
- Court Lady *(Nyōgo)*: Fujiwara no Azumako (藤原東子, d.816), Fujiwara no Tanetsugu\'s daughter
- Imperial Princess Kannabi (甘南備内親王, 800--817), Married to Emperor Heizei
- Court Lady *(Nyōgo)*: Fujiwara no *Heishi/Nanshi* (藤原平子/南子, d.833), Fujiwara no Takatoshi\'s daughter
- Eighth Daughter: Imperial Princess Ito (伊都内親王), married to Prince Abo
- Court Lady *(Nyōgo)*: Ki no Wakako (紀若子), Ki no Funamori\'s daughter
- Seventh Son: Imperial Prince Asuka (明日香親王, d.834)
- Court Lady *(Nyōgo)*: Fujiwara no Kamiko (藤原上子), Fujiwara no Oguromaro\'s daughter
- Imperial Princess Shigeno (滋野内親王, 809--857)
- Court Lady *(Nyōgo)*: Tachibana no Tamurako (橘田村子), Tachibana no Irii\'s daughter
- Imperial Princess Ikenoe (池上内親王, d.868)
- Court Lady *(Nyōgo)*: Kawakami no Manu (河上好), Nishikibe no Haruhito\'s daughter
- Imperial Prince Sakamoto (坂本親王, 793--818)
- Court Lady (*Nyōgo*): Kudarao no Kyōnin (百済王教仁), Kudara no Bukyō\'s daughter
- Imperial Prince Ōta (大田親王, d.808)
- Court Lady (*Nyōgo*): Kudarao no Jōkyō (百済王貞香), Kudara no Kyōtoku\'s daughter
- Imperial Princess Suruga (駿河内親王, 801--820)
- Court Lady (*Nyōgo*): Nakatomi no Toyoko (中臣豊子), Nakatomi no Ōio\'s daughter
- Fifth Daughter: Imperial Princess Fuse (布勢内親王, d.812), 13th Saiō in Ise Shrine, 797--806
- Court lady (*Nyoju*): Tajihi no Toyotsugu (多治比豊継), Tajihi no Hironari\'s daughter
- Nagaoka no Okanari (長岡岡成, d.848), removed from the Imperial Family by receiving the family name from Emperor (Shisei Kōka, 賜姓降下) in 787
- Court Lady (*Nyoju*):: Kudara no Yōkei (百済永継), Asukabe no Natomaro\'s daughter
- Yoshimine no Yasuyo (良岑安世, 785--830), removed from the Imperial Family by receiving the family name from Emperor (Shisei Kōka, 賜姓降下) in 802
## Ancestry
`{{ahnentafel
|collapsed=yes |align=center
|boxstyle_1=background-color: #fcc;
|boxstyle_2=background-color: #fb9;
|boxstyle_3=background-color: #ffc;
|boxstyle_4=background-color: #bfc;
|1= 1. '''Emperor Kanmu'''
|2= 2. [[Emperor Kōnin]] (709–82)
|3= 3. [[Takano no Niigasa]] (c. 720–90)
|4= 4. [[:ja:志貴皇子|Prince Shiki]] (d. 716)
|5= 5. [[:ja:紀橡姫|Ki no Tochihime]] (d. 709)
|6= 6. Yamato no Ototsugu
|7= 7. Haji no Maimo
|8= 8. [[Emperor Tenji]] (626–72)
|9= 9. Koshi-no-michi no Iratsume
|10=10. [[:ja:紀諸人|Ki no Morohito]]
|11=11. Michi
|12=
|13=
|14=
|15=
}}`{=mediawiki}
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# Emperor Kanmu
## Legacy
In 2001, Japan\'s emperor Akihito told reporters \"I, on my part, feel a certain kinship with Korea\", given the fact that it is recorded in the *Chronicles of Japan* that the Emperor Kammu\'s mother was one of the descendant of King Muryong of Baekje (462--523). It was the first time that a Japanese emperor publicly referred to any Korean ancestry in the imperial line. According to the *Shoku Nihongi*, Emperor Kammu\'s mother, Takano no Niigasa (720--90), is a descendant of Prince Junda, son of Muryeong, who died in Japan in 513 (*Nihon Shoki*, Chapter 17)
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# Electromagnetic spectrum
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# Erinyes
thumb\|upright=1.2\|Clytemnestra tries to awaken the sleeping Erinyes. Detail from an Apulian red-figure bell-krater, 380--370 BC. `{{Greek underworld}}`{=mediawiki} `{{Contains special characters |special=[[Linear B Syllabary|Linear B Unicode characters]] |fix=Help:Multilingual_support#Linear B |characters=Linear B}}`{=mediawiki}
The **Erinyes** (`{{IPAc-en|ɪ|ˈ|r|ɪ|n|i|.|iː|z}}`{=mediawiki} `{{respell|ih|RI|nee|eez}}`{=mediawiki}; *Ἐρινύες\]\]*, `{{singular}}`{=mediawiki} *Ἐρινύς* *Erinys*), also known as the **Eumenides** (*Εὐμενίδες*, the \"Gracious ones\"), are chthonic goddesses of vengeance in ancient Greek religion and mythology. A formulaic oath in the *Iliad* invokes them as \"the Erinyes, that under earth take vengeance on men, whosoever hath sworn a false oath\". Walter Burkert suggests that they are \"an embodiment of the act of self-cursing contained in the oath\". Their Roman counterparts are the **Furies**, also known as the **Dirae**. The Roman writer Maurus Servius Honoratus (c. 400 AD) wrote that they are called \"Eumenides\" in hell, \"Furiae\" on Earth, and \"Dirae\" in heaven. Erinyes are akin to some other Greek deities, called Poenai.
According to Hesiod\'s *Theogony*, when the Titan Cronus castrated his father, Uranus, and threw his genitalia into the sea, the Erinyes (along with the Giants and the Meliae) emerged from the drops of blood which fell on the Earth (Gaia), while Aphrodite was born from the crests of sea foam. Apollodorus also reports this lineage. According to variant accounts they are the daughters of Nyx (\'Night\'), while in Virgil\'s *Aeneid*, they are daughters of Pluto and Nox (the Roman name for Nyx). In some accounts, they were the daughters of Eurynome (a name for Earth) and Cronus, or of Earth and Phorcys (i.e. the sea). In Orphic literature, they are the daughters of Hades and Persephone.
Their number is usually left indeterminate. Virgil, probably working from an Alexandrian source, recognized three: Alecto or Alekto (\"endless anger\"), Megaera (\"jealous rage\"), and Tisiphone or Tilphousia (\"vengeful destruction\"), all of whom appear in the *Aeneid*. Dante Alighieri followed Virgil in depicting the same three-character triptych of Erinyes; in Canto IX of the *Inferno,* they confront the poets at the gates of the city of Dis. Whilst the Erinyes were usually described as three maiden goddesses, \"Telphousia\" (a name for Erinys) was a byname for the wrathful goddess Demeter, who was worshipped under the title of Erinys in the Arcadian town of Thelpusa.
## Etymology
The word *Erinyes* is of uncertain etymology; connections with the verb ὀρίνειν *orinein*, \"to raise, stir, excite\", and the noun ἔρις *eris*, \"strife\" have been suggested; Robert Beekes suggests that the word probably has a Pre-Greek origin. The word *Erinys* in the singular and as a theonym is first attested in Mycenaean Greek, written in Linear B, in the following forms: *𐀁𐀪𐀝}}*, *e-ri-nu*, and *𐀁𐀪𐀝𐀸}}*, *e-ri-nu-we*. These words are found on the KN Fp 1, KN V 52, and KN Fh 390 tablets.
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# Erinyes
## Description
The Erinyes live in Erebus and are more ancient than any of the Olympian deities. Their task is to hear complaints brought by mortals against the insolence of the young to the aged, of children to parents, of hosts to guests, and of householders or city councils to suppliants---and to punish such crimes by hounding culprits relentlessly. The appearance of the Erinyes differs between sources, though they are frequently described as wearing black. In Aesychlus\' *Eumenides,* the Priestess of Pythian Apollo compares their monstrosity to that of the gorgon and harpies, but adds that they are wingless, with hatred dripping from their eyes. Euripides, on the other hand, gives them wings, as does Virgil. They are often envisaged as having snakes in their hair.
The Erinyes are commonly associated with night and darkness. With varying accounts claiming that they are the daughters of Nyx, the goddess of night, they\'re also associated with darkness in the works of Aeschylus and Euripides in both their physical appearance and the time of day that they manifest.
Description of Tisiphone in Statius\' Thebaid:
> So prayed he, and the cruel goddess turned her grim visage to hearken. By chance she sat beside dismal Cocytus, and had loosed the snakes from her head and suffered them to lap the sulphurous waters. Straightway, faster than fire of Jove or falling stars she leapt up from the gloomy bank: the crowd of phantoms gives way before her, fearing to meet their queen; then, journeying through the shadows and the fields dark with trooping ghosts, she hastens to the gate of Taenarus, whose threshold none may cross and again return. Day felt her presence, Night interposed her pitchy cloud and startled his shining steeds; far off towering Atlas shuddered and shifted the weight of heaven upon his trembling shoulders. Forthwith rising aloft from Malea's vale she hies her on the well-known way to Thebes: for on no errand is she swifter to go and to return, not kindred Tartarus itself pleases her so well. A hundred horned snakes erect shaded her face, the thronging terror of her awful head; deep within her sunken eyes there glows a light of iron hue, as when Atracian spells make travailing Phoebe redden through the clouds; suffused with venom, her skin distends and swells with corruption; a fiery vapour issues from her evil mouth, bringing upon mankind thirst unquenchable and sickness and famine and universal death. From her shoulders falls a stark and grisly robe, whose dark fastenings meet upon her breast: Atropos and Proserpine herself fashion her this garb anew. Then both her hands are shaken in wrath, the one gleaming with a funeral torch, the other lashing the air with a live water-snake.
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# Erinyes
## Cult
Pausanias describes a sanctuary in Athens dedicated to the Erinyes under the name Semnai:
> Hard by \[the Areopagos the murder court of Athens\] is a sanctuary of the goddesses which the Athenians call the August, but Hesiod in the Theogony calls them Erinyes (Furies). It was Aeschylus who first represented them with snakes in their hair. But on the images neither of these nor of any of the under-world deities is there anything terrible. There are images of Pluto, Hermes, and Earth, by which sacrifice those who have received an acquittal on the Hill of Ares; sacrifices are also offered on other occasions by both citizens and aliens.
The *Orphic Hymns*, a collection of 87 religious poems as translated by Thomas Taylor, contains two stanzas regarding the Erinyes. Hymn 68 refers to them as the Erinyes, while hymn 69 refers to them as the Eumenides.
**Hymn 68, to the Erinyes:**
> Vociferous Bacchanalian Furies \[Erinyes\], hear! Ye, I invoke, dread pow\'rs, whom all revere; Nightly, profound, in secret who retire, Tisiphone, Alecto, and Megara dire: Deep in a cavern merg\'d, involv\'d in night, near where Styx flows impervious to the sight; Ever attendant on mysterious rites, furious and fierce, whom Fate\'s dread law delights; Revenge and sorrows dire to you belong, hid in a savage veil, severe and strong, Terrific virgins, who forever dwell endu\'d with various forms, in deepest hell; Aerial, and unseen by human kind, and swiftly coursing, rapid as the mind. In vain the Sun with wing\'d refulgence bright, in vain the Moon, far darting milder light, Wisdom and Virtue may attempt in vain; and pleasing, Art, our transport to obtain Unless with these you readily conspire, and far avert your all-destructive ire. The boundless tribes of mortals you descry, and justly rule with Right\'s \[Dike\'s\] impartial eye. Come, snaky-hair\'d, Fates \[Moirai\] many-form\'d, divine, suppress your rage, and to our rites incline.
**Hymn 69, to the Eumenides:**
> Hear me, illustrious Furies \[Eumenides\], mighty nam\'d, terrific pow\'rs, for prudent counsel fam\'d; Holy and pure, from Jove terrestrial \[Zeus Khthonios\](Hades) born and Proserpine \[Phersephone\], whom lovely locks adorn: Whose piercing sight, with vision unconfin\'d, surveys the deeds of all the impious kind: On Fate attendant, punishing the race (with wrath severe) of deeds unjust and base. Dark-colour\'d queens, whose glittering eyes, are bright with dreadful, radiant, life-destroying, light: Eternal rulers, terrible and strong, to whom revenge, and tortures dire belong; Fatal and horrid to the human sight, with snaky tresses wand\'ring in the night; Either approach, and in these rites rejoice, for ye, I call, with holy, suppliant voice.
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# Erinyes
## In ancient Greek literature {#in_ancient_greek_literature}
thumb\|upright=1.3\|Orestes at Delphi, flanked by Athena and Pylades, among the Erinyes and priestesses of the oracle. Paestan red-figure bell-krater, c. 330 BC.
Myth fragments dealing with the Erinyes are found among the earliest extant records of ancient Greek culture. The Erinyes are featured prominently in the myth of Orestes, which recurs frequently throughout many works of ancient Greek literature.
### Aeschylus
Featured in ancient Greek literature, from poems to plays, the Erinyes form the Chorus and play a major role in the conclusion of Aeschylus\'s dramatic trilogy the *Oresteia*. In the first play, *Agamemnon*, King Agamemnon returns home from the Trojan War, where he is slain by his wife, Clytemnestra, who wants vengeance for her daughter Iphigenia, whom Agamemnon had sacrificed to obtain favorable winds to sail to Troy. In the second play, *The Libation Bearers*, their son Orestes has reached manhood and has been commanded by Apollo\'s oracle to avenge his father\'s murder at his mother\'s hand. Returning home and revealing himself to his sister Electra, Orestes pretends to be a messenger bringing the news of his own death to Clytemnestra. He then slays his mother and her lover Aegisthus. Although Orestes\' actions were what Apollo had commanded him to do, Orestes has still committed matricide, a grave sacrilege. Because of this, he is pursued and tormented by the terrible Erinyes, who demand yet further blood vengeance.
In *The Eumenides*, Orestes is told by Apollo at Delphi that he should go to Athens to seek the aid of the goddess Athena. In Athens, Athena arranges for Orestes to be tried by a jury of Athenian citizens, with her presiding. The Erinyes appear as Orestes\' accusers, while Apollo speaks in his defense. The trial becomes a debate about the necessity of blood vengeance, the honor that is due to a mother compared to that due to a father, and the respect that must be paid to ancient deities such as the Erinyes compared to the newer generation of Apollo and Athena. The jury vote is evenly split. Athena participates in the vote and chooses for acquittal. Athena declares Orestes acquitted because of the rules she established for the trial. Despite the verdict, the Erinyes threaten to torment all inhabitants of Athens and to poison the surrounding countryside. Athena, however, offers the ancient goddesses a new role, as protectors of justice, rather than vengeance, and of the city. She persuades them to break the cycle of blood for blood (except in the case of war, which is fought for glory, not vengeance). While promising that the goddesses will receive due honor from the Athenians and Athena, she also reminds them that she possesses the key to the storehouse where Zeus keeps the thunderbolts that defeated the other older deities. This mixture of bribes and veiled threats satisfies the Erinyes, who are then led by Athena in a procession to their new abode. In the play, the \"Furies\" are thereafter addressed as \"Semnai\" (Venerable Ones), as they will now be honored by the citizens of Athens and ensure the city\'s prosperity.
### Euripides
In Euripides\' *Orestes* the Erinyes are for the first time \"equated\" with the \'Eumenides\' (Εὐμενίδες, pl. of Εὐμενίς; literally \"the gracious ones\", but also translated as \"Kindly Ones\"). This is because it was considered unwise to mention them by name (for fear of attracting their attention); the ironic name is similar to how Hades, god of the dead is styled Pluton, or Pluto, \"the Rich One\". Using euphemisms for the names of deities serves many religious purposes
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# Marquess of Aberdeen and Temair
**Marquess of Aberdeen and Temair**, in the County of Aberdeen, in the County of Meath and in the County of Argyll, is a title in the Peerage of the United Kingdom. It was created on 4 January 1916 for John Hamilton-Gordon, 7th Earl of Aberdeen.
## Family history {#family_history}
### Baronetcy of Haddo {#baronetcy_of_haddo}
The Gordon family descends from John Gordon, who fought as a Royalist against the Covenanters in the Civil War. In 1642 he was created a baronet, of Haddo in the County of Aberdeen, in the Baronetage of Nova Scotia. In 1644 he was found guilty of treason and beheaded, with the baronetcy forfeited. The title was restored after the Restoration for his son John, the second Baronet.
### Earldom of Aberdeen {#earldom_of_aberdeen}
The second Baronet died without male issue and was succeeded by his younger brother, the third Baronet. He was a noted advocate and served as Lord President of the Court of Session and as Lord Chancellor of Scotland. On 30 November 1682 he was raised to the Peerage of Scotland as **Lord Haddo, Methlick, Tarves and Kellie**, **Viscount of Formartine** and **Earl of Aberdeen**. He was succeeded by his only surviving son, the second Earl. He sat in the House of Lords as a Scottish representative peer from 1721 to 1727. On his death the titles passed to his eldest son from his second marriage, the third Earl. He was a Scottish Representative Peer from 1747 to 1761 and from 1774 to 1790.
### Lord Aberdeen, Prime Minister {#lord_aberdeen_prime_minister}
The third earl was succeeded by his grandson, the fourth Earl, who was the eldest son of George Gordon, Lord Haddo. On 1 June 1814 he was created **Viscount Gordon**, of Aberdeen in the County of Aberdeen, in the Peerage of the United Kingdom, which entitled him to an automatic seat in the House of Lords. Lord Aberdeen was a distinguished diplomat and statesman and served as Foreign Secretary from 1828 to 1830 and from 1841 to 1846 and as Prime Minister of the United Kingdom from 1852 to 1855. Aberdeen married firstly Lady Catherine Elizabeth (1784--1812), daughter of John Hamilton, 1st Marquess of Abercorn, and assumed by Royal licence the additional surname of Hamilton in 1818.
When Lord Aberdeen died, the titles passed to his eldest son from his second marriage to Harriet Douglas, the fifth Earl. He sat as Liberal member of parliament (MP) for Aberdeenshire. His eldest son, the sixth Earl, was a sailor and adventurer. He was accidentally drowned off the coast of America in 1870, without marrying or having children.
### Marquess of Aberdeen and Temair {#marquess_of_aberdeen_and_temair}
The sixth earl of Aberdeen was succeeded by his younger brother, the seventh Earl. John Hamilton-Gordon, was a Liberal politician and served as Lord-Lieutenant of Ireland in 1886 and from 1905 to 1915 and as Governor General of Canada from 1893 to 1898. On 4 January 1916 he was created **Earl of Haddo**, in the County of Aberdeen, and **Marquess of Aberdeen and Temair**, in the County of Aberdeen, in the County of Meath and in the County of Argyll. Both titles are in the Peerage of the United Kingdom.
He was succeeded by his eldest son, the second Marquess, who was a member of the London County Council and served as Lord-Lieutenant of Aberdeenshire. He was childless and was succeeded by his younger brother, the third Marquess. He was notably President of the Federation of British Industries. When he died the titles passed to his eldest son, the fourth Marquess. He was a member of the Aberdeenshire County Council and Lord-Lieutenant of Aberdeenshire. He had four adopted children but no biological issue and was succeeded by his younger brother, the fifth Marquess.`{{page needed|date=January 2023}}`{=mediawiki} He was a broadcaster working for the BBC. He never married and on his death in 1984 the titles passed to his fourth and youngest brother, the sixth Marquess. He was Chairman of The Arts Club.`{{page needed|date=January 2023}}`{=mediawiki} Upon his death in 2002, the seventh Marquess, who was a Deputy Lieutenant of Aberdeenshire, inherited the titles. `{{As of|2020}}`{=mediawiki}, the Marquessate is held by George Gordon, who is the eighth Marquess of Aberdeen and Temair, having succeeded in that year.
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# Marquess of Aberdeen and Temair
## Family history {#family_history}
### Other family members {#other_family_members}
Numerous other members of the Gordon family have also gained distinction. The Hon. William Gordon (died 1816), eldest son from the third marriage of the second Earl, was a general in the Army. The Hon. Cosmo Gordon, second son from the third marriage of the second Earl, was a colonel in the Army. The Hon. Alexander Gordon (1739--1792), third son from the third marriage of the second Earl, was a Lord of Session from 1788 to 1792 under the judicial title of Lord Rockville. His son William Duff-Gordon was member of parliament for Worcester. In 1815 he succeeded his uncle as second Baron of Halkin according to a special remainder and assumed the additional surname of Duff (see Duff-Gordon baronets for further history of this branch of the family). The Hon. William Gordon, younger brother of the fourth Earl, was a vice-admiral in the Royal Navy and sat as member of parliament for Aberdeenshire. The Hon. Alexander Gordon (1786--1815), younger brother of the fourth Earl, was a soldier and was killed at the Battle of Waterloo.
The Hon. Sir Robert Gordon, younger brother of the fourth Earl, was a diplomat and served as British Ambassador to Austria. The Hon. John Gordon (1792--1869), younger brother of the fourth Earl, was an admiral in the Royal Navy. The Hon. Sir Alexander Hamilton-Gordon (1817--1890), eldest son of the second marriage of the fourth Earl, was a general in the Army and sat as member of parliament for Aberdeenshire East. His eldest son, Sir Alexander Hamilton-Gordon was also a general in the Army. Reverend the Hon. Douglas Hamilton-Gordon (1824--1901), third son of the second marriage of the fourth Earl, was Chaplain-in-Ordinary to Queen Victoria and Canon of Salisbury. The Hon. Arthur Hamilton-Gordon, fourth son of the second marriage of the fourth Earl, was a Liberal politician and was created Baron Stanmore in 1893 (see this title for more information on him and this branch of the family). Ishbel Hamilton-Gordon, Marchioness of Aberdeen and Temair, daughter of Dudley Marjoribanks, 1st Baron Tweedmouth, and wife of the first Marquess of Aberdeen and Temair, was an author, philanthropist and an advocate of woman\'s interests.
The family seat is Haddo House, Aberdeenshire. The title Earl of Haddo is the courtesy title for the Marquess\'s eldest son and heir, the eldest son of whom uses the courtesy title Viscount of Formartine. The Marquesses of Aberdeen and Temair are related to the Marquesses of Huntly. Sir John Gordon (died c. 1395) of Strathbogie, ancestor of Sir John Gordon, 1st Baronet, was the brother of Elizabeth Gordon. She married Sir Alexander Seton (died 1438) and was the mother of Alexander Gordon, 1st Earl of Huntly (ancestor of the Marquesses of Huntly).
## Gordon baronets, of Haddo (1642) {#gordon_baronets_of_haddo_1642}
- Sir John Gordon, 1st Baronet (1610--1644)
- Sir John Gordon, 2nd Baronet (c. 1632--1665)
- Sir George Gordon, 3rd Baronet (1637--1720) (created **Earl of Aberdeen** in 1682)
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# Marquess of Aberdeen and Temair
## Earls of Aberdeen (1682) {#earls_of_aberdeen_1682}
: *Other titles (1st Earl onwards): Viscount of Formartine (Sc 1682), Lord Haddo, Methlick, Tarves and Kellie (Sc 1682)*
: *Other titles (4th Earl onwards): Viscount Gordon (UK 1814)*
- George Gordon, 1st Earl of Aberdeen (1637--1720)
- George Gordon, Lord Haddo (1674-d. between 1694 and 1708)
- William Gordon, 2nd Earl of Aberdeen (1679--1745)
- George Gordon, 3rd Earl of Aberdeen, (1722--1801)
- George Gordon, Lord Haddo (1764--1791)
- George Hamilton-Gordon, 4th Earl of Aberdeen (1784--1860) (created **Viscount Gordon** in 1814)
- George John James Hamilton-Gordon, 5th Earl of Aberdeen (1816--1864)
- George Hamilton-Gordon, 6th Earl of Aberdeen (1841--1870)
- John Campbell Hamilton-Gordon, 7th Earl of Aberdeen (1847--1934) (created **Marquess of Aberdeen and Temair** in 1916)
## Marquesses of Aberdeen and Temair (1916) {#marquesses_of_aberdeen_and_temair_1916}
: *Other titles (1st Marquess onwards): Earl of Haddo (UK 1916), Viscount Gordon (UK 1814), Viscount of Formartine (Sc 1682), Lord Haddo, Methlick, Tarves and Kellie (Sc 1682)*
- John Campbell Gordon, 1st Marquess of Aberdeen and Temair, (1847--1934)
- George Gordon, 2nd Marquess of Aberdeen and Temair (1879--1965)
- Dudley Gladstone Gordon, 3rd Marquess of Aberdeen and Temair (1883--1972)
- David George Ian Alexander Gordon, 4th Marquess of Aberdeen and Temair (1908--1974)
- Archibald Victor Dudley Gordon, 5th Marquess of Aberdeen and Temair (1913--1984)
- Alastair Ninian John Gordon, 6th Marquess of Aberdeen and Temair (1920--2002)
- Alexander George Gordon, 7th Marquess of Aberdeen and Temair (1955--2020)
- George Ian Alastair Gordon, 8th Marquess of Aberdeen and Temair (b. 1983)
## Present peer {#present_peer}
George Ian Alastair Gordon, 8th Marquess of Aberdeen and Temair (born 4 May 1983) is the son of the 7th Marquess and his wife Joanna Clodagh Houldsworth. Styled formally as Viscount Formartine from 1984, he was educated at Harrow School.
He was styled as Earl of Haddo between 2002 and 12 March 2020, when he succeeded his father as Marquess of Aberdeen and Temair, Earl of Haddo, Earl of Aberdeen, Viscount of Formartine, Viscount Gordon of Aberdeen, Lord Haddo, Methlick, Tarves and Kellie, and also as a baronet (Gordon, of Haddo, Aberdeenshire, 1642).
As Lord Haddo he married Isabelle Coaten, daughter of David Coaten, and they have four children
- Ivo Alexander Ninian Gordon, Earl of Haddo (born 2012), heir apparent
- Lord Johnny David Nehemiah Gordon (born 2014)
- Lady Christabel Alexandra Lully Gordon (born 2016)
- Lord Louis George Solomon Gordon (born 2018)
## Succession and family tree {#succession_and_family_tree}
- *Alexander George Gordon, 7th Marquess of Aberdeen and Temair* (1955--2020)
- **George Ian Alastair Gordon, 8th Marquess of Aberdeen and Temair** (born 1983)
- **(1)** Ivo Alexander Ninian Gordon, *Earl of Haddo* (born 2012)
- **(2)** *Lord* Johnny David Nehemiah Gordon (born 2014)
- **(3)** *Lord* Louis George Solomon Gordon (born 2018)
- **(4)** *Lord* Sam Dudley Gordon (born 1985)
- **(5)** Bertie Raiph Dudley Gordon (born 2016)
- **(6)** *Lord* Charles David Gordon (born 1990)
There are further heirs to the subsidiary Earldom of Aberdeen, including the Duff-Gordon baronets, who are descended from Lord Rockville, a younger son of the second earl
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# Eusebius of Alexandria
**Eusebius of Alexandria** (*Εὐσέβιος*) was a 6th-century Christian author to whom certain extant homilies are attributed.
## Biography
Nothing is known of the author. In all events, he was not a patriarch of Alexandria, as is affirmed in an early biography,`{{clarify|what is "MPG"?|date=February 2013}}`{=mediawiki} written by one Johannes, a notary, and stating that Eusebius was called by Cyril to be his successor in the episcopate.
There has been much dispute regarding the details of his life and the age in which he lived. Galland (Vet. Patr. Biblioth., VIII, 23) says: \"de Eusebio qui vulgo dicitur episcopus Alexandræ incerta omnia\" (Concerning Eusebius, commonly called bishop of Alexandria there is nothing sure). His writings have been attributed to Eusebius of Emesa, Eusebius of Cæsarea, and others. According to an old biography said to have been written by his notary, the monk John, and discovered by Cardinal Mai, he lived in the fifth century and led a monastic life near Alexandria. The fame of his virtues attracted the attention of Cyril, Bishop of Alexandria, who visited him with his clergy, and in 444, when dying, had him elected his successor, and consecrated him bishop, though much against his will. Eusebius displayed great zeal in the exercise of his office and did much good by his preaching. Among those he converted was a certain Alexander, a man of senatorial rank. After having ruled his see for seven or, according to another account, for twenty years, he made Alexander his successor and retired to the desert, whence Cyril had summoned him and there died in the odor of sanctity.
While Mai seems to have established the existence of a Eusebius of Alexandria who lived in the fifth century, it had been objected than neither the name of Eusebius or his successor Alexander, appears in the list of the occupants of that ancient see. Dioscurus is mentioned as the immediate successor of Cyril. Nor does the style of the homilies seem on the whole in keeping with the age of Cyril. It may be noted, however, that the biographer of Eusebius expressly states that the Cyril in question is the great opponent of Nestorius. Various solution of the difficulty have been proposed. Thilo thinks that the authorship of the homilies is to be assigned either to a certain monk -- one of four brothers 3 of the fifth century, or to a presbyter and court chaplain of Justinian I, who took an active part in the theological strifes of the sixth century. Mai suggests that after the death of Cyril, there were two bishops at Alexandria, Dioscurus, the Monophysite leader, and Eusebius, the head of the Catholic party. The homilies cover a variety of subjects, and the author is one of the earliest patristic witnesses to the doctrine regarding the descent of Christ into Hell. A list of homilies with the complete text is given by Mai. They may also be found in Migne, which was published with an introduction by Rand in \"Modern Philology\", II, 261.
## Works
These homilies enjoyed some renown in the Eastern Church in the sixth and seventh centuries.
The discourses belong probably to the fifth or sixth century, and possibly originated in Alexandria. They deal with the life of Jesus of Nazareth and with questions of ecclesiastical life and practise, which they resolve in a monastic-ascetic way. Their literary character is not quite clear; while most of them are adapted for public delivery, not a few bear the character of ecclesiastical pronouncements. They are now in print except four included among John Chrysostom\'s works. The fragments preserved in the so-called *Sacra parallela* are to be found in Karl Holl\'s *Fragmente vornicänischer Kirchenväter.*`{{clarify|what is "T U?"|date=February 2013}}`{=mediawiki} A homily concerning the observance of Sunday is attributed by Zahn`{{clarify|Gordon Zahn??|date=February 2013}}`{=mediawiki} to Eusebius of Emesa
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# Estampie
The **estampie** (*estampie*, Occitan and *estampida*, *istanpitta*) is a medieval dance and musical form which was a popular instrumental and vocal form in the 13th and 14th centuries. The name was also applied to poetry.
## Musical form {#musical_form}
The estampie is similar in form to the lai, consisting of a succession of repeated notes. According to Johannes de Grocheio, there were both vocal and instrumental estampies (for which he used the Latin calque \"stantipes\"), which differed somewhat in form.
Grocheio calls the sections in both the French vocal and instrumental estampie *puncta* (singular *punctus*), Each *puncta* has a pair of lines that repeat the same melody, in the form:
: *aa, bb, cc, etc.*.
The two statements of the melody in each punctus differ only in their endings, described as *apertum* (\"open\") and *clausum* (\"closed\") by Grocheio, who believed that six *puncta* were standard for the stantipes (his term for the estampie), though he was aware of stantipes with seven *puncta*. The structure can therefore be diagrammed as:
: *a+x, a+y; b+w, b+z; etc.*.
In an instrumental estampie, the open and closed endings of the puncta are the same each time, so that the end of the *punctum* serves as the refrain, in the form:
*a+x, a+y; b+x, b+y, c+x, c+y, etc.*
In comparison to other dance forms, Grocheio considered the instrumental estampie \"complicated,\" with *puncta* of varying lengths This is in contrast to the more regular verse length of the ductia. There are also more *puncta* in an estampie than in a ductia. He further states that this difficulty captivates the attention of both the players and listeners because of these complications. According to Grocheio, the vocal estampie begins with a refrain, which is repeated at the end of each stanza, with text and melody independent of the stanza. However, surviving songs do not include a section labeled as a refrain, so some scholars suggest that a convention must have existed for choosing lines to use as a refrain. Like the instrumental form, the vocal dance was complicated enough to require concentration, which helps to distract young people from wicked thoughts.
## History
The estampie is the first known genre of medieval era dance music which continues to exist today.`{{Page needed|date=May 2022}}`{=mediawiki} The earliest reported example of this musical form is the song \"Kalenda maya\", written by the troubadour Raimbaut de Vaqueiras (1180--1207), possibly to a preexisting melody. 14th century examples include *estampies* with subtitles such as \"Isabella\" and \"Tre fontane\".
## Instrumentation
Sources for individual songs do not generally indicate what instruments were used. However, according to Grocheio, the *vielle* was the supreme instrument of the period, and the *stantipes*, together with the cantus coronatus and ductia, were the principal forms played on *vielles* before the wealthy in their celebration. Though the estampie is generally monophonic, there are also two-voice compositions in the form of an estampie, such as the two for keyboard in the Robertsbridge Fragment. The French estampie was performed in a lively triple meter, a primary division of three beats to the bar.
## Dance
## Etymology
According to the *OED*, the name comes from the Provençal *estampida*, feminine of *estampit*, the past participle of *estampir* \"to resound\"
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# Eusebius of Nicomedia
**Eusebius of Nicomedia** (`{{IPAc-en|j|uː|ˈ|s|iː|b|i|ə|s}}`{=mediawiki}; *Εὐσέβιος*; died 341) was an Arian priest who baptised Constantine the Great on his deathbed in 337. A fifth-century legend evolved that Pope Sylvester I was the one to baptise Constantine, but this is dismissed by scholars as a forgery \"to amend the historical memory of the Arian baptism that the emperor received at the end of his life, and instead to attribute an unequivocally orthodox baptism to him\". He was a bishop of Berytus (modern-day Beirut) in Phoenicia. He was later made the bishop of Nicomedia, where the Imperial court resided. He lived finally in Constantinople from 338 up to his death.
## Influence in the Imperial family and the Imperial court {#influence_in_the_imperial_family_and_the_imperial_court}
Distantly related to the imperial family of Constantine the Great, he owed his progression from a less significant Levantine bishopric to the most important episcopal see to his influence at court and the great power he wielded in the church was derived from that source. In fact, during his time in the imperial court, the Eastern court and the major positions in the Eastern Church were held by Arians or Arian sympathizers. With the exception of a short period of eclipse, he enjoyed the confidence both of Constantine and Constantius II. He also served as the tutor of the later Roman emperor Julian, and it was he who might have baptised Constantine the Great on 22 May 337 owing to his familial relationship with the emperor. Also during his time in the imperial court, Arianism became more popular with the royal family. It can be logically surmised that Eusebius had a huge hand in the acceptance of Arianism in the Constantinian household. The Arian influence grew so strong during his tenure in the imperial court that it was not until the end of the Constantinian dynasty and the appointment of Theodosius I that Arianism lost its influence in the empire.
It was of particular interest that Eusebius was nearly persecuted because of his close relationship to the Emperor Licinius while serving as bishop of Nicomedia during Licinius\' reign.
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# Eusebius of Nicomedia
## Relationship with Arius {#relationship_with_arius}
Like Arius, he was a pupil of Lucian of Antioch, and it is probable that he held the same views as Arius from the very beginning; he was also one of Arius\' most fervent supporters and encourager. It was also because of this relationship that he was the first person whom Arius contacted after the latter was excommunicated from Alexandria by Alexander I of Alexandria in 321. Apparently, Arius and Eusebius were close enough and Eusebius powerful enough that Arius was able to put his theology down in writing. He afterward modified his ideas somewhat, or perhaps he only yielded to the pressure of circumstances; but he was, if not the teacher, at all events the leader and organizer of the Arian council.
At the First Council of Nicaea in 325, he signed the Confession, but only after a long and desperate opposition in which he was said to \"subscribe with hand only, not heart\" according to ancient sources. It was a huge blow to the Arian party since it was surmised that the participants in the First Council of Nicaea were evenly split between non-Arians and Arians. His defense of Arius angered the emperor, and a few months after the council he was sent into exile due to his continual contacts with Arius and his followers. After the lapse of three years, he succeeded in regaining the imperial favor by convincing Constantine that Arius and his views do not conflict with the proclaimed Nicene Creed. After his return in 329, he brought the whole machinery of the state government into action in order to impose his views upon the Church.
## Political and religious career {#political_and_religious_career}
In complement to his theological interests, Eusebius was a skilled politician. Upon his return, he regained the lost ground resulting from the First Council of Nicaea, established alliances with other groups such as the Melitians and expelled many opponents.
He was described by modern historians as an \"ambitious intriguer\" and a \"consummate political player\". He was also described by ancient sources as a high-handed person who was also aggressive in his dealings; he also used his allies to spy on his opponents.
He was able to dislodge and exile three key opponents who espoused the First Council of Nicaea: Eustathius of Antioch in 330, Athanasius of Alexandria in 335 and Marcellus of Ancyra in 336. This was no small feat since Athanasius was regarded as a \"man of God\" by Constantine, and both Eustathius and Athanasius held top positions in the church.
Another major feat was his appointment as the Patriarch of Constantinople by expelling Paul I of Constantinople; Paul I would eventually return as Patriarch after Eusebius\'s death.
Even outside the empire, Eusebius had great influence. He brought Ulfilas into the Arian priesthood and sent the latter to convert the heathen Goths.
Eusebius baptised Constantine the Great in his villa in Nicomedia, on 22 May 337 just before the death of the Emperor.
## Death and aftermath {#death_and_aftermath}
He died at the height of his power in the year 341.
He was so influential that even after his death, Constantius II heeded his and Eudoxus of Constantinople\'s advice to attempt to convert the Roman Empire to Arianism by creating Arian Councils and official Arian Doctrines.
It was because of Eusebius that \"On the whole, Constantine and his successors made life pretty miserable for Church leaders committed to the Nicene decision and its Trinitarian formula\".
Eusebius of Nicomedia is not to be confused with his contemporary Eusebius of Caesarea, the author of well-known early books of Church history
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# Exothermic process
In thermodynamics, an **exothermic process** (`{{etymology|grc|''{{Wikt-lang|grc|έξω}}'' ({{grc-transl|έξω}})|outward||''{{Wikt-lang|grc|θερμικός}}'' ({{grc-transl|θερμικός}})|thermal}}`{=mediawiki}) is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e.g. a battery), or sound (e.g. explosion heard when burning hydrogen). The term *exothermic* was first coined by 19th-century French chemist Marcellin Berthelot.
The opposite of an exothermic process is an endothermic process, one that absorbs energy, usually in the form of heat. The concept is frequently applied in the physical sciences to chemical reactions where chemical bond energy is converted to thermal energy (heat).
## Two types of chemical reactions {#two_types_of_chemical_reactions}
Exothermic and endothermic describe two types of chemical reactions or systems found in nature, as follows:
### Exothermic
An exothermic reaction occurs when heat is released to the surroundings. According to the IUPAC, an exothermic reaction is \"a reaction for which the overall standard enthalpy change Δ*H*⚬ is negative\". Some examples of exothermic process are fuel combustion, condensation and nuclear fission, which is used in nuclear power plants to release large amounts of energy.
### Endothermic
In an endothermic reaction or system, energy is taken from the surroundings in the course of the reaction, usually driven by a favorable entropy increase in the system. An example of an endothermic reaction is a first aid cold pack, in which the reaction of two chemicals, or dissolving of one in another, requires calories from the surroundings, and the reaction cools the pouch and surroundings by absorbing heat from them.
Photosynthesis, the process that allows plants to convert carbon dioxide and water to sugar and oxygen, is an endothermic process: plants absorb radiant energy from the sun and use it in an endothermic, otherwise non-spontaneous process. The chemical energy stored can be freed by the inverse (spontaneous) process: combustion of sugar, which gives carbon dioxide, water and heat (radiant energy).
## Energy release {#energy_release}
Exothermic refers to a transformation in which a closed system releases energy (heat) to the surroundings, expressed by
$$Q > 0.$$
When the transformation occurs at constant pressure and without exchange of electrical energy, heat `{{mvar|Q}}`{=mediawiki} is equal to the enthalpy change, i.e.
$$\Delta H < 0,$$
While at constant volume, according to the first law of thermodynamics it equals internal energy (`{{mvar|U}}`{=mediawiki}) change, i.e.
$$\Delta U = Q + 0 > 0.$$
In an adiabatic system (i.e. a system that does not exchange heat with the surroundings), an otherwise exothermic process results in an increase in temperature of the system.
In exothermic chemical reactions, the heat that is released by the reaction takes the form of electromagnetic energy or kinetic energy of molecules. The transition of electrons from one quantum energy level to another causes light to be released. This light is equivalent in energy to some of the stabilization energy of the energy for the chemical reaction, i.e. the bond energy. This light that is released can be absorbed by other molecules in solution to give rise to molecular translations and rotations, which gives rise to the classical understanding of heat. In an exothermic reaction, the activation energy (energy needed to start the reaction) is less than the energy that is subsequently released, so there is a net release of energy.
## Examples
Some examples of exothermic processes are:
- Combustion of fuels such as wood, coal and oil/petroleum
- The thermite reaction
- The reaction of alkali metals and other highly electropositive metals with water
- Condensation of rain from water vapor
- Mixing water and strong acids or strong bases
- The reaction of acids and bases
- Dehydration of carbohydrates by sulfuric acid
- The setting of cement and concrete
- Some polymerization reactions such as the setting of epoxy resin
- The reaction of most metals with halogens or oxygen
- Nuclear fusion in hydrogen bombs and in stellar cores (to iron)
- Nuclear fission of heavy elements
- The reaction between zinc and hydrochloric acid
- Respiration (breaking down of glucose to release energy in cells)
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# Exothermic process
## Implications for chemical reactions {#implications_for_chemical_reactions}
Chemical exothermic reactions are generally more spontaneous than their counterparts, endothermic reactions.
In a thermochemical reaction that is exothermic, the heat may be listed among the products of the reaction
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# Émile Baudot
**Jean-Maurice-Émile Baudot** (`{{IPA|fr|eˈmil boˈdo|lang}}`{=mediawiki}; 11 September 1845 -- 28 March 1903), French telegraph engineer and inventor of the first means of digital communication Baudot code, was one of the pioneers of telecommunications. He invented a multiplexed printing telegraph system that used his code and allowed multiple transmissions over a single line. The baud unit was named after him.
## Early life {#early_life}
Baudot was born in Magneux, Haute-Marne, France, the son of farmer Pierre Émile Baudot, who later became the mayor of Magneux. His only formal education was at his local primary school, after which he carried out agricultural work on his father\'s farm before joining the French Post & Telegraph Administration as an apprentice operator in 1869.
The telegraph service trained him in the Morse telegraph and also sent him on a four-month course of instruction on the Hughes printing telegraph system, which was later to inspire his own system.
After serving briefly during the Franco-Prussian War, he returned to civilian duties in Paris in 1872.
## Telegraphy
The Telegraph Service encouraged Baudot to develop---on his own time---a system for time-multiplexing several telegraph messages using Hughes teleprinters. He realised that with most printing telegraphs of the period the line is idle for most of the time, apart from the brief intervals when a character is transmitted. Baudot devised one of the first applications of time-division multiplexing in telegraphy. Using synchronized clockwork-powered switches at the transmitting and receiving ends, he was able to transmit five messages simultaneously; the system was officially adopted by the French Post & Telegraph Administration five years later.
Baudot invented his telegraph code in 1870 and patented it in 1874. It was a 5-bit code, with equal on and off intervals, which allowed telegraph transmission of the Roman alphabet, punctuation and control signals. By 1874 or 1875 (various sources give both dates) he had also perfected the electromechanical hardware to transmit his code. His inventions were based on the printing mechanism from Hughes\' instrument, a distributor invented by Bernard Meyer in 1871, and the five-unit code devised by Carl Friedrich Gauss and Wilhelm Weber. Baudot combined these, together with original ideas of his own, to produce a complete multiplex system.
## Baudot system {#baudot_system}
On 17 June 1874 Baudot patented his first printing telegraph (Patent no. 103,898 \"Système de télégraphie rapide\"), in which the signals were translated automatically into typographic characters. Baudot\'s hardware had three main parts: the keyboard, the distributor, and a paper tape.
Each operator - there were as many as four - was allocated a single sector. The keyboard had just five piano type keys, operated with two fingers of the left hand and three fingers of the right hand. The five unit code was designed to be easy to remember. Once the keys had been pressed they were locked down until the contacts again passed over the sector connected to that particular keyboard, when the keyboard was unlocked ready for the next character to be entered, with an audible click (known as the \"cadence signal\") to warn the operator. Operators had to maintain a steady rhythm, and the usual speed of operation was 30 words per minute.
The receiver was also connected to the distributor. The signals from the telegraph line were temporarily stored on a set of five electromagnets, before being decoded to print the corresponding character on paper tape.
Accurate operation of this system depended on the distributor at the transmitting end keeping in synchronization with the one at the receiving end and operators only sending characters when the contacts passed over their allocated sector. This could be achieved at a speed of 30 wpm by strictly observing the \"cadence\" of rhythm of the system when the distributor gave the operator the use of the line.
## First use {#first_use}
The Baudot system was accepted by the French Telegraph Administration in 1875, with the first online tests of his system occurring between Paris and Bordeaux on 12 November 1877. At the end of 1877, the Paris-Rome line, which was about 1700 km, began operating a duplex Baudot.
The Baudot apparatus was shown at the Paris Exposition Universelle (1878) and won him the Exposition\'s gold medal, as well as bringing his system to worldwide notice.
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# Émile Baudot
## Later career {#later_career}
After the first success of his system, Baudot was promoted to Controller in 1880, and was named Inspector-Engineer in 1882.
In July 1887 he conducted successful tests on the Atlantic telegraph cable between Weston-super-Mare and Waterville, Nova Scotia operated by the Commercial Company, with a double Baudot installed in duplex, the Baudot transmitters and receivers substituted for the recorder.
On 8 August 1890 he established communications between Paris, Vannes, and Lorient over a single wire. On 3 January 1894 he installed a triplex apparatus on the telegraph between Paris and Bordeaux that had previously been operating with some difficulty on the Hughes telegraph system. On 27 April 1894 he established communications between the Paris stock exchange and the Milan stock exchange, again over a single wire, using his new invention, the retransmitter.
In 1897 the Baudot system was improved by switching to punched tape, which was prepared offline like the Morse tape used with the Wheatstone and Creed systems. A tape reader, controlled by the Baudot distributor, then replaced the manual keyboard. The tape had five rows of holes for the code, with a sixth row of smaller holes for transporting the tape through the reader mechanism. Baudot\'s code was later standardised as International Telegraph Alphabet Number One.
Baudot received little help from the French Telegraph Administration for his system, and often had to fund his own research, even having to sell the gold medal awarded by the 1878 Exposition Universelle in 1880.
The Baudot telegraph system was employed progressively in France, and then was adopted in other countries, Italy being the first to introduce it, in its inland service, in 1887. The Netherlands followed in 1895, Switzerland in 1896, and Austria and Brazil in 1897. The British Post Office adopted it for a simplex circuit between London and Paris during 1897, then used it for more general purposes from 1898. In 1900 it was adopted by Germany, by Russia in 1904, the British West Indies in 1905, Spain in 1906, Belgium in 1909, Argentina in 1912, and Romania in 1913.
## Final years {#final_years}
Baudot married Marie Josephine Adelaide Langrognet on 15 January 1890. She died only three months later, on 9 April 1890.
Soon after starting work with the telegraph service, Baudot began to suffer physical discomfort and was frequently absent from work for this reason, for as long as a month on one occasion. His condition affected him for the rest of his life, until he died on 28 March 1903, at Sceaux, Hauts-de-Seine, near Paris, at the age of 57.
## Mimault patent suit {#mimault_patent_suit}
In 1874, French telegraph operator Louis Victor Mimault patented a telegraph system using five separate lines to transmit. After his patent was rejected by the Telegraph Administration, Mimault modified his device to incorporate features from the Meyer telegraph and obtained a new patent which was also rejected. In the meantime, Baudot had patented his prototype telegraph a few weeks earlier.
Mimault claimed priority of invention over Baudot and brought a patent suit against him in 1877. The Tribunal Civil de la Seine, which reviewed testimony from three experts unconnected with the Telegraph Administration, found in favor of Mimault and accorded him priority of invention of the Baudot code and ruled that Baudot\'s patents were simply improvements of Mimault\'s. Neither inventor was satisfied with this judgment, which was eventually rescinded with Mimault being ordered to pay all legal costs.
Mimault became unnerved because of the decision, and after an incident where he shot at and wounded two students of the École Polytechnique (charges for which were dropped), he demanded a special act to prolong the duration of his patents, 100,000 Francs, and election to the Légion d\'honneur. A commission directed by Jules Raynaud (head of telegraph research) rejected his demands. Upon hearing the decision, Mimault shot and killed Raynaud, and was sentenced to 10 years of forced labour and 20 years of exile.
## Honors
- 1881 - Diploma of Honor from the International Electrical Exposition.
- 1882 - Gold medal from the Société d\'Encouragement pour l\'Industrie Nationale (SEIN)
- 1889 - Ampere Medal from SEIN
- 1878 - Knight\'s Cross of the Légion d\'honneur
- 1882 - Knight of the Order of Leopold
- 1884 - Knight of the Order of Franz Joseph of Austria.
- 1891 - Cross of the Order of the Crown of Italy
- 1898 - Promoted to Officier of the Légion d\'honneur
- 1900 - Knight of the Order of Saints Maurice and Lazarus (Italy)
- 1901 - Knight of the Order of the Crown of Italy
- A street in the 17th arrondissement of Paris was named after Baudot, but it no longer exists.
- In 1926 the International Telegraph Communications Advisory Committee of the International Telecommunication Union met in Berlin and immortalized Baudot by designating the baud - shortened from his name - as the unit of telegraph transmission speed.
- In 1949, the French Post Office issued a series of stamps with his portrait. By mistake, the year of his birth was given as 1848, not the correct 1845. The stamp was corrected and reprinted with a different color. However, the erroneous stamps still circulate among philatelists and have greater value than the corrected stamps
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# Economic security
**Economic security** or financial security is the condition of having stable income or other resources to support a standard of living now and in the foreseeable future. It includes:
- probable continued solvency
- predictability of the future cash flow of a person or other economic entity, such as a country
- employment security or job security
Without such security, people may experience its opposite: economic insecurity and resulting economic anxiety.
Financial security more often refers to individual and family money management and savings. Economic security tends to include the broader effect of a society\'s production levels and monetary support for non-working citizens.
## Components of individual economic security {#components_of_individual_economic_security}
In the United States, children\'s economic security is indicated by the income level and employment security of their families or organizations. Economic security of people over 50 years old is based on Social Security benefits, pensions and savings, earnings and employment, and health insurance coverage.
### Arizona
In 1972, the state legislature of Arizona formed a Department of Economic Security with a mission to promote \"the safety, well-being, and self sufficiency of children, adults, and families\". This department combines state government activities previously managed by the Employment Security Commission, the State Department of Public Welfare, the Division of Vocational Rehabilitation, the State Office of Economic Opportunity, the Apprenticeship Council, and the State Office of Manpower Planning. The State Department of Mental Retardation (renamed the Division of Developmental Disabilities, House Bill 2213) joined the Department in 1974 . The purpose in creating the Department was to provide an integration of direct services to people in such a way as to reduce duplication of administrative efforts, services and expenditures. Family Connections became a part of the Department in January 2007.
### Minnesota
The Minnesota Department of Economic Security was formed in 1977 from the departments of Employment Services and Vocational Rehabilitation, the Governor\'s Manpower Office, and the Economic Opportunity Office, which administered anti-poverty programs. In 1985, State Services for the Blind was included in this department. In 2003, the Minnesota Department of Economic Security and Minnesota Department of Trade and Economic Development were merged to form The Minnesota Department of Employment and Economic Development.
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# Economic security
## National economic security {#national_economic_security}
In the context of domestic politics and international relations, **national economic security** is the ability of a country to follow its choice of policies to develop the national economy in the manner desired. Historically, conquest of nations have made conquerors rich through plunder, access to new resources and enlarged trade through controlling of the economies of conquered nations. Today\'s complex system of international trade is characterized by multi-national agreements and mutual inter-dependence. Availability of natural resources and capacity for production and distribution are essential under this system, leading many experts to consider economic security to be as important a part of national security as military policy.
Economic security has been proposed as a key determinant of international relations, particularly in the geopolitics of petroleum in American foreign policy after 1973 oil crisis and September 11, 2001.
In Canada, threats to the country\'s overall economic security are considered **economic espionage**, which is \"illegal, clandestine or coercive activity by a foreign government in order to gain unauthorized access to economic intelligence, such as proprietary information or technology, for economic advantage.\"
In January 2021, the United States Department of Homeland Security (DHS) issued Strategic Action Plan to Counter the Threat Posed by China.
In October 2021 in Japan, prime minister Fumio Kishida created the first-ever ministerial post for economic security. And in April 2022, Japan\'s National Diet passed an economic security bill aimed at guarding technology and reinforcing critical supply chains, while also imposing tighter oversight of Japanese firms working in sensitive sectors or critical infrastructure. Measures in the legislation, which is primarily aimed at warding off risks from China, will be implemented over two years once it is enacted, according to the bill.
In March 2023, Japan and Germany agreed to strengthen cooperation on economic security in the aftermath of tensions over global supply chains and the economic impact of Russian invasion of Ukraine. In the first high-ministerial government consultations held between the two countries, German Chancellor Olaf Scholz reached out to Tokyo to seek to reduce Germany\'s dependence on China for imports of raw materials.
On April 4, 2023, a G7 Trade Ministers\' Meeting via video conference was held to discuss on enhancing economic security, and a G7 Trade Ministers\' Statement was issued on the day. Also in April 2023, Japan\'s Public Security Intelligence Agency (PSIA) launched a division dedicated to economic security. The agency also plans to set up such dedicated units in its regional bureaus nationwide to step up efforts to prevent cutting-edge technology and data from being leaked out of the country. On 20 May 2023 on occasion of the G7 Hiroshima summit, economic security was discussed for the first time as the G7 agenda, and \"G7 Leaders\' Statement on Economic Resilience and Economic Security\" was issued based on the discussion.
On 20 June 2023, the European Commission and the High Representative proposed a Joint Communication on a European Economic Security Strategy which will be discussed by EU leaders at their meeting.
## Other
It is widely believed that there is a tradeoff between economic security and economic opportunity
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# Eth, Nord
**Eth** (`{{IPA|fr|ɛt}}`{=mediawiki}) is a commune in the Nord department in northern France.
It is about 10 km east-southeast of Valenciennes. Residents are called Ethois (feminine plural Ethoises)
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# Euphrates
The **Euphrates** (`{{IPAc-en|audio=En-us-Euphrates.ogg|juː|ˈ|f|r|eɪ|t|iː|z}}`{=mediawiki} `{{respell|yoo|FRAY|teez}}`{=mediawiki}; see below) is the longest and one of the most historically important rivers of West Asia. Together with the Tigris, it is one of the two defining rivers of Mesopotamia (`{{literal translation|the land between the rivers}}`{=mediawiki}). Originating in Turkey, the Euphrates flows through Syria and Iraq to join the Tigris in the Shatt al-Arab in Iraq, which empties into the Persian Gulf.
The Euphrates is the fifteenth-longest river in Asia and the longest in West Asia, at about 2780 km, with a drainage area of 440000 km2 that covers six countries.
## Etymology
The term *Euphrates* derives from the Greek *Euphrátēs* (*Εὐφρᾱ́της\]\]*), adapted from *translit=\<sup\>h\</sup\>Ufrātuš*, itself from *translit=Úipratuiš*. The Elamite name is ultimately derived from cuneiform 𒌓𒄒𒉣; read as *Buranun* in Sumerian and *Purattu* in Akkadian; many cuneiform signs have a Sumerian pronunciation and an Akkadian pronunciation, taken from a Sumerian word and an Akkadian word that mean the same. The Akkadian *Purattu* has been perpetuated in Semitic languages (cf. *الفرات* *al-Furāt*; *̇ܦܪܬ* *Pǝrāṯ*, *פְּרָת* *Pǝrāṯ*) and in other nearby languages of the time (cf. Hurrian *Puranti*, Sabarian *Uruttu*). The Elamite, Akkadian, and possibly Sumerian forms are suggested to be from an unrecorded substrate language. Tamaz V. Gamkrelidze and Vyacheslav Ivanov suggest the proto-Sumerian *\*burudu* \"copper\" (Sumerian *urudu*) as an origin, with an explanation that Euphrates was the river by which copper ore was transported in rafts, since Mesopotamia was the center of copper metallurgy during the period.
The Euphrates is called *Yeprat* in Armenian (*Եփրատ*), *Perat* in modern Hebrew (*פרת*), *Fırat* in Turkish and *Firat* in Kurdish. The Mandaic name is `{{transliteration|myz|Praš}}`{=mediawiki} (*ࡐࡓࡀࡔ*), and is often mentioned as `{{transliteration|myz|Praš [[Ziwa (Aramaic)|Ziwa]]}}`{=mediawiki} (pronounced `{{transliteration|myz|Fraš Ziwa}}`{=mediawiki}) in Mandaean scriptures such as the *Ginza Rabba*. In Mandaean scriptures, the Euphrates is considered to be the earthly manifestation of the heavenly yardna or flowing river (similar to the Yazidi concept of Lalish being the earthly manifestation of its heavenly counterpart, or the 'Sacred House' Kaaba in Mecca being the earthly manifestation of the heavenly Al-Bayt Al-Mamur).
The earliest references to the Euphrates come from cuneiform texts found in Shuruppak and pre-Sargonic Nippur in southern Iraq and date to the mid-3rd millennium BCE. In these texts, written in Sumerian, the Euphrates is called *Buranuna* (logographic: UD.KIB.NUN). The name could also be written KIB.NUN.(NA) or ^d^KIB.NUN, with the prefix \"^d^\" indicating that the river was a divinity. In Sumerian, the name of the city of Sippar in modern-day Iraq was also written UD.KIB.NUN, indicating a historically strong relationship between the city and the river.
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