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Tampon tax
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Tampon tax
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Tampon tax (or period tax) is a popular term used to call attention to tampons, and other feminine hygiene products, being subject to value-added tax (VAT) or sales tax, unlike the tax exemption status granted to other products considered basic necessities. Proponents of tax exemption argue that tampons, sanitary napkins, menstrual cups and comparable products constitute basic, unavoidable necessities for women, and any additional taxes constitute a pink tax.
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Tampon tax
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Tampon tax
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Proponents of tax exemption argue that tampons, sanitary napkins, menstrual cups and other products which serve the basic menstrual cycle constitute unavoidable necessities for women and should be classified alongside other unavoidable, tax-exempt necessities, such as groceries and personal medical items. The BBC estimates that women need to use feminine hygiene products for about a week each month for about 30 years. According to the American Medical Association over 17,000 menstrual hygiene items are needed in a user's lifetime amounting to a cost of around 2,000 dollars. While sales tax policy varies across jurisdictions, these products were typically taxed at the same rate as non-essential goods, such as in the United States, while other countries, such as the United Kingdom and Ireland, reduced or eliminated their general consumption tax on sanitary products. When asked about equivalent exemptions for men, proponents argue that no male products, condoms included, are comparable to feminine hygiene products, since menstruation is biological and "feminine hygiene is not a choice". However, others argue that other basic necessities such as toilet paper are still taxed in many countries, for example in the UK at 20%. As the vast majority of consumers of feminine hygiene products are women, the increased cost has been criticized as being discriminatory against women. The tampon tax is not a special tax levied directly on feminine hygiene products.Since about 2004, many countries have abolished or reduced sales taxes for tampons and pads, including Kenya, Canada, India, Colombia, Australia, Germany, and Rwanda.
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Tampon tax
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Tax law by jurisdiction
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Below are examples of countries that have or used to have a tampon tax (ordered by most recent changes to the country's tax system first): Belize will eliminate the General Sales Tax on feminine hygiene products on April 1, 2023. They will also no longer be subject to importation duties.
The tampon tax was abolished in Britain on 1 January 2021, following Britain's departure from the EU, meaning there is now a zero rate of VAT applying to women's sanitary products.
Rwanda removed their VAT on all sanitary products on 10 December 2019. The change was made in response to school absence and dropouts caused by 18% of Rwandan women and girls being unable to attend school or work due to not being able to afford feminine hygiene products.
Australia repealed the 10% tax on tampons and pads on 1 January 2019 after an 18-year campaign, after all states and territories agreed to make sanitary products explicitly exempt from the GST.
In Colombia, on 14 November 2018, the Constitutional Court unanimously ruled to strike down a 5 per cent tax on tampons and pads on gender equality grounds.
India eliminated its 12% tax on feminine hygiene products in 2018. This was after a year of lobbying by advocacy groups and celebrities. Actor Akshay Kumar featured as the lead male actor in Pad Man and raised awareness about the taboo on menstruation.
Mauritius eradicated its tampon tax in 2017 following a popular online petition initiated and led by gender consultant and feminist Trisha Gukhool.
Canada removed its tampon tax in mid-2015 following an online petition signed by thousands.
In 2004, Kenya was the first country to abolish sales tax for menstrual products.
European Union European Union member states can decide whether to continue to apply VAT to menstrual hygiene products, as EU rules preventing the creation of new VAT exemptions have been relaxed.
Ireland levies no value-added tax on tampons, panty liners, and sanitary towels. Ireland is the only EU country to have a zero tax rate on sanitary goods. The rate predates legislation restricting zero-rating (a grandfather clause).
In Germany, the amount of tax on sanitary items was cut from 19% (the basic rate) to 7% (the reduced rate) as of 1 January 2020. This is said to be a step toward a tax system that does not discriminate against women.
Other European countries France, Spain, Portugal, and the Netherlands either plan to, or have already, slashed their taxes in recent years.
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Tampon tax
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Tax law by jurisdiction
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United Kingdom There is a zero rate of VAT applying to women's sanitary products in the UK. The United Kingdom had levied a value-added tax on sanitary products since it joined the European Economic Community in 1973. This rate was reduced to 5% specifically for sanitary products in 2000 with lobbying from Member of Parliament Dawn Primarolo saying that this reduction was "about fairness, and doing what we can to lower the cost of a necessity." This is the lowest rate possible under the European Union's value added tax law, which as of 2016 does not allow a reduction to zero rates. The only goods that can be zero rated are those with historic zero rates that have been applied continually since before 1991. The UK Independence Party raised the issue in the 2015 general election with promised to withdraw from the European Union and allow the zero rate. Prime Minister David Cameron commented, when prompted, that the tampon tax campaign was "long-standing" and a complicated issue within the European Union. In England, one in ten women between 14 and 21 cannot afford menstrual management products.Laura Coryton led a "Stop taxing periods, period" campaign with an online petition to have the European Union remove the value-added tax for sanitary products. George Osborne mentioned the petition by name in his 2015 Autumn Statement pledge to end the tampon tax at the European Union level. The petition platform's CEO cited the campaign as an example of successful clicktivism, with over 320,000 signatures. In March 2016, Parliament created legislation to eliminate the tampon VAT, following a budget amendment by opposition Labour MP Paula Sherriff. It was expected to go into effect by April 2018 but did not do so; several British women protested for it publicly while displaying blood stains from their periods. On 3 October 2018, new EU VAT rules were put forward by the European Parliament which will allow EU countries to stop taxing sanitary products, but these will not come into effect until 2022. The UK left the EU in January 2020, and following the end of the transition period (at the beginning of 2021) the tampon tax was abolished in the UK, meaning there is now a zero rate of VAT applying to women's sanitary products. Research published by Tax Policy Associates in November 2022 suggested that savings resulting from the abolition of the tax had been retained by retailers, rather than passed onto women.
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Tampon tax
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Tax law by jurisdiction
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Scotland In July 2017, a pilot programme began in Scotland to have free sanitary products available at schools and food banks for women who cannot afford them. The pilot scheme was launched for six months in Aberdeen, with £42,500 of funding from the devolved Scottish Government in order to address the growing scandal of "period poverty". It was believed 1,000 girls would benefit from the scheme, as there were reports of teenage girls using tissues, toilet roll, torn T-shirts, and even newspaper as makeshift sanitary products, with some girls even skipping school altogether. It was decided to launch the scheme to improve attainment and school attendance, as well as improve confidence amongst teenage girls during their period; Scotland is believed to be the first country in the world to give out free sanitary products as part of a government-sponsored initiative. Further to this half-year pilot programme, Scotland's opposition Labour Party stated their intention to introduce a bill to make this permanent.
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Tampon tax
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Tax law by jurisdiction
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A study by the WHO and UNICEF showed that one out of five women in Scotland have been forced to improvise with items including toilet paper and old clothes because of the high cost of commercial products.
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Tampon tax
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Tax law by jurisdiction
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The Scottish government in 2019 began providing free sanitary products for poorer students at schools, with hopes that this would be rolled out across the entire nation.A bill to make period products available for free to everyone who needs them received preliminary approval in the Scottish Parliament in February 2020 and Members for the Scottish Parliament (MSPs) approved The Period Products (Free Provision) (Scotland) Act on Tuesday 24 November 2020. Local authorities in Scotland now have a legal duty to ensure that tampons and sanitary pads are available freely to "anyone who needs them". The bill was introduced by Labour MSP Monica Lennon who began campaigning to end period poverty in 2016. She stated that "Periods don't stop for pandemics and the work to improve access to essential tampons, pads and reusables has never been more important". The measure requires the provision of free period products in schools, colleges, and universities, as well as football clubs, restaurants, pubs, and public concert halls.The act will impose a legal duty on the local authorities to make period products available free of cost. With this act Scotland became the first country in the world to provide universal access to free period products.
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Tampon tax
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Tax law by jurisdiction
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United States Menstrual hygiene products are considered by many states within the United States as "tangible individual property" resulting in additional sales tax. This additional tax increases the overall price and further limits accessibility to menstrual hygiene products to lower-income women. These products are classified as medical devices but are not eligible for purchase through government funded assistance programs.In the United States, almost all states tax "tangible individual property" but exempt non-luxury "necessities": groceries, prescriptions, prosthetics, agriculture supplies, and sometimes clothes—the exemptions vary between states. Most states charge sales tax for women's pads and tampons. Five states do not have a state sales tax (Alaska, Delaware, Montana, New Hampshire, and Oregon), and as of June 2019, thirteen US states specifically exempted essential hygiene products: Utah, Ohio, California, Connecticut, Florida, Illinois, Maryland, Massachusetts, Minnesota, New Jersey, New York, Nevada, Pennsylvania, and Rhode Island. California repealed the tax in its 2019 state budget, but only for the two-year duration of the budget. Seven other states have introduced such legislation, most recently Nebraska, Virginia, and Arizona. In November 2021, Michigan ended its tampon tax.Many federal assistance programs such as SNAP (Supplemental Nutrition Assistance Program) and WIC (Women, Infants and Children) do not allow the use of those funds for products such as pads or tampons despite the products' classification as medical devices. The IRS does not classify female products as medical devices, thus blocking women from buying them with pre-tax dollars in both flexible spending accounts and health savings accounts.Recently, there is a movement to ensure access to the basic necessity of menstrual products for women.
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Tampon tax
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Tax law by jurisdiction
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The movement of menstrual equity has been gaining traction in recent years. This movement is based on the central tenet that period products should be affordable and accessible to women who menstruate. The movement aims to reduce the stigma around menstruation that has prevented legislative action toward achieving menstrual equity and reproductive education. Significant barriers to menstrual equity are the costs that affect women in shelters, low-income women and their daughters, LGBTQ people with uteruses, and those facing housing insecurity.In 2019, House representative Grace Meng introduced the Menstrual Equity for All bill. The bill would ensure menstrual products are free and un-rationed in schools, jails, shelters, and in all public federal buildings with federal funds. This bill proposes that menstrual products are covered under Medicaid to limit financial barriers for low-income women. The bill would also mandate large employers to free period products to employees. Since being introduced in the House, the bill is under review by the appropriate subcommittee.There have been some changes to the tampon taxes, but most of these changes are at the state or city level. On a smaller scale, individual cities have also changed their laws in favor of eliminating the tampon tax (e.g. Denver, Colorado). Maine eliminated the tax in 2022.
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California California Assemblywoman Cristina Garcia reported that California women each pay roughly US$7 per month over 40 years, constituting US$20 million in annual taxes. Garcia and Ling Ling Chang proposed a bill to remove the tampon tax in early 2016. At this time, only a handful of the country's states exempted tampons, and several others had no state sales tax. Garcia held that women were taxed "for being women" and bore an economic burden for having no other choice but to buy these products. Garcia and Chang added that the tax was "regulatory discrimination" that disproportionately affected poor women and women of color, and that it likely persisted due to social taboos against discussing menstruation. Both houses of the California State Legislature voted to exempt tampons from taxation in June 2016, but the bill was vetoed by the state's governor, Jerry Brown, three months later.California Governor Jerry Brown vetoed AB-1561 due to the potential loss of money in taxing feminine hygiene products. In response, Cristina Garcia co-authored AB-0479: Common Cents Tax Reform Act with Lorena Gonzalez Fletcher, which is a new measure outlining a solution to offset the feminine product and diaper tax exemption by increasing the tax on hard liquor. This bill was ultimately gutted and amended with provisions on workers' compensation.In 2017, California State Legislature passed AB 10 (Ch. 687) requiring public middle schools and high schools where at least 40% of students meet the federal poverty level to stock half of the restrooms with free tampons and sanitary napkins. The law was passed in an effort to eliminate the cost burden and keep low-income students in schools during their menstrual cycle.Companies involved in supplying the necessary feminine hygiene products (tampons and pads) for complete menstrual care in the restrooms of schools include WAXIE and Hospeco. They also supply various options for menstrual product dispensers that have a time delay mechanism to prevent products from being overused and/or abused.In June 2019, menstrual products were exempted from the sales tax in the state budget, but only for the two-year duration of the budget.In July 2021, California passed AB 150, making the menstrual-product tax exemption permanent.In September 2021, California passed AB367, requiring public schools grades 6–12, California State University and community college districts, as well as encouraging the Regents of the University of California and private institutions of higher learning to provide free menstrual products.
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Tampon tax
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Tax law by jurisdiction
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New York In July 2016, New York State exempted feminine hygiene products from taxation, reducing the state's tax revenue by an estimated US$10 million annually. In the court case of the "Tampon Tax", attorney Zoe Salzman defended the movement of repealing the taxes on feminine menstrual products. Part of the case was also a plea for refunding the women for all of the taxes that they had to pay on feminine menstrual products in the past. Ultimately the case ruled to repeal the taxes on feminine menstrual products, but not to refund the women of New York the previous taxes. Connecticut and Illinois also removed their tax in 2016, with Florida following suit in 2017.
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Tampon tax
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Tax law by jurisdiction
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New Jersey A 2018 empirical study on New Jersey's 2005 tax break on menstrual products found that "repealing tampon taxes removes an unequal tax burden and could make menstrual hygiene products more accessible for low-income consumers". The study utilized data from more than 16,000 purchases in 2004–2006 made in New Jersey, Delaware, Connecticut, Maryland, and Pennsylvania, using these latter nearby states as the control group. Through a differences-in-differences approach, they found that after the repeal, consumer prices on menstrual products decreased by 7.3%, relative to the control states. This was greater than the 6.9% sales tax, suggesting that the consumers benefitted from the tax break. Upon further analysis, the study also found that the decrease in consumer prices was greater for low-income consumers than high-income consumers (3.9% decrease versus 12.4% decrease). This suggests that low-income consumers received the most benefit from the tax break, while high-income consumers shared the benefit with producers of menstrual products.
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Tampon tax
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Tax law by jurisdiction
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Washington On July 1, 2020, Washington became the 20th state to remove tax from menstrual products.
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Tampon tax
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Tax law by jurisdiction
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Michigan On November 5, 2021, Michigan Governor Gretchen Whitmer signed into law bill SB 153 repealing the tax on feminine hygiene products. The bill went into effect 90 days later on February 3, 2022 Other states Many states that have tampon taxes have tried to repeal or eliminate the tax via legislation and have been denied. US states such as Tennessee, Arizona, and Virginia have introduced legislation. In Utah, Representative Susan Duckworth introduced a bill that would have exempted menstrual hygiene products from sales tax, titled "Hygiene Tax Act". Products exempted included such items as tampons and disposable diapers. Legal scholars point out that when the bill was sent to the Utah taxation committee to be voted on, eight of the eleven men voted against the bill. In November 2019, during a “special legislative session” and a Governor's signature, Utah became the thirteenth US state to abolish the tampon tax. Effective from January 1, 2020.In November 2019, Ohio became the 12th US state to repeal the pink or tampon tax. Both Representatives Greta Johnson and Brigid Kelly introduced the bills for years and finally became law in November 2019 – that would exempt feminine menstrual products from the state's sales tax. Legal scholars note that Ohio women still have to pay around four million dollars each year due to taxes on these items as they are not exempt from local taxes.In Tennessee, the same bill was sent to the Senate and House to reduce the 7% sales tax on feminine products, defined as "any product to be used by women with respect to menstruation ... [including] tampons, pads, liners, [and] cups". Both the Senate and the House did not pass the bill.In Virginia, Delegate Mark Keam introduced House Bill 952. The bill wanted to exempt the same products as Ohio and Utah from the 5.3% sales tax. Like the other two states, the bill was not passed.
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Tampon tax
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Tax law by jurisdiction
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Kenya In 2004, Kenya became the first country to exempt menstrual products from Value Added Tax. In 2011, Kenya exempted imported menstrual products from excise tax. In 2016, Kenya exempted the raw materials used for the manufacture of menstrual products from the 16% value added tax (VAT) and 25% excise tax.The government also allocated Ksh 240M to provision of free sanitary pads to girls in public governmental schools through the National Sanitary Towel Programme. This increased to Ksh 400M in 2015. However, this funding declined to 260M in 2022/2023 budget.In 2016, the Kenyan parliament introduced an amendment to the Basic Education Act which guaranteed the provision of free, sufficient and quality sanitary towels to every girl child registered and enrolled in a public basic education institution who has reached puberty and the provision of a safe and environmentally sound mechanism for disposal of the sanitary towels. These began to be distributed in 2018. The government established a Menstrual Hygiene Management Policy in 2019.
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Tampon tax
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Tax law by jurisdiction
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Canada In January 2015, the Canadian government recognised sanitary products as an essential item, ending the GST tax on all sanitary products. The Canadian government is currently debating whether to make menstrual products free in the workplace. The Government of Canada has published a Notice of Intent to the Canadian Gazette seeking feedback on providing free products in federally regulated workplaces; stakeholders and Canadians were able to feedback until July 2, 2019. Providing free menstrual products in workplaces is expected to bring better health and workplace productivity and reduced stigma around the conversation of menstruation. Under Part II of the Canada labour Code, employers are already required to provide toilet paper, soap, warm water, and a way to dry hands. Women or gender non-conforming persons who require menstrual products make up 40% of the federal workforce, and the financial burden of sanitary products rests entirely on them, burdening or severely negatively impacting those who need them, adding required sanitation products will allow for greater equality in the workplace and more opportunity for people with lower income.On May 28, 2015, the Canadian Federal Government voted in favour of lifting the tampon tax federally. The tax was ultimately repealed July 1, 2015. This was inspired by an online petition organized by Canadian Menstruators, an online advocacy group, which thousands of Canadians signed and presented to the Federal Government of Canada in Ottawa.Critics have pointed out that sanitary products are still taxed under tariffs under Canadian tariff laws.
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Tampon tax
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Tax law by jurisdiction
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China In China, menstrual products are subject to a 13% sales tax, the same as for most consumer items.
Indian Population and Menstruation With a population of 355 million, India has approximately 88% of women who are unable to acquire safe menstrual products because of a lack of capital access. The menstrual products aren't thought to be essential, therefore overpriced, and out of reach for over 70% of Indian women who menstruate.
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Tampon tax
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Activism
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Supporters of the exemption of said taxes are calling their efforts "menstrual equity", explaining it as a social movement that strives for feminine products like tampons to be considered necessities. Activists are often led by members of the government. At the beginning of 2016, councilwoman Julissa Ferreras-Copeland led a movement with a tampon tax pilot project ultimately providing free pads and tampons at a local high school in Queens, New York. Ferreras-Copeland's effort has now been expanded into 25 different schools around New York City. Other democrats including Ydanis Rodriguez and council speaker Melissa Mark-Viverito are advocating for state legislature to stop taxing sanitary products.
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Tampon tax
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Activism
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Free the Tampon, an advocate for free menstrual products estimates that it would cost less than $5 a year per user to provide tampons and pads in restrooms at schools and businesses.Activists with United for Access organized a petition and march to put pressure on the US Department of Education to eradicate period poverty in the US. They called on the government to treat period products as health necessities, support policies that protect students who menstruate, and fund period products in school bathrooms. The campaign was built in partnership with the period poverty-focused nonprofit founded by social entrepreneur, Nadya Okamoto. Okamoto is also the author of the book, Period Power: a Manifesto for the Menstrual Movement, which focuses heavily on advocating against the "tampon tax." When Okamoto was 21-years-old, she led her organization to host the first-ever National Period Day on October 19, 2019, which focused on pushing legislators to eliminate the "tampon tax." On National Period Day 2019, the organization supported local organizers to host 60 rallies in all 50 states.Slovakia levies a 20% tax on sanitary products—the basic goods rate. A Slovakian film director commented that there are no plans to change the law and that east Europe missed elements of feminist change while living under communist government.Other campaigns have emerged such as #Freeperiods encouraging state policies to provide menstrual products. #Freeperiods is a campaign started by Amika George who started a petition aimed at encouraging the UK government to provide low-income families with subsidised menstrual products. This campaign since then has grown exponentially. The Free periods initiative has recently paired up with The Red Box Project, which is a community-based initiative that provides free menstrual products and underwear to young women who struggle financially. The Red Box Projects notes the importance of their initiative as according to #Freeperiods one out of 10 girls can't afford to purchase menstrual products and over 137,000 girls have missed school due to period poverty.Within the Global North, tampon activism has been strong and well-supported. Countries are moving forward and either removing tampon taxes or providing free menstrual products. In 2018 the Scottish Government moved forward and became the first country to provide free menstrual products for students at schools and universities. Additionally, other countries have moved forward in implementing policies around providing sanitary products and abolishing taxes on menstrual products. Kenya and Uganda moved forward and removed taxes on these products. Furthermore, the Kenyan government also provides funding to schools that provide pads.
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Flash mob
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Flash mob
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A flash mob (or flashmob) is a group of people who assemble suddenly in a public place, perform for a brief time, then quickly disperse, often for the purposes of entertainment, satire, and artistic expression. Flash mobs may be organized via telecommunications, social media, or viral emails.The term, coined in 2003, is generally not applied to events and performances organized for the purposes of politics (such as protests), commercial advertisement, publicity stunts that involve public relation firms, or paid professionals. In these cases of a planned purpose for the social activity in question, the term smart mobs is often applied instead.
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Flash mob
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Flash mob
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The term "flash rob" or "flash mob robberies", a reference to the way flash mobs assemble, has been used to describe a number of robberies and assaults perpetrated suddenly by groups of teenage youth. Bill Wasik, originator of the first flash mobs, and a number of other commentators have questioned or objected to the usage of "flash mob" to describe criminal acts. Flash mob has also been featured in some Hollywood movie series, such as Step Up.
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Flash mob
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History
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First flash mob The first flash mobs were created in Manhattan in 2003, by Bill Wasik, senior editor of Harper's Magazine. The first attempt was unsuccessful after the targeted retail store was tipped off about the plan for people to gather. Wasik avoided such problems during the first successful flash mob, which occurred on June 17, 2003, at Macy's department store, by sending participants to preliminary staging areas—in four Manhattan bars—where they received further instructions about the ultimate event and location just before the event began.More than 130 people converged upon the ninth-floor rug department of the store, gathering around an expensive rug. Anyone approached by a sales assistant was advised to say that the gatherers lived together in a warehouse on the outskirts of New York, that they were shopping for a "love rug", and that they made all their purchase decisions as a group. Subsequently, 200 people flooded the lobby and mezzanine of the Hyatt hotel in synchronized applause for about 15 seconds, and a shoe boutique in SoHo was invaded by participants pretending to be tourists on a bus trip.Wasik claimed that he created flash mobs as a social experiment designed to poke fun at hipsters and to highlight the cultural atmosphere of conformity and of wanting to be an insider or part of "the next big thing". The Vancouver Sun wrote, "It may have backfired on him ... [Wasik] may instead have ended up giving conformity a vehicle that allowed it to appear nonconforming." In another interview he said "the mobs started as a kind of playful social experiment meant to encourage spontaneity and big gatherings to temporarily take over commercial and public areas simply to show that they could".
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Flash mob
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History
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Precedents and precursors In 19th-century Tasmania, the term flash mob was used to describe a subculture consisting of female prisoners, based on the term flash language for the jargon that these women used. The 19th-century Australian term flash mob referred to a segment of society, not an event, and showed no other similarities to the modern term flash mob or the events it describes.In 1973, the story "Flash Crowd" by Larry Niven described a concept similar to flash mobs. With the invention of popular and very inexpensive teleportation, an argument at a shopping mall—which happens to be covered by a news crew—quickly swells into a riot. In the story, broadcast coverage attracts the attention of other people, who use the widely available technology of the teleportation booth to swarm first that event—thus intensifying the riot—and then other events as they happen. Commenting on the social impact of such mobs, one character (articulating the police view) says, "We call them flash crowds, and we watch for them." In related short stories, they are named as a prime location for illegal activities (such as pickpocketing and looting) to take place. Lev Grossman suggests that the story title is a source of the term "flash mob".
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Flash mob
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History
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Flash mobs began as a form of performance art. While they started as an apolitical act, flash mobs may share superficial similarities to political demonstrations. In the 1960s, groups such as the Yippies used street theatre to expose the public to political issues. Flash mobs can be seen as a specialized form of smart mob, a term and concept proposed by author Howard Rheingold in his 2002 book Smart Mobs: The Next Social Revolution.
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Flash mob
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Use of the term
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The first documented use of the term flash mob as it is understood today was in 2003 in a blog entry posted in the aftermath of Wasik's event. The term was inspired by the earlier term smart mob.Flash mob was added to the 11th edition of the Concise Oxford English Dictionary on July 8, 2004, where it noted it as an "unusual and pointless act" separating it from other forms of smart mobs such as types of performance, protests, and other gatherings. Also recognized noun derivatives are flash mobber and flash mobbing. Webster's New Millennium Dictionary of English defines flash mob as "a group of people who organize on the Internet and then quickly assemble in a public place, do something bizarre, and disperse." This definition is consistent with the original use of the term; however, both news media and promoters have subsequently used the term to refer to any form of smart mob, including political protests; a collaborative Internet denial of service attack; a collaborative supercomputing demonstration; and promotional appearances by pop musicians. The press has also used the term flash mob to refer to a practice in China where groups of shoppers arrange online to meet at a store in order to drive a collective bargain.
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Flash mob
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Legality
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The city of Brunswick, Germany, has stopped flash mobs by strictly enforcing the already existing law of requiring a permit to use any public space for an event. In the United Kingdom, a number of flash mobs have been stopped over concerns for public health and safety. The British Transport Police have urged flash mob organizers to "refrain from holding such events at railway stations".
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Flash mob
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Crime
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Referred to as flash robs, flash mob robberies, or flash robberies by the media, crimes organized by teenage youth using social media rose to international notoriety beginning in 2011. The National Retail Federation does not classify these crimes as "flash mobs" but rather "multiple offender crimes" that utilize "flash mob tactics". In a report, the NRF noted, "multiple offender crimes tend to involve groups or gangs of juveniles who already know each other, which does not earn them the term 'flash mob'." Mark Leary, a professor of psychology and neuroscience at Duke University, said that most "flash mob thuggery" involves crimes of violence that are otherwise ordinary, but are perpetrated suddenly by large, organized groups of people: "What social media adds is the ability to recruit such a large group of people, that individuals who would not rob a store or riot on their own feel freer to misbehave without being identified." It's hard for me to believe that these kids saw some YouTube video of people Christmas caroling in a food court, and said, 'Hey, we should do that, except as a robbery!' More likely, they stumbled on the simple realization (like I did back in 2003, but like lots of other people had before and have since) that one consequence of all this technology is that you can coordinate a ton of people to show up in the same place at the same time.
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Flash mob
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Crime
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These kids are taking part in what's basically a meme. They heard about it from friends, and probably saw it on YouTube, and now they're getting their chance to participate in it themselves.
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Flash mob
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Crime
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HuffPost raised the question asking if "the media was responsible for stirring things up", and added that in some cases the local authorities did not confirm the use of social media making the "use of the term flash mob questionable". Amanda Walgrove wrote that criminals involved in such activities don't refer to themselves as "flash mobs", but that this use of the term is nonetheless appropriate. Dr. Linda Kiltz drew similar parallels between flash robs and the Occupy Movement stating, "As the use of social media increases, the potential for more flash mobs that are used for political protest and for criminal purposes is likely to increase.".
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Urban heat island
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Urban heat island
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An urban heat island (UHI) is an urban area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak. UHI is most noticeable during the summer and winter. The main cause of the UHI effect is from the modification of land surfaces. A study has shown that heat islands can be affected by proximity to different types of land cover, so that proximity to barren land causes urban land to become hotter and proximity to vegetation makes it cooler. Waste heat generated by energy usage is a secondary contributor. As a population center grows, it tends to expand its area and increase its average temperature. The term heat island is also used; the term can be used to refer to any area that is relatively hotter than the surrounding, but generally refers to human-disturbed areas.Monthly rainfall is greater downwind of cities, partially due to the UHI. Increases in heat within urban centers increases the length of growing seasons and decreases the occurrence of weak tornadoes. The UHI decreases air quality by increasing the production of pollutants such as ozone, and decreases water quality as warmer waters flow into area streams and put stress on their ecosystems.
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Urban heat island
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Urban heat island
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Not all cities have a distinct urban heat island, and the heat island characteristics depend strongly on the background climate of the area in which the city is located. Effects within a city can vary significantly depending on local environmental conditions. Heat can be reduced by tree cover and green space, which act as sources of shade and promote evaporative cooling.
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Urban heat island
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Urban heat island
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Other options include green roofs, passive daytime radiative cooling applications, and the use of lighter-colored surfaces and less absorptive building materials in urban areas, to reflect more sunlight and absorb less heat.Climate change is not the cause of urban heat islands but it is causing more frequent and more intense heat waves which in turn amplify the urban heat island effect in cities.: 993 Compact, dense urban development may increase the urban heat island effect, leading to higher temperatures and increased exposure.
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Urban heat island
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Description
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Definition A definition of urban heat island is: "The relative warmth of a city compared with surrounding rural areas.": 2926 This relative warmth is caused by "heat trapping due to land use, the configuration and design of the built environment, including street layout and building size, the heat-absorbing properties of urban building materials, reduced ventilation, reduced greenery and water features, and domestic and industrial heat emissions generated directly from human activities".: 2926 Diurnal variability For most cities, the difference in temperature between the urban and surrounding rural area is largest at night. While temperature difference is significant all year round, the difference is generally bigger in winter. The typical temperature difference is several degrees between the city and surrounding areas. The difference in temperature between an inner city and its surrounding suburbs is frequently mentioned in weather reports, as in "68 °F (20 °C) downtown, 64 °F (18 °C) in the suburbs". In the United States, the difference during the day is between 0.6–3.9 °C (1–7 °F), while the difference during the night is 1.1–2.8 °C (2–5 °F). The difference is larger for bigger cities and areas with a high air humidity.Though the warmer air temperature within the UHI is generally most apparent at night, urban heat islands exhibit significant and somewhat paradoxical diurnal behavior. The air temperature difference between the UHI and the surrounding environment is large at night and small during the day.Throughout the daytime, particularly when the skies are cloudless, urban surfaces are warmed by the absorption of solar radiation. Surfaces in the urban areas tend to warm faster than those of the surrounding rural areas. By virtue of their high heat capacities, urban surfaces act as a giant reservoir of heat energy. For example, concrete can hold roughly 2,000 times as much heat as an equivalent volume of air. As a result, the large daytime surface temperature within the UHI is easily seen via thermal remote sensing. As is often the case with daytime heating, this warming also has the effect of generating convective winds within the urban boundary layer. It is theorized that, due to the atmospheric mixing that results, the air temperature perturbation within the UHI is generally minimal or nonexistent during the day, though the surface temperatures can reach extremely high levels.At night, the situation reverses. The absence of solar heating leads to the decrease of atmospheric convection and the stabilization of urban boundary layer. If enough stabilization occurs, an inversion layer is formed. This traps urban air near the surface, and keeping surface air warm from the still-warm urban surfaces, resulting in warmer nighttime air temperatures within the UHI. Other than the heat retention properties of urban areas, the nighttime maximum in urban canyons could also be due to the blocking of "sky view" during cooling: surfaces lose heat at night principally by radiation to the comparatively cool sky, and this is blocked by the buildings in an urban area. Radiative cooling is more dominant when wind speed is low and the sky is cloudless, and indeed the UHI is found to be largest at night in these conditions.
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Urban heat island
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Description
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Seasonal variability The urban heat island temperature difference is not only usually larger at night than during the day, but also larger in winter than in summer. This is especially true in areas where snow is common, as cities tend to hold snow for shorter periods of time than surrounding rural areas (this is due to the higher insulation capacity of cities, as well as human activities such as plowing). This decreases the albedo of the city and thereby magnifies the heating effect. Higher wind speeds in rural areas, particularly in winter, can also function to make them cooler than urban areas. Regions with distinct wet and dry seasons will exhibit a larger urban heat island effect during the dry season.
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Urban heat island
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Description
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Models and simulations If a city or town has a good system of taking weather observations the UHI can be measured directly. An alternative is to use a complex simulation of the location to calculate the UHI, or to use an approximate empirical method. Such models allow the UHI to be included in estimates of future temperatures rises within cities due to climate change.
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Urban heat island
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Description
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Leonard O. Myrup published the first comprehensive numerical treatment to predict the effects of the urban heat island (UHI) in 1969. The heat island effect was found to be the net result of several competing physical processes. In general, reduced evaporation in the city center and the thermal properties of the city building and paving materials are the dominant parameters. Modern simulation environments include ENVI-met, which simulates all interactions between building and ground surfaces, plants and ambient air.
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Urban heat island
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Causes
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There are several causes of an urban heat island (UHI); for example, dark surfaces absorb significantly more solar radiation, which causes urban concentrations of roads and buildings to heat more than suburban and rural areas during the day; materials commonly used in urban areas for pavement and roofs, such as concrete and asphalt, have significantly different thermal bulk properties (including heat capacity and thermal conductivity) and surface radiative properties (albedo and emissivity) than the surrounding rural areas. This causes a change in the energy budget of the urban area, often leading to higher temperatures than surrounding rural areas.Pavements, parking lots, roads or, more generally speaking transport infrastructure, contribute significantly to the urban heat island effect. For example pavement infrastructure is a main contributor to urban heat during summer afternoons in Phoenix, United States.Another major reason is the lack of evapotranspiration (for example, through lack of vegetation) in urban areas. The U.S. Forest Service found in 2018 that cities in the United States are losing 36 million trees each year. With a decreased amount of vegetation, cities also lose the shade and evaporative cooling effect of trees.Other causes of a UHI are due to geometric effects. The tall buildings within many urban areas provide multiple surfaces for the reflection and absorption of sunlight, increasing the efficiency with which urban areas are heated. This is called the "urban canyon effect". Another effect of buildings is the blocking of wind, which also inhibits cooling by convection and prevents pollutants from dissipating. Waste heat from automobiles, air conditioning, industry, and other sources also contributes to the UHI.High levels of pollution in urban areas can also increase the UHI, as many forms of pollution change the radiative properties of the atmosphere. UHI not only raises urban temperatures but also increases ozone concentrations because ozone is a greenhouse gas whose formation will accelerate with the increase of temperature.
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Urban heat island
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Causes
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Climate change as an amplifier Climate change is not a cause but an amplifier of the urban heat island effect. The IPCC Sixth Assessment Report from 2022 summarized the available research accordingly: "Climate change increases heat stress risks in cities [...] and amplifies the urban heat island across Asian cities at 1.5°C and 2°C warming levels, both substantially larger than under present climates [...].": 66 The report goes on to say: "In a warming world, increasing air temperature makes the urban heat island effect in cities worse. One key risk is heatwaves in cities that are likely to affect half of the future global urban population, with negative impacts on human health and economic productivity.": 993 There are unhelpful interactions between heat and built infrastructure: These interactions increase the risk of heat stress for people living in cities.: 993
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Urban heat island
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Impacts
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On weather and climate Aside from the effect on temperature, UHIs can produce secondary effects on local meteorology, including the altering of local wind patterns, the development of clouds and fog, the humidity, and the rates of precipitation. The extra heat provided by the UHI leads to greater upward motion, which can induce additional shower and thunderstorm activity. In addition, the UHI creates during the day a local low pressure area where relatively moist air from its rural surroundings converges, possibly leading to more favorable conditions for cloud formation. Rainfall rates downwind of cities are increased between 48% and 116%. Partly as a result of this warming, monthly rainfall is about 28% greater between 20 miles (32 km) to 40 miles (64 km) downwind of cities, compared with upwind. Some cities show a total precipitation increase of 51%.One study concluded that cities change the climate in area 2–4 times larger than their own area. One 1999 comparison between urban and rural areas proposed that urban heat island effects have little influence on global mean temperature trends. Others suggested that urban heat islands affect global climate by impacting the jet stream.
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Urban heat island
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Impacts
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On human health UHIs have the potential to directly influence the health and welfare of urban residents. As UHIs are characterized by increased temperature, they can potentially increase the magnitude and duration of heat waves within cities. The number of individuals exposed to extreme temperatures is increased by the UHI-induced warming. The nighttime effect of UHIs can be particularly harmful during a heat wave, as it deprives urban residents of the cool relief found in rural areas during the night.Increased temperatures have been reported to cause heat illnesses, such as heat stroke, heat exhaustion, heat syncope, and heat cramps.High UHI intensity correlates with increased concentrations of air pollutants that gathered at night, which can affect the next day's air quality. These pollutants include volatile organic compounds, carbon monoxide, nitrogen oxides, and particulate matter. The production of these pollutants combined with the higher temperatures in UHIs can quicken the production of ozone. Ozone at surface level is considered to be a harmful pollutant. Studies suggest that increased temperatures in UHIs can increase polluted days but also note that other factors (e.g. air pressure, cloud cover, wind speed) can also have an effect on pollution.Studies from Hong Kong have found that areas of the city with poorer outdoor urban air ventilation tended to have stronger urban heat island effects and had significantly higher all-cause mortality compared to areas with better ventilation.
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Urban heat island
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Impacts
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On water bodies and aquatic organisms UHIs also impair water quality. Hot pavement and rooftop surfaces transfer their excess heat to stormwater, which then drains into storm sewers and raises water temperatures as it is released into streams, rivers, ponds, and lakes. Additionally, increased urban water body temperatures lead to a decrease in diversity in the water. For example, in August 2001, rains over Cedar Rapids, Iowa led to a 10.5C (18.9F) rise in the nearby stream within one hour, resulting in a fish kill which affected an estimated 188 fish. Since the temperature of the rain was comparatively cool, it could be attributed to the hot pavement of the city. Similar events have been documented across the American Midwest, as well as Oregon and California. Rapid temperature changes can be stressful to aquatic ecosystems.With the temperature of the nearby buildings sometimes reaching a difference of over 50 °F (28 °C) from the near-surface air temperature, precipitation will warm rapidly, causing run-off into nearby streams, lakes and rivers (or other bodies of water) to provide excessive thermal pollution. The increase in thermal pollution has the potential to increase water temperature by 20 to 30 °F (11 to 17 °C). This increase will cause the fish species inhabiting the body of water to undergo thermal stress and shock due to the rapid change in temperature of their habitat.Permeable pavements may reduce these effects by percolating water through the pavement into subsurface storage areas where it can be dissipated through absorption and evaporation.
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Urban heat island
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Impacts
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On animals Species that are good at colonizing can utilize conditions provided by urban heat islands to thrive in regions outside of their normal range. Examples of this include the grey-headed flying fox (Pteropus poliocephalus) and the common house gecko (Hemidactylus frenatus). Grey-headed flying foxes, found in Melbourne, Australia, colonized urban habitats following the increase in temperatures there. Increased temperatures, causing warmer winter conditions, made the city more similar in climate to the more northerly wildland habitat of the species.
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Urban heat island
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Impacts
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With temperate climates, urban heat islands will extend the growing season, therefore altering breeding strategies of inhabiting species. This can be best observed in the effects that urban heat islands have on water temperature (see effects on water bodies). Urban heat islands caused by cities have altered the natural selection process. Selective pressures like temporal variation in food, predation and water are relaxed causing a new set of selective forces to roll out. For example, within urban habitats, insects are more abundant than in rural areas. Insects are ectotherms. This means that they depend on the temperature of the environment to control their body temperature, making the warmer climates of the city perfect for their ability to thrive. A study done in Raleigh, North Carolina conducted on Parthenolecanium quercifex (oak scales), showed that this particular species preferred warmer climates and were therefore found in higher abundance in urban habitats than on oak trees in rural habitats. Over time spent living in urban habitats, they have adapted to thrive in warmer climates than in cooler ones.
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Urban heat island
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Impacts
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On energy usage for cooling Another consequence of urban heat islands is the increased energy required for air conditioning and refrigeration in cities that are in comparatively hot climates. The heat island effect costs Los Angeles about US$ 100 million per year in energy (in the year 2000). Through the implementation of heat island reduction strategies, significant annual net energy savings have been calculated for northern locations such as Chicago, Salt Lake City, and Toronto.Every year in the U.S. 15% of energy goes towards the air conditioning of buildings in these urban heat islands. It was reported in 1998 that "the air conditioning demand has risen 10% within the last 40 years."
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Urban heat island
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Options for reducing heat island effects
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Strategies to improve urban resilience by reducing excessive heat in cities include: Planting trees in cities, white roofs and light-coloured concrete, green infrastructure (including green roofs), passive daytime radiative cooling.The temperature difference between urban areas and the surrounding suburban or rural areas can be as much as 5 °C (9.0 °F). Nearly 40 percent of that increase is due to the prevalence of dark roofs, with the remainder coming from dark-colored pavement and the declining presence of vegetation. The heat island effect can be counteracted slightly by using white or reflective materials to build houses, roofs, pavements, and roads, thus increasing the overall albedo of the city.
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Urban heat island
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Options for reducing heat island effects
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Planting trees in cities Planting trees around the city can be another way of increasing albedo and decreasing the urban heat island effect. It is recommended to plant deciduous trees because they can provide many benefits such as more shade in the summer and not blocking warmth in winter. Trees are a necessary feature in combating most of the urban heat island effect because they reduce air temperatures by 10 °F (5.6 °C), and surface temperatures by up to 20–45 °F (11–25 °C).
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Urban heat island
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Options for reducing heat island effects
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White roofs and light-coloured concrete Painting rooftops white has become a common strategy to reduce the heat island effect. In cities, there are many dark colored surfaces that absorb the heat of the sun in turn lowering the albedo of the city. White rooftops allow high solar reflectance and high solar emittance, increasing the albedo of the city or area the effect is occurring.Relative to remedying the other sources of the problem, replacing dark roofing requires the least amount of investment for the most immediate return. A cool roof made from a reflective material such as vinyl reflects at least 75 percent of the sun's rays, and emit at least 70 percent of the solar radiation absorbed by the building envelope. Asphalt built-up roofs (BUR), by comparison, reflect 6 percent to 26 percent of solar radiation.Using light-colored concrete has proven effective in reflecting up to 50% more light than asphalt and reducing ambient temperature. A low albedo value, characteristic of black asphalt, absorbs a large percentage of solar heat creating warmer near-surface temperatures. Paving with light-colored concrete, in addition to replacing asphalt with light-colored concrete, communities may be able to lower average temperatures. However, research into the interaction between reflective pavements and buildings has found that, unless the nearby buildings are fitted with reflective glass, solar radiation reflected off light-colored pavements can increase building temperatures, increasing air conditioning demands.There are specific paint formulations for daytime radiative cooling that reflect up to 98.1% of sunlight.
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Urban heat island
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Options for reducing heat island effects
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Green infrastructure Another option is to increase the amount of well-watered vegetation. These two options can be combined with the implementation of green roofs. Green roofs are excellent insulators during the warm weather months and the plants cool the surrounding environment. Air quality is improved as the plants absorb carbon dioxide with concomitant production of oxygen.Green roofs decrease the urban heat island effect. Green roofery is the practice of having vegetation on a roof; such as having trees or a garden. The plants that are on the roof increase the albedo and decreases the urban heat island effect. This method has been studied and criticized for the fact that green roofs are affected by climatic conditions, green roof variables are hard to measure, and are very complex systems.The cost efficiency of green roofs is quite high because of several reasons. For one, green roofs have over double the lifespan of a conventional roof, effectively decelerating the amount of roof replacements every year. In addition to roof-life, green roofs add stormwater management reducing fees for utilities. The cost for green roofs is more in the beginning, but over a period of time, their efficiency provides financial as well as health benefits. However, "A conventional roof is estimated to be $83.78/m2 while a green roof was estimated at $158.82/m2."Green parking lots use vegetation and surfaces other than asphalt to limit the urban heat island effect.
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Urban heat island
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Options for reducing heat island effects
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Passive daytime radiative cooling A passive daytime radiative cooling roof application can double the energy savings of a white roof, attributed to high solar reflectance and thermal emittance in the infrared window, with the highest cooling potential in hot and dry cities such as Phoenix and Las Vegas. When installed on roofs in dense urban areas, passive daytime radiative cooling panels can significantly lower outdoor surface temperatures at the pedestrian level.
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Urban heat island
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Society and culture
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History of research The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon. A description of the very first report of the UHI by Luke Howard said that the urban center of London was warmer at night than the surrounding countryside by 2.1 °C (3.7 °F).Investigations of the urban atmosphere continued throughout the nineteenth century. Between the 1920s and the 1940s, researchers in the emerging field of local climatology or microscale meteorology in Europe, Mexico, India, Japan, and the United States pursued new methods to understand the phenomenon. In 1929, Albert Peppler used the term in a German publication believed to be the first instance of an equivalent to urban heat island: städtische Wärmeinsel (which is urban heat island in German). Between 1990 and 2000, about 30 studies were published annually; by 2010, that number had increased to 100, and by 2015, it was more than 300.Leonard O. Myrup published the first comprehensive numerical treatment to predict the effects of the urban heat island (UHI) in 1969. His paper surveys UHI and criticizes then-existing theories as being excessively qualitative.
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Urban heat island
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Society and culture
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Aspects of social inequality Some studies suggest that the effects of UHIs on health may be disproportionate, since the impacts may be unevenly distributed based on a variety of factors such as age, ethnicity and socioeconomic status. This raises the possibility of health impacts from UHIs being an environmental justice issue.
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Urban heat island
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Society and culture
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There is a correlation between neighborhood income and tree canopy cover. Low-income neighborhoods tend to have significantly fewer trees than neighborhoods with higher incomes. Researchers hypothesized that less-well-off neighborhoods do not have the financial resources to plant and maintain trees. Affluent neighborhoods can afford more trees, on "both public and private property." Part of this is also that wealthier homeowners and communities can afford more land, which can be kept open as green space, whereas poorer ones are often rentals, where landowners try to maximize their profit by putting as much density as possible on their land.
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Urban heat island
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Society and culture
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Researchers have also noted that the spread of impervious surfaces is correlated with low socioeconomic status neighborhoods across various U.S. cities and states. The presence of these materials, which include concrete, tar and asphalt, serves as a predictor of "intra-urban variation in temperature".
Chief heat officers Beginning in the 2020s, a number of cities worldwide began creating Chief Heat Officer positions to organize and manage work counteracting the urban heat island effect.
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Urban heat island
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Examples
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United States Bill S.4280, introduced to the U.S. Senate in 2020, would authorize the National Integrated Heat Health Information System Interagency Committee (NIHHIS) to tackle extreme heat in the United States. Successful passage of this legislation would fund NIHHIS for five years and would instate a $100 million grant program within NIHHIS to encourage and fund urban heat reduction projects, including those using cools roofs and pavements and those improving HVAC systems. As of July 22, 2020 the bill has not moved past introduction to Congress.
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Urban heat island
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Examples
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The city of New York determined that the cooling potential per area was highest for street trees, followed by living roofs, light covered surface, and open space planting. From the standpoint of cost effectiveness, light surfaces, light roofs, and curbside planting have lower costs per temperature reduction.
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Urban heat island
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Examples
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Los Angeles A hypothetical "cool communities" program in Los Angeles has projected in 1997 that urban temperatures could be reduced by approximately 3 °C (5 °F) after planting ten million trees, reroofing five million homes, and painting one-quarter of the roads at an estimated cost of US$1 billion, giving estimated annual benefits of US$170 million from reduced air-conditioning costs and US$360 million in smog related health savings.In a case study of the Los Angeles Basin in 1998, simulations showed that even when trees are not strategically placed in these urban heat islands, they can still aid in minimization of pollutants and energy reduction. It is estimated that with this wide-scale implementation, the city of Los Angeles can annually save $100M with most of the savings coming from cool roofs, lighter colored pavement, and the planting of trees. With a citywide implementation, added benefits from the lowering smog-level would result in at least one billion dollars of saving per year.Los Angeles TreePeople is an example of how tree planting can empower a community. Tree people provides the opportunity for people to come together, build capacity, community pride and the opportunity to collaborate and network with each other.
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Urban heat island
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Examples
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Athens green space initiative Athens, the capital of Greece, has undertaken initiatives to reduce the urban heat island effect and reduce the impact of pollution from vehicles. To create green spaces that offer cooling, small unused plots of land are being reconfigured into pocket parks.
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Malpuech facial clefting syndrome
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Malpuech facial clefting syndrome
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Malpuech facial clefting syndrome, also called Malpuech syndrome or Gypsy type facial clefting syndrome, is a rare congenital syndrome. It is characterized by facial clefting (any type of cleft in the bones and tissues of the face, including a cleft lip and palate), a caudal appendage (a "human tail"), growth deficiency, intellectual and developmental disability, and abnormalities of the renal system (kidneys) and the male genitalia. Abnormalities of the heart, and other skeletal malformations may also be present. The syndrome was initially described by Georges Malpuech and associates in 1983. It is thought to be genetically related to Juberg-Hayward syndrome. Malpuech syndrome has also been considered as part of a spectrum of congenital genetic disorders associated with similar facial, urogenital and skeletal anomalies. Termed "3MC syndrome", this proposed spectrum includes Malpuech, Michels and Mingarelli-Carnevale (OSA) syndromes. Mutations in the COLLEC11 and MASP1 genes are believed to be a cause of these syndromes. The incidence of Malpuech syndrome is unknown. The pattern of inheritance is autosomal recessive, which means a defective (mutated) gene associated with the syndrome is located on an autosome, and the syndrome occurs when two copies of this defective gene are inherited.
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Malpuech facial clefting syndrome
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Signs and symptoms
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Malpuech syndrome is congenital, being apparent at birth. It is characterized by a feature known as facial clefting. Observed and noted in the initial description of the syndrome as a cleft lip and palate, facial clefting is identified by clefts in the bones, muscles and tissues of the face, including the lips and palate. The forms of cleft lip and palate typically seen with Malpuech syndrome are midline (down the middle of the lip and palate) or bilateral (affecting both sides of the mouth and palate). Facial clefting generally encompasses a wide range of severity, ranging from minor anomalies such as a bifid (split) uvula, to a cleft lip and palate, to major developmental and structural defects of the facial bones and soft tissues. Clefting of the lip and palate occurs during embryogenesis. Additional facial and ortho-dental anomalies that have been described with the syndrome include: hypertelorism (unusually wide-set eyes, sometimes reported as telecanthus), narrow palpebral fissures (the separation between the upper and lower eyelids) and ptosis (drooping) of the eyelids, frontal bossing (prominent eyebrow ridge) with synophris, highly arched eyebrows, wide nasal root and a flattened nasal tip, malar hypoplasia (underdeveloped upper cheek bone), micrognathia (an undersized lower jaw), and prominent incisors. Auditory anomalies include an enlarged ear ridge, and hearing impairment associated with congenital otitis media (or "glue ear", inflammation of the middle ear) and sensorineural hearing loss.Another feature identified with Malpuech syndrome is a caudal appendage. A caudal appendage is a congenital outgrowth stemming from the coccyx (tailbone). Present in many non-human animal species as a typical tail, this feature when seen in an infant has been described as a "human tail". This was observed by Guion-Almeida (1995) in three individuals from Brazil. The appendage on X-rays variously appeared as a prominent protrusion of the coccyx. On a physical examination, the appendage resembles a nodule-like stub of an animal tail.Deficiencies such as intellectual disability, learning disability, growth retardation and developmental delay are common. Psychiatric manifestations that have been reported with the syndrome include psychotic behavior, obsessive–compulsive disorder, loss of inhibition, hyperactivity, aggression, fear of physical contact, and compulsive actions like echolalia (repeating the words spoken by another person). Neuromuscular tics have also been noted.Urogenital abnormalities, or those affecting the urinary and reproductive systems, are common with the syndrome. Malpuech et al. (1983) and Kerstjens-Frederikse et al. (2005) reported variously in affected males a micropenis, hypospadias (a congenital mislocation of the urinary meatus), cryptorchidism (ectopic or undescended testes), bifid (split) and underdeveloped scrotum, and an obstructive urethral valve. An affected boy was also reported by Reardon et al. (2001) with left renal agenesis, an enlarged and downwardly displaced right kidney, cryptorchidism and a shawl scrotum. Other malformations that have been noted with the syndrome are omphalocele and an umbilical hernia.
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Malpuech facial clefting syndrome
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Signs and symptoms
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Congenital abnormalities of the heart have also been observed with Malpuech syndrome. From a healthy Japanese couple, Chinen and Naritomi (1995) described the sixth child who had features consistent with the disorder. This two-month-old male infant was also affected by cardiac anomalies including patent ductus arteriosus (PDA) and ventricular septal defect. The opening in the ductus arteriosus associated with PDA had been surgically repaired in the infant at 38 days of age. A number of minor skeletal aberrations were also reported in the infant, including wormian bones at the lambdoid sutures.
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Malpuech facial clefting syndrome
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Genetics
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Malpuech syndrome, as with the other disorders within the 3MC syndrome consideration, is caused by mutations in the COLLEC11 and MASP1 genes. In an investigation by Rooryck et al. (2011), eleven families affected by 3MC syndrome were studied, which resulted in the identification of these two mutations. Both genes encode proteins of the lectin complement pathway, which plays a role in the complement system of innate, or non-specific immunity in humans and other species.The COLLEC11, or CL-K1 gene is located on the short arm of chromosome 2 (2p25.3) in humans. The CL-K1 protein is a C-type lectin, and belongs to the collectin family of these proteins. Other than its role in innate immunity, the protein is thought to be involved in the development of tissues including craniofacial cartilage, the heart and kidney during embryogenesis. This function in facial development was corroborated through study of the zebrafish, where mutations in its version of CL-K1 contributed to craniofacial abnormalities (such as Craniofacial clefts) possibly associated with errors in neural crest cell migration.
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Malpuech facial clefting syndrome
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Genetics
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The MASP1, or Mannan-binding Serine Protease I gene is located on the long arm of human chromosome 3 at 3q27-q28. The protein is a type of connectin called a mannan-binding lectin, which plays a role in innate immunity by binding to pathogens such as viruses including HIV.As described by Sirmaci et al. (2010), three Turkish individuals from two consanguineous families (the children of relatives such as cousins are said to be in a consanguineous family) with various characteristics of 3MC syndrome, including facial dysmorphism and a caudal appendage, were evaluated. Investigation of homologous chromosomes through gene mapping revealed an autozygous region (a location on a chromosome where both alleles of a gene originate from a common ancestor) at chromosome 3q27 in both families. In one family, a missense mutation in MASP1 at this location resulted in the replacement of the amino acid glycine by arginine at position 687 in the gene sequence. The mutation cosegregated with the observed phenotype. In individuals from the second family, DNA sequencing of MASP1 showed a nonsense mutation that resulted in a deactivation of tryptophan at position 290 in the gene, that also cosegregated with the phenotype. Both mutations occur in a form of MASP1 known to process IGFBP5; loss of this function associated with mutation of MASP1 causes disruptions in the availability of insulin-like growth factor during craniofacial and musculoskeletal development during the embryonic period. These results indicate that mutations in MASP1 are responsible for an array of features found with malformation disorders including Malpuech syndrome.The syndrome is inherited in an autosomal recessive manner. This means the defective gene(s) responsible for the disorder (COLLEC11, MASP1) is located on an autosome (chromosomes 2 and 3 are autosomes), and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.
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Malpuech facial clefting syndrome
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Diagnosis
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It is suggested that the diagnostic criteria for Malpuech syndrome should include cleft lip and/or palate, typical associated facial features, and at least two of the following: urogenital anomalies, caudal appendage, and growth or developmental delay.
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Malpuech facial clefting syndrome
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Diagnosis
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Due to the relatively high rate of hearing impairment found with the disorder, it too may be considered in the diagnosis. Another congenital disorder, Wolf-Hirschhorn (Pitt-Rogers-Danks) syndrome, shares Malpuech features in its diagnostic criteria. Because of this lacking differentiation, karyotyping (microscopic analysis of the chromosomes of an individual) can be employed to distinguish the two. Whereas deletions in the short arm of chromosome 4 would be revealed with Wolf-Hirschhorn, a karyotype without this aberration present would favor a Malpuech syndrome diagnosis. Also, the karyotype of an individual with Malpuech syndrome alone will be normal.
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Malpuech facial clefting syndrome
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Diagnosis
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Classification Malpuech syndrome has been shown to have physical, or phenotypical similarities with several other genetic disorders. A report by Reardon et al. (2001) of a nine-year-old boy exhibiting facial, caudal and urogenital anomalies consistent with Malpuech syndrome, who also had skeletal malformites indicative of Juberg-Hayward syndrome, suggests that the two disorders may be allelic (caused by different mutations of the same gene).Along with several other disorders that have similar, or overlapping features and autosomal recessive inheritance, Malpuech syndrome has been considered to belong under the designation "3MC syndrome". Titomanlio et al. (2005) described a three-year-old female known to have Michels syndrome. In their review of the physical similarities between Michels, Malpuech and Mingarelli-Carnevale syndromes—particularly the facial appearance including instances of cleft lip and palate, and ptosis, and a similarity of congenital abdominal and urogenital anomalies—they believed the syndromes may represent a spectrum of genetic disorders rather than three individual disorders. They initially suggested this spectrum could be named 3MC (Michels-Malpuech-Mingarelli-Carnevale) syndrome. This conclusion and the name 3MC syndrome was supported by Leal et al. (2008), who reported a brother and sister with an array of symptoms that overlapped the various syndromes. Further assertion of 3MC syndrome was by Rooryck et al. (2011) in an elaboration of its cause.
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Malpuech facial clefting syndrome
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Management
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Many of the congenital malformations found with Malpuech syndrome can be corrected surgically. These include cleft lip and palate, omphalocele, urogenital and craniofacial abnormalities, skeletal deformities such as a caudal appendage or scoliosis, and hernias of the umbilicus. The primary area of concern for these procedures applied to a neonate with congenital disorders including Malpuech syndrome regards the logistics of anesthesia. Methods like tracheal intubation for management of the airway during general anesthesia can be hampered by the even smaller, or maldeveloped mouth of the infant. For regional anesthesia, methods like spinal blocking are more difficult where scoliosis is present. In a 2010 report by Kiernan et al., a four-year-old girl with Malpuech syndrome was being prepared for an unrelated tonsillectomy and adenoidectomy. While undergoing intubation, insertion of a laryngoscope, needed to identify the airway for the placement of the endotracheal tube, was made troublesome by the presence of micrognathia attributed to the syndrome. After replacement with a laryngoscope of adjusted size, intubation proceeded normally. Successful general anesthesia followed.A rare follow-up of a male with Malpuech syndrome was presented by Priolo et al. (2007). Born at term from an uneventful pregnancy and delivery, the infant underwent a surgical repair of a cleft lip and palate. No problems were reported with the procedure. A heart abnormality, atrial septal defect, was also apparent but required no intervention. At age three years, intellectual disability, hyperactivity and obsessive compulsive disorder were diagnosed; hearing impairment was diagnosed at age six, managed with the use of hearing aids. Over the course of the decade that followed, a number of psychiatric evaluations were performed. At age 14, he exhibited a fear of physical contact; at age 15, he experienced a severe psychotic episode, characterized by agitation and a loss of sociosexual inhibition. This array of symptoms were treated pharmacologically (with prescription medications). He maintained a low level of mental deficiency by age 17, with moments of compulsive echolalia.
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Malpuech facial clefting syndrome
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History
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The incidence of Malpuech syndrome has not been determined. A 1999 report by Crisponi et al. suggested that only about 12 individuals worldwide were affected by the disorder at that time. The syndrome was first reported by Guilliaume Malpuech and colleagues in 1983, observed in four children of unspecified gender in what was described as a gypsy family. The children included three siblings and their first cousin; the family was known to be highly consanguineous.
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False singular
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False singular
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In English grammar, a false singular occurs when a singular noun ending in a s or z sound is understood as a plural from which a new singular is constructed. The false singular is a form of back-formation.
Some false singulars become standard English. For example, pea was originally a false singular from pease pl. peasen. (The old word remains in the phrase pease porridge.) The non-standard historical forms Chinee and Portuguee are also false singulars, from Chinese and Portuguese.
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Halyard bend
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Halyard bend
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Studding-Sail Bend is a way to attach the end of a rope at right angle to a cylindrical object such as a beam.
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Halyard bend
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Tying
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wrap the end two or more times around the object make the end hook around the standing part and under all wrappings, to come out by the last wrap make the end turn back and cross over the wrappings, to tuck/pass it under the first wrapHalyard bend may be considered to be the "double-loop-around, and single-tuck-under" version of timber hitch which itself is usually tied as "single-loop-around, and double-tuck-under".
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Secondary growth
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Secondary growth
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In botany, secondary growth is the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate, and gives rise to primary tissue. Secondary growth occurs in most seed plants, but monocots usually lack secondary growth. If they do have secondary growth, it differs from the typical pattern of other seed plants.
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Secondary growth
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Secondary growth
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The formation of secondary vascular tissues from the cambium is a characteristic feature of dicotyledons and gymnosperms. In certain monocots, the vascular tissues are also increased after the primary growth is completed but the cambium of these plants is of a different nature. In the living pteridophytes this feature is extremely rare, only occurring in Isoetes.
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Secondary growth
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Lateral meristems
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In many vascular plants, secondary growth is the result of the activity of the two lateral meristems, the cork cambium and vascular cambium. Arising from lateral meristems, secondary growth increases the width of the plant root or stem, rather than its length. As long as the lateral meristems continue to produce new cells, the stem or root will continue to grow in diameter. In woody plants, this process produces wood, and shapes the plant into a tree with a thickened trunk.
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Secondary growth
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Lateral meristems
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Because this growth usually ruptures the epidermis of the stem or roots, plants with secondary growth usually also develop a cork cambium. The cork cambium gives rise to thickened cork cells to protect the surface of the plant and reduce water loss. If this is kept up over many years, this process may produce a layer of cork. In the case of the cork oak it will yield harvestable cork.
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Secondary growth
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In nonwoody plants
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Secondary growth also occurs in many nonwoody plants, e.g. tomato, potato tuber, carrot taproot and sweet potato tuberous root. A few long-lived leaves also have secondary growth.
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Secondary growth
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Abnormal secondary growth
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Abnormal secondary growth does not follow the pattern of a single vascular cambium producing xylem to the inside and phloem to the outside as in ancestral lignophytes. Some dicots have anomalous secondary growth, e.g. in Bougainvillea a series of cambia arise outside the oldest phloem.Ancestral monocots lost their secondary growth and their stele has changed in a way it could not be recovered without major changes that are very unlikely to occur. Monocots either have no secondary growth, as is the ancestral case, or they have an "anomalous secondary growth" of some type, or, in the case of palms, they enlarge their diameter in what is called a sort of secondary growth or not depending on the definition given to the term. Palm trees increase their trunk diameter due to division and enlargement of parenchyma cells, which is termed "primary gigantism" because there is no production of secondary xylem and phloem tissues, or sometimes "diffuse secondary growth". In some other monocot stems as in Yucca and Dracaena with anomalous secondary growth, a cambium forms, but it produces vascular bundles and parenchyma internally and just parenchyma externally. Some monocot stems increase in diameter due to the activity of a primary thickening meristem, which is derived from the apical meristem.
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Fenoprop
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Fenoprop
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Fenoprop, also called 2,4,5-TP, is the organic compound 2-(2,4,5-trichlorophenoxy)propionic acid. It is a phenoxy herbicide and a plant growth regulator, an analog of 2,4,5-T in which the latter's acetic acid sidechain is replaced with a propionate group (with an extra CH3). The addition of this extra methyl group creates a chiral centre in the molecule and useful biological activity is found only in the (2R)-isomer. The compound's mechanism of action is to mimic the auxin growth hormone indoleacetic acid (IAA). When sprayed on plants it induces rapid, uncontrolled growth. As with 2,4,5-T, fenoprop is toxic to shrubs and trees.
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Fenoprop
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Fenoprop
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The name Silvex was used in the USA but it has been banned from use there since 1985. According to the Environmental Protection Agency its greatest use was as a postemergence herbicide for control of woody plants, and broadleaf herbaceous weeds in rice and bluegrass turf, in sugarcane, in rangeland improvement programs and on lawns.
Fenoprop and some of its esters were in use from 1945 but are now obsolete.
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Cantic octagonal tiling
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Cantic octagonal tiling
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In geometry, the tritetratrigonal tiling or shieldotritetragonal tiling is a uniform tiling of the hyperbolic plane. It has Schläfli symbol of t1,2(4,3,3). It can also be named as a cantic octagonal tiling, h2{8,3}.
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Signal-regulatory protein alpha
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Signal-regulatory protein alpha
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Signal regulatory protein α (SIRPα) is a regulatory membrane glycoprotein from SIRP family expressed mainly by myeloid cells and also by stem cells or neurons.
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Signal-regulatory protein alpha
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Signal-regulatory protein alpha
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SIRPα acts as inhibitory receptor and interacts with a broadly expressed transmembrane protein CD47 also called the "don't eat me" signal. This interaction negatively controls effector function of innate immune cells such as host cell phagocytosis. SIRPα diffuses laterally on the macrophage membrane and accumulates at a phagocytic synapse to bind CD47 and signal 'self', which inhibits the cytoskeleton-intensive process of phagocytosis by the macrophage. This is analogous to the self signals provided by MHC class I molecules to NK cells via Ig-like or Ly49 receptors. NB. Protein shown to the right is CD47 not SIRP α.
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Signal-regulatory protein alpha
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Structure
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The cytoplasmic region of SIRPα is highly conserved between rats, mice and humans. Cytoplasmic region contains a number of tyrosine residues, which likely act as ITIMs. Upon CD47 ligation, SIRPα is phosphorylated and recruits phosphatases like SHP1 and SHP2. The extracellular region contains three Immunoglobulin superfamily domains – single V-set and two C1-set IgSF domains. SIRP β and γ have the similar extracellular structure but different cytoplasmic regions giving contrasting types of signals. SIRP α polymorphisms are found in ligand-binding IgSF V-set domain but it does not affect ligand binding. One idea is that the polymorphism is important to protect the receptor of pathogens binding.
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Signal-regulatory protein alpha
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Ligands
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SIRPα recognizes CD47, an anti-phagocytic signal that distinguishes live cells from dying cells. CD47 has a single Ig-like extracellular domain and five membrane spanning regions. The interaction between SIRPα and CD47 can be modified by endocytosis or cleavage of the receptor, or interaction with surfactant proteins. Surfactant protein A and D are soluble ligands, highly expressed in the lungs, that bind to the same region of SIRPα as CD47 and can therefore competitively block binding.
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Signal-regulatory protein alpha
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Signalling
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The extracellular domain of SIRP α binds to CD47 and transmits intracellular signals through its cytoplasmic domain. CD47-binding is mediated through the NH2-terminal V-like domain of SIRP α. The cytoplasmic region contains four ITIMs that become phosphorylated after binding of ligand. The phosphorylation mediates activation of tyrosine kinase SHP2. SIRP α has been shown to bind also phosphatase SHP1, adaptor protein SCAP2 and FYN-binding protein. Recruitment of SHP phosphatases to the membrane leads to the inhibition of myosin accumulation at the cell surface and results in the inhibition of phagocytosis.
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Signal-regulatory protein alpha
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Cancer
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Cancer cells highly expressed CD47 that activate SIRP α and inhibit macrophage-mediated destruction. In one study, they engineered high-affinity variants of SIRP α that antagonized CD47 on cancer cells and caused increase phagocytosis of cancer cells. Another study (in mice) found anti-SIRPα antibodies helped macrophages to reduce cancer growth and metastasis, alone and in synergy with other cancer treatments.
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ClinVar
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ClinVar
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ClinVar is a public archive with free access to reports on the relationships between human variations and phenotypes, with supporting evidence. The database includes germline and somatic variants of any size, type or genomic location. Interpretations are submitted by clinical testing laboratories, research laboratories, locus-specific databases, UniProt, expert panels and practical guidelines.
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Contract manufacturing organization
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Contract manufacturing organization
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A contract manufacturing organization (CMO), more recently referred to (and more commonly used now) as a contract development and manufacturing organization (CDMO) to avoid the acronym confusion of Chief Medical Officer or Clinical Monitoring Organization in the pharma industry, is a company that serves other companies in the pharmaceutical industry on a contract basis to provide comprehensive services from drug development through drug manufacturing. This allows major pharmaceutical companies to outsource those aspects of the business, which can help with scalability or can allow the major company to focus on drug discovery and drug marketing instead.
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Contract manufacturing organization
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Contract manufacturing organization
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Services offered by CDMOs include, but are not limited to: pre-formulation, formulation development, stability studies, method development, pre-clinical and Phase I clinical trial materials, late-stage clinical trial materials, formal stability, scale-up, registration batches and commercial production.CDMOs are contract manufacturers, yet they provide development as a standard part of their services.
Their customers are not only expecting competitive pricing, but also regulatory compliance, flexibility on the production capability and on time delivery. Overall it is required that CMO complies with good manufacturing practice from their client and regulatory bodies such as Food and Drug Administration.
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Contract manufacturing organization
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Overview
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The pharmaceutical market uses outsourcing services from providers in the form of contract research organizations (CROs) who work on very early-stage drug development on very small scale providing medicinal chemistry services. These are now often called CDROs as they provide some small scale development work. CDMOs work on the scale-up and later stages of drug development often preparing materials ranging from hundreds of grams to multi-kilo amounts. As the drug moves through the various clinical stages, the volumes tend to grow as well. Commercial scale amounts could range to metric tons. Over the years, the concept of a comprehensive single-source provider from drug development (a one-stop shop) through commercial manufacture of drug substance and drug product has been tried to varying success.
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Contract manufacturing organization
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Overview
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CDMOs are a response to the competitive international nature of the pharmaceutical market as well as the increasing demand for outsourced services. The best-positioned service providers focus on a specific technology or dosage form and promote end-to-end continuity and efficiency for their outsourcing clients. With lower-cost international manufacturers capturing an increasing percentage of the contract manufacturing market, specialization may be an effective hedge against loss of market share.
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Contract manufacturing organization
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History
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Before the financial crisis of 2007–2008, 75% of the candidate that outsourced services were small and mid-sized biotechnology and pharmaceutical companies. Following the financial crash in 2008 the CMO industry started to be funded by private equity as a result of a substantial growth and a more qualified management. The one-stop CDMO concept could be the direction the industry is heading by offering the whole spectrum of development services (e.g. development, production and analysis).The acquisitions that have been finalized in 2017 in CMO and CDMO industry brought some of these companies to a level that allows them to compete with global bio/pharma companies. The value of the mergers and acquisitions in 2017 was likely to exceed $20 billion, below are some examples of these M&A:Another aspect of these acquisition is coming from CMO that are acquiring manufacturing site from bio/pharma companies. In 2017, Pfizer established a manufacturing site in Liscate, Italy, which was followed that same year by AstraZeneca in Reims, France. Novartis Sandoz acquired a site in Boucherville, Canada in 2018, as well as Glaxo Smith Kline, which began manufacturing out of South Carolina in the United States. Samsung Biologics built three manufacturing plants with a capacity of more than 360,000 liters, making it the world's largest contract-based manufacturer in the biopharmaceutical sector at a single site as of 2018.The industry has experienced an increase in private equity investment and this has led to the consolidation of choices in the CDMO industry as many larger CDMOs have been formed. Many of those are active at aiming to be a larger scale suppliers in the CDMO environment but the number of attractive acquisitions are limited. One could argue that this has had both positive and negative effects on the industry. Larger pharma companies like the idea of a larger CDMO while smaller pharma companies tend to see it more difficult to get the kind of service they expect.
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Contract manufacturing organization
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Advantages
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The bio/pharma companies used to build and staff dedicated manufacturing capacities for drugs in development only to see them cancelled if the product failed in Phase III of clinical research; working with a CDMO limits that financial risk. Using a CDMO also allows drug and biologic manufacturers to get advantage of specific expertise and capability. Some CDMOs are specialized in manufacturing of specialty products or formulations which some pharmaceutical companies may not have the capability to produce in house. In these situations, contracting with a CDMO may be a faster and less costly solution than developing new manufacturing capabilities.
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Contract manufacturing organization
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Disadvantages
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The pharmaceutical client using the services of a CDMO does not have direct control of the project in regard to scheduling, cost, quality, or accountability yet should be heavily invested to work closely with the CDMO partner to ensure success. Data security can be an issue when considering a CDMO, as intellectual property and other proprietary data are exchanged between client and service provider.
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Contract manufacturing organization
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Disadvantages
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One of the major risk remains in the lack of control over the CDMO's compliance for the client, for example when an FDA warning letter is issued, a resulting interruption of production may result in major delay or interruption of shipping thus it is critical to properly vet the selected CDMO. The rise of the CDMO industry led to an increase of inspectors from various divisions of the Food and Drug Administration (e.g.: Center for Biologics Evaluation and Research or Center for Drug Evaluation and Research).
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Dobson unit
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Dobson unit
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The Dobson unit (DU) is a unit of measurement of the amount of a trace gas in a vertical column through the Earth's atmosphere. It originated, and continues to be primarily used in respect to, atmospheric ozone, whose total column amount, usually termed "total ozone", and sometimes "column abundance", is dominated by the high concentrations of ozone in the stratospheric ozone layer.
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Dobson unit
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Dobson unit
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The Dobson unit is defined as the thickness (in units of 10 μm) of that layer of pure gas which would be formed by the total column amount at standard conditions for temperature and pressure (STP). This is sometimes referred to as a 'milli-atmo-centimeter'. A typical column amount of 300 DU of atmospheric ozone therefore would form a 3 mm layer of pure gas at the surface of the Earth if its temperature and pressure conformed to STP.
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Dobson unit
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Dobson unit
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The Dobson unit is named after Gordon Dobson, a researcher at the University of Oxford who in the 1920s built the first instrument to measure total ozone from the ground, making use of a double prism monochromator to measure the differential absorption of different bands of solar ultraviolet radiation by the ozone layer. This instrument, called the Dobson ozone spectrophotometer, has formed the backbone of the global network for monitoring atmospheric ozone and was the source of the discovery in 1984 of the Antarctic ozone hole.
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Dobson unit
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Ozone
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NASA uses a baseline value of 220 DU for ozone. This was chosen as the starting point for observations of the Antarctic ozone hole, since values of less than 220 Dobson units were not found before 1979. Also, from direct measurements over Antarctica, a column ozone level of less than 220 Dobson units is a result of the ozone loss from chlorine and bromine compounds.
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Dobson unit
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Sulfur dioxide
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In addition, Dobson units are often used to describe total column densities of sulfur dioxide, which occurs in the atmosphere in small amounts due to the combustion of fossil fuels, from biological processes releasing dimethyl sulfide, or by natural combustion such as forest fires. Large amounts of sulfur dioxide may be released into the atmosphere as well by volcanic eruptions. The Dobson unit is used to describe total column amounts of sulfur dioxide because it appeared in the early days of ozone remote sensing on ultraviolet satellite instruments (such as TOMS).
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Dobson unit
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Derivation
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The Dobson unit arises from the ideal gas law PV=nRT, where P and V are pressure and volume respectively, and n, R and T are the number of moles of gas, the gas constant (8.314 J/(mol·K)), and T is temperature in kelvins (K).
The number density of air is the number of molecules or atoms per unit volume: air =AavnV, and when plugged into the real gas law, the number density of air is found by using pressure, temperature and the real gas constant: air =AavPRT.
The number density (molecules/volume) of air at standard temperature and pressure (T = 273 K and P = 101325 Pa) is, by using this equation, air 6.02 10 23 molecules mol 101325 Pa 8.314 mol K 273 K.
With some unit conversions of joules to pascal cubic meters, the equation for molecules/volume is 6.02 10 23 molecules mol 101325 Pa 8.314 Pa mol K 273 2.69 10 25 molecules ⋅m−3.
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