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57,813,311 | https://en.wikipedia.org/wiki/Claudia%20Sheinbaum | Claudia Sheinbaum Pardo (born 24 June 1962) is a Mexican politician, scientist, and academic who is serving as the 66th president of Mexico since 1 October 2024, the first woman to hold the office. She previously served as Head of Government of Mexico City from 2018 to 2023.
A scientist by profession, Sheinbaum received her Doctor of Philosophy in energy engineering from the National Autonomous University of Mexico (UNAM). She has authored over 100 articles and two books on energy, the environment, and sustainable development. She contributed to the Intergovernmental Panel on Climate Change and, in 2018, was named one of BBC's 100 Women.
In 1989, Sheinbaum joined the Party of the Democratic Revolution (PRD). From 2000 to 2006, Sheinbaum served as secretary of the environment in Mexico City under Andrés Manuel López Obrador, who was then head of government. In 2014, she left the PRD and joined López Obrador's splinter movement, Morena. She was mayor of the Tlalpan borough from 2015 to 2017. She was elected head of government of Mexico City in the 2018 election, where she ran a campaign that emphasized curbing crime and enforcing zoning laws.
In June 2023, Sheinbaum resigned from her position as head of the city government to seek Morena's presidential nomination in the 2024 election. In September 2023, she secured the party's nomination over her closest opponent, former foreign secretary Marcelo Ebrard. In June 2024, Sheinbaum won the general election in a landslide against the National Action Party (PAN) candidate Xóchitl Gálvez. She assumed office on 1 October 2024.
Early life and family
Claudia Sheinbaum Pardo was born on 24 June 1962, in Mexico City, within a secular Mexican Jewish family. She is the second child of the marriage between chemist Carlos Sheinbaum Yoselevitz and biologist Annie Pardo Cemo.
Carlos Sheinbaum was of Ashkenazi Litvak descent, with his father emigrating from Lithuania in 1928. His father was a jewelry merchant and was a member of the Mexican Communist Party. Annie Pardo is from a family of assimilated Sephardic Bulgarian Jews who arrived in Mexico in 1942, fleeing from the persecution of Jews during World War II. Pardo became the first Sephardic woman in the Mexican academic world.
Claudia's parents were actively involved in Mexican left-wing circles during the 1960s, participating in protests, workers' movements, and student uprisings.
Sheinbaum has two siblings. Her older brother, Julio, is a physicist and physical oceanography researcher at CICESE. Her younger sister, Adriana, is a teacher who lives in the United States and is married to director Rodrigo García Barcha.
Academic career
Sheinbaum earned an undergraduate degree in physics at UNAM in 1989, a master's degree in 1994, and a Ph.D. in energy engineering in 1995.
Sheinbaum completed the work for her Ph.D. thesis between 1991 and 1994 at the Lawrence Berkeley National Laboratory in California. While working for the laboratory, she analyzed energy use in the Mexican transportation sector and published studies on the trends in Mexican building energy use.
In 1995, she joined the faculty of the Institute of Engineering at UNAM. In 1999, she received the prize for being the best UNAM young researcher in engineering and technological innovation.
In 2006, Sheinbaum returned to UNAM after a period in government and began publishing articles in scientific journals.
In 2007, she contributed to the "Industry" chapter of the WG3 (Mitigation) report of the Intergovernmental Panel on Climate Change 4AR and, in 2013, a lead author for the chapter in the IPCC Fifth Assessment Report.
Early political career
During her time as a student at UNAM, Sheinbaum was a member of the University Student Council (), a group of students that would become the founding youth movement of the Party of the Democratic Revolution (PRD).
Sheinbaum served as the Secretary of the Environment of Mexico City from 5 December 2000 to 15 May 2006, appointed on 20 November 2000 to the cabinet of the Head of Government of Mexico City, Andrés Manuel López Obrador. During her term, which concluded in May 2006, she was responsible for constructing an electronic vehicle registration center for Mexico City. She also oversaw the introduction of the Metrobús, a bus rapid transit system with dedicated lanes, and the building of the second story of the Anillo Periférico, Mexico City's ring road.
López Obrador included Sheinbaum in his proposed cabinet for the Secretariat of Environment and Natural Resources as part of his campaign for the 2012 presidential election. In 2014, she joined López Obrador's splinter movement, which broke away from the mainstream left-wing party, the Party of the Democratic Revolution.
Mayor of Tlalpan
From the end of 2015, Sheinbaum served as the mayor of Tlalpan. She resigned from the position in 2017 upon receiving the nomination for the candidacy of the mayor of Mexico City for the () coalition, consisting of the National Regeneration Movement (MORENA), the Labor Party (PT), and the Social Encounter Party (PES).
Chapel demolition
On 29 April 2016, during Sheinbaum's tenure as mayor of Tlalpan, city staff were ordered to demolish a wall that had been built illegally adjacent to a chapel () in Tlalpan's Cultura Maya neighborhood. The workers instructed to demolish the wall also destroyed part of the chapel's structure, including its sheet metal roof, and removed religious images. Juan Guillermo Blandón Pérez, the parish priest, alleged that Sheinbaum was responsible for demolishing the chapel and claimed that it was carried out without prior notification.
Days after the chapel's demolition, borough authorities acknowledged their error. Sheinbaum met with church representatives and proposed dividing the property in half to build a new chapel and a community art center.
Enrique Rébsamen School collapse
The Colegio Enrique Rébsamen, a private school in Tlalpan, collapsed during the 2017 Puebla earthquake, killing 19 children and seven adults. In September 2016, during Sheinbaum's term as mayor, the city's Institute for Administrative Verification had ruled that the school's building infringed zoning regulations and was built higher than was allowed and that the owner, Mónica García Villegas, had presented falsified documents. Sheinbaum faced criticism for not providing a complete account of the permits for the school's land use, construction, and operation. Enrique Fuentes, a lawyer representing the deceased children's parents, stated that the mayor had an obligation to take action but had failed to do so, allowing the school to continue operating.
2018 campaign for the Head of Government of Mexico City
In August 2017, Sheinbaum participated in a poll by the National Regeneration Movement to determine the party's candidate for the Head of Government of Mexico City. The other contenders were Martí Batres, Mario Delgado, and Ricardo Monreal. Sheinbaum secured first place with 15.9% of the vote, beating her closest opponent, Batres, by 5.8 points. On 5 December 2017, Sheinbaum stepped down as mayor of Tlalpan to register her pre-candidacy.
At her campaign launch on 1 April 2018, Sheinbaum prioritized fighting crime, stating that she would hold regular public hearings, publish reported crime statistics, and rely on the Security Council for guidance. She committed to generating 1 million jobs during her term, maintaining the universal pension for seniors, and expanding the Mexico City Metrobús system to connect the city's outskirts with the center.
During the campaign period, Sheinbaum was accused by members of of being culpable for the collapse of the Colegio Enrique Rébsamen, a private school in Tlalpan, during the 2017 Puebla earthquake.
On 1 July 2018, Sheinbaum was elected to a six-year term as the Head of Government of Mexico City with 47.08% of the vote, defeating six other candidates.
Head of Government of Mexico City (2018–2023)
On 5 December 2018, Sheinbaum was inaugurated as Mexico City's head of government. She became the first female head of government and the first to come from a Jewish background.
Sheinbaum's administration was characterized by a strong relationship with the federal government and President López Obrador. However, she took distinct approaches to certain issues, such as managing the COVID-19 pandemic, where her scientific background shaped the city's response to the crisis.
Sheinbaum stepped down on 16 June 2023 to contend with the internal selection process for a presidential candidate for the Morena-led coalition, . Sheinbaum recommended Martí Batres as substitute head of government, a choice later ratified by the Congress of Mexico City.
Crime and policing
Sheinbaum addressed security concerns through four key axes: addressing root causes, which was integrated with her education policy and included initiatives like the and the community centers; enhancing the quality and quantity of police forces; expanding intelligence and investigative capabilities; and improving coordination between the Attorney General's Office, mayors, and the Secretariat of Security and Civilian Protection.
Her tenure witnessed the resignation and subsequent arrest warrant for Jesús Orta, former head of the Secretariat of Citizen Security, on corruption charges stemming from his time in the Federal Police; the escape of three inmates from the Sinaloa Cartel; and the femicide of Ingrid Escamilla.
In the first 52 months of her term, Mexico City saw 5,078 homicides, a figure higher than those recorded under the administrations of Andrés Manuel López Obrador, Marcelo Ebrard, and Miguel Ángel Mancera. Despite this, the homicide rate was reduced from 17.9 per 100,000 people in 2018 to 8.6 in 2022.
Gender violence
In 2019, Sheinbaum declared a gender violence alert in Mexico City, responding directly to the outcry over violence against women. This decision was accompanied by the creation of the SOS *765 hotline and the construction of 710 kilometers of safe pathways under the slogan "Walk Free, Walk Safe," designed to ensure women's safety as they move around the city.
Voluntary disarmament
Sheinbaum promoted the () gun buyback program aimed at reducing the number of firearms held by civilians and thereby decreasing related crimes. The program allowed citizens to anonymously exchange their weapons, whether acquired legally or otherwise, for cash. Under her administration, the program, which cost about MX$40 million, managed to recover about 6,546 firearms, including 1,315 long guns.
Organized crime
Sheinbaum's administration focused on dismantling criminal organizations such as the Jalisco New Generation Cartel, La Unión Tepito, and La Fuerza Anti-Unión, managing to arrest several of their members. Analysts viewed these actions as evidence of the effectiveness of the intelligence strategy led by Secretary of Citizen Safety Omar García Harfuch.
Her administration's security strategy included the gradual deployment of the National Guard in Mexico City. While some experts believed that the policy had a positive impact on crime reduction, others argued that there was insufficient evidence to determine the National Guard's effectiveness in reducing violence. They suggested that its presence might be more about preventive rhetoric than concrete outcomes.
Education
As part of her administration's education policy, the () scholarship program was created for 1.2 million students from preschool to secondary education and, in 2022, was elevated to constitutional law in Mexico City. For higher education, the and the University of Health were established.
Community centers called () were established in marginalized neighborhoods and towns. These spaces promoted arts, sports, education, and cultural activities and were recognized with an award from UNESCO in 2021.
Environment
In June 2019, Sheinbaum announced a new six-year environmental plan to reduce air pollution by 30%, plant 15 million trees, ban single-use plastics and promote recycling, build a new waste separation plant, provide water service to every home, construct 100 kilometers of trolleybus and metrobús-only corridors, and construct and install solar panels and water heaters.
Infrastructure
Public transportation
Sheinbaum introduced the Cablebús cable car system, becoming a new form of public transportation for the city. Construction on Lines 1 and 2 started in 2019, and both lines were inaugurated in 2021. Line 3 was proposed by Sheinbaum in 2021, and construction began that same year.
Sheinbaum continued the expansion of Line 12 towards the Observatorio metro station, a project initiated by the previous administration. In 2022, she started the modernization of Mexico City Metro Line 1 with a MX$37 billion investment, temporarily closing portions of the line to replace tracks, acquire new trains, and implement a new control system. The Observatorio station was also closed to transform it into a mega terminal, connecting Metro Lines 1, 12, and El Insurgente.
Sheinbaum expanded the Metrobús network by 33 kilometers across three of its lines. She also introduced electric buses to the system, making Line 3 entirely electric, and purchased low-emission vehicles for the city's Red de Transporte de Pasajeros.
The use of bicycles was promoted through the construction of 200 kilometers of bike lanes, primarily on the city's outskirts, along with six bike stations and the acquisition of 2,500 new bicycles for the Ecobici system.
Sheinbaum introduced a single mobility card for all public transportation systems.
Roads and highways
Sheinbaum announced the construction of vehicular bridges to improve road connectivity. Three notable projects included the Cuemanco Bridge, which connected Periférico Oriente with Canal Nacional; a new junction linking Circuito Interior with Eje 6; and Las Adelitas Bridge, which connected Circuito Interior with Gran Canal.
Criticism
Sheinbaum faced criticism for the management of the budget allocated to public transportation. Although she claimed that there were no cuts and that resources for the Metro were increased, budget data showed fluctuations in the allocation of funds for different transportation systems between 2018 and 2023.
Other infrastructure projects, such as the renovation of Mexico City Metro Line 1, the extension of Mexico City Metro Line 12 to Observatorio, the construction of the Mexico-Toluca Interurban Train, and Line 3 of the Cablebús, remained incomplete at the time of her resignation to seek her party's presidential nomination.
Social issues
In 2019, Sheinbaum implemented a gender-neutral uniform policy for students in state-run schools, allowing them to wear uniforms of their choice regardless of gender. In 2021, Sheinbaum removed a statue of Christopher Columbus from Mexico City's Paseo de la Reforma as part of what she called a "decolonization" exercise.
Crisis management
COVID-19 pandemic response
Shortly after the first COVID-19 case in Mexico City was confirmed on 28 February 2020, Sheinbaum addressed the city, emphasizing that although the risk was low, the population needed to stay informed through official sources. On 19 March, Sheinbaum urged residents to stay at home to prevent the spread of infection. She also advised those with symptoms to text a hotline for guidance instead of going to hospitals to avoid overwhelming the healthcare system. On 22 March, Sheinbaum announced the closure of commercial establishments, cultural venues, sports facilities, and religious spaces.
López Obrador and Sheinbaum had differing views on using face masks: Sheinbaum encouraged Mexico City residents to wear face masks, while López Obrador frequently did not wear them in public.
Sheinbaum was nominated by the City Mayors Foundation for the World Mayor Prize in 2021 in North America for her handling of the COVID-19 pandemic in Mexico.
Collapse of Line 12 of the Mexico City Metro
At around 10:22 p.m. on 3 May 2021, several girders, part of the tracks, and two wagons of Line 12 of the Mexico City Metro collapsed between the Olivos and Tezonco stations. The casualties were 26 dead, 80 injured, and five missing. Line 12 of the Metro was inaugurated on 30 October 2012 by the head of government of Mexico City, Marcelo Ebrard, and the president of Mexico, Felipe Calderón.
Engineering flaws that had existed since before the line's inauguration became worse over time, necessitating maintenance repairs over the next three years, including an unprecedented closure of the line to re-shape some sections of tracks and to replace the rails; most of these improvements were carried out during the term of Miguel Ángel Mancera as Head of Government. On 4 May 2021, Ebrard, then serving as Secretary of Foreign Affairs, said that the work was definitively delivered in July 2013, after reviews carried out for seven months, and expressed his willingness to respond and collaborate in the event of any request from the authorities.
Det Norske Veritas (DNV), a Norwegian company in charge of investigating the causes of the collapse of Metro Line 12, detected that one of the beams that collapsed already had structural failures since before the earthquake of 19 September 2017, a factor that had caused problems in the elevated section of the line that collapsed. On 28 June 2021, Sheinbaum dismissed the general director of the Mexico City Metro, .
Some critics said Sheinbaum and other leaders should have worked harder to improve the Metro's infrastructure. Some political observers suggested that the political fallout from the disaster could harm Sheinbaum's candidacy in the 2024 presidential election. Alejo Sánchez Cano, editor of the Mexico City daily newspaper , opined that Sheinbaum's responsibility was unavoidable, stating that after having been in office for two and a half years, she failed to maintain the Metro system.
2024 presidential campaign
Nomination
On 12 June 2023, Sheinbaum announced that she would resign as head of government of Mexico City on 16 June to contend in the internal selection process to select a de facto presidential candidate for Juntos Hacemos Historia, a coalition encompassing Morena, the Labor Party, and the Ecologist Green Party of Mexico. Speculation regarding her nationality emerged after former president Vicente Fox referred to her as a "Bulgarian Jew". In response, Sheinbaum released her birth certificate, showing she was born in Mexico City.
The coalition's internal process consisted of five polls from 28 August to 4 September. On 6 September, Sheinbaum was declared the winner, securing 39.38% of the vote and defeating her closest opponent, former foreign secretary Marcelo Ebrard, by around 13 points. On 19 November 2023, Sheinbaum registered as the sole precandidate of Sigamos Haciendo Historia, the successor coalition to Juntos Hacemos Historia. Sheinbaum formally registered her candidacy at the National Electoral Institute (INE) on 18 February 2024.
General election
On 1 March 2024, Sheinbaum launched her campaign at the Zócalo, outlining her proposals and emphasizing her commitment to continuing President López Obrador's Fourth Transformation policies. She pledged to pass "Plan C," a package of eighteen constitutional amendments proposed by López Obrador earlier that year, which include increasing the minimum wage above inflation, elevating social programs to constitutional law, and electing judiciary members by popular vote. She also proposed replicating her Mexico City security strategy nationwide, introducing a constitutional amendment to prevent reelection for any popularly elected position, and implementing new social programs for students from preschool to secondary education and women aged 60 to 64.
During debates and the campaign, Sheinbaum was accused by Xóchitl Gálvez, the candidate from the opposition coalition Fuerza y Corazón por México, of being responsible for the collapse of the Colegio Rébsamen during the 2017 Puebla earthquake, the Mexico City Metro overpass collapse, and the excess deaths during the COVID-19 pandemic in Mexico City.
Polls consistently indicated that Sheinbaum held a substantial lead over her main opponent, Xóchitl Gálvez. During the three presidential debates, many commentators praised her calm demeanor during provocations from Gálvez.
The election took place on 2 June 2024, with Sheinbaum being projected the winner by the INE's quick count at 11:50 CST, making her the virtual president-elect. On 6 June, district tallies confirmed that Sheinbaum won a landslide victory. She received the highest number of votes ever recorded for a candidate in Mexican history, carried 31 out of 32 states, and achieved the highest vote percentage since free and fair elections began in Mexico.
Presidential transition
Following her victory, Sheinbaum met with President López Obrador to outline the presidential transition and her legislative agenda for the early months of her administration. She detailed that her priorities included new social programs for primary school students and women aged 60 to 64, modifications to the pension system for government employees, and a ban on reelection for any popularly elected position. While Sheinbaum voiced support for López Obrador's judicial reform, she agreed to open nine discussion forums to address its most controversial aspects.
Sheinbaum rolled out her cabinet appointments in phases, beginning with the first announcements on 20 June. In early August, she met with governors and governors-elect to outline key projects for her 2025 budget. Sheinbaum also pledged to continue López Obrador's morning press conferences, known as mañaneras, at 7:00 AM CST.
After the LXVI Legislature was sworn in on 1 September, several of her campaign promises that stemmed from López Obrador's "Plan C" were either fully or partially passed by Congress. The judicial reform and the transfer of the National Guard to the Secretariat of National Defense were passed by both chambers, while the increases in the minimum wage above inflation and the elevation of certain social programs to constitutional status were approved solely by the Chamber of Deputies.
Presidency (2024–present)
Inauguration
Sheinbaum was sworn in as president on 1 October 2024, becoming the first woman, as well as the first person of predominantly Jewish heritage, to hold the office. The presidential sash was handed to her by Ifigenia Martínez, the president of the Congress of the Union and a prominent figure for the Mexican left. In her address to Congress, Sheinbaum thanked her predecessor, highlighted her historic election as the first woman to the presidency, pledged responsible fiscal policies, and reassured foreign investors.
Her inauguration was attended by 105 representatives from various countries, including 16 heads of state and 23 delegates from international organizations. Notable attendees included Brazilian President Lula da Silva, Chilean President Gabriel Boric, Colombian President Gustavo Petro, former German President Christian Wulff, and US First Lady Jill Biden. King Felipe VI of Spain was controversially not invited, with Sheinbaum citing his failure to respond to López Obrador's 2019 letter requesting an apology for the abuses committed during the Spanish conquest. This prompted a boycott by the Spanish government.
Domestic policy
Sheinbaum continued her predecessor's practice of holding "", regular press briefings in the morning.
On 2 October 2024, the anniversary of the Tlatelolco massacre, Sheinbaum issued a decree acknowledging the State's responsibility for the killings. The decree included a public apology, which was delivered by Secretary of the Interior Rosa Icela Rodríguez.
Crime and the drug war
Sheinbaum announced a data-driven strategy to combat crime, focusing on improved policing, intelligence, and addressing root causes through increased social spending, mirroring her approach as Head of Government of Mexico City. She appointed Omar García Harfuch to head the Secretariat of Security and Civilian Protection's (SSCP), a role he previously held in her Mexico City cabinet, where he was credited with halving the city's homicide rate. On 31 December 2024, she published a bill that expanded the SSCP's powers, enabling greater collaboration with the Attorney General's Office and improving intelligence gathering across all levels of government.
During her first weeks in office, Sheinbaum's administration adopted a more hard-handed approach toward organized crime, marking a departure from Andrés Manuel López Obrador's "hugs, not bullets" strategy. Confrontations between government forces and organized crime increased, resulting in the capture of high-ranking cartel figures but occasionally causing accidental civilian casualties. Sheinbaum defended operations with lopsided death tolls, such as a shootout where the military remained unharmed while killing 19 cartel members, as acts of self-defense. By her first 100 days in office, the government reported the arrest of 7,720 individuals, the seizure of 66 tons of drugs, and the dismantling of 115 methamphetamine laboratories.
In response to infighting within the Sinaloa Cartel, Sheinbaum dispatched a task force composed of Mexican Army soldiers, National Guard members, and agents from the National Intelligence Center to address the violence.
Energy
On 30 October 2024, Sheinbaum published a constitutional amendment reestablishing the Federal Electricity Commission (CFE) and Pemex as public entities, effectively reversing much of the 2013 energy reform. The amendment mandates that the CFE maintain a 54% share of electricity generation, with the remaining 46% managed by private companies under regulated conditions to prioritize public needs over profit.
Government reform
Amidst the release of a Supreme Court draft opinion proposing to partially overturn the judicial reform bill passed by Andrés Manuel López Obrador in his final weeks as president, Sheinbaum asserted that the judicial branch lacked authority over constitutional amendments. In response, on 31 October 2024, she published a bill enshrining constitutional supremacy, limiting legal challenges to constitutional amendments strictly to procedural grounds.
On 20 December 2024, Sheinbaum signed a bill that dissolved autonomous bodies overseeing telecommunications, economic competition, and transparency, as part of an effort to simplify government functions. This followed an earlier bill she signed that restructured several cabinet positions to absorb the responsibilities of these entities. Among these changes, the Secretariat of the Civil Service was transformed into the Secretariat of Anticorruption and Good Governance, taking over the duties and authority of the National Institute of Transparency for Access to Information and Personal Data Protection (INAI). Three new cabinet positions were also added: the Secretariat of Women (replacing the ), the Secretariat of Science, Humanities, Technology, and Innovation (replacing CONAHCYT), and the Digital Transformation and Telecommunications Agency.
Infrastructure and passenger rail
Sheinbaum committed to further expanding Mexico's passenger rail network, publishing a constitutional amendment that restored the Mexican State's authority to use railway lines for passenger transport services. In late 2024, she inaugurated the final sections of the Tren Maya and announced plans to integrate freight services into the train's operations while extending the network toward Progreso, Yucatán. She also outlined her goal to construct approximately 3,000 kilometers of railroad, comprising the Mexico–Pachuca, Mexico–Nuevo Laredo, and Mexico–Nogales lines, to be completed in four phases.
In 2024, Sheinbaum announced a MX$33 billion investment to modernize six ports across Mexico: Ensenada, Baja California; Manzanillo, Colima; Lázaro Cárdenas, Michoacán; Acapulco, Guerrero; Veracruz, Veracruz; and Progreso, Yucatán.
Sheinbaum has continued her predecessor's practice of employing SEDENA's Military Engineers Corps. to build government infrastructure projects.
Welfare
During the early months of her tenure, Sheinbaum introduced the Women's Wellbeing Pension (Pensión Mujeres Bienestar), providing bimonthly financial assistance to senior women aged 60 to 64, and launched the House to House Health (Salud Casa a Casa) program, offering medical care to the elderly and people with disabilities. She also renamed the Benito Juárez Scholarship (Beca Benito Juárez) to the Rita Cetina Gutiérrez Universal Scholarship (Beca Universal Rita Cetina Gutiérrez), expanding it to provide bimonthly financial aid to all families with children enrolled in the public basic educational system. On 2 December 2024, Sheinbaum elevated several social programs to constitutional law.
On 22 October 2024, Sheinbaum announced the fusion of SEGALMEX and DICONSA into Food for Wellbeing () to support small local producers, offer quality products at affordable prices, and contribute to food self-sufficiency. With the fusion, the over 24,500 DICONSA stores, present in 90% of the municipalities of the country, will be reorganized, rehabilitated, and rebranded to Wellbeing Stores to Generate Happiness ().
Foreign policy
In November 2024, Sheinbaum took her first trip abroad as president to attend the G20 summit. At the summit, she proposed allocating 1% of global military spending to reforestation efforts and advocated for expanding the United Nations Security Council to include seats for Africa, Latin America, the Caribbean, and small island nations. Sheinbaum also held bilateral meetings with U.S. President Joe Biden, Canadian Prime Minister Justin Trudeau, Chinese President Xi Jinping, French President Emmanuel Macron, and the leaders of MIKTA member states.
Israel–Palestine conflict
On 12 October 2024, Sheinbaum expressed support for the two-state solution in the ongoing Israel–Palestine conflict, emphasising that recognising both Israel and Palestine was necessary for achieving peace in the Middle East. She also condemned the October 7 Hamas-led attack on Israel, the subsequent violence against Gaza, and other acts of aggression in the region. Like her predecessor, Sheinbaum maintained a stance of neutrality, calling for a more proactive role from the United Nations.
United States
In October 2024, diplomatic relations with the U.S. ambassador to Mexico, Ken Salazar, resumed, which had been suspended due to U.S. criticism of Mexico's judicial reforms. Sheinbaum outlined new diplomatic protocols requiring Salazar to communicate with the Secretariat of Foreign Affairs to engage with the federal government, noting that previously, the ambassador had spoken directly with members of the Mexican cabinet.
On 6 November 2024, Sheinbaum congratulated Donald Trump on his victory in the 2024 United States presidential election. Following the announcement of a 25% tariff on Mexican imports, she sent Trump a letter warning that "one tariff will follow another in response and so on, until we put our common businesses at risk." She also highlighted the continued flow of firearms from the United States to criminal groups in Mexico.
Political views
Social issues
Sheinbaum is a self-described feminist, aligning her beliefs and actions with the principles of gender equality and women's rights. She advocates for the legalization of abortion, aligning her stance with broader movements aimed at promoting reproductive rights and autonomy for women. During her leadership in Mexico City, Sheinbaum implemented a gender-neutral policy regarding school uniforms in state-run schools and championed LGBT rights. In 2022, she became the first Head of Government of Mexico City to attend the city's gay pride march.
Economy
Sheinbaum has criticized the neoliberal economic policies of past presidents of Mexico, arguing that they have contributed to inequality in the country. She has promised to expand welfare under her presidency and intends to continue programs started by López Obrador, such as universal pension.
Environment
Sheinbaum has a background in environmental policy, having served as Minister of the Environment for Mexico City and worked on the Intergovernmental Panel on Climate Change (IPCC), which would go on to win the panel a Nobel Peace Prize. In her tenure as Minister of the Environment, she saw a marked reduction in air pollution and created community ecological reserves. She has both spoken in favor of clean energy and support of oil, praising PEMEX (the nation's state-owned oil company).
Personal life
In 1986, Sheinbaum met Carlos Ímaz Gispert, who later became a prominent political figure in the PRD during his tenure at Stanford University. They married in 1987 and divorced in 2016. They have a daughter, Mariana Ímaz Sheinbaum, born in 1988. Through the marriage, Sheinbaum became the stepmother to Ímaz's son from a previous marriage, Rodrigo Ímaz, who she raised.
In 2016, she began dating Jesús María Tarriba Unger, a financial risk analyst for the Bank of Mexico, who she had known as a university student.
In November 2023, Sheinbaum announced her marriage to Tarriba via social media. The two married in a small civil ceremony.
Awards and honours
Sheinbaum featured in the Forbes 2024 list of World's 100 most powerful women and was ranked 4th.
National honour
:
Grand Master and Collar of the Order of the Aztec Eagle (1 October 2024).
Selected bibliography
Sheinbaum is the author of over 100 articles and two books on energy, the environment, and sustainable development. A selection follows:
Consumo de energía y emisiones de del autotransporte en México y Escenarios de Mitigación, Ávila-Solís JC, Sheinbaum-Pardo C. 2016.
Decomposition analysis from demand services to material production: The case of emissions from steel produced for automobiles in Mexico, Applied Energy, 174: 245–255, Sheinbaum-Pardo C. 2016.
The impact of energy efficiency standards on residential electricity consumption in Mexico, Energy for Sustainable Development, 32:50–61 Martínez-Montejo S.A., Sheinbaum-Pardo C. 2016.
Science and Technology in the framework of the Sustainable Development Goals, World Journal of Science, Technology and Sustainable Development, 14:2 – 17. Imaz M. Sheinbaum C. 2017.
Assessing the Impacts of Final Demand on -eq Emissions in the Mexican Economy: An Input-Output Analysis, Energy and Power Engineering, 9:40–54, Chatellier D, Sheinbaum C. 2017.
Electricity sector reforms in four Latin-American countries and their impact on carbon dioxide emissions and renewable energy, Ruíz- Mendoza BJ, Sheinbaum-Pardo C. Energy Policy, 2010
Energy consumption and related emissions in five Latin American countries: Changes from 1990 to 2006 and perspectives, Sheinbaum C, Ruíz BJ, Ozawa L. Energy, 2010.
Mitigating Carbon Emissions while Advancing National Development Priorities: The Case of Mexico, C Sheinbaum, O Masera, Climatic Change, Springer, 2000.
Energy use and emissions for Mexico's cement industry, C Sheinbaum, L Ozawa, Energy, Elsevier, 1998.
Energy use and emissions in Mexico's iron and steel industry, L Ozawa, C Sheinbaum, N Martin, E Worrell, L Price, Energy, Elsevier, 2002.
New trends in industrial energy efficiency in the Mexico iron and steel industry, L Ozawa, N Martin, E Worrell, L Price, C Sheinbaum, OSTI, 1999.
Mexican Electric end-use Efficiency: Experiences to Date, R Friedmann, C Sheinbaum, Annual Review of Energy and the Environment, 1998.
Incorporating Sustainable Development Concerns into Climate Change Mitigation: A Case Study, OR Masera, C Sheinbaum, Climate Change and Development, UDLAP, 2000.
Notes
References
External links
Biography by CIDOB
1962 births
Living people
20th-century Mexican engineers
21st-century Mexican engineers
21st-century Mexican scientists
21st-century women engineers
21st-century women presidents
Academic staff of the National Autonomous University of Mexico
Climate change mitigation researchers
Female heads of state
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Intergovernmental Panel on Climate Change contributing authors
Jewish mayors
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Politicians from Mexico City
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Women governors of States of Mexico
Women mayors of places in Mexico | Claudia Sheinbaum | [
"Engineering"
] | 7,412 | [
"Geoengineering",
"Climate change mitigation researchers"
] |
57,813,396 | https://en.wikipedia.org/wiki/HD%2036112 | HD 36112, also known as MWC 758, is a young Herbig Ae star located in the constellation Taurus, surrounded by irregular rings of cosmic dust. The system is about 3.5 million years old. The disk has a cavity at 50 astronomical units and two spiral arms at 30-75 au that are seen in near-infrared scattered light, but only one spiral arm is seen in ALMA images.
The inner cavity was shown to be elliptical and not perfectly circular. This is not a projection effect but represents the shape of the cavity, with an eccentricity e ≈ 0.1 after the deprojection of the disk.
A 2018 study detected a possible exoplanet at a distance of about 20 au, designated MWC 758 b, and the observations with ALMA have also shown evidence of an unseen planet at 100 au. A study in 2019 came to the conclusion that a 1.5 planet at 35 au and a 5 planet at 140 au could explain the features seen with ALMA and the VLA.
In another 2019 study, a possible exoplanet or disk feature was detected with the Large Binocular Telescope, referred to as MWC 758 CC1 (Companion Candidate 1), with a non-detection of MWC 758 b. However, another study in 2021 failed to detect either of the point sources found in earlier studies. A 2023 study found further evidence for MWC 758 CC1, now designated MWC 758 c, orbiting at a distance of approximately 100 au.
References
Taurus (constellation)
A-type main-sequence stars
Herbig Ae/Be stars
036112
025793 | HD 36112 | [
"Astronomy"
] | 340 | [
"Taurus (constellation)",
"Constellations"
] |
57,813,559 | https://en.wikipedia.org/wiki/RXC%20J2211.7-0350 | RXC J2211.7-0350 is a cluster of galaxies. Galaxy clusters are the biggest objects in the Universe that are held together by gravity.
See also
Brightest cluster galaxy
Galaxy groups
Galaxy clusters
List of galaxy clusters
References
Galaxy clusters
Aquarius (constellation) | RXC J2211.7-0350 | [
"Astronomy"
] | 56 | [
"Galaxy clusters",
"Astronomical objects",
"Constellations",
"Aquarius (constellation)"
] |
57,813,648 | https://en.wikipedia.org/wiki/Niamh%20Shaw | Niamh Shaw is an Irish scientist, engineer, STEM communicator, writer, and performer.
Shaw was the 2019–2020 Honorary Ambassador for the Irish Girl Guides in recognition of the trail she has blazed for girls and women in Ireland. Her first book, Dream Big: An Irishwoman's Space Odyssey, published by Mercier Press tells the story of her 40-year quest to fulfill her childhood dream.
Early life and education
Shaw graduated from University College Dublin in 1990 with a Bachelor of Engineering in Mechanical Engineering, focusing on Biosystems Engineering, a Master in Biosystems Engineering in 1995, and Ph.D. in Food Science in 2001.
From 2001–2003 Shaw was a postdoctoral researcher in the Department of Food Science and Technology at University College Dublin.
In 2015, she participated in the International Space University Space Studies Programme.
Career
In 2003, Shaw began performing and acting. In 2007–2008 she appeared as Frances McGuigan in Fair City and as Mable Mills in the movie Dorothy Mills. She also appeared in Satellites & Meteorites (2008), A Shine of Rainbows (2009), Hideaways (2011), Little Brother, Big Trouble: A Christmas Adventure (2012), and You're Ugly Too (2015).
As an improvisation comedian, she has performed with The Craic Pack Comedy Improv, The Cardinals, Snatch Comedy, Cork, and The Second City, Los Angeles.
Science communicator
In 2011, Shaw created her first theatre show, "That's About the Size of It". During the show's making, she was invited by an arts initiative at CERN (Arts@CERN) to discuss her ideas about STEM and public engagement with particle physicists at the facility. The show toured from 2011 to 2013.
Other science-related shows include Baking in Space (2018–2019), Art in Mind (2016–2018), Irish Astronauts of 1991 (2018), My Place in Space (2014–2016), and Memory of Place (2015).
From 2014 to 2019, she was an artist in residence at Cork Institute of Technology BlackRock Castle Observatory.
Shaw is a co-founder of STEAMakers, a global initiative with her fellow SSP15 alumni, to create a global community and inspire the next generation to consider careers in STEM. She has presented scientific papers on the collaborative nature of her work between technology, science, and art. She is a regular speaker at STEM events to promote "Women in STEM" science outreach. In 2014, she participated in TEDxUCD (2014).
She has been contributing to the International Space University Space Studies Programme since 2016, as a lecturer in 2016, core lecture co-chair in 2017, and co-chair for the Humanities Department in 2018.
Since 2014, Shaw has set her life's mission to get to space as an artist and citizen rather than an astronaut.
In 2019, she travelled to NASA's Johnson Space Centre in Houston, Texas to speak at their annual Cross Industry Innovation Summit.
She joined the Homeward Bound (organization) for their 2023 expedition to Antarctica. In preparation for this, she developed an educational programme with the Environmental Awareness Office of Laois County Council for classrooms on climate change and the extreme environment of the Antarctic.
Speaker / lecturer
Shaw has spoken at conferences, summits, and TEDx events, including WIRED UK (Tate Modern, UK), New Scientist Live (Excel UK), and NASA Johnson Innovation Summit (Houston, Texas, USA).
On 9 March 2019, she spoke at Áras an Uachtarain, in response to President Higgin's "Women in STEM" speech at a special reception to celebrate International Women's Day.
Since completing the Space Studies Programme in 2015, she has been involved in lecturing on communications and arts content at the same programme in 2016, 2017, and 2018.
Performer / writer / artist
Shaw's theatre project, Diary of a Martian Beekeeper, premiered at Space week 2017, followed by a limited run in 2018. The show was funded under Science Foundation Ireland's 2017 Discover programme, working with ESA's Astronaut Centre to capture the massive group effort behind human space exploration.
Her second STEAM show, To Space concerned her dream to get to the International Space Station, sharing her mission with the astronaut crew on board. The show toured Europe and Australia between 2014–2016, including Edinburgh Fringe (2015), Adelaide Fringe (2016), Edinburgh International Science Festival (2016), and Cheltenham Science Festival (2016).
She has presented academic aspects of her work in STEAM at scientific conferences, including Communicating Astronomy with the Public (CAP) 2018, the International Astronautical Congress (2017, 2016), the European Geosciences Assembly (2015–2018), and European Planetary Sciences Congress (2015).
Shaw is a regular contributor to Irish radio and press on science and technology-related topics, and a regular writer for the BBC Sky at Night astronomy magazine.
Her other work in science art and technology and public engagement includes Memory of Place (Festival of Curiosity, 2016, 2015), "Dream Big" (International Space University, 2015), "Speaking with Plants" (University College Dublin Science Expression, 2014), That's About The Size Of It (Dublin City of Science, 2012; Dublin Fringe Festival, 2011), Boys of Foley Street (ANU Productions, Dublin Theatre Festival, 2012).
Her work has been supported by the European Space Agency (2015), Science Foundation Ireland (2014), The Arts Council of Ireland (2014, 2011), Arts@CERN (2011), Show in A Bag (2011), Dublin City Council Drama Bursary (2011).
Shaw is an alumna of MAKE (2011), The SPACE Programme (2011), The Festival of Curiosity Residency (2013), and The Robert Wilson Watermill International Spring Residency, New York (2010).
Analog Mars Missions
In 2017, she was part of Crew 173 in a simulated Mars mission at the Mars Desert Research Station in southern Utah as the artist and journalist for an international crew of six.
After MDRS-173, she experienced a zero-g flight at the Star City Yuri Gagarin Cosmonaut Training Center.
In 2018, she was an advisor and artist at a new analogue Mars facility, D-MARS, located in the Ramon Crater, Israel, and documented their first analog mission, D-MARS01.
Shaw has worked with Lottie Dolls to create a workshop for young girls, combining drama and space exploration. She has brought along Stargazer Lottie to her Mars Analog mission experiences, both in Utah and Israel, as well as bringing the doll to the zero-g flight in Russia.
Based on her Mars Analog experiences, Shaw joined with Sarah Baxter to create Shaw's third theater show, Diary of a Martian Beekeeper (2018).
Television, radio, and print
Shaw is a regular contributor on television and radio about science topics and her space adventures. She has appeared on The Tommy Tiernan Show, The Late Late Show, Today show on RTÉ One, and The Seven O'Clock Show on TV3. She has also contributed articles on a variety of space and science-related topics.
Honours and awards
In 2014, she was named one of Ireland's talented 38 Technology Women.
Shaw won a Science Foundation Ireland Outstanding Contribution to STEM Communication Award in 2018, sharing with Dr. John O'Donoghue of the Royal Society of Chemistry.
On International Women's Day 2019, at a special reception at Áras an Uachtaráin to celebrate Irish Women in STEM, she was invited to respond to Uachtaráin na hEireann, President Michael D. Higgins's speech. She is the 2019/2020 Honorary Ambassador to the Irish Girl Guides.
She was recognised by the European Space Agency as a European Space Champion in 2022 for her work in outstanding space advocacy.
References
External links
Let's start successfully failing Dr. Niamh Shaw at TEDxUCD
Living people
Science communicators
21st-century Irish actresses
Science bloggers
21st-century science writers
Women science writers
20th-century Irish scientists
21st-century Irish scientists
Irish women scientists
20th-century Irish women writers
21st-century Irish women writers
Irish television actresses
Irish film actresses
Alumni of University College Dublin
People associated with Cork Institute of Technology
Irish bloggers
Irish women bloggers
Year of birth missing (living people)
21st-century Irish engineers
21st-century Irish women engineers | Niamh Shaw | [
"Technology"
] | 1,721 | [
"Women science writers",
"Women in science and technology"
] |
57,813,841 | https://en.wikipedia.org/wiki/NGC%201278 | NGC 1278 is an elliptical galaxy located about 230 million light-years away in the constellation Perseus. NGC 1278 was discovered by astronomer Heinrich d'Arrest on February 14, 1863. It was then rediscovered by astronomer Guillaume Bigourdan on October 22, 1884 and was later listed as IC 1907. NGC 1278 is a member of the Perseus Cluster and is a low-luminosity AGN (LLAGN).
One supernova, SN 2016ajf (type Ia, mag. 16.9), was discovered in NGC 1278 on 18 February, 2016.
Globular clusters
Unlike the nearby galaxy NGC 1277 which has a dominant population of metal-rich or “red” globular clusters, NGC 1278 has a rich population of both metal-rich and metal-poor or “blue” globular clusters.
See also
List of NGC objects (1001–2000)
NGC 1275
NGC 1277
References
External links
Perseus Cluster
Perseus (constellation)
Elliptical galaxies
Active galaxies
1278
012438
02670
Astronomical objects discovered in 1863
IC objects | NGC 1278 | [
"Astronomy"
] | 228 | [
"Perseus (constellation)",
"Constellations"
] |
57,814,051 | https://en.wikipedia.org/wiki/NGC%201279 | NGC 1279 is a lenticular galaxy estimated to be 324 million light-years away from the Milky Way in the constellation Perseus. It has diameter of about 110,000 ly, and is a member of the Perseus Cluster.
It was discovered on December 12, 1876, by astronomer John Louis Emil Dreyer.
References
External links
Perseus (constellation)
Lenticular galaxies
Perseus Cluster
1279
12448
Astronomical objects discovered in 1876 | NGC 1279 | [
"Astronomy"
] | 94 | [
"Perseus (constellation)",
"Constellations"
] |
57,814,827 | https://en.wikipedia.org/wiki/STS%20Lord%20Nelson | STS Lord Nelson was a sail training ship operated by the Jubilee Sailing Trust. She was designed by Colin Mudie and launched on 17 October 1986.
The ship was built by the Jubilee Sailing Trust (JST) and, along with the SV Tenacious, the pair were the only tall ships in the world that are wheelchair accessible throughout. The JST are an international UN accredited charity offering sailing adventures to people of all abilities and backgrounds. She was decommissioned in October 2019.
Design and construction
STS Lord Nelson was commissioned by the Jubilee Sailing Trust, and the build was started in the summer of 1984 at the yard of James W Cook, Wivenhoe, Essex. She was designed by Colin Mudie, and is his design no 342. The ship was launched almost a year after the formal keel laying. After J W Cook went into voluntary liquidation, Lord Nelson was moved to Vosper Thornycroft's yard in Woolston, Southampton. As a result of an industrial dispute at Vospers, Lord Nelson had to move again, this time to Coles Yard in Cowes where the remainder of the work was carried out. She was finally sailed in completed form from Southampton on 17 October 1986.
In service
STS Lord Nelson completed 16,000 accessible voyages during her 33 years at sea with the Jubilee Sailing Trust.
She finished her final voyage on 10 October 2019 to Southampton, and was subsequently moved to Bristol docks for decommissioning.
Disposal
On the 26 April 2021 the Jubilee Sailing Trust announced that they would sell the vessel, by then in a state of significant disrepair. No sale of Lord Nelson was concluded and in August 2022, the ship's owning company, Jubilee Sailing Trust Ltd, was put into administration. With still no sale, the administrators put the ship for auction in June 2023.
References
Further reading
Report on the investigation of Lord Nelson contact with Tower Bridge London River Thames 15 May 2004 assets.publishing.service.gov.uk, Retrieved 2018-12-07
Harry Turner: World's first round-the-world ship crewed by disabled docks in London yachtsandyachting.com, 24 Sep 2014, Retrieved 2018-12-07
1986 ships
Accessible transportation
Disabled boating
Tall ships of the United Kingdom
Individual sailing vessels
Barques
Sail training ships | STS Lord Nelson | [
"Physics"
] | 460 | [
"Physical systems",
"Transport",
"Accessible transportation"
] |
57,816,166 | https://en.wikipedia.org/wiki/WDR%20paper%20computer | The WDR paper computer or Know-how Computer is an educational model of a computer consisting only of a pen, a sheet of paper, and individual matches in the most simple case. This allows anyone interested to learn how to program without having an electronic computer at their disposal.
The paper computer was created in the early 1980s when computer access was not yet widespread in Germany, to allow people to familiarize themselves with basic computer operation and assembly-like programming languages. It was distributed in over copies and at its time belonged to the computers with the widest circulation.
The Know-how Computer was developed by and Ulrich Rohde and was first presented in the television program WDR Computerclub (broadcast by Westdeutscher Rundfunk) in 1983. It was also published in German computer magazines mc and .
The original printed version of the paper computer has up to 21 lines of code on the left and eight registers on the right, which are represented as boxes that contain as many matches as the value in the corresponding register. A pen is used to indicate the line of code which is about to be executed. The user steps through the program, adding and subtracting matches from the appropriate registers and following program flow until the stop instruction is encountered.
The instruction set of five commands is small but Turing complete and therefore enough to represent all mathematical functions:
inc *register*: Add 1 to the register.
dec *register*: Subtract 1 from the register.
jmp *line*: Jumps to the specified line.
isz *register*: Checks if the register is zero. If so, skips a line. If not, continues normally.
stp: Stops the program.
In the original newspaper article about this computer, it was written slightly differently (translation):
+ = Add 1 to the contents of data register XX and increase (program step) by 1
- = Subtract 1 from the contents of data register XX and increase (program step) by 1
(J) = (Jump) to (line) XX
0 = Check if the content of the data register XX is equal to 0. If so, then increase (program step) by 2; if no(t), then increase (program step) by 1
Stop = Stop
An emulator for Windows is available on Wolfgang Back's website, but a JavaScript emulator also exists. Emulators place fewer restrictions on line count or the number of registers, allowing longer and more complex programs.
The paper computer's method of operation is nominally based on a register machine by Elmar Cohors-Fresenborg, but follows more the approach of John Cedric Shepherdson and Howard E. Sturgis in their Shepherdson–Sturgis register machine model.
A derived version of the paper computer is used as a "Know-How Computer" in Namibian school education.
See also
Digi-Comp I
Digi-Comp II
Geniac
CARDboard Illustrative Aid to Computation
Turing Tumble
Little man computer
References
Further reading
(NB. Javascript implementation of a paper computer)
Computers
German inventions
1983 in computing
Models of computation
Educational abstract machines
Educational programming languages | WDR paper computer | [
"Technology"
] | 640 | [
"Computers"
] |
57,817,425 | https://en.wikipedia.org/wiki/Matthew%20Davis%20%28physicist%29 | Matthew Davis is a New Zealand/Australian physicist, and is head of Physics at the University of Queensland, Australia.
He is known for his work on the dynamics of vortices and superfluidity in Bose–Einstein condensates, particularly at finite temperatures.
Expertise
Nonequilibrium dynamics, superfluidity, turbulence and vortices in Bose–Einstein condensates
Dynamics of phase transitions and formation of topological defects
Relaxation and thermodynamics of isolated quantum systems
Generation of non-classical correlations and entanglement
Computational methods for quantum systems.
Career
Davis received a BSc(Hons) from the University of Otago in New Zealand in 1997 and a D.Phil. (in atomic and laser physics) from the University of Oxford in the United Kingdom in 2001.
Davis was an EPSRC Postdoctoral Research Fellow in Theoretical Physics at the University of Oxford in the UK 2001, a UQ Postdoctoral Research Fellow in the School of Mathematics and Physics at the University of Queensland in Australia 2002, became a lecturer at UQ in 2003, Senior Lecturer in 2005, Associate Professor in 2009, Professor of Theoretical Physics in 2013, and Head of Physics at UQ in 2017.
Davis is a Chief Investigator within the ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET) investigating novel nonequilibrium states of matter.
He is also a Chief Investigator within the ARC Centre for Engineered Quantum Systems (EQUS), studying the quantum behaviour of ultra-cold gases and Bose–Einstein condensation.
Publications
As of September 2018, Davis has co-edited one book, authored five book chapters, and published 75 journal articles, 24 conference papers, and one other publication.
Davis currently has a career h-index of 31 (31 publications with more than 31 citations), and his papers have attracted 2989 citations in total, averaging almost 40 citations per article, and with more than 1000 citations in the last four years.
Selected publications
Observation of vortex dipoles in an oblate Bose–Einstein condensate, Physical Review Letters, 2010. [210 citations] First observation and experimental and theoretical study of multi-core vortex dipoles in a Bose-Einstein condensation – the fundamental localized excitation carrying momentum in a superfluid.
Dynamics and statistical mechanics of ultra-cold Bose gases using c-field techniques. Advances in Physics, 2008 [239 citations] Invited review describing the c-field method and its application. Persuaded many researchers to make use of this method, and is becoming a standard reference.
Spontaneous vortices in the formation of Bose–Einstein condensates. Nature, 2008 [273 citations] The first observation and understanding via theoretical simulation of spontaneous rotation of a BEC formed from the cooling of a Bose gas.
Recognition
2018: Divisional Associate Editor, Physical Review Letters
2016: Editorial Fellow, SciPost Physics
2016: Fellow of the American Institute of Physics
2015: JILA Visiting Fellow, University of Colorado
2015: American Physical Society Outstanding Referee.
2012: Australian Learning and Teaching Council Citation for Outstanding Contribution to Student Learning.
2011: Queensland Tall Poppy Award.
2011: University of Queensland Citation for Outstanding Contribution to Student Learning.
2010: Australian Research Council Queen Elizabeth II Fellowship.
2007: University of Queensland Foundation Research Excellence Award.
2007: EPSA Faculty Teaching Excellence Award.
2002: University of Queensland Postdoctoral Research Fellowship.
2001: EPSRC Fellowship in Theoretical Physics, University of Oxford
1998: North Senior Scholarship, St John's College, University of Oxford
1997: Commonwealth Scholarship, University of Oxford
References
Living people
Quantum physicists
Academic staff of the University of Queensland
University of Otago alumni
Year of birth missing (living people)
20th-century New Zealand physicists
21st-century Australian physicists
Alumni of the University of Oxford
Fellows of the American Physical Society | Matthew Davis (physicist) | [
"Physics"
] | 760 | [
"Quantum physicists",
"Quantum mechanics"
] |
57,817,972 | https://en.wikipedia.org/wiki/ADA%20%28smart%20antenna%29 | ADA (an abbreviation of adaptive antenna) is an advanced smart antenna, using multichannel controlled reception pattern antenna (CRPA), designed for various platforms, including UAVs, planes and ships, manufactured by the MLM factory of the Israeli Aerospace Industries (IAI).
The ADA enables vehicles, missiles and other platforms equipped with the smart antenna to navigate even when heavy jamming is conducted in order to block all reception of GPS and other GNSS signals. Using advanced techniques even very faint "good" signals are being extracted from the superposition of incoming waves that include noise and strong signals produced by the enemy (or friendly) jammers. These signals are then used (just like a regular GPS receiver) to triangulate the position and determine the GPS tune.
History
The theory of the ADA started to emerge as a theory of multichannel estimation. Its origins go back into methods developed in the 1920s that were used to determine direction of the arrival of radio signals by a set of two antennas based on the phase difference or amplitudes of their output voltages. Thus, the assessment of the directions of arrival of a single signal was conducted according to pointed type indicator readings or according to the Lissajous curves,
drawn by beam on the oscilloscope screen.
The existence of ADA was publicly unveiled in February 2017, along with a report that the Israeli Defence Forces has already decided to install the ADAs on "major platforms" in service. It was also displayed in the Aero India air show that was held from 14th to the 18th that month in Bangalore.
In July 2017 MLM has signed a contract with American Honeywell to jointly develop a GPS anti-jam navigation system, based on ADA and Honywell's devices.
References
External links
IAI ADA, by the IAI, on YouTube
IAI, Honeywell to jointly develop anti-jam system, by Globes, May 2018
IAI Unveils ADA-O to Help Land Platforms Deal with GNSS Anti-Jammers, by Israel Defense, Mar 2019
Radio frequency antenna types
Smart devices
MLM products
Military equipment | ADA (smart antenna) | [
"Technology"
] | 423 | [
"Home automation",
"Smart devices"
] |
57,818,400 | https://en.wikipedia.org/wiki/EASN%20Association | The European Aeronautics Science Network (EASN) is an international non-profit association dedicated to the advancement of the European aeronautics sciences and technologies. The establishment of EASN goes back to 2002 and it was based on two subsequent support actions funded by the European Commission while it was founded as an open, self-funded and self sustainable association in 2008. Specifically, the EASN Association is the Association of the European Academia active in supporting aviation research, facing the fragmentation of Academia and disseminating the new knowledge and breakthrough technologies incubated through aviation research. Headquartered in Brussels, Belgium, the EASN Association encounters members across 28 European countries with the number constantly increasing.
Overview
On 6 May 2008 the EASN Association was officially established by 22 distinguished personalities of the European Aeronautics research community, with the encouragement of the European Commission and the support of several university professors throughout Europe. The mission of the Association is to contribute to the advancement of the aeronautics sciences and technologies and support the education and research in Europe. The tools for accomplishing the above objectives include among others the organization of scientific events, research forums and collaboration with other networks and associations.
In 2017, the Association counted approximately 350 effective members Europe-wide. These effective members are individuals mainly from European universities active in aviation research. Furthermore, the Association has a number of about 50 associate members which are highly-ranked entities, such as Universities, University Departments, Research Establishments, SMEs, Industries and Laboratories. Among the Association’s associate members top universities are included such as KU Leuven, Polytechnic University of Milan, Warsaw University of Technology, University of Stuttgart, Politecnico di Torino, RWTH Aachen University etc., Research Establishments such as the German Aerospace Center (DLR), Italian Aerospace Research Centre (CIRA), Office National d'Etudes et de Recherches Aérospatiales (ONERA) etc. and European manufacturers such as Airbus.
Furthermore, the Association is connected with 15.000 researchers across 28 European countries while has strong links with other networks.
References
External links
EASN Association Website https://www.easn.net/
Aeronautics organizations
European Group
European Union and science and technology
Engineering university associations and consortia
Higher education organisations based in Europe
Science and technology in Europe | EASN Association | [
"Engineering"
] | 461 | [
"Aerospace engineering",
"Aerospace engineering organizations",
"Aeronautics organizations"
] |
57,819,446 | https://en.wikipedia.org/wiki/K2-236b | K2-236b is a Neptune-like exoplanet that orbits an F-type star. It is also called EPIC 211945201 b. Its mass is 27 Earths, it takes 19.5 days to complete one orbit of its star, and is 0.148 AU from its star. Its discovery was announced in 2018. This was the first exoplanet discovered by scientists based in India. The discoverers were Abhijit Chakraborty (PRL), Arpita Roy (Caltech), Rishikesh Sharma (PRL), Suvrath Mahadevan (Penn State), Priyanka Chaturvedi (Thüringer Landessternwarte Tautenburg), Neelam J. S. S. V. Prasad (PRL), and B. G. Anandarao (PRL).
Overview
The exoplanet K2-236b was discovered in 2018 using the transit method. Using this method, astronomers can photometrically analyze the atmospheric composition of other planets, detecting compounds such as methane and water vapor. It is the only planet orbiting around EPIC 211945201, a G0 class star, situated in the constellation of Cancer at a distance of 596 light-years from the Sun. Its host star is aged 4 billion years. K2-236b orbits its star in about 19 terrestrial days. It orbits closer to the star than the internal limit of the habitable zone. It has a low density and may be composed of gas.
Discovery
K2-236b was found to be a planetary candidate from K2 photometry in Campaigns 5 & 16. The exoplanet transits the bright star (Vmag = 10.15, G0 spectral type) in a 19.492 day orbit. The photometric data combined with false positive probability calculations using VESPA may not be sufficient to confirm the planetary scenario, but high-resolution spectroscopic are taken using the PARAS spectrograph (19 radial velocity observations) over a time-baseline of 420 days.
The data shows that the planet has a radius of 6.12 ± 0.1 and a mass of . It consists of a density of g/cm3. Based on the mass and radius, it is estimated that the heavy element content is 60-70 % of the total mass. The surface temperature of the planet was found to be around , as it is very close to the host star. It is seven times nearer to its star, in comparison with Earth-Sun distance. This shows that the extra-solar planet is in the uninhabitable zone. The discovery is of importance for understanding the formation mechanism of such super-Neptune or sub-Saturn planets that are too close to the host star, according to scientists.
See also
List of exoplanet firsts
List of exoplanetary host stars
List of exoplanets discovered using the Kepler spacecraft
List of planets observed during Kepler's K2 mission
References
Transiting exoplanets
Exoplanets discovered by K2
Exoplanets discovered in 2018
Cancer (constellation) | K2-236b | [
"Astronomy"
] | 645 | [
"Cancer (constellation)",
"Constellations"
] |
57,820,194 | https://en.wikipedia.org/wiki/NGTS-3Ab | NGTS-3Ab is a gas giant exoplanet that orbits a G-type star. Its mass is 2.38 Jupiters, it takes 1.7 days to complete one orbit of its star, and is 0.023 AU from its star. Its discovery was announced in 2018. The Jupiter-like planet is discovered by 39 astronomers, mainly Max Günther, Didier Queloz, Edward Gillen, Laetitia Delrez, and Francois Bouchy.
Overview
NGTS-3Ab was discovered in 2018 by the use of transit method. It is the only planet orbiting around NGTS-3A, a G6V class star, situated in the constellation of Columba in 2480 light years from the Sun. The exoplanet orbits its star in about 2 terrestrial days. The orbit is closer to the star than the internal limit of the habitable zone. It has a low density and can be composed of gas. It has a low Earth similarity index (0.06) and should be very different from our planet.
Discovery
The discovery of NGTS-3Ab, a hot Jupiter found orbiting a star in a still visually unresolved binary system, was announced in June 2018. The data regarding the exoplanet is based on the data gathered with the Next Generation Transit Survey (NGTS), SPECULOOS, and HARPS, and enhanced by recent advances with the centroiding technique for NGTS.
The planetary system NGTS-3A was detected by a conjointly model multi-colour photometry, centroids and radial velocity (RV) extraction process. RV cross-correlation functions (CCFs) and study correlations of the bisector inverse span (BIS) are simulated in order to define the characteristics of the exoplanet NGTS-3Ab.
See also
NGTS-3
List of exoplanet firsts
List of exoplanetary host stars
List of exoplanets discovered using the Kepler spacecraft
List of planets observed during Kepler's K2 mission
References
Further reading
"NGTS-3Ab". exoplanetarchive.ipac.caltech.edu.
"The Extrasolar Planet Encyclopaedia — NGTS-3Ab". exoplanet.eu.
Transiting exoplanets
Exoplanets discovered in 2018
Columba (constellation)
Hot Jupiters | NGTS-3Ab | [
"Astronomy"
] | 495 | [
"Columba (constellation)",
"Constellations"
] |
44,463,312 | https://en.wikipedia.org/wiki/Clark%20CA1 | The Clark air Crawler model CA-1 widely known as the Clark CA-1 was a small airborne bulldozer designed for improvement of runways in World War II by the United States Armed Forces.
Design and production
In 1942, the United States military created a new engineering unit that would be extremely mobile; this could only be done with light equipment. The military began looking for new bulldozer small and light enough to be flown in the Douglas C-47 and the Waco CG-4A. When the parameters were set the military looked for a company to create such a machine. They were to draw inspiration from the US Forestry Service's "trail tractor" (a small tractor for use in small clearings and fields within the forest).
In 1942, the Clark Machine Company took the contract. Clark initially built 14 operational dozers and conducted extensive tests at their facilities. Once proven, the military ordered 800 more and eventually extended that figure. The War Department worked with Clark Machine over the course of the years 1942 and 1943 ordering many CA-1s by the end of World War 2. It is estimated that there were more than 2,500 produced.
Operation
The Tractor was flown in by either a C-46 or C-47 or transported by a glider, which landed on an unimproved runway or a possible runway. Once dropped off, the engineers used the tractors to construct a paved or improved landing strip. The CA-1 would be used predominantly to tow graders and pan scrapers. This style of construction was fast and relatively efficient which gave the United States a reasonable strategic advantage in the Pacific campaign of World War 2 due to the island hopping tactic that required many new airfields. After the war a new community of people eager to restore these small and light tractor emerged.
More than 1,500 CA-1s were used by the US Army.
Survivors
A Clark Ca1 was restored to running condition in New Zealand in 2023.
The Air Mobility Command Museum in Dover, Delaware has a fully functional Clark Airborne CA1 tractor on display. This specimen was restored Mr. Darrell Smoker
The National Museum of the United States Airforce has one on display which was restored by the Clark Equipment Co.
References
7. https://www.youtube.com/watch?v=-D9g0dbBLZE&list=PL1YKtKk1JpRdAhRFeEdPGPzaYovZeEYT0
External links
Relevant conversations
http://www.questmasters.us/Clark_CA-1.html
Tractors | Clark CA1 | [
"Engineering"
] | 517 | [
"Engineering vehicles",
"Tractors",
"Bulldozers"
] |
44,464,978 | https://en.wikipedia.org/wiki/Regeneration%20in%20humans | Regeneration in humans is the regrowth of lost tissues or organs in response to injury. This is in contrast to wound healing, or partial regeneration, which involves closing up the injury site with some gradation of scar tissue. Some tissues such as skin, the vas deferens, and large organs including the liver can regrow quite readily, while others have been thought to have little or no capacity for regeneration following an injury.
Numerous tissues and organs have been induced to regenerate. Bladders have been 3D-printed in the lab since 1999. Skin tissue can be regenerated in vivo or in vitro. Other organs and body parts that have been procured to regenerate include: penis, fats, vagina, brain tissue, thymus, and a scaled down human heart. One goal of scientists is to induce full regeneration in more human organs.
There are various techniques that can induce regeneration. By 2016, regeneration of tissue had been induced and operationalized by science. There are four main techniques: regeneration by instrument; regeneration by materials; regeneration by drugs and regeneration by in vitro 3D printing.
History of human tissue
In humans with non-injured tissues, the tissue naturally regenerates over time; by default, new available cells replace expended cells. For example, the body regenerates a full bone within ten years, while non-injured skin tissue is regenerated within two weeks. With injured tissue, the body usually has a different response. This emergency response usually involves building a degree of scar tissue over a time period longer than a regenerative response, as has been proven clinically and via observation. There are many more historical and nuanced understandings about regeneration processes. In full thickness wounds that are under 2mm, regeneration generally occurs before scarring. In 2008, in full thickness wounds over 3mm, it was found that a wound needed inserted in order to induce full tissue regeneration.
Whereas 3rd degree burns heal slowly by scarring, in 2016 it was known that full thickness fractional photothermolysis holes heal without scarring. Up to 40% of full thickness skin can be removed without scarring in an area, in a fractional pattern via coring of tissue.
Some human organs and tissues regenerate rather than simply scar, as a result of injury. These include the liver, fingertips, and endometrium. More information is now known regarding the passive replacement of tissues in the human body, as well as the mechanics of stem cells. Advances in research have enabled the induced regeneration of many more tissues and organs than previously thought possible. The aim for these techniques is to use these techniques in the near future for the purpose of regenerating any tissue type in the human body.
Regeneration techniques
By 2016, regeneration had been operationalised and induced by four main techniques: regeneration by instrument; regeneration by materials; regeneration by 3D printing; and regeneration by drugs. By 2016, regeneration by instrument, regeneration by materials and by regeneration drugs had been generally operationalised in vivo (inside living tissues). Whilst by 2016, regeneration by 3D printing had been generally operationalised by in vitro (inside the lab) in order to be built and prepare tissue for transplantation.
By instrument
A cut by a knife or a scalpel generally scars, though a piercing by a needle does not. In 1976, a 3 by 3 cm scar on a non-diabetic was regenerated by insulin injections and the researchers, highlighting earlier research, argued that the insulin was regenerating the tissue. The anecdotal evidence also highlighted that a syringe was one of two variables that helped bring regeneration of the arm scar. The syringe was injected into the four quadrants three times a day for eighty-two days. After eighty-two days, after many consecutive injections, the scar was resolved and it was noted no scar was observable by the human eye. After seven months the area was checked again and it was once again noted that no scar could be seen.
In 1997, it was proven that wounds created with an instrument that are under 2mm can heal scar free, but larger wounds that are larger than 2mm healed with a scar.
In 2013, it was proven in pig tissue that full thickness micro columns of tissue, less than 0.5mm in diameter could be removed and that the replacement tissue, was regenerative tissue, not scar. The tissue was removed in a fractional pattern, with over 40% of a square area removed; and all of the fractional full thickness holes in the square area healed without scarring. In 2016 this fractional pattern technique was also proven in human tissue. In 2021, more people were paying attention to the possibility of scar free healing alongside new technologies involving instruments.
With materials
Generally, humans can regenerate injured tissues in vivo for limited distances of up to 2mm. The further the wound distance is from 2mm the more the wound regeneration will need inducement. By 2009, via the use of materials, a max induced regeneration could be achieved inside a 1 cm tissue rupture. Bridging the wound, the material allowed cells to cross the wound gap; the material then degraded. This technology was first used inside a broken urethra in 1996. In 2012, using materials, a full urethra was restored in vivo.
Macrophage polarization is a strategy for skin regeneration. Macrophages are differentiated from circulating monocytes. Macrophages display a range of phenotypes varying from the M1, pro-inflammatory type to the M2, pro-regenerative type. Material hydrogels polarise macrophages into the key M2 regenerative phenotype in vitro. In 2017, hydrogels provided full regeneration of skin, with hair follicles, after partial excision of scars in pigs and after full thickness wound incisions in pigs.
By 3D printing
In 2009, the regeneration of hollow organs and tissues with a long diffusion distance, was a little more challenging. Therefore, to regenerate hollow organs and tissues with a long diffusion distance, the tissue had to be regenerated inside the lab, via the use of a 3D printer.
Various tissues that have been regenerated by in vitro 3D printing include:
The first organ ever induced and made in the lab was the bladder, which was created in 1999.
By 2014, there had been various tissues regenerated by the 3D printer and these tissues included: muscle, vagina, penis and the thymus.
In 2014, a conceptual human lung was first bioengineered in the lab. In 2015, the lab robustly tested its technique and regenerated a pig lung. The pig lung was then successfully transplanted into a pig without the use of immunosuppressive drugs.
In 2015, researchers developed a proof of principle biolimb inside a laboratory; they also estimated that it would be at least a decade for any testing of limbs in humans. The limb demonstrated fully functioning skin, muscles, blood vessels and bones.
In April 2019, researchers 3D printed a human heart. The prototype heart was made by human stem cells but only to the size of a rabbit's heart. In 2019, the researchers hoped to one day place a scaled up version of the heart inside humans.
Gradations of complexity
With printing tissues, by 2012, there were four accepted standard levels of regenerative complexity that were acknowledged in various academic institutions:
Level one, flat tissue like skin was the simplest to recreate;
Level two was tubular structures such as blood vessels;
Level three was hollow non-tubular structures;
Level four was solid organs, which were by far the most complex to recreate due to the vascularity.
In 2012, within 60 days it was possible, inside the lab, to grow tissue the size of half a postage stamp to the size of a football field. Most cell types could be grown and expanded outside of the body, with the exception of the liver, nerve and pancreas, as these tissue types need stem cell populations.
With drugs
Lipoatrophy is the localised loss of fat in tissue. It is common in diabetics who use conventional insulin injection treatment. In 1949, a much more pure form of insulin was, instead of causing lipoatrophy, shown to regenerate the localised loss of fat after injections in to diabetics. In 1984, it was shown that different insulin injections have different regenerative responses with regards to creating skin fats in the same person. It was shown in the same body that conventional forms of insulin injections cause lipoatrophy and highly purified insulin injections cause lipohypertrophy. In 1976, the regenerative response was shown to work in a non-diabetic after a 3 x 3 cm lipoatrophic arm scar was treated with pure monocomponent porcine soluble insulin. A syringe injected insulin under the skin equally in the four quadrants of the defect. To layer four units of insulin evenly into the base of the defect, each quadrant of the defect received one unit of insulin three times a day, for eighty-two days. After eighty-two days of consecutive injections the defect regenerated to normal tissue.
In 2016, scientists could transform a skin cell into any other tissue type via the use of drugs.
The technique was noted as safer than genetic reprogramming which, in 2016, was a concern medically. The technique, used a cocktail of chemicals and enabled efficient on site regeneration without any genetic programming. In 2016, it was hoped to one day use this drug to regenerate tissue at the site of tissue injury. In 2017, scientists could turn many cell types (such as brain and heart) into skin.
Research
Scientists found leprosy-causing bacteria viably regenerate and rejuvenate the liver in its armadillos hosts, which may enable novel human therapies based on knowledge or components gained from naturally evolved organisms or capabilities.
Naturally regenerating appendages and organs
Heart
Cardiomyocyte necrosis activates an inflammatory response that serves to clear the injured myocardium from dead cells, and stimulates repair, but may also extend injury. Research suggests that the cell types involved in the process play an important role. Namely monocyte-derived macrophages tend to induce inflammation while inhibiting cardiac regeneration, while tissue resident macrophages may help restoration of tissue structure and function.
Endometrium
The endometrium after the process of breakdown via the menstruation cycle, re-epithelializes swiftly and regenerates. Though tissues with a non-interrupted morphology, like non-injured soft tissue, completely regenerate consistently; the endometrium is the only human tissue that completely regenerates consistently after a disruption and interruption of the morphology. The inner lining of the uterus is the only adult tissue to undergo rapid cyclic shedding and regeneration without scarring, shedding and restoring roughly inside a 7-day window on a monthly basis. All other adult tissues, upon rapid shedding or injury, can scar.
Fingers
In May 1932, L. H. McKim published a report describing the regeneration of an adult digit-tip following amputation. A house surgeon in the Montreal General Hospital underwent amputation of the distal phalanx to stop the spread of an infection. In less than one month following surgery, x-ray analysis showed the regrowth of bone while macroscopic observation showed the regrowth of nail and skin. This is one of the earliest recorded examples of adult human digit-tip regeneration.
Studies in the 1970s showed that children up to the age of 10 or so who lose fingertips in accidents can regrow the tip of the digit within a month provided their wounds are not sealed up with flaps of skin – the de facto treatment in such emergencies. They normally will not have a fingerprint, and if there is any piece of the finger nail left it will grow back as well, usually in a square shape rather than round.
In August 2005, Lee Spievack, then in his early sixties, accidentally sliced off the tip of his right middle finger just above the first phalanx. His brother, Dr. Alan Spievack, was researching regeneration and provided him with powdered extracellular matrix, developed by Dr. Stephen Badylak of the McGowan Institute of Regenerative Medicine. Mr. Spievack covered the wound with the powder, and the tip of his finger re-grew in four weeks. The news was released in 2007. Ben Goldacre has described this as "the missing finger that never was", claiming that fingertips regrow and quoted Simon Kay, professor of hand surgery at the University of Leeds, who from the picture provided by Goldacre described the case as seemingly "an ordinary fingertip injury with quite unremarkable healing"
A similar story was reported by CNN. A woman named Deepa Kulkarni lost the tip of her little finger and was initially told by doctors that nothing could be done. Her personal research and consultation with several specialists including Badylak eventually resulted in her undergoing regenerative therapy and regaining her fingertip.
Kidney
Regenerative capacity of the kidney has been recently explored.
The basic functional and structural unit of the kidney is nephron, which is mainly composed of four components: the glomerulus, tubules, the collecting duct and peritubular capillaries. The regenerative capacity of the mammalian kidney is limited compared to that of lower vertebrates.
In the mammalian kidney, the regeneration of the tubular component following an acute injury is well known. Recently regeneration of the glomerulus has also been documented. Following an acute injury, the proximal tubule is damaged more, and the injured epithelial cells slough off the basement membrane of the nephron. The surviving epithelial cells, however, undergo migration, dedifferentiation, proliferation, and redifferentiation to replenish the epithelial lining of the proximal tubule after injury. Recently, the presence and participation of kidney stem cells in the tubular regeneration has been shown. However, the concept of kidney stem cells is currently emerging. In addition to the surviving tubular epithelial cells and kidney stem cells, the bone marrow stem cells have also been shown to participate in regeneration of the proximal tubule, however, the mechanisms remain controversial. Studies examining the capacity of bone marrow stem cells to differentiate into renal cells are emerging.
Like other organs, the kidney is also known to regenerate completely in lower vertebrates such as fish. Some of the known fish that show remarkable capacity of kidney regeneration are goldfish, skates, rays, and sharks. In these fish, the entire nephron regenerates following injury or partial removal of the kidney.
Liver
The human liver is particularly known for its ability to regenerate, and is capable of doing so from only one quarter of its tissue, due chiefly to the unipotency of hepatocytes. Resection of liver can induce the proliferation of the remaining hepatocytes until the lost mass is restored, where the intensity of the liver's response is directly proportional to the mass resected. For almost 80 years surgical resection of the liver in rodents has been a very useful model to the study of cell proliferation.
Toes
Toes damaged by gangrene and burns in older people can also regrow with the nail and toe print returning after medical treatment for gangrene.
Vas deferens
The vas deferens can grow back together after a vasectomy–thus resulting in vasectomy failure. This occurs due to the fact that the epithelium of the vas deferens, similar to the epithelium of some other human body parts, is capable of regenerating and creating a new tube in the event that the vas deferens is damaged and/or severed. Even when as much as five centimeters, or two inches, of the vas deferens is removed, the vas deferens can still grow back together and become reattached–thus allowing sperm to once again pass and flow through the vas deferens, restoring one's fertility.
Induced regeneration
There are several human tissues that have been successfully or partially induced to regenerate. Many fall under the topic of regenerative medicine, which includes the methods and research conducted with the aim of regenerating the organs and tissues of humans as a result of injury. The major strategies of regenerative medicine include dedifferentiating injury site cells, transplanting stem cells, implanting lab-grown tissues and organs, and implanting bioartificial tissues.
Bladder
In 1999, the bladder was the first regenerated organ to be given to seven patients; as of 2014, these regenerated bladders are still functioning inside the beneficiaries.
Fat
In 1949, purified insulin was shown to regenerate fat in diabetics with lipoatrophy. In 1976, after 82 days of consecutive injections into a scar, purified insulin was shown to safely regenerate fat and completely regenerate skin in a non-diabetic.
During a high-fat diet, and during hair follicle growth, mature adipocytes (fats) are naturally formed in multiple tissues. Fat tissue has been implicated in the inducement of tissue regeneration. Myofibroblasts are the fibroblast responsible for scar and in 2017 it was found that the regeneration of fat transformed myofibroblasts into adipocytes instead of scar tissue. Scientists also identified bone morphogenetic protein (BMP) signalling as important for myofibroblasts transforming into adipocytes for the purpose of skin and fat regeneration.
Heart
Cardiovascular diseases are the leading cause of death worldwide, and have increased proportionally from 25.8% of global deaths in 1990, to 31.5% of deaths in 2013. This is true in all areas of the world except Africa.
In addition, during a typical myocardial infarction or heart attack, an estimated one billion cardiac cells are lost.
The scarring that results is then responsible for greatly increasing the risk of life-threatening abnormal heart rhythms or arrhythmias. Therefore, the ability to naturally regenerate the heart would have an enormous impact on modern healthcare. However, while several animals can regenerate heart damage (e.g. the axolotl), mammalian cardiomyocytes (heart muscle cells) cannot proliferate (multiply) and heart damage causes scarring and fibrosis.
Despite the earlier belief that human cardiomyocytes are not generated later in life, a recent study has found that this is not the case. This study took advantage of the nuclear bomb testing and other radioactive sources during the Atomic Age which introduced carbon-14 into the atmosphere (essentially all of which had decayed up to that point in Earth's history) and therefore into the cells of biologically active inhabitants. They extracted DNA from the myocardium of these research subjects and found that cardiomyocytes do in fact renew at a slowing rate of 1% per year from the age of 25, to 0.45% per year at the age of 75 by comparing the presence of carbon-14 with the stable and abundant carbon-12. This amounts to less than half of the original cardiomyocytes being replaced during the average lifespan. However, serious doubts have been placed on the validity of this research, including the appropriateness of the samples as representative of normally aging hearts.
Further research has been conducted that supports the potential for human cardiac regeneration. Inhibition of p38 MAP kinase was found to induce mitosis in adult mammalian cardiomyocytes, while treatment with FGF1 and p38 MAP kinase inhibitors was found to regenerate the heart, reduce scarring, and improve cardiac function in rats with cardiac injury.
One of the most promising sources of heart regeneration is the use of stem cells. It was demonstrated in mice that there is a resident population of stem cells or cardiac progenitors in the adult heart – this population of stem cells was shown to be reprogrammed to differentiate into cardiomyocytes that replaced those lost during a heart tissue death. In humans specifically, a "cardiac mesenchymal feeder layer" was found in the myocardium that renewed the cells with progenitors that differentiated into mature cardiac cells. What these studies show is that the human heart contains stem cells that could potentially be induced into regenerating the heart when needed, rather than just being used to replace expended cells.
Loss of the myocardium due to disease often leads to heart failure; therefore, it would be useful to be able to take cells from elsewhere in the heart to replenish those lost. This was achieved in 2010 when mature cardiac fibroblasts were reprogrammed directly into cardiomyocyte-like cells. This was done using three transcription factors: GATA4, Mef2c, and Tbx5.
Cardiac fibroblasts make up more than half of all heart cells and are usually not able to conduct contractions (are not cardiogenic), but those reprogrammed were able to contract spontaneously. The significance is that fibroblasts from the damaged heart or from elsewhere, may be a source of functional cardiomyocytes for regeneration.
Simply injecting functioning cardiac cells into a damaged heart is only partially effective. In order to achieve more reliable results, structures composed of the cells need to be produced and then transplanted. Masumoto and his team designed a method of producing sheets of cardiomyocytes and vascular cells from human iPSCs. These sheets were then transplanted onto infarcted hearts of rats, leading to significantly improved cardiac function. These sheets were still found to be present four weeks later. Research has also been conducted into the engineering of heart valves. Tissue-engineered heart valves derived from human cells have been created in vitro and transplanted into a non-human primate model. These showed a promising amount of cellular repopulation even after eight weeks, and succeeded in outperforming currently-used non-biological valves. In 2021, researchers demonstrated a switchable iPSCs-reprogramming-based approach for regeneration of damaged heart without tumor-formation in mice. In April 2019, researchers 3D printed a prototype human heart the size of a rabbit's heart.
Lung
Chronic obstructive pulmonary disease (COPD) is one of the most widespread health threats today. It affects 329 million people worldwide, which makes up nearly 5% of the global population. Having killed over 3 million people in 2012, COPD was the third greatest cause of death. Worse still, due to increasing smoking rates and the aging populations in many countries, the number of deaths as a result of COPD and other chronic lung diseases is predicted to continue increasing. Therefore, developments in the lung's capacity for regeneration is in high demand.
It has been shown that bone marrow-derived cells could be the source of progenitor cells of multiple cell lineages, and a 2004 study suggested that one of these cell types was involved in lung regeneration. Therefore, a potential source of cells for lung regeneration has been found; however, due to advances in inducing stem cells and directing their differentiation, major progress in lung regeneration has consistently featured the use of patient-derived iPSCs and bioscaffolds.
The extracellular matrix is the key to generating entire organs in vitro. It was found that by carefully removing the cells of an entire lung, a "footprint" is left behind that can guide cellular adhesion and differentiation if a population of lung epithelial cells and chondrocytes are added. This has serious applications in regenerative medicine, particularly as a 2012 study successfully purified a population of lung progenitor cells that were derived from embryonic stem cells. These can then be used to re-cellularise a three-dimensional lung tissue scaffold.
A 2010 investigation used the ECM scaffold to produce entire lungs in vitro to be transplanted into living rats. These successfully enabled gas exchange but for short time intervals only. Nevertheless, this was a huge leap towards whole lung regeneration and transplants for humans, which has already taken another step forward with the lung regeneration of a non-human primate.
Cystic fibrosis is another disease of the lungs, which is highly fatal and genetically linked to a mutation in the CFTR gene. Through growing patient-specific lung epithelium in vitro, lung tissue expressing the cystic fibrosis phenotype has been achieved. This is so that modelling and drug testing of the disease pathology can be carried out with the hope of regenerative medical applications.
Penis
Penises have been successfully regenerated in the lab. Penises are harder to regenerate than the skin, bladder and vagina due to their structural complexity.
Spinal nerves
A goal of spinal cord injury research is to promote neuroregeneration, reconnection of damaged neural circuits. The nerves in the spine are a tissue that requires a stem cell population to regenerate. In 2012, a Polish fireman Darek Fidyka, with paraplegia of the spinal cord, underwent a procedure, which involved extracting olfactory ensheathing cells (OECs) from Fidyka's olfactory bulbs, and injecting these stem cells, in vivo, into the site of the previous injury. Fidyka eventually gained feeling, movement and sensation in his limbs, especially on the side where the stem cells were injected; he also reported gaining sexual function. Fidyka can now drive and can now walk some distance aided by a frame. He is believed to be the first person in the world to recover sensory function from a complete severing of the spinal nerves.
Thymus
The thymus gland is one of the first organs to degenerate in normal healthy individuals. Researchers from the University of Edinburgh have succeeded in regenerating a living organ that closely resembles a juvenile thymus in terms of structure and gene expression profile.
Vagina
Between the years 2005 and 2008, four women with vaginal hypoplasia due to Müllerian agenesis were given regenerated vaginas. Up to eight years after the transplants, all organs have normal function and structure.
See also
Cloning
Decellularization
Induced pluripotent stem cell
Life extension
Rejuvenation (aging)
Stem cell treatments
Tissue engineering
References
Further reading
External links
UCI Limb Regeneration Lab
Vertebrate developmental biology
Human biology
Senescence | Regeneration in humans | [
"Chemistry",
"Biology"
] | 5,476 | [
"Senescence",
"Metabolism",
"Human biology",
"Cellular processes"
] |
44,465,987 | https://en.wikipedia.org/wiki/Non-constructive%20algorithm%20existence%20proofs | The vast majority of positive results about computational problems are constructive proofs, i.e., a computational problem is proved to be solvable by showing an algorithm that solves it; a computational problem is shown to be in P by showing an algorithm that solves it in time that is polynomial in the size of the input; etc.
However, there are several non-constructive results, where an algorithm is proved to exist without showing the algorithm itself. Several techniques are used to provide such existence proofs.
Using an unknown finite set
In combinatorial game theory
A simple example of a non-constructive algorithm was published in 1982 by Elwyn R. Berlekamp, John H. Conway, and Richard K. Guy, in their book Winning Ways for Your Mathematical Plays. It concerns the game of Sylver Coinage, in which players take turns specifying a positive integer that cannot be expressed as a sum of previously specified values, with a player losing when they are forced to specify the number 1. There exists an algorithm (given in the book as a flow chart) for determining whether a given first move is winning or losing: if it is a prime number greater than three, or one of a finite set of 3-smooth numbers, then it is a winning first move, and otherwise it is losing. However, the finite set is not known.
In graph theory
Non-constructive algorithm proofs for problems in graph theory were studied beginning in 1988 by Michael Fellows and Michael Langston.
A common question in graph theory is whether a certain input graph has a certain property. For example:
Input: a graph G.
Question: Can G be embedded in a 3-dimensional space, such that no two disjoint cycles of G are topologically linked (as in links of a chain)?
There is a highly exponential algorithm that decides whether two cycles embedded in a 3d-space are linked, and one could test all pairs of cycles in the graph, but it is not obvious how to account for all possible embeddings in a 3d-space. Thus, it is a-priori not clear at all if the linkedness problem is decidable.
However, there is a non-constructive proof that shows that linkedness is decidable in polynomial time. The proof relies on the following facts:
The set of graphs for which the answer is "yes" is closed under taking minors. I. e., if a graph G can be embedded linklessly in 3-d space, then every minor of G can also be embedded linklessly.
For every two graphs G and H, it is possible to find in polynomial time whether H is a minor of G.
By Robertson–Seymour theorem, any set of finite graphs contains only a finite number of minor-minimal elements. In particular, the set of "yes" instances has a finite number of minor-minimal elements.
Given an input graph G, the following "algorithm" solves the above problem:
For every minor-minimal element H:
If H is a minor of G then return "yes".
return "no".
The non-constructive part here is the Robertson–Seymour theorem. Although it guarantees that there is a finite number of minor-minimal elements it does not tell us what these elements are. Therefore, we cannot really execute the "algorithm" mentioned above. But, we do know that an algorithm exists and that its runtime is polynomial.
There are many more similar problems whose decidability can be proved in a similar way. In some cases, the knowledge that a problem can be proved in a polynomial time has led researchers to search and find an actual polynomial-time algorithm that solves the problem in an entirely different way. This shows that non-constructive proofs can have constructive outcomes.
The main idea is that a problem can be solved using an algorithm that uses, as a parameter, an unknown set. Although the set is unknown, we know that it must be finite, and thus a polynomial-time algorithm exists.
There are many other combinatorial problems that can be solved with a similar technique.
Counting the algorithms
Sometimes the number of potential algorithms for a given problem is finite. We can count the number of possible algorithms and prove that only a bounded number of them are "bad", so at least one algorithm must be "good".
As an example, consider the following problem.
I select a vector v composed of n elements which are integers between 0 and a certain constant d.
You have to guess v by asking sum queries, which are queries of the form: "what is the sum of the elements with indices i and j?". A sum query can relate to any number of indices from 1 to n.
How many queries do you need? Obviously, n queries are always sufficient, because you can use n queries asking for the "sum" of a single element. But when d is sufficiently small, it is possible to do better. The general idea is as follows.
Every query can be represented as a 1-by-n vector whose elements are all in the set {0,1}. The response to the query is just the dot product of the query vector by v. Every set of k queries can be represented by a k-by-n matrix over {0,1}; the set of responses is the product of the matrix by v.
A matrix M is "good" if it enables us to uniquely identify v. This means that, for every vector v, the product M v is unique. A matrix M is "bad" if there are two different vectors, v and u, such that M v = M u.
Using some algebra, it is possible to bound the number of "bad" matrices. The bound is a function of d and k. Thus, for a sufficiently small d, there must be a "good" matrix with a small k, which corresponds to an efficient algorithm for solving the identification problem.
This proof is non-constructive in two ways: it is not known how to find a good matrix; and even if a good matrix is supplied, it is not known how to efficiently re-construct the vector from the query replies.
There are many more similar problems which can be proved to be solvable in a similar way.
Additional examples
Some computational problems can be shown to be decidable by using the Law of Excluded Middle. Such proofs are usually not very useful in practice, since the problems involved are quite artificial.
An example from Quantum complexity theory (related to Quantum query complexity) is given in.
References
Credits
The references in this page were collected from the following Stack Exchange threads:
See also
Existence theorem#'Pure' existence results
Constructive proof#Non-constructive proofs
Computational complexity theory
Constructivism (mathematics) | Non-constructive algorithm existence proofs | [
"Mathematics"
] | 1,378 | [
"Mathematical logic",
"Constructivism (mathematics)"
] |
44,466,040 | https://en.wikipedia.org/wiki/Peyronellaea%20curtisii | Peyronellaea curtisii (leaf scorch) is a fungal plant pathogen first described by Miles Joseph Berkeley and received its current name in 2010.
Formerly it was Stagonospora (syn. Stagonosporopsis) curtisii. It is a cause of leaf blotch, and its substrates include Narcissus, Galanthus and Hippeastrum.
Symptoms
Peyronellaea curtisii causes red-brown spots on leaf tips of Narcissus and other members of the family Amaryllidaceae; this gives them a scorched appearance that is easily mistaken for frost damage. A yellowish discolouration then spreads down the leaf; more spots may develop as the leaf withers, turns brown and die away. Minute black fungal fruiting bodies may be visible on the foliage. The flowers and flower stalks may also display brown spots and marks.
On hippeastrum bulbs the fungus causes red spots that may develop into soft, sunken patches. Leaf scorch fungus can also affect other members of the Amaryllidaceae, including Amaryllis, Crinum, Nerine, Sprekelia and Sternbergia.
References
Bibliography
Fungal plant pathogens and diseases
Pleosporales
Fungi described in 2010
Fungus species | Peyronellaea curtisii | [
"Biology"
] | 259 | [
"Fungi",
"Fungus species"
] |
44,466,777 | https://en.wikipedia.org/wiki/Theta%20constant | In mathematics, a theta constant or
Thetanullwert' (German for theta zero value; plural Thetanullwerte) is the restriction θm(τ) = θm(τ,0) of a theta function θm(τ,z) with rational characteristic m to z = 0. The variable τ may be a complex number in the upper half-plane in which case the theta constants are modular forms, or more generally may be an element of a Siegel upper half plane in which case the theta constants are Siegel modular forms. The theta function of a lattice is essentially a special case of a theta constant.
Definition
The theta function θm(τ,z) = θa,b(τ,z)is defined by
where
n is a positive integer, called the genus or rank.
m = (a,b) is called the characteristic
a,b are in Rn
τ is a complex n by n matrix with positive definite imaginary part
z is in Cn
t means the transpose of a row vector.
If a,b are in Qn then θa,b(τ,0) is called a theta constant.
Examples
If n = 1 and a and b are both 0 or 1/2, then the functions θa,b(τ,z) are the four Jacobi theta functions, and the functions θa,b(τ,0) are the classical Jacobi theta constants. The theta constant θ1/2,1/2(τ,0) is identically zero, but the other three can be nonzero.
References
Automorphic forms
Modular forms | Theta constant | [
"Mathematics"
] | 331 | [
"Modular forms",
"Number theory"
] |
44,466,971 | https://en.wikipedia.org/wiki/Biased%20random%20walk%20on%20a%20graph | In network science, a biased random walk on a graph is a time path process in which an evolving variable jumps from its current state to one of various potential new states; unlike in a pure random walk, the probabilities of the potential new states are unequal.
Biased random walks on a graph provide an approach for the structural analysis of undirected graphs in order to extract their symmetries when the network is too complex or when it is not large enough to be analyzed by statistical methods. The concept of biased random walks on a graph has attracted the attention of many researchers and data companies over the past decade especially in the transportation and social networks.
Model
There have been written many different representations of the biased random walks on graphs based on the particular purpose of the analysis. A common representation of the mechanism for undirected graphs is as follows:
On an undirected graph, a walker takes a step from the current node, to node Assuming that each node has an attribute the probability of jumping from node to is given by:
where represents the topological weight of the edge going from to
In fact, the steps of the walker are biased by the factor of which may differ from one node to another.
Depending on the network, the attribute can be interpreted differently. It might be implied as the attraction of a person in a social network, it might be betweenness centrality or even it might be explained as an intrinsic characteristic of a node. In case of a fair random walk on graph is one for all the nodes.
In case of shortest paths random walks is the total number of the shortest paths between all pairs of nodes that pass through the node . In fact the walker prefers the nodes with higher betweenness centrality which is defined as below:
Based on the above equation, the recurrence time to a node in the biased walk is given by:
Applications
There are a variety of applications using biased random walks on graphs. Such applications include control of diffusion, advertisement of products on social networks, explaining dispersal and population redistribution of animals and micro-organisms, community detections, wireless networks, and search engines.
See also
Betweenness centrality
Community structure
Kullback–Leibler divergence
Markov chain
Maximal entropy random walk
Random walk closeness centrality
Social network analysis
Travelling salesman problem
References
External links
Gábor Simonyi, "Graph Entropy: A Survey". In Combinatorial Optimization (ed. W. Cook, L. Lovász, and P. Seymour). Providence, RI: Amer. Math. Soc., pp. 399–441, 1995.
Anne-Marie Kermarrec, Erwan Le Merrer, Bruno Sericola, Gilles Trédan, "Evaluating the Quality of a Network Topology through Random Walks" in Gadi Taubenfeld (ed.) Distributed Computing
Network theory
Social networks
Social systems
Social information processing | Biased random walk on a graph | [
"Mathematics"
] | 576 | [
"Network theory",
"Mathematical relations",
"Graph theory"
] |
44,467,899 | https://en.wikipedia.org/wiki/IMPLY%20gate | The IMPLY gate is an informal digital logic gate that implements a logical conditional.
Symbols
IMPLY can be denoted in algebraic expressions with the logic symbol right-facing arrow (→). Logically, it is equivalent to material implication, and the logical expression ¬A v B.
There are two symbols for IMPLY gates: the traditional symbol and the IEEE symbol. For more information see Logic gate symbols.
Functional completeness
While the Implication gate isn't functionally complete by itself, it is in conjunction with the constant 0 source. This can be shown via the following:
Thus as the implication gate with the addition of the constant 0 source can create both the NOT gate and the OR gate, it can create the NOR gate, which is a universal gate.
See also
NIMPLY gate
AND gate
NOT gate
NAND gate
NOR gate
XOR gate
XNOR gate
Boolean algebra (logic)
Logic gates
Logic gates | IMPLY gate | [
"Technology"
] | 182 | [
"Computing stubs"
] |
44,468,915 | https://en.wikipedia.org/wiki/Polyandry%20in%20animals | In behavioral ecology, polyandry is a class of mating system where one female mates with several males in a breeding season. Polyandry is often compared to the polygyny system based on the cost and benefits incurred by members of each sex. Polygyny is where one male mates with several females in a breeding season (e.g., lions, deer, some primates, and many systems where there is an alpha male).
A common example of polyandrous mating can be found in the field cricket (Gryllus bimaculatus) of the invertebrate order Orthoptera (containing crickets, grasshoppers, and groundhoppers). Polyandrous behavior is also prominent in many other insect species, including the red flour beetle, the adzuki bean weevil, and the species of spider Stegodyphus lineatus. Polyandry also occurs in some primates such as marmosets, mammal groups, the marsupial genus' Antechinus and bandicoots, around 1% of all bird species, such as jacanas and dunnocks, insects such as honeybees, and fish such as pipefish.
Predictors of polyandry
It is theorized that polyandry is more prevalent in organisms where incompatibility is more costly, and where this incompatibility is more likely. The former is especially true in viviparous organisms. Where the cost of having a low-quality father is significant, however, an organism is less likely to be polyandrous.
Benefits and costs of mating for females
The adaptive significance of polyandry in animals is controversial. Polyandry has direct benefits for females allowing fertilization assurance, provision of resources, and parental care for their offspring. House mice (Mus musculus musculus) have shown indirect, genetic benefits, where females have increased offspring survival through multiple mating, showing that practicing polyandry mating results in an increase in offspring viability. In a meta analysis, including 10 different orders of insects, polyandry increased the production of eggs by females specifically in Lepidopterans and Orthopterans. Indirect benefits of mating for females can be gained through sperm competition to attain "good genes", cryptic female choice, increased genetic quality, and genetic diversity. Females spiders (Pisaura mirabilis) store more sperm from gift-giving males suggesting that sperm storage is under female control through cryptic sperm choice. The increase in sperm storage from the gift giving males might allow females to produce "sexy sons" that also give gifts and increase the fitness of offspring. Sperm storage and fertilization success increased with copulation duration, suggesting an advantage in sperm competition.
Many reptile species also demonstrate polyandry, especially among members of the tortoise family (Testudinidae). Through polyandry and long-term sperm storage, recent studies have found evidence for the ability of female tortoises to produce clutches of eggs that demonstrate multiple paternity. Predictably, these hatchlings showed an increase in genetic variability compared to those sired by a single male. Potential for multiple paternity within a clutch is primarily a result of sperm storage across reproductive cycles, since studies have confirmed the presence of multiple males' sperm in the female tortoise reproductive tract simultaneously. As a result of clutches with greater variation in paternal genes and increased sperm competition, females can maximize both the genetic quality and number of offspring. Multiple paternities within a single clutch is therefore considered an effective strategy to increase the reproductive success and fitness of female tortoises.
Acorn woodpeckers provide substantial information on breeding systems because they practice monogamy, polyandry, and polygyny. In polyandry the presence of more male breeders in acorn woodpeckers has shown that females reproduce the optimal clutch size and that with paternity sharing between males it is behaviorally more stable increasing male and female fitness. As opposed to polygyny, where it has been observed that polygynous females that lay a large number of eggs exceeding the optimal clutch size reduces the fitness of the group. Polygynous trios compared to polyandrous trios showed that having more eggs lowered the group fitness. Chao (1997) studies using acorn woodpeckers suggest that other mating systems are practiced at a lower rate when compared to polyandry because it is polyandry that can maximize the fitness of males and females when obtaining optimal clutch size. In polyandrous mating, optimal clutch size is obtained because there is only one female and it becomes more stable when all members remain together.
Multiple mating is also seen in wattled jacanas where females have a group of males close by for mating. Copulations are easily seen in jacanas, facilitating the observation of females copulating continuously with various males. The continuous copulations and the close proximity to mates have allowed the females to fly in within minutes leading to the expected sperm mixing and allowing the most viable sperm to fertilize most of the clutch or to increase genetic diversity for benefits in disease resistance. Snow and Andrade (2005) concluded that the redback spider (Latrodectus hasselti) increases their ability to manipulate the paternity of their offspring by using the spermathecae to store multiple sperms. Additionally, a study on leaf-cutting ants (Acromyrmex echinatior) supported the hypothesis that sperm mixing indeed occurs in polyandrous social insects. It was further found that the eggs in the queen ants showed to be completely mixed and used randomly during egg laying.
According to Gordon G. Gallup, as a form of adapting to multiple mating in females, human penile shape is indicative of an evolutionary history of polyandry. Male humans evolved to have a wedge- or spoon-shaped glans and to perform repeated thrusting motions during copulation in order to draw foreign semen back away from the cervix and thus to compete with sperm of other males.
Polyandry may also impose costs on females, exposing them to diseases, increased predation risk, time and energy costs, and even physical harm due to sexual harassment. Polyandrous females encounter sexual harassment when courted by males resulting to be costly to females. In order to reduce the costs to the females, females will take part in polyandry. For example, in the bee species Anthidium maculosum, like in many other species, the high cost of resisting mating may exceed the cost of accepting numerous males in a breeding if copulating takes a short time, and therefore females in some species are inclined to being polyandrous. In the polyandrous system, sexual coercion has been observed to be one of the major reasons for why females begin to mate with multiple males to outweigh the cost under different circumstances. The sexual conflict hypothesis suggest that polyandry can occur due to sexual coercion preventing females from obtaining any benefits. Sexual coercion has been seen in three different forms: forced copulation, sexual harassment, and intimidation. Forced copulation is seen in those males that cannot gain access to females for mating. As a result of the lack of access to mates, males are more likely to engage in sexually aggressive behaviors that could result in physical harm and death for females, as has been observed in elephant seals and ducks. Intimidation was seen in social primates, who coerce females into mating, therefore, pushing them to mate with their own aggressor. Males use intimidation as a method of punishment in females that do not mate with them.
Sexual coercion has many benefits to males allowing them to mate, but their strategies pose high cost for females. This has been observed in vertebrates like green turtles. The green turtles is an example of a species that does not receive any possible benefit from polyandry and only uses it to reduce the cost of mating. As for house mice, multiple male mating was observed even when females had the opportunity to select their mate without sexual coercion, showing that it was due to female choice. In the fly Dryomyza anilis, females favor matings with quick oviposition. D. anilis females can store sperm for at least two egg batches without their fertilization rate decreasing. Therefore, mating before each oviposition is not necessary. There is no significant overall benefit for females in multiple matings; large females are at an advantage due to their ability to resist unnecessary matings.
As a result of multiple male mating, multiple paternities were observed in species as a result of convenience polyandry. Convenience Polyandry Hypothesis is the assumption that there is a greater cost for females when, refusing male mating attempts than in choice mating. It is the situation in which females adjust their mating rate to balance the costs of male harassment. It has been suggested that convenience polyandry would increase when females are weaker than males, decreasing the costs of sexual aggression. Convenience polyandry is seen in several arthropod species, like water striders (Gerris buenoi).
Paternity sharing
Males that compete for more mating opportunities are the ones that have shown less cooperation in breeding. However, there are other males that in order to gain access to females and mating opportunities practice parental care. Such parental care is mostly seen in polyandrous mating systems; but they must go through the cost of sharing paternity and parental care. This has been observed in avians like acorn woodpeckers (Melanerpes formicivorus), and fishes as the cichlid fish (Julidochromis transcriptus). Observations that show male relatedness suggest the importance for male social relationships in taking care of offspring. These social relationships in males are seen in primates, Geoffroy's tamarins, Saguinus geoffroyi. High proportions of related males at the half sibling or higher were found.
As for frog species, rhacaphorid frog (Kurixalus eiffingeri), is one of the few that is polyandrous and exhibits parental care of eggs. The male frogs sit on the egg clutches, maintaining contact with the eggs. Parental care and males genetic contribution were found significantly correlated meaning that male frogs with a higher paternity attended their eggs far more significantly than those of partial paternity for the clutch. Females that mate with more than one male obtain the aid of both and as a result of all three parents providing food and care to the offspring there is an increase in the survival of their young. The amount of help is determined based on mating share and paternity share. (Mating Systems, p 275)
In polyandrous mating it has been suggested that male cooperation may outweigh the costs of sharing paternity in situations of scarcity, of foods and of high competition levels for land or females. Female size and a large breeding territory defended by more males may force male cooperation. For males, such factors can promote an increase in reproductive success, leaving behind the cost of paternity share (Mating Systems, p277). Comb-crested jacana's (Irediparra gallinacea) has shown genetic evidence for paternity assurance. The comb-crested jacana females had one to three more mates available for copulation. In order to guarantee paternity to their male mates, the females would spend time in the territory of the male, laying her eggs.
Some taxa with high social organization are eusocial, meaning that a single female (e.g., the queen bee) or caste produces offspring while the other organisms (e.g., non-reproductive female worker bees) cooperate in caring for the young. Examples of mammalian eusociality include Damaraland mole-rats and naked mole-rats, among whom polyandry is the norm and polygyny has never been observed.
Polyandry and infanticide avoidance
Infanticide avoidance is one of the major reasons animals, like mammals, are inclined to choose polyandry. Infanticide is observed to be the major cause of mortality in various mammals. Polyandry is thought to evolve from their offspring's vulnerability to infanticide. There is evidence that polyandry is an effective strategy that is adapted by many to increase their offspring survival through the avoidance of male infanticide. Bank voles (Myodes glareolus) has supported the infanticide avoidance hypothesis where polyandrous females' offspring have a higher survival than monandrous females' offspring.
Polyandry benefit exception: green turtles
High levels of multiple paternity have widely been seen and reported in snakes, marine turtles, and lizards. However, Lee and Hayes (2004) have evidence that suggests that there is no set data in green turtles that significantly shows that there are potential fitness gains through polyandry. Instead, it is suggested that the multiple mating is a result of male aggression. Both Wright and Lee and Hayes studies exhibit similar results that show a lack of support of the indirect benefits of polyandry. In addition, they pose that there is no relationship between multiple paternity and reproductive success. Multiple male paternity is present in green turtles, but no significant fitness benefits have been found. Observations done on clutches showed that there was no correlation of reproductive success when mating with multiple males.
Callitrichidae
Current research suggests that polyandry is the dominant social structure in the New World monkey family Callitrichidae. The Callitrichidae includes marmosets and tamarins, two groups of small New World monkeys found in South America. Wild groups usually consist of three to ten individuals, with one reproductively active female, one or more reproductive males, and several nonreproductive helpers that can be either male or female. Cooperative polyandry is not the only mating system found in these primates. Polyandrous, monogamous, and polygynous groups can be found within the same population, and a group can even change mating systems, making it the most flexible mating system of any non-human primate. Unlike most primates who typically give birth to single young, twins are the average litter size for tamarins and marmosets. The entire group participates in raising the offspring, sharing the responsibilities of infant carrying, feeding, and grooming. The presence of nonreproductive helpers appears to be the most important factor in determining which mating system is used, as ecological and environmental variability have not been found to have a significant impact. Goldizen (1987) proposed the hypothesis that monogamy in Callitrichidae should develop only in groups with nonreproductive helpers to help raise the young, and in the absence of these helpers, both polyandrous males and females would have higher reproductive success than those in lone monogamous pairs. Indeed, in studies of Saguinus fuscicollis, common name saddle-back tamarin, no monogamous lone pairs have ever been seen to attempt a breeding cycle.
See also
Green-veined white
Polyandry in fish
Superfecundation
Bibron's toadlet
References
Animal sexuality
Ethology
Reproduction in animals
Mating systems
Polyandry | Polyandry in animals | [
"Biology"
] | 3,106 | [
"Reproduction in animals",
"Behavior",
"Animals",
"Reproduction",
"Behavioural sciences",
"Animal sexuality",
"Ethology",
"Mating systems",
"Sexuality",
"Mating"
] |
44,470,019 | https://en.wikipedia.org/wiki/Nidula%20shingbaensis | Nidula shingbaensis is a rare species of bird's nest fungus in the family Agaricaceae. Found in the north district of Sikkim (India), where it grows on small fallen twigs of Bhutan fir (Abies densa), it was described as new to science in 2013. It has a peridium measuring 6–9 mm tall with a mouth diameter of 5–7 mm. The peridium contains up to 40 small "eggs" (peridioles) measuring 0.9–1.3 mm in diameter. The peridioles are filled with broadly ellipsoid to elongated spores that are 6.9–8.3–9.8 by 4.9–5.4–6.1 μm. Measuring 650–720 μm thick, the peridium comprises six distinct tissue layers—a feature that is unique in the genus Nidula.
References
External links
Agaricaceae
Fungi described in 2013
Fungi of India
Fungus species | Nidula shingbaensis | [
"Biology"
] | 204 | [
"Fungi",
"Fungus species"
] |
44,470,364 | https://en.wikipedia.org/wiki/Tufts%20Center%20for%20the%20Study%20of%20Drug%20Development | The Tufts Center for the Study of Drug Development is an independent, academic, non-profit research center at Tufts University in Boston, dedicated to researching drug development. It was established in 1976 by American physician Louis Lasagna. The Center develops and publishes information to help researchers, regulators, and policy makers in areas related to the pharmaceutical and biotechnology industries. In any given year, approximately 55% of Tufts CSDD's operating expenses are supported by grants from the private sector and 45% from the public sector.
Research
The Center studies trends in the pharmaceutical industry, maintaining databases pertaining to investigational new drugs, approved drugs, biopharmaceuticals, fast-tracked drugs, and orphan drugs. The Center provides this information with the aim to improve the efficiency of drug development, foster innovation, and increase patient access to medicines.
Drug development costs
The center has published numerous studies estimating the cost of developing new pharmaceutical drugs. In 2001, researchers from the Center estimated that the cost of doing so was $802 million, and in 2014, they released a study estimating that this amount had risen to nearly $2.6 billion. The 2014 study was criticized by Medecins Sans Frontieres, which said it was unreliable because the industry's research and development spending is not made public. Aaron Carroll of the New York Times also criticized the study, saying it "contains a lot of assumptions that tend to favor the pharmaceutical industry." The center's 2016 estimate, published in the Journal of Health Economics, found the cost to have averaged $2.87 billion (in 2013 dollars).
References
Tufts University
1976 establishments in Massachusetts
Non-profit organizations based in Boston
Organizations established in 1976
Drug discovery | Tufts Center for the Study of Drug Development | [
"Chemistry",
"Biology"
] | 343 | [
"Drug discovery",
"Life sciences industry",
"Medicinal chemistry"
] |
44,470,705 | https://en.wikipedia.org/wiki/Ziegler%20process | In organic chemistry, the Ziegler process (also called the Ziegler-Alfol synthesis) is a method for producing fatty alcohols from ethylene using an organoaluminium compound. The reaction produces linear primary alcohols with an even numbered carbon chain. The process uses an aluminum compound to oligomerize ethylene and allow the resulting alkyl group to be oxygenated. The usually targeted products are fatty alcohols, which are otherwise derived from natural fats and oils. Fatty alcohols are used in food and chemical processing. They are useful due to their amphipathic nature. The synthesis route is named after Karl Ziegler, who described the process in 1955.
Process details
The Ziegler alcohol synthesis involves oligomerization of ethylene using triethylaluminium followed by oxidation. The triethylaluminium is produced by action of aluminium, ethylene, and hydrogen gas. In the production process, two-thirds of the triethylaluminium produced is recycled back into the reactor, and only one-third is used to produce the fatty alcohols. The recycling step is used to produce triethylaluminium at a higher yield and with less time. Triethylaluminium reacts with ethylene to form higher molecular weight trialkylaluminium. The number of equivalents of ethylene n equals the total number of monomer units being grown on the initial ethylene chains, where (n = x + y + z), and x, y, and z are the number of ethylene units per chain. Trialkylaluminium is oxidized with air to form aluminum alkoxides, and finally hydrolyzed to aluminum hydroxide and the desired alcohols.
Al+3ethylene+1.5H2 → Al(C2H5)3
Al(C2H5)3 n-ethylene → Al((CH2CH2)nCH2CH3)3
Al((CH2CH2)nCH2CH3)3+ O2 → Al(O(CH2CH2)nCH2CH3)3
Al(O(CH2CH2)nCH2CH3)3+3H2O → Al(OH)3 + CH3CH2(CH2CH2)nOH
The temperature of the reaction influences the molecular weight of alcohol growth. Temperatures in the range of 60-120°C form higher molecular weight trialkylaluminium while higher temperatures (e.g., 120-150 °C) cause thermal displacement reactions that afford α-olefin chains. Above 150 °C, dimerization of the α-olefins occurs.
Applications
Aluminum hydroxide, the byproduct of the synthesis, can be dehydrated to give aluminium oxide, which, at high purities, has a high commercial value. One modification of the Ziegler process is called the EPAL process. In this process, chain growth is optimized to produce alcohols with narrow molecular weight distribution. Synthesis of other alcohols use Ziegler and the updated EPAL process, such as the transalkylation of styrene to form 2-phenylethanol. Diethylaluminum hydride can be employed in place of triethylaluminium.
See also
Guerbet reaction, a route for the production of branched fatty alcohols
References
Fatty alcohols
Chemical processes | Ziegler process | [
"Chemistry"
] | 712 | [
"Chemical process engineering",
"Chemical processes",
"nan"
] |
44,472,220 | https://en.wikipedia.org/wiki/Food%20choice%20of%20older%20adults | Research into food preferences in older adults and seniors considers how people's dietary experiences change with ageing, and helps people understand how taste, nutrition, and food choices can change throughout one's lifetime, particularly when people approach the age of 70 or beyond. Influencing variables can include: social and cultural environment, gender and/or personal habits, and also physical and mental health. Scientific studies have been performed to explain why people like or dislike certain foods and what factors may affect these preferences.
The science of food preferences
Research in this area is usually done in order to examine the variables that cause the elderly to change their food preferences; an example is the Elderly Nutrition Program (ENP). The ENP was implemented in 1972 to explore how food preferences varied depending on biological sex and ethnic groups, the goal being to improve the quality of meal programs.
Meals and preferences for 13 food groups, including fresh fruit, chicken, soup, salad, vegetables, potatoes, meat, sandwiches, pasta, canned fruit, legumes, deli meats, and ethnic foods, were assessed in order to gain a general impression of people's dietary habits and food preferences. After adjusting for variables, older male subjects were found to be significantly more likely to prefer deli meats, meat, legumes, canned fruit, and ethnic foods compared to females. In addition, compared with African Americans, the study found that "... Caucasians demonstrated higher percentages of preference for 9 of 13 food groups including pasta, meat, and fresh fruit", and recommended that "... To improve the quality of the ENP, and to increase dietary compliance of the older adults to the programs, the nutritional services require a strategic meal plan that solicits and incorporates older adults' food preferences".
Influences on food preference
There are multiple factors in an elderly person's life that can affect food preferences. Aspects like their environment, mental and physical health, and lifestyle choices can all contribute to the individual taste and/or habits of elderly people.
An article about Influences on Cognitive Function in Older Adults (Neuropsychology, November 2014) states that "the nutritional status of older adults relates to their quality of life, ability to live independently, and their risk for developing costly chronic illnesses. An aging adult’s nutritional well-being can be affected by multiple socio-environmental factors, including access to healthy and affordable foods, congregate meal sites, and nutritious selections at restaurants. The Academy of Nutrition and Dietetics, American Society for Nutrition, and the Society for Nutrition Education have identified an older adult's access to a balanced diet to be critical for the prevention of disease and promotion of nutritional wellness so that quality of life and independence can be maintained throughout the aging process and excessive health care costs can be reduced".
Younger vs. older adults
A person's taste buds, needs for certain vitamins and other nutrients, and their desire for different types of food can change throughout that person's life. 50 young adults and 48 elderly adults participated in a study by the Monell Chemical Senses Center. "Young" subjects ranged from 18 to 35 years of age, and "elderly" subjects were defined as 65 years of age or older. There were more females than males in the study, but there were approximately equal proportions of males and females in the two age groups.
The study observed that younger females had stronger cravings for sweets than elderly females. Possible causes considered for this difference were the younger female test subjects' menstrual cycles and the fact that elderly women may have gone through menopause. The study also postulated that "... Ninety-one percent (91%) of the cycle-associated cravings were said to occur in the second half of the cycle (between ovulation and the start of menstruation)".
These physical changes can be considered when assessing why an older person might not be getting the nutrition they need. As taste buds change with age, certain foods might not be seen as appetizing. For example, a study done by Dr. Phyllis B. Grzegorczyk concluded that as people age, their sense for tasting salty foods slowly goes away.
Male vs. female
There are differences in food preferences between the sexes. In a study conducted by the ENP, preferences of male and female subjects were identified in the following 13 individual food groups: fresh fruit, chicken, soup, salad, vegetables, potatoes, meat, sandwiches, pasta, canned fruit, legumes, deli meats, and ethnic groups.
Through this study, it was apparent that older males were "significantly more likely to prefer deli meats, meat, legumes, canned fruit, and ethnic foods compared to females".
Another study by the Monell Chemical Senses Center concluded that females had significantly more cravings for sweets and for chocolate than males; and the study results suggested that males had more cravings or preferences for entrées than sweets.
Personal health
Physical health
Some older people avoid certain foods or are unwilling to modify their diets due to oral health problems. These issues, such as ill-fitting dentures (false teeth) or gum disease, are correlated with significant differences in dietary quality, which is a measure of the quality of the diet using a total of eight recommendations regarding the consumption of foods and nutrients from the National Academy of Sciences (NAS). Approaches to minimize food avoidance and promote changes to the diets of people with eating difficulties due to oral health conditions are needed desperately, because without being able to chew or take in food properly, their health is affected dramatically, and their food preferences are limited greatly (too soft or liquids only).
Due to varying factors in older adults' physical and mental well-being, eating choices can become more restricted. Many elderly people are forced into eating softer foods, foods that incorporate fiber and protein, drinking calcium-packed liquids, and so on. Six of the leading causes of death for older adults, including cardiovascular disease, cancer, chronic lower respiratory disease, stroke, Alzheimer's disease, and diabetes mellitus, have nutrition-related causes and/or respond favorably to nutrition interventions. These six illnesses can implement certain restrictions and heavily influence the diet of elderly persons.
Declines in physical health, such as conditions like arthritis, can also cause deterioration in diet due to difficulties in preparing and eating food.
At the 2010 "Providing Healthy and Safe Foods As We Age" conference sponsored by the Institute of Medicine, Dr. Katherine Tucker noted that the elderly are less active and have lower metabolic rates, with a consequent reduced need to eat. In addition, they tend to have existing diseases and/or take medications that interfere with nutrient absorption. Based on their research dietary requirements, one study developed a modified food pyramid for adults over 70.
There is not enough evidence to confidently recommend the use of any form of carbohydrate in preventing or reducing cognitive decline in older adults with normal cognition or mild cognitive impairment. More evidence is needed to evaluate memory improvement and find nutritional issues due to carbohydrates.
Mental health
The impact of certain diseases can also impact the quality of the food in the elderly population, especially those that are in care facilities. Certain risk factors include conditions that impair cognitive function, such as dementia. When a person falls victim to a condition that limits mental capacity, mortality risk can rise if due care is not implemented.
As a result of certain mental health conditions and/or diseases—like Alzheimer's disease—a person's food preferences might become affected. With certain diseases, individuals can develop specific preferences or distaste for various types of food that were not present before onset. For example, people with Alzheimer's disease may experience many big and small changes as a result of their symptoms. One change identified by Suszynski in "How Dementia Tampers with Taste Buds" is within the taste buds of a patient with dementia, which contain the receptors for taste. Since the experience of flavor is significantly altered, people with dementia can often change their eating habits and take on entirely new food preferences. In this study, the researchers found that these dementia patients had trouble identifying flavors and appeared to have lost the ability to remember tastes, therefore leading to a theory that dementia caused the patients to lose their knowledge of flavors.
Psychological conditions can also affect elderly eating habits. For instance, the length of widowhood may affect nutrition. Depression in elderly people is also associated with a risk of malnutrition.
Lifestyle choices
Elderly people, like all people, have different lifestyle choices involved in their eating habits. Dietary choices are often a result of personal beliefs and preferences.
A survey based on self-reporting found that many rural elderly Iowans adopted eating habits that provided inadequate levels of some key nutrients, and most did not take supplements to correct the deficiencies. In contrast, a restaurant study found that the impact of a lifestyle of health and sustainability on healthy food choices is much stronger for senior diners than for non-senior diners.
Other research has found that adults, regardless of age, will tend to increase fruit and vegetable consumption following a diagnosis of breast, prostate, or colorectal cancer.
Social environment and conditioning
The environment can greatly impact the food preferences of older adults. Those around 75 years old and older are more likely to suffer from limited mobility due to health conditions, and often rely on others for food shopping and preparation.
In some areas, homebound seniors receive one meal per day (several fresh and frozen meals may be included in a single delivery) from communities that offer congregate meals, or meals served in community settings such as senior centers, churches, or senior housing communities. These congregate meal programs are encouraged to offer these elderly people a meal at least five times per week.
Impeded access to transportation may also be an issue for elderly persons, especially in rural areas where there is less public transportation. This can vary greatly with geographic location; for instance, an Iowa-based study failed to find problems in purchasing food among the elderly in rural open country and towns, as those without their own transportation relied on family, friends, and senior services. A separate study found a slight difference in urban areas with elderly who did not own a car. Aside from transportation, the kind and quality of available food can also shape food choices if a person lives in a so-called "food desert".
Social network type can also affect individuals' food choices in our elderly population. For example, one study showed that someone with a larger social network and lower economic status is more likely to have proper nutrition than someone who has a smaller social network and higher economic status. Health and social aid can be instrumental in introducing positive change for those at risk.
See also
Assisted living
Centenarian
Elderly care
Food choice
Food studies
Illnesses related to poor nutrition
List of nutrition guides
Meals on Wheels
Nutrition
Portion size
Research into centenarians
Tea and toast syndrome
References
Old age
Geriatrics
Eating behaviors of humans | Food choice of older adults | [
"Biology"
] | 2,223 | [
"Eating behaviors",
"Behavior",
"Eating behaviors of humans",
"Human behavior"
] |
44,472,759 | https://en.wikipedia.org/wiki/Hydnellum%20auratile | Hydnellum auratile is a tooth fungus in the family Bankeraceae. Fruit bodies of the fungus consist of closely grouped, funnel-shaped caps up to in diameter. The caps are initially bright orange with a white rim, and have a felt-like surface. On the cap underside, the hymenium has hanging orange spines with whitish tips. These spines extend a ways down the length of the short stipe. The flesh is orange in both the cap and stipe. In mass, the spores are brown. Microscopically, they measure 4–5 by 3.5–4.5 μm and have short, rounded tubercles on the surface. The widespread Hydnellum aurantiacum is a close lookalike, but can be distinguished by having a white to buff cap, dull orange to brown flesh, and white spines.
Hydnellum auratile was first described as a species of Hydnum by German mycologist Max Britzelmayr in 1891. Rudolph Arnold Maas Geesteranus transferred it to Hydnellum in 1959. The fungus is widely spread in Europe, and has also been reported from the Pacific Northwest region of North America. It is considered endangered in Switzerland.
References
External links
Fungi described in 1891
Fungi of Europe
Fungi of North America
Inedible fungi
auratile
Taxa named by Max Britzelmayr
Fungus species | Hydnellum auratile | [
"Biology"
] | 281 | [
"Fungi",
"Fungus species"
] |
44,472,774 | https://en.wikipedia.org/wiki/Women%20Who%20Code | Women Who Code (WWCode) was an international non-profit organization that provides services for women pursuing technology careers and a job board for companies seeking coding professionals. The company aims to provide an avenue into the technology world by evaluating and assisting women in developing technical skills.
In addition to training, professional evaluations, meetings, and scholarships, Women Who Code offers networking and mentorship. As of 2023, the organization has held more than 16,000 free events around the world and built a membership of over 343,000 people representing over 147 countries. The current chief executive officer of Women Who Code is Julie Elberfeld.
History
Women Who Code was created in 2011. It was founded as a 501(c)(3) not-for-profit and approved by the IRS in November 2013 and is best known for its weekly publication the CODE Review, free technical study groups, hack nights, career development and leadership development, and speaking events featuring influential technology industry experts and investors. Since inception, WWCode has produced thousands of events worldwide and garnered sponsorship from organizations like Google, Zendesk, VMware, KPCB, Capital One, Nike, Yelp, and many others. In the summer of 2016, Women Who Code went through Y Combinator.
On April 18, 2024, the organization announced it would be shutting down due to lack of funding.
Key initiatives
Women Who Code's initiatives include:
Providing free technical study groups (Ruby, Javascript, iOS, Android, Python, Algorithms)
Connecting members with influential tech experts and investors
Offering career and leadership development
Increasing women speakers and judges at conferences and hackathons
Increasing diverse participation in the tech community
See also
Ladies of Code
References
External links
Forbes: "Women Who Code Present 9 Tech Talks in San Francisco"
Wall Street Journal: "Alaina Percival: 10 Reasons Why More Women Should Work in Software Engineering"
CSM: "Silicon Valley's workforce could see demographic shift"
Venture Beat: "Let's talk about ‘women in tech': Silicon Valley still has a gender problem"
SFBT: "Twitter hosts female-driven hackathon"
computerweekly.com: "Women Who Code launches London meet ups"
Organizations for women in science and technology
Women in science and technology
Y Combinator companies
Non-profit organizations based in the United States
501(c)(3) organizations | Women Who Code | [
"Technology"
] | 479 | [
"Organizations for women in science and technology",
"Women in science and technology"
] |
44,472,954 | https://en.wikipedia.org/wiki/Hydnellum%20compactum | Hydnellum compactum is a rare tooth fungus in the family Bankeraceae. It is characterised by its astringent taste, yellowish flesh. It is found in Europe, where it grows in deciduous forest, typically under beech. Fruit bodies of the fungus grow singly or in groups.
They are top-shaped, with convex or flattened upper surfaces up to in diameter. The surface texture is initially felt-like before becoming pitted and rough in age. The stipe, roughly the same color as the cap, is solid and measures long by thick. On the fertile cap underside (the hymenium), there are white to purple-brown, curved spines up to 5 mm long. The color is whitish at first but gradually turns dark brown to blackish. The spores measure 5.5–6 by 3.5–4.5 μm, and feature tubercles that sometimes have a sunken tip.
Hydnellum compactum is ectomycorrhizal with Sessile Oak (Quercus petraea), Common Oak (Q. robur) and Beech (Fagus sylvatica) as well as Sweet Chestnut (Castanea sativa) occasionally. It prefers in nutrient poor, dry to moist, loamy and sandy soils, and sunny, mosaic, old-growth forests.
It is considered endangered is Switzerland, and listed as vulnerable on the IUCN red list. It is estimated there are less than 4000 mature individuals of this species left in Europe. Its presence has particularly decreased in the Netherlands. Its main threats are logging, as old-growth forests are decreasing across northern and central Europe. In western Europe, this fungus is mainly threatened by air pollution, such as acidificiation and nitrogen deposition.
See also
List of fungi by conservation status
References
Fungi described in 1800
Fungi of Europe
Inedible fungi
compactum
Taxa named by Christiaan Hendrik Persoon
Fungus species | Hydnellum compactum | [
"Biology"
] | 389 | [
"Fungi",
"Fungus species"
] |
44,473,090 | https://en.wikipedia.org/wiki/Hydnellum%20mirabile | Hydnellum mirabile is an inedible species of tooth fungus in the family Bankeraceae. It is found in Europe and North America, where it grows in old-growth, coniferous forests on base-rich or chalky soils. It forms mycorrhiza with Norway Spruce and occasionally Scots Pine.
Caps are brownish to dark brown with yellow edges, and have a hairy surface. They are funnel-shaped.The stipe measures 10-50 x 10-25mm and is dark brown and hairy at the base. On the cap underside (the hymenium) hang brownish spines with paler tips. The spores are roughly spherical with tubercles on the surface, and measure 5–7 by 4.5–6 μm. It has a weakly astringent taste. The spore print in buff brown.
It is estimated that there are less than 5000 mature individuals of this species in Europe, due to the impacts of forestry on old-growth forests. Particularly in its central European localities, Hydnellum mirabile is threatened by air pollution, particularly nitrogen deposition. Finland and Norway consider Hydnellum mirabile as vulnerable, France and Sweden consider it endangered, and the Czech Republic consider it as regionally extinct.
See also
List of fungi by conservation status
References
Fungi described in 1863
Fungi of Europe
Fungi of North America
Inedible fungi
Taxa named by Elias Magnus Fries
Fungus species | Hydnellum mirabile | [
"Biology"
] | 290 | [
"Fungi",
"Fungus species"
] |
44,476,255 | https://en.wikipedia.org/wiki/Finite%20volume%20method%20for%20three-dimensional%20diffusion%20problem | Finite volume method (FVM) is a numerical method. FVM in computational fluid dynamics is used to solve the partial differential equation which arises from the physical conservation law by using discretisation. Convection is always followed by diffusion and hence where convection is considered we have to consider combine effect of convection and diffusion. But in places where fluid flow plays a non-considerable role we can neglect the convective effect of the flow. In this case we have to consider more simplistic case of only diffusion. The general equation for steady convection-diffusion can be easily derived from the general transport equation for property by deleting transient.
General transport equation is defined as:
…………………………………………….1
Where,
is a conservative form of all fluid flow,
is density,
is a net rate of flow of out of fluid element represents convective term,
is a transient term,
is a rate of change of due to diffusion,
is a rate of increase of due to source.
Due to steady state condition transient term becomes zero and due to absence of convection convective term becomes zero, therefore steady state three- dimensional convection and diffusion equation becomes:
………………………………………………………….2
Therefore,
…………………………………………………………………….3
Flow should also satisfy continuity equation therefore,
………………………………………………………………………………………………………4
To solve the problem we will follow following general steps
Grid formation:
1. Divide the domain into discrete control volume.
2. Place the nodal point between end points defining the physical boundaries. Boundaries/ faces of the control volume are created midway between adjacent nodes.
3. Set up the control volume near the edge of domain such that physical as well as control volume boundaries will coincide with each other.
4. Considering a general nodal point P accompanied by six neighboring nodal point ‘E’ (which represent east), ‘W’ (which represent west), ‘N’ (which represent north), ‘S’ (which represent south), ‘T’ (which represent Top), ‘B’ (which represent bottom). In the considered control volume east side face is referred by ‘e’, west side face is referred by ‘w’, north side face is referred by ‘n’, south side face is referred by ‘s’, top side face is referred by ‘t’, bottom side face is referred by ‘b’.
5. Now the distance between nodes W and P, between nodes P and E, between nodes P and N, between nodes S and P, between nodes P and T, between nodes B and P are denoted as respectively.
Discretisation:
On integration of equation 3 in one dimension over the general control volume gives:
[
Now using central differencing method we can rewrite above equation as
[
This can be rearranged to give the discretised equation for interior nodes:
Where
Solution of equation:
1. For solving the one- dimensional convection- diffusion problem we have to express equation (8) at all the grid nodes.
2. Now obtained set of algebraic equations is then solved to obtain the distribution of the transported property .
See also
Finite volume method
Computational fluid dynamics
Finite volume method for one-dimensional steady state diffusion
Convection
Control volume
Central differencing scheme
External links
http://mathworld.wolfram.com/FiniteVolumeMethod.html
The finite volume method by R. Eymard, T Gallouët and R. Herbin, update of the article published in Handbook of Numerical Analysis, 2000
https://web.archive.org/web/20140210101323/http://s6.aeromech.usyd.edu.au/aero/cvanalysis/integral_approach.pdf
http://www.phy.davidson.edu/fachome/dmb/py200/centraldiff.htm
http://opencourses.emu.edu.tr/course/view.php?id=27&lang=en
References
Computational fluid dynamics
Mathematical problems | Finite volume method for three-dimensional diffusion problem | [
"Physics",
"Chemistry",
"Mathematics"
] | 907 | [
"Computational fluid dynamics",
"Fluid dynamics",
"Mathematical problems",
"Computational physics"
] |
44,476,398 | https://en.wikipedia.org/wiki/Nitrogen-15%20nuclear%20magnetic%20resonance%20spectroscopy | Nitrogen-15 nuclear magnetic resonance spectroscopy (nitrogen-15 NMR spectroscopy, or just simply 15N NMR) is a version of nuclear magnetic resonance spectroscopy that examines samples containing the 15N nucleus. 15N NMR differs in several ways from the more common 13C and 1H NMR. To circumvent the difficulties associated with measurement of the quadrupolar, spin-1 14N nuclide, 15N NMR is employed in samples for detection since it has a ground-state spin of ½. Since14N is 99.64% abundant, incorporation of 15N into samples often requires novel synthetic techniques.
Nitrogen-15 is frequently used in nuclear magnetic resonance spectroscopy (NMR), because unlike the more abundant nitrogen-14, that has an integer nuclear spin and thus a quadrupole moment, 15N has a fractional nuclear spin of one-half, which offers advantages for NMR like narrower line width. Proteins can be isotopically labeled by cultivating them in a medium containing nitrogen-15 as the only source of nitrogen. In addition, nitrogen-15 is used to label proteins in quantitative proteomics (e.g. SILAC).
Implementation
15N NMR has complications not encountered in 1H and 13C NMR spectroscopy. The 0.36% natural abundance of 15N results in a major sensitivity penalty. Sensitivity is made worse by its low gyromagnetic ratio (γ = −27.126 × 106 T−1s−1), which is 10.14% that of 1H. The signal-to-noise ratio for 1H is about 300-fold greater than 15N at the same magnetic field strength.
Physical properties
The physical properties of 15N are quite different from other nuclei. Its properties along with several common nuclei are summarized in the below table.
From these data, one can see that at full enrichment, 15N is about one tenth (-27.126/267.522) as sensitive as 1H.
Chemical shift trends
The International Union of Pure and Applied Chemistry (IUPAC) recommends using CH3NO2 as the experimental standard; however in practice many spectroscopists utilize pressurized NH3(l) instead. For 15N, chemical shifts referenced with NH3(l) are 380.5 ppm upfield from CH3NO2 (δNH3 = δCH3NO2 + 380.5 ppm). Chemical shifts for 15N are somewhat erratic but typically they span a range of -400 ppm to 1100 ppm with respect to CH3NO2. Below is a summary of 15N chemical shifts for common organic groups referenced with respect to NH3, whose chemical shift is assigned 0 ppm.
Gyromagnetic ratio
Unlike most nuclei, the gyromagnetic ratio for 15N is negative. With the spin precession phenomenon, the sign of γ determines the sense (clockwise vs counterclockwise) of precession. Most common nuclei have positive gyromagnetic ratios such as 1H and 13C.
Applications
Tautomerization
15N NMR is used in a wide array of areas from biological to inorganic techniques. A famous application in organic synthesis is to utilize 15N to monitor tautomerization equilibria in heteroaromatics because of the dramatic change in 15N shifts between tautomers.
Protein NMR
15N NMR is also extremely valuable in protein NMR investigations. Most notably, the introduction of three-dimensional experiments with 15N lifts the ambiguity in 13C–13C two-dimensional experiments. In solid-state nuclear magnetic resonance (ssNMR), for example, 15N is most commonly utilized in NCACX, NCOCX, and CANcoCX pulse sequences.
Investigation of nitrogen-containing heterocycles
15N NMR is the most effective method for investigation of structure of heterocycles with a high content of nitrogen atoms (tetrazoles, triazines and their annelated analogs). 15N labeling followed by analysis of 13C–15N and 1H–15N couplings may be used for establishing structures and chemical transformations of nitrogen heterocycles.
INEPT
Insensitive nuclei enhanced by polarization transfer (INEPT) is a signal resolution enhancement method. Because 15N has a gyromagnetic ratio that is small in magnitude, the resolution is quite poor. A common pulse sequence which dramatically improves the resolution for 15N is INEPT. The INEPT is an elegant solution in most cases because it increases the Boltzmann polarization and lowers T1 values (thus scans are shorter). Additionally, INEPT can accommodate negative gyromagnetic ratios, whereas the common nuclear Overhauser effect (NOE) cannot.
See also
Heteronuclear single quantum coherence spectroscopy (HSQC)
Two-dimensional nuclear magnetic resonance spectroscopy
Triple-resonance nuclear magnetic resonance spectroscopy
References
Nuclear magnetic resonance | Nitrogen-15 nuclear magnetic resonance spectroscopy | [
"Physics",
"Chemistry"
] | 1,018 | [
"Nuclear magnetic resonance",
"Nuclear physics"
] |
44,476,643 | https://en.wikipedia.org/wiki/AnTuTu | AnTuTu () is a software benchmarking tool commonly used to benchmark smartphones and other devices. It is owned by Chinese company Cheetah Mobile.
Operations
The company developing the software is based in Chaoyang District, Beijing, and was cofounded by Chinese entrepreneurs Shào Yīng (邵英) and Liáng Bīn (梁斌). They started multi-platform development, releasing an x86 Linux version in May 2021 and a Windows version with ray tracing support in August 2021.
Circumvention
The AnTuTu benchmark is so common that some hardware manufacturers have cheated on the benchmark, which made the benchmark unreliable. In response to cheating, AnTuTu created a new benchmark, called AnTuTu X, which made it more difficult for manufacturers to cheat on the benchmark.
Despite the changes introduced by AnTuTu X, cheating continued to be rampant; for instance, in 2021, AnTuTu delisted (and for three months, banned) the Realme GT after evidence was discovered that the phone was found to have used delay tactics in multithreading performance tests, as well as modifying the reference JPEG image for image processing tests.
Versions
Versions of AnTuTu
Notes
AnTuTu maintains rankings for devices by parameters (CPU, GPU, RAM, UX, total), SoC (only Android; by CPU and GPU), and AI performance (only Android).
AnTuTu (mainland China) maintains rankings for Android devices total (standard version and lite version), SoC total, SoC AI total, positive rating and Android device cost effectiveness (¥4000 and above, ¥3000-¥3999, ¥2000-¥2999, ¥1000-¥1999 and below ¥999). Device total and positive rating for both iPhone and iPad. Vehicle total and SoC total for vehicle head unit. Clicking on any device name does not give extra details, instead it links to jd.com for easy purchase.
Scores obtained on Android and iOS cannot be compared directly due to differences in operating systems: core architecture, different programming languages, and graphical APIs.
References
External links
Benchmarks (computing)
Chinese brands
Companies based in Beijing
Privately held companies of China | AnTuTu | [
"Technology"
] | 461 | [
"Benchmarks (computing)",
"Computing comparisons",
"Computer performance"
] |
62,105,397 | https://en.wikipedia.org/wiki/Lofoten%20Declaration | The Lofoten Declaration, drafted in August 2017, is an international manifesto calling for the end of hydrocarbon exploration and further expansion of fossil fuel reserves for climate change mitigation. It calls for fossil fuel divestment and phase-out of use with a just transition to a low-carbon economy. A diverse group of signatories has signed the declaration, affirming demands for early leadership in efforts from the economies that have benefited the most from fossil fuel extraction. The Declaration was named for the Lofoten archipelago where public concern has successfully prevented offshore development of petroleum reserves.
Signed by 600 organizations spanning 76 countries, the Declaration is believed to have helped influence the government of Norway to divest from investment in exploration and production.
The Lofoten Declaration also helped mobilize efforts for a global treaty on a managed decline of fossil fuel production, such as the Fossil Fuel Non-Proliferation Treaty Initiative.
References
Climate action plans
Emissions reduction
Climate change policy
Ethical investment
Low-carbon economy
Sustainable energy | Lofoten Declaration | [
"Chemistry"
] | 202 | [
"Greenhouse gases",
"Emissions reduction"
] |
62,105,550 | https://en.wikipedia.org/wiki/Green%20border | A green border is a weakly protected section of the national border. The term green border comes from the area covered with vegetation: green borders are usually forests, thickets and meadows, often with varied terrain.
The act of (illegal) crossing to
the green border is associated with the phenomenon of smuggling goods and persons of a criminal nature, but it has sometimes also been politically motivated. Green borders are and have been crossed by participants of the political activists illegally operating in their countries to contact with foreign collaborators, allies, emigres and the like, or to emigrate and seek refuge.
Green border in Schengen zone
Green borders exist within the European Union as the state borders internal to the European Union, crossed by tourists outside the area of former border crossings. After the Schengen Agreement became effective, crossing borders between countries where the agreement applies is allowed at every section of the border. Article 22 of the Schengen Borders Code mentions this. Only persons without EU citizenship who do not have a visa to enter the whole territory are excluded from this regulation.
References
External links
International border crossings
Borders | Green border | [
"Physics"
] | 221 | [
"Spacetime",
"Borders",
"Space"
] |
62,108,776 | https://en.wikipedia.org/wiki/Edward%20Anders | Edward Anders (born June 21, 1926) is a Latvian-born American chemist and emeritus professor of chemistry at the University of Chicago. His major areas of research have included the origin and ages of meteorites, the existence of presolar grains in meteorites, the solar-system abundance of chemical elements, and mass extinctions in earth history. In the 1970s, he was one of the 142 principal investigators who studied lunar samples brought back to Earth by the Apollo program. After retiring from scientific research in 1991, he became a prominent researcher, speaker and writer on issues related to the Holocaust in Latvia.
Early life and education
Anders was born Edward Alperovitch in the Latvian coastal city of Liepāja in 1926. Both his mother (Erica, née Sheftelovitch-Meiran) and his father (Adolf) were part of a German-speaking Jewish merchant community. In 1940, the Soviet Union occupied Latvia, and in 1941, Latvia was invaded by Nazi Germany. Anders's father was among many Liepaja Jews murdered by the Nazis in the early months of the occupation. Anders and his mother evaded Nazi annihilation by pretending that she was an Aryan foundling raised by Jews, until they were able to flee Latvia near the end of World War II.
After the end of the war, Anders settled in Munich, where he attended first the UNRRA University, a makeshift institution created by the United Nations Relief and Rehabilitation Administration solely to serve refugees, and then the University of Munich. In August 1948, Anders appeared as a prosecution witness at the Nuremberg High Command Trial, where he gave evidence of German soldiers carrying out lootings and shooting Jewish civilians in Liepaja during 1941.
In 1949, Anders arrived in New York City, where he embarked on a master's degree in chemistry at Columbia University. He earned a Ph.D. from Columbia in 1954, benefiting from the mentorship of Columbia nuclear-chemistry professor Jack Malcolm Miller.
Career
Anders spent most of his scientific career on the chemistry faculty at the University of Chicago. He arrived as an assistant professor in 1955, gained tenure a few years later and was named the Horace B. Horton professor in 1973. He spent 1963–64 at the University of Bern as a visiting professor on sabbatical; he returned to the Swiss university for six shorter stays from 1970–1990. His first academic appointment was as an instructor at the University of Illinois (Champaign-Urbana) from 1954 to 1955.
In 1959, Anders won the Newcomb Cleveland Prize from the American Association for the Advancement of Science for his work on meteorites and asteroids. His findings during this period included evidence that meteorites come from the asteroid belt, and an explanation for the ways tiny diamonds could be created in meteorites, without requiring the enormous pressure that could only be found in larger bodies with greater gravitational forces.
In 1973, Anders received the NASA Exceptional Scientific Achievement Medal, acknowledging his work analyzing multiple batches of lunar samples brought back to Earth by the Apollo project. In 1974, Britain's Royal Astronomical Society named him an honorary foreign member, or associate. He also was elected to the U.S. National Academy of Sciences in 1974.
Anders and colleagues began documenting evidence of stardust within meteorites in 1978, publishing findings in Science suggesting that "primitive meteorites contain yet another kind of alien, presolar material: dust grains ejected from red giants." Subsequent research by Anders and coworkers established the presence of diamonds, silicon carbide and graphite in meteorites' interstellar grains. In a 1991 interview with Discover, Anders referred to meteorites as "the poor man's space probe."
In the 1980s, Anders and colleagues published evidence in Science and Nature of catastrophic fires 65 million years ago, caused by a giant meteorite crash in the Gulf of Mexico. Their research on the Cretaceous–Paleogene extinction event analyzed silt sediments from sites as far away as Europe and New Zealand. In each case, they found high amounts of iridium (a rare element associated with certain meteorites) and massive amounts of carbon (associated with global fires) in the same layers. "The first year after the impact was a dramatic and dangerous period for life on Earth," Anders told The New York Times.
In 1989, Anders and Belgian astronomer Nicolas Grevesse published "Abundances of the Elements," a scientific paper cataloging the most reliable estimates to date of meteorite and solar abundances of more than 80 elements, ranging from hydrogen to uranium. Their findings have been cited in more than 11,000 subsequent papers by other scientific researchers, according to Google Scholar.
Holocaust research
In 2003, Anders and co-author Juris Dubrovskis published "Who Died in the Holocaust? Recovering Names From Official Records." Their article, which appeared in Holocaust & Genocide Studies, used Latvian, German, Israeli and other records to document the fate of each of Liepaja's 7,140 Jewish residents during Nazi Germany's occupation. Anders and Dubrovskis established that only 208 survived.
In 2004, Latvia's president, Vaira Vīķe-Freiberga, spoke at the dedication of a Holocaust memorial in Liepāja. She closed by saying: "I want to thank the Liepāja Holocaust Memorial Committee, its chairman Mr. Edward Anders, Mr. Vladimirs Bāns, the authors of the project, and all who lent a hand to make this Memorial become reality."
References
1926 births
Living people
University of Chicago faculty
Scientists from Liepāja
Columbia Graduate School of Arts and Sciences alumni
Members of the United States National Academy of Sciences
Fellows of the American Academy of Arts and Sciences
Fellows of the American Association for the Advancement of Science
American historians of the Holocaust
20th-century Latvian Jews
Jewish American historians
Jewish American scientists
Jewish American non-fiction writers
20th-century American male writers
20th-century American non-fiction writers
21st-century American male writers
21st-century American non-fiction writers
21st-century American historians
American geochemists
Latvian chemists
Soviet emigrants to the United States
20th-century American chemists
Latvian people of German descent
Latvian expatriates in Germany
American planetary scientists
Recipients of the V. M. Goldschmidt Award | Edward Anders | [
"Chemistry"
] | 1,258 | [
"Geochemists",
"Recipients of the V. M. Goldschmidt Award",
"American geochemists"
] |
62,110,745 | https://en.wikipedia.org/wiki/Bofedales | Bofedales (singular bofedal), known in some parts of Peru as oconales, are a type of wetland found in the Andes. They are a feature in the land use and ecology of high Andean ecosystems. They form in flat areas around ponds or streams and may be permanent or seasonal, and they can be man made or natural. Bofedales are associated with organic material in the soil and their green colour often contrasts with that of the drier surrounding landscape.
They are found at elevations exceeding above sea level. Bofedales absorb the limited amount of water derived from snow, glacier meltwater and rain showers, storing it in ground and slowly releasing it. Their vegetation is dominated by cushion plants. Numerous animals including birds, mammals and invertebrates occur in bofedales. They are used by humans, who have created new such wetlands through irrigation, but human activities can also be a threat to these ecosystems.
Name and classification
is the singular term; the plural is . The Quechua languages have terms like , , and , while the Aymara language terms are and ; there are also spelling variants. refers to wetlands, which frequently but not always are bofedales. The term "bofedal"/"bofedales" is frequently used for other types of wetlands or Andean ecosystems that do not need the definition.
Characteristics
Bofedales are wetlands featuring cushion plants in the Andes between Colombia and Venezuela in the north to Patagonia in the south. The surrounding drier, yellow landscape contrasts notably with the green bofedales, creating landscapes of great aesthetic value. The tropical Andes feature numerous vegetation zones, with the páramo in the north having the highest humidity. To the south moisture decreases and the distinction between the wet season and dry season increases, yielding the transition from the páramo to the jalca vegetation and finally to the puna grassland. The Puna contains both xerophytic and wet sections. Analogous ecosystems exist in the mountains of East Africa, Hawaii and New Guinea.
The landscape of a bofedal features ponds, lawns and hummocks. Plants growing in bofedales form cushions, meadows, shrubs or flat-growing forms. The bofedales can reach sizes of more than or less than . In Chile, long and narrow bofedales form at the bottom of valleys. They usually form on flat terrain, next to ponds, springs and streams, but most of the water is underground. The water originates as groundwater or from rivers, lakes and glaciers and is only slowly released by the bofedales, which thus constitute important water stores for the dry season, allowing streams to continue flowing. Almost all river systems in southern Peru have bofedales in their headwaters.
The climate conditions are often extreme, featuring high insolation and strong winds, lack of precipitation and oxygen due to the thin atmosphere at these elevations, low temperatures with daily frosts and a short growing season. Bofedales sometimes exist only seasonally, others are present year-round. They feature peat or organic soils that can store significant quantities of carbon, equivalent to ten times that of normal Sphagnum peat. They retain and filter nutrients. Sometimes the ground is so soft that animals can sink into it. Where bofedales have been dated, such as in Chile, they began development during the Holocene after deglaciation and often only during the last few millennia (including the Little Ice Age), when conditions became wetter.
Occurrence
, almost of Peru were covered by bofedales; this is about 0.4% of the country. Remote sensing found that in 1992–1993 about 1.4% of the Altiplano, about , were bofedales. In Chile large swathes of the Altiplano in the regions of Arica y Parinacota and Tarapacá are covered by bofedales. Relative to this region bofedales in the more arid Antofagasta Region are smaller and more isolated. The southernmost bofedales of the Central Andes are found at the latitude of the Nevado Tres Cruces National Park in Chile. In Peru, most bofedales lie in glacial basins.
Flora and fauna
The most important plant species in bofedales are cushion plants, including the Juncaceae Distichia muscoides and Oxychloe andina. About 61 to 62 different plant species have been recorded in Central Andean bofedales. They do not occur in every bofedal; species composition varies between regions and different parts of the same bofedal. The species composition may vary due to grazing pressure and seed dispersal by animals, water availability and temperature, the presence of nutrients and toxic elements, and different stages of the ecological succession. Many of these plant species are endemic. Bofedales have a high biological productivity, the highest of all ecosystems in the Puna.
The water of bofedales provides habitats to amphibians like frogs (Acancocha water frog, common marsupial frogs and Pleurodema marmoratum) and toads (Rhinella spinulosa). Numerous invertebrates like annelids, crustaceans, insects, planarians and snails live in bofedales. Birds living in bofedales include Andean geese, Andean lapwings, Andean negritos, buff-winged cinclodes, crested ducks, Darwin's rheas, golden-spotted ground doves, grey-breasted seedsnipes and yellow-billed teals. The food resources of bofedales also draw mammals like Andean deer, Andean foxes, guanacos, various species of mice, pampas cats, pumas, white-tailed deer, vicuñas and vizcachas.
Human use
Bofedales are an important economic resource. At their elevations climatic conditions make agriculture unfeasible, while the high quality of the forage in bofedales invites animal husbandry. On the Altiplano, in drier areas they are the most important pasture. Alpacas, cattle, horses, llamas and sheep are fed there. Plants used in medicine or in spiritual activities are taken from bofedales.
Bofedales can be artificial, and many may have formed through the irrigation of pastures. Some bofedales are artificially created and sustained through irrigation to this day. Many more are at least partially modified by human activity. The Aymara, Quechua and Colla peoples have maintained traditional knowledge about the bofedales including irrigation techniques, animal rotation and the use of fire to remove dry plants. The human engineering of bofedales is poorly studied.
The water supply of Chilean cities in Atacama Desert such as Antofagasta and Calama has been, in part, historically derived from rivers tapped near bofedales. However studies show that in the early 1990s 62% of bofedales and bofedal-like vegas in northern Chile yielded water of questionable quality for human consumption. Issues related to the water quality of bofedales include the ocurrence of fecal and non-fecal coliform bacteria as well as fly eggs. A limited number of bofedales that function as water sources have had their drainage improved by channels due to sanitary reasons.
Threats and conservation
The use of bofedales for pasture frequently results in overgrazing, although it may not always be detrimental to bofedal function. More localized threats to bofedales are mining and the extraction of peat, which can result in severe damage. Other infrastructure projects threatening bofedales are dams, road projects, and the diversion of their water sources. Climate change is a further threat to these ecosystems as decreased precipitation and glacier retreat reduces the flow of water into bofedales, which is necessary to sustain them. Whether the activities of local communities are a threat or a benefit to bofedales is unclear.
Bofedales are biodiversity hotspots, and many of the animal species living in them are threatened. Bofedales are important ecosystems in the mountains, with high levels of species diversity and endemism, and their ability to retain water reduces erosion and maintains water resources. Within the Ramsar Convention, they are counted as unforested peatlands. Some bofedales are included in protected areas but , none were the subject of a dedicated protected area. They are considered to be vulnerable ecosystems under Peruvian environmental law. In Chile, some regions require special permissions to withdraw water from bofedales and their watersheds.
Gallery
See also
Dispute over the Status and Use of the Waters of the Silala, a case at the International Court of Justice about the Silala River
Fell
Mallín
Notes
References
Sources
Ecology of the Andes
Ecosystems
Marshes | Bofedales | [
"Biology"
] | 1,771 | [
"Symbiosis",
"Ecosystems"
] |
62,112,877 | https://en.wikipedia.org/wiki/Dependent%20random%20choice | In mathematics, dependent random choice is a probabilistic technique that shows how to find a large set of vertices in a dense graph such that every small subset of vertices has many common neighbors. It is a useful tool to embed a graph into another graph with many edges. Thus it has its application in extremal graph theory, additive combinatorics and Ramsey theory.
Statement of theorem
Let , and suppose:
Every graph on vertices with at least edges contains a subset of vertices with such that for all with , has at least common neighbors.
Proof
The basic idea is to choose the set of vertices randomly. However, instead of choosing each vertex uniformly at random, the procedure randomly chooses a list of vertices first and then chooses common neighbors as the set of vertices. The hope is that in this way, the chosen set would be more likely to have more common neighbors.
Formally, let be a list of vertices chosen uniformly at random from with replacement (allowing repetition). Let be the common neighborhood of . The expected value of isFor every -element subset of , contains if and only if is contained in the common neighborhood of , which occurs with probability An is bad if it has less than common neighbors. Then for each fixed -element subset of , it is contained in with probability less than . Therefore by linearity of expectation, To eliminate bad subsets, we exclude one element in each bad subset. The number of remaining elements is at least , whose expected value is at least Consequently, there exists a such that there are at least elements in remaining after getting rid of all bad -element subsets. The set of the remaining elements expresses the desired properties.
Applications
Turán numbers of a bipartite graph
Dependent random choice can help find the Turán number. Using appropriate parameters, if is a bipartite graph in which all vertices in have degree at most , then the extremal number where only depends on .
Formally, with , let be a sufficiently large constant such that If then
and so the assumption of dependent random choice holds. Hence, for each graph with at least edges, there exists a vertex subset of size satisfying that every -subset of has at least common neighbors. By embedding into by embedding into arbitrarily and then embedding the vertices in one by one, then for each vertex in , it has at most neighbors in , which shows that their images in have at least common neighbors. Thus can be embedded into one of the common neighbors while avoiding collisions.
This can be generalized to degenerate graphs using a variation of dependent random choice.
Embedding a 1-subdivision of a complete graph
DRC can be applied directly to show that if is a graph on vertices and edges, then contains a 1-subdivision of a complete graph with vertices. This can be shown in a similar way to the above proof of the bound on Turán number of a bipartite graph.
Indeed, if we set , we have (since )and so the DRC assumption holds. Since a 1-subdivision of the complete graph on vertices is a bipartite graph with parts of size and where every vertex in the second part has degree two, the embedding argument in the proof of the bound on Turán number of a bipartite graph produces the desired result.
Variation
A stronger version finds two subsets of vertices in a dense graph so that every small subset of vertices in has a lot of common neighbors in .
Formally, let be some positive integers with , and let be some real number. Suppose that the following constraints hold:
Then every graph on vertices with at least edges contains two subsets of vertices so that any vertices in have at least common neighbors in .
Extremal number of a degenerate bipartite graph
Using this stronger statement, one can upper bound the extremal number of -degenerate bipartite graphs: for each -degenerate bipartite graph with at most vertices, the extremal number is at most
Ramsey number of a degenerate bipartite graph
This statement can be also applied to obtain an upper bound of the Ramsey number of a degenerate bipartite graphs. If is a fixed integer, then for every bipartite -degenerate bipartite graph on vertices, the Ramsey number is of the order
References
Further reading
Dependent Random Choice - MIT Math
Extremal graph theory
Probabilistic arguments | Dependent random choice | [
"Mathematics"
] | 894 | [
"Mathematical relations",
"Graph theory",
"Extremal graph theory"
] |
62,114,488 | https://en.wikipedia.org/wiki/Zehra%20Sayers | Zehra Sayers (born 25 September 1953) is a Turkish-British structural biologist. She has previously served as Interim President of the Sabancı University (February–November 2018) and co-chaired the scientific advisory committee for Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME). She was part of a five-scientist group that received the AAAS Award for Science Diplomacy in 2019. She holds Turkish and British citizenship.
Early life and education
Sayers was born in Turkey. She studied physics at Boğaziçi University in Istanbul. For her postgraduate studies Sayers moved to the United Kingdom. In 1978 she earned a doctorate for research done at King's College London GKT School of Medical Education, the degree was awarded by the University of London. Sayers worked as a postdoctoral researcher in the Open University and the Wallenberg Laboratory, Uppsala University. In 1986 she was the first woman staff scientist to be appointed to the Hamburg outstation of the European Molecular Biology Laboratory, where she used synchrotron radiation to study cytoskeletal proteins and chromatin. Whilst working in Germany she obtained her habilitation in 1996 with a thesis from the University of Hamburg.
Research and career
In 1998 Sayers returned to Turkey, joining the founding faculty of Sabancı University as the partner of Ahmet Evin. Established by the Turkish industrial and financial conglomerate Hacı Ömer Sabancı Holding A.Ş., Sabancı University was the first and only university where Sayers served as faculty member: she was Director of the Foundation Development Program in 2010 and Interim President from February to November 2018. Her research has considered recombinant protein production, and has considered the structure of chromatin fibres and filamentous proteins. She looks to identify the relationship between structure and function in macromolecules. At Sabancı University, Sayers was involved in undergraduate teaching, developing an interdisciplinary, liberal arts, curriculum for science teaching. She became professor emerita in 2022.
Sayers became involved with the Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME) project since 2000. The light source was inaugurated in 2017 by Abdullah II of Jordan. She believes that synchrotron light sources are an effective way to integrate scientists from different disciplines and nationalities. During her time as Co-chair of the Scientific Advisory Committee, more than 100 young scientists were trained to use the synchrotron radiation. She held her position as Co-chair of the Scientific Advisory Committee of SESAME from 2002 to 2018. Sayers has worked as an advisor for the Turkish Accelerator Center Project, supported by the Turkish state. Together with Eliezer Rabinovici, she spoke about the international collaborations that are part of SESAME at TEDxCERN in 2013.
Selected publications
Awards and honours
She was awarded the EuroScience Rammal Award in 2017, which recognised her contributions to building the scientific programme of SESAME. In 2019 Sayers became the first person of joint Turkish and British citizenship to win the AAAS Award for Science Diplomacy, as part of a group of five scientists receiving the award for their contributions to SESAME. Later that year she was named as one of the BBC 100 Women in 2019.
References
Living people
1953 births
Boğaziçi University alumni
Alumni of the University of London
Academic staff of Istanbul University
University of Hamburg alumni
Academic staff of Sabancı University
21st-century Turkish women scientists
21st-century Turkish scientists
Turkish women academics
Academics of the Open University
Structural biologists
Turkish biologists
Women biologists
Turkish emigrants to the United Kingdom | Zehra Sayers | [
"Chemistry"
] | 737 | [
"Structural biologists",
"Structural biology"
] |
62,117,133 | https://en.wikipedia.org/wiki/Gradient%20vector%20flow | Gradient vector flow (GVF), a computer vision framework introduced by Chenyang Xu and Jerry L. Prince, is the vector field that is produced by a process that smooths and diffuses an input vector field. It is usually used to create a vector field from images that points to object edges from a distance. It is widely used in image analysis and computer vision applications for object tracking, shape recognition, segmentation, and edge detection. In particular, it is commonly used in conjunction with active contour model.
Background
Finding objects or homogeneous regions in images is a process known as image segmentation. In many applications, the locations of object edges can be estimated using local operators that yield a new image called an edge map. The edge map can then be used to guide a deformable model, sometimes called an
active contour or a snake, so that it passes through the edge map in a smooth way, therefore defining the object itself.
A common way to encourage a deformable model to move toward the edge map is to take the spatial gradient of the edge map, yielding a vector field. Since the edge map has its highest intensities directly on the edge and drops to zero away from the edge, these gradient vectors provide directions for the active contour to move. When the gradient vectors are zero, the active contour will not move, and this is the correct behavior when the contour rests on the peak of the edge map itself. However, because the edge itself is defined by local operators, these gradient vectors will also be zero far away from the edge and therefore the active contour will not move toward the edge when initialized far away from the edge.
Gradient vector flow (GVF) is the process that spatially extends the edge map gradient vectors, yielding a new vector field that contains
information about the location of object edges throughout the entire image domain. GVF is defined as a diffusion process operating on the
components of the input vector field. It is designed to balance the fidelity of the original vector field, so it is not changed too much,
with a regularization that is intended to produce a smooth field on its output.
Although GVF was designed originally for the purpose of segmenting objects using active contours attracted to edges, it has been since
adapted and used for many alternative purposes. Some newer purposes including defining a continuous medial axis representation, regularizing image anisotropic diffusion algorithms, finding the centers of ribbon-like objects, constructing graphs for optimal surface segmentations, creating a shape prior, and much more.
Theory
The theory of GVF was originally described by Xu and Prince. Let be an edge map defined on the image domain. For uniformity of results, it is important to restrict the edge map intensities to lie between 0 and 1, and by convention takes on larger values (close to 1) on the object edges. The gradient vector flow (GVF) field is given by the vector field that minimizes the energy functional
In this equation, subscripts denote partial derivatives and the gradient of the edge map is given by the vector field
. Figure 1 shows an edge map, the gradient
of the (slightly blurred) edge map, and the GVF field generated by
minimizing .
Equation 1 is a variational formulation that has both a data term and a regularization term. The first term in the integrand is the data term. It encourages the solution to closely agree with the gradients of the edge map since that will make
small. However, this only needs to happen when the edge map gradients are large since
is multiplied by the square of the length of these gradients. The second term in the integrand is a regularization term. It encourages the spatial variations in the components of the solution to be small by penalizing the sum of all the partial
derivatives of . As is customary in these types of variational formulations, there is a regularization parameter
that must be specified by the user in order to trade off the influence of each of the two terms.
If is large, for example, then the resulting field will be very smooth and may not agree as well
with the underlying edge gradients.
Theoretical Solution. Finding to minimize Equation 1
requires the use of calculus of variations since is a function, not a
variable. Accordingly, the Euler equations, which provide the necessary conditions for
to be a solution can be found by calculus of variations, yielding
where is the Laplacian operator. It is instructive to examine the form of the equations in (2). Each is a partial differential equation that the components and of must satisfy. If the magnitude of the edge gradient is small, then the solution of each equation is guided entirely by Laplace's equation, for example , which will produce a smooth scalar field entirely dependent on its boundary conditions. The boundary conditions are effectively provided by the locations in the image where the magnitude of the edge gradient is large, where the solution is driven to agree more with the edge gradients.
Computational Solutions. There are two fundamental ways to compute GVF. First, the energy function
itself (1) can be directly discretized and minimized, for example, by gradient descent. Second, the partial
differential equations in (2) can be discretized and solved iteratively. The original GVF paper used an iterative
approach, while later papers introduced considerably faster implementations such as an octree-based method,
a multi-grid method, and an augmented Lagrangian method. In addition, very fast GPU implementations have been developed in
Extensions and Advances. GVF is easily extended to higher dimensions. The energy function is readily written in a vector form as
which can be solved by gradient descent or by finding and solving its
Euler equation. Figure 2 shows an illustration of a three-dimensional GVF field on the edge map of a simple object (see ).
The data and regularization terms in the integrand of the GVF functional can also be modified. A modification described
in , called
generalized gradient vector flow (GGVF) defines two scalar functions and reformulates the energy as
While the choices and reduce GGVF to GVF,
the alternative choices and ,
for a user-selected constant, can improve the tradeoff between the data term and its regularization in some applications.
The GVF formulation has been further extended to vector-valued images in where a weighted structure tensor of a vector-valued image is used. A learning based probabilistic weighted GVF extension was proposed in to further improve the segmentation for images with severely cluttered textures or high levels of noise.
The variational formulation of GVF has also been modified in motion GVF (MGVF) to incorporate object motion in
an image sequence.
Whereas the diffusion of GVF vectors from a conventional edge map acts in an isotropic manner, the formulation of
MGVF incorporates the expected object motion between image frames.
An alternative to GVF called vector field convolution (VFC) provides many of the advantages of GVF, has superior noise robustness, and
can be computed very fast. The VFC field is defined as the convolution of the edge map with a vector field kernel
where
The vector field kernel has vectors that always point toward the origin but their magnitudes, determined in detail by the
function , decrease to zero with increasing distance from the origin.
The beauty of VFC is that it can be computed very rapidly using a fast Fourier transform (FFT), a multiplication, and an inverse FFT. The
capture range can be large and is explicitly given by the radius of the vector field kernel. A possible drawback of VFC is that weak
edges might be overwhelmed by strong edges, but that problem can be alleviated by the use of a hybrid method that switches to conventional
forces when the snake gets close to the boundary.
Properties. GVF has characteristics that have made it useful in many diverse applications. It has already been noted that
its primary original purpose was to extend a local edge field throughout the image domain, far away from the actual edge in many
cases. This property has been described as an extension of the capture range of the external force of an active contour
model. It is also capable of moving active contours into concave regions of an object's boundary. These two properties are illustrated
in Figure 3.
Previous forces that had been used as external forces (based on the edge map gradients and simply related variants) required pressure
forces in order to move boundaries from large distances and into concave regions. Pressure forces, also called balloon forces, provide
continuous force on the boundary in one direction (outward or inward), and tend to have the effect of pushing through
weak boundaries. GVF can often replace pressure forces and yield better performance in such situations.
Because the diffusion process is inherent in the GVF solution, vectors that point in opposite directions tend to compete as they meet at a
central location, thereby defining a type of geometric feature that is related to the boundary configuration, but not directly evident from
the edge map. For example, perceptual edges are gaps in the edge map which tend to be connected visually by human
perception.
GVF helps to connect them by diffusing opposing edge gradient vectors across the gap; and even though there
is no actual edge map, active contour will converge to the perceptual edge because the GVF vectors drive them there (see ).
This property carries over when there are so-called weak edges identified by regions of edge maps having lower values.
GVF vectors also meet in opposition at central locations of objects thereby defining a type of medialness. This property has been
exploited as an alternative definition of the skeleton of objects and also as a way to initialize deformable models within objects such that convergence to the boundary is more likely.
Applications
The most fundamental application of GVF is as an external force in a deformable model. A typical application considers an image
with an object delineated by intensity from its background. Thus, a suitable edge map
could be defined by
where is a Gaussian blurring kernel with standard deviation and is convolution. This definition is applicable in any dimension and yields an edge map that falls in the range . Gaussian blurring is used primarily so that a
meaningful gradient vector can always be computed, but is generally kept fairly small so that true edge positions are not overly
distorted. Given this edge map, the GVF vector field can be computed by solving (2).
The deformable model itself can be implemented in a variety of ways including parametric models such as the original
snake or active surfaces and implicit models including geometric deformable models. In the case
of parametric deformable models, the GVF vector field can be used directly as the external forces in the model.
If the deformable model is defined by the evolution of the (two-dimensional) active contour , then a simple
parametric active contour evolution equation can be written as
Here, the subscripts indicate partial derivatives and and
are user-selected constants.
In the case of geometric deformable models, then the GVF vector field is first projected against the normal direction of
the implicit wavefront, which defines an additional speed function. Accordingly, then the evolution of the signed distance function
defining a simple geometric deformable contour can be written as
where is the curvature of the contour and is a user-selected constant.
A more sophisticated deformable model formulation that combines
the geodesic active contour flow with GVF forces was proposed
in . This paper also shows how to apply the Additive
Operator Splitting schema for rapid computation of this segmentation method. The uniqueness and existence of this
combined model were proven in .
A further modification of this model by using an external force term minimizing GVF divergence was proposed in
to achieve even better segmentation for images with complex geometric objects.
GVF has been used to find both inner, central, and central cortical surfaces in the analysis of brain images, as shown in Figure 4. The
process first finds the inner surface using a three-dimensional geometric deformable model with conventional forces. Then the central
surface is found by exploiting the central tendency property of GVF. In particular, the cortical membership function of the human brain
cortex, derived using a fuzzy classifier, is used to compute GVF as if itself were a thick edge map. The computed GVF vectors point towards
the center of the cortex and can then be used as external forces to drive the inner surface to the central surface. Finally, another
geometric deformable model with conventional forces is used to drive the central surface to a position on the outer surface of the cortex.
Several notable recent applications of GVF include constructing graphs for optimal surface segmentation in spectral-domain optical coherence
tomography volumes, a learning based probabilistic GVF active contour formulation to give more weights to objects
of interest in ultrasound image segmentation, and an adaptive multi-feature GVF active contour
for improved ultrasound image segmentation without hand-tuned parameters.
Related concepts
Deformable models
Active contour model
Edge detection
References
Computer vision | Gradient vector flow | [
"Engineering"
] | 2,723 | [
"Artificial intelligence engineering",
"Packaging machinery",
"Computer vision"
] |
65,872,687 | https://en.wikipedia.org/wiki/List%20of%20vegetation%20types%20of%20South%20Africa | Listing of the diverse vegetation types of South Africa that have been sampled, classified, described, and mapped by the SANBI VEGMAP project. Vegetation types of Lesotho and Eswatini are included in the project. The vegetation map is useful for biodiversity assessment, research, conservation management and environmental planning, and includes a database. The project is ongoing as more data becomes available over time. The first map was published in 2006, and has been updated in 2009. 2012 and 2018.
The classification system uses a hierarchy to organise the vegetation types within the nine defined biomes and a tenth azonal group. Bioregions are described within the biomes, and the vegetation types are at the more detailed level, and represent groups of communities with similar biotic and abiotic features. The vegetation types are plotted on the map in as much resolution as is available using a GIS system.
Mapping of the distribution and extent of natural vegetation of South Africa started in 1918 when the Botanical Survey of the Union of South Africa was established. Maps by Pole-Evans (1936), Acocks (1953), and Low and Rebelo (1996) preceded the current system, which is the combined effort of participants from various centres in the country.
Listed by biome:
Savanna
88 Savanna vegetation types, code SV:
Andesite Mountain Bushveld (SVcb 11)
Aoub Duneveld (SVkd 3)
Barberton Serpentine Sourveld (SVl 13)
Bhisho Thornveld (SVs 7)
Cathedral Mopane Bushveld (SVmp 3)
Central Sandy Bushveld (SVcb 12)
Delagoa Lowveld (SVl 4)
Dwaalboom Thornveld (SVcb 1)
Dwarsberg-Swartruggens Mountain Bushveld (SVcb 4)
Eastern Valley Bushveld (SVs 6)
Gabbro Grassy Bushveld (SVl 6)
Gauteng Shale Mountain Bushveld (SVcb 10)
Ghaap Plateau Vaalbosveld (SVk 7)
Gold Reef Mountain Bushveld (SVcb 9)
Gordonia Duneveld (SVkd 1)
Gordonia Kameeldoring Bushveld (SVkd 2)
Gordonia Plains Shrubland (SVk 16)
Granite Lowveld (SVl 3)
Gravelotte Rocky Bushveld (SVl 7)
Kaalrug Mountain Bushveld (SVl 12)
Kathu Bushveld (SVk 12)
Kimberley Thornveld (SVk 4)
Koranna-Langeberg Mountain Bushveld (SVk 15)
Kuruman Mountain Bushveld (SVk 10)
Kuruman Thornveld (SVk 9)
Kuruman Vaalbosveld (SVk 8)
KwaZulu-Natal Hinterland Thornveld (SVs 3)
KwaZulu-Natal Sandstone Sourveld (SVs 5)
Lebombo Summit Sourveld (SVl 17)
Legogote Sour Bushveld (SVl 9)
Limpopo Ridge Bushveld (SVmp 2)
Limpopo Sweet Bushveld (SVcb 19)
Loskop Mountain Bushveld (SVcb 13)
Loskop Thornveld (SVcb 14)
Lowveld Rugged Mopaneveld (SVmp 6)
Madikwe Dolomite Bushveld (SVcb 2)
Mafikeng Bushveld (SVk 1)
Makatini Clay Thicket (SVl 21)
Makhado Sweet Bushveld (SVcb 20)
Makuleke Sandy Bushveld (SVl 1)
Malelane Mountain Bushveld (SVl 11)
Mamabolo Mountain Bushveld (SVcb 24)
Marikana Thornveld (SVcb 6)
Molopo Bushveld (SVk 11)
Moot Plains Bushveld (SVcb 8)
Mopane Basalt Shrubland (SVmp 4)
Mopane Gabbro Shrubland (SVmp 8)
Musina Mopane Bushveld (SVmp 1)
Ngongoni Veld (SVs 4)
Norite Koppies Bushveld (SVcb 7)
Northern Lebombo Bushveld (SVl 15)
Northern Zululand Sourveld (SVl 22)
Nossob Bushveld (SVkd 4)
Nwambyia-Pumbe Sandy Bushveld (SVl 2)
Ohrigstad Mountain Bushveld (SVcb 26)
Olifantshoek Plains Thornveld (SVk 13)
Phalaborwa-Timbavati Mopaneveld (SVmp 7)
Pilanesberg Mountain Bushveld (SVcb 5)
Polokwane Plateau Bushveld (SVcb 23)
Postmasburg Thornveld (SVk 14)
Poung Dolomite Mountain Bushveld (SVcb 25)
Pretoriuskop Sour Bushveld (SVl 10)
Roodeberg Bushveld (SVcb 18)
Schmidtsdrif Thornveld (SVk 6)
Schweizer-Reneke Bushveld (SVk 3)
Sekhukhune Mountain Bushveld (SVcb 28)
Sekhukhune Plains Bushveld (SVcb 27)
South Eastern Coastal Thornveld (SVs 8)
Southern Lebombo Bushveld (SVl 16)
Soutpansberg Mountain Bushveld (SVcb 21)
Springbokvlakte Thornveld (SVcb 15)
Stella Bushveld (SVk 2)
Swaziland Sour Bushveld (SVl 14)
Tembe Sandy Bushveld (SVl 18)
Thukela Thornveld (SVs 2)
Thukela Valley Bushveld (SVs 1)
Tsende Mopaneveld (SVmp 5)
Tshokwane-Hlane Basalt Lowveld (SVl 5)
Tzaneen Sour Bushveld (SVl 8)
Vaalbos Rocky Shrubland (SVk 5)
VhaVenda Miombo (SVcb 22)
Waterberg Mountain Bushveld (SVcb 17)
Western Maputaland Clay Bushveld (SVl 20)
Western Maputaland Sandy Bushveld (SVl 19)
Western Sandy Bushveld (SVcb 16)
Zeerust Thornveld (SVcb 3)
Zululand Coastal Thornveld (SVl 24)
Zululand Lowveld (SVl 23)
Grassveld
73 Grassveld vegetation types, code G:
Aliwal North Dry Grassland (Gh 2)
Amathole Mistbelt Grassland (Gd 2)
Amathole Montane Grassland (Gd 1)
Amersfoort Highveld Clay Grassland (Gm 13)
Barberton Montane Grassland (Gm 17)
Basotho Montane Shrubland (Gm 5)
Bedford Dry Grassland (Gs 18)
Besemkaree Koppies Shrubland (Gh 4)
Bloemfontein Dry Grassland (Gh 5)
Bloemfontein Karroid Shrubland (Gh 8)
Carletonville Dolomite Grassland (Gh 15)
Central Free State Grassland (Gh 6)
Drakensberg Afroalpine Heathland (Gd 10)
Drakensberg Foothill Moist Grassland (Gs 10)
Drakensberg-Amathole Afromontane Fynbos (Gd 6)
East Griqualand Grassland (Gs 12)
Eastern Free State Clay Grassland (Gm 3)
Eastern Free State Sandy Grassland (Gm 4)
Eastern Highveld Grassland (Gm 12)
Egoli Granite Grassland (Gm 10)
Frankfort Highveld Grassland (Gm 6)
Income Sandy Grassland (Gs 7)
Ithala Quartzite Sourveld (Gs 2)
KaNgwane Montane Grassland (Gm 16)
Karoo Escarpment Grassland (Gh 1)
Klerksdorp Thornveld (Gh 13)
KwaZulu-Natal Highland Thornveld (Gs 6)
Leolo Summit Sourveld (Gm 20)
Lesotho Highland Basalt Grassland (Gd 8)
Low Escarpment Moist Grassland (Gs 3)
Lydenburg Montane Grassland (Gm 18)
Lydenburg Thornveld (Gm 21)
Mabela Sandy Grassland (Gs 13)
Midlands Mistbelt Grassland (Gs 9)
Mooi River Highland Grassland (Gs 8)
Mthatha Moist Grassland (Gs 14)
Northern Drakensberg Highland Grassland (Gd 5)
Northern Escarpment Afromontane Fynbos (Gm 24)
Northern Escarpment Dolomite Grassland (Gm 22)
Northern Escarpment Quartzite Sourveld (Gm 23)
Northern Free State Shrubland (Gm 7)
Northern KwaZulu-Natal Moist Grassland (Gs 4)
Northern KwaZulu-Natal Shrubland (Gs 5)
Northern Zululand Mistbelt Grassland (Gs 1)
Paulpietersburg Moist Grassland (Gm 15)
Queenstown Thornveld (Gs 16)
Rand Highveld Grassland (Gm 11)
Sekhukhune Montane Grassland (Gm 19)
Senqu Montane Shrubland (Gm 2)
Southern Drakensberg Highland Grassland (Gd 4)
Southern KwaZulu-Natal Moist Grassland (Gs 11)
Soutpansberg Summit Sourveld (Gm 28)
Soweto Highveld Grassland (Gm 8)
Steenkampsberg Montane Grassland (GM 30)
Stormberg Plateau Grassland (Gd 3)
Strydpoort Summit Sourveld (Gm 27)
Tarkastad Montane Shrubland (Gs 17)
Tsakane Clay Grassland (Gm 9)
Tsomo Grassland (Gs 15)
uKhahlamba Basalt Grassland (Gd 7)
Vaal Reefs Dolomite Sinkhole Woodland (Gh 12)
Vaal-Vet Sandy Grassland (Gh 10)
Vredefort Dome Granite Grassland (Gh 11)
Wakkerstroom Montane Grassland (Gm 14)
Waterberg-Magaliesberg Summit Sourveld (Gm 29)
Western Free State Clay Grassland (Gh 9)
Western Highveld Sandy Grassland (Gh 14)
Western Lesotho Basalt Shrubland (Gd 9)
Winburg Grassy Shrubland (Gh 7)
Wolkberg Dolomite Grassland (Gm 26)
Woodbush Granite Grassland (Gm 25)
Xhariep Karroid Grassland (Gh 3)
Zastron Moist Grassland (Gm 1)
Fynbos
81 Fynbos vegetation types, code FF:
Agulhas Limestone Fynbos (FFl 1)
Agulhas Sand Fynbos (FFd 7)
Albertinia Sand Fynbos (FFd 9)
Algoa Sandstone Fynbos (FFs 29)
Atlantis Sand Fynbos (FFd 4)
Bokkeveld Sandstone Fynbos (FFs 1)
Boland Granite Fynbos (FFg 2)
Breede Alluvium Fynbos (FFa 2)
Breede Quartzite Fynbos (FFq 4)
Breede Sand Fynbos (FFd 8)
Breede Shale Fynbos (FFh 4)
Canca Limestone Fynbos (FFl 3)
Cape Flats Sand Fynbos (FFd 5)
Cape Winelands Shale Fynbos (FFh 5)
Cederberg Sandstone Fynbos (FFs 4)
Central Coastal Shale Band Vegetation (FFb 4)
Central Inland Shale Band Vegetation (FFb 3)
De Hoop Limestone Fynbos (FFl 2)
Eastern Coastal Shale Band Vegetation (FFb 6)
Eastern Inland Shale Band Vegetation (FFb 5)
Elgin Shale Fynbos (FFh 6)
Elim Ferricrete Fynbos (FFf 1)
Garden Route Granite Fynbos (FFg 5)
Garden Route Shale Fynbos (FFh 9)
Graafwater Sandstone Fynbos (FFs 2)
Greyton Shale Fynbos (FFh 7)
Grootrivier Quartzite Fynbos (FFq 5)
Hangklip Sand Fynbos (FFd 6)
Hawequas Sandstone Fynbos (FFs 10)
Hopefield Sand Fynbos (FFd 3)
Kamiesberg Granite Fynbos (FFg 1)
Kango Conglomerate Fynbos (FFt 1)
Knysna Sand Fynbos (FFd 10)
Kogelberg Sandstone Fynbos (FFs 11)
Kouebokkeveld Alluvium Fynbos (FFa 1)
Kouebokkeveld Shale Fynbos (FFh 1)
Kouga Grassy Sandstone Fynbos (FFs 28)
Kouga Sandstone Fynbos (FFs 27)
Leipoldtville Sand Fynbos (FFd 2)
Loerie Conglomerate Fynbos (FFt 2)
Lourensford Alluvium Fynbos (FFa 4)
Matjiesfontein Quartzite Fynbos (FFq 3)
Matjiesfontein Shale Fynbos (FFh 2)
Montagu Shale Fynbos (FFh 8)
Namaqualand Sand Fynbos (FFd 1)
North Hex Sandstone Fynbos (FFs 7)
North Kammanassie Sandstone Fynbos (FFs 25)
North Langeberg Sandstone Fynbos (FFs 15)
North Outeniqua Sandstone Fynbos (FFs 18)
North Rooiberg Sandstone Fynbos (FFs 21)
North Sonderend Sandstone Fynbos (FFs 13)?
North Swartberg Sandstone Fynbos (FFs 23)
Northern Inland Shale Band Vegetation (FFb 1)
Olifants Sandstone Fynbos (FFs 3)
Overberg Sandstone Fynbos (FFs 12)
Peninsula Granite Fynbos (FFg 3)
Peninsula Sandstone Fynbos (FFs 9)
Piketberg Sandstone Fynbos (FFs 6)
Potberg Ferricrete Fynbos (FFf 2)
Potberg Sandstone Fynbos (FFs 17)
Robertson Granite Fynbos (FFg 4)
South Hex Sandstone Fynbos (FFs 8)
South Kammanassie Sandstone Fynbos (FFs 26)
South Langeberg Sandstone Fynbos (FFs 16)
South Outeniqua Sandstone Fynbos (FFs 19)
South Rooiberg Sandstone Fynbos (FFs 22)
South Sonderend Sandstone Fynbos (FFs 14)
South Swartberg Sandstone Fynbos (FFs 24)
Southern Cape Dune Fynbos (FFd 11)
Stinkfonteinberge Quartzite Fynbos (FFq 1)
Suurberg Quartzite Fynbos (FFq 6)
Suurberg Shale Fynbos (FFh 10)
Swartberg Altimontane Sandstone Fynbos (FFs 31)
Swartberg Shale Fynbos (FFh 3)
Swartland Alluvium Fynbos (FFa 3)
Swartruggens Quartzite Fynbos (FFq 2)
Swellendam Silcrete Fynbos (FFc 1)
Tsitsikamma Sandstone Fynbos (FFs 20)
Western Altimontane Sandstone Fynbos (FFs 30)
Western Coastal Shale Band Vegetation (FFb 2)
Winterhoek Sandstone Fynbos (FFs 5)
Renosterveld
29 Renosterveld vegetation types, code FR:
Baviaanskloof Shale Renosterveld (FRs 18)
Breede Alluvium Renosterveld (FRa 1)
Breede Shale Renosterveld (FRs 8)
Central Mountain Shale Renosterveld (FRs 5)
Central Ruêns Shale Renosterveld (FRs 12)
Ceres Shale Renosterveld (FRs 4)
Eastern Ruêns Shale Renosterveld (FRs 13)
Hantam Plateau Dolerite Renosterveld (FRd 2)
Humansdorp Shale Renosterveld (FRs 19)
Kango Limestone Renosterveld (FRl 1)
Langkloof Shale Renosterveld (FRs 17)
Matjiesfontein Shale Renosterveld (FRs 6)
Montagu Shale Renosterveld (FRs 7)
Mossel Bay Shale Renosterveld (FRs 14)
Namaqualand Granite Renosterveld (FRg 1)
Nieuwoudtville Shale Renosterveld (FRs 2)
Nieuwoudtville-Roggeveld Dolerite Renosterveld (FRd 1)
Peninsula Shale Renosterveld (FRs 10)
Robertson Granite Renosterveld (FRg 3)
Roggeveld Shale Renosterveld (FRs 3)
Ruêns Silcrete Renosterveld (FRc 2)
Swartberg Shale Renosterveld (FRs 15)
Swartland Alluvium Renosterveld (FRa 2)
Swartland Granite Renosterveld (FRg 2)
Swartland Shale Renosterveld (FRs 9)
Swartland Silcrete Renosterveld (FRc 1)
Uniondale Shale Renosterveld (FRs 16)
Vanrhynsdorp Shale Renosterveld (FRs 1)
Western Ruêns Shale Renosterveld (FRs 11)
Succulent Karoo
65 Succulent Karoo vegetation types, code SK:
Aggeneys Gravel Vygieveld (SKr 19)
Agter-Sederberg Shrubland (SKv 3)
Anenous Plateau Shrubland (SKr 15)
Bushmanland Inselberg Shrubland (SKr 18)
Central Knersvlakte Vygieveld (SKk 2)
Central Richtersveld Mountain Shrubland (SKr 1)
Citrusdal Vygieveld (SKk 7)
Die Plate Succulent Shrubland (SKr 10)
Doringrivier Quartzite Karoo (SKv 1)
Eastern Little Karoo (SKv 11)
Eenriet Plains Succulent Shrubland (SKr 17)
Goariep Mountain Succulent Shrubland (SKr 3)
Hantam Karoo (SKt 2)
Kamiesberg Mountains Shrubland (SKn 6)
Klawer Sandy Shrubland (SKs 13)
Knersvlakte Dolomite Vygieveld (SKk 6)
Knersvlakte Quartz Vygieveld (SKk 3)
Knersvlakte Shale Vygieveld (SKk 4)
Koedoesberge-Moordenaars Karoo (SKv 6)
Kosiesberg Succulent Shrubland (SKr 12)
Lekkersing Succulent Shrubland (SKr 4)
Little Karoo Quartz Vygieveld (SKv 10)
Namaqualand Arid Grassland (SKs 11)
Namaqualand Blomveld (SKn 3)
Namaqualand Coastal Duneveld (SKs 8)
Namaqualand Heuweltjie Strandveld (SKs 14)
Namaqualand Heuweltjieveld (SKn 4)
Namaqualand Inland Duneveld (SKs 9)
Namaqualand Klipkoppe Shrubland (SKn 1)
Namaqualand Shale Shrubland (SKn 2)
Namaqualand Spinescent Grassland (SKs 12)
Namaqualand Strandveld (SKs 7)
Northern Knersvlakte Vygieveld (SKk 1)
Northern Richtersveld Scorpionstailveld (SKr 7)
Northern Richtersveld Yellow Duneveld (SKs 2)
Oograbies Plains Sandy Grassland (SKs 6)
Piketberg Quartz Succulent Shrubland (SKk 8)
Platbakkies Succulent Shrubland (SKn 5)
Prince Albert Succulent Karoo (SKv 13)
Richtersveld Coastal Duneveld (SKs 1)
Richtersveld Red Duneveld (SKs 5)
Richtersveld Sandy Coastal Scorpionstailveld (SKs 4)
Riethuis-Wallekraal Quartz Vygieveld (SKs 10)
Robertson Karoo (SKv 7)
Roggeveld Karoo (SKt 3)
Rooiberg Quartz Vygieveld (SKr 11)
Rosyntjieberg Succulent Shrubland (SKr 8)
Southern Namaqualand Quartzite Klipkoppe Shrubland (SKk 10)
Southern Richtersveld Inselberg Shrubland (SKr 14)
Southern Richtersveld Scorpionstailveld (SKr 13)
Southern Richtersveld Yellow Duneveld (SKs 3)
Steytlerville Karoo (SKv 14)
Stinkfonteinberge Eastern Apron Shrubland (SKr 6)
Swartruggens Quartzite Karoo (SKv 2)
Tanqua Escarpment Shrubland (SKv 4)
Tanqua Karoo (SKv 5)
Tatasberg Mountain Succulent Shrubland (SKr 9)
Umdaus Mountains Succulent Shrubland (SKr 16)
Upper Annisvlakte Succulent Shrubland (SKr 2)
Vanrhynsdorp Gannabosveld (SKk 5)
Vyftienmyl se Berge Succulent Shrubland (SKr 5)
Western Bushmanland Klipveld (SKt 1)
Western Gwarrieveld (SKv 9)
Western Little Karoo (SKv 8)
Willowmore Gwarrieveld (SKv 12)
Albany Thickets and Strandveld
54 Albany thickets and Strandveld vegetation types, codes AT and FS:
Albany Arid Thicket (AT 15) – Also known as Albany Spekboomveld, and shown on the 2012 VEGMAP as AT8 Kowie Thicket. Albany Arid Thicket occurs in the Eastern Cape Province. The type location is a steep, arid, north facing slope north of Grahamstown. It is a low thicket vegetation type of about 2m height dominated by succulent shrubs and woody karroid shrubs with occasional trees and emergent succulent trees. The soils are mainly argillaceous (clay) of the Ecca and Dwyka groups, at altitudes from 254 to 521m above sea level. Land type is Fb, mainly tillites. Rainfall is non-seasonal, typically from 475 to 521mm per year, with occasional frost higher up the slopes, and snow may fall in winter. Mean monthly maximum temperature is 27°C in February and mean monthly minimum 6°C in July. Albany Arid Thicket is the most species rich South African arid thicket type. Characteristic species include: Aloe ferox, Aloe speciosa (endemic), Boscia oleoides(endemic), Commiphora harveyi, Crassula ovata(endemic), Digitaria eriantha, Encephalartos trispinosus (endemic), Euclea undulata, Euphorbia bothae (endemic), Euphorbia tetragona (endemic), Pappea capensis, Portulacaria afra, Ptaeroxylon obliquum, Rhigozum obovatum, Strelitzia reginae. There is no data on threat level and the vegetation type is poorly protected.
Albany Bontveld (AT 16) — A vegetation type from the Eastern Cape Province, on flat-topped hills between the southern end of the Ecca Pass and Table Hill, to the north and northeast of Grahamstown.
Albany Mesic Thicket (AT 17)
Albany Valley Thicket (AT 18)
Baviaans Valley Thicket (AT 19)
Bethelsdorp Bontveld (AT 20)
Blombos Strandveld (FS 8)
Buffels Mesic Thicket (AT 21)
Buffels Valley Thicket (AT 22)
Cape Flats Dune Strandveld (FS 6)
Crossroads Grassland Thicket (AT 23)
Doubledrift Karroid Thicket (AT 24)
Eastern Gwarrieveld (AT 25)
Elands Forest Thicket (AT 26)
Escarpment Arid Thicket (AT 27)
Escarpment Mesic Thicket (AT 28)
Escarpment Valley Thicket (AT 29)
Fish Arid Thicket (AT 30)
Fish Mesic Thicket (AT 31)
Fish Valley Thicket (AT 32)
Gamka Arid Thicket (AT 33)
Gamka Valley Thicket (AT 34)
Geluk Grassland Thicket (AT 35)
Goukamma Dune Thicket (AT 36)
Gouritz Valley Thicket (AT 37)
Grahamstown Grassland Thicket (AT 38)
Grassridge Bontveld (AT 39)
Groot Brak Dune Strandveld (FS 9)
Hamburg Dune Thicket (AT 56)
Hartenbos Dune Thicket (AT 40)
Kasouga Dune Thicket (AT 41)
Koedoeskloof Karroid Thicket (AT 42)
Lambert's Bay Strandveld (FS 1)
Langebaan Dune Strandveld (FS 5)
Mons Ruber Fynbos Thicket (AT 43)
Motherwell Karroid Thicket (AT 44)
Nanaga Savanna Thicket (AT 45)
Oudshoorn Karroid Thicket (AT 46)
Overberg Dune Strandveld (FS 7)
Saldanha Flats Strandveld (FS 3)
Saldanha Granite Strandveld (FS 2)
Saldanha Limestone Strandveld (FS 4)
Saltaire Karroid Thicket (AT 47)
Sardinia Forest Thicket (AT 48)
St Francis Dune Thicket (AT 57)
Subtropical Dune Thicket (AZs 3)
Sundays Arid Thicket (AT 49)
Sundays Mesic Thicket (AT 50)
Sundays Valley Thicket (AT 51)
Thorndale Forest Thicket (AT 52)
Umtiza Forest Thicket (AT 53)
Vanstadens Forest Thicket (AT 54)
Western Gwarrieveld (AT 55)
Willowmore Gwarrieveld (AT 58)
Nama Karoo
29 Nama Karoo and desert vegetation types, codes NK and D:
Albany Broken Veld (NKl 4)
Blouputs Karroid Thornveld (NKb 2)
Bushmanland Arid Grassland (NKb 3)
Bushmanland Basin Shrubland (NKb 6)
Bushmanland Sandy Grassland (NKb 4)
Eastern Lower Karoo (NKl 2)
Eastern Upper Karoo (NKu 4)
Gamka Karoo (NKl 1)
Kalahari Karroid Shrubland (NKb 5)
Lower Gariep Broken Veld (NKb 1)
Lower Karoo Gwarrieveld (NKl 3)
Northern Upper Karoo (NKu 3)
Upper Karoo Hardeveld (NKu 2)
Western Upper Karoo (NKu 1)
Alexander Bay Coastal Duneveld (Dn 1)
Eastern Gariep Plains Desert (Dg 9)
Eastern Gariep Rocky Desert (Dg 10)
Helskloof Canyon Desert (Dg 6)
Kahams Mountain Desert (Dg 5)
Kwaggarug Mountain Desert (Dg 4)
Namib Lichen Fields (Dn 2)
Noms Mountain Desert (Dg 1)
Northern Nababiepsberge Mountain Desert (Dg 7)
Richtersberg Mountain Desert (Dg 2)
Richtersveld Sheet Wash Desert (Dg 3)
Southern Nababiepsberge Mountain Desert (Dg 8)
Western Gariep Hills Desert (Dn 5)
Western Gariep Lowland Desert (Dn 4)
Western Gariep Plains Desert (Dn 3)
Azonal
35 Azonal vegetation types, code AZ:
Albany Alluvial Vegetation (AZa 6)
Albany Dune Strandveld (AZs 2)
Algoa Dune Strandveld (AZs 1)
Arid Estuarine Salt Marshes (AZe 1)
Bushmanland Vloere (AZi 5)
Cape Estuarine Salt Marshes (AZe 2)
Cape Inland Salt Pans (AZi 9)
Cape Lowland Alluvial Vegetation (AZa 2)
Cape Lowland Freshwater Wetlands (AZf 1)
Cape Seashore Vegetation (AZd 3)
Cape Vernal Pools (AZf 2)
Drakensberg Wetlands (AZf 4)
Eastern Temperate Freshwater Wetlands (AZf 3)
Fynbos Riparian Vegetation (AZa 1)
Highveld Alluvial Vegetation (AZa 5)
Highveld Salt Pans (AZi 10)
Lesotho Mires (AZf 5)
Lower Gariep Alluvial Vegetation (AZa 3)
Muscadel Riviere (AZi 8)
Namaqualand Riviere (AZi 1)
Namaqualand Salt Pans (AZi 2)
Namaqualand Seashore Vegetation (AZd 2)
Namib Seashore Vegetation (AZd 1)
Southern Kalahari Mekgacha (AZi 3)
Southern Kalahari Salt Pans (AZi 4)
Southern Karoo Riviere (AZi 6)
Subantarctic Kelp Bed Vegetation (Azm 2)
Subtropical Alluvial Vegetation (AZa 7)
Subtropical Dune Thicket (AZs 3)
Subtropical Estuarine Salt Marshes (AZe 3)
Subtropical Freshwater Wetlands (AZf 6)
Subtropical Salt Pans (AZi 11)
Subtropical Seashore Vegetation (AZd 4)
Tanqua Wash Riviere (AZi 7)
Upper Gariep Alluvial Vegetation (AZa 4)
Forest
17 Forest and coastal belt vegetation types, codes FO and CB
KwaZulu-Natal Coastal Belt (CB 3)
Maputaland Coastal Belt (CB 1)
Maputaland Wooded Grassland (CB 2)
Pondoland-Natal Sandstone Coastal Sourveld (CB 4)
Transkei Coastal Belt (CB 5)
Ironwood Dry Forest (FOz 9)
Lowveld Riverine Forest (FOa 1)
Mangrove Forest (FOa 3)
Northern Afrotemperate Forest (FOz 2)
Northern Coastal Forest (FOz 7)
Northern Mistbelt Forest (FOz 4)
Sand Forest (FOz 8)
Scarp Forest (FOz 5)
Southern Afrotemperate Forest (FOz 1)
Southern Coastal Forest (FOz 6)
Southern Mistbelt Forest (FOz 3)
Swamp Forest (FOa 2)
Indian Ocean Coastal Belt
KwaZulu-Natal Coastal Belt Grassland
KwaZulu-Natal Coastal Belt Thornveld
Maputaland Coastal Belt (CB 1)
Maputaland Wooded Grassland (CB 2)
Pondoland-Ugu Sandstone Coastal Sourveld (CB 4)
Transkei Coastal Belt (CB 5)
Desert
Alexander Bay Coastal Duneveld
Eastern Gariep Plains Desert
Eastern Gariep Rocky Desert
Kahams Mountain Desert
Kwaggarug Mountain Desert
Namib Lichen Fields
Noms Mountain Desert
Northern Nababiepsberge Mountain Desert
Richtersberg Mountain Desert
Richtersveld Sheet Wash Desert
Southern Nababiepsberge Mountain Desert
Western Gariep Hills Desert
Western Gariep Lowland Desert
Western Gariep Plains Desert
Subantarctic
8 Subantarctic vegetation types, code ST:
Subantarctic Biotic Herbfield and Grassland (ST 2)
Subantarctic Cinder Cone Vegetation (ST 7)
Subantarctic Coastal Vegetation (ST 1)
Subantarctic Drainage Line Vegetation (ST 4)
Subantarctic Fellfield (ST 6)
Subantarctic Fernbrake Vegetation (ST 5)
Subantarctic Mire (ST 3)
Subantarctic Polar Desert (PD 1)
References
Biodiversity of South Africa
Ecology | List of vegetation types of South Africa | [
"Biology"
] | 6,540 | [
"Ecology",
"Biodiversity",
"Biodiversity of South Africa"
] |
65,873,745 | https://en.wikipedia.org/wiki/DIORIT | Diorit was an experimental nuclear research reactor at the Swiss Federal Institute for Reactor Research (EIR) in Würenlingen (Canton of Aargau, Switzerland)
This nuclear reactor was operated by EIR from 1960 to 1977. Heavy water (D2O) was used as the moderator, as well as the coolant. The initially commissioned reactor had a thermal power of 20 MW. Natural uranium was initially used as fuel, which was later changed to enriched uranium. The long, aluminium and nickel cased fuel rods were produced by AMF Atomics Canada Ltd.
Military background
Heavy water (deuterium) has a particularly good neutron economy, which in turn makes for good production of high-quality weapons-grade plutonium. However, Diorit was only ever used for civil research purposes and weapons-grade plutonium was never extracted from it. This didn't stop the Swiss Army from thinking of itself as an emerging nuclear power during the Cold War, as historian Jürg Stüssi-Lauterburg found in a study about previously-classified meeting notes. The army's aspirations for nuclear armament during some phases of the Cold War were at least somewhat public. For example, a major from Solothurn wrote the following in an anniversary publication, in 1957: "... military considerations therefore compel the procurement of nuclear weapons, even for a state whose army limits itself to defence only."
1967 incident
In 1967 the reactor produced a partially melted fuel rod, which contaminated the reactor hall. Considerably raised levels of radioactivity were also measured in the River Aare. Subsequently, the complete primary heavy water cooling system had to be decontaminated by chemical milling.
Conversion to Diorit II
Following the Incident of 1967, the decision was made to swap out the reactor vessel. The conversion also served to transition from natural uranium fuel to enriched uranium oxide. Some workers were exposed to raised radiation levels during construction. Single doses were up to 1020 mrem, while the highest accumulated dose was 2600 mrem (26 mSv).
Decommissioning
Operation of Diorit ceased in 1977. First plans for dismantling were made in the early 80s, while the actual decision was made in 1994. During decommissioning of the reactor the following amounts of radioactive waste accrued: 250 t steel, 120 t concrete, 5.4 t aluminium and alloys, as well as 45 t graphite.
The burnt out fuel rods were stored in a CASTOR 1c Diorit dry cask storage container until they were transported to the central interim storage site (ZZL) of Zwilag.
See also
Nuclear power in Switzerland
List of civilian nuclear accidents
References
Former nuclear research institutes
Nuclear accidents and incidents
Radioactively contaminated areas
1957 establishments in Switzerland
1977 disestablishments in Switzerland
Former nuclear power stations in Switzerland | DIORIT | [
"Chemistry",
"Technology"
] | 579 | [
"Radioactively contaminated areas",
"Radioactive contamination",
"Nuclear accidents and incidents",
"Soil contamination",
"Radioactivity"
] |
65,875,220 | https://en.wikipedia.org/wiki/Claviceps%20pusilla | Claviceps pusilla, also known as bluestem ergot, is a parasitic fungus primarily of the grass tribe Angropogoneae, particularly those in the tribe referred to as "bluestem". C. pusilla occasionally manifests characteristic triangular conidia which appear to be unique among Claviceps species.
Range
Claviceps pusilla has been documented in Australia, and in the US in the states of Texas, New Mexico, Oklahoma, and Iowa.
The earliest record found for C. pusilla was by Pammel and Weems in 1900. Scientists have identified C. pusilla on Andropogon species based on examination of ascomata from germinated sclerotia. Examination of a collection from Texas revealed yellow capitula characteristic of C. pusilla. However, in certain collections labeled as C. pusilla, triangular conidia characteristic of this species were not present. Additional collections need to be examined to confirm the presence of C. pusilla in the United States. C. pusilla has a wide geographical distribution, is known from Andropogon spp., and likely occurs on Andropogon spp. in the United States. However, we consider reports of C. purpurea var. purpurea on Andropogon spp. to be incorrect.
Ecology
Claviceps pusilla infects the inflorescence of certain grasses by replacing caryopses with fungal sclerotia.
List of published host species:
Andropogon gerardii Vitman = Andropogon furcatus Muhl. in Wild.
Andropogon hallii Hack.
Andropogon spp.
Arundinella nepalensis
Bothriochloa biloba
Bothriochloa bladhii
Bothriochloa decipiens
Bothriochloa erianthoides
Bothriochloa ewartiana
Bothriochloa glabra
Bothriochloa insculpta
Bothriochloa ischaemum (L.) Keng = Andropogon ischaemum L.
Bothriochloa macra
Bothriochloa pertusa
Capillipedium spicigerum
Chrysopogon filipes
Cymbopogon refractus
Dichanthium annulatum
Dichanthium aristatum
Dichanthium caricosum
Dichanthium sericeum
Heteropogon contortus
Hyparrhenia hirta
Pennisetum glaucum
Sarga leiocladum
Sarga plumosum
Schizachyrium scoparium (Michx.) Nash = Andropogon scoparius Michx.
Themeda triandra
Urochloa sp.
Taxonomy
A synonym for Claviceps pusilla Ces. is Hypocrea pusilla Ces..
References
Clavicipitaceae
Fungus species | Claviceps pusilla | [
"Biology"
] | 612 | [
"Fungi",
"Fungus species"
] |
65,876,511 | https://en.wikipedia.org/wiki/Seed%20blanking | Seed blanking is a plant disease injury causing the seed producing anatomy to contain no seeds despite otherwise normal development. This term is used to contrast with other causes of seed production failure, including but not limited to earlier or more widespread damage to the plant. For one example, wheat blast causes widespread seed blanking.
References
Plant diseases
Seeds
Plants | Seed blanking | [
"Biology"
] | 69 | [
"Plants"
] |
65,876,566 | https://en.wikipedia.org/wiki/Tongan%20tropical%20moist%20forests | The Tongan tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion that includes the Tonga archipelago and Niue.
Geography
The ecoregion includes the Tonga archipelago, a group of 170 islands that extends 800 km north to south between 15º to 23ºS latitude and 173º to 177º W longitude, and comprise the nation of Tonga. It also includes Niue, which lies 400 km east of Tonga at 19º S latitude and 169º W longitude.
The Tonga archipelago lies at the boundary of the Pacific and the Australian tectonic plates, and the islands were created by the subduction of the Pacific Plate under the Australian Plate. The islands on the eastern side of the chain are mostly made up of uplifted coraline rocks lying atop blocks of oceanic or continental crust. Some of the larger eastern islands are Foa, Lifuka, Vavaʻu, 'Eua, and Tongatapu. Several of the islands on the western side of the chain are of stratovolcanos, including 'Ata, Tofua, Kao, Late, and Fonualei in the south, and Niuafo'ou, Niuatoputapu, and Tafahi in the north. The highest peak in the islands is 1,030 metres on Kao. Many islands have fringing coral reefs, and others have become coral atolls as the central islands eroded away or subsided.
Niue is an uplifted coral atoll, with cliffs along the shoreline and without a fringing coral reef. It covers an area of 259 km2.
The islands have been inhabited for about 3000 years.
Climate
The ecoregion has a humid tropical climate. Mean daily temperatures generally range from 24º to 30 °C in February, the warmest month, to 20º to 26 °C in August, the coolest month. Average annual rainfall is 2000 mm or more, and higher on windward slopes and at higher elevations. Rainfall is generally higher between December and April. Leeward lowlands can experience seasonal droughts between May and November.
Flora
The natural vegetation is moist broadleaf forest.
Tropical lowland rain forests predominate below 500 meters elevation. Evergreen trees form a continuous canopy up to 30 meters in height. Common canopy trees include Diospyros spp., Rhus taitensis, Alphitonia zizyphoides, Calophyllum neo-ebudicum, Cryptocarya turbinata, Elattostachys apetala, Litsea mellifera, Maniltoa grandiflora, Myristica hypargyraea, Zanthoxylum pinnatum, Garcinia myrtifolia, Neonauclea forsteri, Didymocheton tongensis (on 'Eua), Podocarpus pallidus, Inocarpus fagifer, Erythrina fusca, Pisonia grandis, Pittosporum arborescens, Garuga floribunda, Ficus obliqua, Pleiogynium timoriense, and Cynometra grandiflora. The understorey includes dense clumps of the fern Dicranopteris linearis and the shrubs Piper puberulum and Psychotria insularum.
On coastal dunes and relatively recent lava and ash deposits where soils are thinner and drier, forests of Casuarina equisetifolia predominate, with low trees and shrubs including Pandanus tectorius, Syzygium dealbatum, Hibiscus tiliaceus, and Scaevola taccada.
Littoral forests of Hernandia nymphaeifolia, Barringtonia asiatica, and Casuarina equisetifolia grow closest to the coast in areas with salt spray. Immediately inland are coastal forests with Pisonia grandis and Excoecaria agallocha as the predominant trees.
Mangrove scrub and mangrove forest are found in saltwater wetlands on coral atolls and around the shores of the larger islands' coastal lagoons. Mangrove scrub is found on estuaries and reef flats and on the edges of mangrove forests. The small- to medium-sized trees Rhizophora mangle, Rhizophora stylosa, and Lumnitzera littorea are dominant. Where conditions are favorable mangrove forests dominated by Bruguiera gymnorhiza with Xylocarpus moluccensis and X. granatum replace the mangrove scrub.
Montane forests are found above 500 metres elevation on the island of Tafahi. The climate is cooler and more humid than that of the lowland forests. Characteristic montane forest tree species include Syzygium spp., Fagraea berteroana, Bischofia javanica, Hernandia moerenhoutiana, Astronidium spp., and Reynoldsia spp. Other montane plant communities are upland volcanic scrub on Kao's young volcanic slopes, and fernlands dominated by Dicranopteris linearis with Lycopodium cernuum and Miscanthus floridulus in highland areas of 'Eua disturbed by human-caused fires.
There are 419 native species of vascular plants in the Tonga, and approximately 3% are endemic.
Plants endemic to Tonga include Alphitonia franguloides var. obtusa, Arytera bifoliata, Grewia amicorum, Grewia populoides, Guioa lentiscifolia, Meiogyne amicorum, Oldenlandia debilis, Pandanus amicalis, Pandanus tongatapuensis, Pandanus vavauensis, Phyllanthus amicorum, Pittosporum yunckeri, Psychotria euaensis, Scaevola porrecta, and Xylosma smithiana.
Several species are endemic to one or two islands:
Phyllostegia tongaensis is endemic to 'Ata
Aglaia heterotricha, Didymocheton tongensis, Hedycarya alternifolia, Ixora yunckeri, Plantago euana, and the fern Thelypteris macroptera are endemic to 'Eua
Dennstaedtia parksii and the orchid Robiquetia tongaensis are endemic to 'Eua and Tongatapu
the conifer Podocarpus pallidus is endemic to 'Eua and Vava'u
Psychotria kaoensis and Selaginella yunckeri are endemic to Kao
Atractocarpus crosbyi, Casearia buelowii, and the palm Pritchardia pacifica are endemic to Vava'u.
Peperomia pallida var. niueana, Myoporum nieuanum, and the orchid Dendrobium niueense are endemic to Niue.
Fauna
There are no native land mammals in the ecoregion. Native bats include the Pacific flying fox (Pteropus tonganus) and Pacific sheath-tailed bat (Emballonura semicaudata). The black rat (Rattus rattus) and brown rat (R. norvegicus) were introduced to the islands by humans, and have decimated the island's birds.
Tonga has native 20 species of land and freshwater birds. The Tongan whistler (Pachycephala jacquinoti) is an endemic species found the Vava'u Group. The Niuafo'ou megapode (Megapodius pritchardii) is endemic to Niuafo'ou island. Other native birds include the red shining parrot (Prosopeia tabuensis) and blue-crowned lorikeet (Vini australis).
The islands are home to numerous seabirds, including brown noddy (Anous stolidus), Phoenix petrel (Pterodroma alba), and bristle-thighed curlew (Numenius tahitiensis). Seabird breeding colonies are mostly limited to offshore islets free of rats, which prey on eggs and chicks.
Niue has 12 native species of land birds and six species of seabirds, including two endemic subspecies.
There are 20 known species of reptiles in the ecoregion. They include the Lau banded iguana (Brachylophus fasciatus), the boa Candoia bibroni, nine species of gecko, and nine species of skink. The skink Tachygia microlepsis is now considered extinct. Fossil remains of a giant land iguana have been found, which became extinct after the first humans arrived.
Protected areas
A 2017 assessment found that 117 km2, or 21%, of the ecoregion is in protected areas.
References
Oceanian ecoregions
Tropical and subtropical moist broadleaf forests
Biota of Tonga
Geography of Tonga
Environment of Tonga
Geography of Niue
Environment of Niue
Ecoregions of Tonga
Ecoregions of Niue | Tongan tropical moist forests | [
"Biology"
] | 1,827 | [
"Biota by country",
"Biota of Tonga"
] |
65,877,174 | https://en.wikipedia.org/wiki/Corporate%20sociopolitical%20activism | Corporate sociopolitical activism (CSA) refers to a firm's public demonstration of support or opposition to a partisan sociopolitical issue. CSA has become increasingly prominent in the 2010s and 2020s, as firms have taken stances on issues such as climate change, racial justice, reproductive rights, gun control, immigration, LGBTQ+ rights, and gender equality.
Several terms, such as woke capitalism, woke capital, and stakeholder capitalism, are used by some commentators to refer to a form of marketing, advertising, and corporate structures that pertains to sociopolitical standpoints tied to social justice and activist causes. The term was coined by columnist Ross Douthat in "The Rise of Woke Capital", an article written for and published in The New York Times in 2018.
CSA is comparable but distinct from two related firm activities: corporate social responsibility (CSR) and corporate political activity (CPA). Firms may engage in CSA to appeal to purpose-driven ideals, as well as contribute to more strategic motives, in line with consumers' existing preferences for moral purchasing options. A recent study found that 64% of global consumers choose to buy or boycott a given brand on the basis of its political leanings, a result suggesting the increasing importance of ethical consumerism practices.
A 2020 survey of CMOs revealed that a growing proportion of marketing leaders find it acceptable to make changes to products and services in response to political issues (47%), have executives speak out on political issues (33%), and use marketing communications to speak out on political issues (28%). Furthermore, brands engaged in an unprecedented level of activist behavior in response to consumers protesting racial injustice in 2020.
Firms have historically strayed from vocalizing stances on controversial sociopolitical matters, with the understanding that doing so could sever certain stakeholder relationships; however, modern cultural shifts have precipitated a "hyper-partisan" climate, leading to demand for firms to exercise purpose-driven efforts in the marketplace. As stated by Richard Edelman, chief executive officer (CEO) of Edelman, "Brands are now being pushed to go beyond their classic business interests to become advocates. It is a new relationship between a company and consumer, where a purchase is premised on the brand’s willingness to live its values, act with purpose, and, if necessary, make the leap into activism."
Definition
CSA is a unique form of cause-related firm behavior defined broadly by two distinct characteristics: publicity and partisanship. Specifically, CSA involves a firm's public support of or opposition to a partisan sociopolitical issue. Such issues are described as "salient unresolved social matters on which societal and institutional opinion is split, thus potentially engendering acrimonious debate among groups". Notably, while the controversy surrounding a given issue can change or be resolved, a firm's efforts may be considered CSA to the extent that they reflect engagement with an issue defined as partisan at a given point in time, politics, and culture. Furthermore, the term "brand activism" has been used to describe similar efforts by individual brands (i.e. owned by firms) to vocalize public stances on sociopolitical issues; brand activism can, thus, be considered CSA delivered through a brand's voice.
Conceptual distinctions
Corporate social responsibility
CSR involves firms' contributions to widely favored societal goals (e.g. community resources, education, and donations to disease prevention research) via philanthropic or charitable efforts, CSA pertains to a firm's engagement in causes for which there is no universally acceptable correct response. Furthermore, CSA may involve a lower level of monetary investment (e.g. a press release or an open letter) compared to CSR; however, there is greater risk associated with CSA, due in part to the potential for backlash from various stakeholders.
Corporate political activity
CSA is distinct from CPA—a firm's efforts (e.g. campaign contributions, lobbying, and donations to political action committees) to sway political processes and gain policy-related market advantages. While both types of firm activities reflect involvement in the political process, they differ in the extent to which they are publicized. CSA is often utilized as a public demonstration of a firm's core values and principles. Conversely, CPA is an often-discreet activity that is typically made public only through "accidental disclosure".
Examples
Firms have increasingly taken activist stances on sociopolitical issues across a variety of domains.
Racial justice
Firms have spoken out about racial justice in a number of ways (e.g. affirming support for the Black Lives Matter movement, donating a portion of profits to civil rights organizations). Among the most prominent examples of racial justice CSA came in September 2018 when Nike announced football player Colin Kaepernick as the spokesperson for its thirtieth anniversary advertisement campaign. Notably, Kaepernick stirred national debate in 2016 by kneeling during the National Anthem in protest of racial inequality and police brutality in the United States. In Nike's campaign, Kaepernick said, "Believe in something, even if it means sacrificing everything." News agencies characterized this tagline as implicit support for Kaepernick's platform of racial justice advocacy.
While Nike's decision initially sparked consumer backlash, as well as a dip in stock price, the firm's value reached an all-time high only a week later. According to a Quinnipiac University poll, much of the persistent consumer support for the ad came from consumers between 18 and 34, two-thirds of whom approved of Nike's actions. This case has been considered a critical turning point in the emergence of CSA as a prominent brand practice. Additional examples of racial justice CSA include the following:
Home Depot CEO Craig Meaner said in a statement, "We are all confronting deep pain and anguish over the senseless killing of George Floyd, Ahmaud Arbery, and other unarmed Black men and women in our country. We cannot ignore that their deaths are part of a pattern of racism and reflect the harsh reality that as a nation we are much too far from fulfilling the promise of equal justice for all."
Netflix promoted a new Black Lives Matter collection to U.S. subscribers, featuring a number of television and movie titles about racial injustice and the experience of Black Americans.
Walmart announced that it will donate $100 million over five years to create a new center for racial equity.
LGBTQ+ rights
Firms have utilized both internal and external resources to take a stand on issues facing the LGBTQ+ community. For instance, many firms act as corporate sponsors of Pride parades internationally and assist in LGBTQ+ community-building efforts. Published since 2002, the Human Rights Campaign has utilized its Corporate Equality Index (CEI) to measure the extent to which American businesses treat equitably their LGBTQ+ employees, customers, and investors. Criteria used to assess companies include, among others, a written policy of non-discrimination based on sexual orientation, gender identity, and gender expression; appropriate and respectful advertising to the LGBTQ+ community; and transgender-inclusive health benefits.
There has been an increase in the number of firms with a perfect CEI rating every year since the tool's inception. Such firms frequently release statements and press releases to express satisfaction at having been recognized for their diversity and inclusivity efforts. Notably, many brands have also released Pride-related merchandise in recent years to signal support for LGBTQ+ rights, as well as position themselves as advocates for LGBTQ+ consumers.
Converse released a collection of Pride-inspired low- and high-top sneakers featuring a rainbow flag with a brown and black stripe dedicated to queer people of color. Also included in this collection was a pair of sneakers adorned with the pink, light blue, and white colors of the transgender flag.
Sephora's "We Love Pride" make-up collection featured a metallic red lipstick called "Love Is Love". The brand donated a portion of sales to a variety of LGBTQ+ charities.
Fossil released its second annual Pride Watch, featuring a bezel with all the colors of the rainbow flag. U.S. sales benefitted the Hetrick-Martin Institute, the nation's oldest and largest LGBTQ+ youth organization.
Climate change
While sustainable business practices have long been a component of firms' CSR activities, some companies have taken an activist stance in recent years to address climate change more explicitly. For example, the brand Patagonia has established itself as a chief market-based environmental justice advocate. Its November 2011 "Don't Buy This Jacket" spot in the New York Times served as both an advertisement for the firm's merchandise and an imperative for consumers to reduce their carbon footprint. The ad's message leveraged an anti-consumerist ideology to encourage the purchase of long-lasting outdoor apparel and deter the proliferation of the fast fashion industry. Most large companies across the world have made commitments to climate change. For example:
Amazon announced in 2019 that it would transition to 80% renewable energy usage by 2024, and then to zero emissions by 2030. The firm's CEO Jeff Bezos also launched the Bezos Earth Fund in February 2020, committing $10 billion to assist in "any effort that offers a real possibility to help preserve and protect the natural world".
Google announced in September 2020 that it is investing in manufacturing regions to create new carbon-free energy and help cities reduce their emissions.
Gun control
A number of major firearms sellers have modified their gun sales policies, particularly as a response to mass shootings taking place in the U.S. Two such notable examples are the following:
Ed Stack, CEO of Dick's Sporting Goods, announced in February 2018 that stores would end the sales of high-capacity magazines, as well as sales of guns to persons under the age of 21. The firm also took legal action by urging Congress to ban assault-style weapons, raise the minimum age to purchase a gun to 21, and outlaw sales of high-capacity magazines and bump stocks. The firm cited the Stoneman Douglas High School shooting in Parkland, Florida as an event that directly influenced its decisions.
Walmart CEO Doug McMillon released a statement containing news of the firm's plans to discontinue sales of short-barrel rifle ammunition, handgun ammunition, and handguns. This statement also requested that customers no longer openly carry firearms into Walmart or Sam's Club stores, including those in states in which “open carry” practices are permitted. The firm cited the 2019 El Paso shooting, which took place in a Walmart store, as a critical incident shaping its decisions.
Other domains
Firms have engaged in CSA in a number of other domains. Below are select examples.
Reproductive health care
M.A.C. Cosmetics has worked with Planned Parenthood since 2008 and contributed over $2 million to the organization. According to John Demsey, executive group president of the brand's parent company Estée Lauder, "It is so important for people of all ages, all races and all genders to get the accurate information and care they need so they can live their best, healthiest lives, but we see that a lot of people aren’t seeking that information and care because of stigmas that disproportionately affect women, people of color and the LGBTQ community."
Net neutrality
Burger King advocated for net neutrality with a January 2018 ad that illustrated the concept of paid prioritization through hamburger sales—customers were told they would have to wait longer for their food, unless they were willing to pay a premium for immediate service.
Gender non-discrimination
Target issued a statement in September 2016 encouraging store employees and patrons to use the restroom or fitting room facility that corresponds with their gender identity.
Immigration
In January 2017, nearly 100 Silicon Valley firms filed an amicus brief against the Trump administration's anti-immigration policy directed at refugees, travelers, and visa holders originating from predominantly Muslim portions of the world.
Controversial symbols
NASCAR announced in July 2020 that it would ban the Confederate flag from all its racing venues.
Potential business benefits
Research has uncovered the broader financial implications of CSA on firm value including improving firm's attractiveness to a wider segment of investors and customers. On average, investors respond negatively to CSA, though there are a number of factors that may buffer or even reverse this relationship. Most notably, a firm's CSA elicits positive abnormal stock returns when there is high alignment between the firm's CSA and the values of its stakeholders (e.g. customers, employees, and state legislators). In particular, researchers observed an increase in sales growth over the next quarter and year when CSA aligned with customer values.
A number of CSA characteristics have been shown to further heighten investor response: if the activism takes the form of an action, is announced by the CEO, is not justified by a business objective, and is announced alone (vs. in a coalition with other firms). Notably, managers may find it especially appropriate to engage in CSA if they are deeply committed to activism, and it aligns with their strategic objectives (i.e. acquiring a more liberal or conservative customer base). Still, CSA requires strategic deliberation. CSA activities may signal to stakeholders that the firm is willing to engage in risky behaviors and even divert resources from profit-generating activities. Given the enduring nature of activism, it is often plausible for investors to believe CSA serves as a value-based indication of a firm's future decisions, particularly those related to purpose, reputation, and relationship management.
Criticism and concerns
Critics have expressed concern about the degree to which CSA is helpful, either for advancing sociopolitical causes or as a firm activity more generally. By the mid-2010s, forms of rhetoric that were later retroactively labelled as "woke" had entered mainstream media and were being used in marketing and advertising; campaigns associated with this trend have been generally perceived by consumers as insincere and inauthentic, and have provoked cultural backlashes.
Cultural scientists Akane Kanai and Rosalind Gill described woke capitalism as a then-"dramatically intensifying" trend in which public relations pertains to the concerns of historically marginalized groups (such as in terms of race, gender and religion), using them as mascots in advertisements with messages of empowerment. On the one hand, this creates an individualized and depoliticized idea of social justice, using depictions of social action to signify an increase in self-confidence; on the other hand, the omnipresent visibility in advertising of minorities can also amplify a backlash against their equality. For people in lower economic strata, the equality of these minorities thus becomes indispensable to the maintenance of capitalism, with the minorities being seen as responsible for the losses of the system.
Woke-washing
The term woke-washing was used in 2019 by Alan Jope, chief executive of Unilever, who warned that brands which failed to take verifiable action on their rhetoric could "further destroy trust in our industry". Helen Lewis held the opinion that cancel culture is the result of what she calls "the iron law of woke capitalism", and believes that it is used for inexpensive messaging as a substitute for genuine reform. Will Hutton wrote that he believed woke capitalism is "the only way forward", citing principles of corporate responsibility. Alternatively, Elizabeth Bruenig observed that while woke capitalism has been seen as an evolution of capitalism that can create unprecedented benefits for the public good, it remains a form of capitalism and hence cannot be celebrated without aligning with capitalist interests; similarly, Andrew V. Abela held the opinion that it does little to actually further progressive causes.
A common argument is that firms are profit-seeking and thus care more about image and reputation than the causes they address. Some have referred to firms' political behavior as akin to "woke-washing", a pejorative term adapted from the similar concept of "greenwashing". Woke-washing is a critique leveraged against firms thought to "appropriate the language of social activism into marketing material". Critics have further argued that firms may utilize greater capital on the appearance of progressivism (i.e. through advertisements and promotional efforts) than on actual cause-related awareness or fundraising efforts. In such circumstances, activism has been criticized as a deceptive marketing tool for capturing demand among belief-driven consumers. Action-based follow-through could be important for fostering perceptions of authentic connection to supported sociopolitical causes. In a 2020 Harvard Business Review article, journalists Erin Dowell and Marlette Jackson said, "Empty company statements can seem to say that Black lives only matter to big business when there’s profit to be made." Others have argued whether firms should engage with sociopolitical issues at all. In particular, some critics have shunned the idea that market-based entities should influence or have a say in what is considered right and wrong.
Counter-movement
Beginning to a major degree in the 2020s, members of the American right have perpetuated efforts to boycott companies that openly support "woke" causes. The phrase "Go woke, go broke" has been an umbrella catchphrase to denote companies subject to boycotts against companies for "going woke" or engaging in activities like promoting diversity, equity, and inclusion or in the case of Bud Light maker AB InBev, partnering with transgender influencers. Many companies subject to "go woke go broke" campaigns, including AB InBev, Target, and the Walt Disney Company have seen declines in revenue, profit, and/or stock value as of a result of "go woke go broke" campaigns. Some figures in business, such as Mark Cuban, have defended companies engaging in "wokeness" by arguing that engaging in social justice causes reflects companies caring about their customers.
See also
Girl power
Hashtag activism
Managerial state
Pinkwashing
Rainbow capitalism
Slacktivism
Social justice warrior
Virtue signalling
References
External links
2020s anti-LGBTQ movement in the United States
Activism
Anti-LGBTQ sentiment
Applied ethics
Codes of conduct
Corporate social responsibility
Morality
Political controversies in the United States
Social conservatism in the United States
Social ethics
Social finance | Corporate sociopolitical activism | [
"Biology"
] | 3,692 | [
"Behavior",
"Human behavior",
"Applied ethics"
] |
65,877,318 | https://en.wikipedia.org/wiki/Boundary%20Butte%20%28Rainbow%20Plateau%29 | Boundary Butte is a 4,934-foot (1,504 meter) elevation sandstone summit located south of Lake Powell, in extreme southwestern San Juan County, Utah, United States, just north of the Arizona border. It is situated on Navajo Nation land, northeast of the town of Page, and towers 1,200 feet above the lake as a landmark of the area. It lies on the
Utah-Arizona border, hence its name.
Geology
Boundary Butte is a butte composed primarily of Entrada Sandstone, similar to Dominguez Butte to the north, and Tower Butte to the southwest. The Entrada Sandstone overlays Carmel Formation, and below that Page Sandstone at lake level. Above the Entrada layers is Romana Sandstone capped by Morrison Formation. It is located in the southern edge of the Great Basin Desert on the Colorado Plateau. Precipitation runoff from this feature drains into the Colorado River watershed.
Gallery
Climate
According to the Köppen climate classification system, Boundary Butte is located in an arid climate zone with hot, very dry summers, and chilly winters with very little snow. Spring and fall are the most favorable seasons to visit.
See also
Colorado Plateau
List of rock formations in the United States
References
External links
Weather forecast: National Weather Service
Colorado Plateau
Landforms of San Juan County, Utah
Geography of the Navajo Nation
Lake Powell
Buttes of Utah
One-thousanders of the United States
Sandstone formations of the United States | Boundary Butte (Rainbow Plateau) | [
"Engineering"
] | 287 | [
"Colorado River Storage Project",
"Lake Powell"
] |
65,879,198 | https://en.wikipedia.org/wiki/Drift%20waves | In plasma physics, a drift wave is a type of collective excitation that is driven by a pressure gradient within a magnetised plasma, which can be destabilised by differences between ion and electron motion (then known as drift-wave instability or drift instability). The equations which describe these waves a number of solutions, including ion-acoustic solitary waves, and are roughly analogous to modons.
The drift wave typically propagates across the pressure gradient and is perpendicular to the magnetic field. It can occur in relatively simple configurations such as in a column of plasma with a non-uniform density but a straight magnetic field. Drift wave turbulence is responsible for the transport of particles, energy and momentum across magnetic field lines.
The characteristic frequency associated with drift waves involving electron flow is given by
where is the wavenumber perpendicular to the pressure gradient of the plasma, is the Boltzmann constant, is the electron temperature, is the elementary charge, is the background magnetic field and is the number density gradient of the plasma.
References
Waves in plasmas | Drift waves | [
"Physics"
] | 212 | [
"Waves in plasmas",
"Physical phenomena",
"Plasma physics",
"Plasma phenomena",
"Waves",
"Plasma physics stubs"
] |
65,880,896 | https://en.wikipedia.org/wiki/N-t-BOC-MDMA | N-t-BOC-MDMA is a chemical compound which can be both a synthetic precursor to, or a prodrug of the empathogenic drug MDMA. It was first identified in Australia in 2015 as a seizure by customs, and has subsequently been found in China, the Netherlands and other European countries. Originally it was thought to be intended as a non-illegal form of MDMA which could be easily converted into the prohibited final product after importation, however one seizure by police found N-t-BOC-MDMA in the process of being pressed into pills, and experiments with simulated gastric fluid confirmed that it can be broken down to MDMA by human stomach acid. Similar N-protected compounds such as N-t-BOC-methamphetamine, N-p-tosyl-methamphetamine, N-t-BOC-ketamine, N-t-BOC-norketamine, and N-methoxycarbonyl-MDA have also been encountered by law enforcement.
Legal status
N-t-BOC-MDMA has been specifically listed as an illicit drug in Singapore and South Korea, but is also likely to be controlled by general drug analogue laws in various other countries.
See also
1-Boc-4-AP - a masked fentanyl precursor
Gabapentin enacarbil
O-Acetylpsilocin
Lys-MDA
NBoc-DMT
Phenatine
References
Substituted amphetamines
Designer drugs
Entactogens and empathogens
Prodrugs | N-t-BOC-MDMA | [
"Chemistry"
] | 330 | [
"Chemicals in medicine",
"Prodrugs"
] |
65,885,589 | https://en.wikipedia.org/wiki/Cistercian%20numerals | The medieval Cistercian numerals, or "ciphers" in nineteenth-century parlance, were developed by the Cistercian monastic order in the early thirteenth century at about the time that Arabic numerals were introduced to northwestern Europe. They are more compact than Arabic or Roman numerals, with a single glyph able to indicate any integer from 1 to 9,999.
Digits are based on a horizontal or vertical stave, with the position of the digit on the stave indicating its place value (units, tens, hundreds or thousands). These digits are compounded on a single stave to indicate more complex numbers. The Cistercians eventually abandoned the system in favor of the Arabic numerals, but marginal use outside the order continued until the early twentieth century.
History
The digits and idea of forming them into ligatures were apparently based on a two-place (1–99) numeral system introduced into the Cistercian Order by John of Basingstoke, archdeacon of Leicester, who it seems based them on a twelfth-century English shorthand (ars notaria). In its earliest attestations, in the monasteries of the County of Hainaut, the Cistercian system was not used for numbers greater than 99, but it was soon expanded to four places, enabling numbers up to 9,999.
The two dozen or so surviving Cistercian manuscripts that use the system date from the thirteenth to the fifteenth century, and cover an area from England to Italy, Normandy to Sweden. The numbers were not used for arithmetic, fractions or accounting, but indicated years, foliation (numbering pages), divisions of texts, the numbering of notes and other lists, indexes and concordances, arguments in Easter tables, and the lines of a staff in musical notation.
Although mostly confined to the Cistercian order, there was some usage outside it. A late-fifteenth-century Norman treatise on arithmetic used both Cistercian and Indo-Arabic numerals. In one known case, Cistercian numerals were inscribed on a physical object, indicating the calendrical, angular and other numbers on the fourteenth-century astrolabe of Berselius, which was made in French Picardy.
After the Cistercians had abandoned the system, marginal use continued outside the order. In 1533, Heinrich Cornelius Agrippa von Nettesheim included a description of these ciphers in his Three Books of Occult Philosophy.
The numerals were used by wine-gaugers in the Bruges area at least until the early eighteenth century.
In the late eighteenth century, Chevaliers de la Rose-Croix of Paris briefly adopted the numerals for mystical use, and in the early twentieth century Nazis considered using the numerals as Aryan symbolism.
The modern definitive expert on Cistercian numerals is the mathematician and historian of astronomy, David A. King.
Form
A horizontal stave was most common while the numerals were in use among the Cistercians. A vertical stave was attested only in Northern France in the fourteenth and fifteenth centuries. However, eighteenth- and twentieth-century revivals of the system in France and Germany used a vertical stave. There is also some historical variation as to which corner of the number represented which place value. The place-values shown here were the most common among the Cistercians and the only ones used later.
Using graphic substitutes with a vertical stave, the first five digits are 1, 2, 3, 4, 5. Reversing them forms the tens, 10, 20, 30, 40, 50. Inverting them forms the hundreds, 100, 200, 300, 400, 500, and doing both forms the thousands, 1,000, 2,000, 3,000, 4,000, 5,000. Thus (a digit 1 at each corner) is the number 1,111. (The exact forms varied by date and by monastery. For example, the digits shown here for 3 and 4 were in some manuscripts swapped with those for 7 and 8, and the 5's may be written with a lower dot ( etc.), with a short vertical stroke in place of the dot, or even with a triangle joining to the stave, which in other manuscripts indicated a 9.)
Horizontal numbers were the same, but rotated 90 degrees counter-clockwise. (That is, for 1, for 10, for 100—thus for 101—and for 1,000, as seen above.)
Omitting a digit from a corner meant a value of zero for that power of ten, but there was no digit zero. (That is, an empty stave was not defined.)
Higher numbers
When the system spread outside the order in the fifteenth and sixteenth centuries, numbers into the millions were enabled by compounding with the digit for "thousand". For example, a late-fifteenth century Norman treatise on arithmetic indicated 10,000 as a ligature of "1,000" wrapped under and around "10" (and similarly for higher numbers), and Noviomagus in 1539 wrote "million" by subscripting "1,000" under another "1,000". A late-thirteenth-century Cistercian doodle had differentiated horizontal digits for lower powers of ten from vertical digits for higher powers of ten, but that potentially productive convention is not known to have been exploited at the time; it could have covered numbers into the tens of millions (horizontal 100 to 103, vertical 104 to 107). A sixteenth-century mathematician used vertical digits for the traditional values, horizontal digits for millions, and rotated them a further 45° counter-clockwise for billions and another 90° for trillions, but it is not clear how the intermediate powers of ten were to be indicated and this convention was not adopted by others.
The Ciphers of the Monks
The Ciphers of the Monks: A Forgotten Number-notation of the Middle Ages, by David A. King and published in 2001, describes the Cistercian numeral system.
The book received mixed reviews. Historian Ann Moyer lauded King for re-introducing the numerical system to a larger audience, since many had forgotten about it. Mathematician Detlef Spalt claimed that King exaggerated the system's importance and made mistakes in applying the system in the book devoted to it. Moritz Wedell, however, called the book a "lucid description" and a "comprehensive review of the history of research" concerning the monks' ciphers.
Notes
References
External links
FRB Cistercian font (OTF) at GitHub. Uses the Private Use Area, since Unicode has declined to assign character codes. Font characters are segments, to be combined into the complete numerals.
Cistercian number generator at dCode. Uses digit shapes similar to the astrolabe (vertical stave, triangular 5).
L2/20-290 Background for Unicode consideration of Cistercian numerals
Cistercian Web Component for use on web pages. Includes a live updating Cistercian numeral clock.
Numeral systems
13th-century introductions
Writing systems introduced in the 2nd millennium | Cistercian numerals | [
"Mathematics"
] | 1,465 | [
"Cistercian numerals",
"Numeral systems",
"Mathematical objects",
"Numbers"
] |
73,094,453 | https://en.wikipedia.org/wiki/Video%20chapter | Video chapters on online video platforms divide the videos into sections, with each section having a specific "chapter title", most notably YouTube. Most services offer a manual way to add chapter sections and title them, several platforms also offer automatic tools for this. The purpose is to aid the navigation of the video as well as to encourage video creators to structure the videos coherently. Both of these goals aid users in general, and in particular can be beneficial to persons with disabilities.
Online learning platforms - such as Coursera - were some of the early adopters of chapters marks in the videos that form part of their curricula as a way to aid navigation, and convey the structure of the lectures and their subject matter.
Accessibility
As with many other forms of structured (meta) data, video chapters can improve web accessibility. In particular, it can help persons with disabilities such as visual and hearing impairments. Also as with many other forms of structured (meta) data, the advantages to persons with disabilities are a function of the quality of the metadata (poor quality can instead be detrimental).
Automatic generation
Several online platforms offer automatic generation of chapters, including the detection of the segments, and the labeling of the segments with chapter titles. Video chapter generation as a machine learning problem statement is also conducted academically.
Open-source models
Several open-source models for automatic segmentation have been described. Video segmentation information is typically processed by means of large language models, or combined with video Optical character recognition information, detecting the largest text in a slide (typically the title), to be used as the chapter title.
Video editor support
Several (offline) video editors such as Final Cut Pro, Adobe Premiere Pro, Shotcut, and OpenShot have support for chapter marks, that can directly be directly uploaded to online video platforms.
See also
Vimeo
Microsoft Stream
References
Web accessibility
Video hosting
Components of intellectual works
Accessible information
Web design
Usability | Video chapter | [
"Technology",
"Engineering"
] | 387 | [
"Components of intellectual works",
"Design",
"Web design",
"Components"
] |
73,096,333 | https://en.wikipedia.org/wiki/HD%20149404 | HD 149404, also known as HR 6164 and V918 Scorpii, is a star about 4,300 light years from the Earth, in the constellation Scorpius. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a rotating ellipsoidal variable, a binary star for which the two stars' combined brightness varies slightly, from magnitude 5.42 to 5.50, during their 9.8 day orbital period. It is one of the brightest members of the Ara OB1 association, which has the open cluster NGC 6193 at its center.
The brightness variability of HD 149404 was marginally detected by the Argentinian astronomer Alenjandro Feinstein, during a photoelectric photometry study undertaken from 1963 through 1965. It was given the variable star designation V918 Scorpii in 1980. In 1977, Peter Conti et al. discovered that HD 149404 has double spectral lines, implying it is a spectroscopic binary. Philip Massey and Peter Conti derived the first set of orbital elements for the binary system, in 1979.
The secondary star in the HD 149404 system is believed to have originally been the more massive of the two, but it is now less massive than the primary due to mass transfer caused by Roche lobe overflow in the past. The secondary may still be close to filling its Roche lobe. It is a rare ON supergiant, a star with unusually strong absorption lines of nitrogen in its stellar spectrum. Spectroscopic studies show that both stars have a stellar wind and a shock is formed where the two winds collide, which produces emission line features.
References
Scorpius
081305
006164
Scorpii, V918
Binary stars
Rotating ellipsoidal variables
O-type supergiants
Emission-line stars | HD 149404 | [
"Astronomy"
] | 393 | [
"Scorpius",
"Constellations"
] |
73,097,353 | https://en.wikipedia.org/wiki/Hericium%20novae-zealandiae | Hericium novae-zealandiae is a species of fungus in the Hericiaceae family. Formerly classified as Hericium coralloides which shares an almost identical morphology. Being saprotrophic, H. novae-zealandiae can be observed growing from dead, decaying wood. Also known as pekepekekiore, it is endemic to New Zealand and was consumed by indigenous Māori.
Description
Hericium novae-zealandiae has a relatively large (10 cm + diameter), white fruiting body, initially described (as Hydnum nova zealandia) as looking somewhat like a cauliflower nearing flowering. Lacking a pileus or defined stipe, basidiomata are highly and irregularly branched. Growing from a short, corkish stem, culminating in numerous, densely arranged, fine tips. The hymenium (spore bearing surface) is located on the surface of the fine tips, there is no delineation between the stipe and the hymenium until spore maturity when tips become reddish.
Medicinal
The closely related Hericium erinaceus, or lion's mane has been shown to have numerous health benefits including treating dyspepsia, gastric ulcers as well as antitumor and immuno-modulatory activity.
Extractions from Hercium novae-zealandiae have been shown to exhibit antiproliferative qualities when applied to three prostate cancer lines cancer lines (DU145, LNCaP and PC3). While a polysacharride extract was effective on LNCaP and PC3 lines, an ethanol extract containing the constituents hericenone C, hericene B, ergosterol and ergosterol peroxide was effective on all three. The mechanism in both cases was identified as apoptosis (programmed cell death).
References
External links
Fungi of New Zealand
Edible fungi
Fungi in cultivation
Fungi described in 2019
Russulales
Fungus species | Hericium novae-zealandiae | [
"Biology"
] | 400 | [
"Fungi",
"Fungus species"
] |
73,097,672 | https://en.wikipedia.org/wiki/Outfox%20the%20Market | Outfox the Market, the trading name of Foxglove Energy Supply, is a British energy supplier based in Leicester, United Kingdom. It was founded in 2017.
History
In 2019, the Advertising Standards Authority upheld a complaint against Outfox the Market, which forbade it from publishing false claims to the cheapest supplier in the UK, or the cheapest green energy supplier in the UK.
In 2021, it came top in a Which? customer satisfaction survey.
In July 2022, it came second in a survey by Citizens Advice. However, later in the same month, energy regulator Ofgem criticised the company for failing to take action on customer's direct debit problems.
In December 2022, Ofgem served the company with a notice of failure to comply with a confirmed Provisional Order within the meaning of section 25 of the Electricity Act 1989 and section 28 of the Gas Act 1986.
The notice, issued because of Ofgem's concerns over the company's financial viability, forbade Foxglove from taking on any new customers, or taking any money out of the company. In June 2023, the ban on new customers was lifted; however the company was still restricted from making any non-essential payments.
In July 2023, Outfox the Market was fined £1.8 million for repeatedly failing to provide Ofgem with appropriate financial data when required.
References
External links
British companies established in 2017
Electric power companies of the United Kingdom
Renewable resource companies established in 2017
Renewable energy companies of the United Kingdom
Utilities of the United Kingdom
Electric power companies
Energy companies established in 2017
Companies based in Leicester | Outfox the Market | [
"Engineering"
] | 327 | [
"Electrical engineering organizations",
"Electric power companies"
] |
73,098,022 | https://en.wikipedia.org/wiki/Mechanics%20of%20Advanced%20Composite%20Structures | Mechanics of Advanced Composite Structures is a biannual peer-reviewed open-access scientific journal published by Semnan University. The editor-in-chief is Abdoulhossein Fereidoon (Semnan University). The journal covers all aspects of research on composite structures. It was established in 2014 and is abstracted and indexed in Scopus.
References
External links
Academic journals established in 2014
Quarterly journals
English-language journals
Creative Commons Attribution-licensed journals
Materials science journals | Mechanics of Advanced Composite Structures | [
"Materials_science",
"Engineering"
] | 101 | [
"Materials science stubs",
"Materials science journals",
"Materials science journal stubs",
"Materials science"
] |
73,098,119 | https://en.wikipedia.org/wiki/Stem%20cell%20laws%20and%20policy%20in%20Iran | Iran's flexible approach towards stem-cell research is linked to the Shia tradition being flexible enough to allow for ESCs science; the second is that the approval of ESCs research was made easier by permissive laws governing other areas of biomedicine, such as new assisted reproductive technologies; and the third is that Iran's lack of a public discussion of bioscience affects how its ESCs research policy is seen.
In 2002 a fatwa was issued by the Supreme Leader of Iran regarding the permissibility of "destruction of residual embryos from the in vitro fertilization cycle for the purpose of obtaining stem cells for research purposes" as accreditation for the country's ESCs scientific community. Following this positive fatwa, the stem cell department of the Royan Institute in Tehran was established in the same year to establish the ESCs lines and to develop techniques to differentiate these lineages into various mature cell types including cardiomyocytes, B cells, and neurons.
Cultural and sociological context
In the case of Iran, the introduction of the Islamic system appears to have forced religious scholars to assume an unprecedented role of responsibility and engagement. Social Planning and Public Health. The large-scale crises may partially explain why religious scholars quoted Maslahat and Istihsan in their decisions on medicine and health problems rather than looking at those problems in isolation or in the theoretical sense as it happened in the past.
The financial burden of devastating diseases is also at the heart of hESC research decisions in Iran. This may have given Shia scholars a boost to reconsider the degenerative and public health implications of terminal disorders or economic hardships causing serious and long-lasting illnesses for individuals, families, and society. The eight-year Iran-Iraq war has left the country with a large disabled community, due in part to spinal cord injuries, which has been an intense motivation for Iran to start many cell therapy research projects.
Even in developing countries (e.g. Iran), home cell therapy and regenerative medicine are cost-effective solutions for the growing number of patients with chronic diseases including diabetes, heart disease, and hepatitis blood diseases such as thalassemia, which are relatively common.
Sanctions
Although Iran has a liberal domestic regulatory environment and its scientists are well-funded, the country cannot import scientific equipment and materials that most stem cell scientists use on a daily basis. This is largely due to trade sanctions imposed on Iran by other countries, including the United States and the European Community, which ban the export of certain scientific equipment to Iran and require other special export permits.
See also
Stem cell laws and policy in China
Stem cell laws
Stem cell controversy
Stem cell laws and policy in the United States
References
Biotechnology law
Medical law | Stem cell laws and policy in Iran | [
"Biology"
] | 547 | [
"Biotechnology law"
] |
73,098,277 | https://en.wikipedia.org/wiki/Factorization%20algebra | In mathematics and mathematical physics, a factorization algebra is an algebraic structure first introduced by Beilinson and Drinfel'd in an algebro-geometric setting as a reformulation of chiral algebras, and also studied in a more general setting by Costello and Gwilliam to study quantum field theory.
Definition
Prefactorization algebras
A factorization algebra is a prefactorization algebra satisfying some properties, similar to sheafs being a presheaf with extra conditions.
If is a topological space, a prefactorization algebra of vector spaces on is an assignment of vector spaces to open sets of , along with the following conditions on the assignment:
For each inclusion , there's a linear map
There is a linear map for each finite collection of open sets with each and the pairwise disjoint.
The maps compose in the obvious way: for collections of opens , and an open satisfying and , the following diagram commutes.
So resembles a precosheaf, except the vector spaces are tensored rather than (direct-)summed.
The category of vector spaces can be replaced with any symmetric monoidal category.
Factorization algebras
To define factorization algebras, it is necessary to define a Weiss cover. For an open set, a collection of opens is a Weiss cover of if for any finite collection of points in , there is an open set such that .
Then a factorization algebra of vector spaces on is a prefactorization algebra of vector spaces on so that for every open and every Weiss cover of , the sequence
is exact. That is, is a factorization algebra if it is a cosheaf with respect to the Weiss topology.
A factorization algebra is multiplicative if, in addition, for each pair of disjoint opens , the structure map
is an isomorphism.
Algebro-geometric formulation
While this formulation is related to the one given above, the relation is not immediate.
Let be a smooth complex curve. A factorization algebra on consists of
A quasicoherent sheaf over for any finite set , with no non-zero local section supported at the union of all partial diagonals
Functorial isomorphisms of quasicoherent sheaves over for surjections .
(Factorization) Functorial isomorphisms of quasicoherent sheaves
over .
(Unit) Let and . A global section (the unit) with the property that for every local section (), the section of extends across the diagonal, and restricts to .
Example
Associative algebra
Any associative algebra can be realized as a prefactorization algebra on . To each open interval , assign . An arbitrary open is a disjoint union of countably many open intervals, , and then set . The structure maps simply come from the multiplication map on . Some care is needed for infinite tensor products, but for finitely many open intervals the picture is straightforward.
See also
Vertex algebra
References
Abstract algebra | Factorization algebra | [
"Mathematics"
] | 611 | [
"Abstract algebra",
"Algebra"
] |
73,100,899 | https://en.wikipedia.org/wiki/Ministry%20of%20Energy%20and%20Mines%20%28Dominican%20Republic%29 | The Ministry of Energy and Mining (Spanish: Ministerio de Energía y Minas) of the Dominican Republic is a government institution in charge of the responsible development of the country's energy and mining sectors. Its main concern is to keep a reliable energy infrastructure and preserve an adequate exploitation of the country's minerals.
This office appeared on 2013 with its current name as a separate institution from the Ministry of Industry and Trade. Its headquarters are located at Santo Domingo. Its Minister is Antonio Almonte, since August 16, 2020.
History
By 1920, electricity in the Dominican Republic was provided by foreign-investment companies. On 1928, the government created the Santo Domingo Electric Company (Compañía Eléctrica de Santo Domingo), given the first steps to the national electric system. Through 1954 and 1955, the Dominican government focused on acquiring companies dedicated to the generation and distribution of electricity, and created the Dominican Electric Corporation (Corporación Dominicana de Electricidad or CDE) on 1955 by Decree no. 555.
On 1966, with the creation of the Secretary of State of Industry and Trade (Secretaría de Estado de Industria y Comercio), all matters related to energy and mining were put under this office.
On June 4, 1971, Congress signed Law 146-71 about the mining sector.
On July 3, 2013, by Law 100–13, the Dominican government formally created the Ministry of Energy and Mining (Ministerio de Energía y Minas) as the regulator of the energy policies and the nation's mining.
Internal structure
As the other Ministries of the Dominican Republic, the Ministry of Energy and Mining is subdivided into vice-ministries. These are:
Vice-ministry of Government Energy Saving
Vice-ministry of Energy
Vice-ministry of Nuclear Energy
Vice-ministry of Hydrocarbons
Vice-ministry of Mining
Vice-ministry of Energy Safety and Infrastructure
Affiliated agencies
The Ministry of Energy and Mining has several institutions affiliated to it. These are:
National Commission of Energy (Comisión Nacional de Energía or CNE)
Superintendency of Electricity (Superintendencia de Electricidad)
General Office of Mining (Dirección General de Minería)
National Geologic Service (Servicio Geológico Nacional)
The Dominican Corporations of State's Electric Companies (Corporación Dominicana de Empresas Eléctricas Estatales or CDEEE) was dissolved and integrated to this Ministry on 2020.
References
External links
Official website
Government of the Dominican Republic
Economy of the Dominican Republic | Ministry of Energy and Mines (Dominican Republic) | [
"Engineering"
] | 506 | [
"Energy organizations",
"Energy ministries"
] |
73,101,628 | https://en.wikipedia.org/wiki/Union%20theorem | The union theorem is a result from the 60s in computational complexity theory. It was published in 1969 by Ed McCreight and Albert Meyer.
Originally it is stated for general Blum complexity classes, but it is most relevant for DTIME, NTIME, DSPACE or NSPACE as stated in ch. 12.6 of first edition from 1979 of the textbook of Hopcroft and Ullman. This chapter was removed from newer editions, however.
The theorem for time complexity roughly states the following. Given a list of monotonically increasing time bound functions where for , there exists a time bound function such that a problem is computable in time bounded by if and only if there exists an such that the problem is computable in time bounded by .
The theorem can be applied to show that complexity classes like P are well-defined. Together with the speedup theorem, the gap theorem and the time and space hierarchy theorems it is a basis for hierarchies in complexity theory.
References
Computational complexity theory | Union theorem | [
"Mathematics"
] | 205 | [
"Theorems in computational complexity theory",
"Theorems in discrete mathematics"
] |
73,105,923 | https://en.wikipedia.org/wiki/Dimitra%20Markovitsi | Dimitra Markovitsi is a Greek-French photochemist. She is currently an Emeritus Research Director at the French National Center for Scientific Research (CNRS). She pioneered studies on the electronically excited states of liquid crystals and made significant advances to the understanding of processes triggered in DNA upon absorption of UV radiation. The two facets of her work have been the subject of a recent Marie Skodowska Curie European training network entitled "Light DyNAmics - DNA as a training platform for photodynamic processes in soft materials."
Early life
1954 marks the birth of Markovitsi, daughter of Tryfon and Eleftheria, in Athens. From 1958 to 1969, she resided at Krya Vrysi, Pella. Then she returned to Athens, where she finished with a degree in chemical engineering from the National Technical University (1978). Thanks to a scholarship from the French government, she relocated to France, where she earned a "Diplôme d'Etudes Approfondies" (equivalent to a Master's degree) in 1979 on "Energy and Pollution" from the Université Paris VII and, later, a Ph.D. in Chemistry from the Louis Pasteur University at Strasbourg (1983).
Research work
Dimitra Markovitsi's areas of research interest include photophysics and photochemistry in the condensed phase, time-resolved optical spectroscopy (absorption, fluorescence), excited states, energy, and charge transfer, charge separation, ionization, radical formation, photodamage, UV-induced primary processes in DNA (excited states, intrinsic fluorescence, electron ejection, oxidative damage) and G-quadruplexes.
Markovitsi studied the dimensionality of excitation transport in columnar phases. She discussed the effect of orientational disorder on the electronic excited states and introduced a model based on the exciton theory and quantum chemistry computations.
She published the first studies investigating the effect of structural disorder on the excited states of double helices and guanine quadruplexes. Simultaneously, she explored the behavior of the intrinsic DNA fluorescence from femtoseconds to nanoseconds. She provided evidence of the occurrence of excitation transport between nucleobases and the collective nature of Franck-Condon states. She reported the first spectroscopic investigation on DNA excited states in the UVA region; despite their very poor absorption, such excited states may contribute to the deterioration of the genetic code by solar light, whose UVA intensity is greater than that of UVB and UVC.
She identified an unanticipated phenomenon: low-energy UV radiation can ionize DNA multimers (but not their monomeric components), generating electron holes in the nucleobases. The latter radical species are precursors of oxidative damage and provide promise for nanodevices based on photoconductivity. She demonstrated that the photoionization of guanine quadruplexes can be adjusted by varying their structural parameters.
Markovitsi also investigated DNA reaction dynamics on nanosecond to millisecond timescales. This work focuses on the dimerization of nucleobases and the deprotonation and tautomerization of the guanine radical. Her research revealed the anisotropic character of such events, which are highly dependent on the local DNA environment, rendering the conventional models of chemical kinetics inadequate for describing them.
Markovitsi’s work has been published in collective books, including the “Handbook of Organic Photochemistry and Photobiology.
Career
While at Strasbourg in 1981, Markovitsi joined the CNRS. Then she relocated to the Paris area, where she worked from 1985 until 2021 in the CEA Paris-Saclay, in joint research Laboratories of the CNRS and the French Alternative Energies and Atomic Energy Commission. From 2001 to 2014, she was the director of the Francis Perrin Laboratory (Laboratoire Francis Perrin). After being appointed Emeritus Research Director, she moved to the Institut de Chimie Physique - Université Paris-Saclay.
Markovitsi served as president of the European Photochemistry Association from 2007 to 2010, and since 2014 she is the president of the International Foundation for Photochemistry.
Relevant publications
D. Markovitsi, On the Use of the Intrinsic DNA Fluorescence for Monitoring Its Damage: A Contribution from Fundamental Studies. 2024,https://doi.org/10.1021/acsomega.4c02256
D. Markovitsi, Processes triggered in guanine quadruplexes by direct absorption of UV radiation: From fundamental studies toward optoelectronic biosensors, Photochem. Photobiol. 2023, https://doi.org/10.1111/php.13826
Balanikas, E.; Banyasz, A.; Baldacchino, G.; Markovitsi, D. Deprotonation Dynamics of Guanine Radical Cations. Photochem. Photobiol. 2022, 98, 523-531.
Gustavsson, T.; Markovitsi, D. Fundamentals of the Intrinsic DNA Fluorescence. Acc. Chem. Res. 2021, 54, 1226-1235.
Balanikas, E.; Banyasz, A.; Douki, T.; Baldacchino, G.; Markovitsi, D. Guanine Radicals Induced in DNA by Low-Energy Photoionization. Acc. Chem. Res. 2020, 53, 1511–1519.
Banyasz, A.; Vay, I.; Changenet-Barret, P.; Gustavsson, T.; Douki, T.; Markovitsi, D. Base-pairing enhances fluorescence and favors cyclobutane dimer formation induced upon absorption of UVA radiation by DNA. J. Am. Chem. Soc. 2011, 133, 5163-5165.
Ecoffet, C.; Markovitsi, D.; Millie, P.; Lemaistre, J. Electronic excitations in organized molecular systems. A model for columnar aggregates of ionic compounds. Chem. Phys. 1993, 177, 629-643.
Other activities
Dimitra Markovitsi and her husband Gérard Balland translated from Greek into French the historical novel “Σέργιος και Βάκχος” by M. Karagatsis, appeared on 1959.
References
1954 births
Living people
Photochemists
20th-century women scientists | Dimitra Markovitsi | [
"Chemistry"
] | 1,382 | [
"Photochemists",
"Physical chemists"
] |
73,108,245 | https://en.wikipedia.org/wiki/Pleurotus%20smithii | Pleurotus smithii is a species of fungus in the family Pleurotaceae, described as new to science by mycologist Gastón Guzmán in 1975. Like other species of the Pleurotus cystidiosus clade, it has an anamorphic form, named Antromycopsis guzmanii. P. smithii can be distinguished from P. cystidiosus by lack of pleurocystidia or them being only present in young stages as cystidioid elements, short hyphal segments of the conidiophores in the anamorph, and long subcylindrical cheilocystidia in the teleomorph form.
See also
List of Pleurotus species
References
External links
Fungi described in 1975
Pleurotaceae
Fungus species | Pleurotus smithii | [
"Biology"
] | 165 | [
"Fungi",
"Fungus species"
] |
73,108,763 | https://en.wikipedia.org/wiki/Geometric%20drawing | Geometric drawing consists of a set of processes for constructing geometric shapes and solving problems with the use of a ruler without graduation and the compass (drawing tool). Modernly, such studies can be done with the aid of software, which simulates the strokes performed by these instruments.
For ancient mathematicians, geometry could not do without the methods of geometric constructions, necessary for understanding, theoretical enrichment, and problem-solving.
The accuracy and precision required of geometric drawing make it an important ally in the application of geometric concepts in significant areas of human knowledge, such as architecture, engineering, industrial design, among others.
The process of geometric drawing is based on constructions with a ruler and compass, which in turn are based on the first three postulates of Euclid's Elements.
The historical importance of rulers and compasses as instruments in solving geometric problems leads many authors to limit Geometric Drawing to the representation and solution of geometric figures in the plane.
With the development of computer-aided design (CAD) programs, geometric drawing has become more important in teaching-learning processes (development of spatial faculties) than the more imprecise tracing offered by rulers and compasses, when taking into account the precision of computer systems.
See also
Graphic design
Technical drawing
References
General references
External links
Euclid's Elements
Download Ruler and Compass 1.8 (software for building geometric figures with ruler and compass)
Drawing
Drawing | Geometric drawing | [
"Mathematics"
] | 280 | [
"Geometry"
] |
73,109,570 | https://en.wikipedia.org/wiki/Macroamylasemia | Macroamylasemia is the presence of macroamylase in the blood. Macroamylase is a complex of the enzyme amylase bound to other proteins forming a larger molecule. Macroamylase is typically composed of immunoglobulin A (IgA, 70%) and less often of immunoglobulin G (IgG, 30%). The association of amylase with some drugs has also been reported.
The macroamylase molecules are unable to pass through the kidneys and are therefore retained in the blood, leading to elevated levels of amylase in the bloodstream. In contrast, amylase urine levels are normal.
Presentation
Macroamylasemia is usually a benign condition, and people usually do not experience any symptoms or health problems. In fact, it is often discovered incidentally during a routine blood test. However, in some rare cases, macroamylasemia can cause recurrent abdominal pain or other gastrointestinal symptoms.
Causes
Macroamylasemia is a relatively rare condition, and in most cases, the exact cause is unknown. It can occur in completely healthy individuals without symptoms, in association with autoimmune diseases (such as systemic lupus erythematosus) and other diseases (cancer or inflammatory diseases).
However, there are some risk factors that can increase the likelihood of developing the condition:
Autoimmune disorder, such as systemic lupus erythematosus (SLE), rheumatoid arthritis, and Sjögren's syndrome
Chronic liver disease, such as cirrhosis
Certain medications, including thiazide diuretics and opiates
Genetic factors: There may be a genetic component
Diagnosis
Diagnosis of macroamylasemia is typically made by measuring the amylase levels in the blood and urine and performing additional tests to confirm the presence of macroamylase.
Management
Treatment is usually not necessary unless the patient is experiencing symptoms or complications related to the condition.
References
Blood disorders
Metabolic disorders | Macroamylasemia | [
"Chemistry"
] | 401 | [
"Metabolic disorders",
"Metabolism"
] |
73,111,004 | https://en.wikipedia.org/wiki/Baik%E2%80%93Deift%E2%80%93Johansson%20theorem | The Baik–Deift–Johansson theorem is a result from probabilistic combinatorics. It deals with the subsequences of a randomly uniformly drawn permutation from the set . The theorem makes a statement about the distribution of the length of the longest increasing subsequence in the limit. The theorem was influential in probability theory since it connected the KPZ-universality with the theory of random matrices.
The theorem was proven in 1999 by Jinho Baik, Percy Deift and Kurt Johansson.
Statement
For each let be a uniformly chosen permutation with length . Let be the length of the longest, increasing subsequence of .
Then we have for every that
where is the Tracy-Widom distribution of the Gaussian unitary ensemble.
Literature
References
Combinatorics
Probability theorems | Baik–Deift–Johansson theorem | [
"Mathematics"
] | 169 | [
"Mathematical theorems",
"Theorems in combinatorics",
"Theorems in discrete mathematics",
"Combinatorics",
"Theorems in probability theory",
"Combinatorics stubs",
"Mathematical problems"
] |
73,112,824 | https://en.wikipedia.org/wiki/S/2022%20J%201 | S/2022 J 1 is a small outer natural satellite of Jupiter discovered by Scott S. Sheppard on 30 August 2022, using the 4.0-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center on 22 February 2023, after observations were collected over a long enough time span to confirm the satellite's orbit.
S/2022 J 1 is part of the Carme group, a tight cluster of retrograde irregular moons of Jupiter that follow similar orbits to Carme at semi-major axes between , orbital eccentricities between 0.2 and 0.3, and inclinations between 163 and 166°. It has a diameter of about for an absolute magnitude of 17.0. The moon has been observed for over 20 years, with the earliest known observation on 24 February 2003.
References
Carme group
Moons of Jupiter
Irregular satellites
20220830
Discoveries by Scott S. Sheppard
Moons with a retrograde orbit | S/2022 J 1 | [
"Astronomy"
] | 200 | [
"Astronomy stubs",
"Planetary science stubs"
] |
73,112,846 | https://en.wikipedia.org/wiki/S/2022%20J%202 | S/2022 J 2 is a small outer natural satellite of Jupiter discovered by Scott S. Sheppard on 15 October 2022 using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on 22 February 2023, after observations were collected over a long enough time span to confirm the satellite's orbit.
S/2022 J 2 is part of the Carme group, a tight cluster of retrograde irregular moons of Jupiter that follow similar orbits to Carme at semi-major axes between , orbital eccentricities between 0.2 and 0.3, and inclinations between 163 and 166°. With a diameter of about for an absolute magnitude of 17.5, it is one of Jupiter's smallest known moons with confirmed orbits.
References
Carme group
Moons of Jupiter
Irregular satellites
20221015
Discoveries by Scott S. Sheppard
Moons with a retrograde orbit | S/2022 J 2 | [
"Astronomy"
] | 193 | [
"Astronomy stubs",
"Planetary science stubs"
] |
73,112,865 | https://en.wikipedia.org/wiki/S/2022%20J%203 | S/2022 J 3 is a small outer natural satellite of Jupiter discovered by Scott S. Sheppard on 30 August 2022, using the 4.0-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center on 22 February 2023, after observations were collected over a long enough time span to confirm the satellite's orbit.
S/2022 J 3 is part of the Ananke group, a cluster of retrograde irregular moons of Jupiter that follow similar orbits to Ananke at semi-major axes between , orbital eccentricities between 0.1 and 0.4, and inclinations between 139 and 155°. It has a diameter of about for an absolute magnitude of 17.3. The moon has been observed for over 20 years, with the earliest known observation on 26 February 2003.
References
Ananke group
Moons of Jupiter
Irregular satellites
20220830
Discoveries by Scott S. Sheppard
Moons with a retrograde orbit | S/2022 J 3 | [
"Astronomy"
] | 202 | [
"Astronomy stubs",
"Planetary science stubs"
] |
73,113,732 | https://en.wikipedia.org/wiki/HR%202501 | HR 2501, also known as HD 49131 and HP Canis Majoris, is a star about 2,000 light years from the Earth, in the constellation Canis Major. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a variable star, whose brightness varies from magnitude 5.35 to 5.80 on a variety of timescales ranging from hours to hundreds of days.
In 1838, John Herschel discovered that HR 2501 is a double star, with a magnitude 8.4 companion 4.9 arc seconds away. The companion is a slightly less massive, cooler, and less luminous B-type main sequence star. It is also a chemically peculiar helium-weak star.
In 1977, Mikolaj Jerzykiewicz and Christiaan Sterken detected slight (0.12 magnitude) variability in the brightness of HR 2501 during their search for beta Cephei variable stars in the southern sky. Christoffel Waelkens et al. confirmed that HR 2501 is variable in 1983, and reported that it varied in brightness on a timescale of weeks to months, with no clear period. In 1986 it was given the variable star designation HP Canis Majoris. In 1998, Anne-Marie Hubert and Michele Floquet examined the Hipparcos data for HR 2501, and found that it exhibited outbursts in which the brightness increased by 0.35 magnitudes, with a rise time of 100 days and a decay time of 400 days.
In 1984, Christopher Corbally found that the spectrum HR 2501 shows Hα, Hβ, Hγ and Hδ emission features, which along with its spectral type makes it a Be star. Jacqueline Coté found that the IRAS data for HR 2501 showed excess (above what would be expected from the star's photosphere) 12 and 25 μ emission. She concluded that this infrared excess could be due to either a circumstellar dust shell located 21 stellar radii from HR 2501, with a temperature of about 585 K, or (more likely) free-free emission from circumstellar gas.
An extensive study of HR 2501, published in 2003 by Fabien Carrier and Gilbert Burki, found that the star exhibits several periodicities. The radial velocity varies by 20.5 km/sec with a period of hours. They confirm the roughly 500 day photometric period found earlier by Hubert and Floquet, and suggest these outbursts may arise from episodes of matter ejection from the star or disk formation. Finally, they found a low amplitude (0.065 magnitude) brightness oscillation with a period of 11.05 hours. Spectroscopic data were presented by Carrier and Burki which suggest that during the brightness outbursts, "blobs" of ejected matter can be detected moving through a Keplerian disk surrounding the star.
References
032385
049131
Canis Majoris, HP
Emission-line stars
Be stars
Lambda Eridani variables
Gamma Cassiopeiae variable stars
B-type main-sequence stars
2501
Canis Major | HR 2501 | [
"Astronomy"
] | 653 | [
"Canis Major",
"Constellations"
] |
70,248,666 | https://en.wikipedia.org/wiki/Bourgeanic%20acid | Bourgeanic acid is a fatty acid with the molecular formula C22H42O5. Bourgeanic acid is a lichen metabolite.
References
Further reading
Lichen products
Fatty acids | Bourgeanic acid | [
"Chemistry"
] | 43 | [
"Natural products",
"Lichen products",
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
70,248,854 | https://en.wikipedia.org/wiki/Obafluorin | Obafluorin is a β-lactone antibiotic with the molecular formula C17H14N2O7. Obafluorin is produced by the bacterium Pseudomonas fluorescens. Obafluorin is a inhibitor of serine hydroxymethyltransferase.
References
Further reading
Antibiotics
Beta-lactones
Transferase inhibitors
Catechols
Benzamides
4-Nitrophenyl compounds | Obafluorin | [
"Chemistry",
"Biology"
] | 87 | [
"Antibiotics",
"Biocides",
"Biotechnology products"
] |
70,249,124 | https://en.wikipedia.org/wiki/Samuel%20Yates%20%28storekeeper%29 | Samuel Yates (1829 – 14 September 1900) was an English-born New Zealander, who was a storekeeper, farmer and businessman in the far north of New Zealand in the later part of the 19th century. His land holdings were so extensive, he was known as the "King of the North".
Early life
Samuel Yates was born in London, England in 1829 to Saul Yates, a Jewish solicitor, and his wife, Sarah Isaacs. Yates was educated in Liverpool, where his paternal grandfather had been the minister of the first Jewish congregation there, and also Paris. In his later years, he alleged that he met Emperor Louis Napoleon during his time in Paris and acquired his autograph.
Commercial activity
Yates came to New Zealand, where he had family, in 1852 with his father. Expected to pursue a legal career he instead opened a store at Mangonui, on the Northland Peninsula. In the early 1860s, he moved further north, to Pārengarenga Harbour. Originally envisaging a short stay for a holiday, the area was to his liking and he opened a second store there. He became a prominent resident, building a large homestead at Paua, on the southern side of Pārengarenga Harbour. He was the only trader in the area for a number of years and was apparently well respected. He had a monopoly on the Kauri gum trade up until the late 1870s when a competitor set up at Te Kao.
In December 1880, Yates married Ngāwini Murray, also known as Annie; his wife was part-Māori, was from Pukepoto, near Kaitaia, and was well connected to the Te Rarawa and Te Aupōuri iwi (tribe) through her mother, Kateraina Te Kone. It was a fortuitous marriage; through his wife's relationships with her iwi, Yates purchased or leased a significant amount of land across the northern part of the Aupouri Peninsula. His holdings eventually ran from Te Kao to North Cape and across to the coast on the western side of the peninsula. This area, a total of about 150,000 acres, became known as Te Paki station. He was able to finance his acquisitions through his connections to the finance sector in Auckland.
Much of the acquired land was converted to pasture, on which livestock, in the form of cattle, sheep and horses, was stocked. Cottages for farmer workers were erected, along with other sheds and structures. A jetty was built to allow goods and livestock to be loaded onto ships for transportation south to Auckland. His business interests and the size of his property were such that he became known as the "King of the North".
Later life
As Yates aged, he left more of the running of Te Paki to his wife, who was several years his junior. By September 1900, his health was in decline and he decided to leave Pārengarenga for Auckland so that when he died, he could be interred in the Jewish section of the Symonds Street Cemetery. Sailing aboard the Paeroa, he died on 14 September 1900; the ship had only just departed Pārengarenga. He was survived by his wife, who oversaw his burial in Auckland, and the couple's eight children. Ngāwini Yates continued to run Te Paki station until her own death in 1910.
Notes
References
1829 births
1900 deaths
People from London
People from the Northland Region
New Zealand Jews
19th-century New Zealand businesspeople
New Zealand merchants
Burials at Symonds Street Cemetery
English emigrants to New Zealand
New Zealand people of English-Jewish descent
Kauri gum | Samuel Yates (storekeeper) | [
"Physics"
] | 732 | [
"Amorphous solids",
"Unsolved problems in physics",
"Kauri gum"
] |
70,250,038 | https://en.wikipedia.org/wiki/Caret | Caret () is the name used familiarly for the character provided on most QWERTY keyboards by typing . The symbol has a variety of uses in programming and mathematics. The name "caret" arose from its visual similarity to the original proofreader's caret, , a mark used in proofreading to indicate where a punctuation mark, word, or phrase should be inserted into a document. The ASCII standard (X3.64.1977) calls it a "circumflex"; the Unicode standard calls it a "circumflex accent", although it is no longer practicable for that purpose.
History
Typewriters
On typewriters designed for languages that routinely use diacritics (accent marks), there are two possible ways to type these: keys can be dedicated to precomposed characters (with the diacritic included); alternatively a dead key mechanism can be provided. With the latter, a mark is made when a dead key is typed but, unlike normal keys, the paper carriage does not move on and thus the next letter to be typed is printed under the accent. The symbol was originally provided in typewriters and computer printers so that circumflex accents could be overprinted on letters (as in or ).
Transposition into ISO/IEC 646 and ASCII
The incorporation of the circumflex symbol into ASCII is a consequence of this prior existence on typewriters: this symbol did not exist independently as a type or hot-lead printing character. The original 1963 version of the ASCII standard used the code point for an . However, the 1965 standard defined code point as one of five available for national variation, with the circumflex diacritic as the default and the up-arrow as one of the alternative uses. In 1967, the second revision of ASCII followed suit.
Overprinting to add an accent mark was not always supported well by printers, and was almost never possible on video terminals. The freestanding circumflex (which had come to be called a caret) quickly became reused for many other purposes, such as in computer languages and mathematical notation. As the mark did not need to fit above a letter any more, it became larger in appearance such that it can no longer be used to overprint an accent in most fonts. Accented letters eventually because widely supported by adding precomposed characters instead of using overprinting.
In Unicode the symbol is encoded as ; in HTML it may be used directly or inserted with . The combining character for use as a diacritic is , although precomposed characters (like ) are available for most European languages.
Uses
Programming languages
The symbol has many uses in programming languages, where it is typically called a caret. It can signify exponentiation, the bitwise XOR operator, string concatenation, and control characters in caret notation, among other uses. In regular expressions, the caret is used to match the beginning of a string or line; if it begins a character class, then the inverse of the class is to be matched.
ANSI C can transcribe the caret in the form of the trigraph , as the character was originally not available in all character sets and keyboards.
C++ additionally supports tokens like (for ) and (for ) to avoid the character altogether.
recommends that the character be transcribed as digraph when required.
Pascal uses the caret for declaring and dereferencing pointers.
In Smalltalk, the caret is the method return statement.
In C++/CLI, .NET reference types are accessed through a handle using the syntax.
In Apple's C extensions for Mac OS X and iOS, carets are used to create blocks and to denote block types.
Go uses it as a bitwise NOT operator.
Node.js uses the caret in package.json files to signify dependency resolution behavior being used for each particular dependency. In the case of Node.js, a caret allows any kind of update, unless it is seen as a "major" update as defined by semver.
Surrogate symbol for superscript and exponentiation
In mathematics, the caret can signify exponentiation (e.g. 3^5 for ) where the usual superscript is not readily usable (as on some graphing calculators). It is also used to indicate a superscript in TeX typesetting.
The use of the caret for exponentiation can be traced back to ALGOL 60, which expressed the exponentiation operator as an upward-pointing arrow, intended to evoke the superscript notation common in mathematics. The upward-pointing arrow is now used to signify hyperoperations in Knuth's up-arrow notation.
Escape character
It is often seen in caret notation to show control characters: for instance, means the control character with value 1.
The Windows command-line interpreter (cmd.exe) uses the caret to escape reserved characters (most other shells use the backslash). For example, to pass a 'less-than' sign as an argument to a program, one would type .
Upward-pointing arrow
In internet forums, on social networking sites such as Facebook, or in online chats, one or more carets may be used beneath the text of another post, representing an upward-pointing arrow to that post; in addition to the arrow usage, it can also mean that the user who posted the ^ agrees with the above post. Multiple carets may be used to indicate that the comment is replying to, or relating to, the post above that correlates with the number of carets used, or to "underscore" the correct portion of the previous post, or simply for emphasis.
A similar use has been adopted by programming language compilers, such as the Java compiler, to point out where a compilation error has occurred. The compiler prints out the faulty line of code and uses a single caret on the next line, padded by spaces, to give a visual indication of the error location.
See also
Caret as used in proofreading and typography
Hat operator, a notation used in mathematics and statistics, is sometimes called a caret
Notes
References
Typographical symbols | Caret | [
"Mathematics"
] | 1,305 | [
"Symbols",
"Typographical symbols"
] |
70,252,717 | https://en.wikipedia.org/wiki/Salicornia%20fruticosa | Salicornia fruticosa, synonym Sarcocornia fruticosa, is a species of glasswort in the family Amaranthaceae (pigweeds). It is native to southern Europe, north Africa, Western Asia and Yemen. It is a halophyte, a plant that can grow in saline conditions.
It is the main saltwort species used in making special pot ash made during Mesopotamian times to the early Islamic era – قَلَيّ qali – which is the basis for the word "alkali".
References
fruticosa
Halophytes
Flora of Southwestern Europe
Flora of Southeastern Europe
Flora of North Africa
Flora of Western Asia
Flora of Yemen | Salicornia fruticosa | [
"Chemistry"
] | 142 | [
"Halophytes",
"Salts"
] |
70,253,585 | https://en.wikipedia.org/wiki/Hittite%20plague | The Hittite Plague or Hand of Nergal was an epidemic, possibly of tularemia, which occurred in the mid-to-late 14th century BC.
Background
The Hittite Empire stretched from Turkey to Syria. The plague was likely an outbreak of Francisella tularensis which occurred along the Arwad-Euphrates trading route in the 14th century BC. Much of the ancient Near East suffered from outbreaks; however, Egypt and Assyria initiated a quarantine along their border, and they did not experience the epidemic.
Tularemia is a bacterial infection which is still a threat. It is also referred to as "rabbit fever" and it is a zoonotic disease which can easily pass from animals to humans. The most common way that it is spread is through various insects which hop between species, such as ticks. The symptoms of an infection range from skin lesions to respiratory failure. Without treatment the mortality rate is 15% of those infected. According to former microbiologist Siro Trevisanato, "Tularemia is rare in many countries today, but remains a problem in some countries including Bulgaria."
Epidemic
According to author Philip Norrie (How Disease Affected the End of the Bronze Age), there are three diseases most likely to have caused a post-Bronze Age societal collapse: smallpox, bubonic plague, and tularemia. The tularemia plague which struck the Hittites could have been spread by insects or infected dirt or plants, through open wounds, or by eating infected animals.
Hittite texts from the mid-14th century BC refer to the plague causing disabilities and death. Hittite King Muršili II wrote prayers seeking relief from the epidemic, which had lasted two decades and killed many of his subjects. The two kings who preceded him, Šuppiluliuma I and Šuppiluliuma's immediate heir, Arnuwanda II, had also succumbed to tularemia. Muršili had ascended to the throne because he was the last surviving son of Šuppiluliuma.
Muršili believed that the plague had been transmitted to the Hittites by Egyptian prisoners who had been paraded through the capital city, Hattusa. There is some evidence suggesting that the Egyptians suffered from tularemia in the years preceding 1322 BC. The Hittites apparently also suspected zoonotic transmission, because they banned the use of donkeys in caravans. Another theory of the plague's origin suggests that it originated with rams that the Hittites had taken as spoils of war, along with other animals, after the Hittites raided Simyra. Soon after the animals were brought into Hittite villages, the tularemia outbreak began.
Plague of Alashiya, "The Hand of Nergal"
The plague is mentioned in Amarna letter EA 35, a letter written in Akkadian from the ruler of Alashiya (Cyprus) to the Pharaoh of Egypt during the Amarna Period. It dates from between 1350 and 1325 BC. In it, the plague is specially named as The Hand of Nergal.
Use against the Arzawans
The disease was intentionally brought to western Anatolia in what is described as the "first known record of biological warfare". Shortly after the Hittites experienced the outbreak of disease, the Arzawans from western Anatolia believed the Hittites were weakened and attacked them. The Arzawans claimed that rams suddenly appeared (1320 and 1318 BC) and the Arzawans brought them into their villages. It is thought that the Hittites had sent rams diseased with tularemia to infect their enemies. The Arzawans became so weakened by the plague that they failed in their attempt to conquer the Hittites.
References
Hittite Empire
Hittite plague
Biological warfare
Epidemics
Ancient health disasters
Hattusa | Hittite plague | [
"Biology"
] | 785 | [
"Biological warfare"
] |
70,253,610 | https://en.wikipedia.org/wiki/XY%20Ursae%20Majoris | XY Ursae Majoris is a short period binary star system in the northern circumpolar constellation of Ursa Major. It is an eclipsing binary with a baseline apparent visual magnitude of 9.50. The system is located at a distance of 221.5 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −10 km/s. It has a relatively high proper motion, traversing the celestial sphere at the angular rate of ·yr−1.
The variability of this system was discovered by W. Strohmeier and its period was determined by R. Kippenhahn, with the findings announced in 1955. It was found to be a detached eclipsing binary system, and by 1963 a variable primary component had been noted. E. H. Geyer made intermittent light curve studies of the system starting with its discovery up until 1975, ascribing variability in the light curve to star spot activity on the primary component. The orbital period of the pair was determined to be , with the orbital plane inclined at an angle of 79.84° to the line of sight from the Earth.
By 1990, enough data had been collected to identify a long term variation of the period, and it was hypothesized this was caused by a third body in the system orbiting the close binary. The orbital period of this component was estimated to be ~30 years in 2001, then refined to 26.7 years by 2010. If the orbital plane of this component is the same as the inner pair, its mass would be 18% of the mass of the Sun. An alternative solution to the period change suggests magnetic activity causes shifts in the angular momentum of the system, but this is considered less likely.
This is a double-lined spectroscopic binary star system with an orbital period of . The primary component is a G-type main-sequence star with a stellar classification of G2V. It is an RS Canum Venaticorum-type variable that is magnetically active and a bright X-ray source. Despite this, relatively few optical flares have been observed. The cooler secondary is a K-type main-sequence star of class K5V that is smaller and less massive than the primary.
References
Further reading
G-type main-sequence stars
RS Canum Venaticorum variables
K-type main-sequence stars
Binary stars
Eclipsing binaries
Ursa Major
Durchmusterung objects
237786
044998
Ursae Majoris, UX | XY Ursae Majoris | [
"Astronomy"
] | 523 | [
"Ursa Major",
"Constellations"
] |
70,253,847 | https://en.wikipedia.org/wiki/Beki%C4%87%27s%20theorem | In computability theory, Bekić's theorem or Bekić's lemma is a theorem about fixed-points which allows splitting a mutual recursion into recursions on one variable at a time. It was created by Austrian Hans Bekić (1936-1982) in 1969, and published posthumously in a book by Cliff Jones in 1984.
The theorem is set up as follows. Consider two operators and on pointed directed-complete partial orders and , continuous in each component. Then define the operator . This is monotone with respect to the product order (componentwise order). By the Kleene fixed-point theorem, it has a least fixed point , a pair in such that and .
Bekić's theorem (called the "bisection lemma" in his notes) is that the simultaneous least fixed point can be separated into a series of least fixed points on and , in particular:
In this presentation is defined in terms of . It can instead be defined in a symmetric presentation:
Proof (Bekić):
since it is the fixed point. Similarly . Hence is a fixed point of . Conversely, if there is a pre-fixed point with , then and ; hence and is the minimal fixed point.
Variants
In a complete lattice
A variant of the theorem strengthens the conditions on and to be that they are complete lattices, and finds the least fixed point using the Knaster–Tarski theorem. The requirement for continuity of and can then be weakened to only requiring them to be monotonic functions.
Categorical formulation
Bekić's lemma has been generalized to fix-points of endofunctors of categories (initial -algebras).
Given two functors and such that all and exist, the fix-point is carried by the pair:
Usage
Bekić's theorem can be applied repeatedly to find the least fixed point of a tuple in terms of least fixed points of single variables. Although the resulting expression might become rather complex, it can be easier to reason about fixed points of single variables when designing an automated theorem prover.
References
Order theory
Fixed-point theorems | Bekić's theorem | [
"Mathematics"
] | 428 | [
"Theorems in mathematical analysis",
"Order theory",
"Fixed-point theorems",
"Theorems in topology"
] |
70,257,076 | https://en.wikipedia.org/wiki/Thamnolic%20acid | Thamnolic acid is a β-orcinol depside with the molecular formula C19H16O11. Thamnolic acid was first isolated from the lichen Thamnolia vermicularis, but it also occur in Cladonia species.
References
Further reading
Lichen products
Polyphenols
Carboxylic acids
Methoxy compounds | Thamnolic acid | [
"Chemistry"
] | 77 | [
"Carboxylic acids",
"Natural products",
"Functional groups",
"Lichen products"
] |
70,257,270 | https://en.wikipedia.org/wiki/Yury%20Mikhailovich%20Bunkov | Yury (or Yuriy or Yuri) Mikhailovich Bunkov (Юрий Михайлович Буньков, 29 August 1950 in Stavropol) is a Russian experimental physicist, specializing in condensed matter physics. He is known as one of the co-discoverers of the quantum spin liquid state.
Education and career
Bunkov, born into a family of geologists, graduated in 1968 from a special school for physics and mathematics in Moscow (School No. 2). In 1968 he also achieved first place in the Moscow Physics Olympiad and matriculated at the Moscow Institute of Physics and Technology (MIPT), which was headed by Piotr Kapitza.
According to Bunkov, the "parametric echo" should be called the "Bunkov echo":
In 1974 he matriculated at the Kapitza Institute for Physical Problems, where he received in 1979 his Candidate of Sciences degree (Ph.D.). A. S. Borovik-Romanov was Bunkov's thesis advisor. At the Kapitza Institute for Physical Problems, he was employed as a non-principal scientist from 1979 to 1985, a principal scientist from 1985 to 1986, and from 1986 to 1995 as a leading scientist. At the Kapitza Institute he constructed the Soviet Union's first nuclear demagnetization refrigerator.
In 1983 at the Kapitza Institute, quantum spin superfluidity was discovered by Bunkov, who was the team leader, with Vladimir Dmitriev and Yuri Mukharsky (who worked at the Kapitza Institute as students). Spin superfluidity manifested itself in NMR studies on 3helium-B as regions of coherent Larmor precession (regions known as HPDs, Homogeneously Precessing Domains), with inhomogeneities in the precession caused by supercurrents in the spin (based on magnetization) similar to those in superconductivity (based on charge-supercurrent) and superliquid or Bose-Einstein condensates (based on mass-supercurrent). Spin superfluidity is also a Bose-Einstein condensate (BEC) of magnons. A theoretical explanation was given in the 1980s by the theorist Igor Akindinovich Fomin.
Bunkov wrote concerning his work at the Kapitza Institute:
At the Kapitza Institute, he received in 1985 his Russian Doctor of Sciences degree (habilitation) with a thesis on NMR studies on superfluid helium-3. At Grenoble's Institut Néel (formerly called CRTBT), belonging to the Centre National de la Recherche Scientifique (CNRS), he was employed from 1995 to 2004 as a Directeur de Recherche and since 2004 is employed as a Directeur de Recherche de 1er classe. From 2008 to the present, he is a part-time professor at Kazan Federal University.
For many years Bunkov participated in the Soviet-Finnish project ROTA, in which the researchers discovered many different types of 3He vortices. He also made many visits (from 1989 to 1995) to Lancaster University, where he participated in NMR experiments at record-setting low temperatures for 3He.
At CRTBT his research group cooled 3He to 100°K and, at such low temperatures, found in 1996 an energy deficit after a 3He neutron capture reaction. The energy deficit "appeared to arise from vortex creation via the Kibble-Zurek cosmological mechanism, in analogy with cosmic-string creation in the early Universe." He became the leader of the project ULTIMA (Ultra Low Temperature Instrumentation for Measurements in Astrophysics), which has as its purpose the development of a dark-matter detector based on overcooled superfluid 3He.
In the 3He-B phase (which has a complex phase structure) he experimentally discovered analogues to cosmological and quantum field theoretical phenomena, such as cosmological strings (as vortices in the spin supercurrent) and Majorana quasiparticles. In the 1980s he and his colleagues detected Goldstone modes (as phonons in the spin-superfluidity HPDs analogous to the second sound phenomena in superfluids). In the 2000s he discovered Q-balls] in superfluid 3He. (The concept of a Q-ball, a type of non-topological soliton, was originally introduced in quantum field theory.)
He collaborated extensively with the theorist Grigori Efimovich Volovik. In 2008, Bunkov and his Japanese colleagues discovered coherent precession in the helium-3-A phase embedded in uniaxially deformed anisotropic aerogels.
Bunkov is internationally recognized for his research on quantum fluids and solids, superfluid 3He nuclear magnetic resonance {NMR), and oltra-low temperatures techniques and their application to cosmology and the search for dark matter. As of the end of 2018 his Hirsch index was 26.
Bunkov received in 1993 the State Prize of the Russian Federation "for the discovery of magnetic superfluidity and the Homogeneously Precessing Domain". In 2001 Bunkov was made Doctor "Honoris Causa" by Pavol Jozef Šafárik University in Košice, Slovakia. In 2008 he was awarded, jointly with Vladimir Dmitriev and Igor A. Fomin, the Fritz London Memorial Prize for their discovery and elucidation of "unique phenomena in superfluid 3He-B: macroscopi phase-coherent spin precession and the flow of spin supercurrent." Bunkov has been a full member of the Academia Europaea since 2010.
Selected publications
with A.S. Borovik-Romanov, V.V. Dmitriev, Yu.M. Mukharskiĭ: Long-lived induction signal in superfluid in 3-He, JETP Lett., vol. 40, no. 6, 1984, pp. 1033–1037 (translated by Dave Parsons) pdf
with V.V. Dmitriev, Yu.M. Mukharskiy: Twist oscillations of homogeneous precession domain in 3He-B, JETP Lett., vol. 43, 1986, pp. 168–171. (Goldstone mode)
with A. S. Borovik-Romanov: Spin supercurrent and magnetic relaxation in Helium-3, Harwood Academic Publ. 1990.
with V.V.Dmitriev, Yu.M. Mukharskiy, Low frequency oscillations of the homogeneously precessing domain in 3He-B, Physica B, vol. 178, 1992, pp. 196–201. (Goldstone mode)
Persistent signal; coherent NMR state trapped by orbital texture, J. Low Temp. Phys., vol. 138, 2005, pp. 753–758, (Q-Ball)
with G.E. Volovik: Magnon condensation into a Q-ball in 3He-B, Phys. Rev. Lett., vol. 98, 2007, p. 265302.
Spin Supercurrent, J. of Magnetism and Magnetic Materials (2007 article published in 2018). Arxiv 2007
with T. Sato, T. Kunimatsu, K. Izumina, A. Matsubara, M. Kubota, T. Mizusaki: Coherent precession of magnetization in the superfluid 3He A-phase, Phys. Rev. Lett., vol. 101, 2008, p. 055301.
with G. E. Volovik: Bose-Einstein Condensation of Magnons in Superfluid 3He, J. Low Temperature Physics, vol. 150, 2008, pp. 135–144.
with G.E. Volovik: Magnon BEC in superfluid 3He-A, JETP Lett., vol. 89, 2009, pp. 306–310.
with G. E. Volovik: Magnon BEC and spin superfluidity: a 3He primer, Arxiv 2009
Spin superfluidity and magnons Bose-Einstein-Condensation, Physics Uspekhi, August 2010, Online
with G. E. Volovik: Spin superfluidity and magnon BEC, in: Int. Ser. Monogr. Phys. 156, 2013, pp. 253–311, Arxiv
with Rasul Gazizuzin: Observation of Majorana Quasiparticles Surface States in Superfluid 3He-B by Heat Capacity Measurements, Arxiv 2016
with Vladimir Safonov: Magnon Condensation and Spin Superfluidity, Arxiv 2017
with A. Farhutdinov. A. Kuzmichev, T. R. Safin, P. M. Vetoshko, V. I. Belotelov. and V. I. Tagirov: The magnonic superfluid droplet at room temperature. arXiv preprint arXiv:1911.03708 Arxiv 2019
Magnonic Superfluidity Versus Bose Condensation, Appl. Magn. Reson. vol. 51, 2020, pp. 1711–1721.
with A. N. Kuzmichev, T. R. Safin, P. M. Vetoshko, V. I. Belotelov, and M. S. Tagirov: Quantum paradigm of the foldover magnetic resonance, Scientific Reports, vol. 11, no. 1, 2021, pp. 1–8.
References
External links
Soviet physicists
20th-century Russian physicists
21st-century Russian physicists
Condensed matter physicists
Moscow Institute of Physics and Technology alumni
French National Centre for Scientific Research scientists
Academic staff of Kazan Federal University
Members of Academia Europaea
State Prize of the Russian Federation laureates
1950 births
Living people
People from Stavropol | Yury Mikhailovich Bunkov | [
"Physics",
"Materials_science"
] | 2,102 | [
"Condensed matter physicists",
"Condensed matter physics"
] |
70,257,442 | https://en.wikipedia.org/wiki/Erucin | Erucin (4-methylthiobutyl isothiocyanate) is a dietary isothiocyanate present in cruciferous vegetables that is considered a potential cancer chemopreventive nutraceutical.
Characteristics
Erucin is produced by the enzymatic hydrolysis of the glucosinolate glucoerucin present in Eruca sativa Mill. seeds (Brassicaceae or Cruciferae). Erucin has structural analogies with sulforaphane (SFN), an isothiocyanate derived from glucoraphanin, a glucosinolate present in some edible crucifers, and known in the literature for its chemopreventive properties. Different isothiocyanates exert anticancer properties on many tumor types (liver, breast, bladder, lung, and pancreatic), and in particular, SFN is employed in a pilot randomized controlled clinical trial in advanced pancreatic cancer.
References
Isothiocyanates
Cancer | Erucin | [
"Chemistry"
] | 216 | [
"Isothiocyanates",
"Functional groups"
] |
70,258,560 | https://en.wikipedia.org/wiki/Cairo%20Citadel%20Clock | The Cairo Citadel Clock is a 19th century French clock tower situated at the Cairo Citadel, and Egypt's first public ticking clock.
For many decades, the clock was famous for not working. Various attempts were made to fix the clock in the 20th century; a repair was ordered by King Farouk in 1943 and in 1984 under President Hosni Mubarak, but both times the clock stopped working a few days later. In November and December 2020, French Horologist Francois Simon-Fustier travelled to Cairo to examine the clock, and sent a report to the Egyptian Ministry of Tourism and Antiquities. The reparation of the clock was carried out by an Egyptian expert from Luxor. On 16 September 2021, the Egyptian Ministry of Tourism and Antiquities announced the completion of the restoration and restarting of the clock:
...the clock has been repaired by Egyptian craftsmen after years of nonoperation. The trials of the clock’s automatic winding [mechanism] have begun in order to ensure its continuous, uninterrupted operation. The restoration of the clock tower has been completed, and the colors have been enhanced to give it back its original luster. Maintenance and reinstallation of the stained glass panels and the rims of the circular iron columns located on the upper part of the column were also completed.
According to Osama Talaat, the clock had needed to be wound twice a day, but following the restoration now has a mechanism for "automatic winding of the clock without human assistance.”
The clock has been widely cited as having been sent by France in return for the Luxor obelisk now at the Place de la Concorde, however this has been disputed. Secretary General of the Supreme Council of Antiquities Mostafa Waziri said that the obelisk "… has nothing to do with the [clock] that [Louis Philippe] gave to Mohammad Ali. What proves this is that in 1845 the clock arrived to Mohammad Ali, and when it did, the construction of the Mohammad Ali Mosque in the citadel had not yet been completed, so the clock was placed in the Mohammad Ali Palace in Shubra. During the reign of Said Pasha, the tower was made until the clock was placed in the Mohammad Ali Mosque in 1855 AD."
Original placement
The clock was manufactured in France, and sent to Egypt in 1846 as a gift from the King Louis Philippe I of France to Muhammad Ali of Egypt. It was intended to be placed inside Muhammad Ali's Shubra Palace, but it was not installed and was left in the palace in storage.
Installation at the Citadel
The clock was installed at the Citadel in 1856 under Abbas I of Egypt, following the construction of the Mosque of Muhammad Ali which had been completed in 1848. The clock was housed inside a locally-made metal tower, which was decorated with Arabic inscriptions and stained glass.
Gallery
References
Clock towers in Egypt
Clocks
Buildings and structures in Cairo | Cairo Citadel Clock | [
"Physics",
"Technology",
"Engineering"
] | 590 | [
"Physical systems",
"Machines",
"Clocks",
"Measuring instruments"
] |
70,259,277 | https://en.wikipedia.org/wiki/Nonlinear%20tides | Nonlinear tides are generated by hydrodynamic distortions of tides. A tidal wave is said to be nonlinear when its shape deviates from a pure sinusoidal wave. In mathematical terms, the wave owes its nonlinearity due to the nonlinear advection and frictional terms in the governing equations. These become more important in shallow-water regions such as in estuaries. Nonlinear tides are studied in the fields of coastal morphodynamics, coastal engineering and physical oceanography. The nonlinearity of tides has important implications for the transport of sediment.
Framework
From a mathematical perspective, the nonlinearity of tides originates from the nonlinear terms present in the Navier-Stokes equations. In order to analyse tides, it is more practical to consider the depth-averaged shallow water equations:Here, and are the zonal () and meridional () flow velocity respectively, is the gravitational acceleration, is the density, and are the components of the bottom drag in the - and -direction respectively, is the average water depth and is the water surface elevation with respect to the mean water level. The former of the three equations is referred to as the continuity equation while the others represent the momentum balance in the - and -direction respectively.
These equations follow from the assumptions that water is incompressible, that water does not cross the bottom or surface and that pressure variations above the surface are negligible. The latter allows the pressure gradient terms in the standard Navier-Stokes equations to be replaced by gradients in . Furthermore, the coriolis and molecular mixing terms are omitted in the equations above since they are relatively small at the temporal and spatial scale of tides in shallow waters.
For didactic purposes, the remainder of this article only considers a one-dimensional flow with a propagating tidal wave in the positive -direction.This implies that zero and is all quatities are homogeneous in the -direction. Therefore, all terms equal zero and the latter of the above equations is arbitrary.
Nonlinear contributions
In this one dimensional case, the nonlinear tides are induced by three nonlinear terms. That is, the divergence term , the advection term , and the frictional term . The latter is nonlinear in two ways. Firstly, because is (nearly) quadratic in . Secondly, because of in the denominator. The effect of the advection and divergence term, and the frictional term are analysed separately. Additionally, nonlinear effects of basin topography, such as intertidal area and flow curvature can induce specific kinds of nonlinearity. Furthermore, mean flow, e.g. by river discharge, may alter the effects of tidal deformation processes.
Harmonic analysis
A tidal wave can often be described as a sum of harmonic waves. The principal tide (1st harmonic) refers to the wave which is induced by a tidal force, for example the diurnal or semi-diurnal tide. The latter is often referred to as the tide and will be used throughout the remainder of this article as the principal tide. The higher harmonics in a tidal signal are generated by nonlinear effects. Thus, harmonic analysis is used as a tool to understand the effect the nonlinear deformation. One could say that the deformation dissipates energy from the principal tide to its higher harmonics. For the sake of consistency, higher harmonics having a frequency that is an even or odd multiple of the principle tide may be referred to as the even or odd higher harmonics respectively.
Divergence and advection
In order to understand the nonlinearity induced by the divergence term, one could consider the propagation speed of a shallow water wave. Neglecting friction, the wave speed is given as:
Comparing low water (LW) to high water (HW) levels (), the through (LW) of a shallow water wave travels slower than the crest (HW). As a result, the crest "catches up" with the trough and a tidal wave becomes asymmetric.
In order to understand the nonlinearity induced by the advection term, one could consider the amplitude of the tidal current. Neglecting friction, the tidal current amplitude is given as:
When the tidal range is not small compared to the water depth, i.e. is significant, the flow velocity is not negligible with respect to . Thus, wave propagation speed at the crest is while at the trough, the wave speed is . Similar to the deformation induced by the divergence term, this results in a crest "catching up" with the trough such that the tidal wave becomes asymmetric.
For both the nonlinear divergence and advection term, the deformation is asymmetric. This implies that even higher harmonics are generated, which are asymmetric around the node of the principal tide.
Mathematical analysis
The linearized shallow water equations are based on the assumption that the amplitude of the sea level variations are much smaller than the overall depth. This assumption does not necessarily hold in shallow water regions. When neglecting the friction, the nonlinear one-dimensional shallow water equations read:Here is the undisturbed water depth, which is assumed to be constant. These equations contain three nonlinear terms, of which two originate from the mass flux in the continuity equation (denoted with subscript ), and one originates from advection incorporated in the momentum equation (denoted with subscript ). To analyze this set of nonlinear partial differential equations, the governing equations can be transformed in a nondimensional form. This is done based on the assumption that and are described by a propagating water wave, with a water level amplitude , a radian frequency and a wavenumber . Based on this, the following transformation principles are applied:The non-dimensional variables, denoted by the tildes, are multiplied with an appropriate length, time or velocity scale of the dimensional variable. Plugging in the non-dimensional variables, the governing equations read:The nondimensionalization shows that the nonlinear terms are very small if the average water depth is much larger than the water level variations, i.e. is small. In the case that , a linear perturbation analysis can be used to further analyze this set of equations. This analysis assumes small perturbations around a mean state of :Here .
When inserting this linear series in the nondimensional governing equations, the zero-order terms are governed by:This is a linear wave equation with a simple solution of form:
Collecting the terms and dividing by yields:
Three nonlinear terms remain. However, the nonlinear terms only involve terms of , for which the solutions are known. Hence these can be worked out. Subsequently, taking the -derivative of the upper and subtracting the -derivative of the lower equation yields a single wave equation:
This linear inhomogenous partial differential equation, obeys the following particulate solution:
Returning to the dimensional solution for the sea surface elevation:
This solution is valid for a first order perturbation. The nonlinear terms are responsible for creating a higher harmonic signal with double the frequency of the principal tide. Furthermore, the higher harmonic term scales with , and . Hence, the shape of the wave will deviate more and more from its original shape when propagating in the -direction, for a relatively large tidal range and for shorter wavelengths. When considering a common principal tide, the nonlinear terms in the equation lead to the generation of the harmonic. When considering higher-order terms, one would also find higher harmonics.
Friction
The frictional term in the shallow water equations, is nonlinear in both the velocity and water depth.
In order to understand the latter, one can infer from the term that the friction is strongest for lower water levels. Therefore, the crest "catches up" with the trough because it experiences less friction to slow it down. Similar to the nonlinearity induced by the divergence and advection term, this causes an asymmetrical tidal wave.
In order to understand the nonlinear effect of the velocity, one should consider that the bottom stress is often parametrized quadratically:Here is the drag coefficient, which is often assumed to be constant ().
Twice per tidal cycle, at peak flood and peak ebb, reaches a maximum, . However, the sign of is opposite for these two moments. Causally, the flow is altered symmetrical around the wave node. This leads to the conclusion that this nonlinearity results in odd higher harmonics, which are symmetric around the node of the principal tide.
Mathematical analysis
Nonlinearity in velocity
The parametrization of contains the product of the velocity vector with its magnitude. At a fixed location, a principal tide is considered with a flow velocity:
Here, is the flow velocity amplitude and is the angular frequency. To investigate the effect of bottom friction on the velocity, the friction parameterization can be developed into a Fourier series:
This shows that can be described as a Fourier series containing only odd multiples of the principal tide with frequency . Hence, the frictional force causes an energy dissipation of the principal tide towards higher harmonics. In the two dimensional case, also even harmonics are possible. The above equation for implies that the magnitude of the friction is proportional to the velocity amplitude . Meaning that stronger currents experience more friction and thus more tidal deformation. In shallow waters, higher currents are required to accommodate for sea surface elevation change, causing more energy dissipation to odd higher harmonics of the principal tide.
Nonlinearity in water depth
Although not very accurate, one can use a linear parameterization of the bottom stress:
Here is a friction factor which represents the first Fourier component of the more exact quadratical parameterization. Neglecting the advectional term and using the linear parameterization in the frictional term, the nondimensional governing equations read:Despite the linear parameterization of the bottom stress, the frictional term remains nonlinear. This is due to the time dependent water depth in its denominator. Similar to the analysis of the nonlinear advection term, a linear perturbation analysis can be used to analyse the frictional nonlinearity. The equations are given as:Taking the -derivative of the upper equation and subtracting the -derivative of the lower equation, the terms can be eliminated. Calling , this yield a single second order partial differential equation in :In order to solve this, boundary conditions are required. These can be formulated asThe boundary conditions are formulated based on a pure cosine wave entering a domain with length . The boundary () of this domain is impermeable to water. To solve the partial differential equation, a separation of variable method can be used. It is assumed that . A solution that obeys the partial differential equation and the boundary conditions, reads:Here, .
In a similar manner, the equations can be determined:Here the friction term was developed into a Taylor series, resulting in two friction terms, one of which is nonlinear. The nonlinear friction term contains a multiplication of two terms, which show wave-like behaviour. The real parts of and are given as:Here the denote a complex conjugate. Inserting these identities into the nonlinear friction term, this becomes:
The above equation suggests that the particulate solution of the first order terms obeys a particulate solution with a time-independent residual flow (quantities denoted with subscript ) and a higher harmonic with double the frequency of the principal tide, e.g. if the principal tide has a frequency, the double linearity in the friction will generate an component. The residual flow component represents Stokes drift. Friction causes higher flow velocities in the high water wave than in the low water, hence making the water parcels move in the direction of the wave propagation. When higher order terms in the perturbation analysis are considered, even higher harmonics will also be generated.
Intertidal area
In a shallow estuary, nonlinear terms play an important role and might cause tidal asymmetry. This can intuitively be understood when considering that if the water depth is smaller, the friction slows down the tidal wave more. For an estuary with small intertidal area (case i), the average water depth generally increases during the rising tide. Therefore, the crest of the tidal wave experiences less friction to slow it down and it catches up with the trough. This causes tidal asymmetry with a relatively fast rising tide. For an estuary with much intertidal area (case ii), the water depth in the main channel also increases during the rising tide. However, because of the intertidal area, the width averaged water depth generally deceases. Therefore, the trough of the tidal wave experiences relatively little friction slowing it down and it catches up on the crest. This causes tidal asymmetry with a relatively slow rising tide. For a friction dominated estuary, the flood phase corresponds to the rising tide and the ebb phase corresponds to the falling tide. Therefore, case (i) and (ii) correspond to a flood and ebb dominated tide respectively.
In order to find a mathematical expression to find the type of asymmetry in an estuary, the wave speed should be considered. Following a non-linear perturbation analysis, the time-dependent wave speed for a convergent estuary is given as:
With the channel depth, the estuary width, and the right side just a decomposition of these quantities in their tidal averages (denote by the ) and their deviation from it. Using a first order Taylor expansion, this can be simplified to:
Here:
This parameter represents the tidal asymmetry. The discussed case (i), i.e. fast rising tide, corresponds to , while case (ii), i.e. slow rising tide, corresponds to . Nonlinear numerical simulations by Friedrichs and Aubrey reproduce a similar relationship for .
Flow curvature
Consider a tidal flow induced by a tidal force in the x-direction such as in the figure. Far away from the coast, the flow will be in the x-direction only. Since at the coast the water cannot flow cross-shore, the streamlines are parallel to the coast. Therefore, the flow curves around the coast. The centripetal force to accommodate for this change in the momentum budget is the pressure gradient perpendicular to a streamline. This is induced by a gradient in the sea level height. Analogues to the gravity force that keeps planets in their orbit, the gradient in sea level height for a streamline curvature with radius is given as:
For a convex coast, this corresponds to a decreasing water level height when approaching the coast. For a concave coast this is opposite, such that the sea level height increases when approaching the coast. This pattern is the same when the tide reverses the current. Therefore, one finds that the flow curvature lowers or raises the water level height twice per tidal cycle. Hence it adds a tidal constituent with a frequency twice that of the principal component. This higher harmonic is indicative of nonlinearity, but this is also observed by the quadratic term in the above expression.
Mean flow
A mean flow, e.g. a river flow, can alter the nonlinear effects. Considering a river inflow into an estuary, the river flow will cause a decrease of the flood flow velocities, while increasing the ebb flow velocities. Since the friction scales quadratically with the flow velocities, the increase in friction is larger for the ebb flow velocities than the decrease for the flood flow velocities. Hence, creating a higher harmonic with double the frequency of the principal tide. When the mean flow is larger than the amplitude of the tidal current, this would lead to no reversal of the flow direction. Thus, the generation of the odd higher harmonics by the nonlinearity in the friction would be reduced. Moreover, an increase in the mean flow discharge can cause an increase in the mean water depth and therefore reduce the relative importance of nonlinear deformation.
Example: Severn Estuary
The Severn Estuary is relatively shallow and its tidal range is relatively large. Therefore, nonlinear tidal deformation is notable in this estuary. Using GESLA data of the water level height at the measuring station near Avonmouth, the presence of nonlinear tides can be confirmed. Using a simple harmonic fitting algorithm with a moving time window of 25 hours, the water level amplitude of different tidal constituents can be found. For 2011, this has been done for the , and constituents. In the figure, the water level amplitude of the and harmonics, and respectively, are plotted against the water level amplitude of the principal tide, . It can be observed that higher harmonics, being generated by nonlinearity, are significant with respect to the principal tide.
The correlation between and looks somewhat quadratic. This quadratic dependence could be expected from the mathematical analysis in this article. Firstly, the analysis of divergence and advection results in an expression that, for a fixed , implies:
Secondly, the analysis of the nonlinearity of the friction in the water depth yields a second higher harmonic. For the mathematical analysis, a linear parameterization of the bottom stress was assumed. However, the bottom stress actually scales nearly quadratically with the flow velocity. This is reflected in the quadratic relation between and .
In the graph, for a small tidal range, the correlation between and is approximately directly proportional. This relation between the principal tide and its third harmonic follows from the nonlinearity of the friction in the velocity, which is reflected in the derived expression. For larger tidal ranges, start decreasing. This behaviour remains unresolved by the theory covered in this article.
Sediment transport
The deformation of tides can be of significant importance in sediment transport. In order to analyse this, it is obvious to distinguish between the dynamics of suspended sediment and bed load sediment. Suspended sediment transport (in one dimension) can in general be quantified as:
Here is the depth integrated sediment flux, is the sediment concentration, is the horizontal diffusivity coefficient and is the reference height above the surface . The bed load transport can be estimated by the following heuristic definition:
Here is an erosion coefficient.
The zonal flow velocity can be represented as a truncated Fourier series. When considering a tidal flow composed of only and constituents, the current at a specific location is given as:A description of the local evolution of the suspended sediment concentration is required to obtain an expression for the tidally averaged suspended sediment flux. The local change of the depth integrated suspended sediment concentration () is governed by:
Here is the fall velocity, is the vertical diffusivity coefficient and is an erosion coefficient. Advection is neglected in this model. Considering the definition of and , an expression for the tidally averaged bed and suspended load transport can be obtained:Here , the ratio of the settling time scale over the tidal time scale. Two important mechanisms can be identified using the definitions of and . These two transport mechanisms are discussed shortly.
Velocity asymmetry
The velocity asymmetry mechanism relies on a difference in maximum flow velocity between peak ebb and flood. The quantification of this mechanism is encapsulated by the term. The implications of this term are summarized in the table below:
Hence, the velocity asymmetry mechanism causes a net ebb directed transport if the absolute value of the relative phase difference, while it causes a net flood directed transport if . In the latter case, peak flood flows will be larger than peak ebb flows. Hence, the sediment will be transported over a larger distance in the flood direction, making and . The opposite applies for .
Duration asymmetry
The duration asymmetry mechanism can also cause a tidally averaged suspended load transport. This mechanism only allows for a tidally averaged suspended sediment flux. The quantification of this mechanism is encapsulated by the term, which is absent in the equation. The implications of this term are summarized in the table below:
When , the time from peak flood to peak ebb is longer than the time from peak ebb to peak flood. This makes that more sediment can settle during the period from peak flood to peak ebb, hence less sediment will be suspended at peak ebb and there will be a net transport in the flood direction. A similar, but opposite explanation holds for . Bed load transport is not affected by this mechanism because the mechanism requires a settling lag of the particles, i.e. the particles must take time to settle and the concentration adapts gradually to the flow velocities.
See also
Tidal resonance
Tidal bore
Wave nonlinearity
Tides in marginal seas
Sediment transport
References
Tides
Physical oceanography | Nonlinear tides | [
"Physics"
] | 4,174 | [
"Applied and interdisciplinary physics",
"Physical oceanography"
] |
59,477,453 | https://en.wikipedia.org/wiki/Liliana%20Quintanar%20Vera | Liliana Quintanar Vera (born 1975) is a Mexican chemist. She works on proteins and neurodegenerative diseases.
Early life and education
Quintanar Vera was born in Mexico City in 1975. She took part in the Mexican Academy of Sciences Chemistry Olympics, representing the country in the International Chemistry Olympiad in 1993. She studied chemistry at National Autonomous University of Mexico in 1998. She was awarded the Gabino Barreda medal. She took part in an exchange program with the University of California, Santa Barbara. She worked on Neurochemistry with Stanley Parsons. Quintanar Vera joined Stanford University for her PhD, working on metalloproteins under the supervision of Edward I. Solomon. She focussed on the structure, function and activation mechanism of multicopper oxidase.
Career
Quintanar Vera returned to Mexico and join the National Autonomous University of Mexico Department of Neurochemistry of the Institute of Physiology. She worked on manganese neurotoxicity. She joined CINVESTAV in 2005, where she studies the proteins associated with neurodegenerative diseases. Alzheimer's disease can cause proteins to aggregate and accumulate metals. She studies the role of metals in the aggregation of proteins and the etiology of diseases.
Quintanar Vera was a Fulbright scholar at Massachusetts Institute of Technology working with Jonathan King between 2014 and 2015. Her project looked at the role of copper ions in human Gamma-D crystallin. Quintanar Vera was appointed to the Society International Biological Inorganic Chemistry in 2017. In 2017 she coordinated the Thematic Network of Structure, Function and Evolution of Proteins (REFEP).
Awards and honours
2017 Mexican Academy of Sciences Research Prize for Science
2016 Marcos Moshinsky Chair
2014 Fulbright Scholarship
2007 L'Oréal-UNESCO For Women in Science Awards
References
Living people
1975 births
Mexican women chemists
Women biochemists
National Autonomous University of Mexico alumni
Academic staff of the National Autonomous University of Mexico
Mexican women scientists
Mexican women academics
Mexican scientists | Liliana Quintanar Vera | [
"Chemistry"
] | 401 | [
"Biochemists",
"Women biochemists"
] |
59,477,820 | https://en.wikipedia.org/wiki/Oxidative%20carbonylation | Oxidative carbonylation is a class of reactions that use carbon monoxide in combination with an oxidant to generate esters and carbonate esters. These transformations utilize transition metal complexes as homogeneous catalysts. Many of these reactions employ palladium catalysts. Mechanistically, these reactions resemble the Wacker process.
Illustrative oxidative carbonylations
Oxidative carbonylation, using palladium-based catalysts, allows certain alkenes to be converted into homologated esters:
2 RCH=CH2 + 2 CO + O2 + 2 MeOH → 2 RCH=CHCO2Me + 2 H2O
Such reactions are assumed to proceed by the insertion of the alkene into the Pd(II)-CO2Me bond of a metallacarboxylic ester followed by beta-hydride elimination (Me = CH3).
Arylboronic acids react with Pd(II) compounds to give Pd(II)-aryl species, which undergo carbonylation to give Pd(II)-C(O)aryl. These benzyl-Pd intermediates are intercepted by alkenes, which insert. Subsequent beta-hydride elimination gives the arylketone.
The conversion of methanol to dimethylcarbonate by oxidative carbonylation is economically competitive with phosgenation. This reaction is practiced commercially using Cu(I) catalysts:
2 CO + O2 + 4 MeOH → 2 (MeO)2CO + 2 H2O
The preparation of dimethyl oxalate by oxidative carbonylation has also attracted commercial interest. It requires only C1 precursors:
4 CO + O2 + 4 MeOH → 2 (MeO2C)2 + 2 H2O
References
Chemical reactions
Carbon monoxide | Oxidative carbonylation | [
"Chemistry"
] | 384 | [
"nan"
] |
59,478,233 | https://en.wikipedia.org/wiki/Perpendicular%20paramagnetic%20bond | A perpendicular paramagnetic bond is a type of chemical bond that does not exist under normal, atmospheric conditions. Such a phenomenon was first hypothesized through simulation to exist in the atmospheres of white dwarf stars whose magnetic fields, on the order of 105 teslas, could allow such interactions to exist. In a very strong magnetic field, excited electrons in molecules may be stabilized, causing these molecules to abandon their original orientations parallel to the magnetic field and instead lie perpendicular to it. Normally, at such intense temperatures as those near a white dwarf, more common molecular bonds cannot form and existing ones decompose.
References
Astrophysics
Chemical bonding
White dwarfs
Hypothetical processes
Exotic matter
Magnetism in astronomy | Perpendicular paramagnetic bond | [
"Physics",
"Chemistry",
"Materials_science",
"Astronomy"
] | 143 | [
"Astronomical sub-disciplines",
"Astronomy stubs",
"Astrophysics",
"Hypotheses in chemistry",
"Astrophysics stubs",
"Condensed matter physics",
"nan",
"Exotic matter",
"Magnetism in astronomy",
"Chemical bonding",
"Matter"
] |
59,479,042 | https://en.wikipedia.org/wiki/NGC%205982 | NGC 5982 is an elliptical galaxy located in the constellation Draco. It is located at a distance of circa 130 million light years from Earth, which, given its apparent dimensions, means that NGC 5982 is about 100,000 light years across. It was discovered by William Herschel on May 25, 1788.
NGC 5982 has a kinematically decoupled nucleus, with its major axis being nearly perpendicular to the rotation of the galaxy. NGC 5982 features many shells in its envelope, nearly 26. The shells form circular arcs, with the further being located at a radius of 150 arcseconds along the major axis of the galaxy, while the innermost one lies 8 arcseconds off the nucleus. The shells and the kinematically decoupled nucleus are the result of the merger of the elliptical galaxy with a small elliptical galaxy.
The galaxy has globular clusters that belong in two populations, red and blue. The age of the globular clusters in NGC 5982 is over 5 billion years. The luminosity of NGC 5982 is dominated by light emitted by old stars. In the centre of NGC 5982 lies a supermassive black hole whose mass is estimated to be (108.92 ) based on the M–sigma relation. The nucleus may display low level activity and has been categorised as a possible LINER.
NGC 5982 belongs to a galaxy group known as the NGC 5982 group. Other members of the group include the galaxies NGC 5976, NGC 5981, NGC 5985, NGC 5987, and NGC 5989. NGC 5981, a spiral galaxy seen edge-on, lies at a separation of 6.3 arcminutes from NGC 5982 and NGC 5985, a spiral galaxy seen face-on, lies at a separation of 7.7 arcminutes. The three galaxies are known as the Draco Trio or the Draco Group, although there is no evidence that they form a compact group.
References
External links
NGC 5982 on SIMBAD
Elliptical galaxies
Shell galaxies
Draco (constellation)
5982
09961
55674
Astronomical objects discovered in 1788
Discoveries by William Herschel | NGC 5982 | [
"Astronomy"
] | 461 | [
"Constellations",
"Draco (constellation)"
] |
59,480,919 | https://en.wikipedia.org/wiki/C01-A042 | C01-A042 is a Novichok agent.
See also
Novichok agent
C01-A035
C01-A039
References
External links
Novichok agents
Acetylcholinesterase inhibitors
Organofluorides
Oxime esters
Phosphorofluoridates
Nitro compounds
Ethyl esters | C01-A042 | [
"Chemistry"
] | 71 | [
"Phosphorofluoridates",
"Functional groups"
] |
59,480,957 | https://en.wikipedia.org/wiki/Black%20Mirror%3A%20Bandersnatch | Black Mirror: Bandersnatch is a 2018 interactive film in the science fiction anthology series Black Mirror. It was written by series creator Charlie Brooker and directed by David Slade. The film premiered on Netflix on 28 December 2018, its release date only officially announced the day before. Netflix did not confirm the interactive nature of Bandersnatch until its release, though there was much media speculation.
In Bandersnatch, viewers make decisions for the main character, the young programmer Stefan Butler (Fionn Whitehead), who is adapting a fantasy gamebook into a video game in 1984. Other characters include Mohan Thakur (Asim Chaudhry) and Colin Ritman (Will Poulter), who work at a video game company; Stefan's father, Peter (Craig Parkinson); and Stefan's therapist, Dr. Haynes (Alice Lowe). A postmodernist work with free will as a central theme, the film was named after a real video game planned for release by Imagine Software in 1984, the game in turn named after the bandersnatch, a creature of Lewis Carroll's creation.
Brooker and executive producer Annabel Jones were approached by Netflix about making an interactive film in May 2017, during which time Netflix had several such projects for children underway. Difficulty in writing the highly non-linear script led to Netflix's creation of a bespoke program called Branch Manager; the unique nature of the content required adaptations in the platform's use of cache memory. Bandersnatch was originally to be part of Black Mirrors fifth series, but its lengthy production led to its release as a standalone film, delaying the fifth series to June 2019.
Critics praised the technical design of the film but criticised the story's characterisation. There was mixed commentary about the narrative and the extent to which viewer choices affected the story. The film received average rankings in critics' lists of Black Mirror instalments by quality, but garnered numerous awards and nominations, winning two Primetime Emmy Awards. A lawsuit filed by Chooseco over the film's use of the term "choose-your-own-adventure" was filed in January 2019 and settled in November 2020.
Synopsis
Format
Bandersnatch is an interactive film. A brief tutorial, specific to the device being streamed on, explains to the viewer how to make choices. When presented with a choice point, the user has ten seconds to make a choice or a default decision is made for them. The average viewing is 90 minutes, though the quickest path ends after 40 minutes. There are 150 minutes of unique footage divided into 250 segments, yielding over one trillion possible paths that the viewer can take. In some cases, the same scene is reachable in multiple different ways but will present the viewer with different choices based on the way they reached it. In other cases, certain loops guide viewers to a specific narrative regardless of the choices they make.
Netflix reported that there are five "main" endings, with variants within each ending; some endings are intercut with credits, similar to other Black Mirror episodes. Producer Russell McLean said there are between ten and twelve endings, some of which are more concrete than others, and according to director David Slade, there are a few "golden eggs" endings that are difficult to achieve. No ending is considered "prescribed" over any other, according to series creator Charlie Brooker and executive producer Annabel Jones, particularly as they felt some endings were not truly endings in the traditional sense. In most cases, when the viewer reaches an ending, the interactive film gives the player the option to redo a last critical choice in order to explore different content, sometimes with a fast-forward through early parts of a storyline already seen. Some endings may become impossible to reach based on choices made by the viewer unless they opt to restart the film.
Plot
In Britain in July 1984, a young programmer named Stefan Butler is adapting a "choose your own adventure" book owned by his late mother, Bandersnatch by Jerome F. Davies, into a revolutionary adventure game. Stefan pitches it to the video game company Tuckersoft, which is run by Mohan Thakur and employs the famous game creator Colin Ritman. Stefan is given the choice of accepting or rejecting help from the company in developing the game. If Stefan accepts, Colin says he chose the "wrong path". The game is released months later and critically panned as "designed by committee". Stefan considers trying again, and the film returns to the day of the offer, and the viewer is given the same choice.
Rejecting the offer, Stefan begins to work on the game on his own from his bedroom, given a September deadline. As the game becomes more complex, Stefan's life is torn between his career and his role, and he eventually becomes stressed and hostile to his father, Peter. He visits Dr. R. Haynes' clinic for therapy. The viewer may have Stefan explain to Dr. Haynes about his mother's death: when he was five, Peter confiscated his stuffed rabbit toy. His mother was delayed by Stefan's refusal to leave without the rabbit and the train she took derailed, killing her. Stefan feels responsible for her death. Dr. Haynes prescribes Stefan medicine, which the viewer can choose to have Stefan take or flush down the toilet.
The viewer may have Stefan accept an invitation to Colin's flat, where he lives with his girlfriend Kitty and infant daughter Pearl. The viewer is offered to take LSD with Colin or not, however in the latter case Colin then spikes Stefan's tea with the drug. Colin rants about secret government mind-control programs and alternate timelines. To demonstrate his theories, Colin demands Stefan choose one of them to jump off the balcony. If Stefan jumps, he dies and the game is finished by Tuckersoft to poor reviews. If Colin jumps, the whole encounter is revealed to be a dream, but Colin is absent in future scenes and remembers the event in that dream.
As the deadline to deliver the game looms, Stefan begins to feel he is being controlled by outside forces. Stefan finds his life mirroring that of Davies, about whom he learns through a book and a documentary that Colin gives him. Like Davies, he sees recurring imagery of a "branching pathway" symbol, which seemingly led to Davies beheading his own wife. As he begins to mentally break down, the viewer has multiple options to explain to Stefan who has been controlling him, including the option for Stefan to be told that he is being watched on Netflix in the 21st century. The viewer may discover a locked safe that contains either Stefan's old toy rabbit or documents about him being monitored as part of an experiment.
There are numerous possible endings. Stefan may choose to confront his therapist, after which it may be revealed that he is on a film set and that his "dad" is a fellow actor. One set of choices leads to Stefan seemingly crossing through a mirror to his five-year-old self, and then choosing whether to "die" with his mother in the train crash, causing him to suddenly die in the present. In other paths, the viewer has the option to make Stefan kill his father, and then bury or chop up the body. Burying it leads to Stefan being jailed before the release of the game. Dismembering it leads to the successful release of the game, but Stefan goes to prison shortly after, and the game is recalled and destroyed. Other scenes show Mohan, Colin, or Kitty arriving at Stefan's house, sometimes with the option to kill the characters. In some endings, the viewer is shown the critical reaction to the Bandersnatch game and the fate of Tuckersoft, which may go out of business. One ending (chop up the body) concludes in the present day with an adult Pearl, now a programmer for Netflix, attempting to adapt Bandersnatch into an interactive film. The viewer chooses for her to pour tea over her computer or destroy it, which implies she may go down the same path Davies and Stefan did.
Cast
Credits adapted from Screen Rant.
Production
Bandersnatch was released on Netflix on 28 December 2018 in 28 languages. It was originally intended to be an episode of series five, its scope changing to a standalone movie due to its complexity. Bandersnatch was made after one of the series five episodes was filmed. Brooker compared the effort spent on Bandersnatch to that of four regular Black Mirror episodes. As a consequence, the fifth season of Black Mirror was delayed, its three episodes premiering on 5 June 2019.
Conception and writing
The film was written by Charlie Brooker. He and Annabel Jones were approached by Netflix in May 2017 about making an interactive episode; their initial instinct was to reject the offer, particularly over concerns about the lack of seamless transitions from earlier interactive films. However, by the time of a script meeting a few weeks later to review potential ideas for the upcoming fifth series of Black Mirror, they had an idea for a plot that only worked as an interactive film. In it, a programmer would make a video game out of a choose-your-own-adventure book. Brooker had previously conceived of multiple endings for the third series episode "Playtest": a "nightmare mode" version of the episode, played when the viewer had seen the episode once before, would have ended with a much darker resolution.
Brooker initially envisaged the film as having one clear story, with a few different scenes at the end, until he had the idea of remembering earlier choices and incorporating them into later scenes. To keep the narrative focused with the numerous divergent endings, Brooker kept the story's core concept around the freedom of choice or the illusion of that freedom. Jones worked to develop believable characters that would fit with any of the film's possible endings. Discussions were had over the number of choices the viewer should make and how the film should be paced. The storylines and branches continued expanding into pre-production.
The flash-forward ending involving Pearl Ritman was expected to be the one most commonly reached. Brooker remarked that he found himself in a similar position as Pearl in trying to work himself through pages of complex decision trees while writing the script. Several of the paths lead the viewer towards the choice of having Butler kill his father, though the viewer can avoid this. However, not all endings can be reached without Butler killing his father. McLean stated that this was done to give the viewer the sense of having their own control over the narrative. Endings in which a reviewer gives a star rating to Bandersnatch were designed to encourage users to go back, though there is no way that, simultaneously, the game can get a good review and Stefan can have a happy ending.
Technical design
Brooker found a steep learning curve in the technology required to write the film's script. At Netflix's suggestion, Brooker wrote the 170-page script in Twine, a tool for writing interactive fiction, also using Scrivener, Final Draft and multiple versions of Microsoft Notepad. The basic structure of the film took the most time to write, and the script underwent seven different versions. As the first Netflix interactive content for adults, Bandersnatch required more complex choices than previous interactive works, leading Netflix staff to create a bespoke tool which they named Branch Manager. It only became available to Brooker a few months into the episode's development.
Brooker and the production considered how to present the choices to the player, initially considering GIF animation loops of the possible actions. Their initial designs confused test viewers, and they instead used text options, temporarily letterboxing the frame to make the choices clear. The lighting, sound design and aspect ratio of the film change while this takes place, designed to make the viewer feel pressure.
Streaming with seamless transitions from one scene to either of two choices requires the two subsequent scenes to be pre-cached, which meant that Bandersnatch could not be made available on some older devices, or Chromecast or Apple TV. To help viewers who may not be familiar with how adventure games work, the film includes an early, seemingly trivial choice of which breakfast cereal Stefan has. This not only shows the viewer how choices are presented during the film, but how their state is recalled by the Netflix app later in their viewing. In this case, the cereal selection informs a television advert in-movie. If no choices are selected, the film progresses by choices determined by Brooker to give the most basic version of the story.
Casting and filming
Bandersnatch was directed by David Slade, who previously directed series four episode "Metalhead". It starred Fionn Whitehead, Will Poulter, and Asim Chaudhry. Whitehead was only informed of the film's interactive nature after being offered the part. Davies was played by independent game developer Jeff Minter at Jones' suggestion, having previously appeared in a documentary made by Jones and Brooker. Some of Ritman's character was informed by Minter's own background. Writer Warren Ellis was also asked to portray Davies but could not commit to the open shooting schedule and travel that the show required.
Production took eight months, Netflix requiring assets to be locked in by the end of November 2018. The actors had two weeks to prepare, while filming lasted around 35 days, which was considerably longer than the average for a Black Mirror piece. Exterior filming took place at the shopping centre St George's Walk in Croydon, London, in April 2018. A flowchart was initially used on set but actors found it overcomplicated the situation. Whitehead and Poulter both compared the experience to theatre acting. Slade highlighted Colin as the hardest character to understand, as one scene needed to be shot three times, with Colin having different levels of knowledge at each stage. Slade told Poulter to focus not on how his character knew information, but simply that his character did know. Whitehead found it difficult to maintain his character's constant anxiety and tension.
Soundtrack
The soundtrack was composed by Brian Reitzell, who worked on it by writing separate scores for each of the major storylines, then filling in music for the scenes not already covered. Reitzell had previously worked on music for some video games, but had not worked on modular music of the same complexity, where music was required to sync up with choice point transitions. He aimed for the music to be tonally connected but not feel static or reused. Much of the musical equipment he used was from the 1980s, including video game sound chips and modified consoles. Music was required for the choice points, video games, flashbacks and recap fast-forwards within the film. Reitzell worked with Slade to make the soundtrack feel atmospheric. The film also uses many songs from the 1980s, including "Relax" by Frankie Goes to Hollywood, "O Superman" by Laurie Anderson and "Too Shy" by Kajagoogoo. The viewer has some choice over music played, including a decision between "Hold Me Now" by the Thompson Twins and "Here Comes the Rain Again" by the Eurythmics.
Unused content
Some ideas for the film went unused. At one point, trophies for unlocking scenes were considered, similar to Xbox achievements. Instead of a documentary on Jerome F Davies, it was conceived that Stefan could choose to watch an entire film with which viewers could interact. At a different point, Brooker wanted Stefan's father's blood to splatter across the viewer's cereal choice. A segment where the viewer enters the therapist's phone number was initially designed as a more difficult riddle, the codes "999" and "911" leading to alternate scenes of Stefan calling the police in the UK and US, respectively. Originally, Netflix meta-endings could only be unlocked after the first playthrough.
Whitehead reports that much more footage was shot than was used in the final version. The film features some scenes which viewers cannot access, as a result of late editing changes, including scenes being reordered. This is similar to video games, which often have unused content still stored in their files. One such scene was a third encounter between Stefan and Colin at the offices, in which Colin would start finishing Stefan's sentences; Brooker saw that at least one person had obtained the footage and shared it. Some material was cut from Bandersnatch, such as Stefan killing Colin with a knife, as the work was deemed to be violent enough already. Additionally cut was a scene from the same choice point which showed Stefan dropping the knife and embracing Colin.
Marketing and release
On 27 December 2018, Netflix released a 90-second trailer for Bandersnatch, establishing that the film would premiere the following day, on 28 December. On 3 January 2019, Netflix released two "featurettes" which look behind the scenes at the film.
There was much media speculation prior to the film's announcement, spurred by news that Black Mirror had been renewed for a fifth series by March 2018. Early reports in April 2018, including by Digital Spy and on social media, said that filming for Black Mirror was occurring in Croydon, asserting it was for an episode titled Bandersnatch. Around the start of December 2018, it was widely reported that Twitter users had spotted a since-deleted tweet from an official Netflix account, with a list of premiere dates including 28 December for Black Mirror: Bandersnatch. The film was certified by the Korean and Dutch ratings board prior to its release, the former reporting that it was 5 hours and 12 minutes in length. On 19 December 2018, Netflix added the title Black Mirror: Bandersnatch as an upcoming film, with the tagline "Be right back", in reference to the earlier episode of the same name. Various runtimes including 2 minutes, 36 minutes and 90 minutes were listed in different territories. In late December, media reported on an image of the cast and a claim that Slade would direct the episode.
The interactive nature of Bandersnatch was first publicly mentioned by Bloomberg News in October 2018, which cited an unnamed source that Netflix was developing an interactive episode of Black Mirror alongside several other interactive specials for release in 2018. A Netflix spokesperson, when asked by The Verge, responded with: "Thanks for reaching out! You have the ability to choose your own response from Netflix: this or this." The first "this" contained a link to a GIF from Unbreakable Kimmy Schmidt of a character saying "razzmatazz", and the second linking to a YouTube video of crickets chirping. No screeners were sent to critics in advance of the film's release, though Netflix invited select media writers to their headquarters about a month prior to release and gave them an opportunity to try the interactive film.
Only upon the film's release on 28 December did Netflix publicly confirm its interactive nature. Carla Engelbrecht, Netflix's director of product innovation, told The Hollywood Reporter that they did not officially announce that Bandersnatch would be an interactive episode so that viewers would not have "preconceived notions", such as an overestimation of the level of interactivity. Due to unpleasant comments following the release of Bandersnatch, Poulter announced that he would reduce his Twitter activity for mental health reasons. In a November 2021 interview with GQ, Poulter stated that he deleted his Twitter account in January 2019 after being harassed by keyboard warriors who mocked his appearance as Ritman. Poulter returned to Twitter in 2021, but he now uses it for platform causes that he supports like The Black Curriculum and Alzheimer's Research UK.
A week following the film's premiere, Netflix sent out a hint on its social media pages directing users on how to discover an obscure scene. A week later, Netflix tweeted pieces of data about viewer choices in the episode. For instance, 73% of viewers chose for Stefan to initially accept the job at Tuckersoft and of what Netflix deemed to be the five endings, the least viewed was the one where Stefan boards the train with his mother as a child. Later, Netflix reported that 94% of viewers were actively making choices.
Following the release of Bandersnatch to Netflix, a live website for the fictional company Tuckersoft was made available. The site documented some of the fictional games discussed in the film and included a playable version of Nohzdyve that required the use of a ZX Spectrum computer or an emulator. The film was also advertised after its release on the London Underground. Within a week of its release, a number of mock "Tucker's Newsagent and Games" storefronts appeared in London and Birmingham, styled as a 1980s store with the various Tuckersoft games, and VHS tapes of other Black Mirror episodes.
Netflix and interactive fiction
Netflix had previously released interactive programmes for children, starting in 2017 with Puss in Book. Netflix also released the 2015 Telltale Games interactive series Minecraft: Story Mode on their website in November 2018. Bandersnatch was their first release targeted at adults. Netflix went on to produce additional shows using the Branch Manager tool. Bear Grylls' eight-episode interactive reality series You vs. Wild, fashioned after Man vs. Wild, was released in April 2019. An interactive special for the comedy Unbreakable Kimmy Schmidt was released in May 2020.
The Verge Jesse Damiani commented that interactivity as in Bandersnatch could potentially be used by Netflix to collect user-preference data and inform marketing choices, such as targeted product placement. In February, technology policy researcher Michael Veale requested the data that Netflix stored about his viewings of Bandersnatch under the General Data Protection Regulation. He criticised that the data, detailing every choice he had made, was not anonymised and was taken without explicit consent from the user. A 2019 paper by researchers at the Indian Institute of Technology Madras demonstrated how to infer viewers' choices in Bandersnatch through network packet analysis with 96% accuracy. The paper noted that this could be used to reveal viewer preferences "from benign (e.g., their food and music preferences) to sensitive (e.g., their affinity to violence and political inclination)", and noted a technical solution Netflix could implement.
As Netflix moved into more traditional gaming markets in the early 2020s, the company’s development and output of interactive programmes slowed, with then-vice president of Netflix Games Mike Verdu stating in an interview in December 2023 that “the technology was very limiting and the potential for what we could do in that realm was kind of capped” and said that Netflix were “not building those specific experiences anymore”. Netflix later announced on November 4, 2024 that they would be removing most of their interactive programmes from the service the following month, though Bandersnatch would be one of the four interactive programmes that remained on the service. Game designer Sam Barlow, who had developed video games with full-motion video previously, said that Bandersnatch only worked as its story worked at a metafiction level with the nature of interactive works, a formula that couldn't easily be replicated in Netflix' future works.
Lawsuit
Chooseco, the company founded by R. A. Montgomery to republish the Choose Your Own Adventure book series, filed a lawsuit against Netflix for trademark infringement by use of the phrase "choose your own adventure" in Bandersnatch, seeking upwards of in damages. Chooseco claimed it trademarked the phrase in association with movies, books, and other forms of media, and that Netflix started negotiations with Chooseco in 2016 to license the phrase for films and animated series, which did not pan out. Netflix sought to have the suit summarily dismissed on a number of grounds related to trademark law and fair use allowances, but this was denied by the presiding judge based on evidence brought by Chooseco, the full case scheduled to proceed by February 2020. Netflix continued to seek dismissal, arguing that the "choose your own adventure" term had fallen into a generic trademark, and that the branch of the story where it shows Stefan being controlled by a person watching Netflix makes the work different from past "Choose Your Own Adventure" books which put the reader into the role of the protagonist. By November 2020, Netflix had conceded and offered to settle the case with Chooseco on undisclosed terms.
Analysis
A 1980s period piece and a work of science fiction, Bandersnatch also contains elements of comedy, horror and pathos. It has been described as a psychological thriller. The film heavily incorporates ideas of postmodernism, containing meta-commentary and an unreliable narrator, with free will as a central theme. Ed Cumming of The Independent commented that it contains themes of "authorial control, free will and fate". Beth Elderkin of io9 wrote that Bandersnatch is about the absence of choice, and Stefan's life being outside of his control. Elderkin highlighted the "White Rabbit" ending, in which Stefan finds his rabbit under his bed as a child and joins his mother in dying on the train, as the one point where "free will is celebrated instead of derided". These ideas and themes of monitoring and control, as well as the 1984 setting, led to comparisons to George Orwell's novel Nineteen Eighty-Four. Stuart Heritage of The Guardian wrote that "Brooker has popularised a new form of storytelling, then identified its tropes and dismantled them one by one."
The work was compared to a wide variety of media. Keith Spencer of Salon made comparisons to early internet-era hypertext fiction and the previous Netflix interactive work Puss in Book, which has a broadly similar plot of a character being driven mad by the knowledge that they are controlled by an external force. David Griffin of IGN compared it to the adventure video game series The Walking Dead, whose first installment was released in 2012, and the 2018 adventure game Detroit: Become Human. Karl Quinn of The Sydney Morning Herald compared the work to Mosaic, a 2017 murder mystery released by HBO as an interactive app. Brooker also compared the story to the 1993 comedy fantasy Groundhog Day, about a character who re-lives the same day repeatedly.
The term "bandersnatch" originates from a fictional creature created by Lewis Carroll, which appears in his 1870s poems "Jabberwocky" and "The Hunting of the Snark". The former appears in the novel Through the Looking-Glass, the sequel to Alice's Adventures in Wonderland. A planned video game by Imagine Software, Bandersnatch, took its name from the creature. Its name was mentioned in an Easter egg in series three episode "Playtest", on the front cover of a magazine which is briefly shown onscreen. One of several expensive "megagames" which Imagine Software worked on, Bandersnatch was never released as the company went bankrupt in 1984. Imagine's closure was widely publicised because of the BBC's "Commercial Breaks" series which followed the company's closure and its cascading effects on the British video game industry. As an allusion, the film opens on 9 July 1984, the day Imagine Software closed.
The story shares elements of the works of Philip K. Dick, who frequently wrote about alternate realities and timelines. Jerome F. Davies—the archetype of a tortured artist—can be seen as an allusion to Dick, who frequently used recreational drugs throughout his life, and at one point attempted to kill his wife. The original book cover of Dick's Ubik is prominently featured in Colin's apartment. Rosie Knight of The Hollywood Reporter compared Davies to writer William S. Burroughs, who killed his second wife. In Bandersnatch, there is no ending in which Stefan is happy and the game gets a good review. Jackson McHenry of Vulture wrote that this implied "a link between mental illness, violence, and creativity". Brooker responded that the game itself could be "a force of evil" and said that "the less friction there is in Stefan's life, the more boring the story for an onlooker becomes".
Easter eggs
Like previous instalments of Black Mirror, Bandersnatch makes allusions to earlier episodes. The "branching path" symbol which Davies and later Butler experience is a motif from the series two episode "White Bear". One of Tuckersoft's games is Metl Hedd, a reference to "Metalhead", while Ritman is shown to be working on a game called Nohzdyve, referencing the episode "Nosedive". Butler attends counselling at the Saint Juniper clinic, named after "San Junipero". References to a wide range of events associated with other Black Mirror episodes can be seen in news stories shown in brief shots of the pages of The Sun newspaper and on a television news crawl. The character Dr. R. Haynes alludes to Rolo Haynes, the proprietor of the titular showcase in "Black Museum". There are also Easter eggs to series five episodes which were yet to be released, such as the mention of "Smithereens" character Billy Bauer in a news ticker.
Brooker, Slade and McLean discussed whether there was deeper meaning in the Easter eggs. Slade was reluctant to include the Metl Hedd game, not finding "the need for it". Slade commented that Tuckersoft could later have become TCKR, a company in "San Junipero" and thought that "Metalhead" was an event in the future rather than a simulation. McLean said that stories are developed in isolation, rather than by asking "how do we fit the story into this universe?" Brooker saw the Easter eggs as "a nice nod to superfans" which should not affect the creative process or force viewers to watch the stories in a particular order. Brooker and Poulter have suggested that the character of Colin Ritman could potentially show up in future Black Mirror stories, given that the character, in certain paths, seems to just disappear but has awareness of alternate timelines and realities.
In one ending, the sound of a computer data tape recording is heard; loading the sound into a ZX Spectrum generates a QR code with the White Bear glyph in the middle that leads to the fictional Tuckersoft website, where a playable copy of the ZX Spectrum game Nohzdyve can be downloaded. This ending was at one point intended to be a clue to a real life treasure hunt in which people could find Bandersnatch cassettes, inspired by the 1979 picture book Masquerade that gave hints as to the location of a buried bejewelled golden hare.
Reception
On Rotten Tomatoes, 74% of 72 reviews are positive for the film, with an average rating of 7.5/10. The website's critical consensus reads, "While Bandersnatch marks an innovative step forward for interactive content, its meta narrative can't quite sustain interest over multiple viewings — though it provides enough trademark Black Mirror tech horror to warrant at least one watch." According to Metacritic, the film received "generally favorable reviews" based on a weighted average score of 61 out of 100 from 16 critic reviews. It garnered ratings of four out of five stars in The Independent and The Observer, and three stars in Rolling Stone. IndieWire gave it an A− rating and IGN reviewed it as eight out of ten.
Describing the piece as "incredibly funny at times", Heritage reviewed it as a "masterpiece of sophistication". Liz Shannon Miller of IndieWire found it "hard-to-define" but "impossible to forget". Quinn believed it to be one of the better instalments of Black Mirror, saying that it was a "brilliant foray into a (more or less) new realm of visual storytelling". However, Brian Lowry of CNN wrote that it was "a wildly familiar plot for a psychological thriller" and Spencer said that the storyline "isn't particularly memorable". Austen Goslin of Polygon criticised that the narrative is "like a cleverly disguised straight line".
The technical design of Bandersnatch was widely praised. Griffin wrote that the tutorial "does a solid job of explaining how the experience works". The user interface and transitions between choice points were lauded by critics including Heritage and NPRs Linda Holmes, who both called it "seamless", and Griffin, who found the feature "smooth and unobtrusive". Miller commented that "the system was very smart about knowing when to essentially fast-forward through earlier storylines to move things forward". The relationship between interactivity and the storyline, however, received less positive reception. Griffin reviewed that the "short amount of time" to make a choice could cause frustration. Goslin believed that the interactivity leads to "staccato pacing that prevents anyone involved from finding a real rhythm in each scene", Roisin O'Connor of The Independent concurring that the choices "can become quite wearisome". Lowry said that the medium "winds up feeling like a gimmick".
The narrative received further criticism. Spencer found it "riddled with cliche", saying that Stefan questioning the nature of free will "has been done to death in print" and other interactive fiction. Holmes wrote that "it would have been good to see this technology demonstrated on a stronger story". Lowry found that the story kept "circling back", which was "numbing and repetitive". Holmes agreed, finding it "deeply frustrating" when she was "simply shown the same segment of story again" until she made the choice "that will actually move you forward". Lucy Mangan of The Observer experienced that the story "rarely landed in an unexpected place". Overall, Rolling Stones David Fear criticised that the experience gave "little to hold onto after the fact" and that "the story doesn't matter". Holmes found it "especially poorly suited to being watched more than once". In contrast, Cumming reviewed that the medium "is bound with the plot", which "saves the film from pure gimmickry". Griffin felt "responsible" for Stefan's behaviour and "more and more invested in his story". Miller and Quinn both praised the self-referential "Netflix" branch of the story.
The characters were met with mostly negative commentary. Goslin called them "paper thin and barely interesting"; Mangan wrote that the medium did not have "energy to spare to make the characters much more than ciphers". Holmes criticised that the "isolated artist" trope "doesn't really hold up a narrative on its own". She further said that the audience doesn't "learn enough about who [Stefan] is to care about him". In regard to Stefan's backstory involving his mother's death, Goslin commented that Bandersnatch is "really only interested in this premise as a bridge toward its ultimate destination: becoming meta commentary on itself and video games as a medium". However, the acting was met with praise from Griffin, who approved of "impactful performances from Fionn Whitehead and Will Poulter", and Cumming, finding that Poulter "steals most of his scenes". Cumming further wrote that "the dialogue is as knowing and smart as we have come to expect".
Episode rankings
Bandersnatch received mixed rankings on critics' lists of the 23 instalments of Black Mirror, from best to worst:
5th (of the Top Seven) – Al Horner, GQ
5th – Ed Power, The Telegraph
6th – Matt Donnelly and Tim Molloy, TheWrap
11th – Charles Bramesco, Vulture
11th – Travis Clark, Business Insider
13th – Morgan Jeffery, Digital Spy
14th – Corey Atad, Esquire
14th – James Hibberd, Entertainment Weekly
14th – Aubrey Page, Collider
Awards
Among its nominations, Bandersnatch won two Primetime Emmy Awards and a Broadcasting Press Guild TV and Radio Award in the Innovation category. Charlie Brooker won the Best Game Writing category at the 2018 Nebula Awards in 2019, rather than a storytelling category.
See also
Brataccas, a 1986 video game which may have been based on the 1984 vaporware game project Bandersnatch by Imagine Software
Interactive Adventures, a series of online interactive stories created by Chad, Matt & Rob that are a predecessor to the Bandersnatch storytelling model
Notes
References
External links
Tuckersoft, fictional company site
Black Mirror: Bandersnatch on Rotten Tomatoes
Black Mirror: Bandersnatch on Metacritic
2010s interactive fiction
2010s psychological horror films
2010s science fiction horror films
2018 films
Black Mirror episodes
English-language science fiction horror films
Netflix original films
Films about books
Films about computing
Films about nightmares
Films about video games
Films directed by David Slade
Films scored by Brian Reitzell
Films set in 1984
Films shot in London
Interactive films
Nebula Award for Best Game Writing–winning works
Postmodern works
Self-reflexive films
Television shows about suicide
Films about murder
Films about suicide
Films about grief
Films about drugs
Metaphysical fiction films
2010s English-language films
Primetime Emmy Award for Outstanding Made for Television Movie winners | Black Mirror: Bandersnatch | [
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59,482,685 | https://en.wikipedia.org/wiki/RU-56187 | RU-56187 is a nonsteroidal antiandrogen which was never marketed. It shows 92% of the affinity of testosterone for the androgen receptor and negligible affinity for other steroid hormone receptors. The medication is a silent antagonist of the androgen receptor. RU-56187 is 3- to 10-fold more potent as an antiandrogen than bicalutamide or nilutamide in animals. Both RU-56187 and RU-58841 appear to be prodrugs of cyanonilutamide (RU-56279) in vivo in animals.
See also
RU-57073
RU-58642
RU-59063
References
Abandoned drugs
Imidazolines
Ketones
Nitriles
Nonsteroidal antiandrogens
Organosulfur compounds
Prodrugs
Trifluoromethyl compounds | RU-56187 | [
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59,482,698 | https://en.wikipedia.org/wiki/The%20Space%20Barons | The Space Barons: Elon Musk, Jeff Bezos, and the Quest to Colonize the Cosmos is a 2018 book by Christian Davenport. It covers the rise of the commercial space companies Blue Origin, led by Amazon founder Jeff Bezos, and SpaceX, led by PayPal and Tesla Motors founder Elon Musk.
See also
Billionaire space race
References
2018 non-fiction books
Works about space programs
PublicAffairs books
SpaceX
Blue Origin
Works about Elon Musk
Jeff Bezos | The Space Barons | [
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59,483,081 | https://en.wikipedia.org/wiki/RU-57073 | RU-57073 is a nonsteroidal antiandrogen which was never marketed. It shows 163% of the affinity of testosterone for the androgen receptor and negligible affinity for other steroid hormone receptors.
See also
Cyanonilutamide
Nilutamide
RU-56187
RU-58642
RU-58841
RU-59063
References
Abandoned drugs
Primary alcohols
Ketones
Imidazolines
Nitriles
Nonsteroidal antiandrogens
Organosulfur compounds
Trifluoromethyl compounds | RU-57073 | [
"Chemistry"
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"Ketones",
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"Nitriles",
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59,483,303 | https://en.wikipedia.org/wiki/Cyanonilutamide | Cyanonilutamide (developmental code name RU-56279) is a nonsteroidal antiandrogen which was never marketed. Both RU-56187 and RU-58841 appear to be prodrugs of cyanonilutamide in vivo in animals. It has relatively low affinity for the androgen receptor but nonetheless shows significant antiandrogenic activity in animals.
See also
5N-Bicalutamide
Nilutamide
RU-56187
RU-58642
RU-59063
References
Abandoned drugs
Human drug metabolites
Imidazolines
Nitriles
Nonsteroidal antiandrogens
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"Abandoned drugs"
] |
59,484,195 | https://en.wikipedia.org/wiki/NGC%201380 | NGC 1380 is a lenticular galaxy located in the constellation Fornax. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 1380 is about 85,000 light years across. It was discovered by James Dunlop on September 2, 1826. It is a member of the Fornax Cluster.
Supermassive black hole and nucleus
In the centre of NGC 1380 lies a supermassive black hole whose mass is estimated to be based on the velocity dispersion of the globular clusters of the galaxy. The nucleus of NGC 1380 is a probable LINER, based on its narrow emission lines. No broad line region has been detected in NGC 1380. The nuclear spectrum appears reddened, maybe due to the presence of gas and dust around the nucleus, maybe a result of mergers. There appears to be a second element in the nucleus of the galaxy, maybe an HII region. NGC 1380 features a gas disk which co-rotates with the stellar disk, suggesting an internal origin. There is an HII region 1.8 arcseconds south of the nucleus and a diffuse H-alpha region, another HII region, observed 1.8 arcseconds north of the nucleus. The X-ray emission from the galaxy as observed by ROSAT can be explained as thermal emission from a hot interstellar medium and no hard component was detected.
Globular clusters
It is estimated that there are globular clusters in NGC 1380. There are two district populations of globular clusters, one red and one blue. The blue globular clusters have similar color and magnitude as the globular clusters in the halo of the Milky Way, but have a flatter surface density profile. The red globular clusters form the majority of the globular clusters of the galaxy. They have similar distribution to the stellar disk of NGC 1380 and have slightly higher metallicity than the globular clusters in the Milky Way, and are associated with the bulge of the galaxy. Based on their size, there are three star cluster populations, the typical globular clusters, with effective radius under 3 kpc, the diffuse star clusters, with effective radius circa 5 kpc, and the faint fuzzy clusters, with effective radius over 8 kpc. The typical globular clusters are closer to the nucleus than the diffuse star clusters.
Environment
NGC 1380 lies in the central part of the Fornax Cluster, 35 arcminutes northwest of the large elliptical galaxy NGC 1399. In the same field of view lie the galaxies NGC 1380A, NGC 1379, NGC 1381, NGC 1382, and NGC 1387. NGC 1380 lies 2 degrees north-northeast of χ2 Fornacis and because of its high surface brightness can be spotted with a five inch telescope even from bright suburban skies.
Based on the properties of its inner stellar halo, it appears that NGC 1380 went through a massive galaxy merger event about 10 billion years ago. The now-consumed satellite galaxy contributed to the mass of NGC 1380, which is about one-fifth of its current mass.
Supernova
One supernova has been detected in NGC 1380: SN 1992A (type Ia mag. 12.8) was discovered by W. Liller on 11 January 1992 and independently by N. Brown on 12 January 1992.
Gallery
See also
List of NGC objects (1001–2000)
References
External links
NGC 1380 on SIMBAD
Lenticular galaxies
Fornax
Fornax Cluster
1380
013318
Discoveries by James Dunlop
Astronomical objects discovered in 1826
-06-09-002
358- G 028
03345-3508 | NGC 1380 | [
"Astronomy"
] | 759 | [
"Fornax",
"Constellations"
] |
59,485,605 | https://en.wikipedia.org/wiki/Toxicovigilance | Toxicovigilance is the process of identifying and evaluating the risks of poisoning that exist within a community, and proposing and evaluating measures taken to reduce, eliminate or manage them. More specifically, the goal of toxicovigilance is to identify specific circumstances or agents giving rise to poisoning, or certain populations suffering a higher incidence of poisoning. This way, emerging toxicological issues can be revealed, such as the reformulation of a chemical product or a change to its packaging or labelling, the spread of a new illegal drug, or a hazardous environmental contamination. Once an issue has been identified, appropriate health and other authorities can be alerted so they can take the necessary preventive, repressive or regulatory measures.
The practice of toxicovigilance often involves the registration of cases of poisoning by health professionals, or the analysis of enquiries made to poison control centers. Because of this, practising toxicovigilance is often one of the core tasks of a poison control center.
There is an overlap between toxicovigilance and for example pharmacovigilance or environmental health. They are all are aspects of the broader concept of public health surveillance.
See also
Public health
Toxicology
References
Poison control centers
Toxicology
Medical monitoring | Toxicovigilance | [
"Environmental_science"
] | 255 | [
"Toxicology"
] |
59,488,563 | https://en.wikipedia.org/wiki/Monobutyl%20phthalate | Monobutyl phthalate (MBP) is an organic compound with the condensed structural formula CH3(CH2)3OOCC6H4COOH. It is a white solid that features both an butyl ester group and a carboxylic acid group. It is the major metabolite of dibutyl phthalate. Like many phthalates, MBP has attracted attention as a potential endocrine disruptor.
MBP is also the secondary metabolite of butyl benzyl phthalate, less than monobenzyl phthalate (MBzP). It hydrolyses to phthalic acid and 1-butanol.
References
Phthalate esters
Endocrine disruptors | Monobutyl phthalate | [
"Chemistry"
] | 156 | [
"Endocrine disruptors"
] |
59,488,746 | https://en.wikipedia.org/wiki/Successive%20interference%20cancellation | Successive Interference Cancellation (SIC) is a technique used by a receiver in a wireless data transmission that allows decoding of two or more packets that arrived simultaneously (in a regular system, more packets arriving at the same time cause a collision).
SIC is achieved by the receiver decoding the stronger signal first, subtracting it from the combined signal and then decoding the difference as the weaker signal.
References
Wireless
Wireless networking | Successive interference cancellation | [
"Technology",
"Engineering"
] | 86 | [
"Wireless",
"Wireless networking",
"Telecommunications engineering",
"Computer networks engineering"
] |
67,362,875 | https://en.wikipedia.org/wiki/Darling%2058 | The Darling 58 is a genetically engineered American chestnut tree. The tree was created by American Chestnut Research & Restoration Program at the State University of New York College of Environmental Science and Forestry (SUNY ESF) in collaboration with The American Chestnut Foundation (TACF) to restore the American chestnut to the forests of North America. These Darling-58 trees are attacked by chestnut blight, but survive. Darling-58 trees survive to reach maturity, produce chestnuts, and multiply to restore the American chestnut tree to the forests of North America. An error resulted in use of an alternate cultivar, Darling 54 in some field tests of the Darling 58 cultivar of American Chestnut.
While The American Chestnut Foundation discontinued support of development of the Darling 58 cultivar in December 2023, in part due to the mistaken use of Darling 54 in field trials, The American Chestnut Research & Restoration Program, who originated the tree, continues its development.
Background
The chestnut blight was introduced in the late 19th century with the Japanese chestnut and decimated the once-widespread American chestnut tree. Native un-modified trees are killed from the ground up by the blight, and only the root system survives. The roots then continue to send up shoots that are once again attacked by the blight and die back before they reach maturity, repeating the cycle.
Mechanism
Chestnut blight damages trees by producing oxalic acid, which lowers the pH in the cambium and kills plant tissues. Darling 58 adds a oxalate oxidase (OxO) gene from wheat, driven by a CaMV 35S promoter. The promoter allows the OxO protein to be made all through the plant. The OxO protein allows the plant to break down the acid before too much damage is done. The same defense strategy is found not only in wheat, but also in strawberries, bananas, oats, barley, and other cereals. The resistant trait is passed down to progeny. The resistance does not stop the blight from completing its lifecycle.
Extensive testing done with the transgenic Darling 58 variant to assess its effects on other species showed that the survival, pollen use, and reproduction of bumble bees were not affected by oxalate oxidase at the typical concentrations found in the pollen of the American chestnut. Presence of the transgenic oxalate oxidase gene in the genome of the American chestnut has little effect on photosynthetic or respiratory physiology.
History
In 2013, reported initial experiments to introduce wheat OxO into American chestnuts. Potted transgenic plants with two different promoters (35S, VspB) were created. OxO levels are measured out of the plant leaves. Infection experiments on cut leaves show that the lesion sizes can be reduced to around or below the level of the blight-resistant Chinese chestnut, suggesting that the potted plant may be resistant too.
In 2014, SUNY ESF reported that the "Darling4" transgenic event produced an intermediate level of resistance between American and Chinese chestnuts. The trait was also passed into progeny.
The Darling 58 (SX58) line was produced before 2016. A 2020 SUNY-ESF Masters thesis shows that Darling 58 is the transgenic event that produces the highest amount of OxO.
In January 2020, the researchers submitted a deregulation petition for the Darling 58 variant, with a public comment period ending October 19, 2020.
In November 2022, the USDA began another public comment period for Darling 58's approval.
In 2022, SUNY-ESF scientists reported that a different promoter, win3.12 from the eastern cottonwood, allows the expression levels of OxO to remain low in basal conditions, but increase under wound or infection. This modification is expected to be more metabolically efficient compared to the "always-on" CAMV promoter and thereby have greater transgene stability over successive generations compared with the Darling 58 variant. In laboratory bioassays, win3.12-OxO lines showed elevated disease tolerance similar to that exhibited by blight-resistant Chinese chestnut.
In December 2023, TACF announced that they were discontinuing development of the Darling 58 due to poor performance results. The SUNY ESF is continuing to seek federal approval to distribute seeds to the public without the support of TACF.
Darling 54
In December 2023, it was announced that there had been a mishap and any material known as "Darling 58" was actually "Darling 54". Darling 54 is a transgenic American chestnut tree also modified with the 35S:OxO construct. The difference between D58 and D54 is that D54 has the 35S:OxO construct inserted into a coding sequence within its genome. D58 was thought to have the 35S:OxO construct inserted into a non-coding region of the genome. An insertion in a coding sequence, or gene, could disrupt or alter gene expression and therefore protein function. The 35S:OxO construct is located within the Sal1 gene of the D54 genome. Sal1 is linked to drought stress and oxidative stress responses in other species.
References
Further reading
The USDA Should Let People Plant Blight-Resistant American Chestnut Trees
Castanea
Ecological restoration
Genetically modified organisms | Darling 58 | [
"Chemistry",
"Engineering",
"Biology"
] | 1,068 | [
"Genetic engineering",
"Ecological restoration",
"Genetically modified organisms",
"Environmental engineering"
] |
67,362,876 | https://en.wikipedia.org/wiki/Charles%20Driscoll | Charles Thurston Driscoll Jr. is a University Professor of Environmental Systems and distinguished Professor of Civil & Environmental Engineering in the College of Engineering and Computer Science at Syracuse University. He is known for his work on environmental chemistry, biogeochemistry, environmental engineering, aquatic chemistry, and water quality modeling.
Education
Driscoll earned his bachelor's degree in Civil Engineering at University of Maine in 1974. He earned his MS and PhD at Cornell University. His 1980 PhD thesis was titled "Chemical characterization of some dilute acidified lakes and streams in the Adirondack region of New York State".
Career
Driscoll began his career as professor in 1980 in the L.C. Smith College of Engineering and Computer Science at Syracuse University.
Awards
Driscoll was elected member of the National Academy of Engineering in 2007 for "For leadership in understanding the ecological impact of acid rain and mercury depositions".
In 2017, he was elected member of the American Association for the Advancement of Science for "his seminal contributions on the effect of acid rain and mercury deposition on aquatic and terrestrial communities, and for service to the international scientific community".
In 2023, Driscoll was awarded the Athalie Richardson Irvine Clarke Prize in water science by the National Water Research Institute.
References
External links
Official Website
Cornell University alumni
American environmental scientists
Fellows of the American Association for the Advancement of Science
Living people
Members of the United States National Academy of Engineering
Syracuse University faculty
Year of birth missing (living people)
University of Maine alumni | Charles Driscoll | [
"Environmental_science"
] | 307 | [
"American environmental scientists",
"Environmental scientists"
] |
67,362,944 | https://en.wikipedia.org/wiki/AC-42 | AC-42 is a selective, allosteric agonist of the M1 muscarinic acetylcholine receptor. AC-42 was the first selective M1 agonist to be discovered and its derivatives have been used to study the binding domain of the M1 receptor.
References
Benzaldehydes
M1 receptor agonists
Piperidines | AC-42 | [
"Chemistry"
] | 71 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
67,365,724 | https://en.wikipedia.org/wiki/Renwick%20Jajneswar%20%26%20Co%20Limited | Renwick Jajneswar & Co Limited () is a Bangladesh government owned company that manufactures machines and parts for sugar mills.
History
Renwick Jajneswar & Co Limited was established in 1881. It is located on a 37-acre site in Kushtia.
Renwick Jajneswar & Co Limited was delisted from the Dhaka Stock Exchange briefly after delays with converting paper shares into electronic shares.
Renwick Jajneswar & Co Limited had been operating in a deficit and by January 2019 it had been months since workers were paid at the company. It switched from buying scrap metals from state owned sugar mills to a private contractor, Azam & Sons, increasing the cost of raw materials. According to Dhaka Tribune there is a strong syndicate involved in embezzling funds from the company. The newspaper reported that the syndicate is controlled by accountants, Alamgir Hossain and Partha Pratim Saha, of the company.
The government of Bangladesh owns 51% of the shareholders while the rest are held by the general public. The public shareholders do not have a director on the Board of Directors representing their interests. BRB cables has bought 26.89% of the shares of the company from the stock market. According to Dhaka Stock Exchange 17.38% of the shares was owned by institutional investors and the remaining 31.62% by general shareholders. BRB cables hoped to place a director on the company board. It was the second state owned company, after Eastern Cables Limited, in which BRB cables bought significant number of shares.
Bangladesh Sugar and Food Industries Corporation, a state owned corporation, owned sugars mills owed half a billion taka to Renwick Jajneswar & Co Limited in November 2019. An audit report stated that the company was at risk of closure unless it could collect the debts from state owned sugar mills.
References
1881 establishments in India
Government-owned companies of Bangladesh
Organisations based in Kushtia District
Sugar industry of Bangladesh
Industrial machine manufacturers | Renwick Jajneswar & Co Limited | [
"Engineering"
] | 401 | [
"Industrial machine manufacturers",
"Industrial machinery"
] |
67,366,286 | https://en.wikipedia.org/wiki/Bromerguride | Bromerguride (), also known as 2-bromolisuride, is an antidopaminergic and serotonergic agent of the ergoline group which was described as having atypical antipsychotic properties but was never marketed. It was the first antidopaminergic ergoline derivative to be discovered. The pharmacodynamic actions of bromerguride are said to be "reversed" relative to its parent compound lisuride, a dopaminergic agent.
References
Abandoned drugs
Atypical antipsychotics
Bromoarenes
Dopamine antagonists
Ergolines
Serotonin receptor antagonists
Serotonin receptor agonists
Ureas | Bromerguride | [
"Chemistry"
] | 151 | [
"Organic compounds",
"Ureas",
"Drug safety",
"Abandoned drugs"
] |
67,366,324 | https://en.wikipedia.org/wiki/Australian%20Technical%20Advisory%20Group%20on%20Immunisation | The Australian Technical Advisory Group on Immunisation (ATAGI) is a technical advisory group of the Australian Government. As part of the Department of Health, ATAGI provides advice to the Minister of Health on the immunisation program of Australia and related matters, including the strength of evidence pertaining to existing, new, and emerging vaccines.
Roles
ATAGI's role
The main role of ATAGI is to provide advice on the administration of vaccinations related to the National Immunisation Program (NIP) to the Minister of Health
Advisory on the ongoing immunisation research or the most needed areas
furnish industry supports with pre-accommodation guidance for likely entries to the Pharmaceutical Benefits Advisory Committee (PBAC) on immunisation viability and use in Australia. ATAGI guidance should be looked for before support making an accommodation to the PBAC
Discussion with pertinent associations to create the Australian Immunisation Handbook
Discussion with significant associations in carrying out vaccination arrangements, strategies and immunization security
Members
ATAGI's members are appointed by Minister of Health (including a Chair and Deputy Chair) through an informal nomination process for a term of four years. ATAGI comprise voting members (including a Chair and Deputy Chair) and six ex-officio members, which are:
Assistant Secretary, Immunisation Branch, (Office for Health Protection) Department of Health
Director, Drug Safety and Evaluation, Therapeutic Goods Administration
Representative from the National Immunisation Committee
Representative from the Communicable Diseases Network Australia
Director of the National Centre for Immunisation Research and Surveillance
Voting Members
, ATAGI's voting member are as follows:
Temporary Members
Temporary members may be appointed on a short term basis to provide specific expertise on key topics. Temporary members will be voting members for the term of their appointment to ATAGI.
Meetings
The standard number of ATAGI meetings is six per year (in February, April, June, August, October and December), however they are yet to meet in 2024. These are pre-planned annually, according to the schedules of government and department programmes for the year. However, it is open for ATAGI to organise meetings and consultations at any time, whenever there may be need, on the group's initiative, or at the request of the department.
Recommendations
Advice during COVID-19 pandemic
On 8 April 2021 during the COVID-19 pandemic in Australia, ATAGI met with the Therapeutic Goods Administration (TGA) regarding the recent concerns of blood clots following administration of the Oxford–AstraZeneca COVID-19 vaccine. ATAGI advised the government to use the AstraZeneca vaccine only for people over the age of 50. However on 17 June 2021, after cases of thrombosis with thrombocytopenia syndrome (TTS) and two deaths, ATAGI changed their previous advice and only recommended the AstraZeneca vaccine for those over 60 years-of-age. The Commonwealth government followed their advice.
COVID-19 vaccines for 12 to 15 years old individuals
On 27 August 2021, Pfizer Comirnaty vaccine has been recommended by ATAGI for adolescents aged 12 years or older after the TGA had extended the registration of the vaccine for administration to those age groups on 23 July 2021.
Booster dose for severely immunocompromised
On 8 October 2021, ATAGI recommends the government start the rollout of booster dose (3rd dose) of COVID-19 vaccines for severely immunocompromised persons aged 12 years old or older. The preferable vaccines for booster dose are the mRNA vaccine (Pfizer or Moderna).
A 2 to 6 months interval for the booster dose from the date of second dose of the previous vaccine is recommended by ATAGI.
Booster dose for adult Australians
On 28 October 2021, ATAGI recommends the Comirnaty (Pfizer) vaccine as a booster dose for Australians aged 18 years or older, regardless of the previous COVID-19 vaccine used. The booster dose should be taken after six months from the second dose of the last course vaccination. However, the booster dose is not mandatory but recommended for high priority groups like aged care facilities, Aboriginal and Torres Strait Islanders, healthcare workers, people with underlying medical conditions, and people at increased occupational risk of COVID-19.
See also
Therapeutic Goods Administration
National Immunization Technical Advisory Group (the global concept)
Advisory Committee on Immunization Practices, immunisation advisory committee in the (United States)
Joint Committee on Vaccination and Immunisation, immunisation advisory committee in the (United Kingdom)
National Advisory Committee on Immunization, immunisation advisory committee in (Canada)
Standing Committee on Vaccination, immunisation advisory committee in Germany
References
Commonwealth Government agencies of Australia
Medical and health organisations based in Australia
National agencies for drug regulation
Regulation of medical devices
Life sciences industry
Regulatory authorities of Australia | Australian Technical Advisory Group on Immunisation | [
"Chemistry",
"Biology"
] | 998 | [
"Life sciences industry",
"National agencies for drug regulation",
"Drug safety"
] |
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