In toxicology, the median lethal dose, LD50, LC50 or LCt50 is a measure of the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of increased toxicity; the test was created by J. W. Trevan in 1927; the term semilethal dose is used in the same sense, in particular with translations of foreign language text, but can refer to a sublethal dose. LD50 is determined by tests on animals such as laboratory mice. In 2011, the U. S. Food and Drug Administration approved alternative methods to LD50 for testing the cosmetic drug Botox without animal tests; the LD50 is expressed as the mass of substance administered per unit mass of test subject as milligrams of substance per kilogram of body mass, sometimes stated as nanograms, micrograms, or grams per kilogram. Stating it this way allows the relative toxicity of different substances to be compared, normalizes for the variation in the size of the animals exposed.

For substances in the environment, such as poisonous vapors or substances in water that are toxic to fish, the concentration in the environment is used, giving a value of LC50. But in this case, the exposure time is important; the choice of 50% lethality as a benchmark avoids the potential for ambiguity of making measurements in the extremes and reduces the amount of testing required. However, this means that LD50 is not the lethal dose for all subjects. Measures such as "LD1" and "LD99" are used for specific purposes. Lethal dosage varies depending on the method of administration. For this reason, LD50 figures are qualified with the mode of administration, e.g. "LD50 i.v." The related quantities LD50/30 or LD50/60 are used to refer to a dose that without treatment will be lethal to 50% of the population within 30 or 60 days. These measures are used more within Radiation Health Physics, as survival beyond 60 days results in recovery. A comparable measurement is LCt50, which relates to lethal dosage from exposure, where C is concentration and t is time.

It is expressed in terms of mg-min/m3. ICt50 is the dose; these measures are used to indicate the comparative efficacy of chemical warfare agents, dosages are qualified by rates of breathing for inhalation, or degree of clothing for skin penetration. The concept of Ct was first proposed by Fritz Haber and is sometimes referred to as Haber's Law, which assumes that exposure to 1 minute of 100 mg/m3 is equivalent to 10 minutes of 10 mg/m3; some chemicals, such as hydrogen cyanide, are detoxified by the human body, do not follow Haber's Law. So, in these cases, the lethal concentration may be given as LC50 and qualified by a duration of exposure; the Material Safety Data Sheets for toxic substances use this form of the term if the substance does follow Haber's Law. For disease-causing organisms, there is a measure known as the median infective dose and dosage; the median infective dose is the number of organisms received by a person or test animal qualified by the route of administration. Because of the difficulties in counting actual organisms in a dose, infective doses may be expressed in terms of biological assay, such as the number of LD50's to some test animal.

In biological warfare infective dosage is the number of infective doses per cubic metre of air times the number of minutes of exposure. As a measure of toxicity, LD50 is somewhat unreliable and results may vary between testing facilities due to factors such as the genetic characteristics of the sample population, animal species tested, environmental factors and mode of administration. There can be wide variability between species as well. For example, comparatively harmless to humans, is known to be toxic to many animals; when used to test venom from venomous creatures, such as snakes, LD50 results may be misleading due to the physiological differences between mice and humans. Many venomous snakes are specialized predators on mice, their venom may be adapted to incapacitate mice. While most mammals have a similar physiology, LD50 results may or may not have equal bearing upon every mammal species, such as humans, etc. Note: Comparing substances to each other by LD50 can be misleading in many cases due to differences in effective dose.

Therefore, it is more useful to compare such substances by therapeutic index, the ratio of LD50 to ED50. The following examples are listed in reference to LD50 values, in descending order, accompanied by LC50 values, when appropriate. Animal-rights and animal-welfare groups, such as Animal Rights International, have campaigned against LD50 testing on anim

This is a list of the federal institutions of Brazil: National Congress, Congresso NacionalChamber of Deputies, Câmara dos Deputados Senate of Brazil, Senado FederalCourt of Audit of the Union, Tribunal de Contas da União Cabinet of Brazil, Gabinete Ministerial National Defense Council, Conselho de Defesa Nacional Cabinet of Institutional Security, Gabinete de Segurança Institucional Chief of Staff, Casa Civil da Presidência da República National Antidrugs Secretariat, Secretaria Nacional Antidrogas Special Secretariat for Human Rights, Secretaria Especial dos Direitos Humanos General-Secretariat of the Presidency, Secretaria-Geral da Presidência Attorney General of the Union, Advocacia-Geral da União Press Secretary, Secretaria de Comunicação Social Spokesman of the Presidency, Porta-Voz da Presidência Strategic Affairs Unit, Núcleo de Assuntos Estratégicos Instituto Nacional de Colonização e Reforma Agrária Secretaria de Produção e Comercializão Secretaria de Defesa Agropecuária National Institute of Meteorology, Instituto Nacional de Meteorologia Brazilian Agency of Telecommunications, Agência Nacional de Telecomunicações Brazilian Post and Telegraph Corporation, Empresa Brasileira de Correios e Telégrafos Institute of National Historical and Artistic Heritage, Instituto do Patrimônio Histórico e Artístico Nacional National Cinema Agency, Agência Nacional do Cinema House of Rui Barbosa Foundation, Fundação Casa de Rui Barbosa Palmares Cultural Foundation, Fundação Cultural Palmares National Foundation of Arts, Fundação Nacional de Artes National Library Foundation, Fundação Biblioteca Nacional National Museum of Brazil, Museu Nacional Brazilian Army, Exército Brasileiro Brazilian Air Force, Força Aérea Brasileira Aeronautical Accidents Investigation and Prevention Center, Centro de Investigação e Prevenção de Acidentes Aeronáuticos Brazilian Navy, Marinha do Brasil Linked entitiesBrazilian Airport Infrastructure Company, Empresa Brasileira de Infraestrutura Aeroportuária Higher War School, Escola Superior de Guerra Armed Forces Hospital, Hospital das Forças Armadas National Civil Aviation Agency, Agência Nacional de Aviação Civil National Institute of Metrology and Industrial Quality Instituto Nacional de Metrologia, Normalização e Qualidade Industrial, National Institute of Industrial Property Instituto Nacional da Propriedade Industrial National Bank for Economic and Social Development Banco Nacional de Desenvolvimento Econômico e Social National Institute of Educational Studies and Investigations, Instituto Nacional de Estudos e Pesquisas Educacionais National Council of Education, Conselho Nacional da Educação Joaquim Nabuco Foundation, Fundação Joaquim Nabuco Federal Centers of Technological Education, Centros Federais de Educação Tecnológica Federal agrotechnical schools, Escolas agrotécnicas federais Federal universities Councils and commissions Conselho Nacional do Meio Ambiente Conselho Nacional da Amazônia Legal Conselho Nacional de Recursos Hídricos Conselho Deliberativo do Fundo Nacional do Meio Ambiente Conselho de Gestão do Patrimônio Genético Comissão de Gestão de Florestas Públicas Comissão Nacional de Florestas Serviço Florestal Brasileiro Linked entities Agência Nacional de Águas Brazilian Institute of Environment and Renewable Natural Resources, Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis Instituto Chico Mendes de Conservação da Biodiversidade Instituto de Pesquisas Jardim Botânico do Rio de Janeiro Companhia de Desenvolvimento de Barcarena Rio Branco Institute, Instituto Rio Branco Alexandre de Gusmão Foundation, Fundação Alexandre de Gusmão Secretariats Secretaria-ExecutivaSubsecretaria de Planejamento Orçamento e AdministraçãoSecretaria de Acompanhamento Econômico Secretaria de Assuntos Internacionais Secretaria de Política Econômica Secretariat of Federal Revenue of Brazil, Secretaria da Receita Federal do Brasil Secretariat of National Treasury, Secretaria do Tesouro NacionalCollegiate Organs Conselho Monetário Nacional Conselho Nacional de Política Fazendária Conselho de Recursos do Sistema Financeiro Nacional Conselho Nacional de Seguros Privados Conselho de Recursos do Sistema Nacional de Seguros Privados, de Previdência Privada Aberta e de Capitalização Council for Financial Activities Control, Conselho de Controle de Atividades Financeiras Câmara Superior de Recursos Fiscais Conselhos de Contribuintes Comitê Brasileiro de Nomenclatura Comitê de Avaliação de Créditos ao Exterior Comitê de Coordenação Gerencial das Instituições Financeiras Públicas FederaisLinked entities Autarchies:Central Bank of Brazil, Banco Central do Brasil Comissão de Valores Mobiliários Superintendência de Seguros PrivadosPublic companies:Casa da Moeda do Brasil Serviço Federal de Processamento de Dados Caixa Econômica Federal Empresa Gestora de AtivosMixed economy companies:Banco do Brasil Brasil Resseguros Banco da Amazônia Banco do Nordeste do Brasil Banco do Estado do Piaui Banco do Estado de Santa Catarina BESC Crédito Imobiliário State Secretariat for Human Rights, Secretaria de Estado dos Direitos Humanos National Secretariat of Justice, Secretaria Nacional de Justiça National Prison Department, Departamento Penitenciário Nacional Department of Foreigners, Departamento de Estrangeiros National Secretariat of Public Security, Secretaria Nacional de Segurança Pública Secretariat for Economic Rights, Secretaria de Direito Econômico Department of Consumer Protection and Defence, Departamento de Proteção e Defesa do Consumidor Department of Economic Pro

Nick Woodward is a former NASCAR driver. He was a part-time fixture in the sport from 2001-2003. Woodward still races on the short tracks of the Eastern coast. Woodward debuted in 2001. After qualifying 24th, Woodward stayed on the lead lap and ended up 11th place, just outside the top-10, he earned another top-20 finish the next outing at South Boston. After starting 13th, Woodward finished that race 19th. Woodward returned to the Long team in 2003. Once again, Woodward was solid. After started 23rd, Woodward found himself in the 14th position by the end of the day. Woodward competed in two events in 2002 both for Jay Robinson Racing. In his debut, which came at Dover, Woodward qualified his way into the field with a 37th place lap. Despite having a wheel bearing let go, Woodward did gaining valuable experience. Woodward did end up finishing the race at Milwaukee, but did not improve on his Dover effort as he finished 31st. Nick Woodward driver statistics at Racing-Reference

The Manécanterie is an ancient monument situated in Lyon in Saint Jean district, in the 5th arrondissement of Lyon. It is placed side by side to the south southwest of the cathedral Saint Jean and is a part of the former convent of the cathedral; this small Romanesque building served first as dining hall to the canons of Saint Jean, before becoming a parish choir school, namely a school for the singing of the clergy. The Parish choir school is the oldest building of Lyon, with the exception of the Roman buildings, it was built in the 11th century, in a style mixing the Gothic and Romanesque influences, but it is based on constructions of the 2nd and 8th centuries. It was successively transformed throughout the late Middle Ages and the modern time because the roadway of the Place Saint Jean was raised twice; the Parish choir school, the sculptures of the saints, underwent damages by the troops of François de Beaumont, baron des Adrets, during the siege of Lyon in 1562 by the Protestants. From the 16th to the 18th century, the building had many architectural modifications, including the drilling of Gothic windows, the addition of a floor above the frieze, the transformation of the ground floor into shops, the filling of certain arches.

In the 18th century, the building became a parish choir school, during the French Revolution, it became the national property. In 1862, it was classified as monument historique; the current facade has a blind arcade overlaid with foliage, carried by small columns on pilasters. There are red bricks arranged in a geometrical way between the above. From 1930, the building became the place of deposit a place of exhibition as museum, the Trésor de la Cathédrale de Saint-Jean, established during the 19th century by the cardinals Joseph Fesch and Louis Jacques Maurice de Bonald and, composed of liturgical objects such as old books, jewelry and tapestry. Media related to Manécanterie de Lyon at Wikimedia Commons

Mariano Antonio Guadalupe Escobedo de la Peña was a Mexican Army general and former Governor of Nuevo León. Mariano Escobedo was born in San Pablo de los Labradores, Nuevo León on January 16, 1826, he was the youngest of six children born to Rita de la Peña. In 1854 he defended from the liberal rows the Plan de Ayutla that would end the dictatorship of Antonio López de Santa Anna, he took part in the Battle of Puebla on May 5 of 1862, in Puebla, where thanks to his bravery, was promoted to colonel of cavalry. He was promoted to general and organized an Army Corps which fought against the French invading troops, defeating them and capturing emperor Maximilian I in Querétaro. During the presidency of Benito Juárez Mariano Escobedo was named commander-in-chief of the northern zone and after the restoration of the Mexican republic, he was governor of several states and military secretary in 1875, in addition to being president of the Supreme Court of Military Justice. With the arrival of General Porfirio Diaz to the presidency, he was exiled to the United States, from which he organized an uprising against the dictator.

Because of that he was taken prisoner. He died in Mexico, on May 22, 1902. General Mariano Escobedo International Airport

The ATA-214 class was a group of five auxiliary tugs built for the United States Navy in World War II and decommissioned shortly thereafter. They were laid down as Ailanthus-class net laying ships, but on 10 July 1944 the last ten ships of the latter class were cancelled. On 5 August 1944 the cancellation was rescinded for those on which construction had commenced, they were directed to be completed as tugs; the assigned names were dropped, they were identified only by hull numbers ATA-214 through 218. Some changes were made. After the first two were completed the mainmast was moved forward to rest directly behind the funnel, the boom on this mast was eliminated as unnecessary. Armament varied as well, based upon experiences with the Ailanthus class vessels built; the first two completed had a single 3" gun mounted on a platform ahead of the bridge, three 20mm antiaircraft guns mounted in two tiers in front of the funnel. It was found that the upper of these three was too close to the funnel, for the next two this mount was relocated behind the mainmast.

For the last ship the 3" gun was eliminated and two 40mm AA guns were mounted on the forecastle. All five served in the Pacific theater, ATA-215, ATA-216, ATA-218 participated in the occupation of Japan in various periods from September to November 1945. ATA-215 was sold upon its return.