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Vapor-compression refrigeration
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Description
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Unfortunately, chlorine- and fluorine-bearing refrigerants reach the upper atmosphere when they escape. In the stratosphere, substances like CFCs and HCFCs break up due to UV radiation, releasing their chlorine free-radicals. These chlorine free-radicals act as catalysts in the breakdown of ozone through chain reactions. One CFC molecule can cause thousands of ozone molecules to break down. This causes severe damage to the ozone layer that shields the Earth's surface from the Sun's strong UV radiation and has been shown to lead to increased rates of skin cancer. The chlorine will remain active as a catalyst until and unless it binds with another particle, forming a stable molecule. CFC refrigerants in common but receding usage include R-11 and R-12.
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Vapor-compression refrigeration
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Description
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Newer refrigerants that have reduced ozone depletion effects compared to CFCs have replaced most CFC use. Examples include HCFCs (such as R-22, used in most homes) and HFCs (such as R-134a, used in most cars). HCFCs in turn are being phased out under the Montreal Protocol and replaced by hydrofluorocarbons (HFCs), which do not contain chlorine atoms. However, CFCs, HCFCs, and HFCs all have very large global warming potential (GWP).
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Vapor-compression refrigeration
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Description
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More benign refrigerants are currently the subject of research, such as supercritical carbon dioxide, known as R-744. These have similar efficiencies compared to existing CFC- and HFC-based compounds, and have many orders of magnitude lower global warming potential. General industry and governing body push are toward more GWP-friendly refrigerants. In industrial settings ammonia, as well gasses like ethylene, propane, iso-butane and other hydrocarbons are commonly used (and have own R-x customary numbers), depending on required temperatures and pressures. Many of these gases are unfortunately flammable, explosive, or toxic; making their use restricted (i.e. well-controlled environment by qualified personnel, or a very small amount of refrigerant used). HFOs which can be considered to be HFC with some carbon-carbon bonds being double bounds, do show promise of lowering GWP very low to be of no further concern. In the meantime, various blends of existing refrigerants are used to achieve the required properties and efficiency, at a reasonable cost and lower GWP.
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Vapor-compression refrigeration
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Thermodynamic analysis of the system
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The thermodynamics of the vapor compression cycle can be analyzed on a temperature versus entropy diagram as depicted in Figure 2. At point 1 in the diagram, the circulating refrigerant enters the compressor as a low-temperature, low-pressure saturated vapor. From point 1 to point 2, the vapor is isentropically compressed (compressed at constant entropy) and exits the compressor as a high-pressure, high-temperature superheated vapor. Superheat is the amount of sensible heat added to the vapor above its saturation point, i.e. its boiling point.
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Vapor-compression refrigeration
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Thermodynamic analysis of the system
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From point 2 to point 3, the vapor travels through part of the condenser which removes the superheat by cooling the vapor. Between point 3 and point 4, the vapor travels through the remainder of the condenser and is condensed into a high-temperature, high-pressure subcooled liquid. Subcool is the amount of sensible heat removed from the liquid below its maximum saturation. The condensation process occurs at essentially constant pressure.
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Vapor-compression refrigeration
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Thermodynamic analysis of the system
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Between points 4 and 5, the subcooled liquid refrigerant passes through the expansion valve and undergoes an abrupt decrease of pressure. That process results in the adiabatic flash evaporation and auto-refrigeration of a portion of the liquid (typically, less than half of the liquid flashes). The adiabatic flash evaporation process is isenthalpic (occurs at constant enthalpy).
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Vapor-compression refrigeration
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Thermodynamic analysis of the system
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Between points 5 and 1, the cold and partially vaporized refrigerant travels through the coil or tubes in the evaporator where it is totally vaporized by the warm air (from the space being refrigerated) that a fan circulates across the coil or tubes in the evaporator. The evaporator operates at essentially constant pressure and boils off all available liquid after adding 4–8 kelvins of superheat to the refrigerant in order to make sure the liquid has evaporated completely. This is a safeguard for the compressor, as it cannot pump liquid.
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Vapor-compression refrigeration
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Thermodynamic analysis of the system
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The resulting superheated vapor returns to the compressor inlet at point 1 to complete the thermodynamic cycle.
The above discussion is based on the ideal vapor-compression refrigeration cycle which does not take into account real world items like frictional pressure drop in the system, slight internal irreversibility during the compression of the refrigerant vapor, or non-ideal gas behavior (if any).
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Vapor-compression refrigeration
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Types of gas compressors
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The most common compressors used in refrigeration are reciprocating and scroll compressors, but large chillers or industrial cycles may use rotary screw or centrifugal compressors. Each application prefers one or another due to size, noise, efficiency, and pressure issues. Compressors are often described as being either open, hermetic, or semi-hermetic, to describe how the compressor and/or motor is situated in relation to the refrigerant being compressed. Variations of motor/compressor types can lead to the following configurations: Hermetic motor, hermetic compressor Hermetic motor, semi-hermetic compressor Open motor (belt driven or close coupled), hermetic compressor Open motor (belt driven or close coupled), semi-hermetic compressorTypically in hermetic, and most semi-hermetic compressors (sometimes known as accessible hermetic compressors), the compressor and motor driving the compressor are integrated, and operate within the refrigerant system. The motor is hermetic and is designed to operate, and be cooled by, the refrigerant being compressed. The obvious disadvantage of hermetic motor compressors is that the motor drive cannot be maintained in situ, and the entire compressor must be removed if a motor fails. A further disadvantage is that burnt out windings can contaminate whole refrigeration systems requiring the system to be entirely pumped down, and the refrigerant replaced.
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Vapor-compression refrigeration
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Types of gas compressors
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An open compressor has a motor drive which is outside of the refrigeration system, and provides drive to the compressor by means of an input shaft with suitable gland seals. Open compressor motors are typically air-cooled and can be fairly easily exchanged or repaired without degassing of the refrigeration system. The disadvantage of this type of compressor is a failure of the shaft seals, leading to loss of refrigerant.
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Vapor-compression refrigeration
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Types of gas compressors
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Open motor compressors are generally easier to cool (using ambient air) and therefore tend to be simpler in design and more reliable, especially in high pressure applications where compressed gas temperatures can be very high. However the use of liquid injection for additional cooling can generally overcome this issue in most hermetic motor compressors.
Reciprocating compressors Reciprocating compressors are piston-style, positive displacement compressors.
Rotary screw compressors Rotary screw compressors are also positive displacement compressors. Two meshing screw-rotors rotate in opposite directions, trapping refrigerant vapor, and reducing the volume of the refrigerant along the rotors to the discharge point.
Small units are not practical due to back-leakage but large units have very high efficiency and flow capacity.
Centrifugal compressors Centrifugal compressors are dynamic compressors. These compressors raise the pressure of the refrigerant by imparting velocity or dynamic energy, using a rotating impeller, and converting it to pressure energy.
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Vapor-compression refrigeration
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Types of gas compressors
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Centrifugal Compressor Surge Chillers with centrifugal compressors have a 'Centrifugal Compressor Map' that shows the "surge line" and the "choke line." For the same capacity ratings, across a wider span of operating conditions, chillers with the larger diameter lower-speed compressor have a wider 'Centrifugal Compressor Map' and experience surge conditions less than those with the smaller diameter, less expensive, higher-speed compressors. The smaller diameter, higher-speed compressors have a flatter curve.,As the refrigerant flow rate decreases, some compressors change the gap between the impeller and the volute to maintain the correct velocity to avoid surge conditions.
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Vapor-compression refrigeration
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Types of gas compressors
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Scroll compressors Scroll compressors are also positive displacement compressors. The refrigerant is compressed when one spiral orbits around a second stationary spiral, creating smaller and smaller pockets and higher pressures. By the time the refrigerant is discharged, it is fully pressurized.
Others
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Vapor-compression refrigeration
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Compressor lubrication
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In order to lubricate the moving parts of the compressor, oil is added to the refrigerant during installation or commissioning. The type of oil may be mineral or synthetic to suit the compressor type, and also chosen so as not to react with the refrigerant type and other components in the system. In small refrigeration systems the oil is allowed to circulate throughout the whole circuit, but care must be taken to design the pipework and components such that oil can drain back under gravity to the compressor. In larger more distributed systems, especially in retail refrigeration, the oil is normally captured at an oil separator immediately after the compressor, and is in turn re-delivered, by an oil level management system, back to the compressor(s). Oil separators are not 100% efficient so system pipework must still be designed so that oil can drain back by gravity to the oil separator or compressor.
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Vapor-compression refrigeration
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Compressor lubrication
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Some newer compressor technologies use magnetic bearings or air bearings and require no lubrication, for example the Danfoss Turbocor range of centrifugal compressors. Avoiding the need for oil lubrication and the design requirements and ancillaries associated with it, simplifies the design of the refrigerant system, increases the heat transfer coefficient in evaporators and condensers, eliminates the risk of refrigerant being contaminated with oil, and reduces maintenance requirements.
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Vapor-compression refrigeration
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Control
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In simple commercial refrigeration systems the compressor is normally controlled by a simple pressure switch, with the expansion performed by a capillary tube or thermal expansion valve. In more complex systems, including multiple compressor installations, the use of electronic controls is typical, with adjustable set points to control the pressure at which compressors cut in and cut out, and temperature control by the use of electronic expansion valves.
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Vapor-compression refrigeration
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Control
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In addition to the operational controls, separate high-pressure and low-pressure switches are normally utilised to provide secondary protection to the compressors and other components of the system from operating outside of safe parameters.
In more advanced electronic control systems the use of floating head pressure, and proactive suction pressure, control routines allow the compressor operation to be adjusted to accurately meet differing cooling demands while reducing energy consumption.
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Vapor-compression refrigeration
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Other features and facts of interest
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The schematic diagram of a single-stage refrigeration system shown in Figure 1 does not include other equipment items that would be provided in a large commercial or industrial vapor compression refrigeration system, such as: A horizontal or vertical pressure vessel, equipped internally with a demister, between the evaporator and the compressor inlet to capture and remove any residual, entrained liquid in the refrigerant vapor because liquid may damage the compressor. Such vapor-liquid separators are most often referred to as "suction line accumulators". (In other industrial processes, they are called "compressor suction drums" or "knockout pots".) Large commercial or industrial refrigeration systems may have multiple expansion valves and multiple evaporators in order to refrigerate multiple enclosed spaces or rooms. In such systems, the condensed liquid refrigerant may be routed into a pressure vessel, called a receiver, from which liquid refrigerant is withdrawn and routed through multiple pipelines to the multiple expansion valves and evaporators.
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Vapor-compression refrigeration
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Other features and facts of interest
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Filter Dryers, installed before the compressors to catch any moisture or contaminants in the system and thus protect the compressors from internal damage Some refrigeration units may have multiple stages which requires the use of multiple compressors in various arrangements.In most of the world, the cooling capacity of refrigeration systems is measured in watts. Common residential air conditioning units range in capacity from 3.5 to 18 kilowatt. In a few countries it is measured in "tons of refrigeration", with common residential air conditioning units from about 1 to 5 tons of refrigeration.
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Vapor-compression refrigeration
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Economic analysis
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Advantages Very mature technology.
Relatively inexpensive.
Can be driven directly using mechanical energy (water, car or truck motor) or with electrical energy.
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Vapor-compression refrigeration
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Economic analysis
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Efficient up to 60% of Carnot's theoretical limit (as evaluated in ASHRAE testing conditions: evaporation temperature of −23.3 °C, condensing temperature of 54.4 °C, and ambient temperature of 32 °C) based on some of the best commercially available compressors, as produced by manufacturers Danfoss, Matsushita, Copeland, Embraco, Bristol, and Tecumseh. However, many refrigeration systems use compressors that have lower efficiencies of between 40 and 55%, since the 60% efficient ones cost almost twice as much as the lower efficiency ones.
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Vapor-compression refrigeration
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Economic analysis
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Disadvantages Many systems still use HCFC refrigerants, which contribute to depletion of the Earth's ozone layer. In countries adhering to the Montreal Protocol, HCFCs are due to be phased out and are largely being replaced by ozone-friendly HFCs. However, systems using HFC refrigerants tend to be slightly less efficient than systems using HCFCs. HFCs also have an extremely large global warming potential, because they remain in the atmosphere for many years and trap heat more effectively than carbon dioxide.
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Vapor-compression refrigeration
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Economic analysis
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With the ultimate phasing out of HCFCs already a certainty, alternative non-haloalkane refrigerants are gaining popularity. In particular, once-abandoned refrigerants such as hydrocarbons (butane for example) and CO2 are coming back into more extensive use. For example, Coca-Cola's vending machines at the 2006 FIFA World Cup in Germany used refrigeration utilizing CO2. Ammonia (NH3) is one of the oldest refrigerants, with excellent performance and essentially no pollution problems. However, ammonia has two disadvantages: it is toxic and it is incompatible with copper tubing.
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Vapor-compression refrigeration
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History
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In 1805, the American inventor Oliver Evans described a closed vapor-compression refrigeration cycle for the production of ice by ether under vacuum. Heat would be removed from the environment by recycling vaporized refrigerant, where it would move through a compressor and condenser, and would eventually revert to a liquid form in order to repeat the refrigeration process over again. However, no such refrigeration unit was built by Evans.In 1834, an American expatriate to Great Britain, Jacob Perkins, built the first working vapor-compression refrigeration system in the world. It was a closed-cycle that could operate continuously, as he described in his patent: I am enabled to use volatile fluids for the purpose of producing the cooling or freezing of fluids, and yet at the same time constantly condensing such volatile fluids, and bringing them again into operation without waste.His prototype system worked although it did not succeed commercially.A similar attempt was made in 1842, by American physician, John Gorrie, who built a working prototype, but it was a commercial failure. American engineer Alexander Twining took out a British patent in 1850 for a vapor compression system that used ether.
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Vapor-compression refrigeration
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History
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The first practical vapor compression refrigeration system was built by James Harrison, a British journalist who had emigrated to Australia. His 1856 patent was for a vapor compression system using ether, alcohol or ammonia. He built a mechanical ice-making machine in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Victoria, and his first commercial ice-making machine followed in 1854. Harrison also introduced commercial vapor-compression refrigeration to breweries and meat packing houses and, by 1861, a dozen of his systems were in operation in Australia and England.
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Vapor-compression refrigeration
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History
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The first gas absorption refrigeration system using gaseous ammonia dissolved in water (referred to as "aqua ammonia") was developed by Ferdinand Carré of France in 1859 and patented in 1860. Carl von Linde, an engineering professor at the Technological University Munich in Germany, patented an improved method of liquefying gases in 1876. His new process made possible using gases such as ammonia, sulfur dioxide SO2, and methyl chloride (CH3Cl) as refrigerants and they were widely used for that purpose until the late 1920s.
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Rockslide
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Rockslide
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A rockslide is a type of landslide caused by rock failure in which part of the bedding plane of failure passes through compacted rock and material collapses en masse and not in individual blocks. Note that a rockslide is similar to an avalanche because they are both slides of debris that can bury a piece of land. While a landslide occurs when loose dirt or sediment falls down a slope, a rockslide occurs only when solid rocks are transported down slope. The rocks tumble downhill, loosening other rocks on their way and smashing everything in their path. Fast-flowing rock slides or debris slides behave similarly to snow avalanches, and are often referred to as rock avalanches or debris avalanches.
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Rockslide
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Definition
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The term landslide refers to a variety of mass wasting events (geologic slope failures) that include slumps, slides, falls, and flows. The two major types of slides are rotational slides and translational slides. Rockslides are a type of translational event since the rock mass moves along a roughly planar surface with little rotation or backward tilting. Rock slides are the most dangerous form of mass-wasting because they incorporate a sudden, incredibly fast-paced release of bedrock along a uniform plane of weakness. These uniform weaknesses are key to identifying rock slides because unlike slumps, flows, or falls, the failed material moves in a fairly uniform direction over a layer of solid, pre-existing rock. Rock may break down while falling during rockslides. The sudden, rapid release of material found in rock slides combined with the sheer size and weight of the material that is falling is what gives these events the potential to have devastating effects on human life and infrastructure. Rock slides are very common in the over steepened canyons and drainages of Idaho, particularly in those areas like the Salmon River Canyon where more than 5,000 feet of elevation may exist between the ridge tops and the canyon bottoms.
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Rockslide
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Causes
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Mass-wasting occurs whenever the gravitational force on the rock exceeds the ability of the slope to resist that force. Therefore, anything that erodes or impedes the mountain's ability to resist this force may be one of the causes of mass-wasting. While a major event such as an earthquake can cause large rockslides to happen, a majority of slides occur due to a combination of gravitational pressure and erosional influences.
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Rockslide
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Causes
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Amongst these erosional properties, water is arguably the most effective geologic agent that causes mass-wasting events to occur. Water aids in the downslope movement of surface material by adding weight to the soil and by filling pores which tends to push apart individual grains, decreasing the resistance of the material to movement. While these processes can cause a slide to happen, the speed and potential devastation of a rockslide is often determined by the severity of steepness presented by the failing slope.
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Rockslide
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Disaster prevention
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With increasing populations in rural areas around the world, the hazards presented by potential rock slides are becoming more of a pressing issue moving forward. Luckily, individuals working in the fields of geologic science and engineering continue to perfect methods of rock slide detection, assessment, and warning. New earth observation tools have supplied a much enhanced ability to detect potential rock slide hazards. Analysis of sequential InSAR and LiDAR data provides a very valuable regional view of slope movement. Once susceptible areas are discovered, detailed analysis can be carried out at the specific site. These assessments are used to determine the amount of material that will be released as well as the speed at which this material will be transported.
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Rockslide
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Disaster prevention
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Once a site is deemed hazardous, different types of geologic engineering techniques are used in order to prevent the compromised slope from failing. Some of these designs are listed below.
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Rockslide
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Disaster prevention
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Wire meshing A corrosion resistant material that is installed at the crest and foot of the slope. This insures that any falling debris is trapped behind the mesh.Retaining walls One of the oldest forms of ground engineering, retaining walls are built in order to neutralize the effects of unstable slopes by holding fallen rocks and soil back from roads and other structures.Soil nailing An economical method of constructing a form of retaining wall from the top of a slope down. In this process closely spaced steel tendons are drilled into the soil. These nails significantly increase the cohesion of soil through the ability of these rods to carry tensile loads. these steel beams are usually reinforced through the use of welded wire mesh.Rock bolting Rock bolts are always a primary means of reinforcement, Bolts are placed in a specific pattern in order to transfer the faces load from the slopes exterior, to its interior.
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Fresh water skin disease
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Fresh water skin disease
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Fresh water skin disease (FWSD) is a disease of marine cetaceans in coastal and estuarine environments, caused when they are exposed for extended periods to water with lower than normal levels of salt (hypo-saline). It has been observed in dolphins that were displaced into freshwater lakes, and in normally-salty lakes and estuaries where salinity has dropped suddenly due to flooding or storm runoff.The symptoms are widespread skin lesions and ulcers. Circular lesions can resemble cetacean pox, which is more common in juveniles. Chronic lesions may have overgrowths of algal and/or fungal mats. Extended exposure can lead to over-hydration, electrolyte imbalance, and organ failure.The syndrome has been observed particularly with bottlenose dolphins Tursiops truncatus in Lake Pontchartrain, Louisiana from 2007, thought to have been trapped by Hurricane Katrina in 2005; with T. australis at Gippsland Lakes in 2007; with T. aduncus at the Swan Canning Riverpark (Swan and Canning rivers) in 2009; and with T. truncatus in Texas following Hurricane Harvey in 2017. In the Gippsland Lakes, the sudden decrease in salinity followed a slow build-up during ten years of drought. Plaques or ulcers have also been observed in the Chilean dolphin (Cephalorhynchus eutropia) in Patagonia, Guiana dolphins (Sotalia guianensis) in Brazil, and a pair of a humpback whales (Megaptera novaengliae) in northern California. The histology and pathology from dolphins that died in the 2007 and 2009 Australian events was published in 2020, with the name "fresh water skin disease".
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Half knot
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Half knot
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Half knot may refer to the overhand knot, as it forms the first half of a reef knot, thief knot, granny knot, grief knot, or: Half-Windsor knot Half blood knot Half hitch (Two half-hitches)
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Fondant potatoes
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Fondant potatoes
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Fondant potatoes, or pommes fondant, is a method of preparing potatoes that traditionally involves cutting them into cylinders, browning the ends, and then slowly roasting the potatoes in butter and stock.
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Cefditoren
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Cefditoren
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Cefditoren, also known as cefditoren pivoxil is an antibiotic used to treat infections caused by Gram-positive and Gram-negative bacteria that are resistant to other antibiotics. It is mainly used for treatment of community acquired pneumonia. It is taken by mouth and is in the cephalosporin family of antibiotics, which is part of the broader beta-lactam group of antibiotics.
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Cefditoren
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Structure
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Like other cephalosporins, cefditoren has a β-lactam ring at the 7 position of cephalosporin ring that is responsible for its inhibitory action on bacterial cell wall synthesis. In addition to the cephem nucleus common to all cephalosporins, cefditoren has an aminothiazole group that enhances its activity against Gram-negative organisms, a methylthiazole group that enhances its activity against Gram-positive organisms, a methoxyimino group that gives it stability against β-lactamases, and a pivoxil ester group that enhances oral bioavailability.
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Cefditoren
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Antimicrobial activity
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The spectrum of cefditoren includes both Gram-positive and Gram-negative bacterial species. It has strong antimicrobial activity because of its high affinity for penicillin binding protein 2X, which responsible for cephalosporin resistance when mutated. Cefditoren pivoxil high intrinsic activity against Streptococcus pneumoniae, including penicillin-resistant strains. Cefditoren holds a balanced antimicrobial spectrum that includes the three major pathogens of community-acquired lower-respiratory tract infections: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Aerobic Gram-positive microorganisms: Staphylococcus aureus (methicillin-susceptible strains, including β-lactamase-producing strains), Streptococcus pneumoniae, Streptococcus pyogenes Aerobic Gram-negative microorganisms: Haemophilus influenzae (including β-lactamase-producing strains), Haemophilus parainfluenzae (including β-lactamase-producing strains), Moraxella catarrhalis (including β-lactamase-producing strains.
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Cefditoren
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Pharmacokinetics
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Absorption Oral bioavailability: following oral administration, cefditoren pivoxil is absorbed from the gastrointestinal tract and hydrolyzed to cefditoren by esterases. Maximal plasma concentrations of cefditoren under fasting conditions average 1.8 ± 0.6 µg/mL following 200 mg dose and occur 1.5 to 3 hours following dosing. Cefditoren does not accumulate in plasma following twice daily administration to subjects with normal renal function. Under fasting conditions, the estimated absolute bioavailability of cefditoren pivoxil is approximately 14%.
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Cefditoren
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Pharmacokinetics
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Distribution Binding of cefditoren to plasma proteins averages 88%, and the mean volume of distribution of cefditoren at steady state is 9.3L. Cefditoren has been shown to penetrate into bronchial mucosa, epithelial lining fluid, skin blister fluid and tonsillar tissue and clinically relevant concentrations against common pathogens are achieved in these tissues for at least 4 hours.
Metabolism and Excretion Cefditoren is predominantly eliminated by the kidneys as unchanged drug and has a renal clearance of 4.1–5.6 L/h after multiple doses; its elimination half-life is 1.5 hours.
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Cefditoren
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Medical uses
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Cefditoren pivoxil is indicated to treat uncomplicated skin and skin structure infections, community-acquired pneumonia, acute bacterial exacerbation of chronic bronchitis, pharyngitis, and tonsillitis, acute maxillary sinusitis, otitis media (indications may differ in some countries).
Spectrum of bacterial susceptibility Cefditoren pivoxil has a broad spectrum of activity and has been used to treat bacterial infections of the skin and respiratory tract, including bronchitis, pneumonia, and tonsillitis. The following represents minimum inhibitory concentration data for several medically significant microorganisms.
Haemophilus influenzae: ≥0.063 – 0.25 μg/ml Staphylcoccus aureus: 0.25 – >128 μg/ml (not includes methicillin-resistant Staphylococcus aureus) Streptococcus pyogenes: ≤0.004 – 2 μg/mlCefditoren does not have antibacterial activity against Pseudomonas aeruginosa.
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Cefditoren
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Dosage and administration
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Adults and Adolescents (≥12 Years) Community-acquired pneumonia: 400 mg twice daily for 14 days Acute bacterial exacerbation of chronic bronchitis: 400 mg twice daily for 10 days Pharyngitis/tonsillitis, otitis media, sinusitis: 200 mg twice daily for 10 days Uncomplicated skin and skin structure infections: 200 mg twice daily for 10 days Children (2 months to 12 years of age) Pneumonia, otitis media or sinusitis: 3 mg/kg/dose, 3 times a day, after meals. The dosage may be increased up to 6 mg/kg/dose as needed, but not exceed the maximum dose for adults.
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Cefditoren
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Dosage and administration
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For children with diseases other than above: 3 mg/kg/dose, 3 times a day after meals. The dosage may be adjusted according to the disease or the patients age and symptoms, but not exceed the maximum dose for adults. Safety in low birth weight infants and newborns has not been established.
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Cefditoren
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Pregnancy
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Pregnancy Category B Cefditoren pivoxil was not teratogenic up to the highest doses tested in rats and rabbits. In rats, this dose was 1000 mg/kg/day, which is approximately 24 times a human dose of 200 mg twice daily based on mg/m2/day. In rabbits, the highest dose tested was 90 mg/kg/day, which is approximately four times a human dose of 200 mg twice daily based on mg/m2/day. This dose produced severe maternal toxicity and resulted in fetal toxicity and abortions.
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Cefditoren
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Pregnancy
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In a postnatal development study in rats, cefditoren pivoxil produced no adverse effects on postnatal survival, physical and behavioral development, learning abilities, and reproductive capability at sexual maturity when tested at doses of up to 750 mg/kg/day, the highest dose tested. This is approximately 18 times a human dose of 200 mg twice daily based on mg/m2/day. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
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Cefditoren
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Geriatric use
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Of the 2675 patients in clinical studies who received cefditoren pivoxil 200 mg twice daily, 308 (12%) were >65 years of age. Of the 2159 patients in clinical studies who received cefditoren pivoxil 400 mg twice daily, 307 (14%) were >65 years of age. No clinically significant differences in effectiveness or safety were observed between older and younger patients. No dose adjustments are necessary in geriatric patients with normal renal function. This drug is substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.
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Cefditoren
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International approvals
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Cefditoren pivoxil is available as 200 and 400 mg tablets in the United States. It was marketed under the trade name Spectracef by Vansen Pharma Inc. Cefditoren is also marketed under the name Meiact by Meiji Seika Pharma Co., Ltd. In India it is marketed under the brand name Zostum-O by Zuventus Healthcare.
Proprietary Preparations and Countries US:Spectracef; India:Zostum-O; Japan:Meiact; Russia:Spectracef; China:Meiact; Greece:Spectracef; Indonesia:Meiact; Italy:Giasion; Mexico:Spectracef; Portugal:Meiact; Thailand:Meiact; Turkey: Cftiten, Meiact; Sefporin Spain: Spectracef, Meiact.
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Cefditoren
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Contraindications
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In patients with known allergy to the cephalosporin class of antibiotics or any of its components.
Patients with carnitine deficiency or inborn errors of metabolism that may result in clinically significant carnitine deficiency, because use of cefditoren causes renal excretion of carnitine.
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Cefditoren
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Safety and tolerability
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Cefditoren pivoxil is generally well-tolerated, with most adverse events being of mild-to-moderate severity and self-limiting. Gastrointestinal adverse events (e.g., diarrhoea, nausea and abdominal pain) were the most commonly reported adverse events, although they seldom led to treatment discontinuation.
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Cefditoren
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Safety and tolerability
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In a post-marketing surveillance evaluating safety in 2006 children with acute otitis media treated with cefditoren (median daily dose: 10.0 mg/kg with a median total treatment period of 7 days), the incidence of adverse reactions was 1.79%, without unexpected or serious adverse drug reactions reported. The most frequent adverse drug reaction was diarrhea (1.30%) that resolved or subsided during treatment or after discontinuation or completion of therapy in all cases.
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Cefditoren
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Safety and tolerability
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Data from the clinical studies carried out with cefditoren in the treatment of pharyngotonsillitis from 2007 to 2010 in Japan showed that the percentage of adverse events was very low and diarrhea was the most frequent event. In the largest study (734 children), the incidence of adverse reactions was 1.50% (11 events in 11 patients), with 3 events of diarrhea and three of hematuria in urinalysis without clinical symptoms. In a study carried out in children in Thailand comparing cefditoren (66 patients) with amoxicillin/clavulanic acid (72 patients) for 10 days in the treatment of acute bacterial rhinosinusitis, the most frequent adverse event was diarrhea, with significant (P = 0.02) differences in the percentages found for both compounds (4.5% with cefditoren vs. 18.1% for amoxicillin/clavulanic acid).
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Cefditoren
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Guidelines
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Japanese Guidelines Japanese guidelines for the management of respiratory infectious diseases in children recommend cefditoren pivoxil as an initial antimicrobial therapy in children (2 months and older).
A panel of 70 pulmonologists, coordinated by 9 experts in respiratory care recommendations A consensus on appropriate prescribing in lower respiratory tract infection therapy was appraised by Delphi exercise, based on a panel of 70 pulmonologists, coordinated by a scientific committee of nine experts in respiratory medical care.
Amongst 3rd-generation oral cephalosporins, cefditoren pivoxil has the highest intrinsic activity against Streptococcus pneumoniae, penicillin-resistant strains included.
Amongst 3rd-generation oral cephalosporins, the spectrum of cefditoren is particularly balanced, includes both Gram-positive and Gram-negative species.
The experts expressed the opinion that, due to its high intrinsic activity, cefditoren appears as an appropriate agent for either the treatment of lower respiratory tract infections and for parenteral to oral switch therapy as well.
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Cefditoren
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Ideal for switch therapy
|
The characteristics of oral antibiotics to be considered for the switch therapy (parenteral to oral antibiotic) are: (i) similar antimicrobial spectrum, (ii) high bioavailability, (iii) administration time 12–24 hours, (iv) good tolerability The expert panel reached a high level of consensus on cefditoren pivoxil as the most appropriate option for the switch therapy from parenteral third-generation cephalosporins (like cefotaxime or ceftriaxone) to oral therapy, because of the similar spectrum and the highest intrinsic activity.
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The Wavewatcher's Companion
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The Wavewatcher's Companion
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The Wavewatcher's Companion is a 2010 science book by Gavin Pretor-Pinney.
The book was the 2011 winner of the Royal Society Winton Prize for Science Books.
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The Wavewatcher's Companion
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Theme
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The book is a wide-ranging discussion on waves in all their forms and how waves are such an intimate part of our lives.
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The Wavewatcher's Companion
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Theme
|
The book's topics include: waves that exist within our bodies; the waves that give rise to music and colour; the waves that drive the information age; and the waves of nature, of the earth, sea and air.As Jennifer Ouellette of the Wall Street Journal describes, Pretor-Pinney 'employs a chatty, conversational tone, with clear technical explanations enlivened by real-world examples, whimsical asides, personal anecdotes and inventive analogies' to explain his subject.
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The Wavewatcher's Companion
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Reception
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The book was well received on its publication. Victoria Segal of The Guardian enthused that Pretor-Pinney "has the gifted teacher's knack for finding the right metaphor to hook the attention". Toby Clements of the Daily Telegraph felt it was a worthy sequel to Pretor-Pinney's previous surprise best-seller, 'The Cloudspotter's Guide.The book was the 2011 winner of the Royal Society Winton Prize for Science Books, the prestigious award for science writing.
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The Wavewatcher's Companion
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Reception
|
Richard Holmes, the Chair of judging panel, said it was a 'highly unusual and outstandingly effective piece of popular science writing and that Pretor-Pinney "had managed to use relatively straight-forward science to transform the readers' perspective of the world around them". Richard Holmes noted the importance of the award stating “Popular science is an increasingly important genre, and this is an increasingly important prize".
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Flying height
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Flying height
|
The flying height or floating height or head gap is the distance between the disk read/write head on a hard disk drive and the platter. The first commercial hard-disk drive, the IBM 305 RAMAC (1956), used forced air to maintain a 0.002 inch (51 μm) between the head and disk. The IBM 1301, introduced in 1961, was the first disk drive in which the head was attached to a "hydrodynamic air bearing slider," which generates its own cushion of pressurized air, allowing the slider and head to fly much closer, 0.00025 inches (6.35 μm) above the disk surface.In 2011, the flying height in modern drives was a few nanometers (about 5 nm). Thus, the head can collide with even an obstruction as thin as a fingerprint or a particle of smoke. Despite the dangers of hard drive failure from such foreign objects, hard drives generally allow for ventilation (albeit through a filter) so that the air pressure within the drive can equalize with the air pressure outside. Because disk drives depend on the head floating on a cushion of air, they are not designed to operate in a vacuum. Regulation of flying height will become even more important in future high-capacity drives.However, hermetically sealed enclosures are beginning to be adopted for hard drives filled with helium gas, with the first products launched in December 2015, starting with capacities of 10 TB.
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Dual-motor, four-wheel-drive layout
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Dual-motor, four-wheel-drive layout
|
In automotive design, dual-motor, four-wheel-drive layout is mainly used by battery electric vehicles by placing electric motors on both front and rear axles and drives all four roadwheels, creating a four-wheel drive layout. This layout is made possible by the small size of electric motors compared to internal combustion engines, allowing it to be placed in multiple locations. It also eliminates the need of a drive shaft that are commonly used by conventional four-wheel drive vehicles to create space for batteries that are commonly mounted on the floor of electric vehicles.The layout is also beneficial to distribute available electrical horsepower to maximize torque and power in response to road grip conditions and weight transfer in the vehicle. For example, during hard acceleration, the front motor must reduce torque and power in order to prevent the front wheels from spinning as weight transfers to the rear of the vehicle. The excess power is transferred to the rear motor where it can be used immediately. The opposite applies when braking, when the front motor can accept more regenerative braking torque and power.In addition, electric vehicles may be equipped with more than two electric motors to achieve greater power output and superior handling. The first mass-produced triple-motor layout was introduced on the Audi e-tron in 2020, which consists of one motor at the front and two motors at the rear.
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Testosterone decanoate
|
Testosterone decanoate
|
Testosterone decanoate (BAN) is an androgen and anabolic steroid and a testosterone ester. It is a component of Sustanon, along with testosterone propionate, testosterone phenylpropionate, and testosterone isocaproate. The medication has not been marketed as a single-drug preparation. Testosterone decanoate has been investigated as a potential long-acting injectable male contraceptive. It has a longer duration of action than testosterone enanthate, but its duration is not as prolonged as that of testosterone undecanoate.
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TF-1 cell
|
TF-1 cell
|
TF-1 cells are immortal cell line derived from the human Erythroleukemia used in biomedical research. This cells are proliferatively responsive to interleukin-3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF). TF-1 cells have gene fusion of CBFA2T3-ABHD12.
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Panna cotta
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Panna cotta
|
Panna cotta (Italian for "cooked cream") is an Italian dessert of sweetened cream thickened with gelatin and molded. The cream may be aromatized with coffee, vanilla, or other flavorings.
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Panna cotta
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History
|
The name panna cotta is not mentioned in Italian cookbooks before the 1960s, yet it is often cited as a traditional dessert of the northern Italian region of Piedmont. One unverified story says that it was invented by a Hungarian woman in the Langhe in the early 1900s. An 1879 dictionary mentions a dish called latte inglese ("English milk"), made of cream cooked with gelatin and molded, though other sources say that latte inglese is made with egg yolks, like crème anglaise; perhaps the name covered any thickened custard-like preparation.
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Panna cotta
|
History
|
The dish might also come from the French recipe of fromage bavarois from Marie-Antoine Carême. Actually, this recipe that we can find in le pâtissier royal parisien is the same as the modern panna cotta with the difference that one part of the cream is whipped to make chantilly and included to the preparation before adding the gelatin.The Region of Piedmont includes panna cotta in its 2001 list of traditional food products. Its recipe includes cream, milk, sugar, vanilla, gelatin, rum, and marsala poured into a mold with caramel. Another author considers the traditional flavoring to be peach eau-de-vie, and the traditional presentation not to have sauce or other garnishes.Panna cotta became fashionable in the United States in the 1990s.
|
Panna cotta
|
Preparation
|
Sugar is dissolved in warm cream. The cream may be flavored by infusing spices and the like in it or by adding rum, coffee, vanilla, and so on. Gelatin is dissolved in a cold liquid (usually water), then added to the warm cream mixture. This is poured into molds and allowed to set. The molds may have caramel in the bottoms, giving a result similar to a crème caramel. After it solidifies, the panna cotta is usually unmolded onto a serving plate.
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Panna cotta
|
Preparation
|
Although the name means 'cooked cream', the ingredients are only warm enough to dissolve the gelatin and sugar. Italian recipes sometimes call for colla di pesce 'fish glue,' which may literally be isinglass or, more likely, simply a name for common gelatin.
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Panna cotta
|
Garnishes
|
Panna cotta is often served with a coulis of berries or a sauce of caramel or chocolate. It may be covered with other fruits or liqueurs.
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Panna cotta
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Related dishes
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Bavarian cream is similar to panna cotta but usually includes eggs as well as gelatin and is mixed with whipped cream before setting.Blancmange is sometimes thickened with gelatin or isinglass, and sometimes with cornstarch.Panna cotta is sometimes called a custard, but true custard is thickened with egg yolks, not gelatin. A lighter version substitutes cream with Greek yogurt.
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Baud
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Baud
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In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel.
It is the unit for symbol rate or modulation rate in symbols per second or pulses per second. It is the number of distinct symbol changes (signalling events) made to the transmission medium per second in a digitally modulated signal or a bd rate line code.
Baud is related to gross bit rate, which can be expressed in bits per second. If there are precisely two symbols in the system (typically 0 and 1), then baud and bit per second (bit/s) are equivalent.
|
Baud
|
Naming
|
The baud unit is named after Émile Baudot, the inventor of the Baudot code for telegraphy, and is represented according to the rules for SI units. That is, the first letter of its symbol is uppercase (Bd), but when the unit is spelled out, it should be written in lowercase (baud) except when it begins a sentence.
It was defined by the CCITT (now the ITU) in November 1926. The earlier standard had been the number of words per minute, which was a less robust measure since word length can vary.
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Baud
|
Definitions
|
The symbol duration time, also known as the unit interval, can be directly measured as the time between transitions by looking at an eye diagram of the signal on an oscilloscope. The symbol duration time Ts can be calculated as: Ts=1fs, where fs is the symbol rate.
There is also a chance of miscommunication which leads to ambiguity.
|
Baud
|
Definitions
|
Example: Communication at the baud rate 1000 Bd means communication by means of sending 1000 symbols per second. In the case of a modem, this corresponds to 1000 tones per second; similarly, in the case of a line code, this corresponds to 1000 pulses per second. The symbol duration time is 1/1000 second (that is, 1 millisecond).In digital systems (i.e., using discrete/discontinuous values) with binary code, 1 Bd = 1 bit/s. By contrast, non-digital (or analog) systems use a continuous range of values to represent information and in these systems the exact informational size of 1 Bd varies.
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Baud
|
Definitions
|
The baud is scaled using standard metric prefixes, so that for example 1 kBd (kilobaud) = 1000 Bd 1 MBd (megabaud) = 1000 kBd 1 GBd (gigabaud) = 1000 MBd
|
Baud
|
Relationship to gross bit rate
|
The symbol rate is related to gross bit rate expressed in bit/s.
|
Baud
|
Relationship to gross bit rate
|
The term baud has sometimes incorrectly been used to mean bit rate, since these rates are the same in old modems as well as in the simplest digital communication links using only one bit per symbol, such that binary digit "0" is represented by one symbol, and binary digit "1" by another symbol. In more advanced modems and data transmission techniques, a symbol may have more than two states, so it may represent more than one bit. A bit (binary digit) always represents one of two states.
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Baud
|
Relationship to gross bit rate
|
If N bits are conveyed per symbol, and the gross bit rate is R, inclusive of channel coding overhead, the symbol rate fs can be calculated as fs=RN.
By taking information per pulse N in bit/pulse to be the base-2-logarithm of the number of distinct messages M that could be sent, Hartley constructed a measure of the gross bit rate R as R=fsN where log 2(M)⌉.
Here, the ⌈x⌉ denotes the ceiling function of x . Where x is taken to be any real number greater than zero, then the ceiling function rounds up to the nearest natural number (e.g. 2.11 ⌉=3 ).
|
Baud
|
Relationship to gross bit rate
|
In that case, M = 2N different symbols are used. In a modem, these may be time-limited sinewave tones with unique combinations of amplitude, phase and/or frequency. For example, in a 64QAM modem, M = 64, and so the bit rate is N = log2(64) = 6 times the baud rate. In a line code, these may be M different voltage levels.
|
Baud
|
Relationship to gross bit rate
|
The ratio is not necessarily even an integer; in 4B3T coding, the bit rate is 4/3 of the baud rate. (A typical basic rate interface with a 160 kbit/s raw data rate operates at 120 kBd.) Codes with many symbols, and thus a bit rate higher than the symbol rate, are most useful on channels such as telephone lines with a limited bandwidth but a high signal-to-noise ratio within that bandwidth. In other applications, the bit rate is less than the symbol rate. Eight-to-fourteen modulation as used on audio CDs has bit rate 8/17 of the baud rate.
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Library Freedom Project
|
Library Freedom Project
|
The Library Freedom Project teaches librarians about surveillance threats, privacy rights, and digital tools to thwart surveillance. In 2015 the Project began an endeavour to place relays and, particularly, exit nodes of the Tor anonymity network in public libraries.
|
Library Freedom Project
|
Tor Exit Relay Project
|
Its pilot project enabled the Kilton Public Library in Lebanon, New Hampshire to become in July 2015 the first library in the United States to host Tor, running a middle relay on its excess bandwidth. This service was put on hold in early September, however, when the library was visited by the local police department after they had received a "heads up" e-mail from Department of Homeland Security highlighting the criminal uses of the Tor network (and which falsely claimed that this was the network's primary usage), whereupon the library began reconsidering the deployment from a public relations perspective.After an outpouring of support from the Electronic Frontier Foundation, the Massachusetts and New Hampshire affiliates of the ACLU, the Tor Project itself, an editorial in the local paper Valley News strongly in favor of the pilot project, and virtually unanimous public testimony, the library board of trustees decided on 15 September 2015 to renew the anonymity service, letting stand its previous unanimous vote to establish the middle relay. A dozen libraries and their supporters nationwide expressed interest hosting their own nodes after the DHS involvement became public (an example of the Streisand effect), and U.S. Rep. Zoe Lofgren (D-Calif) released a letter on 10 December 2015, in which she asked the DHS to clarify its procedures, stating that “While the Kilton Public Library’s board ultimately voted to restore their Tor relay, I am no less disturbed by the possibility that DHS employers are pressuring or persuading public and private entities to discontinue or degrade services that protect the privacy and anonymity of U.S. citizens.”In March 2016, New Hampshire state representative Keith Ammon introduced a bill allowing public libraries to run privacy software such as Tor which specifically referenced Tor itself. The bill was crafted with extensive input from Library Freedom director Alison Macrina, and was the direct result of the Kilton Public Library imbroglio. The bill was passed by the House 268-62.Also in March 2016, the first Tor middle relay at a library in Canada was established, at the University of Western Ontario. Given that the running of a Tor exit node is an unsettled area of Canadian law, and that institutions are more capable than individuals to cope with legal pressures, Alison Macrina has opined that in some ways she would like to see intelligence agencies and law enforcement attempt to intervene in the event that an exit node were established.Also in March 2016, the Library Freedom Project was awarded the Free Software Foundation's 2015 Free Software Award for Projects of Social Benefit at MIT.As of 26 June 2016, the Kilton Library is the only library in the U.S. running a Tor exit node. However, in August of that same year, Kilton Library's IT Manager, Chuck McAndrew, said they still hoped other libraries would run their own, adding, "We always planned on our library simply being the pilot for a larger nationwide program. Like everything, this will take time. We continue to talk to other libraries, and the Library Freedom Project is actively working with a number of libraries that have an interest in participating."
|
Library Freedom Project
|
Workshops
|
Working with ACLU affiliates across the United States, the Library Freedom Project provides workshops to educate librarians about "some of the major surveillance programs and authorizations, including the USA PATRIOT Act, section 702 of the FISA Amendments Act, PRISM, XKEYSCORE, and more, connecting the NSA’s dragnet with FBI and local police surveillance". They also discuss current and developing privacy law on both the federal and state levels, in addition to advising librarians how to handle issues like gag orders and National Security Letters. Other topics covered include Privacy Enhancing Technology (PET) that might help library patrons browse anonymously or evade online tracking.
|
Library Freedom Project
|
Workshops
|
Furthermore, the project conducts training classes for library patrons themselves which focus on on-line security and privacy. The classes can be adjusted to accommodate any level of user, from beginner to advanced, and various security needs. Given that library patrons, including but not limited to domestic violence survivors, political activists, whistle blowers, journalists, and LGBT teens or adults in many communities, face various threat models, the gestalt of digital security is not a matter of one-size-fits-all. In this regard Alison Macrina has remarked at a library conference that " “Digital security isn’t about which tools you use; rather, it’s about understanding the threats you face and how you can counter those threats. To become more secure, you must determine what you need to protect, and whom you need to protect it from. Threats can change depending on where you’re located, what you’re doing, and whom you’re working with.”The Library Freedom Project is a member of the torservers.net network, an organization of nonprofits which specializes in the general establishment of exit nodes via workshops and donations.
|
Library Freedom Project
|
Library Freedom Institute
|
Beginning in 2018, Library Freedom Project began offering the Library Freedom Institute as a joint partnership with New York University. The institute is "a free, privacy-focused... program for librarians to teach them the skills necessary to thrive as Privacy Advocates; from educating community members to influencing public policy." The format of the Institute has changed slightly with each cohort, but lasts four to six months and features lecturers and discussions in the areas of technology, community building, media, activism, and education. Participants create capstone projects at the end of the course. Since its inception, the Library Freedom Institute has been supported by grants from the Institute of Museum and Library Services.
|
Library Freedom Project
|
Library Freedom Institute
|
As of July 2020, there have been four cohorts of Library Freedom Institute with over 100 graduates from the program.
|
Library Freedom Project
|
Funding
|
In January 2015 the Library Freedom Project received $244,700 in grant funding from the Knight Foundation, and in January 2016 $50,000 from the Rose Foundation's Consumer Privacy Rights Fund (the fiscal sponsor of that grant being the Miami Foundation).In August 2017 the Library Freedom Project was awarded a $249,504 grant from the Laura Bush 21st Century Librarian Program to facilitate the use of practical privacy tools in libraries using a "training the trainers" model. 40 geographically dispersed Privacy Advocates are expected to be trained in a six month course. New York University (NYU) and the Library Freedom Project have since created a formal collaborative program funded by the Institute of Museum and Library Services called Library Freedom Institute; its inaugural course began in June 2018.
|
Sulfur oxygenase/reductase
|
Sulfur oxygenase/reductase
|
In enzymology, a sulfur oxygenase/reductase (EC 1.13.11.55) is an enzyme that catalyzes the chemical reaction 4 sulfur + 4 H2O + O2 ⇌ 2 hydrogen sulfide + 2 bisulfite + 2 H+The 3 substrates of this enzyme are sulfur, H2O, and O2, whereas its 3 products are hydrogen sulfide, bisulfite, and H+.
|
Sulfur oxygenase/reductase
|
Sulfur oxygenase/reductase
|
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O2. The systematic name of this enzyme class is sulfur:oxygen oxidoreductase (hydrogen-sulfide- and sulfite-forming). Other names in common use include SOR, sulfur oxygenase, and sulfur oxygenase reductase.
|
Open Source Tripwire
|
Open Source Tripwire
|
Open Source Tripwire is a free software security and data integrity tool for monitoring and alerting on specific file change(s) on a range of systems. The project is based on code originally contributed by Tripwire, Inc. in 2000.
|
Duospaced font
|
Duospaced font
|
A duospaced font (also called a duospace font) is a fixed-width font whose letters and characters occupy either of two integer multiples of a specified, fixed horizontal space. Traditionally, this means either a single or double character width, although the term has also been applied to fonts using fixed character widths with another simple ratio between them.These dual character widths are also referred to as half-width and full-width, where a full-width character occupies double the width of a half-width character. This contrasts with variable-width fonts, where the letters and spacings have more than two different widths. And, unlike monospaced fonts, this means a character can occupy up to two effective character widths instead of a single character width. This extra horizontal space allows for the accommodation of wider glyphs, such as large ideographs, that cannot reasonably fit into the single character width of strictly uniform, monospaced font.
|
Duospaced font
|
In CJK typography
|
The idea of a "duospaced" font came from East Asian typography, where the local scripts of CJK characters simply cannot fit into a narrow column used in Latin fixed-pitch fonts. Note that this "duospace" name is mostly a historical (c. 1990) Western distinction; Asian typefaces with such characteristics simply call themselves "monospaced" or "fixed pitch".CJK monospace fonts typically include halfwidth and fullwidth forms of characters that provide different widths for typesetting. In addition to East Asian characters and such forms, it is common for other technical and pictographic symbols to become duospaced in some East Asian fonts, a phenomenon known as "ambiguous width".It is a common pitfall for Western programmers to neglect support for such fonts: Terminal applications may have misaligned output due to assuming all character "pitch" to be 1 column wide. The wcwidth() function, originally part of POSIX, is available for querying the width of characters.
|
Duospaced font
|
In CJK typography
|
Qt has a bug where it fails to list CJK monospaced fonts because the underlying fontconfig defined "monospace" as "fixed-pitch" fonts.With the exception of some Japanese monospace fonts like Source Han Code JP, where a 1.5× width is used as the ideograph width, almost all CJK monospace fonts use 2× as the ideograph width. (In the case of the Korean language, Hangul characters which are usually slightly narrower than the ideographs are made to match them.) Some CJK monospace fonts with two or more widths are: Andale Duospace WT GNU Unifont (pan-character set) Migu 1M, Migu 2M Monotype Sans Duospace WT Thorndale Duospace WT WorldType Sans Duo, WorldType Serif Duo Source Han Code JP (1.5×) WenQuanYi Micro Hei Mono, WenQuanYi Zen Hei Mono
|
Duospaced font
|
In Western typography
|
Western duospaced fonts are similar in purpose to CJK duospaced fonts, but they are much rarer and less supported. The idea seems to be limited to an iA Writer typeface where the latin characters wmWM have 1.5× widths, so that they retain the traditional letter shape better.
|
Acquired C1 esterase inhibitor deficiency
|
Acquired C1 esterase inhibitor deficiency
|
Acquired C1 esterase inhibitor deficiency, also referred to as acquired angioedema (AAE), is a rare medical condition that presents as body swelling that can be life-threatening and manifests due to another underlying medical condition.: 153 The acquired form of this disease can occur from a deficiency or abnormal function of the enzyme C1 esterase inhibitor (C1-INH). This disease is also abbreviated in medical literature as C1INH-AAE. This form of angioedema is considered acquired due to its association with lymphatic malignancies, immune system disorders, or infections. Typically, acquired angioedema presents later in adulthood, in contrast to hereditary angioedema which usually presents from early childhood and with similar symptoms.Acquired angioedema is usually found after recurrent episodes of swelling and can in some cases take several months to diagnose. Diagnosis usually consists of medical evaluation in addition to laboratory testing. Laboratory evaluation includes complement studies, in which typical cases demonstrate low C4 levels, low C1q levels, and normal C3 levels. Determining the etiology, or cause, of acquired angioedema is often helpful in providing appropriate management of AAE.
|
Acquired C1 esterase inhibitor deficiency
|
Acquired C1 esterase inhibitor deficiency
|
Management of AAE usually includes treating any underlying disorder that could be responsible for the condition. Additionally, symptom management is important, especially in cases that are life-threatening. There are medications available to treat AAE, which are focused on replacing deficient levels of C1-INH or abnormal C1-INH enzymes. There are some cases of partial improvement and full resolution with treatment of the underlying medical problems contributing to AAE.
|
Acquired C1 esterase inhibitor deficiency
|
Epidemiology
|
It is estimated that the worldwide prevalence of AAE ranges from 1 person in every 10,000 people are affected to 1 case in every 150,000 people. However, it is thought that this disease prevalence could be higher due to diagnostic oversight and the shared symptoms of acquired angioedema with similar diseases. This disease tends to affect males and females equally. Additionally, individuals with acquired angioedema usually develops symptoms in their fourth decade of life or older. Of note, Saini reports the difficulty of diagnosing angioedema accurately due to certain challenges. These obstacles include the lack of awareness about angioedema presentation and potentially higher than expected worldwide prevalence. More challenges include the similarities to paraneoplastic disorders that often require higher priority of care, the evolution of symptoms over time, and mild cases might be attributed to medication use or allergic reactions from an individual's existing medical history. As a result, accurate diagnosis of AAE can take several months, which can delay targeted and specific treatment.
|
Acquired C1 esterase inhibitor deficiency
|
Causes
|
There are various disease comorbidities associated with acquired C1 esterase inhibitor deficiency, including: Lymphoproliferative disorders and lymphatic malignancies Lymphoproliferative disorders, such as monoclonal gammopathy of undetermined significance (MGUS) and non-Hodgkin lymphoma are associated with acquired angioedema. In cohort studies, MGUS is considered one of the most common disorders associated with AAE. MGUS is a premalignant plasma cell disorder that is associated with bone marrow pathologic changes leading to abnormal production of M protein that can progress to other hematologic diseases. Additionally, through retrospective case studies performed in France, Gobert et al. found that non-Hodgkin lymphoma was associated with 48% of cases in a sample size of 92 cases of acquired angioedema.
|
Acquired C1 esterase inhibitor deficiency
|
Causes
|
Multiple myeloma (MM) is a malignant plasma cell disorder that progresses from MGUS. MM is characterized by elevated monoclonal paraprotein in addition to end organ damage, such as kidney failure.
Lymphoplasmacytic lymphoma (also known as Waldenström macroglobulinemia) is a B cell malignancy with hematologic changes that affect the lymphatic system. Some of the clinical manifestations seen in this lymphoma are anemia, hyperviscosity syndrome, and neuropathy.
Autoimmune disorders Autoimmune disorders, such as systemic lupus erythematosus (SLE) are observed with AAE. SLE is an autoimmune disease with variable manifestations from mild symptoms to multiorgan involvement. The autoantibody component involved in SLE has been investigated and is thought to be associated with angioedema manifestations.
|
Acquired C1 esterase inhibitor deficiency
|
Causes
|
Certain vasculitic diseases, such as eosinophilic granulomatosis with polyangiitis (also known as Churg–Strauss syndrome) have been associated with AAE. Eosinophilic granulomatosis with polyangiitis (EGPA) is an inflammatory disease characterized by necrotizing vasculitis that affects small and medium-sized vessels of the body. This vasculitis is associated with certain comorbidities including asthma, rhinosinusitis, and eosinophilia (blood cells responsible for activating immune responses and downstream signals in inflammation).
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