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15,716,827 | https://en.wikipedia.org/wiki/Anonymous%20%28hacker%20group%29 | Anonymous is a decentralized international activist and hacktivist collective and movement primarily known for its various cyberattacks against several governments, government institutions and government agencies, corporations and the Church of Scientology.
Anonymous originated in 2003 on the imageboard 4chan representing the concept of many online and offline community users simultaneously existing as an "anarchic", digitized "global brain" or "hivemind". Anonymous members (known as anons) can sometimes be distinguished in public by the wearing of Guy Fawkes masks in the style portrayed in the graphic novel and film V for Vendetta. Some anons also opt to mask their voices through voice changers or text-to-speech programs.
Dozens of people have been arrested for involvement in Anonymous cyberattacks in countries including the United States, the United Kingdom, Australia, the Netherlands, South Africa, Spain, India, and Turkey. Evaluations of the group's actions and effectiveness vary widely. Supporters have called the group "freedom fighters" and digital Robin Hoods, while critics have described them as "a cyber lynch-mob" or "cyber terrorists". In 2012, Time called Anonymous one of the "100 most influential people" in the world. Anonymous' media profile diminished by 2018, but the group re-emerged in 2020 to support the George Floyd protests and other causes.
Philosophy
Internal dissent is also a regular feature of the group. A website associated with the group describes it as "an Internet gathering" with "a very loose and decentralized command structure that operates on ideas rather than directives". Gabriella Coleman writes of the group: "In some ways, it may be impossible to gauge the intent and motive of thousands of participants, many of who don't even bother to leave a trace of their thoughts, motivations, and reactions. Among those that do, opinions vary considerably."
Broadly speaking, Anons oppose Internet censorship and control and the majority of their actions target governments, organizations, and corporations that they accuse of censorship. Anons were early supporters of the global Occupy movement and the Arab Spring. Since 2008, a frequent subject of disagreement within Anonymous is whether members should focus on pranking and entertainment or more serious (and, in some cases, political) activism.
Because Anonymous has no leadership, no action can be attributed to the membership as a whole. Parmy Olson and others have criticized media coverage that presents the group as well-organized or homogeneous; Olson writes, "There was no single leader pulling the levers, but a few organizational minds that sometimes pooled together to start planning a stunt." Some members protest using legal means, while others employ illegal measures such as DDoS attacks and hacking. Membership is open to anyone who wishes to state they are a member of the collective; British journalist Carole Cadwalladr of The Observer compared the group's decentralized structure to that of al-Qaeda: "If you believe in Anonymous, and call yourself Anonymous, you are Anonymous." Olson, who formerly described Anonymous as a "brand", stated in 2012 that she now characterized it as a "movement" rather than a group: "anyone can be part of it. It is a crowd of people, a nebulous crowd of people, working together and doing things together for various purposes."
The group's few rules include not disclosing one's identity, not talking about the group, and not attacking media. Members commonly use the tagline "We are Anonymous. We are Legion. We do not forgive. We do not forget. Expect us." Brian Kelly writes that three of the group's key characteristics are "(1) an unrelenting moral stance on issues and rights, regardless of direct provocation; (2) a physical presence that accompanies
online hacking activity; and (3) a distinctive brand."
Journalists have commented that Anonymous' secrecy, fabrications, and media awareness pose an unusual challenge for reporting on the group's actions and motivations. Quinn Norton of Wired writes that: "Anons lie when they have no reason to lie. They weave vast fabrications as a form of performance. Then they tell the truth at unexpected and unfortunate times, sometimes destroying themselves in the process. They are unpredictable." Norton states that the difficulties in reporting on the group cause most writers, including herself, to focus on the "small groups of hackers who stole the limelight from a legion, defied their values, and crashed violently into the law" rather than "Anonymous's sea of voices, all experimenting with new ways of being in the world".
Arrests and trials
Since 2009, dozens of people have been arrested for involvement in Anonymous cyberattacks, in countries including the U.S., UK, Australia, the Netherlands, Spain, and Turkey. Anons generally protest these prosecutions and describe these individuals as martyrs to the movement. The July 2011 arrest of LulzSec member Topiary became a particular rallying point, leading to a widespread "Free Topiary" movement.
The first person to be sent to jail for participation in an Anonymous DDoS attack was Dmitriy Guzner, an American 19-year-old. He pleaded guilty to "unauthorized impairment of a protected computer" in November 2009 and was sentenced to 366 days in U.S. federal prison.
On June 13, 2011, officials in Turkey arrested 32 individuals that were allegedly involved in DDoS attacks on Turkish government websites. These members of Anonymous were captured in different cities of Turkey including Istanbul and Ankara. According to PC Magazine, these individuals were arrested after they attacked websites as a response to the Turkish government demand to ISPs to implement a system of filters that many have perceived as censorship.
Chris Doyon (alias "Commander X"), a self-described leader of Anonymous, was arrested in September 2011 for a cyberattack on the website of Santa Cruz County, California. He jumped bail in February 2012 and fled across the border into Canada.
In September 2012, journalist and Anonymous associate Barrett Brown, known for speaking to media on behalf of the group, was arrested hours after posting a video that appeared to threaten FBI agents with physical violence. Brown was subsequently charged with 17 offenses, including publishing personal credit card information from the Stratfor hack.
Operation Avenge Assange
Several law enforcement agencies took action after Anonymous' Operation Avenge Assange. In January 2011, British police arrested five male suspects between the ages of 15 and 26 with suspicion of participating in Anonymous DDoS attacks. During July 19–20, 2011, as many as 20 or more arrests were made of suspected Anonymous hackers in the US, UK, and Netherlands. According to the statements of U.S. officials, suspects' homes were raided and suspects were arrested in Alabama, Arizona, California, Colorado, Washington DC, Florida, Massachusetts, Nevada, New Mexico, and Ohio. Additionally, a 16-year-old boy was held by the police in south London on suspicion of breaching the Computer Misuse Act 1990, and four were held in the Netherlands.
AnonOps admin Christopher Weatherhead (alias "Nerdo"), a 22-year-old who had reportedly been intimately involved in organizing DDoS attacks during "Operation Payback", was convicted by a UK court on one count of conspiracy to impair the operation of computers in December 2012. He was sentenced to 18 months' imprisonment. Ashley Rhodes, Peter Gibson, and another male had already pleaded guilty to the same charge for actions between August 2010 and January 2011.
Analysis
Evaluations of Anonymous' actions and effectiveness vary widely. In a widely shared post, blogger Patrick Gray wrote that private security firms "secretly love" the group for the way in which it publicizes cyber security threats. Anonymous is sometimes stated to have changed the nature of protesting, and in 2012, Time called it one of the "100 most influential people" in the world.
In 2012, Public Radio International reported that the U.S. National Security Agency considered Anonymous a potential national security threat and had warned the president that it could develop the capability to disable parts of the U.S. power grid. In contrast, CNN reported in the same year that "security industry experts generally don't consider Anonymous a major player in the world of cybercrime" due to the group's reliance on DDoS attacks that briefly disabled websites rather than the more serious damage possible through hacking. One security consultant compared the group to "a jewelry thief that drives through a window, steal jewels, and rather than keep them, waves them around and tosses them out to a crowd ... They're very noisy, low-grade crimes." In its 2013 Threats Predictions report, McAfee wrote that the technical sophistication of Anonymous was in decline and that it was losing supporters due to "too many uncoordinated and unclear operations".
Graham Cluley, a security expert for Sophos, argued that Anonymous' actions against child porn websites hosted on a darknet could be counterproductive, commenting that while their intentions may be good, the removal of illegal websites and sharing networks should be performed by the authorities, rather than Internet vigilantes.
Some commentators also argued that the DDoS attacks by Anonymous following the January 2012 Stop Online Piracy Act protests had proved counterproductive. Molly Wood of CNET wrote that "[i]f the SOPA/PIPA protests were the Web's moment of inspiring, non-violent, hand-holding civil disobedience, #OpMegaUpload feels like the unsettling wave of car-burning hooligans that sweep in and incite the riot portion of the play." Dwight Silverman of the Houston Chronicle concurred, stating that "Anonymous' actions hurt the movement to kill SOPA/PIPA by highlighting online lawlessness." The Oxford Internet Institute's Joss Wright wrote that "In one sense the actions of Anonymous are themselves, anonymously and unaccountably, censoring websites in response to positions with which they disagree."
Gabriella Coleman has compared the group to the trickster archetype and said that "they dramatize the importance of anonymity and privacy in an era when both are rapidly eroding. Given that vast databases track us, given the vast explosion of surveillance, there's something enchanting, mesmerizing and at a minimum thought-provoking about Anonymous' interventions". When asked what good Anonymous had done for the world, Parmy Olson replied:
Quinn Norton of Wired wrote of the group in 2011:
Furthermore, Landers assessed the following in 2008:
Media portrayal
Sam Esmail shared in an interview with Motherboard that he was inspired by Anonymous when creating the USA Network hacktivist drama, Mr. Robot. Furthermore, Wired calls the "Omegas", a fictitious hacker group in the show, "a clear reference to the Anonymous offshoot known as LulzSec". In the TV series Elementary a hacktivist collective called "Everyone" plays a recurring role; there are several hints and similarities to Anonymous.
History
4chan raids (2003–2007)
The name Anonymous itself is inspired by the perceived anonymity under which users post images and comments on the Internet. Usage of the term Anonymous in the sense of a shared identity began on imageboards, particularly the /b/ board of 4chan, dedicated to random content and to raiding other websites. A tag of Anonymous is assigned to visitors who leave comments without identifying the originator of the posted content. Users of imageboards sometimes jokingly acted as if Anonymous was a single individual. The concept of the Anonymous entity advanced in 2004 when an administrator on the 4chan image board activated a "Forced_Anon" protocol that signed all posts as Anonymous. As the popularity of imageboards increased, the idea of Anonymous as a collective of unnamed individuals became an Internet meme.
Users of 4chan's /b/ board would occasionally join into mass pranks or raids. In a raid on July 12, 2006, for example, large numbers of 4chan readers invaded the Finnish social networking site Habbo Hotel with identical avatars; the avatars blocked regular Habbo members from accessing the digital hotel's pool, stating it was "closed due to fail and AIDS". Future LulzSec member Topiary became involved with the site at this time, inviting large audiences to listen to his prank phone calls via Skype. Due to the growing traffic on 4chan's board, users soon began to plot pranks off-site using Internet Relay Chat (IRC). These raids resulted in the first mainstream press story on Anonymous, a report by Fox station KTTV in Los Angeles, California in the U.S. The report called the group "hackers on steroids", "domestic terrorists", and an "Internet hate machine".
Encyclopedia Dramatica (2004–present)
Encyclopedia Dramatica was founded in 2004 by Sherrod DeGrippo, initially as a means of documenting gossip related to LiveJournal, but it quickly was adopted as a major platform by Anonymous for parody and other purposes. The not safe for work site celebrates a subversive "trolling culture", and documents Internet memes, culture, and events, such as mass pranks, trolling events, "raids", large-scale failures of Internet security, and criticism of Internet communities that are accused of self-censorship to gain prestige or positive coverage from traditional and established media outlets. Journalist Julian Dibbell described Encyclopedia Dramatica as the site "where the vast parallel universe of Anonymous in-jokes, catchphrases, and obsessions is lovingly annotated, and you will discover an elaborate trolling culture: Flamingly racist and misogynist content lurks throughout, all of it calculated to offend." The site also played a role in the anti-Scientology campaign of Project Chanology.
On April 14, 2011, the original URL of the site was redirected to a new website named Oh Internet that bore little resemblance to Encyclopedia Dramatica. Parts of the ED community harshly criticized the changes. In response, Anonymous launched "Operation Save ED" to rescue and restore the site's content. The Web Ecology Project made a downloadable archive of former Encyclopedia Dramatica content. The site's reincarnation was initially hosted at encyclopediadramatica.ch on servers owned by Ryan Cleary, who later was arrested in relation to attacks by LulzSec against Sony.
Project Chanology (2008)
Anonymous first became associated with hacktivism in 2008 following a series of actions against the Church of Scientology known as Project Chanology. On January 15, 2008, the gossip blog Gawker posted a video in which celebrity Scientologist Tom Cruise praised the religion; and the Church responded with a cease-and-desist letter for violation of copyright. 4chan users organized a raid against the Church in retaliation, prank-calling its hotline, sending black faxes designed to waste ink cartridges, and launching DDoS attacks against its websites.
The DDoS attacks were at first carried out with the Gigaloader and JMeter applications. Within a few days, these were supplanted by the Low Orbit Ion Cannon (LOIC), a network stress-testing application allowing users to flood a server with TCP or UDP packets. The LOIC soon became a signature weapon in the Anonymous arsenal; however, it would also lead to a number of arrests of less experienced Anons who failed to conceal their IP addresses. Some operators in Anonymous IRC channels incorrectly told or lied to new volunteers that using the LOIC carried no legal risk.
During the DDoS attacks, a group of Anons uploaded a YouTube video in which a robotic voice speaks on behalf of Anonymous, telling the "leaders of Scientology" that "For the good of your followers, for the good of mankind—for the laughs—we shall expel you from the Internet." Within ten days, the video had attracted hundreds of thousands of views.
With more than 10 thousand followers on their IRC server waiting for instructions, they felt they had to come up with something, and got the idea of a worldwide protest. Because they both wanted to use a symbol or image to unify the protests, and because all protesters were supposed to be anonymous, it was decided to use a mask. Due to shipment problems caused by the short amount of time to prepare, they improvised and called all the costume and comic book-shops in the major cities around the world, and found that the only mask available in all the cities was the Guy Fawkes mask from the graphic novel and film V for Vendetta, in which an anarchist revolutionary battles a totalitarian government. The suggestion of the choice of mask was well received. On February 10, thousands of Anonymous joined simultaneous protests at Church of Scientology facilities in 142 cities in 43 countries. The stylized Guy Fawkes masks soon became a popular symbol for Anonymous. In-person protests against the Church continued throughout the year, including "Operation Party Hard" on March 15 and "Operation Reconnect" on April 12. However, by mid-year, they were drawing far fewer protesters, and many of the organizers in IRC channels had begun to drift away from the project.
Operation Payback (2010)
By the start of 2009, Scientologists had stopped engaging with protesters and had improved online security, and actions against the group had largely ceased. A period of infighting followed between the politically engaged members (called "moralfags" in the parlance of 4chan) and those seeking to provoke for entertainment (trolls). By September 2010, the group had received little publicity for a year and faced a corresponding drop in member interest; its raids diminished greatly in size and moved largely off of IRC channels, organizing again from the chan boards, particularly /b/.
In September 2010, however, Anons became aware of Aiplex Software, an Indian software company that contracted with film studios to launch DDoS attacks on websites used by copyright infringers, such as The Pirate Bay. Coordinating through IRC, Anons launched a DDoS attack on September 17 that shut down Aiplex's website for a day. Primarily using LOIC, the group then targeted the Recording Industry Association of America (RIAA) and the Motion Picture Association of America (MPAA), successfully bringing down both sites. On September 19, future LulzSec member Mustafa Al-Bassam (known as "Tflow") and other Anons hacked the website of Copyright Alliance, an anti-infringement group, and posted the name of the operation: "Payback Is A Bitch", or "Operation Payback" for short. Anons also issued a press release, stating:
As IRC network operators were beginning to shut down networks involved in DDoS attacks, Anons organized a group of servers to host an independent IRC network, titled AnonOps. Operation Payback's targets rapidly expanded to include the British law firm ACS:Law, the Australian Federation Against Copyright Theft, the British nightclub Ministry of Sound, the Spanish copyright society Sociedad General de Autores y Editores, the U.S. Copyright Office, and the website of Gene Simmons of Kiss. By October 7, 2010, total downtime for all websites attacked during Operation Payback was 537.55 hours.
In November 2010, the organization WikiLeaks began releasing hundreds of thousands of leaked U.S. diplomatic cables. In the face of legal threats against the organization by the U.S. government, Amazon.com booted WikiLeaks from its servers, and PayPal, MasterCard, and Visa cut off service to the organization. Operation Payback then expanded to include "Operation Avenge Assange", and Anons issued a press release declaring PayPal a target. Launching DDoS attacks with the LOIC, Anons quickly brought down the websites of the PayPal blog; PostFinance, a Swiss financial company denying service to WikiLeaks; EveryDNS, a web-hosting company that had also denied service; and the website of U.S. Senator Joe Lieberman, who had supported the push to cut off services.
On December 8, Anons launched an attack against PayPal's main site. According to Topiary, who was in the command channel during the attack, the LOIC proved ineffective, and Anons were forced to rely on the botnets of two hackers for the attack, marshaling hijacked computers for a concentrated assault. Security researcher Sean-Paul Correll also reported that the "zombie computers" of involuntary botnets had provided 90% of the attack. Topiary states that he and other Anons then "lied a bit to the press to give it that sense of abundance", exaggerating the role of the grassroots membership. However, this account was disputed.
The attacks brought down PayPal.com for an hour on December 8 and another brief period on December 9. Anonymous also disrupted the sites for Visa and MasterCard on December 8. Anons had announced an intention to bring down Amazon.com as well, but failed to do so, allegedly because of infighting with the hackers who controlled the botnets. PayPal estimated the damage to have cost the company US$5.5 million. It later provided the IP addresses of 1,000 of its attackers to the FBI, leading to at least 14 arrests. On Thursday, December 5, 2013, 13 of the PayPal 14 pleaded guilty to taking part in the attacks.
2011–2012
In the years following Operation Payback, targets of Anonymous protests, hacks, and DDoS attacks continued to diversify. Beginning in January 2011, Anons took a number of actions known initially as Operation Tunisia in support of Arab Spring movements. Tflow created a script that Tunisians could use to protect their web browsers from government surveillance, while fellow future LulzSec member Hector Xavier Monsegur (alias "Sabu") and others allegedly hijacked servers from a London web-hosting company to launch a DDoS attack on Tunisian government websites, taking them offline. Sabu also used a Tunisian volunteer's computer to hack the website of Prime Minister Mohamed Ghannouchi, replacing it with a message from Anonymous. Anons also helped Tunisian dissidents share videos online about the uprising. In Operation Egypt, Anons collaborated with the activist group Telecomix to help dissidents access government-censored websites. Sabu and Topiary went on to participate in attacks on government websites in Bahrain, Egypt, Libya, Jordan, and Zimbabwe.
Tflow, Sabu, Topiary, and Ryan Ackroyd (known as "Kayla") collaborated in February 2011 on a cyber-attack against Aaron Barr, CEO of the computer security firm HBGary Federal, in retaliation for his research on Anonymous and his threat to expose members of the group. Using a SQL injection weakness, the four hacked the HBGary site, used Barr's captured password to vandalize his Twitter feed with racist messages, and released an enormous cache of HBGary's e-mails in a torrent file on Pirate Bay. The e-mails stated that Barr and HBGary had proposed to Bank of America a plan to discredit WikiLeaks in retaliation for a planned leak of Bank of America documents, and the leak caused substantial public relations harm to the firm as well as leading one U.S. congressman to call for a congressional investigation. Barr resigned as CEO before the end of the month.
Several attacks by Anons have targeted organizations accused of homophobia. In February 2011, an open letter was published on AnonNews.org threatening the Westboro Baptist Church, an organization based in Kansas in the U.S. known for picketing funerals with signs reading "God Hates Fags". During a live radio current affairs program in which Topiary debated church member Shirley Phelps-Roper, CosmoTheGod hacked one of the organization's websites. After the church announced its intentions in December 2012 to picket the funerals of the Sandy Hook Elementary School shooting victims, CosmoTheGod published the names, phone numbers, and e-mail and home addresses of church members and brought down GodHatesFags.com with a DDoS attack. In August 2012, Anons hacked the site of Ugandan Prime Minister Amama Mbabazi in retaliation for the Parliament of Uganda's consideration of an anti-homosexuality law permitting capital punishment.
In April 2011, Anons launched a series of attacks against Sony in retaliation for trying to stop hacks of the PlayStation 3 game console. More than 100 million Sony accounts were compromised, and the Sony services Qriocity and PlayStation Network were taken down for a month apiece by cyberattacks.
In July 2011, Anonymous announced the launch of its social media platform Anonplus. This came after Anonymous' presence was removed from Google+. The site was later hacked by a Turkish hackers group who placed a message on the front page and replaced its logo with a picture of a dog.
In August 2011, Anons launched an attack against BART in San Francisco, which they dubbed #OpBart. The attack, made in response to the killing of Charles Hill a month prior, resulted in customers' personal information leaked onto the group's website.
When the Occupy Wall Street protests began in New York City in September 2011, Anons were early participants and helped spread the movement to other cities such as Boston. In October, some Anons attacked the website of the New York Stock Exchange while other Anons publicly opposed the action via Twitter. Some Anons also helped organize an Occupy protest outside the London Stock Exchange on May 1, 2012.
Anons launched Operation Darknet in October 2011, targeting websites hosting child pornography. In particular, the group hacked a child pornography site called "Lolita City" hosted by Freedom Hosting, releasing 1,589 usernames from the site. Anons also said that they had disabled forty image-swapping pedophile websites that employed the anonymity network Tor. In 2012, Anons leaked the names of users of a suspected child porn site in OpDarknetV2. Anonymous launched the #OpPedoChat campaign on Twitter in 2012 as a continuation of Operation Darknet. In attempt to eliminate child pornography from the internet, the group posted the emails and IP addresses of suspected pedophiles on the online forum PasteBin.
In 2011, the Koch Industries website was attacked following their attack upon union members, resulting in their website being made inaccessible for 15 minutes. In 2013, one member, a 38-year-old truck driver, pleaded guilty when accused of participating in the attack for a period of one minute, and received a sentence of two years federal probation, and ordered to pay $183,000 restitution, the amount Koch stated they paid a consultancy organization, despite this being only a denial of service attack.
On January 19, 2012, the U.S. Department of Justice shut down the file-sharing site Megaupload on allegations of copyright infringement. Anons responded with a wave of DDoS attacks on U.S. government and copyright organizations, shutting down the sites for the RIAA, MPAA, Broadcast Music, Inc., and the FBI.
In April 2012, Anonymous hacked 485 Chinese government websites, some more than once, to protest the treatment of their citizens. They urged people to "fight for justice, fight for freedom, [and] fight for democracy".
In 2012, Anonymous launched Operation Anti-Bully: Operation Hunt Hunter in retaliation to Hunter Moore's revenge porn site, "Is Anyone Up?" Anonymous crashed Moore's servers and publicized much of his personal information online, including his social security number. The organization also published the personal information of Andrew Myers, the proprietor of "Is Anyone Back", a copycat site of Moore's "Is Anyone Up?"
In response to Operation Pillar of Defense, a November 2012 Israeli military operation in the Gaza Strip, Anons took down hundreds of Israeli websites with DDoS attacks. Anons pledged another "massive cyberassault" against Israel in April 2013 in retaliation for its actions in Gaza, promising to "wipe Israel off the map of the Internet". However, its DDoS attacks caused only temporary disruptions, leading cyberwarfare experts to suggest that the group had been unable to recruit or hire botnet operators for the attack.
2013
On November 5, 2013, Anonymous protesters gathered around the world for the Million Mask March. Demonstrations were held in 400 cities around the world to coincide with Guy Fawkes Night.
Operation Safe Winter was an effort to raise awareness about homelessness through the collection, collation, and redistribution of resources. This program began on November 7, 2013 after an online call to action from Anonymous UK. Three missions using a charity framework were suggested in the original global spawning a variety of direct actions from used clothing drives to pitch in community potlucks feeding events in the UK, US and Turkey. The #OpSafeWinter call to action quickly spread through the mutual aid communities like Occupy Wall Street and its offshoot groups like the open-source-based OccuWeather. With the addition of the long-term mutual aid communities of New York City and online hacktivists in the US, it took on an additional three suggested missions. Encouraging participation from the general public, this operation has raised questions of privacy and the changing nature of the Anonymous community's use of monikers. The project to support those living on the streets while causing division in its own online network has been able to partner with many efforts and organizations not traditionally associated with Anonymous or online activists.
2014
In the wake of the fatal police shooting of unarmed African-American Michael Brown in Ferguson, Missouri, "Operation Ferguson"—a hacktivist organization that claimed to be associated with Anonymous—organized cyberprotests against police, setting up a website and a Twitter account to do so. The group promised that if any protesters were harassed or harmed, they would attack the city's servers and computers, taking them offline. City officials said that e-mail systems were targeted and phones died, while the Internet crashed at the City Hall. Prior to August 15, members of Anonymous corresponding with Mother Jones said that they were working on confirming the identity of the undisclosed police officer who shot Brown and would release his name as soon as they did. On August 14, Anonymous posted on its Twitter feed what it claimed was the name of the officer involved in the shooting. However, police said the identity released by Anonymous was incorrect. Twitter subsequently suspended the Anonymous account from its service.
It was reported on November 19, 2014, that Anonymous had declared cyber war on the Ku Klux Klan (KKK) the previous week, after the KKK had made death threats following the Ferguson riots. They hacked the KKK's Twitter account, attacked servers hosting KKK sites, and started to release the personal details of members.
On November 24, 2014, Anonymous shut down the Cleveland city website and posted a video after Tamir Rice, a twelve-year-old boy armed only with a BB gun, was shot to death by a police officer in a Cleveland park. Anonymous also used BeenVerified to uncover the phone number and address of a police officer involved in the shooting.
2015
In January 2015, Anonymous released a video and a statement via Twitter condemning the attack on Charlie Hebdo, in which 12 people, including eight journalists, were fatally shot. The video, claiming that it is "a message for al-Qaeda, the Islamic State and other terrorists", was uploaded to the group's Belgian account. The announcement stated that "We, Anonymous around the world, have decided to declare war on you, the terrorists" and promises to avenge the killings by "shut[ting] down your accounts on all social networks." On January 12, they brought down a website that was suspected to belong to one of these groups. Critics of the action warned that taking down extremists' websites would make them harder to monitor.
On June 17, 2015, Anonymous claimed responsibility for a Denial of Service attack against Canadian government websites in protest of the passage of bill C-51—an anti-terror legislation that grants additional powers to Canadian intelligence agencies. The attack temporarily affected the websites of several federal agencies.
On October 28, 2015, Anonymous announced that it would reveal the names of up to 1,000 members of the Ku Klux Klan and other affiliated groups, stating in a press release, "You are terrorists that hide your identities beneath sheets and infiltrate society on every level. The privacy of the Ku Klux Klan no longer exists in cyberspace." On November 2, a list of 57 phone numbers and 23 email addresses (that allegedly belong to KKK members) was reportedly published and received media attention. However, a tweet from the "@Operation_KKK" Twitter account the same day denied it had released that information The group stated it planned to, and later did, reveal the names on November 5.
Since 2013, Saudi Arabian hacktivists have been targeting government websites protesting the actions of the regime. These actions have seen attacks supported by the possibly Iranian backed Yemen Cyber Army. An offshoot of Anonymous self-described as Ghost Security or GhostSec started targeting Islamic State-affiliated websites and social media handles.
In November 2015, Anonymous announced a major, sustained operation against ISIS following the November 2015 Paris attacks, declaring: "Anonymous from all over the world will hunt you down. You should know that we will find you and we will not let you go." ISIS responded on Telegram by calling them "idiots", and asking "What they hack?" By the next day, however, Anonymous claimed to have taken down 3,824 pro-ISIS Twitter accounts, and by the third day more than 5,000, and to have doxxed ISIS recruiters. A week later, Anonymous increased their claim to 20,000 pro-ISIS accounts and released a list of the accounts. The list included the Twitter accounts of Barack Obama, Hillary Clinton, The New York Times, and BBC News. The BBC reported that most of the accounts on the list appeared to be still active. A spokesman for Twitter told The Daily Dot that the company is not using the lists of accounts being reported by Anonymous, as they have been found to be "wildly inaccurate" and include accounts used by academics and journalists.
In 2015, a group that claimed to be affiliated with Anonymous, calling themselves as AnonSec, claimed to have hacked and gathered almost 276 GB of data from NASA servers including NASA flight and radar logs and videos, and also multiple documents related to ongoing research. AnonSec group also claimed gaining access of a Global Hawk Drone of NASA, and released some video footage purportedly from the drone's cameras. A part of the data was released by AnonSec on Pastebin service, as an Anon Zine. NASA has denied the hack, asserting that the control of the drones were never compromised, but has acknowledged that the photos released along with the content are real photographs of its employees, but that most of these data are already available in the public domain.
2016
The Blink Hacker Group, associating themselves with the Anonymous group, claimed to have hacked the Thailand prison websites and servers. The compromised data has been shared online, with the group claiming that they give the data back to Thailand Justice and the citizens of Thailand as well. The hack was done in response to news from Thailand about the mistreatment of prisoners in Thailand.
A group calling themselves Anonymous Africa launched a number of DDoS attacks on websites associated with the controversial South African Gupta family in mid-June 2016. Gupta-owned companies targeted included the websites of Oakbay Investments, The New Age, and ANN7. The websites of the South African Broadcasting Corporation, the political party Economic Freedom Fighters, and Zimbabwe's Zanu-PF were also attacked for "politicising racism."
Late 2010s
In late 2017, the QAnon conspiracy theory first emerged on 4chan, and adherents used similar terminology and branding to Anonymous. In response, in 2018, anti-Trump members of Anonymous warned that QAnon was stealing the collective's branding and vowed to oppose the theory.
However, in 2017, some members stood against similar groups and QAnon itself.
2020
In February 2020, Anonymous hacked the United Nations' website and created a page for Taiwan, a country which has not had a seat at the UN since 1971. The hacked page featured the Flag of Taiwan, the KMT emblem, a Taiwan Independence flag, and the Anonymous logo along with a caption. The hacked server belonged to the United Nations Department of Economic and Social Affairs.
In the wake of protests across the U.S. following the murder of George Floyd, Anonymous released a video on Facebook as well as sending it out to the Minneapolis Police Department on May 28, 2020, titled "Anonymous Message To The Minneapolis Police Department", in which they state that they are going to seek revenge on the Minneapolis Police Department, and "expose their crimes to the world". According to Bloomberg, the video was initially posted on an unconfirmed Anonymous Facebook page on May 28. According to BBC News, that same Facebook page had no notoriety and published videos of dubious content linked to UFOs and "China's plan to take over the world". It gained repercussions after the video about George Floyd was published and the Minneapolis police website, which is responsible for the police officer, was down. Later, Minnesota Governor Tim Walz said that every computer in the region suffered a sophisticated attack. According to BBC News, the attack on the police website using DDoS (Distributed Denial of Service) was unsophisticated. According to researcher Troy Hunt, these breaches of the site may have happened from old credentials. Regarding unverified Twitter posts that also went viral, where radio stations of police officers playing music and preventing communication are shown, experts point out that this is unlikely to be due to a hack attackif they are real. Later, it was confirmed by CNET that the leaks made from the police website are false and that someone is taking advantage of the repercussions of George Floyd's murder to spread misinformation.
On June 19, 2020, Anonymous published BlueLeaks, sometimes referred to by the Twitter hashtag #BlueLeaks, 269.21 gigabytes of internal U.S. law enforcement data through the activist group Distributed Denial of Secrets, which called it the "largest published hack of American law enforcement agencies". The data — internal intelligence, bulletins, emails, and reports — was produced between August 1996 and June 2020 by more than 200 law enforcement agencies, which provided it to fusion centers. It was obtained through a security breach of Netsential, a web developer that works with fusion centers and law enforcement. In Maine, legislators took interest in BlueLeaks thanks to details about the Maine Information and Analysis Center, which is under investigation. The leaks showed the fusion center was spying on and keeping records on people who had been legally protesting or had been "suspicious" but committed no crime.
In 2020, Anonymous started cyber-attacks against the Nigerian government. They started the operation to support the #EndSARS movement in Nigeria. The group's attacks were tweeted by a member of Anonymous called LiteMods. The websites of EFCC, INEC and various other Nigerian government websites were taken-down with DDoS attacks. The websites of some banks were compromised.
2021
The Texas Heartbeat Act, a law which bans abortions after six weeks of pregnancy, came into effect in Texas on September 1, 2021. The law relies on private citizens to file civil lawsuits against anyone who performs or induces an abortion, or aids and abets one, once "cardiac activity" in an embryo can be detected via transvaginal ultrasound, which is usually possible beginning at around six weeks of pregnancy. Shortly after the law came into effect, anti-abortion organizations set up websites to collect "whistleblower" reports of suspected violators of the bill.
On September 3, Anonymous announced "Operation Jane", a campaign focused on stymying those who attempted to enforce the law by "exhaust[ing] the investigational resources of bounty hunters, their snitch sites, and online gathering spaces until no one is able to maintain data integrity". On September 11, the group hacked the website of the Republican Party of Texas, replacing it with text about Anonymous, an invitation to join Operation Jane, and a Planned Parenthood donation link.
On September 13, Anonymous released a large quantity of private data belonging to Epik, a domain registrar and web hosting company known for providing services to websites that host far-right, neo-Nazi, and other extremist content. Epik had briefly provided services to an abortion "whistleblower" website run by the anti-abortion Texas Right to Life organization, but the reporting form went offline on September 4 after Epik told the group they had violated their terms of service by collecting private information about third parties. The data included domain purchase and transfer details, account credentials and logins, payment history, employee emails, and unidentified private keys. The hackers claimed they had obtained "a decade's worth of data" which included all customers and all domains ever hosted or registered through the company, and which included poorly encrypted passwords and other sensitive data stored in plaintext. Later on September 13, the Distributed Denial of Secrets (DDoSecrets) organization said they were working to curate the allegedly leaked data for more accessible download, and said that it consisted of "180gigabytes of user, registration, forwarding and other information". Publications including The Daily Dot and The Record by Recorded Future subsequently confirmed the veracity of the hack and the types of data that had been exposed. Anonymous released another leak on September 29, this time publishing bootable disk images of Epik's servers; more disk images as well as some leaked documents from the Republican Party of Texas appeared on October 4.
2022
On February 25, 2022, Twitter accounts associated with Anonymous declared that they had launched a 'cyber operations' against the Russian Federation, in retaliation for the invasion of Ukraine ordered by Russian president Vladimir Putin. The group later temporarily disabled websites such as RT.com and the website of the Defence Ministry along with other state owned websites. Anonymous also leaked 200 GB worth of emails from the Belarusian weapons manufacturer Tetraedr, which provided logistical support for Russia in the Russian invasion of Ukraine. Anonymous also hacked into Russian TV channels and played Ukrainian music through them and showed uncensored news of events in Ukraine.
Operation Russia
On March 7, 2022, Anonymous actors DepaixPorteur and TheWarriorPoetz declared on Twitter that they hacked 400 Russian surveillance cameras and broadcast them on a website. They call this operation "Russian Camera Dump".
Between March 25, 2022, and June 1, 2022, DDoSecrets collected hundreds and hundreds of gigabytes and millions of emails allegedly from the Central Bank of Russia, Capital Legal Services, All-Russia State Television and Radio Broadcasting Company (VGTRK), Aerogas, Blagoveshchensk City Administration, Continent Express, Gazregion, GUOV i GS - General Dept. of Troops and Civil Construction, Accent Capital, ALET/АЛЕТ, CorpMSP, Nikolai M. Knipovich Polar Research Institute of Marine Fisheries and Oceanography (PINRO), the Achinsk City Government, SOCAR Energoresource, Metprom Group LLC, and the Vyberi Radio / Выбери Радио group, all of which were allegedly hacked by Anonymous and Anonymous aligned NB65.
Iranian protests
On September 18, 2022, YourAnonSpider hacked the Supreme Leader of the Islamic Revolution of Iran's official webpage belonging to Ali Khamenei in retaliation to the death of Mahsa Amini. Anonymous launched a cyber operation against the Iranian government for the alleged murder of Mahsa Amini. Anonymous launched distributed denial of service (DDOS) attacks against Iran's government and state-owned websites. On September 23, 2022, a hacktivist named "Edaalate Ali" hacked Iran's state TV government channel during the middle of broadcast and released CCTV footage of Iran's prison facilities. On October 23, 2022, an Iranian hacker group known as "Black Reward" published confidential files and documents email system belonging to Iran's nuclear program. Black Reward announced on their Telegram channel that they have hacked into 324 emails which contained more than a hundred thousand messages and over 50 gigabytes of files. A hacktivist group by the name "Lab Dookhtegan" published the Microsoft Excel macros, PowerShell exploits APT34 reportedly used to target organizations across the world.
Chinese protests
In response to the 2022 COVID-19 protests in China, "Anonymous OpIran" launched Operation White Paper, attacked and took down Chinese government controlled websites, and leaked some Chinese government officials' personal information.
Related groups
LulzSec
In May 2011, the small group of Anons behind the HBGary Federal hack—including Tflow, Topiary, Sabu, and Kayla—formed the hacker group "Lulz Security", commonly abbreviated "LulzSec". The group's first attack was against Fox.com, leaking several passwords, LinkedIn profiles, and the names of 73,000 X Factor contestants. In May 2011, members of Lulz Security gained international attention for hacking into the American Public Broadcasting Service (PBS) website. They stole user data and posted a fake story on the site that claimed that rappers Tupac Shakur and Biggie Smalls were still alive and living in New Zealand. LulzSec stated that some of its hacks, including its attack on PBS, were motivated by a desire to defend WikiLeaks and its informant Chelsea Manning.
In June 2011, members of the group claimed responsibility for an attack against Sony Pictures that took data that included "names, passwords, e-mail addresses, home addresses and dates of birth for thousands of people." In early June, LulzSec hacked into and stole user information from the pornography website www.pron.com. They obtained and published around 26,000 e-mail addresses and passwords.
On June 14, 2011, LulzSec took down four websites by request of fans as part of their "Titanic Take-down Tuesday". These websites were Minecraft, League of Legends, The Escapist, and IT security company FinFisher. They also attacked the login servers of the multiplayer online game EVE Online, which also disabled the game's front-facing website, and the League of Legends login servers. Most of the takedowns were performed with DDoS attacks.
LulzSec also hacked a variety of government-affiliated sites, such as chapter sites of InfraGard, a non-profit organization affiliated with the FBI. The group leaked some of InfraGard member e-mails and a database of local users. On June 13, LulzSec released the e-mails and passwords of a number of users of senate.gov, the website of the U.S. Senate.
On June 15, LulzSec launched an attack on cia.gov, the public website of the U.S. Central Intelligence Agency, taking the website offline for several hours with a distributed denial-of-service attack. On December 2, an offshoot of LulzSec calling itself LulzSec Portugal attacked several sites related to the government of Portugal. The websites for the Bank of Portugal, the Assembly of the Republic, and the Ministry of Economy, Innovation and Development all became unavailable for a few hours.
On June 26, 2011, the core LulzSec group announced it had reached the end of its "50 days of lulz" and was ceasing operations. Sabu, however, had already been secretly arrested on June 7 and then released to work as an FBI informant. His cooperation led to the arrests of Ryan Cleary, James Jeffery, and others. Tflow was arrested on July 19, 2011, Topiary was arrested on July 27, and Kayla was arrested on March 6, 2012. Topiary, Kayla, Tflow, and Cleary pleaded guilty in April 2013 and were scheduled to be sentenced in May 2013. In April 2013, Australian police arrested the alleged LulzSec leader Aush0k, but subsequent prosecutions failed to establish police claims.
AntiSec
Beginning in June 2011, hackers from Anonymous and LulzSec collaborated on a series of cyber attacks known as "Operation AntiSec". On June 23, in retaliation for the passage of the immigration enforcement bill Arizona SB 1070, LulzSec released a cache of documents from the Arizona Department of Public Safety, including the personal information and home addresses of many law enforcement officers. On June 22, LulzSec Brazil took down the websites of the Government of Brazil and the President of Brazil. Later data dumps included the names, addresses, phone numbers, Internet passwords, and Social Security numbers of police officers in Arizona, Missouri, and Alabama. AntiSec members also stole police officer credit card information to make donations to various causes.
On July 18, LulzSec hacked into and vandalized the website of British newspaper The Sun in response to a phone-hacking scandal. Other targets of AntiSec actions have included FBI contractor ManTech International, computer security firm Vanguard Defense Industries, and defense contractor Booz Allen Hamilton, releasing 90,000 military e-mail accounts and their passwords from the latter.
In December 2011, AntiSec member "sup_g" (alleged by the U.S. government to be Jeremy Hammond) and others hacked Stratfor, a U.S.-based intelligence company, vandalizing its web page and publishing 30,000 credit card numbers from its databases. AntiSec later released millions of the company's e-mails to Wikileaks.
See also
Memetic persona
Luther Blissett (nom de plume)
Crowd psychology
John Doe
Proteus effect
Composition
Emergent organization
Fourth-generation warfare
Self-organization
Spontaneous order
Adhocracy
Activism
Electronic civil disobedience
Leaderless resistance
Streisand effect
Other related articles
Anti-mask laws
Derp (hacker group)
LulzRaft
Securax
RedHack
We Are Legion: The Story of the Hacktivists
References
Notes
Citations
Bibliography
External links
4chan
Anonymity pseudonyms
Anonymity
Anti-cult organizations
Articles containing video clips
Cyberattack gangs
Cyberattacks
Cybercrime in the United States
Hacker groups
Hacking in the 2000s
Hacking in the 2010s
Hacking in the 2020s
Hacktivists
Information society
Intellectual property activism
Internet culture
Internet memes
Internet trolling
Internet vigilantism
Internet-based activism
Organizations established in 2003
Political masks | Anonymous (hacker group) | Technology | 10,490 |
27,723,977 | https://en.wikipedia.org/wiki/Helix%20Producer%201 | Helix Producer I is a ship-shaped monohull floating production and offloading vessel, converted from the ferry MV Karl Carstens. It has no storage capability.
MV Karl Carstens
The ship was built in 1986 for Deutsche Bundesbahn as a roll-on roll-off (RORO) ferry serving on the Vogelfluglinie, a connection between Fehmarn, Germany and Denmark. It remained in service from 1986 until 1997.
Helix Producer I
The ship was reconfigured as a Floating Production vessel and converted between 2006–2008 at the Viktor Lenac Shipyard in Croatia. Topside production facilities were designed by OFD Engineering in Houston, Texas and installed in 2009 at the Kiewit shipyard in Corpus Christi, Texas, United States.
Helix Producer I has a Disconectable Transfer system (DTS) designed and supplied by Flexible Engineered Solutions LTD (FES), UK, and consists of a riser buoy supporting sub-sea risers and control umbilicals that would be connected to a deep water well and can be released from the hull, allowing the vessel to move out of the way of an approaching hurricane. After the storm, the vessel would return to the site and reconnect the buoy resuming normal oil extraction. It is operated by the Helix Energy Solutions Group and was scheduled to operate on the Phoenix Oil Field in the Gulf of Mexico, but on 14 June 2010 Helix announced that the ship would be directed to assist BP at the Deepwater Horizon oil spill site.
In its new configuration the ship has a length of , a breadth of (increased from before ), a depth of , and a draft of . The vessel has a maximum displacement of , and as a light ship of .
Service at Deepwater Horizon site
In June 2010, BP announced that Helix Producer I would join Discoverer Enterprise and Toisa Pisces at the Deepwater Horizon site to process oil that is flowing from the deepwater well. While Discover Enterprise can process about 18,000 barrels (760,000 US gallons; 2,900 cubic metres) of oil per day, Helix Producer I can handle about 30,000 barrels. The estimate of the uncontrolled oil flow at that time was up to 60,000 barrels. It was anticipated that Helix Producer I would be used for 2 months for this mission. Oil from Helix Producer I was to be offloaded by a shuttle tanker.
Starting in early August mud, later cement was pumped into the well, eventually closing it, so that by 19 September 2010, it could be announced that the Macondo Well had been finally killed.
References
1986 ships
Floating production storage and offloading vessels
Ships built in Kiel
Merchant ships of the Bahamas
Deepwater Horizon oil spill | Helix Producer 1 | Chemistry | 554 |
48,420,059 | https://en.wikipedia.org/wiki/Dilatancy%20%28granular%20material%29 | In soil mechanics, dilatancy or shear dilatancy is the volume change observed in granular materials when they are subjected to shear deformations. This effect was first described scientifically by Osborne Reynolds in 1885/1886 and is also known as Reynolds dilatancy. It was brought into the field of geotechnical engineering by .
Unlike most other solid materials, the tendency of a compacted dense granular material is to dilate (expand in volume) as it is sheared. This occurs because the grains in a compacted state are interlocking and therefore do not have the freedom to move around one another. When stressed, a lever motion occurs between neighboring grains, which produces a bulk expansion of the material. On the other hand, when a granular material starts in a very loose state it may continuously compact instead of dilating under shear. A sample of a material is called dilative if its volume increases with increasing shear and contractive if the volume decreases with increasing shear.
Dilatancy is a common feature of soils and sands. Its effect can be seen when the wet sand around the foot of a person walking on beach appears to dry up. The deformation caused by the foot expands the sand under it and the water in the sand moves to fill the new space between the grains.
Phenomenon
The phenomenon of dilatancy can be observed in a drained simple shear test on a sample of dense sand. In the initial stage of deformation, the volumetric strain decreases as the shear strain increases. But as the stress approaches its peak value, the volumetric strain starts to increase. After some more shear, the soil sample has a larger volume than when the test was started.
The amount of dilation depends strongly on the initial density of the soil. In general, the denser the soil, the greater the amount of volume expansion under shear. It has also been observed that the angle of internal friction decreases as the effective normal stress is decreased.
The relationship between dilation and internal friction is typically illustrated by the sawtooth model of dilatancy where the angle of dilation is analogous to the angle made by the teeth to the horizontal. Such a model can be used to infer that the observed friction angle is equal to the dilation angle plus the friction angle for zero dilation.
Why is dilatancy important?
Because of dilatancy, the angle of friction increases as the confinement increases until it reaches a peak value. After the peak strength of the soil is mobilized the angle of friction abruptly decreases. As a result, geotechnical engineering of slopes, footings, tunnels, and piles in such soils have to consider the potential decrease in strength after the soil strength reaches this peak value.
Poorly / uniformly graded silt with trace sand to sandy that is non-plastic can be associated with challenges during construction, even when they are hard. These materials often appear to be granular because the silt is so coarse and thus may be described as dense to very dense.
Vertical excavations below the water table in these soil types exhibit short term stability, similar to many dense sandy soil deposits, in part due to matric suction.
However, as shearing of the soil occurs in the active wedge due to gravity forces, strength is lost and the rate of failure accelerates. This can be exacerbated by hydrostatic forces developing at the location(s) where water (drains to and) collects in tension cracks in or near the back of the active wedge. Generally retrogressive spalling manifests, often accompanied by piping / internal erosion.
The use of appropriate filters is critical to managing these materials; a preferred filter might be a #4 sized clear gravel / coarse-grained sand as a commercial aggregate which is generally readily available. Some non- woven filter fabrics are also suitable. As with all filters, D15 and D50 compatibility criteria should be checked.
Dilatancy cut-off
After extensive shearing, dilating materials arrive in a state of critical density where dilatancy has come to an end. This phenomenon of soil behaviour can be included in the Hardening Soil model by means of a dilatancy cut-off. In order to specify this behaviour, the initial void ratio, , and the maximum void ratio, , of the material must be entered as general parameters. As soon as the volume change results in a state of maximum void, the mobilised dilatancy angle, , is automatically set back to zero.
See also
Triaxial shear tests
μ(I) rheology: one model of the rheology of a granular flow.
References
Soil mechanics | Dilatancy (granular material) | Physics | 933 |
31,999,888 | https://en.wikipedia.org/wiki/Coorbit%20theory | In mathematics, coorbit theory was developed by Hans Georg Feichtinger and Karlheinz Gröchenig around 1990. It provides theory for atomic decomposition of a range of Banach spaces of distributions. Among others the well established wavelet transform and the short-time Fourier transform are covered by the theory.
The starting point is a square integrable representation of a locally compact group on a Hilbert space , with which one can define a transform of a function with respect to by . Many important transforms are special cases of the transform, e.g. the short-time Fourier transform and the wavelet transform for the Heisenberg group and the affine group respectively. Representation theory yields the reproducing formula . By discretization of this continuous convolution integral it can be shown that by sufficiently dense sampling in phase space the corresponding functions will span a frame for the Hilbert space.
An important aspect of the theory is the derivation of atomic decompositions for Banach spaces. One of the key steps is to define the voice transform for distributions in a natural way. For a given Banach space , the corresponding coorbit space is defined as the set of all distributions such that . The reproducing formula is true also in this case and therefore it is possible to obtain atomic decompositions for coorbit spaces.
References
Hilbert spaces | Coorbit theory | Physics | 274 |
69,049,623 | https://en.wikipedia.org/wiki/Obesity%20and%20sexuality | Being overweight or obese has influence on the sexuality of people in various different aspects. It can include negative aspects such as stigmatization which can be an obstacle for romantic developments, sexual dysfunction and an increased chance of risky sexual behavior. It can also have positive aspects in the form of fat fetishism.
Background
The number of people with obesity has greatly increased in recent decades.
Childhood and puberty
Childhood obesity is correlated to early puberty. Girls who go through puberty earlier are more likely to be sexually active than other girls of the same age and are more likely to become pregnant and contract STDs. In their teen years, increased weight can also lead to obstacles for romantic developments. A 2005 study showed that "a teenage girl’s odds for a romantic relationship… dropped 6 to 7 percent for every 1-point increase in her body mass index." Gay, bisexual and transgender children are more likely to be obese, according to a 2020 study. The root cause for this is unknown.
Stigma
Being obese or overweight is stigmatized. In 2007, Substantia Jones started The Adipositivity Project, which is an annual nude photography series depicting fat couples in a positive way to reduce the stigma.
Dating and relationships
For many, the stigma in dating remains even after having lost weight, also due to fear of gaining weight again. According to psychology professor David Sarwer, the prevailing belief is that people who have never been obese are better able to control their weight. Sex educator Laura Delarato noted that there is fetishization of fat bodies. Some dating sites exclusively for fat people have been made. BMI is highly correlated between romantic partners.
Sexual health and satisfaction
An increased body weight can lead to an increase in sex hormone-binding globulin, which causes testosterone to fail. That can cause the libido to decrease. It can also narrow down the blood vessels, which makes it harder to climax. Sex positions tend to be more limited.
Men
In men, it can lead to erectile dysfunction.
Women
Women in class 3 obesity experience the most impairment in sexual quality of life, with an overall lack of enjoyment of sexual activity. In women, it generally leads to low self-esteem and negative self image.
Fat fetishism
Fat fetishism (and "feederism") has been described as a sexual subculture, sexual fetish and a lifestyle.
Hanne Blank has written:"Feederism is a red herring, it creates alarm and controversy that derails more meaningful discourse about fat sexuality. All of fat people’s sexuality gets lost in the shadow of the mainstream media’s voyeuristic fixation on what is portrayed as a freak show."
Some people consider feederism to be a part of BDSM, because food is used as a means of control because the feeder decides what the feedee eats and how much their body changes. Some fat people do happily engage in the fetishism and find fulfillment in it. Many have felt fetishism thrust on them without consent. Aubrey Gordon has rejected the notion that fat attraction is necessarily a fetish. Feederism has been depicted in films like Feed and City Island, where the first was not consensual but the latter was.
Pornography and sex work
Web queries on Internet pornography websites for 'fat' outpaced 'skinny'. As a 33 stone woman, Amanda Faye has been able to make a living out of eating for the camera.
Leblouh
Leblouh is the practice of force-feeding women.
References
Further reading
External links
Oversized? Here's your guide to sexual bliss
Can Three Obese Singletons Find Love? (Obese Dating Documentary) | Too Fat for Love | Only Human
Meet Gainer Bull, the 500lb erotic weight gainer eating 10k calories a day to please his OnlyFans followers
These men are sexually aroused from overfeeding their partners
Obesity
Sexology
Social stigma | Obesity and sexuality | Biology | 803 |
14,657,447 | https://en.wikipedia.org/wiki/Spectrochemistry | Spectrochemistry is the application of spectroscopy in several fields of chemistry. It includes analysis of spectra in chemical terms, and use of spectra to derive the structure of chemical compounds, and also to qualitatively and quantitively analyze their presence in the sample. It is a method of chemical analysis that relies on the measurement of wavelengths and intensity of electromagnetic radiation.
History
It was not until 1666 that Isaac Newton showed that white lights from the sun could be dissipated into a continuous series of colors. So Newton introduced the concept which he called spectrum to describe this phenomenon. He used a small aperture to define the beam of light, a lens to collimate it, a glass prism to disperse it, and a screen to display the resulting spectrum. Newton's analysis of light was the beginning of the science of spectroscopy. Later, It became clear that the Sun's radiation might have components outside the visible portion of the spectrum. In 1800 William Hershel showed that the sun's radiation extended into infrared, and in 1801 John Wilhelm Ritter also made a similar observation in the ultraviolet. Joseph Von Fraunhofer extended Newton's discovery by observing the sun's spectrum when sufficiently dispersed was blocked by a fine dark lines now known as Fraunhofer lines. Fraunhofer also developed diffracting grating, which disperses the lights in much the same way as does a glass prism but with some advantages. the grating applied interference of lights to produce diffraction provides a direct measuring of wavelengths of diffracted beams. So by extending Thomas Young's study which demonstrated that a light beam passes slit emerges in patterns of light and dark edges Fraunhofer was able to directly measure the wavelengths of spectral lines. However, despite his enormous achievements, Fraunhofer was unable to understand the origins of the special line in which he observed. It was not until 33 years after his passing that Gustav Kirchhoff established that each element and compound has its unique spectrum and that by studying the spectrum of an unknown source, one could determine its chemical compositions, and with these advancements, spectroscopy became a truly scientific method of analyzing the structures of chemical compounds. Therefore, by recognizing that each atom and molecule has its spectrum Kirchhoff and Robert Bunsen established spectroscopy as a scientific tool for probing atomic and molecular structures and founded the field of spectrochemical analysis for analyzing the composition of materials.
IR Spectra Tables & Charts
IR Spectrum Table by Frequency
IR Spectra Table by Compound Class
To use an IR spectrum table, first need to find the frequency or compound in the first column, depending on which type of chart that is being used. Then find the corresponding values for absorption, appearance and other attributes. The value for absorption is usually in cm−1.
NOTE: NOT ALL FREQUENCIES HAVE A RELATED COMPOUND.
Applications
Evaluation of Dual - Spectrum IR Spectrogram System on Invasive Ductal Carcinoma (IDC) Breast cancer
Invasive Ductal Carcinoma (IDC) is one of the common types of breast cancer which accounts for 8 out of 10 of all invasive breast cancers. According to the American Cancer Society, more than 180,000 women in the United States find out that they have breast cancers each year, and most are diagnosed with this specific type of cancer. While it is essential to detect breast cancer early to reduce the death rate there may be already more than 10,000,000 cells in breast cancer when it can be observed by x-ray mammograms. however, the IR Spectrum proposed by Szu et al seems to be more promising in detecting breast cancer cells several months ahead of a mammogram. Clinical tests have been carried out with approval of Institutional Review Board of National Taiwan University Hospital. So from August 2007 to June 2008 35 patients aged between (30-66) with an average age of 49 were enlisted in this project. the results established that about 63% of the success rate could be achieved with the cross-sectional data. Therefore the results concluded that breast cancers may be detected more accurately by cross-referencing S1 maps of multiple three-points.
Molecular spectroscopic Methods to Elucidation of Lignin Structure
A Ligninin plant cell is a complex amorphous polymer and it is biosynthesized from three aromatic alcohols, namely P-Coumaryl, Coniferyl, and Sinapyl alcohols. Lignin is a highly branched polymer and accounts for 15-30% by weight of lignocellulosic biomass (LCBM), so the structure of lignin will vary significantly according to the type of LCBM and the composition will depend on the degradation process. This biosynthesis process is mainly consists of radical coupling reactions and it generates a particular lignin polymer in each plant species. So due to having a complex structure, various molecular spectroscopic methods have been applied to resolve the aromatic units and different interunit linkages in lignin from distinct plant species.
References
Spectroscopy | Spectrochemistry | Physics,Chemistry | 1,014 |
14,440,888 | https://en.wikipedia.org/wiki/GPR101 | Probable G-protein coupled receptor 101 is a protein that is encoded by the GPR101 gene in humans.
G protein-coupled receptors (GPCRs, or GPRs) contain 7 transmembrane domains and transduce extracellular signals through heterotrimeric G proteins.
Clinical significance
A duplication event in GPR101 is implicated in cases of gigantism and acromegaly.
References
Further reading
G protein-coupled receptors | GPR101 | Chemistry | 94 |
52,733,664 | https://en.wikipedia.org/wiki/Levoketoconazole | Levoketoconazole, sold under the brand name Recorlev, is a steroidogenesis inhibitor that is used for the treatment of Cushing's syndrome. Levoketoconazole was approved for medical use in the United States in December 2021.
Levoketoconazole is the levorotatory or (2S,4R) enantiomer of ketoconazole, and it is an inhibitor of the enzymes CYP11B1 (11β-hydroxylase), CYP17A1 (17α-hydroxylase/17,20-lyase), and CYP21A2 (21-hydroxylase). It inhibits glucocorticoid biosynthesis and hence circulating levels of glucocorticoids, thereby treating Cushing's syndrome. In addition to its increased potency, the drug is 12-fold less potent than racemic ketoconazole in inhibiting CYP7A1 (cholesterol 7α-hydroxylase), theoretically resulting in further reduced interference with bile acid production and metabolite elimination and therefore less risk of hepatotoxicity. Levoketoconazole has also been found to inhibit CYP11A1 (cholesterol side-chain cleavage enzyme) and CYP51A1 (lanosterol-14α-demethylase), similarly but more potently relative to ketoconazole.
Research
In a systematic review of levoketoconazole, published in 2024, it was found to be effective in the management of Cushing Syndrome.
References
External links
7α-Hydroxylase inhibitors
11β-Hydroxylase inhibitors
21-Hydroxylase inhibitors
Acetamides
Antiglucocorticoids
Chloroarenes
Cholesterol side-chain cleavage enzyme inhibitors
CYP3A4 inhibitors
CYP17A1 inhibitors
Dioxolanes
Enantiopure drugs
Lanosterol 14α-demethylase inhibitors
Piperazines
Phenylethanolamine ethers | Levoketoconazole | Chemistry | 430 |
78,701,485 | https://en.wikipedia.org/wiki/Dina%20Triyoso | Dina H. Triyoso is an American materials scientist, and an expert on high-κ dielectrics and their applications in semiconductor-based electronics, and more generally on materials and processes for electronic devices. She works for Tokyo Electron (TEL), in New York.
Triyoso was a student of chemical engineering at Texas A&M University, where she received her Ph.D. in 2000, advised by Cellular engineer Theresa Good. She worked for Motorola Semiconductor Products and its spin-off Freescale Semiconductor, and then for GlobalFoundries, before taking her present position at Tokyo Electron in 2019.
She was named to the 2025 class of IEEE Fellows "for contributions to high-k metal gate complementary metal-oxide-semiconductor technology".
References
External links
Year of birth missing (living people)
Living people
American materials scientists
Women materials scientists and engineers
Texas A&M University alumni
Fellows of the IEEE | Dina Triyoso | Materials_science,Technology | 187 |
5,903,241 | https://en.wikipedia.org/wiki/SIGSAM | SIGSAM is the ACM Special Interest Group on Symbolic and Algebraic Manipulation. It publishes the ACM Communications in Computer Algebra and often sponsors the International Symposium on Symbolic and Algebraic Computation (ISSAC).
External links
ACM Official SIGSAM web site
ISSAC 2009, Seoul, Korea
ISSAC 2008, ("RISC Linz"), Hagenberg, Austria
ISSAC 2007, Waterloo, Ontario
ISSAC 2006, Genoa
ISSAC 2005, Beijing
ISSAC 2004, Santander, Cantabria
ISSAC 2003, Philadelphia
ISSAC 2002, Lille
ISSAC 2001, London, Ontario
ISSAC 2000, St. Andrews
ISSAC 1999, Vancouver
ISSAC 1998, Rostock
ISSAC 1997, Maui
Association for Computing Machinery Special Interest Groups
Computer algebra systems | SIGSAM | Mathematics,Technology | 154 |
6,809,062 | https://en.wikipedia.org/wiki/Chemokinesis | Chemokinesis is chemically prompted kinesis, a motile response of unicellular prokaryotic or eukaryotic organisms to chemicals that cause the cell to make some kind of change in their migratory/swimming behaviour. Changes involve an increase or decrease of speed, alterations of amplitude or frequency of motile character, or direction of migration. However, in contrast to chemotaxis, chemokinesis has a random, non-vectorial moiety, in general.
Due to the random character, techniques dedicated to evaluate chemokinesis are partly different from methods used in chemotaxis research. One of the most valuable ways to measure chemokinesis is computer-assisted (see, e.g., Image J) checker-board analysis, which provides data about migration of identical cells, whereas, in Protozoa (e.g., Tetrahymena), techniques based on measurement of opalescence were also developed.
References
External links
Chemotaxis
Cell biology
Perception
Signal transduction | Chemokinesis | Chemistry,Biology | 216 |
17,560,201 | https://en.wikipedia.org/wiki/Ajmalan | Ajmalan is a parent hydride used in the IUPAC nomenclature of natural products and also in CAS nomenclature. It is a 20-carbon alkaloid with six rings and seven chiral centres.
The name is derived from ajmaline, an antiarrhythmic alkaloid isolated from the roots of Rauvolfia serpentina which is formally a dihydroxy-derivative of ajmalan. The –an ending indicates that ajmalan is partially saturated. Ajmaline itself is named after Hakim Ajmal Khan, a distinguished practitioner of the Unani school of traditional medicine in South Asia.
The absolute configuration of the seven chiral carbon atoms in ajmalan is defined by convention, as is the numbering system. The stereochemistry is the same as that in naturally occurring ajmaline, and corresponds to (2R,3S,5S,7S,15S,16R,20S) using conventional numbering.
Ajmalan can be systematically named as
or as
.
Note that the numbering of the atoms in the systematic names is different from the conventional numbering of ajmalan.
The ajmalan skeleton is similar to those of certain other alkaloids, and ajmalan could also be given the following semisystematic names:
(2β,5β,7β,16R,20β)-1-methyl-2,7-dihydro-5,16:7,17-dicyclocorynan;
(2β,7β,16R,20β)-1-methyl-2,7,19,20-tetrahydro-7,17-cyclosarpagan;
(2β,3α,7β,20β)-1-methyl-2,7,19,20-tetrahydro-3,4:7,17-dicyclo-22-norvobasan;
(2β,5β,7β,16R,20β)-1-methyl-2,7-dihydro-5,16:7,17-dicyclo-17-secoyohimban.
However, the relative complexity even of these names justifies the use of ajmalan as a defined parent hydride in alkaloid nomenclature.
References
Alkaloids found in Apocynaceae
Chemical nomenclature
Heterocyclic compounds with 6 rings | Ajmalan | Chemistry | 504 |
61,495,719 | https://en.wikipedia.org/wiki/C9H22NO2PS | {{DISPLAYTITLE:C9H22NO2PS}}
The molecular formula C9H22NO2PS (molar mass: 239.31 g/mol, exact mass: 239.1109 u) may refer to:
EA-2192
VM (nerve agent) | C9H22NO2PS | Chemistry | 63 |
3,464,754 | https://en.wikipedia.org/wiki/Unicomp | Unicomp GA LLC (formerly Unicomp, Inc.) is an American manufacturer of computer keyboards and keyboard accessories, based in Lexington, Kentucky. The company was founded in 1996 by ex-IBM and Lexmark employees. Unicomp is the current license holder and manufacturer of Model M keyboards using buckling spring key switches, the patents for which they purchased from Lexmark in 1996.
History
In 1996, Lexmark International was prepared to shut down their Lexington keyboard factory where they produced Model M buckling-spring keyboards. IBM, their principal customer and the Model Ms original designer and patent holder, had decided to remove the Model M from its product line in favor of cost-saving rubber-dome keyboards.
Rather than seeing its production come to an end, a group of former Lexmark and IBM employees purchased the license, tooling and design rights for buckling-spring technology, and, in April 1996, reestablished the business as Unicomp.
Since 1996, the tooling and molds that Unicomp had inherited from Lexmark began to wear out, leading to a gradual decline in build quality and finish. However, in 2020 Unicomp replaced its tooling leading to quality improvements. The company also began shipping new designs at this time.
Products
Unicomp's product line consists largely of modified designs based on late Model M keyboards produced by Lexmark:
Classic, (formerly called the Customizer) is similar to one of IBM's late Model M variants and is built on the same tooling. The only changes to the Classic compared to an original Model M are the logo, Windows keys, optional USB connectivity (as an alternative to PS/2), and the option for a black case with light gray or white keys (as an alternative to the classic "pearl" beige).
Classic Trackball, a Classic with a trackball and two mouse buttons right above the indicator lights. However, it is not currently being produced due to low demand.
PC 122, a 5250 122-key keyboard similar to the Classic, but with a rearranged layout and an extra set of function keys, and many keys moved to the left side of the keyboard, and the home key moved to the middle of the arrow keys.
Ultra Classic, (formerly called the SpaceSaver) is a lighter, more compact version of the Classic. An Apple keyboard variant for macOS computers is sold under its former name of SpaceSaver M.
EnduraPro, is an Ultra Classic, except with a TrackPoint nub and two mouse buttons at the bottom inspired by the ThinkPads keyboards.
New Model M, a full-sized keyboard resembling an up-sized version of the Ultra Classic design. There is also a variant for Apple macOS computers.
Mini M''', a TKL (tenkeyless) version of New Model M with the lock lights moved from their traditional location above the now-absent numeric keypad to the top edge of the board above the F9-F12 keys.
Unicomp also offers a repair service along with replacement and custom parts for virtually all Model M'' and similar keyboards made by IBM, Lexmark, Maxi Switch, and Unicomp.
Gallery
References
See also
Keyboard technology
List of mechanical keyboards
External links
– Interoperability problems with modern hardware.
Review that includes company information
Unicomp featured on NPR
Companies established in 1996
Computer peripheral companies
Companies based in Lexington, Kentucky
Computer keyboard companies
Computer companies of the United States
Computer hardware companies | Unicomp | Technology | 709 |
2,902,750 | https://en.wikipedia.org/wiki/51%20Aquarii | 51 Aquarii is a binary star system located around 410 light years away from the Sun in the equatorial constellation of Aquarius. 51 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.78. The system is moving further from the Earth with a heliocentric radial velocity of +6 km/s.
The dual nature of this system was discovered by S. W. Burnham in 1873
with a Alvan Clark refractor. The pair orbit each other with a period of 145 years and a large eccentricity of 0.7. The magnitude 6.45 primary, designated component A, is an A-type main sequence star with a stellar classification of A0 V. It has a high rate of rotation with a projected rotational velocity of 91 km/s. The secondary component has a matching class of A0 with a visual magnitude of 6.63. It has an effective temperature of 10,238 K.
References
External links
Image 51 Aquarii
A-type main-sequence stars
Binary stars
Aquarius (constellation)
Durchmusterung objects
Aquarii, 051
212404
110578
8533 | 51 Aquarii | Astronomy | 254 |
188,524 | https://en.wikipedia.org/wiki/Cytopathology | Cytopathology (from Greek , kytos, "a hollow"; , pathos, "fate, harm"; and , -logia) is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by George Nicolas Papanicolaou in 1928. Cytopathology is generally used on samples of free cells or tissue fragments, in contrast to histopathology, which studies whole tissues. Cytopathology is frequently, less precisely, called "cytology", which means "the study of cells".
Cytopathology is commonly used to investigate diseases involving a wide range of body sites, often to aid in the diagnosis of cancer but also in the diagnosis of some infectious diseases and other inflammatory conditions. For example, a common application of cytopathology is the Pap smear, a screening tool used to detect precancerous cervical lesions that may lead to cervical cancer.
Cytopathologic tests are sometimes called smear tests because the samples may be smeared across a glass microscope slide for subsequent staining and microscopic examination. However, cytology samples may be prepared in other ways, including cytocentrifugation. Different types of smear tests may also be used for cancer diagnosis. In this sense, it is termed a cytologic smear.
Cell collection
There are two methods of collecting cells for cytopathologic analysis: exfoliative cytology, and intervention cytology.
Exfoliative cytology
In this method, cells are collected after they have been either spontaneously shed by the body ("spontaneous exfoliation"), or manually scraped/brushed off of a surface in the body ("mechanical exfoliation"). An example of spontaneous exfoliation is when cells of the pleural cavity or peritoneal cavity are shed into the pleural or peritoneal fluid. This fluid can be collected via various methods for examination. Examples of mechanical exfoliation include Pap smears, where cells are scraped from the cervix with a cervical spatula, or bronchial brushings, where a bronchoscope is inserted into the trachea and used to evaluate a visible lesion by brushing cells from its surface and subjecting them to cytopathologic analysis.
Intervention cytology
In intervention cytology the pathologist intervenes into the body for sample collection.
Fine-needle aspiration
Fine-needle aspiration, or fine-needle aspiration cytology (FNAC), involves use of a needle attached to a syringe to collect cells from lesions or masses in various body organs by microcoring, often with the application of negative pressure (suction) to increase yield. FNAC can be performed under palpation guidance (i.e., the clinician can feel the lesion) on a mass in superficial regions like the neck, thyroid or breast; FNAC may be assisted by ultrasound or CAT scan for sampling of deep-seated lesions within the body that cannot be localized via palpation. FNAC is widely used in many countries, but success rate is dependent on the skill of the practitioner. If performed by a pathologist alone, or as team with pathologist-cytotechnologist, the success rate of proper diagnosis is higher than when performed by a non-pathologist. This may be due to the pathologist's ability to immediately evaluate specimens under a microscope and immediately repeat the procedure if sampling was inadequate.
Fine needles are 23 to 27 gauge. Because needles as small as 27 gauge can almost always yield diagnostic material, FNAC is often the least injurious way to obtain diagnostic tissue from a lesion. Sometimes a syringe holder may be used to facilitate using one hand to perform the biopsy while the other hand is immobilizing the mass. Imaging equipment such as a CT scanner or ultrasound may be used to assist in locating the region to be biopsied.
FNAC has become synonymous to interventional cytology.
Sediment cytology
For cytology of sediment, the sample is collected from the fixative that was used for processing the biopsy or autopsy specimen. The fixative is mixed properly and taken into a centrifuge tube and is centrifuged. The sediment is used for smearing. These sediments are the cells that are shed by the autopsy and biopsy specimen during processing.
Imprint cytology
Imprint cytology is a preparation wherein the tissue of interest touches a glass slide, leaving behind its imprint in the form of cells on the slide. The imprint can subsequently be stained and studied.
Preparation
After sampling, two main techniques for processing are used:
Smearing of sample directly onto a glass slide.
Liquid-based cytology. With the latter, the sample is placed in a liquid that is then processed for further investigation.
Processing of specimens may result in visual artifacts:
For better visualization of cells and their components, specimens are inked, such as by the Papanicolaou stain, or Romanowsky stain derivatives which include Giemsa, Jenner, Wright, Field, May–Grünwald and Leishman stains.
Parameters
The nucleus of the cell is very important in evaluating the cellular sample. In cancerous cells, altered DNA activity can be seen as a physical change in the nuclear qualities. Since more DNA is unfolded and being expressed, the nucleus will be darker and less uniform, larger than in normal cells, and often show a bright-red nucleolus.
While the cytologist's primary responsibility is to discern whether cancerous or precancerous pathology is present in the cellular sample analysed, other pathologies may be seen such as:
microbial infections: parasitic, viral, and/or bacterial
reactive changes
immune reactions
cell aging
amyloidosis
autoimmune diseases
Various normal functions of cell growth, metabolism, and division can fail or work in abnormal ways and lead to diseases.
Cytopathology is best used as one of three tools, the second and third being the physical examination and medical imaging. Cytology can be used to diagnose a condition and spare a patient from surgery to obtain a larger specimen. An example is thyroid FNAC; many benign conditions can be diagnosed with a superficial biopsy and the patient can go back to normal activities right away. If a malignant condition is diagnosed, the patient may be able to start radiation/chemotherapy, or may need to have surgery to remove and/or stage the cancer.
Some tumors may be difficult to biopsy, such as sarcomas. Other rare tumors may be dangerous to biopsy, such as pheochromocytoma. In general, a fine-needle aspiration can be done anywhere it is safe to put a needle, including liver, lung, kidney, and superficial masses.
Proper cytopathology technique takes time to master. Cytotechnologists and cytopathologists can assist clinicians by assisting with sample collection. A "quick read" is a peek under the microscope and can tell the clinician whether enough diagnostic material was obtained. Cytological specimens must be properly prepared so that the cells are not damaged.
Further information about the specimen may be gained by immunohistochemical stains and molecular testing, particularly if the sample is prepared using liquid based cytology. Often "reflex" testing is performed, such as HPV testing on an abnormal pap test or flow cytometry on a lymphoma specimen.
Body regions
Cytopathologic techniques are used in the examination of virtually all body organs and tissues:
Gynecologic cytology – concerning the female reproductive tract
Urinary tract cytology – concerning the ureters, urinary bladder and urethra. See Urine cytology.
Effusion cytology – concerning fluids collections, especially within the peritoneum, pleura and pericardium
Breast cytology – principally concerning the female breast
Vaginal cytology - principally concerning non-human mammals
Thyroid cytology – concerning the thyroid gland
Lymph node cytology – concerning lymph nodes
Respiratory cytology – concerning the lungs and airways
Gastrointestinal cytology – concerning the alimentary tract
Soft tissue, bone and skin cytology
Kidney and adrenal cytology
Liver and pancreas cytology
Central nervous system cytology
Eye cytology
Salivary gland cytology
See also
American Society of Cytopathology
Anatomical pathology
Cancer Cytopathology
Cell biology
Clinical pathology
Pleomorphism
Notes and references
External links
International Academy of Cytology
British Association for Cytopathology
Australian Society of Cytology
Papanicolaou Society of Cytopathology
E-Learning for Medical Students | cellnetpathology.com
www.ascp.org
asct.com (archived)
The International Academy of Cytology
Anatomical pathology
Cell biology
Diagnostic obstetrics and gynaecology
Infectious causes of cancer | Cytopathology | Biology | 1,817 |
8,649,736 | https://en.wikipedia.org/wiki/Varicella%20vaccine | Varicella vaccine, also known as chickenpox vaccine, is a vaccine that protects against chickenpox. One dose of vaccine prevents 95% of moderate disease and 100% of severe disease. Two doses of vaccine are more effective than one. If given to those who are not immune within five days of exposure to chickenpox it prevents most cases of the disease. Vaccinating a large portion of the population also protects those who are not vaccinated. It is given by injection just under the skin. Another vaccine, known as zoster vaccine, is used to prevent diseases caused by the same virus – the varicella zoster virus.
The World Health Organization (WHO) recommends routine vaccination only if a country can keep more than 80% of people vaccinated. If only 20% to 80% of people are vaccinated it is possible that more people will get the disease at an older age and outcomes overall may worsen. Either one or two doses of the vaccine are recommended. In the United States two doses are recommended starting at twelve to fifteen months of age. , twenty-three countries recommend all non-medically exempt children receive the vaccine, nine recommend it only for high-risk groups, three additional countries recommend use in only parts of the country, while other countries make no recommendation. Not all countries provide the vaccine due to its cost. In the United Kingdom, Varilrix, a live viral vaccine is approved from the age of 12 months, but only recommended for certain at risk groups.
Minor side effects may include pain at the site of injection, fever, and rash. Severe side effects are rare and occur mostly in those with poor immune function. Its use in people with HIV/AIDS should be done with care. It is not recommended during pregnancy; however, the few times it has been given during pregnancy no problems resulted. The vaccine is available either by itself or along with the MMR vaccine, in a version known as the MMRV vaccine. It is made from weakened virus.
A live attenuated varicella vaccine, the Oka strain, was developed by Michiaki Takahashi and his colleagues in Japan in the early 1970s. American vaccinologist Maurice Hilleman's team developed a chickenpox vaccine in the United States in 1981, based on the "Oka strain" of the varicella virus. The chickenpox vaccine first became commercially available in 1984. It is on the WHO Model List of Essential Medicines.
Medical uses
Varicella vaccine is 70% to 90% effective for preventing varicella and more than 95% effective for preventing severe varicella. Follow-up evaluations have taken place in the United States of children immunized that revealed protection for at least 11 years. Studies were conducted in Japan which indicated protection for at least 20 years.
People who do not develop enough protection when they get the vaccine may develop a mild case of the disease when in close contact with a person with chickenpox. In these cases, people show very little sign of illness. This has been the case of children who get the vaccine in their early childhood and later have contact with children with chickenpox. Some of these children may develop mild chickenpox also known as breakthrough disease.
Another vaccine, known as zoster vaccine, is simply a larger-than-normal dose of the same vaccine used against chickenpox and is used in older adults to reduce the risk of shingles (also called herpes zoster) and postherpetic neuralgia, which are caused by the same virus. The recombinant zoster (shingles) vaccine is recommended for adults aged 50 years and older.
Duration of immunity
The long-term duration of protection from varicella vaccine is unknown, but there are now persons vaccinated twenty years ago with no evidence of waning immunity, while others have become vulnerable in as few as six years. Assessments of the duration of immunity are complicated in an environment where natural disease is still common, which typically leads to an overestimation of effectiveness.
Some vaccinated children have been found to lose their protective antibodies in as little as five to eight years. However, according to the World Health Organization (WHO): "After observation of study populations for periods of up to 20 years in Japan and 10 years in the United States, more than 90% of immunocompetent persons who were vaccinated as children were still protected from varicella." However, since only one out of five Japanese children were vaccinated, the annual exposure of these vaccinees to children with natural chickenpox boosted the vaccinees' immune system. In the United States, where universal varicella vaccination has been practiced, the majority of children no longer receive exogenous (outside) boosting, thus, their cell-mediated immunity to VZV (varicella zoster virus) wanes – necessitating booster chickenpox vaccinations. As time goes on, boosters may be necessary. Persons exposed to the virus after vaccination tend to experience milder cases of chickenpox if they develop the disease.
Chickenpox
Prior to the widespread introduction of the vaccine in the United States in 1995 (1986 in Japan and 1988 in Korea), there were around 4,000,000 cases per year in the United States, mostly in children, with typically 10,500–13,000 hospital admissions (range, 8,000–18,000), and 100–150 deaths each year. Most of the deaths were among young children.
During 2003, and the first half of 2004, the CDC reported eight deaths from varicella, six of whom were children or adolescents. These deaths and hospital admissions have substantially declined in the US due to vaccination, though the rate of shingles infection has increased as adults are less exposed to infected children (which would otherwise help protect against shingles). Ten years after the vaccine was recommended in the US, the CDC reported as much as a 90% drop in chickenpox cases, a varicella-related hospital admission decline of 71% and a 97% drop in chickenpox deaths among those under 20.
Vaccines are less effective among high-risk patients, as well as being more dangerous because they contain attenuated live viruses. In a study performed on children with an impaired immune system, 30% had lost the antibody after five years, and 8% had already caught wild chickenpox in those five years.
Herpes zoster
Herpes zoster (shingles) most often occurs in the elderly and is only rarely seen in children. The incidence of herpes zoster in vaccinated adults is 0.9/1000 person-years, and is 0.33/1000 person-years in vaccinated children; this is lower than the overall incidence of 3.2–4.2/1000 person-years.
The risk of developing shingles is reduced for children who receive the varicella vaccine, but not eliminated. The CDC stated in 2014: "Chickenpox vaccines contain weakened live VZV, which may cause latent (dormant) infection. The vaccine-strain VZV can reactivate later in life and cause shingles. However, the risk of getting shingles from vaccine-strain VZV after chickenpox vaccination is much lower than getting shingles after natural infection with wild-type VZV."
The risk of shingles is significantly lower among children who have received varicella vaccination, including those who are immunocompromised. The risk of shingles is approximately 80% lower among healthy vaccinated children compared to unvaccinated children who had wild-type varicella. A population with high varicella vaccination also has lower incidence of shingles in unvaccinated children, due to herd immunity.
Schedule
The WHO recommends one or two doses with the initial dose given at 12 to 18 months of age. The second dose, if given, should occur at least one to three months later. The second dose, if given, provides the additional benefit of improved protection against all varicella. This vaccine is a shot given subcutaneously (under the skin). It is recommended for all children under 13 and for everyone 13 or older who has never had chickenpox.
In the United States, two doses are recommended by the CDC. For a routine vaccination, the first dose is administered at 12 to 15 months of age and the second dose at age 4–6 years. However, the second dose can be given as early as 3 months after the first dose. If an individual misses the timing for the routine vaccination, the individual is eligible to receive a catch-up vaccination. For a catch-up vaccination, individuals between 7 and 12 years old should receive a two-dose series 3 months apart (a minimum interval of 4 weeks). For individuals 13–18 years old, the catch-up vaccination should be given 4 to 8 weeks apart (a minimum interval of 4 weeks). The varicella vaccine did not become widely available in the United States until 1995.
In the UK, the vaccine is only available on the National Health Service for those who are in close contact with someone who is particularly vulnerable to chickenpox. As there is an increased risk of shingles in adults due to possible lack of contact with chickenpox-infected children providing a natural boosting to immunity, and the fact that chickenpox is usually a mild illness, the NHS cites concerns about unvaccinated children catching chickenpox as adults when it is more dangerous. However, the vaccine is approved for 12 months and up and is available privately, with a second dose to be given a year after the first.
Contraindications
The varicella vaccine is not recommended for seriously ill people, pregnant women, people who have tuberculosis, people who have experienced a serious allergic reaction to the varicella vaccine in the past, people who are allergic to gelatin, people allergic to neomycin, people receiving high doses of steroids, people receiving treatment for cancer with x-rays or chemotherapy, as well as people who have received blood products or transfusions during the past five months. Additionally, the varicella vaccine is not recommended for people who are taking salicylates (e.g. aspirin). After receiving the varicella vaccine, the use of salicylates should be avoided for at least six weeks. The varicella vaccine is also not recommended for individuals who have received a live vaccine in the last four weeks, because live vaccines that are administered too soon within one another may not be as effective. It may be usable in people with HIV infections who have a good blood count and are receiving appropriate treatment. Specific antiviral medication, such as acyclovir, famciclovir, or valacyclovir, are not recommended 24 hours before and 14 days after vaccination.
Side effects
Serious side effects are very rare. From 1998 to 2013, only one vaccine-related death was reported: an English child with pre-existent leukemia. On some occasions, severe reactions such as meningitis and pneumonia have been reported (mainly in inadvertently vaccinated immunocompromised children) as well as anaphylaxis.
The possible mild side effects include redness, stiffness, and soreness at the injection site, as well as fever. A few people may develop a mild rash, which usually appears around the injection site.
There is a short-term risk of developing herpes zoster (shingles) following vaccination. However, this risk is less than the risk due to a natural infection resulting in chickenpox. Most of the cases reported have been mild and have not been associated with serious complications.
Approximately 5% of children who receive the vaccine develop a fever or rash. Adverse reaction reports for the period 1995 to 2005 found no deaths attributed to the vaccine despite approximately 55.7 million doses being delivered. Cases of vaccine-related chickenpox have been reported in patients with a weakened immune system, but no deaths.
The literature contains several reports of adverse reactions following varicella vaccination, including vaccine-strain zoster in children and adults.
History
The varicella-zoster vaccine is made from the Oka/Merck strain of live attenuated varicella virus. The Oka virus was initially obtained from a child with natural varicella, introduced into human embryonic lung cell cultures, adapted to and propagated in embryonic guinea pig cell cultures, and finally propagated in a human diploid cell line originally derived from fetal tissues (WI-38). Takahashi and his colleagues used the Oka strain to develop a live attenuated varicella vaccine in Japan in the early 1970s. This strain was further developed by pharmaceutical companies such as Merck & Co. and GlaxoSmithKline. American vaccinologist Maurice Hilleman's team at Merck then used the Oka strain to prepare a chickenpox vaccine in 1981.
Japan was among the first countries to vaccinate for chickenpox. The vaccine developed by Hilleman was first licensed in the United States in 1995. Routine vaccination against varicella zoster virus is also performed in the United States, and the incidence of chickenpox has been dramatically reduced there (from four million cases per year in the pre-vaccine era to approximately 390,000 cases per year ).
, standalone varicella vaccines are available in all 27 European Union member countries, and 16 countries also offer a combined measles, mumps, rubella, and varicella vaccine (MMRV). Twelve European countries (Austria, Andorra, Cyprus, Czech Republic, Finland, Germany, Greece, Hungary, Italy, Latvia, Luxembourg and Spain) have universal varicella vaccination (UVV) policies, though only six of these countries have made it available at no cost via government funding. EU member states that have not implemented UVV cite reasons such as "a perceived low disease burden and low public health priority," the cost and cost-effectiveness, the possible risk of herpes zoster when vaccinating older adults, and rare fevers leading to seizures after the first dose of the MMRV vaccine. "Countries that implemented UVV experienced decreases in varicella incidence, hospitalizations, and complications, showing overall beneficial impact."
Varicella vaccination is recommended in Canada for all healthy children aged 1 to 12, as well as susceptible adolescents and adults 50 years of age and younger; "may be considered for people with select immunodeficiency disorders; and "should be prioritized" for susceptible individuals, including "non-pregnant women of childbearing age, household contacts of immunocompromised individuals, members of a household expecting a newborn, health care workers, adults who may be exposed occupationally to varicella (for example, people who work with young children), immigrants and refugees from tropical regions, people receiving chronic salicylate therapy (for example, acetylsalicylic acid [ASA])," and others.
Australia has adopted recommendations for routine immunization of children and susceptible adults against chickenpox.
Other countries, such as the United Kingdom, have targeted recommendations for the vaccine, e.g., for susceptible healthcare workers at risk of varicella exposure. In the UK, varicella antibodies are measured as part of the routine of prenatal care, and by 2005 all National Health Service personnel had determined their immunity and been immunized if they were non-immune and had direct patient contact. Population-based immunization against varicella is not otherwise practised in the UK.
Since 2013, the MMRV vaccine has been offered for free to all Brazilian citizens.
Society and culture
Catholic Church
The use of fetal tissue in vaccine development is the practice of researching, developing, and producing vaccines through growing viruses in cultured (laboratory-grown) cells that were originally derived from human fetal tissue. Since the cell strains in use originate from abortions, there has been some opposition to the practice and the resulting vaccines on religious and moral grounds.
The Roman Catholic Church is opposed to abortion. Nevertheless, the Pontifical Academy for Life stated in 2017 that "clinically recommended vaccinations can be used with a clear conscience and that the use of such vaccines does not signify some sort of cooperation with voluntary abortion". On 21 December 2020, the Vatican's doctrinal office, the Congregation for the Doctrine of the Faith, further clarified that it is "morally " for Catholics to receive vaccines derived from fetal cell lines or in which such lines were used in testing or development, because "passive material cooperation in the procured abortion from which these cell lines originate is, on the part of those making use of the resulting vaccines, remote" and "does not and should not in any way imply that there is a moral endorsement of the use of cell lines proceeding from aborted fetuses".
References
Further reading
`
External links
Chickenpox
Live vaccines
Vaccines
Drugs developed by Merck & Co.
World Health Organization essential medicines (vaccines)
Wikipedia medicine articles ready to translate
Japanese inventions | Varicella vaccine | Biology | 3,571 |
2,865,101 | https://en.wikipedia.org/wiki/Ischemic%20cascade | The ischemic (ischaemic) cascade is a series of biochemical reactions that are initiated in the brain and other aerobic tissues after seconds to minutes of ischemia (inadequate blood supply). This is typically secondary to stroke, injury, or cardiac arrest due to heart attack. Most ischemic neurons that die do so due to the activation of chemicals produced during and after ischemia. The ischemic cascade usually goes on for two to three hours but can last for days, even after normal blood flow returns.
Mechanism
A cascade is a series of events in which one event triggers the next, in a linear fashion. Thus "ischemic cascade" is actually a misnomer, since the events are not always linear: in some cases they are circular, and sometimes one event can cause or be caused by multiple events. In addition, cells receiving different amounts of blood may go through different chemical processes. Despite these facts, the ischemic cascade can be generally characterized as follows:
Low blood supply decreases amount of oxygen that reaches tissues, leading to hypoxia
Deficiency of oxygen causes the neuron's normal process for making ATP for energy to fail.
The cell switches to anaerobic metabolism, producing lactic acid.
ATP-reliant ion transport pumps fail, causing the cell to become depolarized, allowing ions, including calcium (Ca2+), to flow into the cell.
The ion pumps can no longer transport calcium out of the cell, and intracellular calcium levels get too high.
The presence of calcium triggers the release of the excitatory amino acid neurotransmitter glutamate.
Glutamate stimulates AMPA receptors and Ca2+-permeable NMDA receptors, which open to allow more calcium into cells.
Excess calcium entry overexcites cells and causes the generation of harmful chemicals like free radicals, reactive oxygen species and calcium-dependent enzymes such as calpain, endonucleases, ATPases, and phospholipases in a process called excitotoxicity. Calcium can also cause the release of more glutamate.
As the cell's membrane is broken down by phospholipases, it becomes more permeable, and more ions and harmful chemicals flow into the cell.
Mitochondria break down, releasing toxins and apoptotic factors into the cell.
The caspase-dependent apoptosis cascade is initiated, causing cells to "commit suicide."
If the cell dies through necrosis, it releases glutamate and toxic chemicals into the environment around it. Toxins poison nearby neurons, and glutamate can overexcite them.
If and when the brain is reperfused, a number of factors lead to reperfusion injury.
An inflammatory response is mounted, and phagocytic cells engulf damaged but still viable tissue.
Harmful chemicals damage the blood–brain barrier.
Cerebral edema (swelling of the brain) occurs due to leakage of large molecules like albumins from blood vessels through the damaged blood brain barrier. These large molecules pull water into the brain tissue after them by osmosis. This "vasogenic edema" causes compression of and damage to brain tissue (Freye 2011; Acquired Mitochondropathy-A New Paradigm in Western Medicine Explaining Chronic Diseases).
Mitigation of effects
The fact that the ischemic cascade involves a number of steps has led doctors to suspect that cerebroprotectants could be produced to interrupt the cascade at a single one of the steps, blocking the downstream effects. Over 150 cerebroprotectants have been tested in clinical trials, leading to the approval of tissue plasminogen activator (also known as tPA, t-PA, rtPA, Activase, or Alteplase or Actilyse) in the US and other countries, and edaravone (Radicut) in Japan.
References
Cascade
Angiology
Pathology | Ischemic cascade | Biology | 827 |
18,369,738 | https://en.wikipedia.org/wiki/Jacquemart%20%28bellstriker%29 | A jacquemart (sometimes jaquemart and also called a quarter-jack) is an automaton, an animated, mechanised figure of a person, usually made from wood or metal, which strikes the hours on a bell with a hammer. Jacquemarts are usually part of clocks or clocktowers, and are often near or at the top of the construction. The figurine is also known as Jack of the Clock or Jack o'Clock.
One of the oldest and best-known jacquemarts is found on the south tower of the cathedral Church of Notre Dame of Dijon: it was installed by Philippe II of Burgundy in 1383. Other well-known historic jacquemarts are found on top of the Zytglogge tower in Bern, Switzerland and the Moors on the Torre dell'Orlogio di San Marco in Venice, Italy.
The word is originally French but is sometimes used in English as well. The origin of the word is disputed, but one theory relates it to a tool called a 'jacke', used by the craftsmen building church towers, the steeplejacks.
In the South-West, the only existing one is that of Lavaur, located at the top of the bell tower of the Saint-Alain cathedral. Legend has it that during the wars of religion a Protestant prisoner was locked up in the bell tower and had to ring the bells every hour. He built a mechanism to do it for him.
Notable jacquemart figures
Wimborne Minster Astronomical Clock, Dorset
Norwich Cathedral astronomical clock, Norfolk
The Potts of Leeds Ivanhoe Clock figures of 1878 by John Wormald Appleyard in Thornton's Arcade, Leeds, West Yorkshire, England.
The coolie at Lau Pa Sat, Singapore
See also
Automaton clock
References
External links
Timekeeping components | Jacquemart (bellstriker) | Technology | 379 |
1,979,663 | https://en.wikipedia.org/wiki/Ring%20strain | In organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are substantially smaller than the idealized value of approximately 109°. Because of their high strain, the heat of combustion for these small rings is elevated.
Ring strain results from a combination of angle strain, conformational strain or Pitzer strain (torsional eclipsing interactions), and transannular strain, also known as van der Waals strain or Prelog strain. The simplest examples of angle strain are small cycloalkanes such as cyclopropane and cyclobutane.
Ring strain energy can be attributed to the energy required for the distortion of bond and bond angles in order to close a ring.
Ring strain energy is believed to be the cause of accelerated rates in altering ring reactions. Its interactions with traditional bond energies change the enthalpies of compounds effecting the kinetics and thermodynamics of ring strain reactions.
History
Ring strain theory was first developed by German chemist Adolf von Bayer in 1890. Previously, the only bonds believed to exist were torsional and steric; however, Bayer's theory became based on the interactions between the two strains.
Bayer's theory was based on the assumption that ringed compounds were flat. Later, around the same time, Hermann Sachse formed his postulation that compound rings were not flat and potentially existed in a "chair" formation. Ernst Mohr later combined the two theories to explain the stability of six-membered rings and their frequency in nature, as well as the energy levels of other ring structures.
Angle strain (Baeyer strain)
Alkanes
In alkanes, optimum overlap of atomic orbitals is achieved at 109.5°. The most common cyclic compounds have five or six carbons in their ring. Adolf von Baeyer received a Nobel Prize in 1905 for the discovery of the Baeyer strain theory, which was an explanation of the relative stabilities of cyclic molecules in 1885.
Angle strain occurs when bond angles deviate from the ideal bond angles to achieve maximum bond strength in a specific chemical conformation. Angle strain typically affects cyclic molecules, which lack the flexibility of acyclic molecules.
Angle strain destabilizes a molecule, as manifested in higher reactivity and elevated heat of combustion. Maximum bond strength results from effective overlap of atomic orbitals in a chemical bond. A quantitative measure for angle strain is strain energy. Angle strain and torsional strain combine to create ring strain that affects cyclic molecules.
Normalized energies that allow comparison of ring strains are obtained by measuring per methylene group (CH2) of the molar heat of combustion in the cycloalkanes.
combustion per CH2 − 658.6 kJ = strain per CH2
The value 658.6 kJ per mole is obtained from an unstrained long-chain alkane.
Cycloalkanes generally have less ring strain than cycloalkenes, which is seen when comparing cyclopropane and cyclopropene.
Angle strain in alkenes
Cyclic alkenes are subject to strain resulting from distortion of the sp2-hybridized carbon centers. Illustrative is C60 where the carbon centres are pyramidalized. This distortion enhances the reactivity of this molecule. Angle strain also is the basis of Bredt's rule which dictates that bridgehead carbon centers are not incorporated in alkenes because the resulting alkene would be subject to extreme angle strain.
Small trans-cycloalkenes have so much ring strain they cannot exist for extended periods of time. For instance, the smallest trans-cycloalkane that has been isolated is trans-cyclooctene. Trans-cycloheptene has been detected via spectrophotometry for minute time periods, and trans-cyclohexene is thought to be an intermediate in some reactions. No smaller trans-cycloalkenes are known. On the contrary, while small cis-cycloalkenes do have ring strain, they have much less ring strain than small trans-cycloalkenes.
In general, the increased levels of unsaturation in alkenes leads to higher ring strain. Increasing unsaturation leads to greater ring strain in cyclopropene. Therefore, cyclopropene is an alkene that has the most ring strain between the two mentioned. The differing hybridizations and geometries between cyclopropene and cyclopropane contribute to the increased ring strain. Cyclopropene also has an increased angle strain, which also contributes to the greater ring strain. However, this trend does not always work for every alkane and alkene.
Torsional strain (Pitzer strain)
In some molecules, torsional strain can contribute to ring strain in addition to angle strain. One example of such a molecule is cyclopropane. Cyclopropane's carbon-carbon bonds form angles of 60°, far from the preferred angle of 109.5° angle in alkanes, so angle strain contributes most to cyclopropane's ring strain. However, as shown in the Newman projection of the molecule, the hydrogen atoms are eclipsed, causing some torsional strain as well.
Examples
In cycloalkanes, each carbon is bonded nonpolar covalently to two carbons and two hydrogen. The carbons have sp3 hybridization and should have ideal bond angles of 109.5°. Due to the limitations of cyclic structure, however, the ideal angle is only achieved in a six carbon ring — cyclohexane in chair conformation. For other cycloalkanes, the bond angles deviate from ideal.
Molecules with a high amount of ring strain consist of three, four, and some five-membered rings, including: cyclopropanes, cyclopropenes, cyclobutanes, cyclobutenes, [1,1,1]propellanes, [2,2,2]propellanes, epoxides, aziridines, cyclopentenes, and norbornenes. These molecules have bond angles between ring atoms which are more acute than the optimal tetrahedral (109.5°) and trigonal planar (120°) bond angles required by their respective sp3 and sp2 bonds. Because of the smaller bond angles, the bonds have higher energy and adopt more p-character to reduce the energy of the bonds. In addition, the ring structures of cyclopropanes/enes and cyclclobutanes/enes offer very little conformational flexibility. Thus, the substituents of ring atoms exist in an eclipsed conformation in cyclopropanes and between gauche and eclipsed in cyclobutanes, contributing to higher ring strain energy in the form of van der Waals repulsion.
monocycles
cyclopropane (29 kcal/mol), C3H6 — the C-C-C bond angles are 60° whereas tetrahedral 109.5° bond angles are expected. The intense angle strain leads to nonlinear orbital overlap of its sp3 orbitals. Because of the bond's instability, cyclopropane is more reactive than other alkanes. Since any three points make a plane and cyclopropane has only three carbons, cyclopropane is planar. The H-C-H bond angle is 115° whereas 106° is expected as in the CH2 groups of propane.
cyclobutane (26.3 kcal/mol), C4H8 — if cyclobutane were completely square planar, its bond angles would be 90° whereas tetrahedral 109.5° bond angles are expected. However, the actual C-C-C bond angle is 88° because it has a slightly folded form to relieve some torsional strain at the expense of slightly more angle strain. The high strain energy of cyclobutane is primarily from angle strain.
cyclopentane (7.4 kcal/mol), C5H10 — if it was a completely regular planar pentagon its bond angles would be 108°, but tetrahedral 109.5° bond angles are expected. However, it has an unfixed puckered shape that undulates up and down.
cyclohexane (1.3 kcal/mol), C6H12 — Although the chair conformation is able to achieve ideal angles, the unstable half-chair conformation has angle strain in the C-C-C angles which range from 109.86° to 119.07°.
Bicyclics
bicyclo[1.1.0]butane (66.3 kcal/mol),
bicyclo[1.2.0]pentane (54.7 kcal/mol),
[[bicyclo[1.3.0]hexane]] (26 kcal/mol),
norbornane (16.6 kcal/mol),
Ring strain can be considerably higher in bicyclic systems. For example, bicyclobutane, C4H6, is noted for being one of the most strained compounds that is isolatable on a large scale; its strain energy is estimated at 63.9 kcal mol−1 (267 kJ mol−1).
Cyclopropane has a lesser amount of ring strain since it has the least amount of unsaturation; as a result, increasing the amount of unsaturation leads to greater ring strain. For example, cyclopropene has a greater amount of ring strain than cyclopropane because it has more unsaturation.
Applications
The potential energy and unique bonding structure contained in the bonds of molecules with ring strain can be used to drive reactions in organic synthesis. Examples of such reactions are ring opening metathesis polymerisation, photo-induced ring opening of cyclobutenes, and nucleophilic ring-opening of epoxides and aziridines.
Increased potential energy from ring strain also can be used to increase the energy released by explosives or increase their shock sensitivity. For example, the shock sensitivity of the explosive 1,3,3-Trinitroazetidine could partially or primarily explained by its ring strain.
See also
Strain (chemistry)
Alkane stereochemistry
References
Chemical bonding
Physical organic chemistry | Ring strain | Physics,Chemistry,Materials_science | 2,222 |
831,517 | https://en.wikipedia.org/wiki/122%20%28number%29 | 122 (one hundred [and] twenty-two) is the natural number following 121 and preceding 123.
In mathematics
122 is a nontotient since there is no integer with exactly 122 coprimes below it. Nor is there an integer with exactly 122 integers with common factors below it, making 122 a noncototient.
122 is a semiprime.
φ(122) = φ(σ(122)).
References
Integers | 122 (number) | Mathematics | 91 |
59,624,291 | https://en.wikipedia.org/wiki/NGC%207199 | NGC 7199 is a barred spiral galaxy registered in the New General Catalogue. It is located in the direction of the Indus constellation. It was discovered by the English astronomer John Herschel in 1835 using a 47.5 cm (18.7 inch) reflector.
See also
List of Messier objects
References
7199
Astronomical objects discovered in 1835
Indus (constellation)
Barred spiral galaxies
Discoveries by John Herschel | NGC 7199 | Astronomy | 84 |
57,184,567 | https://en.wikipedia.org/wiki/Arlo%20Technologies | Arlo Technologies is an American company that makes wireless surveillance cameras. Prior to an initial public offering (IPO) on the New York Stock Exchange in August 2018, Arlo was a brand of such products by Netgear, which retained majority control after the IPO.
According to the company, it has shipped 21.6 million devices, has 5.82 million registered accounts, and has 877,000 paid accounts, as of January 2022.
History
On February 6, 2018, Netgear made the announcement that its board of directors had unanimously approved the separation of its Arlo business from Netgear. During the second quarter of 2018, Netgear's Arlo unit became a holding of Arlo Technologies, Inc. Netgear issued less than 20% of the Arlo common stock in the IPO, allowing it to retain majority control.
The CEO of Arlo is Matthew McRae. McRae joined Netgear in October 2017 when he was hired as senior vice president of strategy.
Products
Arlo makes products such as the Arlo Security Camera, as well as portable and baby monitoring cameras. Arlo cameras are designed to save energy by use of a low-power standby mode.
Manufacturing
Arlo manufacturing is outsourced to Foxconn and Pegatron.
References
External links
2018 initial public offerings
Companies listed on the New York Stock Exchange
Companies based in San Jose, California
American companies established in 2018
Home automation companies
Netgear
Arlo | Arlo Technologies | Technology | 301 |
16,781,491 | https://en.wikipedia.org/wiki/HD%206434%20b | HD 6434 b is an extrasolar planet orbiting the star HD 6434. It has a minimum mass about half that of Jupiter. It orbits the star very close, over 2.5 times as close as Mercury orbits the Sun. For this reason it completes one orbit in only 22 days. Unlike true "hot Jupiters" like 51 Pegasi b, HD 6434 b does not have a circular orbit, but rather an eccentric one.
The planet HD 6434 b is named Eyeke. The name was selected in the NameExoWorlds campaign by Ecuador, during the 100th anniversary of the IAU. Eyeke means near in the language spoken by the Indigenous Waorani tribes.
By studying observations taken by the Hipparcos astrometric mission, a group of scientists proposed that the planet has an inclination of 179.9° (almost exactly face-on) and a mass of 196 Jupiters. If that was the case, the planet would be a red dwarf instead. However, the data was anything but conclusive, and statistically it is extremely unlikely to lie in such a position. But because the inclination is unknown, so is the true mass of the planet. Still, it is very probable that the object is a true planet.
See also
94 Ceti b
References
External links
Exoplanets discovered in 2003
Giant planets
Phoenix (constellation)
Exoplanets detected by radial velocity
Exoplanets with proper names | HD 6434 b | Astronomy | 293 |
4,262,587 | https://en.wikipedia.org/wiki/Thermodynamic%20diagrams | Thermodynamic diagrams are diagrams used to represent the thermodynamic states of a material (typically fluid) and the consequences of manipulating this material. For instance, a temperature–entropy diagram (T–s diagram) may be used to demonstrate the behavior of a fluid as it is changed by a compressor.
Overview
Especially in meteorology they are used to analyze the actual state of the atmosphere derived from the measurements of radiosondes, usually obtained with weather balloons. In such diagrams, temperature and humidity values (represented by the dew point) are displayed with respect to pressure. Thus the diagram gives at a first glance the actual atmospheric stratification and vertical water vapor distribution. Further analysis gives the actual base and top height of convective clouds or possible instabilities in the stratification.
By assuming the energy amount due to solar radiation it is possible to predict the 2 m (6.6 ft) temperature, humidity, and wind during the day, the development of the boundary layer of the atmosphere, the occurrence and development of clouds and the conditions for soaring flight during the day.
The main feature of thermodynamic diagrams is the equivalence between the area in the diagram and energy. When air changes pressure and temperature during a process and prescribes a closed curve within the diagram the area enclosed by this curve is proportional to the energy which has been gained or released by the air.
Types of thermodynamic diagrams
General purpose diagrams include:
PV diagram
T–s diagram
h–s (Mollier) diagram
Psychrometric chart
Cooling curve
Indicator diagram
Saturation vapor curve
Thermodynamic surface
Specific to weather services, there are mainly three different types of thermodynamic diagrams used:
Skew-T log-P diagram
Tephigram
Emagram
Stüve diagram
All four diagrams are derived from the physical P–alpha diagram which combines pressure (P) and specific volume (alpha) as its basic coordinates. The P–alpha diagram shows a strong deformation of the grid for atmospheric conditions and is therefore not useful in atmospheric sciences. The three diagrams are constructed from the P–alpha diagram by using appropriate coordinate transformations.
Not a thermodynamic diagram in a strict sense, since it does not display the energy–area equivalence, is the
Stüve diagram
But due to its simpler construction it is preferred in education.
Another widely-used diagram that does not display the energy–area equivalence is the θ-z diagram (Theta-height diagram), extensively used boundary layer meteorology.
Characteristics
Thermodynamic diagrams usually show a net of five different lines:
isobars = lines of constant pressure
isotherms = lines of constant temperature
dry adiabats = lines of constant potential temperature representing the temperature of a rising parcel of dry air
saturated adiabats or pseudoadiabats = lines representing the temperature of a rising parcel saturated with water vapor
mixing ratio = lines representing the dewpoint of a rising parcel
The lapse rate, dry adiabatic lapse rate (DALR) and moist adiabatic lapse rate (MALR), are obtained. With the help of these lines, parameters such as cloud condensation level, level of free convection, onset of cloud formation. etc. can be derived from the soundings.
Example
The path or series of states through which a system passes from an initial equilibrium state to a final equilibrium state and can be viewed graphically on a pressure-volume (P-V), pressure-temperature (P-T), and temperature-entropy (T-s) diagrams.
There are an infinite number of possible paths from an initial point to an end point in a process. In many cases the path matters, however, changes in the thermodynamic properties depend only on the initial and final states and not upon the path.
Consider a gas in cylinder with a free floating piston resting on top of a volume of gas at a temperature . If the gas is heated so that the temperature of the gas goes up to while the piston is allowed to rise to as in Figure 1, then the pressure is kept the same in this process due to the free floating piston being allowed to rise making the process an isobaric process or constant pressure process. This Process Path is a straight horizontal line from state one to state two on a P-V diagram.
It is often valuable to calculate the work done in a process. The work done in a process is the area beneath the process path on a P-V diagram. Figure 2 If the process is isobaric, then the work done on the piston is easily calculated. For example, if the gas expands slowly against the piston, the work done by the gas to raise the piston is the force F times the distance d. But the force is just the pressure P of the gas times the area A of the piston, F = PA. Thus
W = Fd
W = PAd
W = P(V2 − V1)
Now let’s say that the piston was not able to move smoothly within the cylinder due to static friction with the walls of the cylinder. Assuming that the temperature was increased slowly, you would find that the process path is not straight and no longer isobaric, but would instead undergo an isometric process till the force exceeded that of the frictional force and then would undergo an isothermal process back to an equilibrium state. This process would be repeated till the end state is reached. See figure 3. The work done on the piston in this case would be different due to the additional work required for the resistance of the friction. The work done due to friction would be the difference between the work done on these two process paths.
Many engineers neglect friction at first in order to generate a simplified model. For more accurate information, the height of the highest point, or the max pressure, to surpass the static friction would be proportional to the frictional coefficient and the slope going back down to the normal pressure would be the same as an isothermal process if the temperature was increased at a slow enough rate.
Another path in this process is an isometric process. This is a process where volume is held constant which shows as a vertical line on a P-V diagram. Figure 3 Since the piston is not moving during this process, there is not any work being done.
See also
Thermodynamics
Timeline of thermodynamics
References
The Physics of Atmospheres by John Houghton, Cambridge University Press 2002. Especially chapter 3.3. deals solely with the tephigram.
German version of Handbook of meteorological soaring flight from the Organisation Scientifique et Technique Internationale du Vol à Voile (OSTIV) (chapter 2.3)
Further reading
Handbook of meteorological forecasting for soaring flight WMO Technical Note No. 158. especially chapter 2.3.
External links
www.met.tamu.edu/../aws-tr79-006.pdf A very large technical manual (164 pages) how to use the diagrams.
www.comet.ucar.edu/../sld010.htm A course on how to use diagrams at Comet, the 'Cooperative Program for Operational Meteorology, Education and Training'.
diagrams
Diagrams | Thermodynamic diagrams | Physics,Chemistry,Mathematics | 1,472 |
632,827 | https://en.wikipedia.org/wiki/Turnbuckle | A turnbuckle, stretching screw or bottlescrew is a device for adjusting the tension or length of ropes, cables, tie rods, and other tensioning systems. It normally consists of two threaded eye bolts, one screwed into each end of a small metal frame, one with a conventional right-hand thread and the other with a left-hand thread. The tension can be adjusted by rotating the frame, which causes both eye bolts to be screwed in or out simultaneously, without twisting the eye bolts or attached cables.
Uses
Turnbuckles are most commonly used in applications which require a great deal of tension; they can range in mass from about for thin cable used in a garden fence, to tonnes for structural elements in buildings and suspension bridges.
Aircraft
Turnbuckles have been used in aircraft construction, especially during the early years of aviation. Historically, biplanes might use turnbuckles to adjust the tension on structural wires bracing their wings. Turnbuckles are also widely used on flexible cables in flight control systems. In both cases they are secured with lockwire or specifically designed wire clips to prevent them from turning and losing tension due to vibration.
Shipping
Turnbuckles are used for tensioning a ship's rigging and lashings. A variant of the turnbuckle called a bottle screw features an enclosed tubular body.
Entertainment industry
Turnbuckles are used in nearly all rigging performed in the entertainment industry, including theatre, film, and live concert performances. In entertainment rigging, turnbuckles are more commonly used to make small adjustments in line lengths. This is generally to make a flown (hoisted) unit sit parallel to the stage. Another way a turnbuckle could prove helpful is with making very minor height or angle adjustments.
Pipe systems
Turnbuckles are used in piping systems as a way to provide minor adjustments for field inconsistencies. This also allows for a minimum amount of resistance when transferring the load to the support components.
Orthopaedics
A type of splint is used for upper limb to produce gradual stretching over contracted joint by its turn buckle mechanism. Used to treat stiff elbow and Volkmann Ischemic Contracture.
Gallery
See also
Buffers and chain coupler
Guy-wire
Mechanical joint
References
External links
Hardware (mechanical)
Sailing rigs and rigging
Ring (martial arts) | Turnbuckle | Physics,Technology,Engineering | 470 |
3,449,340 | https://en.wikipedia.org/wiki/Ovary%20%28botany%29 | In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule(s) and is located above or below or at the point of connection with the base of the petals and sepals. The pistil may be made up of one carpel or of several fused carpels (e.g. dicarpel or tricarpel), and therefore the ovary can contain part of one carpel or parts of several fused carpels. Above the ovary is the style and the stigma, which is where the pollen lands and germinates to grow down through the style to the ovary, and, for each individual pollen grain, to fertilize one individual ovule. Some wind pollinated flowers have much reduced and modified ovaries.
Fruits
A fruit is the mature, ripened ovary of a flower following double fertilization in an angiosperm. Because gymnosperms do not have an ovary but reproduce through fertilization of unprotected ovules, they produce naked seeds that do not have a surrounding fruit, this meaning that juniper and yew "berries" are not fruits, but modified cones. Fruits are responsible for the dispersal and protection of seeds in angiosperms and cannot be easily characterized due to the differences in defining culinary and botanical fruits.
Development
After double fertilization and ripening, the ovary becomes the fruit, the ovules inside the ovary become the seeds of that fruit, and the egg within the ovule becomes the zygote. Double fertilization of the central cell in the ovule produces the nutritious endosperm tissue that surrounds the developing zygote within the seed. Angiosperm ovaries do not always produce a fruit after the ovary has been fertilized. Problems that can arise during the developmental process of the fruit include genetic issues, harsh environmental conditions, and insufficient energy which may be caused by competition for resources between ovaries; any of these situations may prevent maturation of the ovary.
Dispersal and evolutionary significance
Fruits are important in the dispersal and protection of seeds, and variation in fruit shape or size results from an evolutionary response that aids in the dispersal of seeds in different environments. For example, the seeds of large fleshy fruits are often dispersed through endozoochory; this means that animals consume the fleshy fruit and as a result disperse its seeds with their movement. The seeds of fruits can be dispersed by endozoochory, gravity, wind, or other means.
Complications and types of fruits
There are some complications to the definition of a fruit, as not all botanical fruits can be identified as culinary fruits. A ripened ovary may be a fleshy fruit such as a grapefruit or a dry fruit such as a nut. Further complicating this, culinary nuts are not always botanical nuts; some culinary nuts such as the coconut and almond are another type of fruit called a drupe.
In this same way, not all "fruits" are true fruits. A true fruit only consists of the ripened ovary and its contents. Fruits can be separated into three major categories: simple fruits, aggregate fruits, and multiple fruits. Simple fruits like oranges are formed from a single ovary which may or may not consist of multiple parts, while aggregate and multiple fruits are formed from several ovaries together. Aggregate fruits like raspberries are the ripened ovaries of one flower that form a single fruit, and multiple fruits like pineapples are formed from the ovaries of separate flowers that are close together.
Because aggregate and multiple fruits are formed from many ripened ovaries together, they are actually infructescences or groups of fruits that are arranged together in a structure. Some fruits, like the apple, are accessory fruits which can include other parts of the flower such as the receptacle, hypanthium, perianth, or calyx in addition to the mature and ripened ovary.
Parts of the ovary
Locules are chambers within the ovary of the flower and fruits. The locules contain the ovules (seeds), and may or may not be filled with fruit flesh. Depending on the number of locules in the ovary, fruits can be classified as uni-locular (unilocular), bi-locular, tri-locular or multi-locular. Some plants have septa between the carpels; the number of locules present in a gynoecium may be equal to or less than the number of carpels, depending on whether septa are present.
The ovules are attached to parts of the interior ovary walls called the placentae. Placental areas occur in various positions, corresponding to various parts of the carpels that make up the ovary. See Ovule#Location within the plant. An obturator is present in the ovary of some plants, near the micropyle of each ovule. It is an outgrowth of the placenta, important in nourishing and guiding pollen tubes to the micropyle.
The ovary of some types of fruit is dehiscent; the ovary wall splits into sections called valves. There is no standard correspondence between the valves and the position of the septa; the valves may separate by splitting the septa (septicidal dehiscence), or by spitting between them (loculicidal dehiscence), or the ovary may open in other ways, as through pores or because a cap falls off.
Classification based on position
The terminology of the positions of ovaries is determined by the insertion point, where the other floral parts (perianth and androecium) come together and attach to the surface of the ovary. If the ovary is situated above the insertion point, it is superior; if below, inferior.
Superior ovary
A superior ovary is an ovary attached to the receptacle above the attachment of other floral parts. A superior ovary is found in types of fleshy fruits such as true berries, drupes, etc. A flower with this arrangement is described as hypogynous. Examples of this ovary type include the legumes (beans and peas and their relatives).
Half-inferior ovary
A half-inferior ovary (also known as "half-superior", "subinferior", or "partially inferior") is embedded or surrounded by the receptacle. This occurs in flowers of the family Lythraceae, which includes the crape myrtles. Such flowers are termed perigynous or half-epigynous. In some classifications, half-inferior ovaries are not recognized and are instead grouped with either the superior or inferior ovaries.
More specifically, a half-inferior ovary has nearly equal portions of ovary above and below the insertion point. Other varying degrees of inferiority can be described by other fractions. For instance, a "one-fifth inferior ovary" has approximately one fifth of its length under the insertion point. Likewise, only one quarter portion of a "three-quarters inferior ovary" is above the insertion.
Inferior ovary
An inferior ovary lies below the attachment of other floral parts. A pome is a type of fleshy fruit that is often cited as an example, but close inspection of some pomes (such as Pyracantha) will show that it is really a half-inferior ovary. Flowers with inferior ovaries are termed epigynous. Some examples of flowers with an inferior ovary are orchids (inferior capsule), Fuchsia (inferior berry), banana (inferior berry), Asteraceae (inferior achene-like fruit, called a cypsela) and the pepo of the squash, melon and gourd family, Cucurbitaceae.
See also
Fruit anatomy
References
Organs (anatomy)
Plant morphology
Plant reproductive system | Ovary (botany) | Biology | 1,681 |
32,233,628 | https://en.wikipedia.org/wiki/EGR4 | Early growth response protein 4 (EGR-4), also known as AT133, is a protein that in humans is encoded by the EGR4 gene.
EGR-4 is a member of the early growth response (EGF) family of zinc finger transcription factors.
References
Further reading
Molecular neuroscience
Transcription factors
Zinc proteins | EGR4 | Chemistry,Biology | 68 |
6,771,335 | https://en.wikipedia.org/wiki/Adastral%20Park | Adastral Park is a science campus based on part of the old Royal Air Force Station at Martlesham Heath, near Ipswich in the English county of Suffolk.
When the site opened it was known as the Post Office Research Station, but it was subsequently renamed BT Research Laboratories or BT Labs and later Adastral Park to reflect an expansion in the organisations and activities co-located with BT Labs at the campus.
History
The original laboratories (when BT was part of the Post Office) were first opened by Elizabeth II in 1975. Prior to this the Post Office Research Station was at Dollis Hill in northwest London. Martlesham Heath was chosen as the site for a research facility because the surrounding countryside was relatively flat and therefore ideal for testing the radio-based communication systems in vogue at the time.
Initially, research was carried out into postal sorting and delivery technology, and telecommunications. After the Post Office was split apart and prior to British Telecom's privatisation in the early 1980s, the research concentrated on telecommunications.
In keeping with the stellar theme of the site name, buildings on site are named after stars or constellations (an example being the Main Laboratory Block now named the Orion building). The Orion building is easily recognisable from the nearby A12 road with its radio tower, now named Pegasus tower, dominating the skyline.
The change to the current name occurred in the late 1990s with the aim of turning the site into a high-technology business park, no longer exclusively for the use of BT. The name was created by Stewart Davies, the CEO of the BT business (BT Exact Technologies) headquartered at the site at that time. It is derived from the motto of the Royal Air Force—per ardua ad astra ("through adversity to the stars"). The Royal Air Force were prior residents of the site, as RAF Martlesham Heath. Experimental aircraft test flights flew from the airfield and the name was meant to reflect this. In March 2001, University College London, Faculty of Engineering Sciences, chose Adastral Park to set up the first-ever postgraduate research and teaching centre on an industrial campus, which was housed there until 2009. During the transformation of the business park, many of the old buildings were removed and car parks were moved to the perimeter of the site, with the centre made into open parkland with a water feature to provide a 'park' feel to the complex. The site accommodates approximately 4,000 people.
Current use
Companies based at Adastral Park besides BT (BT Applied Research) include:
Openreach
F5 Networks
Juniper Networks
GENBAND
Maly IT Solutions
Cisco
Coderus.com
CommsUnite
Fujitsu
Huawei
O2 plc
Arqiva
CIP
Milner Strategic Marketing
There is also a satellite earth station operated by Arqiva; the location was chosen for the visibility of satellites on the eastern horizon. In 2018 there were 98 high-tech companies at the site.
Peregrine falcons
BT worked with the Hawk and Owl Trust to set up a nesting box for a pair of peregrine falcons. These produced two chicks in 2019, and in 2020 a YouTube channel was set up and three chicks were produced.
Adastral New Town
Over many years, BT has put forward various proposals and plans to expand activities at the business park. In June 2001, a framework for expanding the business park was created, but it was not linked to building any residential housing on the site. At the time BT forecast 3000 to 3500 additional jobs by about 2010. In 2007, BT said that they could develop the business park without the need for the income from selling land for housing.
In 2006, Suffolk Coastal District Council (SCDC) rejected a planning application for 120 log cabins on a site next to Waldringfield Road. The rejection was on the grounds that it was too near the Area of Outstanding Natural Beauty amongst other reasons, and would result in an unacceptable increase in visitor numbers to a sensitive areas. BT initially objected on the grounds that it would interfere with their radio test area, although BT subsequently withdrew their objection provided the developer created a protective earth bund, rejected by SCDC. BT subsequently lodged a planning application for 2000 houses to be built. At its closest the site comes within of an Area of Outstanding Natural Beauty, and there are several Site of Special Scientific Interest close by, such as Newbourne Springs. In April 2018, SCDC (subsequently merged with a neighbouring council to become East Suffolk District Council) gave outline permission for the development, which is now named Brightwell Lakes.
See also
BT Research
Post Office Research Station
References
External links
Adastral Park home page
Connected Earth Museum on the origin of BT Laboratories, Martlesham
Coverage from theregister.co.uk on domain grab
Further coverage on domain grab
No to Adastral New Town
Press coverage over Adastral New Town
British Telecom buildings and structures
Buildings and structures in Suffolk
Engineering research institutes
History of telecommunications in the United Kingdom
Research institutes in Suffolk
Science parks in the United Kingdom | Adastral Park | Engineering | 1,015 |
24,005,369 | https://en.wikipedia.org/wiki/C9H18O2 | {{DISPLAYTITLE:C9H18O2}}
The molecular formula C9H18O2 (molar mass: 158.24 g/mol) may refer to:
Ethyl heptanoate
Heptyl acetate
Nonanoic acid
Pentyl butyrate, or amyl butyrate
Propyl hexanoate | C9H18O2 | Chemistry | 76 |
9,311,082 | https://en.wikipedia.org/wiki/Tapesia%20acuformis | Tapesia acuformis is the causal agent for a variety of cereal and forage grass diseases. The anamorph of T. acuformis was formerly known as the R-type strain of Pseudocercosporella herpotrichoides. The W-type strain of P. herpotrichoides is now known as T. yallundae.
Management
Agropyron elongatums genetic resistance to this disease is useful to introgress into wheat.
See also
List of rye diseases
List of wheat diseases
References
Fungal plant pathogens and diseases
Rye diseases
Wheat diseases
Dermateaceae
Fungus species | Tapesia acuformis | Biology | 127 |
43,911,141 | https://en.wikipedia.org/wiki/Edward%20F.%20Seagram | Edward Frowde Seagram (September 28, 1873 – February 1, 1937) was an entrepreneur, philanthropist and politician in Ontario, Canada. He served as mayor of Waterloo from 1906 to 1907.
The son of distiller Joseph Emm Seagram and Stephanie Urbs, he was born in Waterloo and was educated at the Lakefield Preparatory school, Trinity College and McGill University. Seagram joined his father's business in 1894. Around 1910, he purchased the Globe Furniture Company, originally based in Walkerville, and moved it to Waterloo (Globe folded in 1968.). In 1920, Seagram became president of the distillery. That same year, he purchased Mueller Cooperage, renaming it Canadian Barrels and Kegs (later Canbar of Breslau).
Seagram was also interested in horse racing. He was president of the Ontario Jockey Club and of the Seagram Stables. His horses won the King's Plate in 1923, 1926, 1928 and 1933. He helped establish the Westmount Golf and Country Club and served as first president of its board of directors. He also contributed to the Waterloo Lawn Bowling Club.
His granddaughter Sandra Seagram was the last debutante presented at the Court of St James's.
References
1873 births
1937 deaths
Mayors of Waterloo, Ontario
Canadian racehorse owners and breeders
Businesspeople from Ontario
Drink distillers
Canadian philanthropists
McGill University alumni
20th-century mayors of places in Ontario | Edward F. Seagram | Chemistry | 288 |
21,851,601 | https://en.wikipedia.org/wiki/Hadwiger%20conjecture%20%28combinatorial%20geometry%29 | In combinatorial geometry, the Hadwiger conjecture states that any convex body in n-dimensional Euclidean space can be covered by 2n or fewer smaller bodies homothetic with the original body, and that furthermore, the upper bound of 2n is necessary if and only if the body is a parallelepiped. There also exists an equivalent formulation in terms of the number of floodlights needed to illuminate the body.
The Hadwiger conjecture is named after Hugo Hadwiger, who included it on a list of unsolved problems in 1957; it was, however, previously studied by and independently, . Additionally, there is a different Hadwiger conjecture concerning graph coloring—and in some sources the geometric Hadwiger conjecture is also called the Levi–Hadwiger conjecture or the Hadwiger–Levi covering problem.
The conjecture remains unsolved even in three dimensions, though the two dimensional case was resolved by .
Formal statement
Formally, the Hadwiger conjecture is: If K is any bounded convex set in the n-dimensional Euclidean space Rn, then there exists a set of 2n scalars si and a set of 2n translation vectors vi such that all si lie in the range 0 < si < 1, and
Furthermore, the upper bound is necessary if and only if K is a parallelepiped, in which case all 2n of the scalars may be chosen to be equal to 1/2.
Alternate formulation with illumination
As shown by Boltyansky, the problem is equivalent to one of illumination: how many floodlights must be placed outside of an opaque convex body in order to completely illuminate its exterior? For the purposes of this problem, a body is only considered to be illuminated if for each point of the boundary of the body, there is at least one floodlight that is separated from the body by all of the tangent planes intersecting the body on this point; thus, although the faces of a cube may be lit by only two floodlights, the planes tangent to its vertices and edges cause it to need many more lights in order for it to be fully illuminated. For any convex body, the number of floodlights needed to completely illuminate it turns out to equal the number of smaller copies of the body that are needed to cover it.
Examples
As shown in the illustration, a triangle may be covered by three smaller copies of itself, and more generally in any dimension a simplex may be covered by n + 1 copies of itself, scaled by a factor of n/(n + 1). However, covering a square by smaller squares (with parallel sides to the original) requires four smaller squares, as each one can cover only one of the larger square's four corners. In higher dimensions, covering a hypercube or more generally a parallelepiped by smaller homothetic copies of the same shape requires a separate copy for each of the vertices of the original hypercube or parallelepiped; because these shapes have 2n vertices, 2n smaller copies are necessary. This number is also sufficient: a cube or parallelepiped may be covered by 2n copies, scaled by a factor of 1/2. Hadwiger's conjecture is that parallelepipeds are the worst case for this problem, and that any other convex body may be covered by fewer than 2n smaller copies of itself.
Known results
The two-dimensional case was settled by : every two-dimensional bounded convex set may be covered with four smaller copies of itself, with the fourth copy needed only in the case of parallelograms. However, the conjecture remains open in higher dimensions except for some special cases. The best known asymptotic upper bound on the number of smaller copies needed to cover a given body is
where is a positive constant. For small the upper bound of established by is better than the asymptotic one. In three dimensions it is known that 16 copies always suffice, but this is still far from the conjectured bound of 8 copies.
The conjecture is known to hold for certain special classes of convex bodies, including, in dimension three, centrally symmetric polyhedra and bodies of constant width. The number of copies needed to cover any zonotope (other than a parallelepiped) is at most , while for bodies with a smooth surface (that is, having a single tangent plane per boundary point), at most smaller copies are needed to cover the body, as Levi already proved.
See also
Borsuk's conjecture on covering convex bodies with sets of smaller diameter
Notes
References
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Discrete geometry
Conjectures
Unsolved problems in geometry
Eponyms in geometry | Hadwiger conjecture (combinatorial geometry) | Mathematics | 954 |
24,603 | https://en.wikipedia.org/wiki/Proteasome | Proteasomes are protein complexes which degrade ubiquitin-tagged proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that help such reactions are called proteases.
Proteasomes are part of a major mechanism by which cells regulate the concentration of particular proteins and degrade misfolded proteins. Proteins are tagged for degradation with a small protein called ubiquitin. The tagging reaction is catalyzed by enzymes called ubiquitin ligases. Once a protein is tagged with a single ubiquitin molecule, this is a signal to other ligases to attach additional ubiquitin molecules. The result is a polyubiquitin chain that is bound by the proteasome, allowing it to degrade the tagged protein. The degradation process yields peptides of about seven to eight amino acids long, which can then be further degraded into shorter amino acid sequences and used in synthesizing new proteins.
Proteasomes are found inside all eukaryotes and archaea, and in some bacteria.
In eukaryotes, proteasomes are located both in the nucleus and in the cytoplasm.
In structure, the proteasome is a cylindrical complex containing a "core" of four stacked rings forming a central pore. Each ring is composed of seven individual proteins. The inner two rings are made of seven β subunits that contain three to seven protease active sites. These sites are located on the interior surface of the rings, so that the target protein must enter the central pore before it is degraded. The outer two rings each contain seven α subunits whose function is to maintain a "gate" through which proteins enter the barrel. These α subunits are controlled by binding to "cap" structures or regulatory particles that recognize polyubiquitin tags attached to protein substrates and initiate the degradation process. The overall system of ubiquitination and proteasomal degradation is known as the ubiquitin–proteasome system.
The proteasomal degradation pathway is essential for many cellular processes, including the cell cycle, the regulation of gene expression, and responses to oxidative stress. The importance of proteolytic degradation inside cells and the role of ubiquitin in proteolytic pathways was acknowledged in the award of the 2004 Nobel Prize in Chemistry to Aaron Ciechanover, Avram Hershko and Irwin Rose.
Discovery
Before the discovery of the ubiquitin–proteasome system, protein degradation in cells was thought to rely mainly on lysosomes, membrane-bound organelles with acidic and protease-filled interiors that can degrade and then recycle exogenous proteins and aged or damaged organelles. However, work by Joseph Etlinger and Alfred L. Goldberg in 1977 on ATP-dependent protein degradation in reticulocytes, which lack lysosomes, suggested the presence of a second intracellular degradation mechanism. This was shown in 1978 to be composed of several distinct protein chains, a novelty among proteases at the time. Later work on modification of histones led to the identification of an unexpected covalent modification of the histone protein by a bond between a lysine side chain of the histone and the C-terminal glycine residue of ubiquitin, a protein that had no known function. It was then discovered that a previously identified protein associated with proteolytic degradation, known as ATP-dependent proteolysis factor 1 (APF-1), was the same protein as ubiquitin. The proteolytic activities of this system were isolated as a multi-protein complex originally called the multi-catalytic proteinase complex by Sherwin Wilk and Marion Orlowski. Later, the ATP-dependent proteolytic complex that was responsible for ubiquitin-dependent protein degradation was discovered and was called the 26S proteasome.
Much of the early work leading up to the discovery of the ubiquitin proteasome system occurred in the late 1970s and early 1980s at the Technion in the laboratory of Avram Hershko, where Aaron Ciechanover worked as a graduate student. Hershko's year-long sabbatical in the laboratory of Irwin Rose at the Fox Chase Cancer Center provided key conceptual insights, though Rose later downplayed his role in the discovery. The three shared the 2004 Nobel Prize in Chemistry for their work in discovering this system.
Although electron microscopy data revealing the stacked-ring structure of the proteasome became available in the mid-1980s, the first structure of the proteasome core particle was not solved by X-ray crystallography until 1994. In 2018, the first atomic structures of the human 26S proteasome holoenzyme in complex with a polyubiquitylated protein substrate were solved by cryogenic electron microscopy, revealing mechanisms by which the substrate is recognized, deubiquitylated, unfolded and degraded by the human 26S proteasome.
Structure and organization
The proteasome subcomponents are often referred to by their Svedberg sedimentation coefficient (denoted S). The proteasome most exclusively used in mammals is the cytosolic 26S proteasome, which is about 2000 kilodaltons (kDa) in molecular mass containing one 20S protein subunit and two 19S regulatory cap subunits. The core is hollow and provides an enclosed cavity in which proteins are degraded; openings at the two ends of the core allow the target protein to enter. Each end of the core particle associates with a 19S regulatory subunit that contains multiple ATPase active sites and ubiquitin binding sites; it is this structure that recognizes polyubiquitinated proteins and transfers them to the catalytic core. An alternative form of regulatory subunit called the 11S particle can associate with the core in essentially the same manner as the 19S particle; the 11S may play a role in degradation of foreign peptides such as those produced after infection by a virus.
20S core particle
The number and diversity of subunits contained in the 20S core particle depends on the organism; the number of distinct and specialized subunits is larger in multicellular than unicellular organisms and larger in eukaryotes than in prokaryotes. All 20S particles consist of four stacked heptameric ring structures that are themselves composed of two different types of subunits; α subunits are structural in nature, whereas β subunits are predominantly catalytic. The α subunits are pseudoenzymes homologous to β subunits. They are assembled with their N-termini adjacent to that of the β subunits. The outer two rings in the stack consist of seven α subunits each, which serve as docking domains for the regulatory particles and the alpha subunits N-termini () form a gate that blocks unregulated access of substrates to the interior cavity. The inner two rings each consist of seven β subunits and in their N-termini contain the protease active sites that perform the proteolysis reactions. Three distinct catalytic activities were identified in the purified complex: chymotrypsin-like, trypsin-like and peptidylglutamyl-peptide hydrolyzing. The size of the proteasome is relatively conserved and is about 150 angstroms (Å) by 115 Å. The interior chamber is at most 53 Å wide, though the entrance can be as narrow as 13 Å, suggesting that substrate proteins must be at least partially unfolded to enter.
In archaea such as Thermoplasma acidophilum, all the α and all the β subunits are identical, whereas eukaryotic proteasomes such as those in yeast contain seven distinct types of each subunit. In mammals, the β1, β2, and β5 subunits are catalytic; although they share a common mechanism, they have three distinct substrate specificities considered chymotrypsin-like, trypsin-like, and peptidyl-glutamyl peptide-hydrolyzing (PHGH). Alternative β forms denoted β1i, β2i, and β5i can be expressed in hematopoietic cells in response to exposure to pro-inflammatory signals such as cytokines, in particular, interferon gamma. The proteasome assembled with these alternative subunits is known as the immunoproteasome, whose substrate specificity is altered relative to the normal proteasome.
Recently an alternative proteasome was identified in human cells that lack the α3 core subunit. These proteasomes (known as the α4-α4 proteasomes) instead form 20S core particles containing an additional α4 subunit in place of the missing α3 subunit. These alternative 'α4-α4' proteasomes have been known previously to exist in yeast. Although the precise function of these proteasome isoforms is still largely unknown, cells expressing these proteasomes show enhanced resistance to toxicity induced by metallic ions such as cadmium.
19S regulatory particle
The 19S particle in eukaryotes consists of 19 individual proteins and is divisible into two subassemblies, a 9-subunit base that binds directly to the α ring of the 20S core particle, and a 10-subunit lid. Six of the nine base proteins are ATPase subunits from the AAA Family, and an evolutionary homolog of these ATPases exists in archaea, called PAN (proteasome-activating nucleotidase). The association of the 19S and 20S particles requires the binding of ATP to the 19S ATPase subunits, and ATP hydrolysis is required for the assembled complex to degrade folded and ubiquitinated proteins. Note that only the step of substrate unfolding requires energy from ATP hydrolysis, while ATP-binding alone can support all the other steps required for protein degradation (e.g., complex assembly, gate opening, translocation, and proteolysis). In fact, ATP binding to the ATPases by itself supports the rapid degradation of unfolded proteins. However, while ATP hydrolysis is required for unfolding only, it is not yet clear whether this energy may be used in the coupling of some of these steps.
In 2012, two independent efforts have elucidated the molecular architecture of the 26S proteasome by single particle electron microscopy. In 2016, three independent efforts have determined the first near-atomic resolution structure of the human 26S proteasome in the absence of substrates by cryo-EM. In 2018, a major effort has elucidated the detailed mechanisms of deubiquitylation, initiation of translocation and processive unfolding of substrates by determining seven atomic structures of substrate-engaged 26S proteasome simultaneously. In the heart of the 19S, directly adjacent to the 20S, are the AAA-ATPases (AAA proteins) that assemble to a heterohexameric ring of the order Rpt1/Rpt2/Rpt6/Rpt3/Rpt4/Rpt5. This ring is a trimer of dimers: Rpt1/Rpt2, Rpt6/Rpt3, and Rpt4/Rpt5 dimerize via their N-terminal coiled-coils. These coiled-coils protrude from the hexameric ring. The largest regulatory particle non-ATPases Rpn1 and Rpn2 bind to the tips of Rpt1/2 and Rpt6/3, respectively. The ubiquitin receptor Rpn13 binds to Rpn2 and completes the base sub-complex. The lid covers one half of the AAA-ATPase hexamer (Rpt6/Rpt3/Rpt4) and, unexpectedly, directly contacts the 20S via Rpn6 and to lesser extent Rpn5. The subunits Rpn9, Rpn5, Rpn6, Rpn7, Rpn3, and Rpn12, which are structurally related among themselves and to subunits of the COP9 complex and eIF3 (hence called PCI subunits) assemble to a horseshoe-like structure enclosing the Rpn8/Rpn11 heterodimer. Rpn11, the deubiquitinating enzyme, is placed at the mouth of the AAA-ATPase hexamer, ideally positioned to remove ubiquitin moieties immediately before translocation of substrates into the 20S. The second ubiquitin receptor identified to date, Rpn10, is positioned at the periphery of the lid, near subunits Rpn8 and Rpn9.
Conformational changes of 19S
The 19S regulatory particle within the 26S proteasome holoenzyme has been observed in six strongly differing conformational states in the absence of substrates to date. A hallmark of the AAA-ATPase configuration in this predominant low-energy state is a staircase- or lockwasher-like arrangement of the AAA-domains. In the presence of ATP but absence of substrate three alternative, less abundant conformations of the 19S are adopted primarily differing in the positioning of the lid with respect to the AAA-ATPase module. In the presence of ATP-γS or a substrate, considerably more conformations have been observed displaying dramatic structural changes of the AAA-ATPase module. Some of the substrate-bound conformations bear high similarity to the substrate-free ones, but they are not entirely identical, particularly in the AAA-ATPase module. Prior to the 26S assembly, the 19S regulatory particle in a free form has also been observed in seven conformational states. Notably, all these conformers are somewhat different and present distinct features. Thus, the 19S regulatory particle can sample at least 20 conformational states under different physiological conditions.
Regulation of the 20S by the 19S
The 19S regulatory particle is responsible for stimulating the 20S to degrade proteins. A primary function of the 19S regulatory ATPases is to open the gate in the 20S that blocks the entry of substrates into the degradation chamber. The mechanism by which the proteasomal ATPase open this gate has been recently elucidated. 20S gate opening, and thus substrate degradation, requires the C-termini of the proteasomal ATPases, which contains a specific motif (i.e., HbYX motif). The ATPases C-termini bind into pockets in the top of the 20S, and tether the ATPase complex to the 20S proteolytic complex, thus joining the substrate unfolding equipment with the 20S degradation machinery. Binding of these C-termini into these 20S pockets by themselves stimulates opening of the gate in the 20S in much the same way that a "key-in-a-lock" opens a door. The precise mechanism by which this "key-in-a-lock" mechanism functions has been structurally elucidated in the context of human 26S proteasome at near-atomic resolution, suggesting that the insertion of five C-termini of ATPase subunits Rpt1/2/3/5/6 into the 20S surface pockets are required to fully open the 20S gate.
Other regulatory particles
20S proteasomes can also associate with a second type of regulatory particle, the 11S regulatory particle, a heptameric structure that does not contain any ATPases and can promote the degradation of short peptides but not of complete proteins. It is presumed that this is because the complex cannot unfold larger substrates. This structure is also known as PA28, REG, or PA26. The mechanisms by which it binds to the core particle through the C-terminal tails of its subunits and induces α-ring conformational changes to open the 20S gate suggest a similar mechanism for the 19S particle. The expression of the 11S particle is induced by interferon gamma and is responsible, in conjunction with the immunoproteasome β subunits, for the generation of peptides that bind to the major histocompatibility complex.
Yet another type of non-ATPase regulatory particle is the Blm10 (yeast) or PA200/PSME4 (human). It opens only one α subunit in the 20S gate and itself folds into a dome with a very small pore over it.
Assembly
The assembly of the proteasome is a complex process due to the number of subunits that must associate to form an active complex. The β subunits are synthesized with N-terminal "propeptides" that are post-translationally modified during the assembly of the 20S particle to expose the proteolytic active site. The 20S particle is assembled from two half-proteasomes, each of which consists of a seven-membered pro-β ring attached to a seven-membered α ring. The association of the β rings of the two half-proteasomes triggers threonine-dependent autolysis of the propeptides to expose the active site. These β interactions are mediated mainly by salt bridges and hydrophobic interactions between conserved alpha helices whose disruption by mutation damages the proteasome's ability to assemble. The assembly of the half-proteasomes, in turn, is initiated by the assembly of the α subunits into their heptameric ring, forming a template for the association of the corresponding pro-β ring. The assembly of α subunits has not been characterized.
Only recently, the assembly process of the 19S regulatory particle has been elucidated to considerable extent. The 19S regulatory particle assembles as two distinct subcomponents, the base and the lid. Assembly of the base complex is facilitated by four assembly chaperones, Hsm3/S5b, Nas2/p27, Rpn14/PAAF1, and Nas6/gankyrin (names for yeast/mammals). These assembly chaperones bind to the AAA-ATPase subunits and their main function seems to be to ensure proper assembly of the heterohexameric AAA-ATPase ring. To date it is still under debate whether the base complex assembles separately, whether the assembly is templated by the 20S core particle, or whether alternative assembly pathways exist. In addition to the four assembly chaperones, the deubiquitinating enzyme Ubp6/Usp14 also promotes base assembly, but it is not essential. The lid assembles separately in a specific order and does not require assembly chaperones.
Protein degradation process
Ubiquitination and targeting
Proteins are targeted for degradation by the proteasome with covalent modification of a lysine residue that requires the coordinated reactions of three enzymes. In the first step, a ubiquitin-activating enzyme (known as E1) hydrolyzes ATP and adenylylates a ubiquitin molecule. This is then transferred to E1's active-site cysteine residue in concert with the adenylylation of a second ubiquitin. This adenylylated ubiquitin is then transferred to a cysteine of a second enzyme, ubiquitin-conjugating enzyme (E2). In the last step, a member of a highly diverse class of enzymes known as ubiquitin ligases (E3) recognizes the specific protein to be ubiquitinated and catalyzes the transfer of ubiquitin from E2 to this target protein. A target protein must be labeled with at least four ubiquitin monomers (in the form of a polyubiquitin chain) before it is recognized by the proteasome lid. It is therefore the E3 that confers substrate specificity to this system. The number of E1, E2, and E3 proteins expressed depends on the organism and cell type, but there are many different E3 enzymes present in humans, indicating that there is a huge number of targets for the ubiquitin proteasome system.
The mechanism by which a polyubiquitinated protein is targeted to the proteasome is not fully understood. A few high-resolution snapshots of the proteasome bound to a polyubiquitinated protein suggest that ubiquitin receptors might be coordinated with deubiquitinase Rpn11 for initial substrate targeting and engagement. Ubiquitin-receptor proteins have an N-terminal ubiquitin-like (UBL) domain and one or more ubiquitin-associated (UBA) domains. The UBL domains are recognized by the 19S proteasome caps and the UBA domains bind ubiquitin via three-helix bundles. These receptor proteins may escort polyubiquitinated proteins to the proteasome, though the specifics of this interaction and its regulation are unclear.
The ubiquitin protein itself is 76 amino acids long and was named due to its ubiquitous nature, as it has a highly conserved sequence and is found in all known eukaryotic organisms. The genes encoding ubiquitin in eukaryotes are arranged in tandem repeats, possibly due to the heavy transcription demands on these genes to produce enough ubiquitin for the cell. It has been proposed that ubiquitin is the slowest-evolving protein identified to date. Ubiquitin contains seven lysine residues to which another ubiquitin can be ligated, resulting in different types of polyubiquitin chains. Chains in which each additional ubiquitin is linked to lysine 48 of the previous ubiquitin have a role in proteasome targeting, while other types of chains may be involved in other processes.
Deubiquitylation
Ubiquitin chains conjugated to a protein targeted for proteasomal degradation are normally removed by any one of the three proteasome-associated deubiquitylating enzymes (DUBs), which are Rpn11, Ubp6/USP14 and UCH37. This process recycles ubiquitin and is essential to maintain the ubiquitin reservoir in cells. Rpn11 is an intrinsic, stoichiometric subunit of the 19S regulatory particle and is essential for the function of 26S proteasome. The DUB activity of Rpn11 is enhanced in the proteasome as compared to its monomeric form. How Rpn11 removes a ubiquitin chain en bloc from a protein substrate was captured by an atomic structure of the substrate-engaged human proteasome in a conformation named EB. Interestingly, this structure also shows how the DUB activity is coupled to the substrate recognition by the proteasomal AAA-ATPase. In contrast to Rpn11, USP14 and UCH37 are the DUBs that do not always associated with the proteasome. In cells, about 10-40% of the proteasomes were found to have USP14 associated. Both Ubp6/USP14 and UCH37 are largely activated by the proteasome and exhibit a very low DUB activity alone. Once activated, USP14 was found to suppress proteasome function by its DUB activity and by inducing parallel pathways of proteasome conformational transitions, one of which turned out to directly prohibit substrate insertion into the AAA-ATPase, as intuitively observed by time-resolved cryogenic electron microscopy. It appears that USP14 regulates proteasome function at multiple checkpoints by both catalytically competing with Rpn11 and allosterically reprogramming the AAA-ATPase states, which is rather unexpected for a DUB. These observations imply that the proteasome regulation may depend on its dynamic transitions of conformational states.
Unfolding and translocation
After a protein has been ubiquitinated, it is recognized by the 19S regulatory particle in an ATP-dependent binding step. The substrate protein must then enter the interior of the 20S subunit to come in contact with the proteolytic active sites. Because the 20S particle's central channel is narrow and gated by the N-terminal tails of the α ring subunits, the substrates must be at least partially unfolded before they enter the core. The passage of the unfolded substrate into the core is called translocation and necessarily occurs after deubiquitination. However, the order in which substrates are deubiquitinated and unfolded is not yet clear. Which of these processes is the rate-limiting step in the overall proteolysis reaction depends on the specific substrate; for some proteins, the unfolding process is rate-limiting, while deubiquitination is the slowest step for other proteins. The extent to which substrates must be unfolded before translocation is suggested to be around 20 amino acid residues by the atomic structure of the substrate-engaged 26S proteasome in the deubiquitylation-compatible state, but substantial tertiary structure, and in particular nonlocal interactions such as disulfide bonds, are sufficient to inhibit degradation. The presence of intrinsically disordered protein segments of sufficient size, either at the protein terminus or internally, has also been proposed to facilitate efficient initiation of degradation.
The gate formed by the α subunits prevents peptides longer than about four residues from entering the interior of the 20S particle. The ATP molecules bound before the initial recognition step are hydrolyzed before translocation. While energy is needed for substrate unfolding, it is not required for translocation. The assembled 26S proteasome can degrade unfolded proteins in the presence of a non-hydrolyzable ATP analog, but cannot degrade folded proteins, indicating that energy from ATP hydrolysis is used for substrate unfolding. Passage of the unfolded substrate through the opened gate occurs via facilitated diffusion if the 19S cap is in the ATP-bound state.
The mechanism for unfolding of globular proteins is necessarily general, but somewhat dependent on the amino acid sequence. Long sequences of alternating glycine and alanine have been shown to inhibit substrate unfolding, decreasing the efficiency of proteasomal degradation; this results in the release of partially degraded byproducts, possibly due to the decoupling of the ATP hydrolysis and unfolding steps. Such glycine-alanine repeats are also found in nature, for example in silk fibroin; in particular, certain Epstein–Barr virus gene products bearing this sequence can stall the proteasome, helping the virus propagate by preventing antigen presentation on the major histocompatibility complex.
Proteolysis
The proteasome functions as an endoprotease. The mechanism of proteolysis by the β subunits of the 20S core particle is through a threonine-dependent nucleophilic attack. This mechanism may depend on an associated water molecule for deprotonation of the reactive threonine hydroxyl. Degradation occurs within the central chamber formed by the association of the two β rings and normally does not release partially degraded products, instead reducing the substrate to short polypeptides typically 7–9 residues long, though they can range from 4 to 25 residues, depending on the organism and substrate. The biochemical mechanism that determines product length is not fully characterized. Although the three catalytic β subunits have a common mechanism, they have slightly different substrate specificities, which are considered chymotrypsin-like, trypsin-like, and peptidyl-glutamyl peptide-hydrolyzing (PHGH)-like. These variations in specificity are the result of interatomic contacts with local residues near the active sites of each subunit. Each catalytic β subunit also possesses a conserved lysine residue required for proteolysis.
Although the proteasome normally produces very short peptide fragments, in some cases these products are themselves biologically active and functional molecules. Certain transcription factors regulating the expression of specific genes, including one component of the mammalian complex NF-κB, are synthesized as inactive precursors whose ubiquitination and subsequent proteasomal degradation converts them to an active form. Such activity requires the proteasome to cleave the substrate protein internally, rather than processively degrading it from one terminus. It has been suggested that long loops on these proteins' surfaces serve as the proteasomal substrates and enter the central cavity, while the majority of the protein remains outside. Similar effects have been observed in yeast proteins; this mechanism of selective degradation is known as regulated ubiquitin/proteasome dependent processing (RUP).
Ubiquitin-independent degradation
Although most proteasomal substrates must be ubiquitinated before being degraded, there are some exceptions to this general rule, especially when the proteasome plays a normal role in the post-translational processing of the protein. The proteasomal activation of NF-κB by processing p105 into p50 via internal proteolysis is one major example. Some proteins that are hypothesized to be unstable due to intrinsically unstructured regions, are degraded in a ubiquitin-independent manner. The most well-known example of a ubiquitin-independent proteasome substrate is the enzyme ornithine decarboxylase. Ubiquitin-independent mechanisms targeting key cell cycle regulators such as p53 have also been reported, although p53 is also subject to ubiquitin-dependent degradation. Finally, structurally abnormal, misfolded, or highly oxidized proteins are also subject to ubiquitin-independent and 19S-independent degradation under conditions of cellular stress.
Evolution
The 20S proteasome is both ubiquitous and essential in eukaryotes and archaea. The bacterial order Actinomycetales, also share homologs of the 20S proteasome, whereas most bacteria possess heat shock genes hslV and hslU, whose gene products are a multimeric protease arranged in a two-layered ring and an ATPase. The hslV protein has been hypothesized to resemble the likely ancestor of the 20S proteasome. In general, HslV is not essential in bacteria, and not all bacteria possess it, whereas some protists possess both the 20S and the hslV systems. Many bacteria also possess other homologs of the proteasome and an associated ATPase, most notably ClpP and ClpX. This redundancy explains why the HslUV system is not essential.
Sequence analysis suggests that the catalytic β subunits diverged earlier in evolution than the predominantly structural α subunits. In bacteria that express a 20S proteasome, the β subunits have high sequence identity to archaeal and eukaryotic β subunits, whereas the α sequence identity is much lower. The presence of 20S proteasomes in bacteria may result from lateral gene transfer, while the diversification of subunits among eukaryotes is ascribed to multiple gene duplication events.
Cell cycle control
Cell cycle progression is controlled by ordered action of cyclin-dependent kinases (CDKs), activated by specific cyclins that demarcate phases of the cell cycle. Mitotic cyclins, which persist in the cell for only a few minutes, have one of the shortest life spans of all intracellular proteins. After a CDK-cyclin complex has performed its function, the associated cyclin is polyubiquitinated and destroyed by the proteasome, which provides directionality for the cell cycle. In particular, exit from mitosis requires the proteasome-dependent dissociation of the regulatory component cyclin B from the mitosis promoting factor complex. In vertebrate cells, "slippage" through the mitotic checkpoint leading to premature M phase exit can occur despite the delay of this exit by the spindle checkpoint.
Earlier cell cycle checkpoints such as post-restriction point check between G1 phase and S phase similarly involve proteasomal degradation of cyclin A, whose ubiquitination is promoted by the anaphase promoting complex (APC), an E3 ubiquitin ligase. The APC and the Skp1/Cul1/F-box protein complex (SCF complex) are the two key regulators of cyclin degradation and checkpoint control; the SCF itself is regulated by the APC via ubiquitination of the adaptor protein, Skp2, which prevents SCF activity before the G1-S transition.
Individual components of the 19S particle have their own regulatory roles. Gankyrin, a recently identified oncoprotein, is one of the 19S subcomponents that also tightly binds the cyclin-dependent kinase CDK4 and plays a key role in recognizing ubiquitinated p53, via its affinity for the ubiquitin ligase MDM2. Gankyrin is anti-apoptotic and has been shown to be overexpressed in some tumor cell types such as hepatocellular carcinoma.
Like eukaryotes, some archaea also use the proteasome to control cell cycle, specifically by controlling ESCRT-III-mediated cell division.
Regulation of plant growth
In plants, signaling by auxins, or phytohormones that order the direction and tropism of plant growth, induces the targeting of a class of transcription factor repressors known as Aux/IAA proteins for proteasomal degradation. These proteins are ubiquitinated by SCFTIR1, or SCF in complex with the auxin receptor TIR1. Degradation of Aux/IAA proteins derepresses transcription factors in the auxin-response factor (ARF) family and induces ARF-directed gene expression. The cellular consequences of ARF activation depend on the plant type and developmental stage, but are involved in directing growth in roots and leaf veins. The specific response to ARF derepression is thought to be mediated by specificity in the pairing of individual ARF and Aux/IAA proteins.
Apoptosis
Both internal and external signals can lead to the induction of apoptosis, or programmed cell death. The resulting deconstruction of cellular components is primarily carried out by specialized proteases known as caspases, but the proteasome also plays important and diverse roles in the apoptotic process. The involvement of the proteasome in this process is indicated by both the increase in protein ubiquitination, and of E1, E2, and E3 enzymes that is observed well in advance of apoptosis. During apoptosis, proteasomes localized to the nucleus have also been observed to translocate to outer membrane blebs characteristic of apoptosis.
Proteasome inhibition has different effects on apoptosis induction in different cell types. In general, the proteasome is not required for apoptosis, although inhibiting it is pro-apoptotic in most cell types that have been studied. Apoptosis is mediated through disrupting the regulated degradation of pro-growth cell cycle proteins. However, some cell lines — in particular, primary cultures of quiescent and differentiated cells such as thymocytes and neurons — are prevented from undergoing apoptosis on exposure to proteasome inhibitors. The mechanism for this effect is not clear, but is hypothesized to be specific to cells in quiescent states, or to result from the differential activity of the pro-apoptotic kinase JNK. The ability of proteasome inhibitors to induce apoptosis in rapidly dividing cells has been exploited in several recently developed chemotherapy agents such as bortezomib and .
Response to cellular stress
In response to cellular stresses – such as infection, heat shock, or oxidative damage – heat shock proteins that identify misfolded or unfolded proteins and target them for proteasomal degradation are expressed. Both Hsp27 and Hsp90—chaperone proteins have been implicated in increasing the activity of the ubiquitin-proteasome system, though they are not direct participants in the process. Hsp70, on the other hand, binds exposed hydrophobic patches on the surface of misfolded proteins and recruits E3 ubiquitin ligases such as CHIP to tag the proteins for proteasomal degradation. The CHIP protein (carboxyl terminus of Hsp70-interacting protein) is itself regulated via inhibition of interactions between the E3 enzyme CHIP and its E2 binding partner.
Similar mechanisms exist to promote the degradation of oxidatively damaged proteins via the proteasome system. In particular, proteasomes localized to the nucleus are regulated by PARP and actively degrade inappropriately oxidized histones. Oxidized proteins, which often form large amorphous aggregates in the cell, can be degraded directly by the 20S core particle without the 19S regulatory cap and do not require ATP hydrolysis or tagging with ubiquitin. However, high levels of oxidative damage increases the degree of cross-linking between protein fragments, rendering the aggregates resistant to proteolysis. Larger numbers and sizes of such highly oxidized aggregates are associated with aging.
Dysregulation of the ubiquitin proteasome system may contribute to several neural diseases. It may lead to brain tumors such as astrocytomas. In some of the late-onset neurodegenerative diseases that share aggregation of misfolded proteins as a common feature, such as Parkinson's disease and Alzheimer's disease, large insoluble aggregates of misfolded proteins can form and then result in neurotoxicity, through mechanisms that are not yet well understood. Decreased proteasome activity has been suggested as a cause of aggregation and Lewy body formation in Parkinson's. This hypothesis is supported by the observation that yeast models of Parkinson's are more susceptible to toxicity from α-synuclein, the major protein component of Lewy bodies, under conditions of low proteasome activity. Impaired proteasomal activity may underlie cognitive disorders such as the autism spectrum disorders, and muscle and nerve diseases such as inclusion body myopathy.
Role in the immune system
The proteasome plays a straightforward but critical role in the function of the adaptive immune system. Peptide antigens are displayed by the major histocompatibility complex class I (MHC) proteins on the surface of antigen-presenting cells. These peptides are products of proteasomal degradation of proteins originated by the invading pathogen. Although constitutively expressed proteasomes can participate in this process, a specialized complex composed of proteins, whose expression is induced by interferon gamma, are the primary producers of peptides which are optimal in size and composition for MHC binding. These proteins whose expression increases during the immune response include the 11S regulatory particle, whose main known biological role is regulating the production of MHC ligands, and specialized β subunits called β1i, β2i, and β5i with altered substrate specificity. The complex formed with the specialized β subunits is known as the immunoproteasome. Another β5i variant subunit, β5t, is expressed in the thymus, leading to a thymus-specific "thymoproteasome" whose function is as yet unclear.
The strength of MHC class I ligand binding is dependent on the composition of the ligand C-terminus, as peptides bind by hydrogen bonding and by close contacts with a region called the "B pocket" on the MHC surface. Many MHC class I alleles prefer hydrophobic C-terminal residues, and the immunoproteasome complex is more likely to generate hydrophobic C-termini.
Due to its role in generating the activated form of NF-κB, an anti-apoptotic and pro-inflammatory regulator of cytokine expression, proteasomal activity has been linked to inflammatory and autoimmune diseases. Increased levels of proteasome activity correlate with disease activity and have been implicated in autoimmune diseases including systemic lupus erythematosus and rheumatoid arthritis.
The proteasome is also involved in Intracellular antibody-mediated proteolysis of antibody-bound virions. In this neutralisation pathway, TRIM21 (a protein of the tripartite motif family) binds with immunoglobulin G to direct the virion to the proteasome where it is degraded.
Proteasome inhibitors
Proteasome inhibitors have effective anti-tumor activity in cell culture, inducing apoptosis by disrupting the regulated degradation of pro-growth cell cycle proteins. This approach of selectively inducing apoptosis in tumor cells has proven effective in animal models and human trials.
Lactacystin, a natural product synthesized by Streptomyces bacteria, was the first non-peptidic proteasome inhibitor discovered and is widely used as a research tool in biochemistry and cell biology. Lactacystin was licensed to Myogenics/Proscript, which was acquired by Millennium Pharmaceuticals, now part of Takeda Pharmaceuticals. Lactacystin covalently modifies the amino-terminal threonine of catalytic β subunits of the proteasome, particularly the β5 subunit responsible for the proteasome's chymotrypsin-like activity. This discovery helped to establish the proteasome as a mechanistically novel class of protease: an amino-terminal threonine protease.
Bortezomib (Boronated MG132), a molecule developed by Millennium Pharmaceuticals and marketed as Velcade, is the first proteasome inhibitor to reach clinical use as a chemotherapy agent. Bortezomib is used in the treatment of multiple myeloma. Notably, multiple myeloma has been observed to result in increased proteasome-derived peptide levels in blood serum that decrease to normal levels in response to successful chemotherapy. Studies in animals have indicated that bortezomib may also have clinically significant effects in pancreatic cancer. Preclinical and early clinical studies have been started to examine bortezomib's effectiveness in treating other B-cell-related cancers, particularly some types of non-Hodgkin's lymphoma. Clinical results also seem to justify use of proteasome inhibitor combined with chemotherapy, for B-cell acute lymphoblastic leukemia Proteasome inhibitors can kill some types of cultured leukemia cells that are resistant to glucocorticoids.
The molecule ritonavir, marketed as Norvir, was developed as a protease inhibitor and used to target HIV infection. However, it has been shown to inhibit proteasomes as well as free proteases; to be specific, the chymotrypsin-like activity of the proteasome is inhibited by ritonavir, while the trypsin-like activity is somewhat enhanced. Studies in animal models suggest that ritonavir may have inhibitory effects on the growth of glioma cells.
Proteasome inhibitors have also shown promise in treating autoimmune diseases in animal models. For example, studies in mice bearing human skin grafts found a reduction in the size of lesions from psoriasis after treatment with a proteasome inhibitor. Inhibitors also show positive effects in rodent models of asthma.
Labeling and inhibition of the proteasome is also of interest in laboratory settings for both in vitro and in vivo study of proteasomal activity in cells. The most commonly used laboratory inhibitors are lactacystin and the peptide aldehyde MG132 initially developed by Goldberg lab. Fluorescent inhibitors have also been developed to specifically label the active sites of the assembled proteasome.
Clinical significance
The proteasome and its subunits are of clinical significance for at least two reasons: (1) a compromised complex assembly or a dysfunctional proteasome can be associated with the underlying pathophysiology of specific diseases, and (2) they can be exploited as drug targets for therapeutic interventions. More recently, more effort has been made to consider the proteasome for the development of novel diagnostic markers and strategies. An improved and comprehensive understanding of the pathophysiology of the proteasome should lead to clinical applications in the future.
The proteasomes form a pivotal component for the ubiquitin–proteasome system (UPS) and corresponding cellular Protein Quality Control (PQC). Protein ubiquitination and subsequent proteolysis and degradation by the proteasome are important mechanisms in the regulation of the cell cycle, cell growth and differentiation, gene transcription, signal transduction and apoptosis. Proteasome defects lead to reduced proteolytic activity and the accumulation of damaged or misfolded proteins, which may contribute to neurodegenerative disease, cardiovascular diseases, inflammatory responses and autoimmune diseases, and systemic DNA damage responses leading to malignancies.
Research has implicated UPS defects in the pathogenesis of neurodegenerative and myodegenerative disorders, including Alzheimer's disease, Parkinson's disease and Pick's disease, amyotrophic lateral sclerosis (ALS), Huntington's disease, Creutzfeldt–Jakob disease, and motor neuron diseases, polyglutamine (PolyQ) diseases, muscular dystrophies and several rare forms of neurodegenerative diseases associated with dementia. As part of the ubiquitin–proteasome system (UPS), the proteasome maintains cardiac protein homeostasis and thus plays a significant role in cardiac ischemic injury, ventricular hypertrophy and heart failure. Additionally, evidence is accumulating that the UPS plays an essential role in malignant transformation. UPS proteolysis plays a major role in responses of cancer cells to stimulatory signals that are critical for the development of cancer. Accordingly, gene expression by degradation of transcription factors, such as p53, c-jun, c-Fos, NF-κB, c-Myc, HIF-1α, MATα2, STAT3, sterol-regulated element-binding proteins and androgen receptors are all controlled by the UPS and thus involved in the development of various malignancies. Moreover, the UPS regulates the degradation of tumor suppressor gene products such as adenomatous polyposis coli (APC) in colorectal cancer, retinoblastoma (Rb). and von Hippel–Lindau tumor suppressor (VHL), as well as a number of proto-oncogenes (Raf, Myc, Myb, Rel, Src, Mos, ABL). The UPS is also involved in the regulation of inflammatory responses. This activity is usually attributed to the role of proteasomes in the activation of NF-κB which further regulates the expression of pro inflammatory cytokines such as TNF-α, IL-β, IL-8, adhesion molecules (ICAM-1, VCAM-1, P-selectin) and prostaglandins and nitric oxide (NO). Additionally, the UPS also plays a role in inflammatory responses as regulators of leukocyte proliferation, mainly through proteolysis of cyclines and the degradation of CDK inhibitors. Lastly, autoimmune disease patients with SLE, Sjögren syndrome and rheumatoid arthritis (RA) predominantly exhibit circulating proteasomes which can be applied as clinical biomarkers.
See also
The Proteolysis Map
DSS1/SEM1 protein family
Exosome complex
Endoplasmic-reticulum-associated protein degradation
JUNQ and IPOD
References
Further reading
The Yeast 26S Proteasome with list of subunits and pictures
External links
Proteasome subunit nomenclature guide
3D proteasome structures in the EM Data Bank(EMDB)
Key points of proteasome function
Proteins
Protein complexes
Organelles
Apoptosis | Proteasome | Chemistry | 9,993 |
76,467,091 | https://en.wikipedia.org/wiki/Fracture%20critical%20bridge | A fracture critical bridge is a bridge or similar span that is vulnerable to collapse of one or more spans as a result of the failure in tension of a single element. While a fracture critical design is not considered unsafe, it is subject to special inspection requirements that focus on the tension elements of its structure.
Definition
For a bridge to be defined as fracture critical:
It must possess structural members that are subject to tensile stresses from bending or axial forces.
The members must be non-redundant, lacking alternate load paths or means of safely redistributing forces in the event of a tensile failure.
While members subject to compressive stress may also fail catastrophically, they typically do not fail from crack initiation.
Examples of bridge designs that would typically be considered fracture critical are:
Most truss bridges with two main load-bearing assemblies
Two-beam girder bridges (three-beam bridges in California)
Two-cell steel box girder bridges (three-beam bridges in California)
Main suspension cables and hanger cables of suspension bridges
Cable-stayed bridges
Steel ties in tied-arch or tied-truss bridges
Pin-and-hanger assemblies in two-beam bridges
Steel floor beams and cross girders
Steel bent assemblies under tensile stress
Movable and pontoon bridges
History
The designation and inspection protocols for fracture critical bridges were developed following the failure of an eyebar at the Silver Bridge at Point Pleasant, West Virginia, which precipitated the bridge's collapse into the Ohio River in 1967, resulting in 46 deaths. The disaster resulted in the establishment of the National Bridge Inventory, using the National Bridge Inspection Standards (NBIS) (CFR Title 23, Part 650).
In May 2022 new NBIS guidance established additional terminology to describe new forms of redundancy. These are:
System redundancy, in which the fracture of a primary member will not result in collapse
Internal redundancy, in which a fracture will not propagate through a member that is not system redundant, the member being itself redundant
Load path redundancy, where three or more primary load-carrying elements are present
See also
Fracture mechanics
Single point of failure
Jesus nut
References
Bridge design | Fracture critical bridge | Engineering | 438 |
78,142,608 | https://en.wikipedia.org/wiki/Trecadrine | Trecadrine () is a drug that was originally developed as an anti-ulcer agent but was found to act as a β3-adrenergic receptor agonist with potential anti-obesity and anti-diabetic properties. It is selective for the β3-adrenergic receptor, lacking activity at the β1- and β2-adrenergic receptors. The drug is orally active. Structurally, trecadrine is a substituted β-hydroxyamphetamine and derivative of β-hydroxy-N-methylamphetamine (ephedrine, pseudoephedrine) with a tricyclic moiety attached at the amine.
References
Abandoned drugs
Anti-diabetic drugs
Anti-obesity drugs
Beta3-adrenergic agonists
Drugs for acid-related disorders
Methamphetamines
Sympathomimetics
Tricyclic compounds
Phenethylamines
Ethanolamines
Dibenzocycloheptenes | Trecadrine | Chemistry | 206 |
70,317,714 | https://en.wikipedia.org/wiki/Honorary%20Diploma%20of%20the%20Cabinet%20of%20Ministers%20of%20Ukraine | The Honorary Diploma of the Cabinet of Ministers of Ukraine is a government award for many years of hard work, exemplary performance of official duties, personal contribution to economic, scientific, technical, socio-cultural, military, public and other spheres of activity, service to the Ukrainian people in promoting the rule of law and implementation of measures to ensure the protection of the rights and freedoms of citizens, the development of democracy, and the effective operation of executive bodies and local governments.
Recipients
See also
Honorary Diploma of the Verkhovna Rada of Ukraine
Diploma of the Verkhovna Rada of Ukraine
Awards of Ukraine
Orders, decorations, and medals of Ukraine
References
Ukrainian awards
Badges
Recipients of the Honorary Diploma of the Cabinet of Ministers of Ukraine | Honorary Diploma of the Cabinet of Ministers of Ukraine | Mathematics | 147 |
43,198,485 | https://en.wikipedia.org/wiki/List%20of%20VLF-transmitters | A list of VLF-transmitters and LF-transmitters, which work or worked on frequencies below 100 kHz.
List of VLF transmissions
Demolished
References
Time signal radio stations
Radio navigation
Submarines
Military radio systems
Radio spectrum | List of VLF-transmitters | Physics | 44 |
10,400,397 | https://en.wikipedia.org/wiki/Mixed%20dark%20matter | Mixed dark matter (MDM) is a dark matter (DM) model proposed during the late 1990s.
Mixed dark matter is also called hot + cold dark matter. The most abundant form of dark matter is cold dark matter, almost one fourth of the energy contents of the Universe. Neutrinos are the only known particles whose Big-Bang thermal relic should compose at least a fraction of Hot dark matter (HDM), albeit other candidates are speculated to exist. In the early 1990s, the power spectrum of fluctuations in the galaxy clustering did not agree entirely with the predictions for a standard cosmology built around pure cold DM. Mixed dark matter with a composition of about 80% cold and 20% hot (neutrinos) was investigated and found to agree better with observations. This large amount of HDM was made obsolete by the discovery in 1998 of the acceleration of universal expansion, which eventually led to the dark energy + dark matter paradigm of this decade.
The cosmological effects of cold DM are almost opposite to the hot DM effects. Given that cold DM promotes the growth of large scale structures, it is often believed to be composed of Weakly interacting massive particles (WIMPs). Conversely hot DM suffers of free-streaming for most of the history of the Universe, washing-out the formation of small scales. In other words, the mass of hot DM particles is too small to produce the observed gravitationally bounded objects in the Universe. For that reason, the hot DM abundance is constrained by Cosmology to less than one percent of the Universe contents.
The Mixed Dark Matter scenario recovered relevance when DM was proposed to be a thermal relic of a Bose–Einstein condensate made of very light bosonic particles, as light as neutrinos or even lighter like the Axion. This cosmological model predicts that cold DM is made of many condensed particles, while a small fraction of these particles resides in excited energetic states contributing to hot DM.
References
Dark matter | Mixed dark matter | Physics,Astronomy | 413 |
48,323,964 | https://en.wikipedia.org/wiki/HTC%20One%20M9%2B | The HTC One M9+ is an Android smartphone manufactured and marketed by HTC which was announced on April 8, 2015. Initially on launch, the device was only sold in China. In July 2015, the device was released in Europe excluding the United Kingdom.
The device is an upscaled version of the One M9 where it comes with a larger screen and fingerprint sensor.
On September 29, 2015, HTC relaunched the One M9+ as the HTC One M9+ Supreme Camera Edition which features an upgraded camera module and it was released in Taiwan on October 6, 2015.
Specifications
Hardware
The unibody design of the device is similar to the One M9. the device features a multi directional fingerprint sensor which is embedded along with the home button located on the bottom of the front side of the phone. The device weighs with the dimensions of height, width and depth. The display of the device is WQHD with a resolution of 1440 x 2562 pixels and pixel density of 565 ppi.
The device features an octa-core MediaTek HelioX10 MT6795 system on chip with the speed of 2.2 GHz instead of the Qualcomm Snapdragon 810. The internal storage of the device is 32 GB with expandable storage via microSD card up to 2 TB. The memory of the device is 3 GB LPDDR4 RAM.
The HTC One M9+ is equipped with a 20 megapixel BSI rear-facing camera with Toshiba T4AKP7 CMOS image sensor dual-LED dual tone flash, f/2.2 aperture, 27.8 mm lens covered with sapphire. Similarly found in the One M8, The main camera is accompanied by a second, 2-megapixel depth of field sensor (OmniVision OV2722) located directly above the main camera as a part of the device's "Duo Camera" system. The camera is also capable of recording videos in 4K (2160p) resolution. Similar to the One M9, the front facing camera is UltraPixel image sensor (which has larger pixels in its sensor, but sacrificed megapixel size for enhanced low-light capabilities) with ƒ/2.0 aperture and 26.8 mm lens which is also capable of recording videos at 1080p.
Supreme Camera Edition
In Taiwan, HTC released an upgraded version of the M9+, called the One M9+ Supreme Camera Edition (known as "HTC M9+ with laser autofocus and optical stabilizer" or "HTC M9+ Aurora edition" in Taiwan) featuring an improved Sony IMX230 camera module. Unlike the One M9+, the device's rear camera is equipped with a 21 megapixel along with optical image stabilization, 0.1 second phase detection autofocus and infrared laser auto focus.
References
External links
Android (operating system) devices
One (2015)
Mobile phones introduced in 2015
Discontinued flagship smartphones
Mobile phones with multiple rear cameras
Mobile phones with infrared transmitter | HTC One M9+ | Technology | 634 |
65,415,238 | https://en.wikipedia.org/wiki/Rule%2063 | Rule 63, commonly referred to as genderbend, is an Internet meme that states that, as a rule, "for every character there is a gender swapped version of that character". It is one of the "Rules of the Internet" that began in 2006 as a Netiquette guide on 4chan and were eventually expanded upon by including deliberately mocking rules, of which Rule 63 is an example. It began to see general use in fandom communities as a term to refer to both fan-made and official gender flips of existing fictional characters.
Origin
Prior to the creation of Rule 63, gender flipping was popularized in video games in the 1990s by the finishing move of Darkstalkers character Demitri Maximoff, a vampire. Called the "Midnight Bliss", it involved tossing a rose at a character to transform them into a helpless maiden and completely drain them of life energy. This meant that female versions of all the game's male characters had to be created, as well as those of Street Fighter and SNK characters when SNK vs. Capcom included Maximoff. These female interpretations became popular and resulted in large amounts of fan art, as well as prompting art of gender-swaps of other male and female characters.
Rule 63 was created in mid-2007 as an addition to the humorous "Rules of the Internet", originally created around the end of 2006 on 4chan. It lists two statements:
"for every given male character, there is a female version of that character", and
"for every given female character, there is a male version of that character".
The trope, originally seen primarily unofficially, later became more widely disseminated in popular culture, with critics stating that it had been "recognized by Hollywood".
Usage
Rule 63 is commonly used as a term to refer to gender-swapped interpretations of existing characters in fanworks, such as fan art, fan fiction and cosplay, and it is particularly pervasive in the anime and manga community, where communities sprang up built around romantic gender-swap relationships. It also often overlaps with the creation of moe anthropomorphic female versions of non-human, male characters. A well-known example of this is Bowsette, a female version of the Mario antagonist Bowser that became one of the most popular Internet memes of 2018. However, it has also been used by critics to refer to official characters who are gender-swapped versions of older characters or fictional beings, such as Number Six from Battlestar Galactica being a "sexy female" version of a Cylon Centurion, and the female main cast of the 2016 reboot of Ghostbusters.
The creation of Rule 63 cosplays such as gender-swapped superheroes has been cited as popular among female cosplayers as giving them the ability to portray roles beyond socially approved gendered scripts. It is seen as empowering, allowing cosplayers to wear clothing and weapons usually not afforded to female characters. However, certain characters with inherent gender fluidity are said to work better than others. Such gender-bending cosplay, which allows the cosplayer to choose what behavior enhances the performance, can be contrasted with crossplay, which completely immerses the cosplayer in the codes of another gender.
Notable examples
In film and television
Adventure Time received a spin-off series entitled Fionna and Cake, based on the eponymous episode of the original show, which features Fionna and Cake, gender-swapped versions of Finn and Jake as main characters, as well as genderbent versions of other characters that feature in later episodes.
The 2016 Ghostbusters reboot featured a cast of female leads that was called "proof of Rule 63", with similarities noted between each team member and one of the original male team members. It was called an official acknowledgement of what was formerly an unofficial, fan-driven phenomenon.
In an episode of The Loud House titled One of the Boys, Lincoln has a dream of traveling to an alternate dimension where all his sisters are male. Near the end of the episode, he travels to another dimension where he is female. A picture of him and a female version of Clyde, his best friend, can be seen in "her" room.
In an episode of Malcolm in the Middle, season 4, episode 10, titled "If Boys Were Girls", Lois pictures Reese, Malcolm, and Dewey as girls, named Renee, Mallory, and Daisy, respectively. Francis is also a girl named Frances, with Christopher Kennedy Masterson in drag.
In video games
In the Mario series, the fan-made Bowsette is a female version of the male antagonist Bowser, created through the use of the Super Crown, a power-up that imparts the appearance and abilities of Princess Peach on its user. Nintendo's official clarification is that the item is only usable by Toadette, and the creation of Bowsette is "technically impossible".
In Shovel Knight, a "Body Swap Mode" (originally called "Gender Swap") was added after it was funded as a Kickstarter goal, allowing the player to change the secondary sex characteristics of every major character in the game (and, independently, their pronouns) via the settings menu. The developers endeavored to maintain parity with the original character designs by only making their swapped version as gendered as the original, as well as matching their existing personality and gameplay.
In the Zelda series, the character Linkle was created by Nintendo as an alternate-universe gender-swap of the typical main character, Link. However, she does not possess his powers, and is instead a normal girl who dual-wields a pair of crossbows. Made playable in Hyrule Warriors Legends, she was also modded into The Legend of Zelda: Breath of the Wild by a fan to replace Link. The character Sheik, who Princess Zelda has the ability to transform into in The Legend of Zelda: Ocarina of Time, has been called the most iconic example of female-to-male gender-swapping in gaming, although Sheik has both male and female characteristics.
See also
Rule 34 – another Internet rule.
References
External links
Internet terminology
Internet memes introduced in 2007
Gender and entertainment
Gender fluidity
63
4chan phenomena | Rule 63 | Technology | 1,280 |
2,368,803 | https://en.wikipedia.org/wiki/Magnetic%20flow%20meter | A magnetic flow meter (mag meter, electromagnetic flow meter) is a transducer that measures fluid flow by the voltage induced across the liquid by its flow through a magnetic field. A magnetic field is applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The physical principle at work is electromagnetic induction. The magnetic flow meter requires a conducting fluid, for example, water that contains ions, and an electrical insulating pipe surface, for example, a rubber-lined steel tube.
If the magnetic field direction were constant, electrochemical and other effects at the electrodes would make the potential difference
difficult to distinguish from the fluid flow induced potential difference. To show this in modern magnetic flowmeters, the magnetic field is constantly reversed, cancelling out the electrochemical potential difference, which does not change direction with the magnetic field. This however prevents the use of permanent magnets for magnetic flowmeters.
See also
Electromagnetic pump
Flow measurement
Magnetohydrodynamics
Water metering
External links
3D animation of the Electromagnetic Flow Measuring Principle
eFunda: Introduction to Magnetic Flowmeters
Principles of Electromagnetic Flow Measurement
eLearning course on electromagnetic flow meters
Flow meters
Electromagnetic components | Magnetic flow meter | Chemistry,Technology,Engineering | 246 |
16,085,364 | https://en.wikipedia.org/wiki/Organisms%20involved%20in%20water%20purification | Most organisms involved in water purification originate from the waste, wastewater or water stream itself or arrive as resting spore of some form from the atmosphere. In a very few cases, mostly associated with constructed wetlands, specific organisms are planted to maximise the efficiency of the process.
Role of biota
Biota are an essential component of most sewage treatment processes and many water purification systems. Most of the organisms involved are derived from the waste, wastewater or water stream itself or from the atmosphere or soil water. However some processes, especially those involved in removing very low concentrations of contaminants, may use engineered eco-systems created by the introduction of specific plants and sometimes animals. Some full scale sewage treatment plants also use constructed wetlands to provide treatment.
Pollutants in wastewater
Pathogens
Parasites, bacteria and viruses may be injurious to the health of people or livestock ingesting the polluted water. These pathogens may have originated from sewage or from domestic or wild bird or mammal feces. Pathogens may be killed by ingestion by larger organisms, oxidation, infection by phages or irradiation by ultraviolet sunlight unless that sunlight is blocked by plants or suspended solids.
Suspended solids
Particles of soil or organic matter may be suspended in the water. Such materials may give the water a cloudy or turbid appearance. The anoxic decomposition of some organic materials may give rise to obnoxious or unpleasant smells as sulphur containing compounds are released.
Nutrients
Compounds containing nitrogen, potassium or phosphorus may encourage growth of aquatic plants and thus increase the available energy in the local food-web. this can lead to increased concentrations of suspended organic material. In some cases specific micro-nutrients may be required to allow the available nutrients to be fully utilised by living organisms. In other cases, the presence of specific chemical species may produce toxic effects limiting growth and abundance of living matter.
Metals
Many dissolved or suspended metal salts exert harmful effects in the environment sometimes at very low concentrations. Some aquatic plants are able to remove very low metal concentrations, with the metals ending up bound to clay or other mineral particles.
Organisms
Saprophytic bacteria and fungi can convert organic matter into living cell mass, carbon dioxide, water and a range of metabolic by-products. These saprophytic organisms may then be predated upon by protozoa, rotifers and, in cleaner waters, Bryozoa which consume suspended organic particles including viruses and pathogenic bacteria. Clarity of the water may begin to improve as the protozoa are subsequently consumed by rotifers and cladocera. Purifying bacteria, protozoa, and rotifers must either be mixed throughout the water or have the water circulated past them to be effective. Sewage treatment plants mix these organisms as activated sludge or circulate water past organisms living on trickling filters or rotating biological contactors.
Aquatic vegetation may provide similar surface habitat for purifying bacteria, protozoa, and rotifers in a pond or marsh setting; although water circulation is often less effective. Plants and algae have the additional advantage of removing nutrients from the water; but some of those nutrients will be returned to the water when the plants die unless the plants are removed from the water. Because of the complex chemistry of Phosphorus much of this element is in an unavailable form unless decomposition creates anoxic conditions which render the phosphorus available for re-uptake. Plants also provide shade, a refuge for fish, and oxygen for aerobic bacteria. In addition, fish can limit pests such as mosquitoes. Fish and waterfowl feces return waste to the water, and their feeding habits may increase turbidity. Cyanobacteria have the disadvantageous ability to add nutrients from the air to the water being purified and to generate toxins in some cases.
The choice of organism depends on the local climate different species and other factors. Indigenous species usually tend to be better adapted to the local environment.
Macrophytes
The choice of plants in engineered wet-lands or managed lagoons is dependent on the purification requirements of the system and this may involve plantings of varying plant species at a range of depths to achieve the required goal.
Plants purify water by consuming excess nutrients and by providing surfaces upon which a wide range of other purifying organisms can live. They also are effective oxygenators in sunlight. They also have the ability to translocate chemicals between their submerged foliage and their root systems and this is of significance in engineered wet-lands designed to de-toxify waste waters. Plants that have been used in temperate climates include Nymphea alba, Phragmites australis, Sparganium erectum, Iris pseudacorus, Schoenoplectus lacustris and Carex acutiformis.
Where oxygenation is a critical requirement Stratiotes aloides, Hydrocharis morsus-ranae, Acorus calamus, Myriophyllum species and Elodea have been used.
Hydrocharis morsus-ranae and Nuphar lutea have been used where shade and cover are required.
Fish
Fish are frequently the top level predators in a managed treatment eco-system and in some case may simply be a mono-culture of herbivorous species. Management of multi-species fisheries requires careful management and may involve a range of fish species including bottom-feeders and predatory species to limit population growth of the herbivorous fish.
Rotifers
Rotifers are microscopic complex organisms and are filter feeders removing fine particulate matter from water. They occur naturally in aerobic lagoons, activated sludge processes, in trickling filters and in final settlement tanks and are a significant factor in removing suspended bacterial cells and algae from the water column.
Annelids
Annelid worms are essential to the effective operation of trickling filters helping to remove excess bio-mass and enhancing natural sloughing of the bio-film. Supernumerary worms are very commonly found in the drainage troughs around trickling filters and in the final settlement sludge. Annelids also play a key role in lagoon treatment systems and in the effective working or engineered wet-lands. In this environment worms are a principal force in mixing in the upper few centimetres of the sediment layer exposing organic material to both oxidative and anoxic environments aiding the complete breakdown of most organics. They are also a key ingredient in the food-chain transferring energy upwards to fish and aquatic birds.
Protozoa
The range of protozoan species found is very wide but may include species of the following genera:
Amoeba
Arcella
Blepharisma
Didinium
Euglena
Hypotrich
Paramecium
Suctoria
Stylonychia
Vorticella
Insects
Chironomidae bloodworm larva
Podura aquatica water springtail
Psychodidae drain fly or filter fly larva
Bacteria
Bacteria are probably the most significant group of organisms involved in water purification and are ubiquitous in all biological purification environments. Some such as Sphaerotilus natans are typically associated with grossly polluted waters, but even in such environments the bacteria are degrading the organic material present.
See also
Aquatic plant
Water purification
Treatment pond
Detoxification
Sources
Fair, Gordon Maskew, Geyer, John Charles & Okun, Daniel Alexander Water and Wastewater Engineering (Volume 2) John Wiley & Sons (1968)
Hammer, Mark J. Water and Waste-Water Technology John Wiley & Sons (1975)
Metcalf & Eddy Wastewater Engineering McGraw-Hill (1972)
Notes
Anaerobic digestion
Sewerage
Water technology
Water pollution
Water treatment | Organisms involved in water purification | Chemistry,Engineering,Environmental_science | 1,547 |
55,159,609 | https://en.wikipedia.org/wiki/Martha%20Krebs | Martha Krebs is a theoretical physicist who directed the Office of Science for the United States Department of Energy from 1993 to 2000. She later went on to be the founding director for the University of California, Los Angeles's California NanoSystems Institute.
Early life and education
Martha Krebs was born in Atlantic City, New Jersey. Krebs graduated summa cum laude at the Catholic University of America in 1966 with a bachelor's degree in physics. In 1975 she completed her PhD in theoretical physics, specializing in statistical mechanics at the same university.
Krebs is part of the American Physical Society, the American Association for the Advancement of Science, and the Association for Women in Science. She is also a member of Phi Beta Kappa Society.
Career
Krebs served as a member on the House Committee on Science, from 1977 through 1983. She started as a professional staff member before later becoming the subcommittee staff director. She left the committee in 1983 to become an associate director of Planning and Development for the United States Department of Energy at the Lawrence Berkeley National Laboratory. While working at the lab Krebs's role was to plan research, oversee science education and handle outreach.
Krebs switched jobs in 1993, and worked for seven years in the United States Department of Energy and the Office of Science. She was the assistant secretary and the director of the Office of Science at the Department of Energy, and was responsible for managing the $3.1 billion budget. One of her major accomplishments while working for the department was to oversee the completion of the main injector for the particle accelerator at Fermilab.
Krebs stepped down in 2000 to work on research and development management, planning and budgeting for the Institute for Defence Studies and Analyses. In 2001 she became the founding director for California NanoSystems Institute at University of California, Los Angeles. From 2005 to 2009 Krebs was the deputy director for research and development at the California Energy Commission. In 2013 she was appointed senior scientist at Penn State College of Engineering and director of the energy efficient buildings hub at the Philadelphia Naval Shipyard.
See also
Women in physics
Women in government
References
Year of birth missing (living people)
Living people
People from Atlantic City, New Jersey
Theoretical physicists
Catholic University of America alumni
20th-century United States government officials
20th-century American physicists
21st-century American scientists
Fellows of the American Physical Society | Martha Krebs | Physics | 481 |
1,209,074 | https://en.wikipedia.org/wiki/Permeance | Permeance, in general, is the degree to which a material admits a flow of matter or energy. Permeance is usually represented by a curly capital P: .
Electromagnetism
In electromagnetism, permeance is the inverse of reluctance. In a magnetic circuit, permeance is a measure of the quantity of magnetic flux for a number of current-turns. A magnetic circuit almost acts as though the flux is conducted, therefore permeance is larger for large cross-sections of a material and smaller for smaller cross section lengths. This concept is analogous to electrical conductance in the electric circuit.
Magnetic permeance is defined as the reciprocal of magnetic reluctance (in analogy with the reciprocity between electric conductance and resistance):
which can also be re-written:
using Hopkinson's law (magnetic circuit analogue of Ohm's law for electric circuits) and the definition of magnetomotive force (magnetic analogue of electromotive force):
where:
, magnetic flux,
, current, in amperes,
, winding number of, or count of turns in the electric coil.
Alternatively in terms of magnetic permeability (analogous to electric conductivity):
where:
, permeability of material,
, cross-sectional area,
ℓ, magnetic path length.
The SI unit of magnetic permeance is the henry (H), equivalently, webers per ampere.
Materials science
In materials science, permeance is the degree to which a material transmits another substance.
See also
Dielectric complex reluctance
Reluctance
Notes
References
Electromagnetism
Properties of Magnetic Materials (units of magnetic permeance)
Material science
Bombaru, D., Jutras, R., and Patenaude, A., "Air Permeance of Building Materials". Summary report prepared by, AIR-INS Inc. for Canada Mortgage and Housing Corporation, Ottawa, 1988.
Electric and magnetic fields in matter | Permeance | Physics,Chemistry,Materials_science,Engineering | 397 |
22,266,586 | https://en.wikipedia.org/wiki/Herbert%20S.%20White | Herbert Spencer White (July 5, 1927 – September 9, 2024) was an Austrian-born American librarian. He was Dean Emeritus and Distinguished Professor Emeritus at the School of Library and Information Science at Indiana University, and adjunct professor, University of Arizona, Tucson. He was honored with the Award of Merit - Association for Information Science and Technology and the American Library Association Melvil Dewey Award. He was a contributor to current theory and understanding of the role of the special library in contemporary American organizations.
Life and career
White was born in Vienna, Austria, on July 5, 1927. He had a Bachelor of Science (Chemistry) and Masters of Library Science from Syracuse University. \
He was Director of the NASA Scientific and Technical Information Facility, librarian at the Library of Congress and Atomic Energy Commission, program manager of the IBM Corporate Technical Information Center, and Vice President for Operations of the Institute for Scientific Information.
White was dean and professor from 1975-1991 at Indiana University School of Informatics Bloomington campus and distinguished Professor Emeritus after 1991.
White was the author of more than nine books and 200 articles on topics of library administration, supervision and library automation. He was a frequent speaker and presenter at seminars and workshops.
In retirement he continued adjunct teaching at the University of Arizona, writing and lecturing.
His "White Papers," a column published in Library Journal for more than a decade, was influential on current issues. Many of these popular columns were collected and republished in Librarianship Quo Vadis? (Libraries Unlimited: 2000).
White died on September 9, 2024, at the age of 97.
Selected publications
White Herbert S. (2000). Librarianship--Quo Vadis? : Opportunities and Dangers As We Face the New Millennium. Englewood Colo: Libraries Unlimited.
White Herbert S. (1995). At the Crossroads : Librarians on the Information Superhighway. Englewood Colo: Libraries Unlimited.
White Herbert S. (1993). “Rankings of Library and Information Science Faculty and Programs: The Third in a Series of Studies Undertaken at Six-Year Intervals.” Library Quarterly 166–87.
White Herbert S. (1992). Ethical Dilemmas in Libraries: A Collection of Case Studies. New York Toronto New York: G.K. Hall ; Maxwell Macmillan Canada ; Maxwell Macmillan International.
White, Herbert S. (1989). “The Danger of Political Polarization for Librarianship.” Library Journal 114 (11): 40–41.
White Herbert S. (1989). Librarians and the Awakening from Innocence: A Collection of Papers. Boston Mass: G.K. Hall.
White, Herbert S. (1987). “The Funding of Corporate Libraries—old Myths and New Problems.” Special Libraries 78 (July): 155–61.
White Herbert S. (1984). Managing the Special Library: Strategies for Success Within the Larger Organization. White Plains NY: Knowledge Industry Publications.
Awards and honors
Festschrift in Honour of Herbert S. White. (1993).
Awarded title of Distinguished Professor at Indiana University (1991).
Melvil Dewey Medal by the American Library Association (1987).
American Society for Information Science Award of Merit. (1981).
References
"Introducing Herbert S. White" Current Contents (ISI) #3, January 26, 1972:
External links
Official Biography at Indiana University
LibraryThing book list (partial)
(very partial)
1927 births
2024 deaths
City College of New York alumni
Syracuse University alumni
Indiana University faculty
University of Arizona faculty
American librarians
People from Vienna
Information science awards
Information scientists | Herbert S. White | Technology | 721 |
1,049,151 | https://en.wikipedia.org/wiki/Wangar%C4%A9%20Maathai | Wangarĩ Maathai (; 1 April 1940 – 25 September 2011) was a Kenyan social, environmental, and political activist who founded the Green Belt Movement, an environmental non-governmental organization focused on the planting of trees, environmental conservation, and women's rights. In 2004 she became the first African woman to win the Nobel Peace Prize.
As a beneficiary of the Kennedy Airlift, she studied in the United States, earning a bachelor's degree from Mount St. Scholastica and a master's degree from the University of Pittsburgh. She went on to become the first woman in East and Central Africa to become a Doctor of Philosophy, receiving her Ph.D. from the University of Nairobi in Kenya. In 1984, she got the Right Livelihood Award for "converting the Kenyan ecological debate into mass action for reforestation." Wangari Maathai was an elected member of the Parliament of Kenya and, between January 2003 and November 2005, served as Assistant Minister for Environment and Natural Resources in the government of President Mwai Kibaki. She was an Honorary Councillor of the World Future Council. As an academic and the author of several books, Maathai was not only an activist but also an intellectual who has made significant contributions to thinking about ecology, development, gender, and African cultures and religions.
Maathai died of complications from ovarian cancer on 25 September 2011.
Early life and education
Maathai was born on 1 April 1940 in the village of Ihithe, Nyeri District, in the central highlands of the colony of Kenya. Her family was Kikuyu, the most populous ethnic group in Kenya, and had lived in the area for several generations. Around 1943, Maathai's family relocated to a white-owned farm in the Rift Valley, near Nakuru, where her father had found work. Late in 1947, she returned to Ihithe with her mother, as two of her brothers were attending primary school in the village, and there was no schooling available on the farm where her father worked. Her father remained at the farm. Shortly afterward, at the age of eight years, she joined her brothers at Ihithe Primary School.
At eleven years, Maathai moved to St. Cecilia's Intermediate Primary School, a boarding school at the Mathari Catholic Mission in Nyeri. Maathai studied at St. Cecilia's for four years. During this time, she became fluent in English and converted to Catholicism. She was involved with the Legion of Mary, whose members attempted "to serve God by serving fellow human beings." Studying at St. Cecilia's, she was sheltered from the ongoing Mau Mau uprising, which forced her mother to move from their homestead to an emergency village in Ihithe. When she completed her studies there in 1956, she was rated first in her class, and was granted admission to the only Catholic high school for girls in Kenya, Loreto High School in Limuru.
As the end of East African colonialism approached, Kenyan politicians, such as Tom Mboya, were proposing ways to make education in Western nations available to promising students. John F. Kennedy, then a United States senator, agreed to fund such a program through the Joseph P. Kennedy Jr. Foundation, initiating what became known as the Kennedy Airlift or Airlift Africa. Maathai became one of some 300 Kenyans selected to study in the United States in September 1960.
She received a scholarship to study at Mount St. Scholastica College (now Benedictine College), in Atchison, Kansas, where she majored in biology, with minors in chemistry and German. After receiving her Bachelor of Science degree in 1964, she studied at the University of Pittsburgh for a master's degree in biology. Her graduate studies there were funded by the Africa-America Institute, and during her time in Pittsburgh, she first experienced environmental restoration, when local environmentalists pushed to rid the city of air pollution. In January 1966, Maathai received her MSc in biological sciences, and was appointed to a position as research assistant to a professor of zoology at University College of Nairobi.
Upon returning to Kenya, Maathai dropped her forename, preferring to be known by her birth name, Wangarĩ Muta. When she arrived at the university to start her new job, she was informed that it had been given to someone else. Maathai believed this was because of gender and tribal bias. After a two-month job search, Professor Reinhold Hofmann, from the University of Giessen in Germany, offered her a job as a research assistant in the microanatomy section of the newly established Department of Veterinary Anatomy in the School of Veterinary Medicine at the University College of Nairobi. In April 1966, she met Mwangi Mathai, another Kenyan who had studied in America, who would later become her husband. She also rented a small shop in the city and established a general store, at which her sisters worked. In 1967, at the urging of Professor Hofmann, she travelled to the University of Giessen in Germany in pursuit of a doctorate. She studied both at Giessen and the University of Munich.
In the spring of 1969, she returned to Nairobi to continue her studies at the University College of Nairobi as an assistant lecturer. In May, she and Mwangi Mathai married. Later that year, she became pregnant with her first child, and her husband campaigned for a seat in Parliament, narrowly losing. During the election, Tom Mboya, who had been instrumental in founding the program which sent her overseas, was assassinated. This led to President Kenyatta effectually ending multi-party democracy in Kenya. Shortly after, her first son, Waweru, was born. In 1971, she became the first Eastern African woman to receive a Ph.D., her doctorate in veterinary anatomy, from the University College of Nairobi, which became the University of Nairobi the following year. She completed her dissertation on the development and differentiation of gonads in bovines. Her daughter, Wanjira, was born in December 1971.
Activism and political life
1972–1977: Start of activism
Maathai continued to teach at Nairobi, becoming a senior lecturer in anatomy in 1975, chair of the Department of Veterinary Anatomy in 1976, and associate professor in 1977. She was the first woman in Nairobi appointed to any of these positions. During this time, she campaigned for equal benefits for the women working on the staff of the university, going so far as trying to turn the academic staff association of the university into a union, to negotiate for benefits. The courts denied this bid, but many of her demands for equal benefits were later met. In addition to her work at the University of Nairobi, Maathai became involved in several civic organisations in the early 1970s. She was a member of the Nairobi branch of the Kenya Red Cross Society, becoming its director in 1973. She was a member of the Kenya Association of University Women. Following the establishment of the Environment Liaison Centre in 1974, Maathai was asked to be a member of the local board, eventually becoming board chair. The Environment Liaison Centre worked to promote the participation of non-governmental organisations in the work of the United Nations Environment Programme (UNEP), whose headquarters was established in Nairobi following the United Nations Conference on the Human Environment held in Stockholm in 1972. Maathai also joined the National Council of Women of Kenya (NCWK). Through her work at these various volunteer associations, it became evident to Maathai that the root of most of Kenya's problems was environmental degradation.
In 1974, Maathai's family expanded to include her third child, son Muta. Her husband campaigned again for a seat in Parliament, hoping to represent the Lang'ata constituency, and won. During his campaign, he had promised to find jobs to limit the rising unemployment in Kenya. These promises led Maathai to connect her ideas of environmental restoration to providing jobs for the unemployed and led to the founding of Envirocare Ltd., a business that involved the planting of trees to conserve the environment, involving ordinary people in the process. This led to the planting of her first tree nursery, collocated with a government tree nursery in Karura Forest. Envirocare ran into multiple problems, primarily dealing with funding, and ultimately failed. However, through conversations concerning Envirocare and her work at the Environment Liaison Centre, UNEP made it possible to send Maathai to the first UN conference on human settlements, known as Habitat I, in June 1976.
In 1977, Maathai spoke to the NCWK concerning her attendance at Habitat I. She proposed further tree planting, which the council supported. On 5 June 1977, marking World Environment Day, the NCWK marched in a procession from Kenyatta International Conference Centre in downtown Nairobi to Kamukunji Park on the outskirts of the city, where they planted seven trees in honour of historical community leaders. This was the first event of the Green Belt Movement. Maathai encouraged the women of Kenya to plant tree nurseries throughout the country, searching nearby forests for seeds to grow trees native to the area. She agreed to pay the women a small stipend for each seedling which was later planted elsewhere.
In her 2010 book, Replenishing the Earth: Spiritual Values for Healing Ourselves and the World, she discussed the impact of the Green Belt Movement, explaining that the group's civic and environmental seminars stressed "the importance of communities taking responsibility for their actions and mobilizing to address their local needs," and adding, "We all need to work hard to make a difference in our neighborhoods, regions, and countries, and in the world as a whole. That means making sure we work hard, collaborate, and make ourselves better agents to change." In this book, she explicitly engages with religious traditions, including the indigenous Kikuyu religion and Christianity, mobilizing them as resources for environmental thinking and activism.
1977–1979: Personal problems
Maathai and her husband, Mwangi Mathai, separated in 1977. After a lengthy separation, Mwangi filed for divorce in 1979. He was said to have believed that Wangari was "too strong-minded for a woman" and that he was "unable to control her". In addition to naming her as "cruel" in court filings, he publicly accused her of adultery with another Member of Parliament, which in turn was thought to cause his high blood pressure and the judge ruled in Mwangi's favour. Shortly after the trial, in an interview with Viva magazine, Maathai referred to the judge as either incompetent or corrupt. The interview later led the judge to charge Maathai with contempt of court. She was found guilty and sentenced to six months in jail. After three days in Lang'ata Women's Prison in Nairobi, her lawyer formulated a statement that the court found sufficient for her release. Shortly after the divorce, her former husband sent a letter via his lawyer demanding that Maathai drop his surname. She chose to add an extra "a" instead of changing her name.
The divorce had been costly, and with lawyers' fees and the loss of her husband's income, Maathai found it difficult to provide for herself and their children on her university wages. An opportunity arose to work for the Economic Commission for Africa through the United Nations Development Programme. As this job required extended travel throughout Africa and was based primarily in Lusaka, Zambia, she was unable to bring her children with her. Maathai chose to send them to her ex-husband and take the job. While she visited them regularly, they lived with their father until 1985.
1979–1982: Political problems
In 1979, shortly after the divorce, Maathai ran for the position of chairperson of the National Council of Women of Kenya (NCWK), an umbrella organisation consisting of many women's organisations in the country. The newly-elected President of Kenya, Daniel arap Moi, tried to limit the amount of influence those of the Kikuyu ethnicity held in the country, including in volunteer civic organisations such as the NCWK. She lost this election by three votes, but was overwhelmingly chosen to be the vice-chairman of the organisation. The following year, Maathai again ran for chairman of the NCWK. Again she was opposed, she believes, by the government. When it became apparent that Maathai was going to win the election, Maendeleo Ya Wanawake, a member organisation which represented a majority of Kenya's rural women and whose leader was close to Arap Moi, withdrew from the NCWK. Maathai was then elected chairman of the NCWK unopposed. However, Maendeleo Ya Wanawake came to receive a majority of the financial support for women's programs in the country, and NCWK was left virtually bankrupt. Future funding was much more difficult to come by, but the NCWK survived by increasing its focus on the environment and making its presence and work known. Maathai continued to be reelected to serve as chairman of the organization every year until she retired from the position in 1987.
In 1982, the Parliamentary seat representing her home region of Nyeri was open, and Maathai decided to campaign for the seat. As required by law, she resigned from her position with the University of Nairobi to campaign for office. The courts decided that she was ineligible to run for office because she had not re-registered to vote in the last presidential election in 1979. Maathai believed this to be false and illegal, and brought the matter to court. The court was to meet at nine in the morning, and if she received a favorable ruling, was required to present her candidacy papers in Nyeri by three in the afternoon that day. The judge disqualified her from running on a technicality: as before, they claimed she should have re-registered to vote. When she requested her job back, she was denied. As she lived in university housing and was no longer a staff member, she was evicted.
Green Belt Movement
Maathai founded the Green Belt Movement in 1977 in response to the environmental concerns raised by rural Kenyan women. She moved into a small home she had purchased years before, and focused on the NCWK before becoming employed again. In the course of her work through the NCWK, she had the opportunity to partner with the executive director of the Norwegian Forestry Society, Wilhelm Elsrud. Maathai became the coordinator. Along with the partnership with the Norwegian Forestry Society, the movement had also received "seed money" from the United Nations Voluntary Fund for Women. These funds allowed for the expansion of the movement, for hiring additional employees to oversee the operations, and for continuing to pay a small stipend to the women who planted seedlings throughout the country. It allowed her to refine the operations of the movement, paying a small stipend to the women's husbands and sons who were literate and able to keep accurate records of seedlings planted.
The UN held the third global women's conference in Nairobi. During the conference, Maathai arranged seminars and presentations to describe the work the Green Belt Movement was doing in Kenya. She escorted delegates to see nurseries and plant trees. She met Peggy Snyder, the head of UNIFEM, and Helvi Sipilä, the first woman appointed a UN assistant secretary general. The conference helped to expand funding for the Green Belt Movement and led to the movement's establishing itself outside Kenya. In 1986, with funding from UNEP, the movement expanded throughout Africa and led to the foundation of the Pan-African Green Belt Network. Forty-five representatives from fifteen African countries travelled to Kenya over the next three years to learn how to set up similar programs in their own countries to combat desertification, deforestation, water crises, and rural hunger. The attention the movement received in the media led to Maathai's being honored with numerous awards. The government of Kenya, however, demanded that the Green Belt Movement separate from the NCWK, believing the latter should focus solely on women's issues, not the environment. Therefore, in 1987, Maathai stepped down as chairperson of the NCWK and focused on the newly separate non-governmental organisation.
Government intervention
In the latter half of the 1980s, the Kenyan government came down against Maathai and the Green Belt Movement. The single-party regime opposed many of the movement's positions regarding democratic rights. The government invoked a colonial-era law prohibiting groups of more than nine people from meeting without a government license. In 1988, the Green Belt Movement carried out pro-democracy activities such as registering voters for the election and pressing for constitutional reform and freedom of expression. The government carried out electoral fraud in the elections to maintain power, according to Maathai.
In October 1989, Maathai learned of a plan to construct the 60-storey Kenya Times Media Trust Complex in Uhuru Park. The complex was intended to house the headquarters of KANU, the Kenya Times newspaper, a trading center, offices, an auditorium, galleries, shopping malls, and parking spaces for 2,000 cars. The plan also included a large statue of President Daniel Arap Moi. Maathai wrote many letters in protest to, among others, the Kenya Times, the Office of the President, the Nairobi city commission, the provincial commissioner, the minister for environment and natural resources, the executive directors of UNEP and the Environment Liaison Centre International, the executive director of the United Nations Educational, Scientific and Cultural Organization (UNESCO), the ministry of public works, and the permanent secretary in the department of international security and administration all received letters. She wrote to Sir John Johnson, the British high commissioner in Nairobi, urging him to intervene with Robert Maxwell, a major shareholder in the project, equating the construction of a tower in Uhuru Park to such construction in Hyde Park or Central Park and maintaining that it could not be tolerated.
The government refused to respond to her inquiries and protests, instead responding through the media that Maathai was "a crazy woman"; that denying the project in Uhuru Park would take more than a small portion of public parkland; and proclaiming the project as a "fine and magnificent work of architecture" opposed by only the "ignorant few". On 8 November 1989, Parliament expressed outrage at Maathai's actions, complaining of her letters to foreign organisations and calling the Green Belt Movement a bogus organisation and its members "a bunch of divorcees". They suggested that if Maathai was so comfortable writing to Europeans, perhaps she should go live in Europe.
Despite Maathai's protests, as well as popular protest growing throughout the city, the ground was broken at Uhuru Park for construction of the complex on 15 November 1989. Maathai sought an injunction in the Kenya High Court to halt construction, but the case was thrown out on 11 December. In his first public comments peonhe project, President Daniel Arap Moi stated that those who opposed the project had "insects in their heads". On 12 December, in Uhuru Park, during a speech celebrating independence from the British, President Moi suggested Maathai be a proper woman in the African tradition and respect men and be quiet. She was forced by the government to vacate her office, and the Green Belt Movement was moved into her home. The government audited the Green Belt Movement in an apparent attempt to shut it down. Despite the government's efforts, her protests and the media coverage the government's response garnered led foreign investors to cancel the project in January 1990.
In January 1992, it came to the attention of Maathai and other pro-democracy activists that a list of people were targeted for assassination and that a government-sponsored coup was possible. Maathai's name was on the list. The pro-democracy group, known as the Forum for the Restoration of Democracy (FORD), presented its information to the media, calling for a general election. Later that day, Maathai received a warning that one of their members had been arrested. Maathai decided to barricade herself in her home. Shortly thereafter, police arrived and surrounded the house. She was besieged for three days before police cut through the bars she had installed on her windows, came in, and arrested her. She and the other pro-democracy activists who had been arrested were charged with spreading malicious rumors, sedition, and treason. After a day and a half in jail, they were brought to a hearing and released on bail. A variety of international organisations and eight senators (including Al Gore and Edward M. Kennedy) put pressure on the Kenyan government to substantiate the charges against the pro-democracy activists or risk damaging relations with the United States. In November 1992, the Kenyan government dropped the charges.
On 28 February 1992, while released on bail, Maathai and others took part in a hunger strike in a corner of Uhuru Park, which they labeled Freedom Corner, to pressure the government to release political prisoners. After four days of hunger strike, on 3 March 1992, the police forcibly removed the protesters. Maathai and three others were knocked unconscious by police and hospitalized. President Daniel arap Moi called her "a mad woman" and "a threat to the order and security of the country". The attack drew international criticism. The US State Department said it was "deeply concerned" by the violence and by the forcible removal of the hunger strikers. When the prisoners were not released, the protesters – mostly mothers of those in prison – moved their protest to All Saints Cathedral, the seat of the Anglican Archbishop in Kenya, across from Uhuru Park. The protest there continued, with Maathai contributing frequently, until early 1993 when the prisoners were finally released.
During this time, Maathai was recognized with various awards internationally, but the Kenyan government did not appreciate her work. In 1991 she received the Goldman Environmental Prize in San Francisco and the Hunger Project's Africa Prize for Leadership in London. CNN aired a three-minute segment about the Goldman prize, but when it aired in Kenya, that segment was cut out. In June 1992, during the long protest at Uhuru Park, both Maathai and President arap Moi travelled to Rio de Janeiro for the UN Conference on Environment and Development (Earth Summit). The Kenyan government accused Maathai of inciting women and encouraging them to strip at Freedom Corner, urging that she not be allowed to speak at the summit. Despite this, Maathai was chosen to be a chief spokesperson at the summit.
Push for democracy
During the first multi-party election of Kenya, in 1992, Maathai strove to unite the opposition and for fair elections in Kenya. The Forum for the Restoration of Democracy (FORD) had fractured into FORD-Kenya (led by Oginga Odinga) and FORD-Asili (led by Kenneth Matiba); former vice president Mwai Kibaki had left the ruling Kenya African National Union (KANU) party, and formed the Democratic Party. Maathai and many others believed such a fractured opposition would lead to KANU's retaining control of the country, so they formed the Middle Ground Group in an effort to unite the opposition. Maathai was chosen to serve as its chairperson. Also during the election, Maathai and like-minded opposition members formed the Movement for Free and Fair Elections. Despite their efforts, the opposition did not unite, and the ruling KANU party used intimidation and state-held media to win the election, retaining control of parliament.
The following year, ethnic clashes occurred throughout Kenya. Maathai believed they were incited by the government, who had warned of stark consequences to multi-party democracy. Maathai travelled with friends and the press to areas of violence in order to encourage them to cease fighting. With the Green Belt Movement she planted "trees of peace", but before long her actions were opposed by the government. The conflict areas were labeled as "no go zones", and in February 1993 the president claimed that Maathai had masterminded a distribution of leaflets inciting Kikuyus to attack Kalenjins. After her friend and supporter Dr. Makanga was kidnapped, Maathai chose to go into hiding. While in hiding, Maathai was invited to a meeting in Tokyo of the Green Cross International, an environmental organisation recently founded by former Soviet leader Mikhail Gorbachev. When Maathai responded that she could not attend as she did not believe the government would allow her to leave the country and she was in hiding, Gorbachev pressured the government of Kenya to allow her to travel freely. President arap Moi denied limiting her travel, and she was allowed to leave the country, although too late for the meeting in Tokyo. Maathai was again recognized internationally, and she flew to Scotland to receive the Edinburgh Medal in April 1993. In May she went to Chicago to receive the Jane Addams International Women's Leadership Award, and in June she attended the UN's World Conference on Human Rights in Vienna.
During the elections of 1997, Maathai again wished to unite the opposition in order to defeat the ruling party. In November, less than two months before the election, she decided to run for parliament and for president as a candidate of the Liberal Party. Her intentions were widely questioned in the press; many believed she should simply stick to running the Green Belt Movement and stay out of politics. On the day of the election, a rumour that Maathai had withdrawn from the election and endorsed another candidate was printed in the media. Maathai garnered few votes and lost the election.
In the summer of 1998, Maathai learned of a government plan to privatize large areas of public land in the Karura Forest, just outside Nairobi, and give it to political supporters. Maathai protested this through letters to the government and the press. She went with the Green Belt Movement to Karura Forest, planting trees and protesting the destruction of the forest. On 8 January 1999, a group of protesters including Maathai, six opposition MPs, journalists, international observers, and Green Belt members and supporters returned to the forest to plant a tree in protest. The entry to the forest was guarded by a large group of men. When she tried to plant a tree in an area that had been designated to be cleared for a golf course, the group was attacked. Many of the protesters were injured, including Maathai, four MPs, some of the journalists, and German environmentalists. When she reported the attack to the police, they refused to return with her to the forest to arrest her attackers. However, the attack had been filmed by Maathai's supporters, and the event provoked international outrage. Student protests broke out throughout Nairobi, and some of these groups were violently broken up by the police. Protests continued until 16 August 1999, when the president announced that he was banning all allocation of public land.
In 2001, the government again planned to take public forest land and give it to its supporters. While protesting this and collecting petition signatures on 7 March 2001, in Wang'uru village near Mount Kenya, Maathai was again arrested. The following day, following international and popular protest at her arrest, she was released without being charged. On 7 July 2001, shortly after planting trees at Freedom Corner in Uhuru Park in Nairobi to commemorate Saba Saba Day, Maathai was again arrested. Later that evening, she was again released without being charged. In January 2002, Maathai returned to teaching as the Dorothy McCluskey Visiting Fellow for Conservation at the Yale University's School of Forestry and Environmental Studies. She remained there until June 2002, teaching a course on sustainable development focused on the work of the Green Belt Movement.
Election to parliament
Upon her return to Kenya, Maathai again campaigned for parliament in the 2002 elections, this time as a candidate of the National Rainbow Coalition, the umbrella organisation which finally united the opposition. On 27 December 2002, the Rainbow Coalition defeated the ruling party Kenya African National Union, and in Tetu Constituency Maathai won with an overwhelming 98% of the vote. In January 2003, she was appointed Assistant Minister in the Ministry for Environment and Natural Resources and served in that capacity until November 2005. She founded the Mazingira Green Party of Kenya in 2003 to allow candidates to run on a platform of conservation as embodied by the Green Belt Movement. It is a member of the Federation of Green Parties of Africa and the Global Greens.
2004 Nobel Peace Prize
Wangarĩ Maathai was awarded the 2004 Nobel Peace Prize for her "contribution to sustainable development, democracy and peace." Maathai was the first African woman to win the prestigious award. According to Nobel's will, the Peace Prize shall be awarded to the person who in the preceding year "shall have done the most or the best work for fraternity between nations, for the abolition or reduction of standing armies and for the holding and promotion of peace congresses". Between 1901 and 2018, only 52 Nobel Prize awards were given to women, while 852 Nobel Prize awards have been given to men. Through her significant efforts, Wangari Maathai became the first African woman, and the first environmentalist, to win the Peace Prize.
AIDS conspiracy theory
Controversy arose when it was reported by Kenyan newspaper The Standard that Maathai had claimed HIV/AIDS was "deliberately created by Western scientists to decimate the African population." Maathai denied making the allegations, but The Standard has stood by its reports.
In a 2004 interview with Time magazine, in response to questions concerning that report, Maathai replied: "I have no idea who created AIDS and whether it is a biological agent or not. But I do know things like that don't come from the moon. I have always thought that it is important to tell people the truth, but I guess there is some truth that must not be too exposed," and when asked what she meant, she continued, "I'm referring to AIDS. I am sure people know where it came from. And I'm quite sure it did not come from the monkeys." In response she issued the following statement:
2005–2011: Later life
Following a trip to Japan in 2005, Maathai became an enthusiastic proponent of the waste-reduction philosophy of mottainai, a Japanese term of Buddhist origin.
On 28 March 2005, Maathai was elected the first president of the African Union's Economic, Social and Cultural Council and was appointed a goodwill ambassador for an initiative aimed at protecting the Congo Basin Forest Ecosystem. In 2006, she was one of the eight flag-bearers at the 2006 Winter Olympics Opening Ceremony. Also on 21 May 2006, she was awarded an honorary doctorate by and gave the commencement address at Connecticut College. She supported the International Year of Deserts and Desertification program. In November 2006, she spearheaded the United Nations Billion Tree Campaign. Maathai was one of the founders of the Nobel Women's Initiative along with sister Nobel Peace laureates Jody Williams, Shirin Ebadi, Rigoberta Menchú Tum, Betty Williams and Mairead Corrigan Maguire. Six women representing North America and South America, Europe, the Middle East and Africa decided to bring together their experiences in a united effort for peace with justice and equality. It is the goal of the Nobel Women's Initiative to help strengthen work being done in support of women's rights around the world.
In August 2006, then United States Senator Barack Obama traveled to Kenya. His father was educated in America through the same program as Maathai. She and the Senator met and planted a tree together in Uhuru Park in Nairobi. Obama called for freedom of the press to be respected, saying, "Press freedom is like tending a garden; it continually has to be nurtured and cultivated. The citizenry has to value it because it's one of those things that can slip away if we're not vigilant." He deplored global ecological losses, singling out President George W. Bush's refusal to join the United Nations Framework Convention on Climate Change (UNFCCC) and its subsidiary, the Kyoto Protocol.
Maathai was defeated in the Party of National Unity's primary elections for its parliamentary candidates in November 2007 and chose to instead run as the candidate of a smaller party. She was defeated in the December 2007 parliamentary election. She called for a recount of votes in the presidential election (officially won by Mwai Kibaki, but disputed by the opposition) in her constituency, saying that both sides should feel the outcome was fair and that there were indications of fraud.
In 2009, she published "The Challenge for Africa" with her insights into the strengths and weaknesses of governance in Africa, her own experiences, and the centrality of environmental protection to Africa's future.
In June 2009, Maathai was named as one of PeaceByPeace.com's first peace heroes. Until her death in 2011, Maathai served on the Eminent Advisory Board of the Association of European Parliamentarians with Africa (AWEPA).
Wangarĩ Maathai died on 25 September 2011 of complications arising from ovarian cancer while receiving treatment at a Nairobi hospital.
Her remains were cremated and buried at the Wangari Maathai Institute for Peace and Environmental Studies in Nairobi.
Wangarĩ Maathai Forest Champion Award
In 2012, the Collaborative Partnership on Forests CPF, an international consortium of 14 organisations, secretariats and institutions working on international forest issues, launched the inaugural Wangarĩ Maathai Forest Champion Award.
Winners have included:
2012 – Narayan Kaji Shrestha, with an honourable mention to Kurshida Begum
2014 – Martha Isabel "Pati" Ruiz Corzo, with an honourable mention to Chut Wutty
2015 – Gertrude Kabusimbi Kenyangi
2017 – Maria Margarida Ribeiro da Silva, a Brazilian forestry activist
2019 – Léonidas Nzigiyimpa, a Burundian forestry activist
2022 – Cécile Ndjebet, a Cameroonian activist
Posthumous recognition
In 2012, Wangarĩ Gardens opened in Washington, DC. Wangarĩ Gardens is 2.7 acre community garden project for local residents which consists of over 55 garden allotments. This community garden honours the legacy of Wangarĩ Maathai and her mission for community engagement and environmental protection. The Wangarĩ Gardens consist of a community garden, youth garden, outdoor classroom, pollinator hive and public fruit tree orchard, vegetable garden, herb garden, berry garden and strawberry patch. Within the garden complex there are personal garden plots and public gardens. The personal plots are available to residents living within 1.5 miles of the community garden. Personal plot holders are required to contribute 1 hour monthly to the maintenance of the public gardens. The public gardens and orchard are maintained by plot holders and volunteers, and are open to everyone to enjoy and harvest. The Wangarĩ Gardens has no direct affiliation with the Green Belt Movement or the Wangarĩ Maathai Foundation but was inspired by Wangarĩ Maathai and her work and passion for the environment.
On 25 September 2013, the Wangarĩ Maathai Trees and Garden was dedicated on the lawn of the University of Pittsburgh's Cathedral of Learning. The memorial includes two red maples symbolizing Maathai's "commitment to the environment, her founding of the Green Belt Movement, and her roots in Kenya and in Pittsburgh" and a flower garden planted in a circular shape that representing her "global vision and dedication to the women and children of the world" with an ornamental maple tree in the middle signifying "how one small seed can change the world".
On 1 April 2013, Google celebrated Wangari Maathai’s 73rd Birthday with a doodle.
In 2014, at what would have been her 50-year reunion, her Mount St. Scholastica classmates and Benedictine College unveiled a statue of the Nobel laureate at her alma mater's Atchison, Kansas campus. In 2019, with the renovation of the Westerman Hall of Science and Engineering, the college added a mural of Maathai and other scientists to the front entryway of the building.
In 2015, UNESCO published the graphic novel Wangari Maathai and the Green Belt Movement as part of their UNESCO Series on Women in African History. As an artistic and visual interpretation intended for private or public use in classrooms, it tells the story of Maathai and the movement she started.
In October 2016, Forest Road in Nairobi was renamed to Wangarĩ Maathai Road for her efforts to oppose several attempts to degrade forests and public parks through the Green Belt Movement.
In September 2022, Washington, DC–based educational publisher, Science Naturally, included Dr. Maathai in their Women in Botany book in the Science Wide Open series for children. Brief excerpt:"Dr. Wangari started the Green Belt Movement to change things. She taught women in Kenya how to grow trees from seeds, and the women were paid to plant trees all around the country."
Selected publications
; (1985)
The bottom is heavy too: even with the Green Belt Movement : the Fifth Edinburgh Medal Address (1994)
Bottle-necks of development in Africa (1995)
The Canopy of Hope: My Life Campaigning for Africa, Women, and the Environment (2002)
Unbowed: A Memoir (2006)
Reclaiming rights and resources women, poverty and environment (2007)
Rainwater Harvesting (2008)
State of the world's minorities 2008: events of 2007 (2008)
; (2009)
Moral Ground: Ethical Action for a Planet in Peril. (2010) chapter Nelson, Michael P. and Kathleen Dean Moore (eds.). Trinity University Press,
Replenishing the Earth (2010)
Honours
1984: Right Livelihood Award
1986: Better World Society
1987: Global 500 Roll of Honour
1991: Goldman Environmental Prize
1991: The Hunger Project's Africa Prize for Leadership
1993: Edinburgh Medal (for "Outstanding contribution to Humanity through Science")
1993: Jane Addams Leadership Award
1993: Benedictine College Offeramus Medal
1994: The Golden Ark Award
2001: The Juliet Hollister Award
2003: Global Environment Award, World Association of Non-Governmental Organizations
2004: Conservation Scientist Award from Columbia University
2004: J. Sterling Morton Award
2004: Petra Kelly Prize
2004: Sophie Prize
2004: Nobel Peace Prize
2006: Légion d'honneur
2006: Doctor of Public Service (honorary degree), University of Pittsburgh
2007: World Citizenship Award
2007: Livingstone Medal from Royal Scottish Geographical Society
2007: Indira Gandhi Prize
2007: Cross of the Order of St. Benedict
2008: The Elizabeth Blackwell Award from Hobart and William Smith Colleges
2009: NAACP Image Award - Chairman's Award (with Al Gore)
2009: Grand Cordon of the Order of the Rising Sun of Japan
2011: The Nichols-Chancellor's Medal awarded by Vanderbilt University
2013: Doctor of Science (honorary degree), Syracuse University, New York
2020: The Perfect World Award by The Perfect World Foundation
See also
Black Nobel Prize laureates
List of female Nobel laureates
List of peace activists
Mottainai
Tokyo International Conference on African Development (TICAD-IV), 2008.
Women's Environment & Development Organization
References
Works cited
Further reading
Namulundah Florence, Wangari Maathai: Visionary, Environmental Leader, Political Activist, Lantern, 2015.
Wangari Maathai, The Greenbelt Movement: Sharing the Approach and the Experience, Lantern Books, 2003.
Wangari Maathai, The Canopy of Hope: My Life Campaigning for Africa, Women, and the Environment, Lantern Books, 2002.
Wangari Maathai, Bottom is Heavy Too: Edinburgh Medal Lecture, Edinburgh UP, 1994.
Picture book (fr.), Franck Prévot (text) & Aurélia Fronty (illustrations), Wangari Maathai, la femme qui plante des millions d'arbres, , 2011 ()
External links
Taking Root: The Vision of Wangari Maathai documentary film
Official Site: The Wangari Maathai Foundation
The Green Belt Movement and Wangari Maathai
Wangari Maathai and the Billion Tree Campaign
Feature on Wangari Maathai by the International Museum of Women
Seeds of change planting a path to peace
Nobel Women's Initiative
1940 births
2011 deaths
20th-century Kenyan women scientists
20th-century Kenyan scientists
Benedictine College alumni
Deaths from cancer in Kenya
Converts to Roman Catholicism
Kenyan Roman Catholics
Deaths from ovarian cancer
Economic, Social and Cultural Council officials
Nobel Peace Prize laureates
Kenyan Nobel laureates
Kenyan environmentalists
Kenyan women environmentalists
Kenyan democracy activists
Kenyan expatriates in the United States
Kenyan feminists
Kenyan veterinarians
21st-century Kenyan women politicians
21st-century Kenyan politicians
Kenyan women's rights activists
Kikuyu people
Mazingira Green Party of Kenya politicians
Members of the National Assembly (Kenya)
Grand Cordons of the Order of the Rising Sun
People from Nyeri County
University of Pittsburgh alumni
Women Nobel laureates
University of Nairobi alumni
Yale University faculty
Forestry in Kenya
Women in forestry
Candidates for President of Kenya
Japan–Kenya relations
Nonviolence advocates
Goldman Environmental Prize awardees
Environmental justice scholars
21st-century Kenyan scientists | Wangarĩ Maathai | Technology | 8,398 |
17,886,322 | https://en.wikipedia.org/wiki/Kentucky%20Space%20Grant%20Consortium | The Kentucky Space Grant Consortium (KSGC) is a partnership between Kentucky and NASA. Projects include the University of Kentucky's Big Blue, Kentucky Space, and Northern Kentucky University's Moon Buggy Project.
See also
National Space Grant College and Fellowship Program
External links
Educational organizations based in the United States
Non-profit organizations based in Kentucky
NASA programs
University of Kentucky | Kentucky Space Grant Consortium | Astronomy | 74 |
38,289,494 | https://en.wikipedia.org/wiki/Microcosm%20%28hypermedia%20system%29 | Microcosm was a hypermedia system, originally developed in 1988 by the Department of Electronics and Computer Science at the University of Southampton, with a small team of researchers in the Computer Science group: Wendy Hall, Andrew Fountain, Hugh Davis and Ian Heath. The system pre-dates the web and builds on early hypermedia systems, such as Ted Nelson's Project Xanadu and work of Douglas Engelbart. And like Intermedia or Hyper-G, which were other hypermedia systems created around the same time, Microcosm stores links between documents in a separate database.
See also
Xanadu
Intermedia
Hyper-G (or HyperWave)
References
External links
Microcosm page from W3C Historical Archives
Microcosm: an open hypermedia system (1992): Hugh Davis's video demonstration of Microcosm hypermedia features from University of Southampton
Microcosm in Vision and Reality of Hypertext and Graphical User Interfaces
Computer-related introductions in 1988
History of computing in the United Kingdom
Hypermedia
Science and technology in Hampshire
University of Southampton | Microcosm (hypermedia system) | Technology | 215 |
4,639,166 | https://en.wikipedia.org/wiki/Pipeflow | In hydrology, pipeflow is a type of subterranean water flow where water travels along cracks in the soil or old root systems found in above ground vegetation.
In such soils which have a high vegetation content water is able to travel along the 'pipes', allowing water to travel faster than throughflow. Here, water can move at speeds between 50 and 500 m/h.
References
Hydrology
Aquatic ecology | Pipeflow | Chemistry,Engineering,Biology,Environmental_science | 82 |
42,003,438 | https://en.wikipedia.org/wiki/Deuterium%20bromide | Deuterium bromide is hydrogen bromide with the hydrogen being the heavier isotope deuterium. Hydrogen represents only a small fraction of the mass so it is not significantly heavier than typical hydrogen bromide.
See also
Hydrogen bromide
Heavy water (Water with deuterium in place of normal hydrogens.)
References
Bromides | Deuterium bromide | Chemistry | 68 |
22,302,175 | https://en.wikipedia.org/wiki/Integration%20platform | An integration platform is software which integrates different applications and services. It differentiates itself from the enterprise application integration which has a focus on supply chain management. It uses the idea of system integration to create an environment for engineers.
Integration platforms can be built from components, purchased as a pre-built product ready for installation or procured from an integration Platform as a Service (iPaaS) company.
Overview
An integration platform tries to create an environment in which engineers can:
Data (information) integration: Ensure that they are using the same datasets and can share information. Data management with metadata information and versioning ensures the data is kept consistent.
Integrate many kinds of applications (independent from platform, programming language or resource) so they can be bound together in workflows and processes to work in conjunction. The different interfaces are hidden by the usage of a uniform interface in the integration platform (Process Integration).
Collaborate between distributed and scattered applications and engineers over the network.
Interoperability between different operating systems and programming languages by the use of similar interfaces.
Take security considerations into account so that, for example, data is shared only with the right resources.
Visual guidance by interactive user interfaces and a common facade for all integrated applications.
Common components of integration platform
An integration platform typically contains a set of functional components, such as:
Message bus for enabling reliable messaging between enterprise applications.
Adapters to transform messages from and to application's proprietary protocol. Adapters often offer connectivity via common standards, like FTP, SFTP or format support, like EDI.
Transformation engine and visualized data mapping to transform messages or files from one format to another.
Metadata repository for storing information separated from processes, like business party.
Process Orchestration Engine for orchestration design and execution. In this context orchestration is a technical workflow that represents a business process or part of it.
Technical dashboard for tracking messages in a message bus and viewing execution history of orchestrations.
Scheduler for scheduling orchestrations
Batch engine for controlling large file transfers, batch jobs, execution of external scripts and other non-messaging based tasks.
Differentiation
An integration platform has a focus to be designed by and helpful to engineers. It has no intention to map business processes or integrate tools for supply chain management. Therefore, it is not related to those systems.
Interoperability | Integration platform | Engineering | 467 |
40,571,792 | https://en.wikipedia.org/wiki/Z%20Centauri | The Bayer designations z Centauri and Z Centauri are distinct. Due to technical limitations, both designations link here. For the star
Z Centauri, see SN 1895B
z Centauri, see HD 119921
See also
ζ Centauri
Centaurus | Z Centauri | Astronomy | 58 |
33,072,764 | https://en.wikipedia.org/wiki/National%20Ganga%20River%20Basin%20Authority | National Ganga River Basin Authority (NGRBA) is a financing, planning, implementing, monitoring and coordinating authority for the Ganges River, functioning under the Ministry of Jal Shakti, of India. The mission of the organisation is to safeguard the drainage basin which feeds water into the Ganges by protecting it from pollution or overuse. In July 2014, the NGRBA was transferred from the Ministry of Environment and Forests to the Department of Water Resources, River Development & Ganga Rejuvenation, formerly the Ministry of Water Resources (India).
The Government of India, in a notification issued on 20 September 2016, announced that it has taken the decision under the River Ganga (Rejuvenation, Protection and Management) Authorities Order 2016 to establish a new body named the "National Council for River Ganga (Rejuvenation, Protection and Management)" (NCRG) to replace the existing NGRBA. The new body will act as an authority replacing the existing National Ganga River Basin Authority for overall responsibility pollution prevention and rejuvenation of the Ganges Basin
Establishment
It was established by the Government of India, on 20 February 2009 under Section 3(3) of the Environment Protection Act, 1986, which also declared the Ganges as the "National River" of India.
Overview
The Prime Minister is the chair of the Authority. Other members include the cabinet ministers of ministries that include the Ganges among their direct concerns and the chief ministers of states through which the Ganges River flows. The Chief Ministers as members are from the states through which Ganges flow viz. Uttarakhand, UP, Bihar, Jharkhand, West Bengal, among others.
The first meeting of the National Ganga River Basin Authority was held on 5 October 2009.
In the 2010 Union budget of India, the allocation for National Ganga River Basin Authority doubled to 500 crore (5,000,000,000.00).
Members of the NGRBA
There are total of 23 members of the NGRBA. 14 out of 23 come from the government sectors whereas the remaining 9 come from the NGO sector.
Government members of the Committee
Members belonging to the government sector are as follows:
Prime Minister of India, chair
Minister of Environment and Forests (Union Minister)
Minister of Finance
Minister of Urban Development
Minister of Water Resources
Minister of Power
Minister of Sciences and Technology
Chief Minister of Uttarakhand
Chief Minister of Uttar Pradesh
Chief Minister of Bihar
Chief Minister of Jharkhand
Chief Minister of West Bengal
Ministry of Environment and Forests (state minister)
Ministry of Environment and Forests, secretary
Expert members of the committee
Members belonging to the NGO sector are as follows:
Justice(Retd.) Giridhar Malviya, Patron, Ganga Mahasabha, Varanasi.
Shri Mohan Singh Rawat Gaonwasi, Ex. Minister Uttarakhand.
Shri M.A. Chitle, Maharashtra.
Dr. Bhure lal, IAS (Retd.), Delhi
Shri N.Vittal, Chennai
References
External links
National Ganga River Basin Authority, website
2009 establishments in Delhi
Ganges
Government agencies of India
Government agencies established in 2009
Environment of India
Organisations based in Delhi
Ecological restoration
Water in India
Ministry of Water Resources (India)
Environmental organisations based in India | National Ganga River Basin Authority | Chemistry,Engineering | 649 |
39,383,078 | https://en.wikipedia.org/wiki/Interval%20propagation | In numerical mathematics, interval propagation or interval constraint propagation is the problem of contracting interval domains associated to variables of R without removing any value that is consistent with a set of constraints (i.e., equations or inequalities). It can be used to propagate uncertainties in the situation where errors are represented by intervals. Interval propagation considers an estimation problem as a constraint satisfaction problem.
Atomic contractors
A contractor associated to an equation involving the variables x1,...,xn is an operator which contracts the intervals [x1],..., [xn] (that are supposed to enclose the xi's) without removing any value for the variables that is consistent with the equation.
A contractor is said to be atomic if it is not built as a composition of other contractors. The main theory that is used to build atomic contractors are based on interval analysis.
Example. Consider for instance the equation
which involves the three variables x1,x2 and x3.
The associated contractor is given by the following statements
For instance, if
the contractor performs the following calculus
For other constraints, a specific algorithm for implementing the atomic contractor should be written. An illustration is the atomic contractor associated to the equation
is provided by Figures 1 and 2.
Decomposition
For more complex constraints, a decomposition into atomic constraints (i.e., constraints for which an atomic contractor exists) should be performed. Consider for instance the constraint
could be decomposed into
The interval domains that should be associated to the new intermediate variables are
Propagation
The principle of the interval propagation is to call all available atomic contractors until no more contraction could be observed.
As a result of the Knaster-Tarski theorem, the procedure always converges to intervals which enclose all feasible values for the variables. A formalization of the interval propagation can be made thanks to the contractor algebra. Interval propagation converges quickly to the result and can deal with problems involving several hundred of variables.
Example
Consider the electronic circuit of Figure 3.
Assume that from different measurements, we know that
From the circuit, we have the following equations
After performing the interval propagation, we get
References
Algebra of random variables
Numerical analysis
Statistical approximations | Interval propagation | Mathematics | 443 |
37,008,975 | https://en.wikipedia.org/wiki/IBM%201009 | The IBM 1009 Data Transmission Unit was an IBM communications controller introduced in 1960. The 1009 used the Synchronous transmit-receive (STR) protocol to transfer data at 150 characters per second (cps) over a single point-to-point dial or leased telephone line. The system was advertised as being able to "link the magnetic core memories of IBM 1401 computers over telephone lines."
The 1009 attached to IBM 1400 series computers such as the 1401
In 1961 the transmission rate was doubled to 300 cps.
In 1962 the 1009 was part of a test of data communications using the Telstar satellite to link two 1401 computer systems.
References
External links
Photo of a 1009 at the Computer History Museum
1009
IBM transistorized computers
Computer-related introductions in 1960
Link protocols
Communications satellites
1962 in spaceflight | IBM 1009 | Technology | 171 |
1,051,404 | https://en.wikipedia.org/wiki/Monounsaturated%20fat | In biochemistry and nutrition, a monounsaturated fat is a fat that contains a monounsaturated fatty acid (MUFA), a subclass of fatty acid characterized by having a double bond in the fatty acid chain with all of the remaining carbon atoms being single-bonded. By contrast, polyunsaturated fatty acids (PUFAs) have more than one double bond.
Molecular description
Monounsaturated fats are triglycerides containing one unsaturated fatty acid. Almost invariably that fatty acid is oleic acid (18:1 n−9). Palmitoleic acid (16:1 n−7) and cis-vaccenic acid (18:1 n−7) occur in small amounts in fats.
Health
Studies have shown that substituting dietary monounsaturated fat for saturated fat is associated with increased daily physical activity and resting energy expenditure. More physical activity was associated with a higher-oleic acid diet than one of a palmitic acid diet. From the study, it is shown that more monounsaturated fats lead to less anger and irritability.
Foods containing monounsaturated fats may affect low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol.
Levels of oleic acid along with other monounsaturated fatty acids in red blood cell membranes were positively associated with breast cancer risk. The saturation index (SI) of the same membranes was inversely associated with breast cancer risk. Monounsaturated fats and low SI in erythrocyte membranes are predictors of postmenopausal breast cancer. Both of these variables depend on the activity of the enzyme delta-9 desaturase (Δ9-d).
In children, consumption of monounsaturated oils is associated with healthier serum lipid profiles.
The Mediterranean diet is one heavily influenced by monounsaturated fats. In the late 20th century, people in Mediterranean countries consumed more total fat than Northern European countries, but most of the fat was in the form of monounsaturated fatty acids from olive oil and omega-3 fatty acids from fish, vegetables, and certain meats like lamb, while consumption of saturated fat was minimal in comparison.
A 2017 review found evidence that the practice of a Mediterranean diet could lead to a decreased risk of cardiovascular diseases, overall cancer incidence, neurodegenerative diseases, diabetes, and early death. A 2018 review showed that the practice of the Mediterranean diet may improve overall health status, such as the reduced risk of non-communicable diseases. It also may reduce the social and economic costs of diet-related illnesses.
Diabetes
Increasing monounsaturated fat and decreasing saturated fat intake could improve insulin sensitivity, but only when the overall fat intake of the diet was low. However, some monounsaturated fatty acids (in the same way as saturated fats) may promote insulin resistance, whereas polyunsaturated fatty acids may be protective against insulin resistance.
Sources
Monounsaturated fats are found in animal flesh such as red meat, whole milk products, nuts, and high fat fruits such as olives and avocados. Algal oil is about 92% monounsaturated fat. Olive oil is about 75% monounsaturated fat. The high oleic variety sunflower oil contains at least 70% monounsaturated fat. Canola oil and cashews are both about 58% monounsaturated fat. Tallow (beef fat) is about 50% monounsaturated fat. and lard is about 40% monounsaturated fat. Other sources include hazelnut, avocado oil, macadamia nut oil, grapeseed oil, groundnut oil (peanut oil), sesame oil, corn oil, popcorn, whole grain wheat, cereal, oatmeal, almond oil, sunflower oil, hemp oil, and tea-oil Camellia.
See also
High density lipoprotein
Fatty acid synthesis
References
External links
Fats (Mayo Clinic)
The Chemistry of Unsaturated Fats
Food science
Lipids
Nutrition
de:Fettsäuren#Gesättigte und ungesättigte Fettsäuren | Monounsaturated fat | Chemistry | 896 |
4,086,824 | https://en.wikipedia.org/wiki/Selective%20soldering | Selective soldering is the process of selectively soldering components to printed circuit boards and molded modules that could be damaged by the heat of a reflow oven or wave soldering in a traditional surface-mount technology (SMT) or through-hole technology assembly processes. This usually follows an SMT oven reflow process; parts to be selectively soldered are usually surrounded by parts that have been previously soldered in a surface-mount reflow process, and the selective-solder process must be sufficiently precise to avoid damaging them.
Processes
Assembly processes used in selective soldering include:
Selective aperture tooling over wave solder: These tools mask off areas previously soldered in the SMT reflow soldering process, exposing only those areas to be selectively soldered in the tool's aperture or window. The tool and printed circuit board (PCB) assembly are then passed over wave soldering equipment to complete the process. Each tool is specific to a PCB assembly.
Mass selective dip solder fountain: A variant of selective-aperture soldering in which specialized tooling (with apertures to allow solder to be pumped through it) represent the areas to be soldered. The PCB is then presented over the selective-solder fountain; all selective soldering of the PCB is soldered simultaneously as the board is lowered into the solder fountain. Each tool is specific to a PCB assembly.
Miniature wave selective solder : This typically uses a round miniature pumped solder wave, similar to the end of a pencil or crayon, to sequentially solder the PCB. The process is slower than the two previous methods, but more accurate. The PCB may be fixed, and the wave solder pot moved underneath the PCB; alternately, the PCB may be articulated over a fixed wave or solder bath to undergo the selective-soldering process. Unlike the first two examples, this process is toolless.
Laser Selective Soldering System: A new system, able to import CAD-based board layouts and use that data to position a laser to directly solder any point on the board. Its advantages are the elimination of thermal stress, its non-contact quality, consistent high-quality solder joints and flexibility. Soldering time averages one second per joint; stencils and solder masks may be eliminated from the circuit board to reduce manufacturing costs.
Less-common selective soldering processes include:
Hot-iron solder with wire-solder feed
Induction solder with paste-solder, solder-laden pads or preforms and hot gas (including hydrogen), with a number of methods of presenting the solder
Other selective soldering applications are non-electronic, such as lead-frame attachment to ceramic substrates, coil-lead attachment, SMT attachment (such as LEDs to PCBs) and fire sprinklers (where the fuse is low-temperature solder alloys).
Regardless of the selective soldering equipment used, there are two types of selective flux applicators: spray and dropjet fluxers. The spray fluxer applies atomized flux to a specific area, while the dropjet fluxer is more precise; the choice depends on the circumstances surrounding the soldering application.
Miniature wave selective solder fountain
The miniature wave selective solder fountain type is widely used, yielding good results if the PCB design and manufacturing process are optimized. Key requirements for selective fountain type soldering are:
Process
Nozzle diameter selection according to solder-joint geometry, nearby component clearance, component lead height and wettable or non-wettable nozzle
Solder temperature: Set value or actual value on plated through-hole part
Contact time
Preheating
Flux type: No-clean, organic-based; method of fluxing (spray or dropjet)
Soldering: Drag, dip or angle method
Design
Temperature requirement (for soldered part) and component selection
Nearby SMD through-hole component clearance
Ratio of component pin diameter to plated through-hole
Component lead length
Thermal decoupling
Solder masking (green masking) distance from component pad
Drop-Jet
The Drop-Jet is an Electromechanical device which is capable of depositing a droplet of flux on demand onto a surface such as a Printed Circuit Board and or component pin.
Thermal profiling
The thermal profile of the selective process is critical as with other common automated soldering techniques.
Topside temperature measurements within the pre-heat stage must be verified as with conventional flow solder machine, additionally flux activation must be verified as sufficient.
As number of miniature profiling dataloggers are now available to make the process more simple such as the Solderstar Pro units.
Selective solder optimization
A number of fixtures are available to allow daily checking of the selective solder process, these instruments allow the verification of machine parameters to be performed on a periodic basis.
Parameters such as contact time, X/Y speeds, nozzle wave height and profile temperature can all be measured.
Use of nitrogen atmosphere
Selective soldering is normally undertaken in a nitrogen atmosphere. This prevents oxidation of the fountain surface and results in better wetting. Less flux is needed with less left-over residue. The use of nitrogen results in clean, shiny joints without the need for PCB cleaning or brushing.
References
Printed circuit board manufacturing
Soldering | Selective soldering | Engineering | 1,082 |
19,036,648 | https://en.wikipedia.org/wiki/Paolo%20Virno | Paolo Virno (; ; born 14 May 1952) is an Italian philosopher, semiologist and a figurehead for the Italian Marxist movement. Implicated in belonging to illegal social movements during the 1960s and 1970s, Virno was arrested and jailed in 1979, accused of belonging to the Red Brigades. He spent several years in prison before finally being acquitted, after which he organized the publication Luogo Comune (Italian for "commonplace") in order to vocalize the political ideas he developed during his imprisonment. Virno currently teaches philosophy at the University of Rome.
Biography
Virno was born in Naples, but spent his childhood and adolescence in Genoa. He had his first political experiences when joining the social movements of 1968—the association between personal fulfillment and anti-capitalism, typical of the critique artiste of the 1960s, which then constituted one of the key reasons for his political philosophy. He moved to Rome with his family at the beginning of the 1970s, where he studied philosophy in university.
Simultaneously, Virno was involved in the labour movement and campaigned in the organization Potere Operaio, a Marxist group involved in the recruitment and mobilization of industrial workers. Potere Operaio, unlike political communists of the Soviet Union and China who sought to combine the student bodies with the workers' unions, focused mainly on factory and industrial workers in a program stemming from Marx's theory criticising the organization of work. Virno participated in the movement, organizing protests and strikes in northern Italian factories, until its dissolution in 1973.
In 1977 Virno presented his doctoral thesis on the concept of work and the theory of consciousness of Theodor Adorno, while actively participating in the movement of 1977, which organized around the precariousness of workers. The Metropolitan magazine, which he founded along with Oreste Scalzone and Franco Piperno, was revered as the body of the intellectual movement at the time. Two years later, the editorial board of Metropolitan France was jailed on charges of belonging to the Red Brigades.
The three-year period of custody was a time of intense intellectual activity for Virno and others involved. After being sentenced in 1982 to 12 years in prison for "subversive activities and creation of an armed group" (though the charges of belonging to the Red Brigades did not materialise), Virno appealed and was released pending trial in the second instance; in 1987 he would eventually be acquitted, along with Piperno. His experience during these years were fed into the organization of the Luogo Comune publication, devoted to the analysis of life forms within postfordism.
In 1993 Virno left his post as editor of Luogo Comune to teach philosophy at the University of Urbino. In 1996 he was invited to talk at the University of Montreal and upon his return he held the chair of philosophy of language, semiotics and ethics of communication at the University of Cosenza (Calabria). He now teaches at the University of Rome.
Philosophical work
The early works of Virno were directly linked to his political participation, but after years of imprisonment, which along with his fellow prisoners, he conducted intensive studies of philosophy, and his focus on theoretical research has become more ambitious, covering political philosophy, linguistics and the study of mass media.
On the one hand, studies pertaining to philosophy of language have led to the confrontation of the classic themes of philosophy — like the analysis of subjectivity — with the limits imposed under linguistics. On the other hand, Virno has explored the ethical dimension of communication. The juncture of these fields was found to be a materialism that encompasses the processes of language and thought as a working link, keeping in line with the traditions of Theodor Adorno and Alfred Sohn-Rethel, the interrelationship between work, thought, language, society and history is the nexus of its philosophical thought.
The philosophical concepts, however, maintained a close link with theory and action-related policies; notions of "world", "power", "potential" or "history", which have been the focus of many of his works, were in fact conceived in key by Marx. Virno, along with many of his contemporaries such as Antonio Negri, has abandoned and argued against the hegemony of the dialectic tradition in Marxist philosophy.
Virno maintains the status of historical and linguistic concepts as being political-state, sovereignty, obedience, legality, legitimacy, which are accepted in social theory and philosophy as invariant, although polemically are considered to have been invented in the 17th century, with very specific and controversial political objectives. The reinvention of the concepts of society is part of the political task that has been proposed, regarding the concept of exodus — perhaps the best example of this joint, where the personal experiences of emotion are understood as an act of resistance toward established power and status quo. The assumption by the personality of the flight as a reaction to the social structure. On these lines, Virno has criticized these restrictions as symbolic of the counter-culture movements.
Bibliography
Italian:
Convenzione e Materialismo (1986); Roma: Ed. Theoria
Opportunisme, Cynisme et Peur. Ambivalence du Désenchantement Suivi de les Labyrinthes de la Langue (1991); Paris-Combas: Editions de l'éclat
Mondanità. L'idea di "Mondo" tra Esperienza Sensibile e Sfera Pubblica (1994); Roma: Ed. Manifestolibri
Parole con parole. Poteri e Limiti del Linguaggio (1995); Roma: Donzelli
Publications in English:
A Grammar of the Multitude. New York: Semiotext(e), 2004. ISBN 9781584350217
Multitude: Between Innovation and Negation. New York: Semiotext(e), 2008. ISBN 1584350504
When the Word Becomes Flesh. New York: Semiotext(e), 2015. ISBN 1584350946
Déjà Vu and the End of History. New York: Verso Books, 2015. ISBN 1781686114
Essay on Negation: For a Linguistic Anthropology. London/Calcutta: Seagull Books, 2018. ISBN 0857424386
Convention and Materialism: Uniqueness without Aura. Translated by Lorenzo Chiesa. Cambridge, Mass.: MIT Press, 2021. ISBN 026204580X
The Idea of World: Public Intellect and Use of Life. London/Calcutta: Seagull Books, 2022. ISBN 0857429892
See also
Autonomy
Mario Tronti
Antonio Negri
Franco Berardi
Mariarosa Dalla Costa
Autonomist Marxism
Counterculture
References
External links
In Castilian
"Virtuosismo y revolución: notas sobre el concepto de acción política"
"Virtuosismo y revolución, la acción política en la época del desencanto" (PDF)
"Gramática de la multitud: Para un análisis de las formas de vida contemporáneas" (PDF)
"La felicidad sigue siendo el asunto principal"
"Ante un nuevo siglo XVII"
"Dossier de lecturas seminario Paolo Virno" (PDF)
Iniciando un foro sobre "Gramática...", etc.
"Cuando el verbo se hace carne: Lenguaje y naturaleza humana", texto de Virno
"Cuando el verbo se hace carne: Lenguaje y naturaleza humana"
"Cuando el Verbo se Hace Carne" - P. Virno (zip)
"El chiste y la acción innovadora"
Other languages
"Grammatica della moltitudine:Per un’analisi delle forme di vita contemporanee"
"Grammaire de la multitude: Pour une analyse des formes de vie contemporaines"
"A Grammar of the Multitude: For an Analysis of Contemporary Forms of Life"
Déjà Vu and the End of History
Autonomism
1952 births
Living people
20th-century Italian philosophers
21st-century Italian philosophers
Italian communists
Italian political philosophers
Italian sociologists
Marxist theorists
Materialists
Social philosophers
Academic staff of Roma Tre University
Marxian critique of political economy | Paolo Virno | Physics | 1,713 |
25,313,078 | https://en.wikipedia.org/wiki/Certified%20broadcast%20technologist | Certified Broadcast Technologist (CBT) is a title granted to an individual that successfully meets the experience or examination requirements of the certification. The certification is regulated by the Society of Broadcast Engineers (SBE). The CBT title is protected by copyright laws. Individuals who use the title without consent from the Society of Broadcast Engineers could face legal action.
The SBE certifications were created to recognize individuals who practice in career fields which are not regulated by state licensing or Professional Engineering programs. Marine Radio and radar systems still require a Federal Communications Commission (FCC) license apart from an SBE certification. Broadcast Engineering is regulated at the national level and not by individual states.
See also
List of post-nominal letters
External links
Certified Broadcast Technologist (CBT) Requirements & Application
SBE official website
Broadcast engineering
Professional titles and certifications | Certified broadcast technologist | Engineering | 167 |
18,369,112 | https://en.wikipedia.org/wiki/KCNS1 | Potassium voltage-gated channel subfamily S member 1 is a protein that in humans is encoded by the KCNS1 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
References
Further reading
External links
Ion channels | KCNS1 | Chemistry | 50 |
251,366 | https://en.wikipedia.org/wiki/Hypotenuse | In geometry, a hypotenuse is the side of a right triangle opposite the right angle. It is the longest side of any such triangle; the two other shorter sides of such a triangle are called catheti or legs. The length of the hypotenuse can be found using the Pythagorean theorem, which states that the square of the length of the hypotenuse equals the sum of the squares of the lengths of the two legs. Mathematically, this can be written as , where a is the length of one leg, b is the length of another leg, and c is the length of the hypotenuse.
For example, if one of the legs of a right angle has a length of 3 and the other has a length of 4, then their squares add up to 25 = 9 + 16 = 3 × 3 + 4 × 4. Since 25 is the square of the hypotenuse, the length of the hypotenuse is the square root of 25, that is, 5. In other words, if and , then .
Etymology
The word hypotenuse is derived from Greek (sc. or ), meaning "[side] subtending the right angle" (Apollodorus), hupoteinousa being the feminine present active participle of the verb hupo-teinō "to stretch below, to subtend", from teinō "to stretch, extend". The nominalised participle, , was used for the hypotenuse of a triangle in the 4th century BCE (attested in Plato, Timaeus 54d). The Greek term was loaned into Late Latin, as hypotēnūsa. The spelling in -e, as hypotenuse, is French in origin (Estienne de La Roche 1520).
Properties and calculations
In a right triangle, the hypotenuse is the side that is opposite the right angle, while the other two sides are called the catheti or legs. The length of the hypotenuse can be calculated using the square root function implied by the Pythagorean theorem. It states that the sum of the two legs squared equals the hypotenuse squared. In mathematical notation, with the respective legs labelled a and b, and the hypotenuse labelled c, it is written as . Using the square root function on both sides of the equation, it follows that
As a consequence of the Pythagorean theorem, the hypotenuse is the longest side of any right triangle; that is, the hypotenuse is longer than either of the triangle's legs. For example, given the length of the legs a = 5 and b = 12, then the sum of the legs squared is (5 × 5) + (12 × 12) = 169, the square of the hypotenuse. The length of the hypotenuse is thus the square root of 169, denoted , which equals 13.
The Pythagorean theorem, and hence this length, can also be derived from the law of cosines in trigonometry. In a right triangle, the cosine of an angle is the ratio of the leg adjacent of the angle and the hypotenuse. For a right angle γ (gamma), where the adjacent leg equals 0, the cosine of γ also equals 0. The law of cosines formulates that holds for some angle θ (theta). By observing that the angle opposite the hypotenuse is right and noting that its cosine is 0, so in this case θ = γ = 90°:
Many computer languages support the ISO C standard function hypot(x,y), which returns the value above. The function is designed not to fail where the straightforward calculation might overflow or underflow and can be slightly more accurate and sometimes significantly slower.
Some languages have extended the definition to higher dimensions. For example, C++17 supports ; this gives the length of the diagonal of a rectangular cuboid with edges x, y, and z. Python 3.8 extended to handle an arbitrary number of arguments.
Some scientific calculators provide a function to convert from rectangular coordinates to polar coordinates. This gives both the length of the hypotenuse and the angle the hypotenuse makes with the base line (c1 above) at the same time when given x and y. The angle returned is normally given by atan2(y,x).
Trigonometric ratios
By means of trigonometric ratios, one can obtain the value of two acute angles, and , of the right triangle.
Given the length of the hypotenuse and of a cathetus , the ratio is:
The trigonometric inverse function is:
in which is the angle opposite the cathetus .
The adjacent angle of the catheti is = 90° –
One may also obtain the value of the angle by the equation:
in which is the other cathetus.
See also
Cathetus
Triangle
Space diagonal
Nonhypotenuse number
Taxicab geometry
Trigonometry
Special right triangles
Pythagoras
Norm_(mathematics)#Euclidean_norm
Notes
References
Hypotenuse at Encyclopaedia of Mathematics
Parts of a triangle
Trigonometry
Pythagorean theorem | Hypotenuse | Mathematics | 1,123 |
32,588,202 | https://en.wikipedia.org/wiki/Diborane%284%29 | Diborane(4) is a transient inorganic compound with the chemical formula . Stable derivatives are known.
Diborane(4) has been produced by abstraction of two hydrogen atoms from diborane(6) using atomic fluorine and detected by photoionization mass spectrometry. Computational studies predict a structure in which are two hydrogen atoms bridging the two boron atoms via three-centre two-electron bonds in addition to the 2-centre, 2-electron bond between the two boron atoms and one terminal hydrogen atom bonded to each boron atom.
Several stable derivatives of diborane(4) have been reported.
References
Boranes | Diborane(4) | Chemistry | 137 |
49,528,276 | https://en.wikipedia.org/wiki/Behavioral%20plasticity | Behavioral plasticity is the change in an organism's behavior that results from exposure to stimuli, such as changing environmental conditions. Behavior can change more rapidly in response to changes in internal or external stimuli than is the case for most morphological traits and many physiological traits. As a result, when organisms are confronted by new conditions, behavioral changes often occur in advance of physiological or morphological changes. For instance, larval amphibians changed their antipredator behavior within an hour after a change in cues from predators, but morphological changes in body and tail shape in response to the same cues required a week to complete.
Background
For many years, ethologists have studied the ways that behavior can change in response to changes in external stimuli or changes in the internal state of an organism. In a parallel literature, psychologists studying learning and cognition have spent years documenting the many ways that experiences in the past can affect the behavior an individual expresses at the current time. Interest in behavioral plasticity gained prominence more recently as an example of a type of phenotypic plasticity with major consequences for evolutionary biology.
Types
Behavioral plasticity can be broadly organized into two types: exogenous and endogenous. Exogenous plasticity refers to the changes in behavioral phenotype (i.e., observable behaviors) caused by an external stimulus, experience, or environment. Endogenous plasticity encompasses plastic responses that result from changes in internal cues, such as genotype, circadian rhythms, and menstruation.
These two broad categories can be further broken down into two other important classifications. When an external stimulus elicits or "activates" an immediate response (an immediate effect on behavior), then the organism is demonstrating contextual plasticity. This form of plasticity highlights the concept that external stimuli in a given context activate neural and hormonal mechanisms or pathways which already exist inside the organism. In contrast, if an organism's current behavior is altered by past experiences, then the animal is said to be exhibiting developmental or "innate" behavioral plasticity. This form of plasticity is generally thought to require new neuronal pathways to form.
Developmental behavioral plasticity corresponds to the commonly used definition of plasticity: a single genotype can express more than one behavioral phenotype as a result of different developmental routes triggered by differences in past experiences. Developmental plasticity thus includes what is referred to as "learning". However, developmental plasticity also includes developmental changes in morphology and physiology relevant to a particular behavior, such as changes in muscles, limbs, or bones that influence foraging or locomotion throughout and organism's life.
A major difference between developmental and contextual plasticity is the inherent trade-off between the time of interpreting a stimulus and exhibiting a behavior. Contextual plasticity is a near immediate response to the environment. The underlying hormonal networks/neuronal pathways are already present, so it is only a matter of activating them. In contrast, developmental plasticity requires internal changes in hormonal networks and neuronal pathways. As a result, developmental plasticity is often, although not always, a slower process than contextual plasticity. For instance, habituation is a type of learning (developmental plasticity) that can occur within a short period of time. One of the advantages of developmental behavioral plasticity that occurs over extended periods of time is that such changes can occur in concert with changes in morphological and physiological traits. In such cases, the same set of external or internal stimuli can lead to coordinated changes in suites of behavioral, morphological and physiological traits.
Examples
Contextual plasticity is typically studied by presenting the same individual with different external stimuli, and then recording their responses to each stimulus. For instance, ants can rapidly alter their running speed in response to changes in the external temperature. Another example of contextual plasticity occurs when birds change their vocalizations in response to changes in the pitch or intensity of background noise. Contextual plasticity plays a major role in studies of mate preference, in which each subject is exposed to cues from different mates, and its response to each cue is quantified. In this case, a stronger attractive response to a particular cue is assumed to reflect a preference for mates with that cue.
Developmental plasticity encompasses the many ways that experiences in an organism's past can affect its current behavior. Developmental plasticity thus includes learning, acclimation, and any situation in which environmental conditions early in life affects the behavior expressed later in life (also called ontogenetic plasticity. Since a given individual can only be raised under one set of conditions, ontogenetic plasticity is studied by dividing matched individuals into two or more groups, and then rearing each group under a different set of conditions. For instance, this experimental design was used to demonstrate that the density at which moth larvae were raised affected the courtship signals that they produced as adults.
Endogenous plasticity includes circadian rhythms, circannual rhythms, and age-dependent changes in behavior. A good example of endogenous plasticity occurs with zebrafish (Danio rerio). Larval zebrafish exhibit circadian rhythms in their responsiveness to light. Even when they are maintained under continuous darkness, the fish are much more responsive to changes in light (i.e. higher contextual plasticity) during subjective day than during subjective night. Another example involves the changes in an individual's behavior and hormonal profile around the time of sexual maturity; such changes are affected changes in physiology that occurred months to years earlier in life.
Potential vs. realized plasticity
A useful distinction to make when looking at behavioral plasticity is between potential and realized plasticity. Potential plasticity refers to the ability of a given phenotypic trait to vary in its response to variation in stimuli, experiences, or environmental conditions. Thus, potential plasticity is the theoretical range in behavioral plasticity that could be expressed. This value is never truly known, but serves more as a baseline in plasticity models. Realized plasticity, on the other hand, refers to the extent to which a given phenotype actually varies in response to changes in a specific stimulus, experience, or environmental condition.
Individual differences in behavioral plasticity
Recent studies of animals have documented individual differences in virtually all of the different types of behavioral plasticities described above. In addition, behavioral plasticities may themselves be developmentally plastic: individual differences in a type of plasticity that is expressed at a given age may be affected by the conditions to which the subjects were exposed earlier in life. In a variety of species, for instance, social cues during the juvenile period affect the contextual plasticity of responses to cues from potential mates at adulthood. As is the case for many other types of plasticity, researchers studying the development of individual differences in behavioral plasticity have found that genes, prior experiences and interactions between these factors contribute to the individual differences in behavioral plasticity that are expressed at a given age or lifestage. Another question that is currently attracting interest from students of both animal and human behavior is whether different types of behavioral plasticities are correlated with one another across individuals: i.e., whether some individuals are generally more plastic than others. Although there is some evidence that certain types of cognitive traits tend to be positively correlated with one another across individuals (see the g factor in humans), at present there is scant evidence that other types of plasticity (e.g. contextual plasticity and ontogenetic plasticity) are correlated with one another across individuals or genotypes in humans or animals.
Evolutionary causes and consequences
Behavioral plasticity can have major impacts on the evolutionary fitness of an individual. Both developmental and contextual plasticity influence the fitness of an animal in a novel environment by increasing the probability that the animal will survive in that environment. Developmental plasticity is particularly important in terms of survival in novel environments, because trial-and-error processes such as learning (which encompass both phenotype sampling and environmental feedback) have the ability to immediately shift an entire population close to a new adaptive norm. As such, the ability to express some level of behavioral plasticity can be very advantageous. In fluctuating environments, animals that can change how they respond to differences in stimuli would have a leg up over animals that were set in a rigid phenotype. However, this would only be the case if the costs of maintaining the ability to change phenotype was lower than the benefit conferred to the individual.
References
Behavioral ecology
Evolutionary biology
Behavior modification
Behavioral neuroscience | Behavioral plasticity | Biology | 1,730 |
75,331,989 | https://en.wikipedia.org/wiki/Timon%20McPhearson | Timon McPhearson is an American urban ecologist, researcher, academic and author. He is Professor of Urban Ecology at The New School and the founder and director of its Urban Systems Lab. McPhearson is known for his interdisciplinary research on the interacting social-ecological-technological processes that drive urban system dynamics and impact human well-being. He is a research fellow at the Cary Institute of Ecosystem Studies and Stockholm Resilience Centre. McPhearson received the 2023 Sustainability Science Award from the Ecological Society of America.
Academic background
McPhearson received a B.S. in Environmental Biology from Taylor University 1997, and then a PhD in ecology, Evolution, and Natural Resources from Rutgers University in 2004. In 2008, he finished his Postdoctoral research in Ecology, Evolution, and Environmental Biology (E3B) from the Earth Institute at Columbia University.
Career
From 2003 to 2005, McPhearson worked as a biodiversity scientist for the Center for Biodiversity and Conservation at the American Museum of Natural History (AMNH). And from 2004 to 2009, he worked as a scientist for the Network of Conservation Educators and Practitioners at the AMNH, including as a scientific advisor at Science Bulletins, an original production of the National Center for Science Literacy, Education, and Technology (NCSLET), which is also a part of the Department of Education at AMNH.
In 2016, McPhearson co-founded the Future Earth Urban Knowledge Network, an international network of multidisciplinary researchers and innovators working on resolving cumbersome urban problems worldwide and served as co-chair until 2021.
From 2019 to 2021, McPhearson consulted for UN-HABITAT, CGIAR's Research Program on Climate Change, Agriculture and Food Security, the Green Climate Fund (GCF) and the International Fund for Agricultural Development (IFAD).
During the COVID-19 pandemic, and from 2020 to 2022, McPhearson was a member at the NYC Mayor's Office of Resiliency Rapid Research and Assessment Initiative on COVID-19 and a partner at NYC Mayor's Office of Data Analytics and the mayor's Office of Policy and Planning, COVID Recovery Data Partnership.
McPhearson has been an adviser at the World Resources Institute, Ross Center for Sustainable Cities since 2020, an inaugural member of the World Economic Forum (WEF)'s Global Commission on BiodiverCities since 2021, and member of The New School's Zolberg Institute's Cities and Human Mobility Research Collaborative since 2020 and Tishman Environment and Design Center at The New School since 2016.
McPhearson contributed to the Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES) first global assessment as a contributing author from 2018 to 2020, and a lead author for Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6).
Academia
From 2008 to 2009, McPhearson was a visiting assistant professor of ecology at Columbia University's Earth Institute.
From 2008 to 2016, McPhearson was an assistant professor of Urban Ecology at The New School. He was tenured at associate professor level in 2016 and appointed as full professor in 2021.
In 2015, McPhearson founded the Urban Systems Lab at The New School and has been serving as its director, and from 2015 to 2017, he served as a chair of the Environmental Studies Program at The New School.
In 2017, McPhearson was a visiting research fellow at Humboldt University. He has also been serving as a senior research fellow at both the Cary Institute of Ecosystem Studies and at Stockholm University's Stockholm Resilience Center since 2017.
In 2021, McPhearson became a faculty affiliate at the Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences.
Bibliography
Books
Urban Planet: Knowledge towards Sustainable Cities, Cambridge University Press (2018)
Resilient Urban Futures, Springer-Nature (2021)
Nature-Based Solutions for Cities, Edward Elgar Publishing (2023)
Select publications
Gómez-Baggethun, Erik, Åsa Gren, David N. Barton, Johannes Langemeyer, Timon McPhearson, Patrick O’farrell, Erik Andersson, Zoé Hamstead, and Peleg Kremer. "Urban ecosystem services." Urbanization, biodiversity and ecosystem services: Challenges and opportunities: A global assessment (2013): 175–251.
McPhearson, Timon, Steward TA Pickett, Nancy B. Grimm, Jari Niemelä, Marina Alberti, Thomas Elmqvist, Christiane Weber, Dagmar Haase, Jürgen Breuste, and Salman Qureshi. "Advancing urban ecology toward a science of cities." BioScience 66, no. 3 (2016): 198–212.
Bennett, Elena M., Martin Solan, Reinette Biggs, Timon McPhearson, Albert V. Norström, Per Olsson, Laura Pereira et al. "Bright spots: seeds of a good Anthropocene." Frontiers in Ecology and the Environment 14, no. 8 (2016): 441–448.
McPhearson, T., D. Iwaniec, X. Bai. “Positives visions for guiding transformations toward desirable urban futures.” Current Opinion in Environmental Sustainability
McPhearson, T., S. Parnell, D. Simon, O. Gaffney, T. Elmqvist, X. Bai, D. Roberts, A. Revi. 2016. “Scientists must have a say in the future of cities.” Nature, 538:165-166
Dodman, D., B. Hayward, M. Pelling, V. Castan Broto, W. Chow, E. Chu, R. Dawson, L. Khirfan, T. McPhearson, A. Prakash, Y. Zheng, and G. Ziervogel. (2022). IPCC AR6 WGII Chapter 6: Cities, Settlements and Key Infrastructure. In: Climate Change 2022: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, et al. (eds.)]. Cambridge University Press.
Ilieva, R.T., T. McPhearson. 2018. “Social media data for urban sustainability.” Nature Sustainability 1:553–565
Keeler, B.L., P. Hamel, T. McPhearson, et al. 2019. “Social-ecological and technological factors moderate the value of urban nature.” Nature Sustainability 2: 29-38
McPhearson, T., M. Raymond, C., Gulsrud, N., Albert, C., Coles, N., Fagerholm, N., Nagatsu, M., Olafsson, A.S., Soininen, N., and Vierikko, K. (2021). Radical changes for transformations to a good Anthropocene. npj Urban Sustainability. 1(5).
McPhearson, T., E. Cook, M. Berbés-Blázquez, C. Cheng, N.B. Grimm, et al. (2022). A social-ecological-technological systems approach to urban ecosystem services. One Earth, 5, 5, 505–518.
McPhearson, T., E. Andersson, T. Elmqvist, N.Frantzeskaki. 2015. “Resilience Of and Through Urban Ecosystem Services,“ Ecosystem Services 12:152-156,
Petchey, O.L., P.T. McPhearson, T.M. Casey, P.J. Morin. 1999. “Environmental warming alters food-web structure and ecosystem function.” Nature 420:69-72
Elmqvist, Thomas, Erik Andersson, Niki Frantzeskaki, Timon McPhearson, Per Olsson, Owen Gaffney, Kazuhiko Takeuchi, and Carl Folke. "Sustainability and resilience for transformation in the urban century." Nature sustainability 2, no. 4 (2019): 267–273.
Awards
2023 Sustainability Science Award, Ecological Society of America
2022 Gulbenkian Prize for Humanity (to IPCC and IPBES)
2021 BiodivERsA Prize, “Enabling Green and Blue Infrastructure Potential in Complex Social-Ecological Regions” (ENABLE Project)
2020 New York City Climate Heroes Award, NYC Department of Transportation and Human Impacts Institute
2019 Sustainability Science Award, Ecological Society of America
2019 Innovation in Sustainability Science Award, Ecological Society of America
2018 BiodivERsA Prize, “Urban Biodiversity and Ecosystem Services” (URBES Project)
2017 Distinguished University Teaching Award, The New School
References
Notes
External links
Urban Transformations Timon McPhearson
The New School's Urban Systems Lab
Timon McPhearson World Economic Forum
Ecologists
American ecologists
American academics
The New School faculty
Year of birth missing (living people)
Living people
Taylor University alumni
Rutgers University alumni | Timon McPhearson | Environmental_science | 1,877 |
47,531,801 | https://en.wikipedia.org/wiki/List%20of%20Navicula%20species | List of plankton species in the genus Navicula.
Species
, Algaebase lists 1280 accepted species and more than 1900 proposed species in the plankton genus Navicula. They include:
A
Navicula abbotti
Navicula abbottii
Navicula abbreviata
Navicula abdita
Navicula abducta
Navicula abelioensis
Navicula aberrans
Navicula abica
Navicula abiskoensis
Navicula aboensis
Navicula abonuensis
Navicula abraensis
Navicula abrupta
Navicula abscondita
Navicula abstrusa
Navicula abuensis
Navicula abunda
Navicula abundoides
Navicula acacia
Navicula accedens
Navicula accommoda
Navicula accurata
Navicula achthera
Navicula acephala
Navicula achnanthoides
Navicula achthera
Navicula acidobionta
Navicula acidobiontica
Navicula acidophila
Navicula acrosphaeria
Navicula actinota
Navicula acus
Navicula acuta
Navicula acuticuneata
Navicula acuticuneatula
Navicula acutirostris
Navicula acutissima
Navicula acutissima
Navicula adakensis
Navicula adakensis
Navicula adamantiformis
Navicula adamata
Navicula addae
Navicula admenda
Navicula adami
Navicula adampeensis
Navicula adamsii
Navicula addaae
Navicula addae
Navicula addicta
Navicula admenda
Navicula adminensis
Navicula adnatoides
Navicula adonis
Navicula adumbrata
Navicula advena
Navicula adversa
Navicula adversatrix
Navicula aedifex
Navicula aegyptiaca
Navicula aemula
Navicula aequalis
Navicula aequinoctialis
Navicula aequora
Navicula aequoria
Navicula aestimata
Navicula aestiva
Navicula affinis
Navicula affirmata
Navicula africana
Navicula agatkae
Navicula agma
Navicula agellus
Navicula aggerica
Navicula aggesta
Navicula aglaos
Navicula agnita
Navicula agma
Navicula agmastriata
Navicula agnewii
Navicula agnita
Navicula agrestiformis
Navicula agulhasica
Navicula ahmedabadensis
Navicula aikenenses
Navicula aikenensis
Navicula airdevronsixii
Navicula aitchelbee
Navicula ajajensis
Navicula aikensis
Navicula airdevronsixii
Navicula ajajensis
Navicula ajenaensis
Navicula aketechiensis
Navicula albanica
Navicula akimensis
Navicula aktinoides
Navicula alaskana
Navicula alea
Navicula aleemi
Navicula algor
Navicula aleemii
Navicula algeriensis
Navicula aleksandrae
Navicula algida
Navicula algor
Navicula alineae
Navicula alisoviana
Navicula altiplanensis
Navicula alineae
Navicula alisoviana
Navicula allista
Navicula allmaniana
Navicula allorgei
Navicula alpestris
Navicula alpha
Navicula alpina
Navicula alternans
Navicula alterofasciata
Navicula altiplanensis
Navicula amabilis
Navicula ambigua
Navicula americana
Navicula amerinda
Navicula amica
Navicula amicii
Navicula amicorum
Navicula ammophila
Navicula amnicola
Navicula amoena
Navicula amoena
Navicula amoenaeformis
Navicula amphibola
Navicula amphiceropsis
Navicula amphiceros
Navicula amphilepta
Navicula amphirhychus
Navicula amphirhynchus
Navicula amphirrhina
Navicula amphirhychus
Navicula amphisphenia
Navicula amphistylus
Navicula amphoroides
Navicula ampliata
Navicula amygdalina
Navicula anassae
Navicula anatis
Navicula anca
Navicula anceps
Navicula ancilla
Navicula ancilla
Navicula ancisa
Navicula ancora
Navicula anderabensis
Navicula anderssonii
Navicula andesitica
Navicula andicola
Navicula andium
Navicula andrussowii
Navicula anenuta
Navicula angelica
Navicula angelorum
Navicula angleana
Navicula anglica
Navicula anglophila
Navicula angolensis
Navicula angulati
Navicula angulosa
Navicula angarae
Navicula angelica
Navicula angulosa
Navicula angusta
Navicula anguste-fasciata
Navicula angustissima
Navicula anhuiensis
Navicula anna
Navicula ankobraensis
Navicula annexa
Navicula annulana
Navicula anopaia
Navicula antarctica
Navicula antarctica
Navicula antediluviana
Navicula antediluvianum
Navicula anthracis
Navicula antigua
Navicula antillarum
Navicula antiqua
Navicula antonii
Navicula antonioides
Navicula aparta
Navicula aperta
Navicula apia
Navicula apiculata
Navicula antediluvianum
Navicula antigua
Navicula antiqua
Navicula antonii
Navicula antonioides
Navicula antverpiensis
Navicula apiculata
Navicula apiculatoreinhardtii
Navicula applicita
Navicula applicitoides
Navicula approximatella
Navicula aquaedurae
Navicula applicitoides
Navicula approximata
Navicula apsteinii
Navicula apta
Navicula aquaeductae
Navicula aquitaniae
Navicula aquitaniae
Navicula aquosa
Navicula aradina
Navicula aranaria
Navicula arata
Navicula araucaniana
Navicula arcana
Navicula archeriana
Navicula archibaldiana
Navicula arcta
Navicula arctica
Navicula arctotenelloides
Navicula arcuata
Navicula ardis
Navicula ardua
Navicula arenaria
Navicula archeriana
Navicula arctotenelloides
Navicula applanata
Navicula applicita
Navicula appendiculata
Navicula arenariaeformis
Navicula arenicola
Navicula arenosa
Navicula arenaria
Navicula arenariaeformis
Navicula arenicola
Navicula arenula
Navicula argens
Navicula argunensis
Navicula argutiola
Navicula ariiensis
Navicula arkona
Navicula armata
Navicula armoricana
Navicula arenula
Navicula areschougiana
Navicula argens
Navicula arguens
Navicula argunensis
Navicula argutiola
Navicula arkona
Navicula armata
Navicula armoricana
Navicula arraniensis
Navicula artemidis
Navicula artificiosa
Navicula arvensiformis
Navicula arvensis
Navicula arverna
Navicula aspergilla
Navicula associata
Navicula asymbasia
Navicula arvensoides
Navicula arverna
Navicula asanwinsoensis
Navicula ashantiensis
Navicula asiatica
Navicula asklepieionensis
Navicula aspera
Navicula aspergilla
Navicula aspersa
Navicula asperula
Navicula associata
Navicula assula
Navicula assuloides
Navicula assymetrica
Navicula astrolabensis
Navicula asymbasia
Navicula asymetrica
Navicula asymmetrica
Navicula atacamana
Navicula atacamae
Navicula atasensis
Navicula athenae
Navicula atlantica
Navicula atwateri
Navicula arvensoides
Navicula arverna
Navicula asanwinsoensis
Navicula ashantiensis
Navicula asiatica
Navicula asklepieionensis
Navicula aspera
Navicula aspergilla
Navicula aspersa
Navicula asperula
Navicula associata
Navicula assula
Navicula assuloides
Navicula assymetrica
Navicula astrolabensis
Navicula asymbasia
Navicula asymetrica
Navicula asymmetrica
Navicula atacamae
Navicula atacamana
Navicula atalos
Navicula athenae
Navicula atlantica
Navicula atomarius
Navicula atomoides
Navicula atomus
Navicula atomus
Navicula atwateri
Navicula aubertii
Navicula aucklandica
Navicula aueri
Navicula aulacophaena
Navicula aurangabadensis
Navicula aurantiaca
Navicula aurora
Navicula australica
Navicula australomediocris
Navicula australoceanica
Navicula australoshetlandica
Navicula austrocollegarum
Navicula avenaceoides
Navicula avonensis
B
Navicula baardsethii
Navicula baccata
Navicula bacillaris
Navicula bacillifera
Navicula bacilliformis
Navicula bacillum
Navicula bacterium
Navicula bacula
Navicula bahiensis
Navicula bahuensoides
Navicula bahusiensis
Navicula baileyana
Navicula baileyi
Navicula bainii
Navicula balcanica
Navicula balnearis
Navicula bamboiensis
Navicula bannajensis
Navicula bansoensis
Navicula barbadense
Navicula barbadensis
Navicula barbara
Navicula barbarica
Navicula barberiana
Navicula barbitos
Navicula barclayana
Navicula barentsii
Navicula barkeriana
Navicula barklayana
Navicula barodensis
Navicula barrowiana
Navicula bartholomei
Navicula basaltaeproxima
Navicula basilica
Navicula basillica
Navicula bastianii
Navicula bastowii
Navicula bauemleri
Navicula bauemlerii
Navicula bawdiaensis
Navicula bayleana
Navicula bdesma
Navicula beaufortiana
Navicula beccariana
Navicula beckii
Navicula begeri
Navicula begerii
Navicula beketowii
Navicula bella
Navicula bellatii
Navicula belliatula
Navicula bellissima
Navicula belsesiensis
Navicula bendaensis
Navicula bengalensis
Navicula bergenensis
Navicula bergeni
Navicula bergerii
Navicula berriati
Navicula bertelsenii
Navicula bertrandi
Navicula besarensis
Navicula beta
Navicula beyrichiana
Navicula biaculeata
Navicula biakensis
Navicula bicapitata
Navicula bicapitellata
Navicula bicarinata
Navicula bicephala
Navicula bicephaloides
Navicula biceps
Navicula biclavata
Navicula biconica
Navicula biconifera
Navicula biconstricta
Navicula bicontracta
Navicula bicuneolus
Navicula bicuspidata
Navicula biddulphioides
Navicula bidentula
Navicula bievexa
Navicula bifax
Navicula bifissa
Navicula biflexa
Navicula bifurcatula
Navicula bigemmata
Navicula biglobosa
Navicula bilineata
Navicula bilobata
Navicula bimaculata
Navicula binaria
Navicula binodis
Navicula binodulosa
Navicula bintila
Navicula bioculata
Navicula bipectinalis
Navicula bipunctata
Navicula bipunctata
Navicula bipustulata
Navicula birhis
Navicula birostrata
Navicula birostris
Navicula biscalaris
Navicula biseriata
Navicula biskanterae
Navicula biskanteri
Navicula bistriata
Navicula bisulcata
Navicula bita
Navicula bituminosa
Navicula biwaensis
Navicula bjoernoeyaensis
Navicula blasii
Navicula bleischiana
Navicula bleischii
Navicula blessingii
Navicula blotii
Navicula bodosensis
Navicula boeckii
Navicula boergesenii
Navicula bogotensis
Navicula bolleana
Navicula bombiformis
Navicula bomboides
Navicula bombus
Navicula bongrainii
Navicula bonnieri
Navicula borbassii
Navicula borealis
Navicula borinquensis
Navicula borneoensis
Navicula borowkae
Navicula borrichii
Navicula borussica
Navicula boryana
Navicula boseana
Navicula bossvikensis
Navicula bosumtwiensis
Navicula botteriana
Navicula bottnica
Navicula boudetii
Navicula bouhardi
Navicula bourgi
Navicula bourrellyi
Navicula bourrellyivera
Navicula boyei
Navicula bozenae
Navicula branchiata
Navicula brasiliana
Navicula brasiliensis
Navicula braunii
Navicula brebissonii
Navicula breenii
Navicula brehmi
Navicula brehmii
Navicula brehmioides
Navicula breitenbuchii
Navicula brekkaensis
Navicula bremensis
Navicula bremeyeri
Navicula breviata
Navicula brevirostrata
Navicula brevis
Navicula brevissima
Navicula brockmanni
Navicula brockmannii
Navicula broetzii
Navicula bruchi
Navicula bruchii
Navicula brunelii
Navicula bruni
Navicula brunii
Navicula bruyanti
Navicula bryophila
Navicula bryophiloides
Navicula buccella
Navicula buchansiana
Navicula budayana
Navicula budda
Navicula budensis
Navicula buderiformis
Navicula bullata
Navicula bulnheimii
Navicula burcki
Navicula bushmanorum
Navicula butreensis
C
Navicula caddoensis
Navicula caenosus
Navicula calcuttensis
Navicula calcuttensis
Navicula caldwellii
Navicula calida
Navicula californica
Navicula caliginosa
Navicula calva
Navicula calvata
Navicula camerata
Navicula campanilae
Navicula campbellii
Navicula campylodiscus
Navicula canaliculata
Navicula canalis
Navicula canariana
Navicula cancelleta
Navicula candida
Navicula cantonatii
Navicula cantonensis
Navicula capensis
Navicula capillata
Navicula capitata
Navicula capitatoradiata
Navicula capitellata
Navicula capitoradiata
Navicula capitulata
Navicula capsa
Navicula capsula
Navicula caractacus
Navicula carassius
Navicula cardinaliculus
Navicula cardinalis
Navicula carecti
Navicula cari
Navicula caribaea
Navicula carinata
Navicula carinifera
Navicula cariocincta
Navicula carissima
Navicula carloffii
Navicula carminata
Navicula carolinensis
Navicula carpathorum
Navicula carstensenii
Navicula carteri
Navicula carvajaliana
Navicula casca
Navicula cascadensis
Navicula casertana
Navicula cassieana
Navicula castracanei
Navicula catalanogermanica
Navicula cataracta-rheni
Navicula cataractarum
Navicula catarinensis
Navicula caterva
Navicula catharinae
Navicula caupulus
Navicula cavernae
Navicula ceciliae
Navicula celinei
Navicula cellesensis
Navicula cendronii
Navicula centraster
Navicula centropunctata
Navicula cephalodes
Navicula ceratogramma
Navicula ceratostigma
Navicula ceres
Navicula cerneutia
Navicula cesatii
Navicula ceylanensis
Navicula chaberti
Navicula chadwickii
Navicula chandolensis
Navicula charlatii
Navicula charlottae
Navicula charontis
Navicula chasei
Navicula chasmaensis
Navicula chasmigera
Navicula chaspula
Navicula chassagnei
Navicula chauhanii
Navicula cherubim
Navicula chi
Navicula chiarae
Navicula chiengmaiensis
Navicula chilena
Navicula chilensis
Navicula chimmoana
Navicula chinensis
Navicula chingmaiensis
Navicula chloridorum
Navicula cholnokyana
Navicula cholnokyii
Navicula chordata
Navicula chrissiana
Navicula chutteri
Navicula chyzerii
Navicula ciliata
Navicula cimex
Navicula cincta
Navicula cinctaeformis
Navicula cingens
Navicula cingulatoides
Navicula cinna
Navicula circumnodosa
Navicula circumtexta
Navicula circumvallata
Navicula cistella
Navicula citrea
Navicula citriformis
Navicula clagesii
Navicula clamans
Navicula clarensiana
Navicula claromontensis
Navicula clathrata
Navicula clavata
Navicula claviana
Navicula claytoni
Navicula claytonii
Navicula clementis
Navicula clementoides
Navicula climacospheniae
Navicula cluthensis
Navicula cluthensoides
Navicula clypeus
Navicula coarctata
Navicula coccinella
Navicula cocconeiformis
Navicula cocconeoides
Navicula cocconioides
Navicula coccus
Navicula cochlearis
Navicula coei
Navicula coelata
Navicula coerulea
Navicula coffeiformis
Navicula colii
Navicula collersonii
Navicula collertsonii
Navicula collisiana
Navicula columbiana
Navicula columnaris
Navicula comerei
Navicula commixta
Navicula commutabilis
Navicula commutata
Navicula comoides
Navicula compacta
Navicula compar
Navicula comperei
Navicula complanata
Navicula complanatoides
Navicula completa 1
Navicula completaoides
Navicula compositestriata
Navicula compressicauda
Navicula concamerata
Navicula concentrica
Navicula concilians
Navicula concinna
Navicula confecta
Navicula confervacea
Navicula confidens
Navicula congerana
Navicula congolensis
Navicula congrua
Navicula conjugata
Navicula conjuncta
Navicula connectens
Navicula conops
Navicula consanguinea
Navicula conscensa
Navicula consentanea
Navicula consimilis
Navicula consors
Navicula conspersa
Navicula constans
Navicula constantinii
Navicula constricta
Navicula contempta
Navicula contenta
Navicula contentaeformis
Navicula contermina
Navicula contigua
Navicula contorta
Navicula contortula
Navicula contracta
Navicula contraria
Navicula controversa
Navicula conveniens
Navicula convergens
Navicula conveyi
Navicula copiosa
Navicula coquedensis
Navicula coraliana
Navicula corbieri
Navicula cordillerae
Navicula cornubiensis
Navicula coronensis
Navicula corpulenta
Navicula correpta
Navicula corrugata
Navicula cortanensis
Navicula corticola
Navicula corymbosa
Navicula cosmaria
Navicula costata
Navicula costei
Navicula costulata
Navicula costuloides
Navicula cotiformis
Navicula couperi
Navicula crabro
Navicula crabroniformis
Navicula crassirostris
Navicula crassula
Navicula crassulexigua
Navicula crassuliexigua
Navicula crateri
Navicula craticula
Navicula craticularis
Navicula craveni
Navicula creguti
Navicula cremeri
Navicula cremorne
Navicula crepitacula
Navicula creuzbergensis
Navicula criophila
Navicula crispa
Navicula cristula
Navicula crocodili
Navicula cronullensis
Navicula crucialis
Navicula cruciata
Navicula crucifera
Navicula crucifix
Navicula cruciformis
Navicula crucigera
Navicula crucigeriformis
Navicula crux
Navicula cruxmeridionalis
Navicula cryophila
Navicula cryptocephala
Navicula cryptocephaloides
Navicula cryptofallax
Navicula cryptonella
Navicula cryptorrhynchus
Navicula cryptostriata
Navicula cryptotenella
Navicula cryptotenelloides
Navicula csaszkaae
Navicula cubitus
Navicula cumbriensis
Navicula cumvibia
Navicula cunctans
Navicula curiosa
Navicula cursoria
Navicula curta
Navicula curtestria
Navicula curtisterna
Navicula curvilineata
Navicula curvinervia
Navicula curvipunctata
Navicula cuspidata
Navicula cuspis
Navicula cuvella
Navicula cyclophora
Navicula cyclops
Navicula cymatopleura
Navicula cymbelliformis
Navicula cymbelloides
Navicula cymbula
Navicula cyprinus
Navicula czekehazensis
D
Navicula dactylus
Navicula dahomensis
Navicula dahurica
Navicula dailyi
Navicula dalmatica
Navicula damasii
Navicula damongensis
Navicula dariana
Navicula dartevellei
Navicula darwiniana
Navicula davidsoniana
Navicula de-toniana
Navicula de-wittiana
Navicula dealpina
Navicula debegenica
Navicula debilis
Navicula debilissima
Navicula debilitata
Navicula deblockii
Navicula debyi
Navicula dechambrei
Navicula decipiens
Navicula decissa
Navicula declinata
Navicula decora
Navicula decrescens
Navicula decumana
Navicula decurrens
Navicula decussata
Navicula decussepunctata
Navicula definita
Navicula defluens
Navicula degenii
Navicula dehissa
Navicula delastriata
Navicula delata
Navicula delawarensis
Navicula delecta
Navicula delginensis
Navicula deliberata
Navicula delicata
Navicula delognei
Navicula delpiroui
Navicula delta
Navicula deltaica
Navicula demerara
Navicula demerarae
Navicula demeraroides
Navicula demissa
Navicula demta
Navicula denizotii
Navicula densa
Navicula denselineolata
Navicula densepunctata
Navicula densestriata
Navicula densilineolata
Navicula densistriata
Navicula densuensis
Navicula denticulata
Navicula denudata
Navicula depauxii
Navicula depressa
Navicula derasa
Navicula descripta
Navicula deserti
Navicula destituta
Navicula detenta
Navicula detersa
Navicula diabolica
Navicula diaculus
Navicula diagonalis
Navicula diahotana
Navicula diaphana
Navicula diaphanea
Navicula dibola
Navicula dicephala
Navicula dicurvata
Navicula didyma
Navicula diengensis
Navicula differta
Navicula difficilis
Navicula difficillima
Navicula difficillimoides
Navicula diffluens
Navicula difformis
Navicula diffusa
Navicula dificilis
Navicula digito
Navicula digito-radiata
Navicula digitoconvergens
Navicula digitoradiata
Navicula digitulus
Navicula digna
Navicula digrediens
Navicula digtoradiata
Navicula dilata
Navicula dilatata
Navicula dilucida
Navicula dimidiata
Navicula diomphala
Navicula diploneiformis
Navicula diplosticta
Navicula directa
Navicula dirhynchus
Navicula dirrhombus
Navicula discernenda
Navicula disclusa
Navicula discrepans
Navicula disertoides
Navicula disjuncta
Navicula disjunctoides
Navicula dispar
Navicula disparalis
Navicula disparata
Navicula dispensata
Navicula dispersa
Navicula dispersepunctata
Navicula dispersepunctulata
Navicula disposita
Navicula disputans
Navicula dissimilis
Navicula dissipata
Navicula dissipata
Navicula dissuta
Navicula distans
Navicula distantepunctata
Navicula distauridium
Navicula distenta
Navicula disticha
Navicula distincta
Navicula distinctastriata
Navicula distoma
Navicula diuturna
Navicula diuturnoides
Navicula divaricata
Navicula divergens
Navicula diversa
Navicula diversestriata
Navicula diversipunctata
Navicula diversistriata
Navicula diverta
Navicula dobrinatemniskovae
Navicula dodowaensis
Navicula doehleri
Navicula doello-juradoi
Navicula doeringii
Navicula doljensis
Navicula dolosa
Navicula dolosa
Navicula donkinia
Navicula dorenbergi
Navicula dorogostaiskyi
Navicula dosseti-azpeitia
Navicula dubia
Navicula dubitata
Navicula dubravicensis
Navicula duerrenbergiana
Navicula dugaensis
Navicula dulcioides
Navicula dulcis
Navicula dumontiae
Navicula dunstonii
Navicula duomedia
Navicula duplex
Navicula duplicata
Navicula duplocapitata
Navicula durandii
Navicula dutoitana
Navicula dux
Navicula dvorachekii
Navicula dystrophica
E
Navicula ebor
Navicula eburnea
Navicula ectoris
Navicula effrenata
Navicula egena
Navicula egeria
Navicula egregia
Navicula egyptiaca
Navicula ehrenbergii
Navicula ehrlichiae
Navicula eichhorniaephila
Navicula eichhorniophila
Navicula eidrigeana
Navicula eiowana
Navicula ekholmensis
Navicula el-kab
Navicula elaborata
Navicula elaphros
Navicula electa
Navicula electrolytifuga
Navicula elegans
Navicula elegantissima
Navicula elegantoides
Navicula elegantula
Navicula elenkinii
Navicula elephantis
Navicula elesdiana
Navicula elevata
Navicula elginensis
Navicula elkab
Navicula ellips
Navicula ellipsis
Navicula elliptica
Navicula elmorei
Navicula elongata
Navicula elongatula
Navicula elpatievskyi
Navicula elsae-thum
Navicula elsoniana
Navicula emarginata
Navicula endophytica
Navicula engelbrechtii
Navicula ennediensis
Navicula entoleia
Navicula entomon
Navicula entzii
Navicula enucleata
Navicula eocaenica
Navicula episcopalis
Navicula eponka
Navicula epsilon
Navicula equiornata
Navicula erdmannensis
Navicula ergadensis
Navicula erifuga
Navicula erosa
Navicula erythraea
Navicula esamangensis
Navicula escambia
Navicula esoculus
Navicula esox
Navicula eta
Navicula eugeniae
Navicula eumontana
Navicula euryale
Navicula eurycephala
Navicula eurysoma
Navicula evexa
Navicula evulsa
Navicula exasperans
Navicula excavata
Navicula excavata
Navicula excellens
Navicula excentrica
Navicula excepta
Navicula exemta
Navicula exigua
Navicula exiguiformis
Navicula exiguoides
Navicula exiguoidis
Navicula exiliformis
Navicula exilior
Navicula exilis
Navicula exilissima
Navicula exillima
Navicula eximia
Navicula expecta
Navicula expectilis
Navicula expedita
Navicula expeditionis
Navicula explanata
Navicula expleta
Navicula explicata
Navicula explicatoides
Navicula explorata
Navicula eymei
F
Navicula faba
Navicula faceta
Navicula facilis
Navicula falaisiensis
Navicula falax
Navicula falklandiae
Navicula fallax
Navicula falsalyra
Navicula famintzinii
Navicula faoensis
Navicula farakulumensis
Navicula farcimen
Navicula farta
Navicula fasciata
Navicula fatigans
Navicula fauta
Navicula fawumangensis
Navicula febigeri
Navicula febigerii
Navicula fennica
Navicula fennoscandica
Navicula fernandae
Navicula fernandesii
Navicula fernandi-koburg
Navicula ferrazae
Navicula festiva
Navicula feuerborni
Navicula feuerbornii
Navicula filarszkyana
Navicula filarszkyi
Navicula filholi
Navicula filiformis
Navicula finitima
Navicula finmarchica
Navicula finnmarchica
Navicula firma
Navicula fischeri
Navicula flabellata
Navicula flagellifera
Navicula flahaulti
Navicula flamma
Navicula flammarionensis
Navicula flammula
Navicula flanatica
Navicula flattii
Navicula flebilis
Navicula flexuosa
Navicula florentina
Navicula floridae
Navicula floridana
Navicula florinae
Navicula floriniae
Navicula fluens
Navicula fluitans
Navicula fluminensis
Navicula fluminisirtysch
Navicula fluminitica
Navicula fluviae-jenisseyi
Navicula foliola
Navicula folium
Navicula fontana
Navicula fontellii
Navicula fonticola
Navicula fontinalis
Navicula forcipata
Navicula formenterae
Navicula formicata
Navicula formicina
Navicula formosa
Navicula fortis
Navicula fortunata
Navicula fossilioides
Navicula fossilis
Navicula fragilarioides
Navicula fragilis
Navicula franciscae
Navicula frasnensis
Navicula fraudulenta
Navicula freesei
Navicula frenguellii
Navicula frequens
Navicula frickei
Navicula frickei
Navicula friesneri
Navicula frigida
Navicula frisiae
Navicula friska
Navicula fromenterae
Navicula frugalis
Navicula frustuliaeformis
Navicula frustuloides
Navicula fuchsii
Navicula fuegiana
Navicula fuegiana
Navicula fuenzalidae
Navicula fukiensis
Navicula fundata
Navicula funiculata
Navicula furtiva
Navicula fusca
Navicula fuscata
Navicula fusidium
Navicula fusiformis
Navicula fusiformis-vahliana
Navicula fusioides
Navicula fustis
Navicula fusus
Navicula futilis
G
Navicula galapagoensis
Navicula galea
Navicula galikii
Navicula gallapagensis
Navicula gallica
Navicula galvagensis
Navicula gamma
Navicula gandhii
Navicula gandrupi
Navicula garganica
Navicula garkeana
Navicula gasilidei
Navicula gastriformis
Navicula gastroides
Navicula gastrum
Navicula gauthieri
Navicula gebhardi
Navicula gebhardii
Navicula geinitzi
Navicula geisslerae
Navicula geitleri
Navicula gelida
Navicula gemina
Navicula geminata
Navicula gemmata
Navicula gemmatula
Navicula gemmeta
Navicula gendrei
Navicula genevensis
Navicula geniculata
Navicula genifera
Navicula genovefae
Navicula genustriata
Navicula gerloffi
Navicula gerloffii
Navicula germanopolonica
Navicula geronimensis
Navicula gibba
Navicula gibberula
Navicula gibbosa
Navicula giebelii
Navicula gieskesii
Navicula gigantorum
Navicula gigas
Navicula gilva
Navicula girodi
Navicula girondica
Navicula glaberrima
Navicula glaberrimum
Navicula glabra
Navicula glabrissima n
Navicula glabriuscula
Navicula glacialis
Navicula glaciei
Navicula glangeaudi
Navicula glans
Navicula glasovii
Navicula globiceps
Navicula globifera
Navicula globosa
Navicula globosaoides
Navicula globulifera
Navicula globuliferiformis
Navicula glomus
Navicula gloriosa
Navicula gloriosa
Navicula godfroyi
Navicula goeppertiana
Navicula goersii
Navicula gomontiana
Navicula gomphonemacea
Navicula gomphonemoides
Navicula gondwana
Navicula gonzalvesiana
Navicula gordonii
Navicula gorjanovicii
Navicula gothlandica
Navicula gotlandica
Navicula gottlandica
Navicula gourdonii
Navicula gouwsii
Navicula gracilis
Navicula gracillima
Navicula graciloides
Navicula gradata
Navicula gradatoides
Navicula graeffii
Navicula gralana
Navicula grammitis
Navicula granii
Navicula granoryza
Navicula granulata
Navicula granulifer
Navicula granum
Navicula granum-avenae
Navicula grasmueckii
Navicula grata
Navicula gratissima
Navicula gregaria
Navicula gregaria
Navicula gregaria
Navicula gregarioides
Navicula gregoriana
Navicula gregorii
Navicula gretharum
Navicula grevilleana
Navicula grevillei
Navicula grevilleoides
Navicula grevillii
Navicula grimmei
Navicula grimmeioides
Navicula grimmii
Navicula grimmioides
Navicula grippii
Navicula groenlandica
Navicula groschopfi
Navicula groschopfii
Navicula grovei
Navicula grudeensis
Navicula gruendleri
Navicula gruendleriana
Navicula grundtvigii
Navicula grunovii
Navicula grunowii
Navicula guadalupensis
Navicula guarujana
Navicula guatemalensis
Navicula guaynaboensis
Navicula guetharyana
Navicula guihotii
Navicula guinardiana
Navicula guluensis
Navicula gurovii
Navicula guttata
Navicula guttulifera
Navicula gutwinskii
Navicula gyrinida
Navicula gysigensis
H
Navicula h-album
Navicula habena
Navicula habita
Navicula hagelsteinii
Navicula hahni
Navicula hahnii
Navicula halinae
Navicula halionata
Navicula halophila
Navicula halophiloides
Navicula hamiltonii
Navicula hamulifera
Navicula hangchowensis
Navicula hankae
Navicula hanseatica
Navicula hanseniana
Navicula hantkenii
Navicula haradaae
Navicula harbinensis
Navicula harderi
Navicula harpa
Navicula harrisoniana
Navicula hartii
Navicula hartzii
Navicula hasta
Navicula hastaeformis
Navicula hastata
Navicula hastatula
Navicula hauckii
Navicula haueri
Navicula hawaiensis
Navicula hawaiiensis
Navicula haynaldii
Navicula haytiana
Navicula hazslinszkyi
Navicula hebes
Navicula hecateia
Navicula heeri
Navicula heilprinensis
Navicula heimansioides
Navicula heimii
Navicula helea
Navicula helensoides
Navicula helmandensis
Navicula helminae
Navicula helvetica
Navicula hemiptera
Navicula hemiviridula
Navicula henckeli
Navicula hennedyi
Navicula hennedyii
Navicula henriquesii
Navicula herbstiae
Navicula heribaudi
Navicula hermanii
Navicula heteroflexa
Navicula heterostriata
Navicula heterovalvata
Navicula heufleri
Navicula heufleriana
Navicula hevesensis
Navicula hexapla
Navicula hibernica
Navicula hilarula
Navicula hilliardi
Navicula hilliardii
Navicula hintzii
Navicula hirudo
Navicula hitchcocki
Navicula hochstetteri
Navicula hochstetteriana
Navicula hodgeana
Navicula hoefleri
Navicula hoeflerii
Navicula hoffmannii
Navicula hofmanniae
Navicula hollandica
Navicula hollerupensis
Navicula holmiensis
Navicula holstii
Navicula holubyi
Navicula homburgiana
Navicula hordeiformis
Navicula hornigii
Navicula horstii
Navicula hospes
Navicula huei
Navicula hugenottarum
Navicula humboldtiana
Navicula humerosa arabica
Navicula humjibreensis
Navicula hungarica
Navicula huniensis
Navicula husi
Navicula hustedtiana
Navicula hustedtii
Navicula hyalina
Navicula hyalina
Navicula hyalosira
Navicula hybrida
Navicula hyperborea
Navicula hyrtlii
I
Navicula iasnitskii
Navicula iberica
Navicula icostauron
Navicula ignobilis
Navicula ignota
Navicula ikari
Navicula illicita
Navicula illinoensis
Navicula illustra
Navicula illustris
Navicula ilopangoensis
Navicula imbecilla
Navicula imbellis
Navicula impangenica
Navicula imperfecta
Navicula imperialis
Navicula impertila
Navicula impexa
Navicula implana
Navicula impossibilis
Navicula impressa
Navicula inattigens
Navicula incarum
Navicula incisa
Navicula inclinata
Navicula includens
Navicula incognita
Navicula incomitatus
Navicula incomperta
Navicula incomposita
Navicula incongruens
Navicula incudiformis
Navicula inculta
Navicula incurva
Navicula incus
Navicula indefinita
Navicula indemnis
Navicula index
Navicula indianensis
Navicula indica
Navicula indigens
Navicula inducens
Navicula indulgens
Navicula inelegans
Navicula inexacta
Navicula inexpectans
Navicula inexplorata
Navicula infaceta
Navicula infirma
Navicula infirmata
Navicula infirmitata
Navicula inflasa
Navicula inflata
Navicula inflatoides
Navicula inflexa
Navicula infrenis
Navicula ingapirca
Navicula ingens
Navicula ingenua
Navicula ingoldii
Navicula ingrata
Navicula ingstadii
Navicula ingustata
Navicula inhalata
Navicula inhalata
Navicula injusta
Navicula innommata
Navicula inornata
Navicula inpunctata
Navicula inquisitor
Navicula inscendens
Navicula insepta
Navicula insequens
Navicula inserata
Navicula inseriata
Navicula insignificans
Navicula insignis
Navicula insignita
Navicula insociabilis
Navicula insolita
Navicula insolubilis
Navicula insularis
Navicula insulsa
Navicula insuta
Navicula intacta
Navicula integra
Navicula intercedens
Navicula interglacialis
Navicula interlineata
Navicula intermedia
Navicula intermixta
Navicula interrupta
Navicula interruptestriata
Navicula intractata
Navicula intricata
Navicula inutilis
Navicula invenusta
Navicula inversa
Navicula invicta
Navicula invisitata
Navicula involata
Navicula involuta
Navicula iota
Navicula iranensis
Navicula irata
Navicula ireneae
Navicula iridis
Navicula irmengardis
Navicula irregularis
Navicula irreversa
Navicula irritans
Navicula irrorata
Navicula irroratoides
Navicula isabelensiformis
Navicula isabelensiminor
Navicula isabelensis
Navicula isabelensoides
Navicula iserentantii
Navicula isertii
Navicula islandica
Navicula isocephala
Navicula isostauron
Navicula iversenii
Navicula ivigtutensis
Navicula izsopallagae
J
Navicula jacobii
Navicula jacotiae
Navicula jaernefeltioides
Navicula jakkalsica
Navicula jakovljevici
Navicula jakovljevicii
Navicula jamaicensis
Navicula jasnitskii
Navicula jasnitskyi
Navicula jatobensis
Navicula javanensis
Navicula javanica
Navicula jeffreyae
Navicula jejuna
Navicula jejunoides
Navicula jejunoides
Navicula jenneri
Navicula jentzschii
Navicula jequitinhonhae
Navicula jessenii
Navicula jimboi
Navicula jogensis
Navicula johanrossii
Navicula johnsonii
Navicula jonssoni
Navicula jonssonii
Navicula jordani
Navicula josephi
Navicula joubaudi
Navicula joubaudii
Navicula joursacensis
Navicula jouseana
Navicula juanitalinda
Navicula juba
Navicula jucunda
Navicula jucunda
Navicula jugata
Navicula julieni
Navicula jungi
Navicula jungii
Navicula jurassensis
Navicula jurgensii
Navicula jurilji
K
Navicula kaapensis
Navicula kaelfvensis
Navicula kaikonkiensis
Navicula kamorthensis
Navicula kanemi
Navicula kanitzii
Navicula kantsiensis
Navicula kappa
Navicula karelica
Navicula kariana
Navicula karsia
Navicula karstenii
Navicula kawamurae
Navicula kefvingensis
Navicula kelleri
Navicula kenon
Navicula kenyae
Navicula kepesii
Navicula kerguelensis
Navicula kernensis
Navicula kertschiana
Navicula kincaidii
Navicula kinkeriana
Navicula kinkerii
Navicula kirchneriana
Navicula kisber
Navicula kittoniana
Navicula kizakensis
Navicula kjellmanii
Navicula klavsenii
Navicula kleerekoperi
Navicula knysnensis
Navicula knysnesis
Navicula kochii
Navicula koeiei
Navicula kohlenbachii
Navicula kohlmaieri
Navicula kolbei
Navicula kolentiensis
Navicula kolugoensis
Navicula koniamboensis
Navicula konstantini
Navicula korzeniewskii
Navicula kossuthii
Navicula kotschii
Navicula kotschyana
Navicula kotschyi
Navicula kovalchookiana
Navicula kpongensis
Navicula krammerae
Navicula krasskei
Navicula krookii
Navicula kryokonites
Navicula kryophila
Navicula kuetzingiana
Navicula kuetzingii
Navicula kuolensis
Navicula kuripanensis
Navicula kurzii
Navicula kuseliana
Navicula kutzingiana
Navicula kuusamensis
Navicula kuwaitiana
Navicula kwamkuji
Navicula laciniosa
L
Navicula laciniosa
Navicula lacrimans
Navicula lacrymans
Navicula lacuna
Navicula lacunarum
Navicula lacunicola
Navicula lacus-karluki
Navicula lacus-baicali
Navicula lacus-lemani
Navicula lacustris
Navicula ladogensis
Navicula laevimarginata
Navicula laevis
Navicula laevissima
Navicula lagerheimii
Navicula lagerstedti
Navicula lagunae
Navicula laingii
Navicula lalia
Navicula lambda
Navicula lambertensis
Navicula lamella
Navicula lamii
Navicula lampra
Navicula lamprocampa
Navicula lanceolata
Navicula langoraensis
Navicula lapidosa
Navicula lapila
Navicula lapsa
Navicula lata
Navicula latefasciata
Navicula latelongitudinalis
Navicula lateropunctata
Navicula laterostrata
Navicula latevittata
Navicula laticeps
Navicula latissima
Navicula lauca
Navicula lauta
Navicula lawsonii
Navicula le-tourneurii
Navicula leboimei
Navicula leemanniae
Navicula lefevrei
Navicula legumen
Navicula lehmanniae
Navicula leistikowii
Navicula lemmermanni
Navicula lemmermannii
Navicula lenis
Navicula lenoblei
Navicula lenticula
Navicula lenzi
Navicula leonardi
Navicula leonardii
Navicula leonis
Navicula lepida
Navicula lepta
Navicula leptoceros
Navicula leptoloba
Navicula leptorhynchus
Navicula leptostigma
Navicula leptostriata
Navicula leptostylus
Navicula leptotermia
Navicula lesinensis
Navicula lesothensis
Navicula letulenta
Navicula leudugeri
Navicula levanderi
Navicula leveillei
Navicula levensis
Navicula levis
Navicula liaotungiensis
Navicula libellus
Navicula liber
Navicula libonensis
Navicula liburnica
Navicula lignieri
Navicula limanense
Navicula limata
Navicula limatoides
Navicula limbata
Navicula limicola
Navicula limitanea
Navicula limosa
Navicula limpida
Navicula lindae
Navicula lineola
Navicula lineostriata
Navicula linter
Navicula liostauron
Navicula liouvillei
Navicula lirata
Navicula lithognatha
Navicula lithognathoides
Navicula litoris
Navicula litos
Navicula littoralis
Navicula ljugneri
Navicula ljungneri
Navicula lobata
Navicula loczyi
Navicula lohmannii
Navicula loibl-sittlerii
Navicula lomastriata
Navicula londonensis
Navicula longa
Navicula longi
Navicula longicephala
Navicula longifissa
Navicula longirostris
Navicula longistriata
Navicula lorcana
Navicula lorenzii
Navicula lovenii
Navicula loveridgei
Navicula lubetii
Navicula lucenoides
Navicula lucentiformis
Navicula luciae A.Witkowski
Navicula luciana
Navicula lucida
Navicula lucidula
Navicula lucifica
Navicula ludloviana
Navicula luisii
Navicula lumbricastriata
Navicula lumen
Navicula lunata
Navicula lunatapicalis
Navicula lundii
Navicula lundstroemii
Navicula lunula
Navicula lunulifera
Navicula lunyacsekii
Navicula lupula
Navicula lurinda
Navicula lusitanica
Navicula lusoria
Navicula luxoriensis
Navicula luxuriosa
Navicula luzonensis
Navicula lybica
Navicula lyra
Navicula lyrans
Navicula lyrella
Navicula lyrigera
Navicula lyroides
M
Navicula macdonaghi
Navicula macer
Navicula maceria
Navicula macilenta
Navicula macraeana
Navicula macrogongyla
Navicula macromphala
Navicula macropunctata
Navicula macula
Navicula maculata
Navicula maculosa
Navicula madagascarensis
Navicula madagascariensis
Navicula madeirensis
Navicula madrae
Navicula maeandriana
Navicula maeandrinoides
Navicula maendrina
Navicula maeotica
Navicula magapolitana
Navicula magellanica
Navicula magna
Navicula magnifica
Navicula maharashtrensis
Navicula mahoodii
Navicula maidanae
Navicula major
Navicula malacarae
Navicula maliana
Navicula malica
Navicula malinvaudi
Navicula malombensis
Navicula malutiana
Navicula mammalis
Navicula manapiensis
Navicula manginii
Navicula manifesta
Navicula mannii
Navicula manokwariensis
Navicula mansiensis
Navicula mantichora
Navicula manubialis
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Navicula margalithii
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Navicula margaritacea
Navicula margaritata
Navicula margaritiana
Navicula marginata
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Navicula margino-nodularis
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Navicula mastogloidea
Navicula mauleri
Navicula mauriciana
Navicula maxima
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Navicula meadeensis
Navicula meadensis
Navicula mediacomplexa
Navicula mediahelos
Navicula medica
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Navicula mimicans
Navicula mimula
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Navicula multicostata
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Navicula my
N
Navicula nadjae
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Navicula neglecta
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Navicula normalis
Navicula normaloides
Navicula northumbrica
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Navicula notha
Navicula novae-guineaensis
Navicula novaesiberica
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Navicula nugalis
Navicula nungaensis
O
Navicula oahuensis
Navicula obesa
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Navicula oetzvallensis
Navicula ognjanovae
Navicula ohiensis
Navicula okunoi
Navicula oliffi
Navicula oligotraphenta
Navicula onoensis
Navicula opieorum
Navicula opima
Navicula opportuna
Navicula oppugnata
Navicula orangiana
Navicula orbiculata
Navicula orbis
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Navicula ovalis
Navicula ovata
P
Navicula paanaensis
Navicula paca
Navicula pacardi
Navicula pagophila
Navicula palearctica
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Navicula pelagica
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Navicula pennata
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Navicula pseudohumilis
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Navicula pseudolagerheimii
Navicula pseudolanceolata
Navicula pseudolinearis
Navicula pseudolitoricola
Navicula pseudolucidula
Navicula pseudomenisculus
Navicula pseudoorthoneoides
Navicula pseudopalpebralis
Navicula pseudopelliculosa
Navicula pseudoppugnata
Navicula pseudoreinhardtii
Navicula pseudosalinarioides
Navicula pseudo-schoenfeldii
Navicula pseudosilicula
Navicula pseudostrearia
Navicula pseudostundii
Navicula pseudotenelloides
Navicula pseudotenelloides
Navicula pseudotenelloides
Navicula pseudothienemannii
Navicula pulchripora
Navicula pungens
Navicula pusilloides
Q-R
Navicula quadrisinuata
Navicula quadriundulata
Navicula quasidisjuncta
Navicula quaternaria
Navicula quechua
Navicula quincunx
Navicula quinquenodis
Navicula radians
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Navicula radiosa
Navicula radiosafallax
Navicula radiosiola
Navicula radiostriata
Navicula rainierensis
Navicula rajmundii
Navicula rakowskae
Navicula ramosissima
Navicula raphoneis
Navicula ravinae
Navicula recava
Navicula recens
Navicula recognita
Navicula recondita
Navicula rectiformis
Navicula rectum
Navicula regata
Navicula regelli
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Navicula reichardtiana
Navicula reimeri
Navicula reinhardtii
Navicula reinickeana
Navicula reissii
Navicula relicta
Navicula resecta
Navicula restitua
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Navicula retusa
Navicula rhodana
Navicula rhombica
Navicula rhynchocephala
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Navicula ricardae
Navicula ricardii
Navicula ridelii
Navicula riediana
Navicula riotecensis
Navicula rivalis
Navicula rivularis
Navicula rivulorum
Navicula rogalli
Navicula rolandii
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Navicula rotaeana
Navicula rotaena
Navicula rotula
Navicula ruga
Navicula rumaniensis
Navicula rusticensis
S
Navicula sabae
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Navicula sarcophagus
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Navicula salinarum
Navicula salinicola
Navicula sanctacrux
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Navicula savannahiana
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Navicula scirpus
Navicula scoliopleuroides
Navicula scoresbyi
Navicula scotica
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Navicula scutum
Navicula seductilis
Navicula seibigiana
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Navicula seippiana
Navicula sejuncta
Navicula semen
Navicula semenicula
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Navicula semiarea
Navicula semihyalina
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Navicula seminuloides
Navicula semivirgata
Navicula senegalensis
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Navicula septenaria
Navicula septentrionalis
Navicula sequens
Navicula serdicensis
Navicula serotina
Navicula shanwangensis
Navicula shiloi
Navicula siamexilis
Navicula siamlinearis
Navicula sibirica
Navicula sieminskiae
Navicula sigma
Navicula silenda
Navicula silens
Navicula simplex
Navicula simplexoides
Navicula simula
Navicula simulans
Navicula singularis
Navicula siofokensis
Navicula sjoersii
Navicula skabitchewskyayae
Navicula skabitschewskyi
Navicula skiftei
Navicula skuae
Navicula slesvicensis
Navicula slesvicensus
Navicula smeerenburgensis
Navicula smithii
Navicula söhrensis
Navicula solaris
Navicula solida
Navicula sorella
Navicula sovereignae
Navicula sovereignii
Navicula spartinetensis
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Navicula staurifera
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Navicula stoermeri
Navicula strangulata
Navicula streckerae
Navicula strelnikovae
Navicula strenzkii
Navicula striolata
Navicula structa
Navicula stuxbergii
Navicula subacuta
Navicula subadnata
Navicula subajajensis
Navicula subalpina
Navicula sub-bacillum
Navicula subbotnica
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Navicula subcancellata
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Navicula subconcentrica
Navicula subdelicata
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Navicula symmetrica
Navicula syvertsenii
Navicula szlachetkoi
T
Navicula taedens
Navicula tairuaensis
Navicula tamnaeana
Navicula tanakae
Navicula tantula
Navicula taylorii
Navicula temniskovae
Navicula tenelloides
Navicula tenuicephala
Navicula tenuipunctata
Navicula tenuis (now Adlafia tenuis
Navicula termes
Navicula terricola
Navicula tersa
Navicula testa
Navicula testata
Navicula texana
Navicula theelii
Navicula theinemannii
Navicula thienemannii
Navicula thiennemanii
Navicula thoroddsenii
Navicula tibetica
Navicula toba
Navicula torellii
Navicula torganae
Navicula torneensis
Navicula toulaae
Navicula toxa
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Navicula tranciloba
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Navicula transitans
Navicula tranversa
Navicula traucilola
Navicula triconfusa
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Navicula triumvirorum
Navicula trivialis
Navicula trochus
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Navicula tropicoidea
Navicula tsetsegmaae
Navicula tubulosa
Navicula turris
Navicula tuulensis
Navicula tuzoni
Navicula twymania
Navicula twymanniana
U-V
Navicula udintsevii
Navicula ultratenelloides
Navicula umbra
Navicula umkantziensis
Navicula undosa
Navicula undulata
Navicula undulata
Navicula unilaterarea
Navicula uniseriata
Navicula usoltsevae
Navicula utermoehlii
Navicula utlandshoerniensis
Navicula vacillans
Navicula vahlii
Navicula valdestriata
Navicula valdicostata
Navicula valeriana
Navicula validicostata
Navicula vandamii
Navicula vaneei
Navicula vanei
Navicula vanhoeffenii
Navicula vanmeeli
Navicula vara
Navicula varians
Navicula variolinea
Navicula vaupelli
Navicula vekhovii
Navicula venerablis
Navicula venetiformis
Navicula venetoides
Navicula ventricosa
Navicula verecundoides
Navicula vetita
Navicula vicina
Navicula vilaplanii
Navicula viminea
Navicula virgata
Navicula viridis
Navicula viridis
Navicula viridula
Navicula viridulacalcis
Navicula virihensis
Navicula virosa
Navicula vixcylindrata
Navicula vula
Navicula vulpina
W-Z
Navicula waernensis
Navicula walkeri
Navicula wardii
Navicula wasmundii
Navicula weberi
Navicula wendlingii
Navicula wetzelii
Navicula whitefishensis
Navicula wiesneri
Navicula wilczekii
Navicula wildii
Navicula willisiae
Navicula winona
Navicula wisei
Navicula woltereckii
Navicula worochinii
Navicula wrightii
Navicula wulfii
Navicula wunsamiae
Navicula wygaschii
Navicula yaarensis
Navicula zachariasii
Navicula zanonii
Navicula zeta
Navicula zichyi
Navicula zohdyi
Navicula zostereti
Navicula zsivnyana
References
Further reading
Lists of algae
Taxonomic lists (species) | List of Navicula species | Biology | 16,144 |
627,501 | https://en.wikipedia.org/wiki/Littlewood%20conjecture | In mathematics, the Littlewood conjecture is an open problem () in Diophantine approximation, proposed by John Edensor Littlewood around 1930. It states that for any two real numbers α and β,
where is the distance to the nearest integer.
Formulation and explanation
This means the following: take a point (α, β) in the plane, and then consider the sequence of points
(2α, 2β), (3α, 3β), ... .
For each of these, multiply the distance to the closest line with integer x-coordinate by the distance to the closest line with integer y-coordinate. This product will certainly be at most 1/4. The conjecture makes no statement about whether this sequence of values will converge; it typically does not, in fact. The conjecture states something about the limit inferior, and says that there is a subsequence for which the distances decay faster than the reciprocal, i.e.
o(1/n)
in the little-o notation.
Connection to further conjectures
It is known that this would follow from a result in the geometry of numbers, about the minimum on a non-zero lattice point of a product of three linear forms in three real variables: the implication was shown in 1955 by Cassels and Swinnerton-Dyer. This can be formulated another way, in group-theoretic terms. There is now another conjecture, expected to hold for n ≥ 3: it is stated in terms of G = SLn(R), Γ = SLn(Z), and the subgroup D of diagonal matrices in G.
Conjecture: for any g in G/Γ such that Dg is relatively compact (in G/Γ), then Dg is closed.
This in turn is a special case of a general conjecture of Margulis on Lie groups.
Partial results
Borel showed in 1909 that the exceptional set of real pairs (α,β) violating the statement of the conjecture is of Lebesgue measure zero. Manfred Einsiedler, Anatole Katok and Elon Lindenstrauss have shown that it must have Hausdorff dimension zero; and in fact is a union of countably many compact sets of box-counting dimension zero. The result was proved by using a measure classification theorem for diagonalizable actions of higher-rank groups, and an isolation theorem proved by Lindenstrauss and Barak Weiss.
These results imply that non-trivial pairs satisfying the conjecture exist: indeed, given a real number α such that , it is possible to construct an explicit β such that (α,β) satisfies the conjecture.
See also
Littlewood polynomial
References
Further reading
Diophantine approximation
Conjectures
Unsolved problems in mathematics | Littlewood conjecture | Mathematics | 557 |
27,459,313 | https://en.wikipedia.org/wiki/C38H42N2O6 | {{DISPLAYTITLE:C38H42N2O6}}
The molecular formula C38H42N2O6 (molar mass : 622.74 g/mol) may refer to :
Cycleanine, a selective vascular calcium antagonist
Rodiasine, an alkaloid
Tetrandrine, a calcium channel blocker | C38H42N2O6 | Chemistry | 74 |
77,405,256 | https://en.wikipedia.org/wiki/Fradkin%20tensor | The Fradkin tensor, or Jauch-Hill-Fradkin tensor, named after Josef-Maria Jauch and Edward Lee Hill and David M. Fradkin, is a conservation law used in the treatment of the isotropic multidimensional harmonic oscillator in classical mechanics. For the treatment of the quantum harmonic oscillator in quantum mechanics, it is replaced by the tensor-valued Fradkin operator.
The Fradkin tensor provides enough conserved quantities to make the oscillator's equations of motion maximally superintegrable. This implies that to determine the trajectory of the system, no differential equations need to be solved, only algebraic ones.
Similarly to the Laplace–Runge–Lenz vector in the Kepler problem, the Fradkin tensor arises from a hidden symmetry of the harmonic oscillator.
Definition
Suppose the Hamiltonian of a harmonic oscillator is given by
with
momentum ,
mass ,
angular frequency , and
displacement ,
then the Fradkin tensor (up to an arbitrary normalisation) is defined as
In particular, is given by the trace: . The Fradkin Tensor is a thus a symmetric matrix, and for an -dimensional harmonic oscillator has independent entries, for example 5 in 3 dimensions.
Properties
The Fradkin tensor is orthogonal to the angular momentum :
contracting the Fradkin tensor with the displacement vector gives the relationship
.
The 5 independent components of the Fradkin tensor and the 3 components of angular momentum give the 8 generators of , the three-dimensional special unitary group in 3 dimensions, with the relationships
where is the Poisson bracket, is the Kronecker delta, and is the Levi-Civita symbol.
Proof of conservation
In Hamiltonian mechanics, the time evolution of any function defined on phase space is given by
,
so for the Fradkin tensor of the harmonic oscillator,
.
The Fradkin tensor is the conserved quantity associated to the transformation
by Noether's theorem.
Quantum mechanics
In quantum mechanics, position and momentum are replaced by the position- and momentum operators and the Poisson brackets by the commutator. As such the Hamiltonian becomes the Hamiltonian operator, angular momentum the angular momentum operator, and the Fradkin tensor the Fradkin operator. All of the above properties continue to hold after making these replacements.
References
Quantum mechanics
Classical mechanics | Fradkin tensor | Physics | 487 |
69,607,031 | https://en.wikipedia.org/wiki/All%20Japan%20Chemistry%20Workers%27%20Union | The All Japan Chemistry Workers' Union (JCWU, , Zenkoku Kagaku) was a trade union representing workers in the chemical industry in Japan.
The union was founded on 20 October 1987, by 30 local unions which were expelled from the Japanese Federation of Synthetic Chemistry Workers' Unions (Goka Roren), due to an internal dispute. The union affiliated to the Japanese Trade Union Confederation, initially with 25,000 members, although by 1996, this had declined to only 10,540. In October 1998, the union merged with Goka Roren, to form the Japanese Federation of Chemistry Workers' Unions.
References
Chemical industry trade unions
Trade unions established in 1987
Trade unions disestablished in 1998
Trade unions in Japan | All Japan Chemistry Workers' Union | Chemistry | 148 |
17,753,349 | https://en.wikipedia.org/wiki/Chemical%20transport%20model | A chemical transport model (CTM) is a type of computer numerical model which typically simulates atmospheric chemistry and may give air pollution forecasting.
Chemical transport models and general circulation models
While related general circulation models (GCMs) focus on simulating overall atmospheric dynamics (e.g. fluid and heat flows), a CTM instead focuses on the stocks and flows of one or more chemical species. Similarly, a CTM must solve only the continuity equation for its species of interest, a GCM must solve all the primitive equations for the atmosphere; but a CTM will be expected to accurately represent the entire cycle for the species of interest, including fluxes (e.g. advection), chemical production/loss, and deposition. That being said, the tendency, especially as the cost of computing declines over time, is for GCMs to incorporate CTMs for species of special interest to climate dynamics, especially shorter-lived species such as nitrogen oxides and volatile organic compounds; this allows feedbacks from the CTM to the GCM's radiation calculations, and also allows the meteorological fields forcing the CTM to be updated at higher time resolution than may be practical in studies with offline CTMs.
Types of chemical transport models
CTMs may be classified according to their methodology and their species of interest, as well as more generic characteristics (e.g. dimensionality, degree of resolution).
Methodologies
Jacob (1999) classifies CTMs as Eulerian/"box" or Lagrangian/"puff" models, depending on whether the CTM in question focuses on
(Eulerian) "boxes" through which fluxes, and in which chemical production/loss and deposition occur over time
(Lagrangian) the production and motion of parcels of air ("puffs") over time
An Eulerian CTM solves its continuity equations using a global/fixed frame of reference, while a Lagrangian CTM uses a local/moving frame of reference.
See also
discussion of gridding in CLaMS
Lagrangian and Eulerian coordinates
discussion of the continuity equation in Jacob's Introduction to Atmospheric Chemistry online
Examples of Eulerian CTMs
CCATT-BRAMS
WRF-Chem
CMAQ, CMAQ Website
CAMx
GEOS-Chem
LOTOS-EUROS
MATCH
MOZART: (Model for OZone And Related chemical Tracers) is developed jointly by the (US) National Center for Atmospheric Research (NCAR), the Geophysical Fluid Dynamics Laboratory (GFDL), and the Max Planck Institute for Meteorology (MPI-Met) to simulate changes in ozone concentrations in the Earth's atmosphere. MOZART was designed to simulate tropospheric chemical and transport processes, but has been extended (MOZART3) into the stratosphere and mesosphere. It can be driven by standard meteorological fields from, for example, the National Centers for Environmental Prediction (NCEP), the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Global Modeling and Assimilation Office (GMAO), or by fields generated from general circulation models. MOZART4 improves MOZART2's chemical mechanisms, photolysis scheme, dry deposition mechanism, biogenic emissions and handling of tropospheric aerosols.
TOMCAT/SLIMCAT
CHIMERE
POLYPHEMUS
TCAM (Transport Chemical Aerosol Model; TCAM): a mathematical modelling method (computer simulation) designed to model certain aspects of the Earth's atmosphere. TCAM is one of several chemical transport models, all of which are concerned with the movement of chemicals in the atmosphere, and are thus used in the study of air pollution.
TCAM is a multiphase three-dimensional eulerian grid model (as opposed to lagrangian or other modeling methods). It is designed for modelling dispersion of pollutants (in particular photochemical and aerosol) at mesoscales (medium scale, generally concerned with systems a few hundred kilometers in size).
TCAM was developed at the University of Brescia in Italy.
Examples of Lagrangian CTMs
CLaMS
FLEXPART
Examples of Semi-Lagrangian CTMs
MOCAGE
GEM-MACH
Examples of ozone CTMs
CLaMS
MOZART
Notes
External links
MOZART:
UCAR's MOZART page
MPI-Met's MOZART page
Larry Horowitz's MOZART page
See also
Atmospheric dispersion modeling
List of atmospheric dispersion models
University Corporation for Atmospheric Research
National Center for Atmospheric Research
Ozone depletion
Meteorology
Numerical climate and weather models
Atmospheric dispersion modeling
Transport phenomena | Chemical transport model | Physics,Chemistry,Engineering,Environmental_science | 945 |
34,202,823 | https://en.wikipedia.org/wiki/Telstar%2014R | Telstar 14R, also known as Estrela do Sul 2 (Southern Star 2) is a commercial communications satellite in the Telstar series built by Space Systems/Loral for Telesat to provide Ku-band communications to South America and the Southern United States. It is a replacement for Telstar 14, whose north solar array failed to open after launch, limiting its mission effectiveness. Telstar 14R experienced the same problem, with its north solar array failing to open too, but is now in service despite that failure.
Launch
It was launched 20 May 2011 from the Baikonur Cosmodrome in Kazakhstan aboard an International Launch Services Proton-M rocket. Telstar 14R is built around the Loral 1300 satellite bus, and has a launch mass of around 5000 kg. It is positioned in geosynchronous orbit at 63 degrees west.
See also
2011 in spaceflight
References
External links
http://www.telesat.com/satellite-fleet/telstar/telstar-14r
http://space.skyrocket.de/doc_sdat/telstar-14r.htm
http://spaceflightnow.com/news/n1105/25telstar14r/index.html
http://www.nasaspaceflight.com/2011/05/live-ils-proton-m-launch-with-telstar-14r/
Telstar satellites
Spacecraft launched in 2011
Satellites using the SSL 1300 bus | Telstar 14R | Astronomy | 308 |
77,055,876 | https://en.wikipedia.org/wiki/Paloma%20Merodio%20G%C3%B3mez | Paloma Merodio Gómez (Mexico City, April 10, 1985) is a Mexican official and economist. She is a member of the Board of Governors of the National Institute of Statistics and Geography in Mexico, serving as Vice President responsible for the National Subsystem of Geographic, Environment, Land, and Urban Planning Information (SNIGMAOTU) from 2017 to 2024. She was chair of the United Nations Regional Committee on Global Geospatial Information Management for the Americas (UN-GGIM: Americas) from 2017 to 2021. From 2021 to 2024, she co-chaired the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM) one of the subsidiary bodies of the United Nations Economic and Social Council (ECOSOC) that fosters global development through geospatial information management.
Biography
Academic background
Born in Mexico City on April 10, 1985. She studied for a Bachelor's degree in Economics with a specialization in Political Economy at the Autonomous Technological Institute of Mexico from 2005 to 2009. After graduating, she pursued a Master's in Public Administration in International Development at Harvard University from 2011 to 2013. Subsequently, in 2024, she graduated with honors with a PhD in Economics from the National Autonomous University of Mexico.
Professional career
She worked at the Ministry of Social Development as the General Director of Evaluation and Monitoring of Social Programs and served at the Mexican Social Security Institute (IMSS) as the Coordinator of Strategic Research. She has been a consultant for the World Bank in Indonesia and for the International Finance Corporation (IFC).
In April 2017, she joined the Board of Governors of the National Institute of Statistics and Geography (INEGI) as the Vice President responsible for the National Subsystem of Geographic, Environmental, Land, and Urban Planning Information (SNIGMAOTU), which is part of the National System of Statistical and Geographic Information (SNIEG) of Mexico. With her appointment in 2017, she became the second woman to be part of the Board of Governors in the 34-year history of the Institute, following economist Rocío Ruiz Chávez in 2009. INEGI is the autonomous public body responsible for regulating and coordinating the National System of Statistical and Geographical Information. It is also tasked with collecting and disseminating information about Mexico in terms of territory, resources, population, and economy. This allows for understanding the characteristics of the country and aids in the decision-making process.
In December 2017, in her role as vice president, she assumed the presidency of the United Nations Regional Committee on Global Geospatial Information Management for the Americas (UN-GGIM: Americas) for a five-year term. During the eleventh session of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM), held in August 2021 at the United Nations headquarters in New York, she was elected Co-Chair of this committee alongside Ingrid Vanden Berghe of the National Geographic Institute of Belgium and Fernand Eanes Bale of the National Office of Technical Studies and Development in Ivory Coast.
She has been a member of the International Women's Forum, Mexico (IWF) since 2021. This forum seeks to strengthen a network of support by amplifying the voices and stories of its members, increasing presence and support with leadership and equality, and creating visibility.
Publications
Book
"Women in Statistics and in Geography" was presented on September 6, 2023, at the XXIV International Meeting on Gender Statistics held at the INEGI headquarters in Aguascalientes, Mexico. This book collects the life experiences and contributions of women who have advanced statistics and geography over four decades at the National Institute of Statistics and Geography in Mexico.
Selected publications
Arce Peña, N., Warman Diamant, J., Merodio Gómez, P., Aguilar López, J., Ramírez Santiago, A., Rhodes Espinoza, A., Hernández López, S., Rodríguez Ortega, C., Martí Flores, E., Izábal Martínez, J., Navarrete Hernández, A. & Jiménez Nava, F. (2022). Perspectivas para la integración de información oceánica en México.
Casanova, R., Merodio Gómez, P., Monett Hernández, A. & Ramírez Santiago, A. (2021). Americas' Geospatial Response to COVID-19. In Rajabifard et al., (Eds.), COVID-19 Pandemic, Geospatial Information, and Community Resilience: Global Applications and Lessons (pp. 245-254).
Céline, J., Merodio Gómez, P., Arriaga, V. & Ramírez Santiago, A. (2023). Citizen science interactions with official geospatial information: Case studies from Mexico. Frontiers in Environmental Science, 10, 01-17.
Dhu, T., Giuliani, G., Juárez, J., Kavvada, A., Killough, B., Merodio Gómez, P., Minchin, S. & Ramage, S. (2019). National Open Data Cubes and Their Contribution to Country-Level Development Policies and Practices. Data, 4(4), 1-17.
Juárez Carrillo, O. J., Merodio Gómez, P., Ponce Medina, M. S., Ornelas de Anda, J. L. & Coronado Iruegas, A. A. (2020). Cubo de datos geoespaciales para el uso de las imágenes satelitales en la generación de información geográfica y estadística. REALIDAD, DATOS Y ESPACIO: REVISTA INTERNACIONAL DE ESTADÍSTICA Y GEOGRAFÍA, 11(3), 124-139.
Kavvada, A., Ishida, C., Juárez Carrillo, J. O., Ramage, S., Merodio Gómez, P. & Friedl, L. (2022). EO4SDG. In Kavvada, A., et al., (Eds.), Earth Observation Applications and Global Policy Frameworks (pp. 145-157). American Geophysical Union.
Merodio Gómez, P., Pérez García, M., García Seco, G., Ramírez Santiago, A. & Tapia Johnson, C. (2019). The Americas' Spatial Data Infrastructure. ISPRS International Journal of Geo-Information, 8(10), 432.
Merodio Gómez, P., Juárez Carrillo, O. J., Kuffer, M., Thomson, D., Quiroz, J., Villaseñor García, E., Vanhuysse, S., Abascal, A., Oluoch, I., Nagenborg, M. & Persello, C. (2021). Earth Observations and Statistics: Unlocking Sociodemographic Knowledge through the Power of Satellite Images. Sustainability, 13, 12640.
Merodio Gómez, P., Limones García, E. & Ramírez Santiago, A. (2020). Strengthening resilience in the Caribbean region through the Spatial Data Infrastructures. International Journal of Cartography, 7(1), 60-77.
Merodio Gómez, P., Ramírez Santiago, A., García Seco, G., Casanova, R., MacKenzie, D. & Tucker, C. (2022). Ethics in the use of geospatial information in the Americas. Technology in Society, 69, 101964.
Merodio Gómez, P., Ramírez Santiago, A., García Seco, G., Moreno Mayorga, S. L. & Arias Vizcaino, L. A. (2023). Índice de Vulnerabilidad a COVID-19 en Centroamérica. Revista Geográfica, 166, 25–52.
Honors and awards
Recognized as a leader in the Geospatial World 50 Rising Stars 2021 initiative for her contributions as a proactive and passionate young professional valuing geospatial technology for society, the environment, and the economy.
Graduated with honors as Doctor of Economics from the National Autonomous University of Mexico in 2024.
Received a special mention for her Bachelor's degree in Economics in 2009.
References
External links
BIO Paloma Merodio Gómez
Paloma Merodio on LinkedIn
Geographic coordinate systems
1985 births
Living people
Harvard Kennedy School alumni
National Autonomous University of Mexico alumni
Mexican economists
United Nations Economic and Social Council | Paloma Merodio Gómez | Mathematics | 1,805 |
365,775 | https://en.wikipedia.org/wiki/Travel%20survey | A travel survey (or travel diary or travel behavior inventory) is a survey of individual travel behavior. Most surveys collect information about an individual (socio-economic, demographic, etc.), their household (size, structure, relationships), and a diary of their journeys on a given day (their start and end location, start and end time, mode of travel, accompaniment and purpose of travel).
Major travel surveys are conducted in metropolitan areas typically once a decade. Some regions, notably metropolitan Seattle, Washington conduct a panel survey, which interviews the same people year after year, to see how their particular behavior evolves over time.
Recent or continuous city-wide travel surveys
Auckland, New Zealand - A travel survey was conducted in 2006 and involved 6,000 households in the greater Auckland region.
Brisbane, Australia - The South East Queensland Travel Survey collects travel data in the Greater Brisbane region and the neighbouring areas of Gold Coast and Sunshine Coast. The continuous survey commenced in 2003 and surveys around 6,000 households every two years.
Hobart, Australia - The Greater Hobart Household Travel Survey collects information from 200 households each month.
London, United Kingdom - The London Travel Demand Survey covers 8,000 households annually. Data is collected via face to face interviews.
Sydney, Australia - The continuous Household Travel Survey collects travel data annually for approximately 3,500 households in the Sydney Greater Metropolitan Region.
Washington, United States - The Metropolitan Washington Council of Governments conducted a 10,000 household survey in 2007.
Recent or continuous regional travel surveys
Greater Golden Horseshoe, Canada - the Transportation Tomorrow Survey (TTS) has been conducted every five years since 1986, surveying approximately 5% of households across the region. The 2016 TTS is one of the largest and most comprehensive travel surveys in North America, comprising a dataset of 162,708 surveys conducted online and by phone.
Recent or continuous country-wide travel surveys
Denmark's most recent National Travel was initiated in 2006 and has been going on continuously since then. The interviews are conducted using the internet and telephone interviews.
Germany is conducting its National Travel Survey since 1994 on a yearly basis. Each household member fills in a travel diary in which he records each trip made during the course of one week. Despite this yearly survey there is another non regular scheduled survey which is conducted again in 2008. 25,000 households are expected to participate.
The Netherlands National Travel Survey surveyed around 34,500 households in 2003. The survey has been conducted yearly since 1985, but with some changes in methodology. Survey forms are mailed out, with follow-up motivational phone calls.
In New Zealand the Ministry of Transport annually surveys 4,600 households for a two-day period. Data is collected via face to face interviews.
The United Kingdom Department for Transport conducts the National Travel Survey
The United States last conducted the National Household Travel Survey in 2017.
South Africa conducted its first National Household Travel Survey in 2003. Successful interviews were held with 45,000 households.
Sweden's most recent National Travel Survey (RES) was conducted in 2006-06.
See also
Travel behavior
Transportation planning
Metropolitan Travel Survey Archive
NREL
Notes and references
External links
Metropolitan Travel Survey Archive
Household Travel Surveys on the WWW
Travel Survey Manual online
Transportation planning
Market research
Travel
Surveys (human research) | Travel survey | Physics | 653 |
4,459,459 | https://en.wikipedia.org/wiki/Soap%20dispenser | A soap dispenser is a device that, when manipulated or triggered appropriately, dispenses soap (usually in small, single-use quantities). They can be automatic or manually operated by a handle and are often found in public toilets or private bathrooms.
Manual
The design of a manual soap dispenser is generally determined by whether the soap comes in liquid, powder or foam form.
Liquid soap
When soap is dispensed in liquid form, it is generally in a squeeze bottle or pump. The most popular soap dispensers of this type are plastic pump bottles, many of which are disposable.
William Quick patented liquid soap on August 22, 1865. Minnetonka Corporation introduced the first modern liquid soap in 1980 and bought up the entire supply of plastic pumps used in their dispensers to delay competition entering the market.
Parts
Actuator – This is the top of the pump from which is pressed down to get the liquid out
Closure – Closure is the bottle that is fastened to the bottle's neck. it has a smooth or ribbed surface
Outer gasket – Made up of plastic or rubber, it is fit inside the closure and prevents leakage
Housing – The main pump that keeps the other components in the right place and sends liquid to the actuator from the dip tube
Dip tube – This is the visible tube that carries liquid from the bottom of the bottle up to the housing
Interior components – A spring, ball, piston or stem that helps move the liquid to the actuator
Operation
The handwash bottle acts much like an air suction device that draws liquid upwards to the user’s hands against the force of gravity. When the user presses down the actuator, the piston compresses the spring and upward air pressure pulls the ball upward, along with the liquid product into the dip tube and then reaches the housing. When the user releases the actuator, the spring returns the piston and actuator to the normal position and the ball returns to its earlier position to stop the backflow of the liquid back to the bottle. This process is called ‘priming' and is only used when the handwash is put in the bottle.
When the user presses the bottle again, the liquid in the housing is drawn from there and is released out of the actuator. The housing is again filled up with the handwash from the bottle, and the process goes on.
Dry soap
Some soap dispensers grate, plane or grind solid soap bars to flakes or powder as they are dispensed. About fresh weight of soap is equivalent to of liquid soap, providing soap for up to 400 handwashings.
Soap mills are common in public washrooms in Germany. Soap graters made specifically for home use can be wall-mounted or free-standing (like a pepper grinder) and waterproof for use in a shower. Some graters take specially-dimensioned soap bars, others will take a range of ordinary soap bar sizes.
Dispensers of pre-powdered soaps, such as borax, often take the form of a metal box with a weighted lever; when the lever is pressed, a handful of soap is released. Ground soap is also used to wash laundry.
Foam soap
Foam soap dispensers have dual foam pumps that when used, move both air and soap, injecting both together through small openings to create a lather. They can be found in both manual and automatic varieties.
Manual dispensers of foam soap often consist of a large button that squeezes the foam out of a tube. Many liquid soap dispensers operate in this way as well. A few dispensers operate with a lever that pulls forward and squeezes the soap out.
The majority of manual foam soap dispensers have the soap in a bladder in the dispenser in liquid form, as the pump is pressed the liquid soap is pushed through a small foaming nozzle which foams the soap.
Automatic
An automatic soap dispenser is specifically a hands-free dispenser of liquid or foam soap, and generally can be used for other liquids such as hand sanitizers, shampoos or hand lotions. They are often battery-powered-powered. Hands-free dispensers for water and soap/hand sanitizer have particular virtues for operating theatres and treatment rooms.
Mechanism
The touch-free design dispenses the liquid when a sensor detects motion under the nozzle. The electronic components of an automatic soap dispenser allow for a timing device or signal (sound, lights, etc.) which can indicate to the user whether they have washed their hands for the correct amount of time or not.
See also
Foam pump
Hand washing
Soapdish
References
Kitchenware
Bathroom equipment
Toilets
dispenser
Dispensers
Detergents | Soap dispenser | Chemistry,Technology,Biology | 1,001 |
12,421,756 | https://en.wikipedia.org/wiki/Percentage%20depth%20dose%20curve | In radiotherapy, a percentage depth dose curve (PDD) (sometimes percent depth dose curve) relates the absorbed dose deposited by a radiation beam into a medium as it varies with depth along the axis of the beam. The dose values are divided by the maximum dose, referred to as dmax, yielding a plot in terms of percentage of the maximum dose. Dose measurements are generally made in water or "water equivalent" plastic with an ionization chamber, since water is very similar to human tissue with regard to radiation scattering and absorption.
Percent depth dose (PDD), which reflects the overall percentage of dose deposited as compared to the depth of maximum dose, depends on the depth of interest, beam energy, field size, and SSD (source to surface distance) as follows. Of note, PDD generally refers to depths greater than the depth of maximum dose
PDD decreases with increasing depth due to the inverse square law and due to attenuation of the radiation beam
PDD increases with increasing radiation field size due to greater primary and scattered photons from the irradiated medium
PDD increases with increasing SSD because inverse square variations over a fixed distance interval are smaller at large total distance than small total distance
See also
Dosimetry
Dose profile
References
[1] Radiation Therapy Physics, Hendee W., Ibbott G. and Hendee E. (2005) Wiley-Liss Publ.,
Radiation therapy
Medical physics | Percentage depth dose curve | Physics | 290 |
11,225,114 | https://en.wikipedia.org/wiki/7-Aminoactinomycin%20D | 7-Aminoactinomycin D (7-AAD) is a fluorescent chemical compound with a strong affinity for DNA. It is used as a fluorescent marker for DNA in fluorescence microscopy and flow cytometry. It intercalates in double-stranded DNA, with a high affinity for GC-rich regions, making it useful for chromosome banding studies.
Applications
With an absorption maximum at 546 nm, 7-AAD is efficiently excited using a 543 nm helium–neon laser; it can also be excited with somewhat lower efficiency using a 488 nm or 514 nm argon laser lines. Its emission has a very large Stokes shift with a maximum in the deep red: 647 nm. 7-AAD is therefore compatible with most blue and green fluorophores – and even many red fluorophores – in multicolour applications.
7-AAD does not readily pass through intact cell membranes; if it is to be used as a stain for imaging DNA fluorescence, the cell membrane must be permeabilized or disrupted. This method can be used in combination with formaldehyde fixation of samples.
7-AAD is also used as a cell viability stain. Cells with compromised membranes will stain with 7-AAD, while live cells with intact cell membranes will remain dark. Viability of the cells in flow cytometry should be around 95% but not less than 90%.
Actinomycin D
The related compound actinomycin D is nonfluorescent, but binds DNA in the same way as 7-AAD. Its absorbance changes when bound to DNA, and it can be used as a stain in conventional transmission microscopy.
References
Gallery
External links
Structure from Invitrogen
MSDS
Fluorescent dyes
Cell imaging
Staining dyes
Cell biology
DNA intercalaters | 7-Aminoactinomycin D | Chemistry,Biology | 378 |
1,884,272 | https://en.wikipedia.org/wiki/Acyloin%20condensation | Acyloin condensation is a reductive coupling of two carboxylic esters using impure metallic sodium to yield an α-hydroxyketone, also known as an acyloin.
The reaction is most successful when R is aliphatic and saturated, and typically performed with a silyl chloride reactant to trap the product as a disilyl enediol ether.
The reaction is performed in aprotic solvents with a high boiling point, such as benzene and toluene, in an oxygen-free atmosphere (as even traces of oxygen interfere with the reaction path and reduce the yield). Protic solvents effect the Bouveault-Blanc ester reduction rather than condensation.
Independent of dilution, acyloin condensation of a diester favours intramolecular cyclisation (for all but the smallest rings) over intermolecular polymerisation. This effect is believed to originate in weak adsorption of the ester terminals at nearby sites on the sodium metal.
Acyloin cyclization of diesters
Intramolecular acyloin condensation is a classical approach for aliphatic ring synthesis, and "one of the best ways of closing rings of 10 members or more". 3-membered rings are not accessible through the acyloin condensation, 5- and 6-membered rings form in high yield (80 – 85% yield), 4-, 7-, 10-, and 11-membered rings form in moderate yield (50 – 60% yield), 8- and 9-membered rings form in poor to modest yield (30 – 40% yield), and finally, 12-membered and higher rings form in good to excellent yields (>70% yield). For larger rings, unsaturation does not inhibit cyclization. Although yields for 4-membered and medium-sized rings are poor to moderate, the acyloin condensation constitutes one of the earliest practical cyclization reactions to prepare these challenging ring sizes.
Tropolone is prepared via an initial acyloin condensation that delivers 2-hydroxycycloheptanone:
The dimethyl ester of sebacic acid can be converted to cyclodecanediol by acyloin condensation followed by hydrogenation using a copper chromite catalyst.
Comparison with other ring syntheses
The Dieckmann method is practical only for 5- to 8-membered rings (with modest yields for 7- and 8-membered). The Thorpe method is more easily modified via high dilution (e.g., 0.001 M in benzene/ether) to enable the synthesis of large rings, but 4-membered and 9- to 13-membered rings are still not accessible. Concentration is much less important a factor for obtaining high yields for the acyloin condensation, as the reaction occurs on the surface of the sodium metal. Although, the need for sodium metal limits the functional group tolerance of the reaction, compared to more modern cyclization reactions (e.g. Yamaguchi esterification, ring-closing olefin metathesis), the acyloin condensation continues to be used in the synthesis of complex natural products for the preparation of challenging ring systems.
Mechanism
The mechanism consists of four steps:
Oxidative ionization of two sodium atoms on the double bond of two ester molecules.
Wurtz-type coupling between two molecules of the homolytic ester derivative. Alkoxy-eliminations in both sides occur, producing a 1,2-diketone.
Oxidative ionization of two sodium atoms on both diketone double bonds. The sodium enediolate is formed.
Neutralization with water to form the enediol, which tautomerizes to acyloin.
Additives
The intermediate enediolate dianion can be trapped with trimethylsilyl chloride.
The reaction also produces stoichiometric quantities of alkoxide base, which can catalyze the competing Dieckmann condensation. 's technique traps the alkoxide and the acyloin with trimethylchlorosilane for considerably improved yields. The disilyl diether can then be cloven with acidified water or methanol.
In general, highly pure sodium can result in lower yields. The reaction is proposed to be influenced by an potassium impurity, which served as a catalyst. Sodium–potassium alloy is a viable reductant.
Usually toluene, dioxane, tetrahydrofuran or acyclic dialkylethers are employed as solvents. Advantageously also N-methyl-morpholine has been used. It allowed in some cases a successful reaction, where an otherwise-insoluble product coated the sodium sand, inhibiting the reaction.
See also
Benzoin condensation
Bouveault–Blanc reduction
Claisen condensation
Dieckmann condensation
References
External links
An animation of the mechanism
Condensation reactions
Organic redox reactions
Carbon-carbon bond forming reactions | Acyloin condensation | Chemistry | 1,061 |
51,695,411 | https://en.wikipedia.org/wiki/Permanent%20magnet%20motor | A permanent magnet motor is a type of electric motor that uses permanent magnets for the field excitation and a wound armature. The permanent magnets can either be stationary or rotating; interior or exterior to the armature for a radial flux machine or layered with the armature for an axial flux topology. The schematic shows a permanent magnet motor with stationary magnets outside of a brushed armature (a type commonly used on toy slot-cars).
Applications
Electric vehicles
This type of motor is used in GM's Chevrolet Bolt and Volt, and the rear wheel drive of Tesla's Model 3. Recent dual motor Tesla models use a combination of a permanent magnet motor at the back and traditional induction motor at the front.
Permanent magnet motors are more efficient than induction motor or motors with field windings for certain high-efficiency applications such as electric vehicles. Tesla's chief motor designer was quoted discussing these advantages, saying:
Types
Permanent magnet DC motors (powered by direct current)
Permanent-magnet synchronous motors (powered by alternating current)
Permanent magnet motors consist of two main types. Surface permanent magnet motors (SPM) and internal permanent magnet (IPM) motors. The main difference is that SPM motors place the magnets on the outside of the rotor while IPM motors place their magnets inside the motor. Benefits to internal magnets include structural integrity and reducing Back EMF. Since holes must be cut into the rotor for the placement of the magnets this creates areas of high reluctance allowing carmakers to obtain some of the benefits of reluctance motors as well as of permanent magnet motors.
Back electromotive force
Back electromotive force (EMF) is also known as the counter-electromotive force. It is the voltage that occurs in electric motors from the relative motion between the stator windings and the rotor’s magnetic field. The rotor's geometry determines the waveform's shape.
This effect is not unique to permanent magnet motors. Induction motors also suffer from it. However in an induction motor the fields from the rotor decrease as speed increases. A permanent magnet motor generates its own constant field. This means that as speed increases a voltage is induced linearly with the speed on the stator. This voltage is negative to the voltage provided to the motor and thus is a loss to the overall system.
Permanent magnetic motor materials
Many different permanent magnetic materials are used to drive permanent magnetic motors and vary based on multiple factors, principally necessary magnetic strength and cost. The four primary permanent magnetic materials that are found in the vast majority of industrial applications are neodymium iron boron (NdFeB), samarium cobalt (SmCo), aluminum nickel cobalt (Alnico), and strontium carbonate-iron oxide (also known as “ceramic magnet”); furthermore, significant materials science research is ongoing into the development of additional non-rare earth (NRE) permanent magnetic materials.
NdFeB Magnets
NdFeB is the strongest of all permanent magnet materials used in industrial applications and sees wide use in many types of permanent magnetic motors, including in disc drive spindle motors, electric vehicle motors, alternators, and sensors, power tools, electricity generators, and magnetic resonance imaging (MRI). NdFeB exhibits a Curie temperature of approximately 320 °C, which is significantly above room temperature, as well as very high remanence, coercivity, and energy product which allow it excellent performance in permanent magnetic applications. The most common method of NdFeB magnet production is sintering of alloyed neodymium, iron, and boron, typically in a nominal composition of approximately Nd14Fe78B8 (at%); sintering promotes growth of the Nd2Fe14B phase which is responsible for the characteristic strong magnetic behavior seen in NdFeB magnets. However, this also leads to corrosion vulnerability in NdFeB magnets along sintered grain boundaries, which requires alleviation through the addition of copper-nickel or aluminum-based metallic surface coatings. In addition, the high cost, rarity, and radioactive waste associated with production of the metal neodymium as an input means that NdFeB magnets are very financially and environmentally expensive.
SmCo Magnets
SmCo is a strong permanent magnetic material of comparable strength to NdFeB and is used across range of applications including very high-performance vehicle electric motors, NMR spectrometers, turbomachinery, and frictionless bearings. While NdFeB magnets exhibit a superior magnetic field, SmCo magnets have higher coercivity (i.e., less vulnerability to demagnetization) and better corrosion resistance. Furthermore, SmCo magnets have a Curie temperature exceeding 700 °C and superior temperature stability compared to NdFeB, making them more optimal for permanent magnetic motor applications involving high temperatures or cryogenic conditions. However, SmCo magnets contain a higher fraction of rare earth metals than NdFeB magnets, making them even more expensive and subject to the scarcity and environmental concerns of production; as such, SmCo magnets are now typically only used in specialty application cases where their particular temperature and coercivity advantages are significant.
Alnico Magnets
Alnico is a NRE permanent magnetic material used in permanent magnet motor applications such as magnetic speed and flow sensors, electric generators, and consumer goods. These magnets exhibit weaker performance in comparison to NdFeB and SmCo counterparts but still maintain high coercivity and are far cheaper due to their lack of rare earth metals. Furthermore, the high fraction of both aluminum and iron within these magnets lends them excellent corrosion resistance, electrical conductivity, and high-temperature stability; Alnico has one of the highest Curie temperatures of any known magnetic material at nearly 800°C. Despite this, Alnico’s comparatively low magnetic strength means it is one of the permanent magnets most susceptible to demagnetization, especially at cryogenic temperatures when constituent ferritic iron may transition to superconductivity.
Ceramic Magnets
Strontium carbonate and iron oxide, also known as a “ceramic” or “ferrite” magnet, is a NRE permanent magnetic material found in permanent magnet motor applications such as power tools, industrial magnetic separation processes, and automotive sensors. Ceramic magnets are significantly weaker than either SmCo or NdFeB but are generally stronger than Alnico magnets, in addition to being both more corrosion resistant and lower cost. However, ceramic magnets exhibit poorer temperature stability in comparison to Alnico and lose magnetization relatively easily when exposed to temperature extremes both hot and cold, with a much lower Curie temperature around 450 °C and a susceptibility to the same ferrite-driven demagnetization phenomena as Alnico under cryogenic conditions.
Emerging Permanent Magnetic Motor Materials
Development of non-rare earth, low cost, mechanically robust, and high strength permanent magnetic materials is a vigorous and ongoing area of research. Some notable materials systems of current interest include iron-cobalt-molybdenum ternary alloys, nanostructured cobalt-platinum alloys, and meteoric-type ordered iron-nickel alloys.
Environmental and supply concerns
Rare earth production has the consequence of generating waste with elevated radioactivity compared to the natural radioactivity of the ores (waste that is referred to by the US EPA as TENORM, or Technologically Enhanced Naturally Occurring Radioactive Materials). China, the top producer of neodymium, restricted shipments to Japan in 2010 during a controversy over disputed ownership of islands. China imposed strict export quotas on several rare earth metals, saying it wanted to control pollution and preserve resources. The quotas were lifted in 2015. Although neodymium is relatively abundant, global demand for neodymium outstripped production by about 10% in 2017.
See also
Induction motor
References
External links
Electric motors | Permanent magnet motor | Technology,Engineering | 1,613 |
266,145 | https://en.wikipedia.org/wiki/Schumann%20resonances | The Schumann resonances (SR) are a set of spectral peaks in the extremely low frequency portion of the Earth's electromagnetic field spectrum. Schumann resonances are global electromagnetic resonances, generated and excited by lightning discharges in the cavity formed by the Earth's surface and the ionosphere.
Description
The global electromagnetic resonance phenomenon is named after physicist Winfried Otto Schumann who predicted it mathematically in 1952.
Schumann resonances are the principal background in the part of the electromagnetic spectrum from 3 Hz through 60 Hz and appear as distinct peaks at extremely low frequencies around 7.83 Hz (fundamental), 14.3, 20.8, 27.3, and 33.8 Hz.
Schumann resonances occur because the space between the surface of the Earth and the conductive ionosphere acts as a closed, although variable-sized waveguide. The limited dimensions of the Earth cause this waveguide to act as a resonant cavity for electromagnetic waves in the extremely low frequency band. The cavity is naturally excited by electric currents in lightning.
In the normal mode descriptions of Schumann resonances, the fundamental mode is a standing wave in the Earth–ionosphere cavity with a wavelength equal to the circumference of the Earth. The lowest-frequency mode has the highest intensity, and the frequency of all modes can vary slightly owing to solar-induced perturbations to the ionosphere (which compress the upper wall of the closed cavity) amongst other factors. The higher resonance modes are spaced at approximately 6.5 Hz intervals (as may be seen by feeding numbers into the formula), a characteristic attributed to the atmosphere's spherical geometry. The peaks exhibit a spectral width of approximately 20% due to the damping of the respective modes in the dissipative cavity.
Observations of Schumann resonances have been used to track global lightning activity. Owing to the connection between lightning activity and the Earth's climate it has been suggested that they may be used to monitor global temperature variations and variations of water vapor in the upper troposphere. Schumann resonances have been used to study the lower ionosphere on Earth and it has been suggested as one way to explore the lower ionosphere on celestial bodies. Some have proposed that lightning on other planets might be detectable and studied by means of Schumann resonance signatures of those planets.
Effects on Schumann resonances have been reported following geomagnetic and ionospheric disturbances. More recently, discrete Schumann resonance excitation has been linked to transient luminous events — sprites, ELVES, jets, and other upper-atmospheric lightning. A new field of interest using Schumann resonances is related to short-term earthquake prediction.
Interest in Schumann resonances renewed in 1993 when E.R. Williams showed a correlation between the resonance frequency and tropical air temperatures, suggesting the resonance could be used to monitor global warming. In geophysical survey, Schumann resonances are used to locate offshore hydrocarbon deposits.
History
In 1893, George Francis FitzGerald noted that the upper layers of the atmosphere must be fairly good conductors. Assuming that the height of these layers is about 100 km above ground, he estimated that oscillations (in this case the lowest mode of the Schumann resonances) would have a period of 0.1 second. Because of this contribution, it has been suggested to rename these resonances "Schumann–FitzGerald resonances". However, FitzGerald's findings were not widely known, as they were only presented at a meeting of the British Association for the Advancement of Science, followed by a brief mention in a column in Nature.
The first suggestion that an ionosphere existed, capable of trapping electromagnetic waves, is attributed to Heaviside and Kennelly (1902). It took another twenty years before Edward Appleton and Barnett in 1925 were able to prove experimentally the existence of the ionosphere.
Although some of the most important mathematical tools for dealing with spherical waveguides were developed by G. N. Watson in 1918, it was Winfried Otto Schumann who first studied the theoretical aspects of the global resonances of the earth–ionosphere waveguide system, known today as the Schumann resonances. In 1952–1954 Schumann, together with H. L. König, attempted to measure the resonant frequencies. However, it was not until measurements made by Balser and Wagner in 1960–1963 that adequate analysis techniques were available to extract the resonance information from the background noise. Since then there has been an increasing interest in Schumann resonances in a wide variety of fields.
Basic theory
Lightning discharges are considered to be the primary natural source of Schumann resonance excitation; lightning channels behave like huge antennas that radiate electromagnetic energy at frequencies below about 100 kHz. These signals are very weak at large distances from the lightning source, but the Earth–ionosphere waveguide behaves like a resonator at extremely low resonance frequencies.
In an ideal cavity, the resonant frequency of the -th mode is determined by the Earth radius and the speed of light .
The real Earth–ionosphere waveguide is not a perfect electromagnetic resonant cavity. Losses due to finite ionosphere electrical conductivity lower the propagation speed of electromagnetic signals in the cavity, resulting in a resonance frequency that is lower than would be expected in an ideal case, and the observed peaks are wide. In addition, there are a number of horizontal asymmetries—day-night difference in the height of the ionosphere, latitudinal changes in the Earth's magnetic field, sudden ionospheric disturbances, polar cap absorption, variation in the Earth radius of ± 11 km from equator to geographic poles, etc. that produce other effects in the Schumann resonance power spectra.
Measurements
Today Schumann resonances are recorded at many separate research stations around the world. The sensors used to measure Schumann resonances typically consist of two horizontal magnetic inductive coils for measuring the north-south and east-west components of the magnetic field, and a vertical electric dipole antenna for measuring the vertical component of the electric field. A typical passband of the instruments is 3–100 Hz. The Schumann resonance electric field amplitude (~300 microvolts per meter) is much smaller than the static fair-weather electric field (~150 V/m) in the atmosphere.
Similarly, the amplitude of the Schumann resonance magnetic field (~1 picotesla) is many orders of magnitude smaller than the Earth's magnetic field (~30–50 microteslas). Specialized receivers and antennas are needed to detect and record Schumann resonances. The electric component is commonly measured with a ball antenna, suggested by Ogawa et al., in 1966, connected to a high-impedance amplifier. The magnetic induction coils typically consist of tens- to hundreds-of-thousands of turns of wire wound around a core of very high magnetic permeability.
Dependence on global lightning activity
From the very beginning of Schumann resonance studies, it was known that they could be used to monitor global lightning activity. At any given time there are about 2000 thunderstorms around the globe. Producing approximately 50 lightning events per second, these thunderstorms are directly linked to the background Schumann resonance signal.
Determining the spatial lightning distribution from Schumann resonance records is a complex problem. To estimate the lightning intensity from Schumann resonance records it is necessary to account for both the distance to lightning sources and the wave propagation between the source and the observer. A common approach is to make a preliminary assumption on the spatial lightning distribution, based on the known properties of lightning climatology. An alternative approach is placing the receiver at the North or South Pole, which remain approximately equidistant from the main thunderstorm centers during the day.
One method not requiring preliminary assumptions on the lightning distribution is based on the decomposition of the average background Schumann resonance spectra, utilizing ratios between the average electric and magnetic spectra and between their linear combination. This technique assumes the cavity is spherically symmetric and therefore does not include known cavity asymmetries that are believed to affect the resonance and propagation properties of electromagnetic waves in the system.
Diurnal variations
The best documented and the most debated features of the Schumann resonance phenomenon are the diurnal variations of the background Schumann resonance power spectrum.
A characteristic Schumann resonance diurnal record reflects the properties of both global lightning activity and the state of the Earth–ionosphere cavity between the source region and the observer. The vertical electric field is independent of the direction of the source relative to the observer, and is therefore a measure of global lightning.
The diurnal behavior of the vertical electric field shows three distinct maxima, associated with the three "hot spots" of planetary lightning activity: one at 9 UT (Universal Time) linked to the daily peak of thunderstorm activity from Southeast Asia; one at 14 UT linked to the peak of African lightning activity; and one at 20 UT linked to the peak of South American lightning activity. The time and amplitude of the peaks vary throughout the year, linked to seasonal changes in lightning activity.
"Chimney" ranking
In general, the African peak is the strongest, reflecting the major contribution of the African "chimney" to global lightning activity. The ranking of the two other peaks—Asian and American—is the subject of a vigorous dispute among Schumann resonance scientists. Schumann resonance observations made from Europe show a greater contribution from Asia than from South America, while observations made from North America indicate the dominant contribution comes from South America.
Williams and Sátori suggest that in order to obtain "correct" Asia-America chimney ranking, it is necessary to remove the influence of the day/night variations in the ionospheric conductivity (day-night asymmetry influence) from the Schumann resonance records. The "corrected" records presented in the work by Sátori, et al. show that even after the removal of the day-night asymmetry influence from Schumann resonance records, the Asian contribution remains greater than American.
Similar results were obtained by Pechony et al. who calculated Schumann resonance fields from satellite lightning data. It was assumed that the distribution of lightning in the satellite maps was a good proxy for Schumann excitations sources, even though satellite observations predominantly measure in-cloud lightning rather than the cloud-to-ground lightning that are the primary exciters of the resonances. Both simulations—those neglecting the day-night asymmetry, and those taking this asymmetry into account—showed the same Asia-America chimney ranking. On the other hand, some optical satellite and climatological lightning data suggest the South American thunderstorm center is stronger than the Asian center.
The reason for the disparity among rankings of Asian and American chimneys in Schumann resonance records remains unclear, and is the subject of further research.
Influence of the day-night asymmetry
In the early literature the observed diurnal variations of Schumann resonance power were explained by the variations in the source-receiver (lightning-observer) geometry. It was concluded that no particular systematic variations of the ionosphere (which serves as the upper waveguide boundary) are needed to explain these variations. Subsequent theoretical studies supported the early estimations of the small influence of the ionosphere day-night asymmetry (difference between day-side and night-side ionosphere conductivity) on the observed variations in Schumann resonance field intensities.
The interest in the influence of the day-night asymmetry in the ionosphere conductivity on Schumann resonances gained new strength in the 1990s, after publication of a work by Sentman and Fraser. developed a technique to separate the global and the local contributions to the observed field power variations using records obtained simultaneously at two stations that were widely separated in longitude. They interpreted the diurnal variations observed at each station in terms of a combination of a diurnally varying global excitation modulated by the local ionosphere height.
Their work, which combined both observations and energy conservation arguments, convinced many scientists of the importance of the ionospheric day-night asymmetry and inspired numerous experimental studies. Recently it was shown that results obtained by Sentman and Fraser can be approximately simulated with a uniform model (without taking into account ionosphere day-night variation) and therefore cannot be uniquely interpreted solely in terms of ionosphere height variation.
Schumann resonance amplitude records show significant diurnal and seasonal variations which generally coincide in time with the times of the day-night transition (the terminator). This time-matching seems to support the suggestion of a significant influence of the day-night ionosphere asymmetry on Schumann resonance amplitudes. There are records showing almost clock-like accuracy of the diurnal amplitude changes.
On the other hand, there are numerous days when Schumann resonance amplitudes do not increase at sunrise or do not decrease at sunset. There are studies showing that the general behavior of Schumann resonance amplitude records can be recreated from diurnal and seasonal thunderstorm migration, without invoking ionospheric variations. Two recent independent theoretical studies have shown that the variations in Schumann resonance power related to the day-night transition are much smaller than those associated with the peaks of the global lightning activity, and therefore the global lightning activity plays a more important role in the variation of the Schumann resonance power.
It is generally acknowledged that source-observer effects are the dominant source of the observed diurnal variations, but there remains considerable controversy about the degree to which day-night signatures are present in the data. Part of this controversy stems from the fact that the Schumann resonance parameters extractable from observations provide only a limited amount of information about the coupled lightning source-ionospheric system geometry. The problem of inverting observations to simultaneously infer both the lightning source function and ionospheric structure is therefore extremely underdetermined, leading to the possibility of non-unique interpretations.
"Inverse problem"
One of the interesting problems in Schumann resonances studies is determining the lightning source characteristics (the "inverse problem"). Temporally resolving each individual flash is impossible because the mean rate of excitation by lightning, ~50 lightning events per second globally, mixes up the individual contributions together. However, occasionally extremely large lightning flashes occur which produce distinctive signatures that stand out from the background signals. Called "Q-bursts", they are produced by intense lightning strikes that transfer large amounts of charge from clouds to the ground and often carry high peak current.
Q-bursts can exceed the amplitude of the background signal level by a factor of 10 or more and appear with intervals of ~10 s, which allows them to be considered as isolated events and determine the source lightning location. The source location is determined with either multi-station or single-station techniques and requires assuming a model for the Earth–ionosphere cavity. The multi-station techniques are more accurate, but require more complicated and expensive facilities.
Transient luminous events research
It is now believed that many of the Schumann resonances transients (Q bursts) are related to the transient luminous events (TLEs). In 1995, Boccippio et al. showed that sprites, the most common TLE, are produced by positive cloud-to-ground lightning occurring in the stratiform region of a thunderstorm system, and are accompanied by Q-burst in the Schumann resonances band. Recent observations reveal that occurrences of sprites and Q bursts are highly correlated and Schumann resonances data can possibly be used to estimate the global occurrence rate of sprites.
Global temperature
Williams [1992] suggested that global temperature may be monitored with the Schumann resonances. The link between Schumann resonance and temperature is lightning flash rate, which increases nonlinearly with temperature. The nonlinearity of the lightning-to-temperature relation provides a natural amplifier of the temperature changes and makes Schumann resonance a sensitive "thermometer". Moreover, the ice particles that are believed to participate in the electrification processes which result in a lightning discharge have an important role in the radiative feedback effects that influence the atmosphere temperature. Schumann resonances may therefore help us to understand these feedback effects. A paper was published in 2006 linking Schumann resonance to global surface temperature, which was followed up with a 2009 study.
Upper tropospheric water vapor
Tropospheric water vapor is a key element of the Earth's climate, which has direct effects as a greenhouse gas, as well as indirect effects through interaction with clouds, aerosols and tropospheric chemistry. Upper tropospheric water vapor (UTWV) has a much greater impact on the greenhouse effect than water vapor in the lower atmosphere, but whether this impact is a positive or a negative feedback is still uncertain.
The main challenge in addressing this question is the difficulty in monitoring UTWV globally over long timescales. Continental deep-convective thunderstorms produce most of the lightning discharges on Earth. In addition, they transport large amount of water vapor into the upper troposphere, dominating the variations of global UTWV. Price [2000] suggested that changes in the UTWV can be derived from records of Schumann resonances.
On other planets and moons
The existence of Schumann-like resonances is conditioned primarily by two factors:
A closed, planetary-sized and ellipsoidial cavity, consisting of conducting lower and upper boundaries separated by an insulating medium. For the earth the conducting lower boundary is its surface, and the upper boundary is the ionosphere. Other planets may have similar electrical conductivity geometry, so it is speculated that they should possess similar resonant behavior.
A source of electrical excitation of electromagnetic waves in the extremely low frequency range.
Within the Solar System there are five candidates for Schumann resonance detection besides the Earth: Venus, Mars, Jupiter, Saturn, and Saturn's biggest moon Titan.
Modeling Schumann resonances on the planets and moons of the Solar System is complicated by the lack of knowledge of the waveguide parameters. No in situ capability exists today to validate the results.
Venus
The strongest evidence for lightning on Venus comes from the electromagnetic waves first detected by Venera 11 and 12 landers. Theoretical calculations of the Schumann resonances at Venus were reported by Nickolaenko and Rabinowicz [1982] and Pechony and Price [2004]. Both studies yielded very close results, indicating that Schumann resonances should be easily detectable on that planet given a lightning source of excitation and a suitably located sensor.
Mars
In the case of Mars there have been terrestrial observations of radio emission spectra that have been associated with Schumann resonances. The reported radio emissions are not of the primary electromagnetic Schumann modes, but rather of secondary modulations of the nonthermal microwave emissions from the planet at approximately the expected Schumann frequencies, and have not been independently confirmed to be associated with lightning activity on Mars. There is the possibility that future lander missions could carry in situ instrumentation to perform the necessary measurements. Theoretical studies are primarily directed to parameterizing the problem for future planetary explorers.
Detection of lightning activity on Mars has been reported by Ruf et al. [2009]. The evidence is indirect and in the form of modulations of the nonthermal microwave spectrum at approximately the expected Schumann resonance frequencies. It has not been independently confirmed that these are associated with electrical discharges on Mars. In the event confirmation is made by direct, in situ observations, it would verify the suggestion of the possibility of charge separation and lightning strokes in the Martian dust storms made by Eden and Vonnegut [1973] and Renno et al. [2003].
Martian global resonances were modeled by Sukhorukov [1991], Pechony and Price [2004], and Molina-Cuberos et al. [2006]. The results of the three studies are somewhat different, but it seems that at least the first two Schumann resonance modes should be detectable. Evidence of the first three Schumann resonance modes is present in the spectra of radio emission from the lightning detected in Martian dust storms.
Titan
It was long ago suggested that lightning discharges may occur on Titan, but recent data from Cassini–Huygens seems to indicate that there is no lightning activity on this largest satellite of Saturn. Due to the recent interest in Titan, associated with the Cassini–Huygens mission, its ionosphere is perhaps the most thoroughly modeled today. Schumann resonances on Titan have received more attention than on any other celestial body, in works by Besser et al. [2002], Morente et al. [2003], Molina-Cuberos et al. [2004], Nickolaenko et al. [2003], and Pechony and Price [2004]. It appears that only the first Schumann resonance mode might be detectable on Titan.
Since the landing of the Huygens probe on Titan's surface in January 2005, there have been many reports on observations and theory of an atypical Schumann resonance on Titan. After several tens of fly-bys by Cassini, neither lightning nor thunderstorms were detected in Titan's atmosphere. Scientists therefore proposed another source of electrical excitation: induction of ionospheric currents by Saturn's co-rotating magnetosphere. All data and theoretical models comply with a Schumann resonance, the second eigenmode of which was observed by the Huygens probe. The most important result of this is the proof of existence of a buried liquid water-ammonia ocean under a few tens of km of the icy subsurface crust.
Jupiter and Saturn
Lightning activity has been optically detected on Jupiter. Existence of lightning activity on that planet was predicted by Bar-Nun [1975] and it is now supported by data from Galileo, Voyagers 1 and 2, Pioneers 10 and 11, and Cassini. Saturn is also confirmed to have lightning activity. Though three visiting spacecraft (Pioneer 11 in 1979, Voyager 1 in 1980, and Voyager 2 in 1981) failed to provide any convincing evidence from optical observations, in July 2012 the Cassini spacecraft detected visible lightning flashes, and electromagnetic sensors aboard the spacecraft detected signatures that are characteristic of lightning.
Little is known about the electrical parameters of the interior of Jupiter or Saturn. Even the question of what should serve as the lower waveguide boundary is a non-trivial one in case of the gaseous planets. There seem to be no works dedicated to Schumann resonances on Saturn. To date there has been only one attempt to model Schumann resonances on Jupiter.
Here, the electrical conductivity profile within the gaseous atmosphere of Jupiter was calculated using methods similar to those used to model stellar interiors, and it was pointed out that the same methods could be easily extended to the other gas giants Saturn, Uranus and Neptune. Given the intense lightning activity at Jupiter, the Schumann resonances should be easily detectable with a sensor suitably positioned within the planetary-ionospheric cavity.
See also
Cymatics
The Hum
Plasma (physics)
Radiant energy
Telluric current
Citations
External articles and references
General references
Articles on the NASA ADS Database: Full list | Full text
Sprite research video: The A.C. global circuit Schumann resonances oscillate at only eight cycles per second
Websites
"Construction and Deployment of an ULF Receiver for the Study of Schumann Resonance in Iowa" by Anton Kruger—Well illustrated study from the University of Iowa
Global Coherence Initiative (Spectrogram Calendar) Schumann resonance live data
Space Observing System Schumann resonance live data
The Discovery of Schumann Resonance
Animation
Schumann resonance animation from NASA Goddard Space Flight Center
Articles containing video clips
Atmospheric electricity
Electromagnetic radiation
Ionosphere | Schumann resonances | Physics | 4,757 |
68,517,181 | https://en.wikipedia.org/wiki/Accident%20Investigation%20Board%20%28Turkey%29 | Accident Investigation Board () was civil transportation accident investigation board of Turkey. The board established on May 6, 2013, and abolished on May 11, 2019. It was replaced by the Transport Safety Investigation Center. It was affiliated to the Ministry of Transport and Infrastructure.
References
External links
Government agencies of Turkey
Organizations investigating aviation accidents and incidents
Rail accident investigators
Transport organizations based in Turkey
Ministry of Transport and Infrastructure (Turkey)
Transport safety organizations | Accident Investigation Board (Turkey) | Technology | 86 |
658,208 | https://en.wikipedia.org/wiki/Cover%20date | The cover date of a periodical publication is the date displayed on the cover, which is not necessarily the true date of publication (the on-sale date or release date); later cover dates are common in magazine and comic book publishing. More unusually, Le Monde is a daily newspaper published the afternoon before its cover date. For some publications, the cover date may not be found on the cover, but rather on an inside jacket or on an interior page.
Magazines
In the United States, Canada, and the United Kingdom, the standard practice is to display on magazine covers a date which is some weeks or months in the future from the publishing or release date. There are two reasons for this discrepancy: first, to allow magazines to continue appearing "current" to consumers even after they have been on sale for some time (since not all magazines will be sold immediately), and second, to inform newsstands when an unsold magazine can be removed from the stands and returned to the publishing company or be destroyed (in this case, the cover date is also the pull date).
Weeklies (such as Time and Newsweek) are generally dated a week ahead. Monthlies (such as National Geographic) are generally dated two to three months ahead, and quarterlies are generally dated half a month ahead.
In other countries, the cover date usually matches more closely the date of publication, and may indeed be identical where weekly magazines are concerned.
In all markets, it is rare for monthly magazines to indicate a particular day of the month: thus issues are dated May 2016, and so on, whereas weekly magazines may be dated 17 May 2016.
Comic books
The general practice of most mainstream comic book companies since the creation of the comic book in the 1930s was to date individual issues by putting the name of a month (and much later the year as well) on the cover which was generally two months after the release date. For example, a 1951 issue of Superman which had the cover date of July would have been published two months earlier from that date in the month of May, generally speaking. In 1973 the discrepancy between the cover date and the publishing date went from two months to three months. In 1989 the cover date and publishing date discrepancy was changed back to two months, though generally each comic book company now uses its own system.
Of the two major American comic book publishers, DC Comics continues to put cover dates on the cover. Marvel Comics opted against putting cover dates on the cover in October 1999; instead, the "cover" date was moved to the indicia on an interior page.
References
Magazine publishing
Date and time representation
Comics terminology
Cover art | Cover date | Physics | 539 |
14,072,054 | https://en.wikipedia.org/wiki/WASP-3b | WASP-3b is an extrasolar planet orbiting the star WASP-3 located approximately 800 light-years away in the constellation Lyra. It was discovered via the transit method by SuperWASP, and follow up radial velocity observations confirmed that WASP-3b is a planet. The planet's mass and radius indicate that it is a gas giant with a similar bulk composition to Jupiter. WASP-3b has such an orbital distance around its star to classify it in the class of planets known as hot Jupiters and has an atmospheric temperature of approximately 1983 K.
WASP-3b undergoes no detectable gravitational tugging from other bodies in this system.
The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to 3.3°.
See also
Wide Angle Search for Planets
References
External links
WASP Planets
WASP-3 light curve using differential photometry
Exoplanets discovered by WASP
Exoplanets discovered in 2007
Giant planets
Hot Jupiters
Transiting exoplanets
Lyra | WASP-3b | Astronomy | 220 |
23,990,825 | https://en.wikipedia.org/wiki/Bromochlorofluoroiodomethane | Bromochlorofluoroiodomethane is a hypothetical haloalkane with all four stable halogen substituents present in it.
Overview
This compound can be seen as a methane molecule, whose four hydrogen atoms are each replaced with a different halogen atom. As the mirror images of this molecule are not superimposable, the molecule has two enantiomers. As one of the simplest such molecules, it is often cited as the prototypical chiral compound. However, since there is no synthetic route known to produce bromochlorofluoroiodomethane, the related simple chiral compound bromochlorofluoromethane is used instead when such a compound is required for research.
References
Halomethanes
Hypothetical chemical compounds
Chirality | Bromochlorofluoroiodomethane | Physics,Chemistry,Biology | 163 |
4,648,967 | https://en.wikipedia.org/wiki/Apollo%208%20Genesis%20reading | On Christmas Eve, December 24, 1968, the crew of Apollo 8, the first humans to travel to the Moon, read from the Book of Genesis during a television broadcast. During their ninth orbit of the Moon astronauts Bill Anders, Jim Lovell, and Frank Borman recited verses 1 through 10 of the Genesis creation narrative from the King James Bible. Anders read verses 1–4, Lovell verses 5–8, and Borman read verses 9 and 10.
Broadcast
Drafting, and Christina Laitin's suggestion to read from Genesis
Apollo 8 commander Frank Borman felt that his initial attempts to draft something appropriate to say on their Christmas Eve broadcast sounded too much like an apology for the United States involvement in the Vietnam War, and Joseph Laitin of the Bureau of the Budget (now the Office of Management and Budget) was brought in to assist. Laitin had the same problem; his initial drafts centered on the concept of peace on Earth, which felt inappropriate in light of the ongoing war effort. He began looking through the New Testament to find a good connection between the Christmas season and the biblical accounts of the birth of Jesus.
The suggestion to instead look to the Old Testament and use the beginning of Genesis came from Christine Laitin, Joseph Laitin's wife who, as a young teenager, was a member of the French Resistance during the occupation of Paris in World War II.
The Genesis text was printed on fire-proof paper and included in the mission flight plan.
Transcript
Bill Anders We are now approaching lunar sunrise, and for all the people back on Earth, the crew of Apollo 8 has a message that we would like to send to you.
In the beginning God created the heaven and the earth.And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.And God said, Let there be light: and there was light.And God saw the light, that it was good: and God divided the light from the darkness.
Jim Lovell
And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so.And God called the firmament Heaven. And the evening and the morning were the second day.
Frank Borman
And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so.And God called the dry land Earth; and the gathering together of the waters called he Seas: and God saw that it was good.
And from the crew of Apollo 8, we close with good night, good luck, a Merry Christmas – and God bless all of you, all of you on the good Earth.
Artifacts
The page of the flight plan with the Genesis passage is on display at the Adler Planetarium in Chicago, on loan from Lovell. In 2018 it was displayed in the National Cathedral in Washington, DC for the fiftieth anniversary of the flight.
Lawsuit
Madalyn Murray O'Hair, founder of American Atheists, responded by suing the United States government, alleging violations of the First Amendment. The suit was filed in the United States District Court for the Western District of Texas. It was submitted to a three-judge panel, which concluded that the case was not a three-judge matter, and dismissed the case for failure to state a cause of action. The direct appeal to the Supreme Court was dismissed for lack of jurisdiction. Another appeal was heard before the Fifth Circuit Court of Appeals, which affirmed the trial court's dismissal per curiam. The Supreme Court declined to review the case.
In popular culture
Postage stamp
In 1969, the United States Postal Service issued a postage stamp (Scott # 1371) to commemorate the Apollo 8 mission and the Genesis reading. The stamp includes the words "In the beginning God...", with the Apollo 8 Earthrise image in the background.
Art, entertainment, and media
Music and spoken word
Mike Oldfield used a part of the reading of Bill Anders in the first and second song of his 1994 album The Songs of Distant Earth.
The Israeli psychedelic trance group Astral Projection used a sample of the recording on their 1995 track "Let There Be Light".
Christian rock group Brave Saint Saturn sampled the recording in their song "Under Bridges", from the 2000 album So Far from Home.
The East-German alternative rock band Down Below samples the recording at the beginning of their song "How To Die In Space", from the 2004 album Silent Wings: Eternity.
Michael Jackson used the ending part of the Apollo 8 Genesis on his song "HIStory" from his album HIStory: Past, Present and Future, Book I (1995).
The group MGMT used the verses read by Borman as a sample in the song "Come On Christmas", from the 2005 album Climbing To New Lows.
The progressive rock band Arena used excerpts of this broadcast in the song "Purgatory Road" from the 2005 Pepper's Ghost album.
The Swedish progressive rock band Moon Safari used the first two sentences of Bill Anders' part on their song "Moonwalk".
The European electronic duo VNV Nation used a sample of the recording on "Genesis", a song from their 2002 album, Futureperfect.
The Dutch DJ Bakermat used the opening verse of the audio in his 2013 single "Uitzicht".
Electronic music duo W&W used an excerpt of Anders' verse in their 2013 song "Lift Off".
Television
In the 1995 Space: Above and Beyond episode "The River of Stars," the Apollo 8 recording is played for the 58th "Wildcards" Squadron.
The entire reading is reproduced verbatim in the "1968" episode of the 1998 HBO TV miniseries From the Earth to the Moon.
An excerpt from James Lovell's section of the reading was used in the 2017 episode "Freedom & Whisky" of the Starz series Outlander (season 3, episode 5).
Notes
External links
Genesis reading from Apollo 8
Apollo 8
Astronomical controversies
Book of Genesis
1968 in spaceflight
Christianity-related controversies
History of television
December 1968
Articles containing video clips
William Anders
Frank Borman
Jim Lovell
Genesis 1
Reading of religious texts
King James Version | Apollo 8 Genesis reading | Astronomy | 1,321 |
1,678,626 | https://en.wikipedia.org/wiki/Hyperfunction | In mathematics, hyperfunctions are generalizations of functions, as a 'jump' from one holomorphic function to another at a boundary, and can be thought of informally as distributions of infinite order. Hyperfunctions were introduced by Mikio Sato in 1958 in Japanese, (1959, 1960 in English), building upon earlier work by Laurent Schwartz, Grothendieck and others.
Formulation
A hyperfunction on the real line can be conceived of as the 'difference' between one holomorphic function defined on the upper half-plane and another on the lower half-plane. That is, a hyperfunction is specified by a pair (f, g), where f is a holomorphic function on the upper half-plane and g is a holomorphic function on the lower half-plane.
Informally, the hyperfunction is what the difference would be at the real line itself. This difference is not affected by adding the same holomorphic function to both f and g, so if h is a holomorphic function on the whole complex plane, the hyperfunctions (f, g) and (f + h, g + h) are defined to be equivalent.
Definition in one dimension
The motivation can be concretely implemented using ideas from sheaf cohomology. Let be the sheaf of holomorphic functions on Define the hyperfunctions on the real line as the first local cohomology group:
Concretely, let and be the upper half-plane and lower half-plane respectively. Then so
Since the zeroth cohomology group of any sheaf is simply the global sections of that sheaf, we see that a hyperfunction is a pair of holomorphic functions one each on the upper and lower complex halfplane modulo entire holomorphic functions.
More generally one can define for any open set as the quotient where is any open set with . One can show that this definition does not depend on the choice of giving another reason to think of hyperfunctions as "boundary values" of holomorphic functions.
Examples
If f is any holomorphic function on the whole complex plane, then the restriction of f to the real axis is a hyperfunction, represented by either (f, 0) or (0, −f).
The Heaviside step function can be represented as where is the principal value of the complex logarithm of .
The Dirac delta "function" is represented by This is really a restatement of Cauchy's integral formula. To verify it one can calculate the integration of f just below the real line, and subtract integration of g just above the real line - both from left to right. Note that the hyperfunction can be non-trivial, even if the components are analytic continuation of the same function. Also this can be easily checked by differentiating the Heaviside function.
If g is a continuous function (or more generally a distribution) on the real line with support contained in a bounded interval I, then g corresponds to the hyperfunction (f, −f), where f is a holomorphic function on the complement of I defined by This function f jumps in value by g(x) when crossing the real axis at the point x. The formula for f follows from the previous example by writing g as the convolution of itself with the Dirac delta function.
Using a partition of unity one can write any continuous function (distribution) as a locally finite sum of functions (distributions) with compact support. This can be exploited to extend the above embedding to an embedding
If f is any function that is holomorphic everywhere except for an essential singularity at 0 (for example, e1/z), then is a hyperfunction with support 0 that is not a distribution. If f has a pole of finite order at 0 then is a distribution, so when f has an essential singularity then looks like a "distribution of infinite order" at 0. (Note that distributions always have finite order at any point.)
Operations on hyperfunctions
Let be any open subset.
By definition is a vector space such that addition and multiplication with complex numbers are well-defined. Explicitly:
The obvious restriction maps turn into a sheaf (which is in fact flabby).
Multiplication with real analytic functions and differentiation are well-defined: With these definitions becomes a D-module and the embedding is a morphism of D-modules.
A point is called a holomorphic point of if restricts to a real analytic function in some small neighbourhood of If are two holomorphic points, then integration is well-defined: where are arbitrary curves with The integrals are independent of the choice of these curves because the upper and lower half plane are simply connected.
Let be the space of hyperfunctions with compact support. Via the bilinear form one associates to each hyperfunction with compact support a continuous linear function on This induces an identification of the dual space, with A special case worth considering is the case of continuous functions or distributions with compact support: If one considers (or ) as a subset of via the above embedding, then this computes exactly the traditional Lebesgue-integral. Furthermore: If is a distribution with compact support, is a real analytic function, and then Thus this notion of integration gives a precise meaning to formal expressions like which are undefined in the usual sense. Moreover: Because the real analytic functions are dense in is a subspace of . This is an alternative description of the same embedding .
If is a real analytic map between open sets of , then composition with is a well-defined operator from to :
See also
Algebraic analysis
Generalized function
Distribution (mathematics)
Microlocal analysis
Pseudo-differential operator
Sheaf cohomology
References
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External links
Algebraic analysis
Complex analysis
Generalized functions
Sheaf theory | Hyperfunction | Mathematics | 1,243 |
25,894,810 | https://en.wikipedia.org/wiki/Smoke%20damper | Smoke dampers are passive fire protection products used in air conditioning and ventilation ductwork or installed in physical smoke barriers (e.g., walls).
Use
Smoke damper may be used to prevent the spread of smoke from the space of fire origin to other spaces in the same building. A combination of fans and dampers can exhaust smoke from an area while pressurizing the smoke-free areas around the affected area (inhibiting smoke infiltration into additional areas). It may also be used to maintain the required concentration of a fire suppression clean agent in a space, as installed in supply air ducts to restrict the introduction of air into the space, and as installed in return or exhaust air ducts to restrict the depletion of the clean agent from the space. Smoke dampers are usually installed by sheet metal contractors.
Smoke dampers can be activated by the fire alarm system, usually initiated by smoke detectors, or interlocked with a fire suppression system. Smoke dampers close by an electric or pneumatic actuator, or a spring actuator, and can be either manually reset or driven open on a reset signal to the electric or pneumatic actuator.
Combination fire/smoke dampers are also available if a smoke barrier is desired at the same location as a fire barrier.
Fire dampers and smoke dampers are an integral and essential part of a building's passive fire protection system.
Inspection and maintenance
As with any other element of a building's passive fire protection system, smoke dampers need to be maintained, inspected and repaired to ensure they are in working order. The National Fire Protection Association (NFPA) requires the testing, maintenance and repair of smoke dampers as mandated in the Life Safety Code. NFPA 105 states [that] each damper shall be tested and inspected one year after installation. The test and inspection frequency shall then be every 4 years, except in hospitals, where the frequency shall be every 6 years. The code also states that the damper shall be actuated and cycled. The inspections must be document indicating the location of the damper, date of inspection, name of inspector, and deficiencies discovered.
As with fire damper inspections, smoke damper inspections are required by Authorities Having Jurisdiction (AHJ's). The International Code Council, the Joint Commission, NFPA and State Fire Marshals require these inspections as part of a Building's Life Safety Plan.
Repair
NFPA 105 requires that "if a damper is not operable, repairs shall begin as soon as possible". The repair of smoke dampers is more complicated as compared to fire dampers due to actuator replacement.
Certification
According to Underwriter's Laboratory, "smoke dampers certified by UL carry a leakage class rating that indicates the level of air leakage measured through the damper under test conditions."
References
External links
Underwriter's Laboratory Information on Smoke Dampers
Air Duct Cleaning Guide
Building engineering
Safety codes
Ventilation
Passive fire protection | Smoke damper | Engineering | 612 |
35,965,479 | https://en.wikipedia.org/wiki/Coercive%20citation | Coercive citation is an academic publishing practice in which an editor or referee of a scientific or academic journal forces an author to add spurious citations to an article before the journal will agree to publish it. This is done to inflate the journal's impact factor, thus artificially boosting the journal's scientific reputation. Manipulation of impact factors and self-citation has long been frowned upon in academic circles; however, the results of a 2012 survey indicate that about 20% of academics working in economics, sociology, psychology, and multiple business disciplines have experienced coercive citation. Individual cases have also been reported in other disciplines.
Background
The impact factor (IF) of a journal is a measure of how often, on average, papers published in the journal are cited in other academic publications. The IF was devised in the 1950s as a simple way to rank scientific journals. Today, in some disciplines, the prestige of a publication is determined largely by its impact factor.
Use of the impact factor is not necessarily undesirable as it can reasonably incentivise editors to improve their journal through the publication of good science. Two well-known academic journals, Nature and Science, had impact factors of 36 and 31 respectively. A respected journal in a sub-field, such as cognitive science, might have an impact factor of around 3.
However, impact factors have also become a source of increasing controversy. As early as 1999, in a landmark essay Scientific Communication – A Vanity Fair?, Georg Franck criticized citation counts as creating a marketplace where "success in science is rewarded with attention". In particular, he warned of a future "shadow market" where journal editors might inflate citation counts by requiring spurious references. In 2005, an article in The Chronicle of Higher Education called it "the number that's devouring science".
Definition
When an author submits a manuscript for publication in a scientific journal, the editor may request that the article's citations be expanded before it will be published. This is part of the standard peer review process and meant to improve the paper.
Coercive citation, on the other hand, is a specific unethical business practice in which the editor asks the author to add citations to papers published in the very same journal (self-citation) and in particular to cite papers that the author regards as duplicate or irrelevant. Specifically, the term refers to requests which:
Give no indication that the manuscript was lacking proper citations
Make no suggestion as to specific body of work requiring review
Direct authors to add citations only from the editor's own journal
In one incident, which has been cited as a particularly blatant example of coercive citation, a journal editor wrote: "you cite Leukemia [once in 42 references]. Consequently, we kindly ask you to add references of articles published in Leukemia to your present article".
Such a request would convey a clear message to authors: "add citations or risk rejection."
The effect of coercive citation is to artificially increase the journal's impact factor. Self-citation can have an appreciable effect: for example, in a published analysis, one journal's impact factor dropped from 2.731 to 0.748 when the self-citations were removed from consideration. It is important to note that not all self-citation is coercive, or indeed improper.
The practice of coercive citation is risky, as it may damage the reputation of the journal, and it hence has the potential of actually reducing the impact factor. Journals also risk temporary exclusion from Thomson Reuters' Journal Citation Reports, an influential list of impact factors, for such practices.
Practice
In 2012, Wilhite and Fong published results of a comprehensive survey of 6,700 scientists and academics in economics, sociology, psychology, and multiple business disciplines. In this survey, respondents were asked whether, when submitting a manuscript to a journal, they had ever been asked by the editor to include spurious citations to other papers in the same journal. Their findings indicate that 1 in 5 respondents have experienced coercive citation incidents, and that 86% regard it as unethical.
A number of factors related to coercive citation have been identified. Coercion is significantly more prevalent in some academic disciplines than others. Wilhite and Fong found that "journals in the business disciplines" (such as marketing, management, or finance) "coerce more than economics journals", whereas coercion in psychology and sociology is "no more prevalent, or even less prevalent" than it is in economics. However, despite the differences in prevalence, they noted that "every discipline" in their study "reported multiple instances of coercion" and that "there are published references to coercion in fields beyond the social sciences." The business journal industry has responded that they intend to confront the practice more directly.
Wilhite and Fong also found that characteristics of publishers are correlated with coercion. In their findings, "journals published by commercial, for-profit companies show significantly greater use of coercive tactics than journals from university presses", and journals published by academic societies also showed a higher likelihood of coercion than journals from university presses. Five of the top ten offenders identified in their research came from the same commercial publishing house, Elsevier.
There may also be a correlation between journal ranking and coercive citation. Some have suggested that larger and more highly ranked journals have more valuable reputations at stake, and thus may be more reluctant to jeopardize their reputations by using the practice. However, Wilhite and Fong found that:
Commonalities have also been identified among the targets of coercion. Coercive citation is primarily targeted at younger researchers with less senior academic ranks and at papers with a smaller number of authors in order to have the greatest effect on the impact factor. It was also found that authors from non-English-speaking countries were more likely to be targeted.
See also
Goodhart's law
References
See also
Citation cartel
External links
Phil Davis: "When Journal Editors Coerce Authors to Self-Cite". The Scholarly Kitchen 2 February 2012
Wilhite and Fong Supporting Data
Citation metrics
Coercion
Issues in ethics
Cheating in science
Research ethics | Coercive citation | Technology | 1,274 |
75,578,347 | https://en.wikipedia.org/wiki/AltStore | AltStore is an alternative app store for the iOS and iPadOS mobile operating systems, which allows users to download applications that are not available on the App Store, most commonly tweaked apps, jailbreak apps, and apps including paid apps on the app store. It was publicly announced on September 25, 2019, and launched on September 28.
History
Riley Testut is an American developer who began to work on AltStore after Apple declined to allow his Nintendo emulator Delta on the App Store. Since Xcode allowed him to temporarily install his Delta app to his iOS device for 7 days of testing, he created AltStore in 2019 to replicate this functionality, which could be extended to other .ipa files. As of 2022, AltStore had been downloaded 1.5 million times.
Features
AltStore exploits a loophole in the Xcode developer platform, which allows developers to sideload their own apps which they are working on without needing to jailbreak. Sideloaded apps are signed like a developer project for testing and will expire after 7 days with a free account or one year with a paid developer account, by which they will need to be refreshed or reinstalled.
References
Further reading
External links
Notes
1.AltStore PAL is only available on iPhone.
Application software
IOS software
Mobile software distribution platforms | AltStore | Technology | 271 |
14,110,027 | https://en.wikipedia.org/wiki/Metro%20Ring%20Protocol | The Metro Ring Protocol (MRP) is a Layer 2 resilience protocol developed by Foundry Networks and currently being delivered in products manufactured by Brocade Communications Systems and Hewlett Packard. The protocol quite tightly specifies a topology in which layer 2 devices, usually at the core of a larger network, are configured and as such is able to achieve much faster failover times than other Layer 2 protocols such as Spanning Tree.
See also
ITU-T G.8032 Ethernet Ring Protection Switching
EAPS, Ethernet Automatic Protection Switching
Internet protocols
Link protocols | Metro Ring Protocol | Technology | 111 |
33,815,651 | https://en.wikipedia.org/wiki/3%2C4-Dichloroamphetamine | 3,4-Dichloroamphetamine (3,4-DCA), is an amphetamine derived drug invented by Eli Lilly in the 1960s, which has a number of pharmacological actions. It acts as a highly potent and selective serotonin releasing agent (SSRA) and binds to the serotonin transporter with high affinity, but also acts as a selective serotonergic neurotoxin in a similar manner to the related para-chloroamphetamine (PCA), though with slightly lower potency. It is also a monoamine oxidase inhibitor (MAOI), as well as a very potent inhibitor of the enzyme phenylethanolamine N-methyl transferase which normally functions to transform noradrenaline into adrenaline in the body.
Chemistry
Synthesis
The reaction of 3,4-dichlorobenzyl chloride (1) with cyanide anion gives 3,4-dichlorophenylacetonitrile (2). Reaction with sodium methoxide and ethyl acetate gives α-acetoxy-3,4-dichlorophenylacetonitrile, (3). Removal of the nitrile group in the presence of sulfuric acid gives 3,4-dichlorophenylacetone (4). Oxime formation with hydroxylamine gives N-[1-(3,4-dichlorophenyl)propan-2-ylidene]hydroxylamine, (5). Reduction of the oxime completed the synthesis of 3,4-dichloroamphetamine (6).
See also
2,4-Dichloroamphetamine
3-Chloroamphetamine
3-Methoxy-4-methylamphetamine
Cericlamine
Chlorphentermine
Clortermine
Etolorex
3,4-Methylenedioxyamphetamine
para-Chloroamphetamine
para-Methoxyamphetamine
References
Abandoned drugs
Monoamine oxidase inhibitors
Monoaminergic neurotoxins
Serotonin-norepinephrine-dopamine releasing agents
Serotonin releasing agents
Substituted amphetamines | 3,4-Dichloroamphetamine | Chemistry | 472 |
8,969,762 | https://en.wikipedia.org/wiki/CWSDPMI | CWSDPMI is a 32-bit DPMI host written by Charles W. Sandmann from 1996 to 2010, currently at r7. It is loosely based upon prior GO32.EXE code used in DJGPP v1. It can provide DPMI 0.90+ 32-bit services for programs compiled with latest versions of DJGPP etc. compilers. Since r5, it can also be used for programs requiring a DPMI stub in lieu of PMODE/DJ. It supports up to 4 GB, virtual memory, and hardware interrupt reflection from real mode to protected mode. Programs compiled with DJGPP v2 require a DPMI host, which is usually CWSDPMI.EXE or CWSDPR0.EXE. In case of CWSDPMI.EXE, the default paging/virtual memory file is C:\CWSDPMI.SWP. It is capable of running on a 386 in under 512 KB of RAM.
CWSDPMI is functionally similar to other 32-bit DPMI hosts such as HDPMI32, which is part of HX DOS Extender.
CWSDPMI r7 is free and open-source software.
CWSDPMI editions
CWSDSTUB.EXE is a stub loader image for DJGPP which includes CWSDPMI.
CWSDPR0.EXE is an alternative version, implemented at request of id Software when writing Quake, which runs at ring 0 with virtual memory disabled. It may be used if access to ring 0 features are desired. It currently does not switch stacks on hardware interrupts, so some DJGPP features such as SIGINT and SIGFPE are not supported and will generate a double fault or stack fault error.
Developer Charles W. Sandmann also hoped to eventually supply code for CWSDPMI r7 that allows CWSDPMI to map up to 64 GB memory into the address space upon request.
See also
DOS extender
References
External links
Official CWSDPMI website
DOS extenders
DOS software
1996 software | CWSDPMI | Technology,Engineering | 432 |
8,591,843 | https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Sculptor | This is the list of notable stars in the constellation Sculptor, sorted by decreasing brightness.
See also
List of stars by constellation
References
List
Sculptor | List of stars in Sculptor | Astronomy | 29 |
2,588,077 | https://en.wikipedia.org/wiki/Handrail | A handrail is a rail that is designed to be grasped by the hand so as to provide safety or support. In Britain, handrails are referred to as banisters. Handrails are commonly used while ascending or descending stairways and escalators in order to prevent injurious falls, and to provide bodily support in bathrooms or similar areas. Handrails are typically supported by balusters or attached to walls.
Similar items not covered in this article include bathroom handrails—which help to prevent falls on slippery, wet floors—other grab bars, used, for instance, in ships' galleys, and barres, which serve as training aids for ballet dancers. Guard rails and balustrades line drop-offs and other dangerous areas, keeping people and vehicles out.
British specifications
British Standard and British Standard Code of Practice are harmonized to European Normal (EN) series. Handrail height is set between .
US specifications
Dimensions
Various model codes—The International Code Council (ICC) and National Fire Protection Association (NFPA)—and accessibility standards—ANSI A117.1 and the Americans With Disabilities Act Standards for Accessible Design (ADASAD)—refer to handrail dimensions. Current versions of these codes and standards now agree that handrail is defined as either a circular cross section with an outside diameter of minimum and maximum or a non-circular cross section with a perimeter dimension of minimum and maximum and a cross section dimension of ) maximum. In addition, the International Residential Code (IRC) includes a definition of a "Type II" handrail that allows for handrail with a perimeter dimension greater than .
The IRC and residential portion of the 2009 IBC define Type II handrail as follows:
Handrails are located at a height between . In areas where children are the principal users of a building or facility, the 2010 ADASAD recommends that a second set of handrails at a maximum height of measured to the top of the gripping surface from the ramp surface or stair nosing can assist in preventing accidents.
Clearance
The distance between the wall and handrail gripping surface is also governed by local code with the most common requirement being minimum. The National Fire Protection Agency (NFPA) and the Occupational Safety and Health Administration (OSHA) require that the distance between the wall and handrail be a minimum of .
The 1992 Americans With Disabilities Act Accessibility Guidelines (ADAAG) stated that there was to be an absolute dimension of between a handrail and a wall. This was actually a "grab bar" dimension which was part of the 1986 ANSI A117.1. ANSI changed the notation to minimum in 1990. This was not corrected in 2010 with the approval of the new ADASAD which now calls for a minimum clearance.
Codes also generally require that there be a clearance between the underside of the handrail and any obstruction—including the horizontal bracket arm. There is an allowance however for variations in the handrail size—for every of additional perimeter dimension over , may be subtracted from the clearance requirement.
Strength
Handrails are to support a continuous load of or a concentrated load of applied at the top of the handrail. As handrails come in different materials, the strengths can vary. From timber to stainless steel, it is best to pick a handrail that will be right for the area. Stainless steel will be stronger and more durable outside, whereas timber can be just as strong but less durable outside.
ADA height notations
ADA Handrail height requirements are issued to create a safe enjoyable space to enjoy for everyone. The ADA height of handrail requirements that will primarily be used by children have their own unique requirements.
The top of gripping surfaces of handrails shall be 34 inches minimum and 38 inches maximum vertically above walking surfaces, stair nosing, and ramp surfaces. Handrails shall be at a consistent height above walking surfaces, stair nosing, and ramp surfaces.
When children are the principal users in a building or facility (e.g., elementary schools), a second set of handrails at an appropriate height can assist them and aid in preventing accidents. A maximum height of 28 inches measured to the top of the gripping surface from the ramp surface or stair nosing. Sufficient vertical clearance between upper and lower handrails, 9 inches minimum, should be provided to help prevent entrapment.
Adult requirements
Top of gripping surfaces of handrails shall be between vertically above walking surfaces, stair nosings, and ramp surfaces. Handrails shall be at a consistent height above walking surfaces, stair nosings, and ramp surfaces.
Child recommendation
When children are the principal users in a building or facility (e.g., elementary schools), a second set of handrails at an appropriate height can assist them and aid in preventing accidents. A maximum height of measured to the top of the gripping surface from the ramp surface or stair nosing is recommended for handrails designed for children. Sufficient vertical clearance between upper and lower handrails, minimum, should be provided to help prevent entrapment.
Types of handrails
Handrails are available in several different varieties including wooden/timber, stainless steel, brass, or aluminium. Some varieties are more hard-wearing than others, and the cost can vary depending on the style you choose. You can also choose various fixings to allow for a more modern/sleek look.
See also
Baluster
Guard rail
Hanging strap
Mobile safety steps
Stanchion
References
External links
Architectural elements
Garden features
Ironmongery
Stairs
Stairways | Handrail | Technology,Engineering | 1,126 |
11,127,691 | https://en.wikipedia.org/wiki/Diaporthe%20perniciosa | Diaporthe perniciosa a species of fungus in the family Diaporthaceae. It is a plant pathogen.
The names Phoma prunorum Cooke, Phomopsis prunorum (Cooke) Grove, and Phomopsis mali Roberts have been used for its asexual (anamorph) form.
It causes bark cankers on trees in the genera Malus (apples), Pyrus (pears) and Prunus (plums, cherries, peaches and other similar fruits). It has also been implicated in dieback disease of plums. One study in the late 1980s was able to isolate the fungus from several trees with die-back symptoms but inoculation of healthy trees with the fungus did not result in disease.
References
perniciosa
Fungi described in 1921
Fungal plant pathogens and diseases
Fungus species | Diaporthe perniciosa | Biology | 177 |
31,033 | https://en.wikipedia.org/wiki/Great%20Molasses%20Flood | The Great Molasses Flood, also known as the Boston Molasses Disaster, was a disaster that occurred on Wednesday, January 15, 1919, in the North End neighborhood of Boston, Massachusetts.
A large storage tank filled with of molasses, weighing approximately burst, and the resultant wave of molasses rushed through the streets at an estimated , killing 21 people and injuring 150. The event entered local folklore and residents reported for decades afterwards that the area still smelled of molasses on hot summer days.
Flood
Molasses can be fermented to produce ethanol, the active ingredient in alcoholic beverages and a key component in munitions. The disaster occurred at the Purity Distilling Company facility at 529Commercial Street near Keany Square. A considerable amount of molasses had been stored there by the company, which used the harborside Commercial Street tank to offload molasses from ships and store it for later transfer by pipeline to the Purity ethanol plant situated between Willow Street and Evereteze Way in Cambridge, Massachusetts. The molasses tank stood tall and in diameter, and contained as much as .
On January 15, 1919, temperatures in Boston had risen above , climbing rapidly from the frigid temperatures of the preceding days, and the previous day, a ship had delivered a fresh load of molasses, which had been warmed to decrease its viscosity for transfer. Possibly due to the thermal expansion of the older, colder molasses already inside the tank, the tank burst open and collapsed at approximately 12:30p.m. Witnesses reported that they felt the ground shake and heard a roar as it collapsed, a long rumble similar to the passing of an elevated train; others reported a tremendous crashing, a deep growling, "a thunderclap-like ", and a sound like a machine gun as the rivets shot out of the tank.
The density of molasses is about , 40 percent more dense than water, resulting in the molasses having a great deal of potential energy. The collapse translated this energy into a wave of molasses high at its peak, moving at . The wave was of sufficient force to drive steel panels of the burst tank against the girders of the adjacent Boston Elevated Railway's Atlantic Avenue structure and tip a streetcar momentarily off the El's tracks. Stephen Puleo describes how nearby buildings were swept off their foundations and crushed. Several blocks were flooded to a depth of . Puleo quotes a Boston Post report:
The Boston Globe reported that people "were picked up by a rush of air and hurled many feet". Others had debris hurled at them from the rush of sweet-smelling air. A truck was picked up and hurled into Boston Harbor. After the initial wave, the molasses became viscous, exacerbated by the cold temperatures, trapping those caught in the wave and making it even more difficult to rescue them. About 150 people were injured, and 21 people and several horses were killed. Some were crushed and drowned by the molasses or by the debris that it carried within. The wounded included people, horses, and dogs; coughing fits became one of the most common ailments after the initial blast. Edwards Park wrote of one child's experience in a 1983 article for Smithsonian:
Aftermath
First to the scene were 116 cadets under the direction of Lieutenant Commander H. J. Copeland from , a training ship of the Massachusetts Nautical School (now the Massachusetts Maritime Academy) that was docked nearby at the playground pier. The cadets ran several blocks toward the accident and entered into the knee-deep flood of molasses to pull out the survivors, while others worked to keep curious onlookers from getting in the way of the rescuers. The Boston Police, Red Cross, Army, and Navy personnel soon arrived. Some nurses from the Red Cross dove into the molasses, while others tended to the injured, keeping them warm and feeding the exhausted workers. Many of these people worked through the night, and the injured were so numerous that doctors and surgeons set up a makeshift hospital in a nearby building. Rescuers found it difficult to make their way through the syrup to help the victims, and four days elapsed before they stopped searching; many of the dead were so glazed over in molasses that they were hard to recognize. Other victims were swept into Boston Harbor and were found three to four months after the disaster.
In the wake of the accident, 119 residents brought a class-action lawsuit against the United States Industrial Alcohol Company (USIA), which had bought Purity Distilling in 1917. It was one of the first class-action suits in Massachusetts and is considered a milestone in paving the way for modern corporate regulation. The company claimed that the tank had been blown up by anarchists because some of the alcohol produced was to be used in making munitions, but a court-appointed auditor found USIA responsible after three years of hearings, and the company ultimately paid out $628,000 in damages ($ in , adjusted for inflation). Relatives of those killed reportedly received around $7,000 per victim (equivalent to $ in ).
Cleanup
Cleanup crews used salt water from a fireboat to wash away the molasses and sand to absorb it, and the harbor was brown with molasses until summer. The cleanup in the immediate area took weeks, with several hundred people contributing to the effort, and it took longer to clean the rest of Greater Boston and its suburbs. Rescue workers, cleanup crews, and sight-seers had tracked molasses through the streets and spread it to subway platforms, to the seats inside trains and streetcars, to pay telephone handsets, into homes, and to countless other places. It was reported that "Everything that a Bostonian touched was sticky."
Fatalities
Causes
Several factors might have contributed to the disaster. The first factor is that the tank may have leaked from the very first day that it was filled in 1915. The tank was also constructed poorly and tested insufficiently, and carbon dioxide production might have raised the internal pressure due to fermentation in the tank. Warmer weather the previous day would have assisted in building this pressure, as the air temperature rose from over that period. The failure occurred from a manhole cover near the base of the tank, and a fatigue crack there possibly grew to the point of criticality.
The tank had been filled to capacity only eight times since it was built a few years previously, putting the walls under an intermittent, cyclical load. Several authors say that the Purity Distilling Company was trying to out-race prohibition, as the 18th amendment was ratified the next day (January 16, 1919) and took effect one year later. An inquiry after the disaster revealed that Arthur Jell, USIA's treasurer, neglected basic safety tests while overseeing construction of the tank, such as filling it with water insufficient to check for leaks, and ignored warning signs such as groaning noises each time the tank was filled. He had no architectural or engineering experience. When filled with molasses, the tank leaked so badly that it was painted brown to hide the leakage. Local residents collected leaked molasses for their homes. A 2014 investigation applied modern engineering analysis and found that the steel was half as thick as it should have been for a tank of its size even with the lower standards they had at the time. Another issue was that the steel lacked manganese and was made more brittle as a result. The tank's rivets were also apparently flawed, and cracks first formed at the rivet holes.
In 2016, a team of scientists and students at Harvard University conducted extensive studies of the disaster, gathering data from many sources, including 1919 newspaper articles, old maps, and weather reports. The student researchers also studied the behavior of cold corn syrup flooding a scale model of the affected neighborhood. The researchers concluded that the reports of the high speed of the flood were credible.
Two days before the disaster, warmer molasses had been added to the tank, reducing the viscosity of the fluid. When the tank collapsed, the fluid cooled quickly as it spread, until it reached Boston's winter evening temperatures and the viscosity increased dramatically. The Harvard study concluded that the molasses cooled and thickened quickly as it rushed through the streets, hampering efforts to free victims before they suffocated.
Area today
United States Industrial Alcohol did not rebuild the tank. The property formerly occupied by the molasses tank and the North End Paving Company became a yard for the Boston Elevated Railway (predecessor to the Massachusetts Bay Transportation Authority). It is now the site of a city-owned recreational complex, officially named Langone Park, featuring a Little League Baseball field, a playground, and bocce courts. Immediately to the east is the larger Puopolo Park, with additional recreational facilities.
A small plaque at the entrance to Puopolo Park, placed by the Bostonian Society, commemorates the disaster. The plaque, titled "Boston Molasses Flood", reads:
The accident has since become a staple of local culture, not only for the damage the flood brought, but also for the sweet smell that filled the North End for decades after the disaster. According to journalist Edwards Park, "The smell of molasses remained for decades a distinctive, unmistakable atmosphere of Boston."
On January 15, 2019, for the 100th anniversary of the event, a ceremony was held in remembrance. Ground-penetrating radar was used to identify the exact location of the tank from 1919. The concrete slab base for the tank remains in place approximately below the surface of the baseball diamond at Langone Park. Attendees of the ceremony stood in a circle marking the edge of the tank. The 21 names of those who died in, or as a result of, the flood were read aloud.
Many laws and regulations governing construction were changed as a direct result of the disaster, including requirements for oversight by a licensed architect and civil engineer.
In popular culture
The Darkest of the Hillside Thickets' song "Great Molasses Disaster" is about the flood, and their official music video includes many pictures of the aftermath.
Canadian metal band Protest The Hero's song "All Hands" from the album Palimpsest is written from the perspective of a victim of the flood. The piano interlude to the song is titled "Harborside" a reference to the harborside tanks in which the molasses was stored. The last lines of the song references the first hand accounts of the aftermath.
Comedian and actress Ayo Edebiri, on Late Night with Seth Meyers, passionately spoke about the Great Molasses Flood where she mentions that she was "reduced to tears" talking about the tragedy, where people outside of Boston are far less aware of the event.
See also
List of disasters in Massachusetts by death toll
List of non-water floods
Honolulu molasses spill
Notes
References
Further reading
External links
Boston Public Library. Photos related to the event on Flickr. Many phrases are direct quotes.
The Great Boston Molasses Flood of 1919, four-minute audio story at The American Storyteller Radio Journal
Interview with Stephen Puleo, author of the book listed in "Further reading"
Molasses Flood of 1919
"Scenes in the Molasses-Flooded Streets of Boston", from the Washington Times, January 18, 1919
100 years ago, Boston’s North End was hit by a deadly wave of molasses (photos)
The Great Molasses Flood of 1919 was Boston’s strangest disaster (story with more photos)
1910s in Boston
1919 disasters in the United States
1919 in Massachusetts
1919 industrial disasters
Cultural history of Boston
Disasters in Boston
Engineering failures
Environmental disasters in the United States
Floods in the United States
Food processing disasters
Industrial accidents and incidents in the United States
January 1919 events in the United States
Molasses
North End, Boston | Great Molasses Flood | Technology,Engineering | 2,411 |
14,703,145 | https://en.wikipedia.org/wiki/Aubin%E2%80%93Lions%20lemma | In mathematics, the Aubin–Lions lemma (or theorem) is the result in the theory of Sobolev spaces of Banach space-valued functions, which provides a compactness criterion that is useful in the study of nonlinear evolutionary partial differential equations. Typically, to prove the existence of solutions one first constructs approximate solutions (for example, by a Galerkin method or by mollification of the equation), then uses the compactness lemma to show that there is a convergent subsequence of approximate solutions whose limit is a solution.
The result is named after the French mathematicians Jean-Pierre Aubin and Jacques-Louis Lions. In the original proof by Aubin, the spaces X0 and X1 in the statement of the lemma were assumed to be reflexive, but this assumption was removed by Simon, so the result is also referred to as the Aubin–Lions–Simon lemma.
Statement of the lemma
Let X0, X and X1 be three Banach spaces with X0 ⊆ X ⊆ X1. Suppose that X0 is compactly embedded in X and that X is continuously embedded in X1. For , let
(i) If then the embedding of into is compact.
(ii) If and then the embedding of into is compact.
See also
Lions–Magenes lemma
Notes
References
(Theorem II.5.16)
(Sect.7.3)
(Proposition III.1.3)
Banach spaces
Theorems in functional analysis
Lemmas in analysis
Measure theory | Aubin–Lions lemma | Mathematics | 316 |
2,694,431 | https://en.wikipedia.org/wiki/Germanium%20tetrachloride | Germanium tetrachloride is a colourless, fuming liquid with a peculiar, acidic odour. It is used as an intermediate in the production of purified germanium metal. In recent years, GeCl4 usage has increased substantially due to its use as a reagent for fiber optic production.
Production
Most commercial production of germanium is from treating flue-dusts of zinc- and copper-ore smelters, although a significant source is also found in the ash from the combustion of certain types of coal called vitrain. Germanium tetrachloride is an intermediate for the purification of germanium metal or its oxide, GeO2.
Germanium tetrachloride can be generated directly from GeO2 (germanium dioxide) by dissolution of the oxide in concentrated hydrochloric acid. The resulting mixture is fractionally distilled to purify and separate the germanium tetrachloride from other products and impurities. The GeCl4 can be rehydrolysed with deionized water to produce pure GeO2, which is then reduced under hydrogen to produce germanium metal.
Production of GeO2, however, is dependent on the oxidized form of germanium extracted from the ore. Copper-lead-sulfide and zinc-sulfide ores will produce GeS2, which is subsequently oxidized to GeO2 with an oxidizer such as sodium chlorate. Zinc-ores are roasted and sintered and can produce the GeO2 directly. The oxide is then processed as discussed above.
The classic synthesis from chlorine and germanium metal at elevated temperatures is also possible. Additionally, a chlorine free activation of germanium has been developed, giving a less energy intensive and more environmentally friendly alternative synthesis for germanium precursors.
Application
Germanium tetrachloride is used almost exclusively as an intermediate for several optical processes. GeCl4 can be directly hydrolysed to GeO2, an oxide glass with several unique properties and applications, described below and in linked articles:
Fiber optics
A notable derivative of GeCl4 is germanium dioxide. In the manufacture of optical fibers, silicon tetrachloride, SiCl4, and germanium tetrachloride, GeCl4, are introduced with oxygen into a hollow glass preform, which is carefully heated to allow for oxidation of the reagents to their respective oxides and formation of a glass mixture. The GeO2 has a high index of refraction, so by varying the flow rate of germanium tetrachloride the overall index of refraction of the optical fiber can be specifically controlled. The GeO2 is about 4% by weight of the glass.
References
See also
Germanium
Optical fiber
Infrared
Germanium(IV) compounds
Chlorides
Metal halides
Nonmetal halides | Germanium tetrachloride | Chemistry | 582 |
8,701,933 | https://en.wikipedia.org/wiki/Global%20Health%20Security%20Initiative | The Global Health Security Initiative (GHSI) is a collaborative effort among several nations and organizations focused on strengthening global health security. Established in response to the 2001 terrorist attacks, its primary goal is to prepare for and address public health risks related biological, chemical, nuclear terrorism, or pandemics. The initiative includes members from North America, Europe, and Asia, with the World Health Organization participating as an observer.
History
The idea on which the Global Health Security Initiative is based was suggested by then US Secretary of Health and Human Services, Tommy Thompson, after the World Trade Center attacks on 11 September 2001. He proposed that countries fighting bioterrorism should collaborate, share information, and coordinate their efforts in order to best protect global health.
GHSI was launched in November 2001 by Canada (who hosted the first meeting in Ottawa), the European Commission, France, Germany, Italy, Japan, Mexico, the United Kingdom, and the United States. The World Health Organization (WHO) would act as observer to the GHSI. The ministers agreed on eight areas in which the partnership could collaborate in order to "strengthen public health preparedness and response to the threat of international biological, chemical and radio-nuclear terrorism."
In December 2002, at a meeting in Mexico City, the Ministers broadened the scope of the mandate to include the public health threat posed by pandemic influenza.
Aims and scope
GHSI states that its mandate is "to undertake concerted global action to strengthen public health preparedness and response to chemical, biological, radiological, and nuclear (CBRN) threats, as well as pandemic influenza," including intentional, accidental, and naturally occurring events.
Organization
The Global Health Security Action Group (GHSAG) is made up of senior officials from each member country. The GHSI Secretariat organises, manages, and administers meetings and committees and sets priorities.
Various technical and scientific working groups focus on specific areas of knowledge. Current working groups include:
Chemical Events Working Group: focuses on the risk prioritization of chemicals, the identification of research needs and best practices in the area of medical countermeasures, as well as other cross-hazard projects such as early alerting and reporting.
Biological Working Group: focuses on addressing existing gaps and research and development needs required for GHSI member countries to prepare for and respond to biological threats, excluding pandemic influenza and other respiratory viruses of pandemic potential.
Laboratory Network: focuses on promoting quality assurance in diagnostics, flexibility and adaptability of techniques and technologies, and addressing issues regarding transport of specimens.
Radio-Nuclear Threats Working Group: focuses on collaboration with other radiation protection and nuclear safety authorities on emergency preparedness, undertakes projects in areas such as countermeasures and laboratory mapping, and serves as an informal communication network during emergencies.
Pandemic Influenza Working Group: focuses on sharing and comparing respective national approaches to pandemic preparedness, including vaccine and anti-viral stockpiling and use, surveillance and epidemiology, diagnostics, and public health measures.
Research
GHSI conducts research and collaborates to address global health security concerns. Some of the research GHSI has been involved in includes:
Research on mass casualties since the release of Opioids: The GHSI participated in research to explore the significant health threats linked to the increasing availability of synthetic opioids. The research highlights the dual risks of these substances contributing to mass casualty incidents, either through unintentional overdose or intentional misuse as weapons. In response to these challenges, the GHSI Chemical Events Working Group organized a workshop in 2018 to evaluate the current state of preparedness for handling large-scale incidents involving Opioids.
Development of SCRIPT: Screening Categorization Risk Prioritization Tool (SCRIPT) is designed to assess public health risks associated with the release of airborne chemicals.
See also
Biosecurity
Bioterrorism
CBRN defense
Centers for Disease Control and Prevention (United States)
Council of Europe Convention on the Prevention of Terrorism
Emergent virus
European Centre for Disease Prevention and Control (EU)
Health Threat Unit (EU)
Pandemic
References
Sources
External links
Working Together to Counter Global Health Threats Event featuring Michael Leavitt, Secretary of the U.S. Department of Health and Human Services, at the Woodrow Wilson Center in October 2007.
Public health organizations
Nuclear warfare
Biological warfare
Chemical warfare
International medical and health organizations
International organizations based in Canada
Radiation protection organizations | Global Health Security Initiative | Chemistry,Engineering,Biology | 902 |
34,365,923 | https://en.wikipedia.org/wiki/Robot%20Framework | Robot Framework is a generic software test automation framework for acceptance testing and acceptance test-driven development (ATDD). It is a keyword-driven testing framework that uses tabular test data syntax.
History
The basic ideas for Robot Framework were shaped in Pekka Klärck's masters thesis in 2005. The first version was developed at Nokia Networks the same year. Version 2.0 was released as open source software June 24, 2008 and version 3.0.2 was released February 7, 2017.
The framework is written using the Python programming language and has an active community of contributors. It is released under Apache License 2.0 and can be downloaded from robotframework.org.
In 2020 survey it scored 8 among 12 test automation frameworks, with 3 % of respondents using it. In 2021 it had fallen to 18 among 22 with 2 % usage.
Description
Test cases are written using a keyword-testing methodology written in a tabular format. These tables can be written in plain text, tab-separated values (TSV), or reStructuredText (reST) formats files in any text editor or using the Robot Integrated Development Environment (RIDE). RIDE simplifies writing test cases by providing framework-specific code completion, syntax highlighting, etc.
Examples
The following test case implements a Hello, World! example:
*** Test Cases ***
Demo
Log Hello world
Log is a built-in keyword that logs the given parameter to the test report generated by Robot Framework.
With SeleniumLibrary, writing tests for web applications is very easy too:
*** Test Cases ***
Demo
Open Browser https://www.google.com ie
Input Text id=lst-ib Hollywood Celebrities
Click Button Google Search
This test opens a new Internet Explorer browser window with Google and performs an Internet search for "Hollywood Celebrities" by pressing the button "Google Search".
With Robot Framework Browser, automation can be done with Chromium, WebKit and Firefox.
*** Settings ***
Library Browser
*** Test Cases ***
Example Test
New Page https://playwright.dev
Get Text h1 == 🎭 Playwright
Add-ons
These libraries are best implemented in Python, but using Java or .NET is also possible.
Other languages such as Perl, JavaScript, and PHP can be used for libraries as well, using the documented remote library interface.
See also
Acceptance testing
Keyword-driven testing
Data-driven testing
Test-driven development
References
External links
Free software programmed in Python
Software testing
Free software testing tools
Software using the Apache license | Robot Framework | Engineering | 529 |
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