Problem: Normal functioning of the kidney, brain, liver, heart, and other systems can be affected by uranium exposure, because, besides being weakly radioactive, uranium is a toxic metal. Uranium is also a reproductive toxicant. Radiological effects are generally local because alpha radiation, the primary form of 238U decay, has a very short range, and will not penetrate skin. Uranyl (UO2+
2) ions, such as from uranium trioxide or uranyl nitrate and other hexavalent uranium compounds, have been shown to cause birth defects and immune system damage in laboratory animals. While the CDC has published one study that no human cancer has been seen as a result of exposure to natural or depleted uranium, exposure to uranium and its decay products, especially radon, are widely known and significant health threats. Exposure to strontium-90, iodine-131, and other fission products is unrelated to uranium exposure, but may result from medical procedures or exposure to spent reactor fuel or fallout from nuclear weapons. Although accidental inhalation exposure to a high concentration of uranium hexafluoride has resulted in human fatalities, those deaths were associated with the generation of highly toxic hydrofluoric acid and uranyl fluoride rather than with uranium itself. Finely divided uranium metal presents a fire hazard because uranium is pyrophoric; small grains will ignite spontaneously in air at room temperature.
At what temperature will grains of plutonium metal spontaneously ignite in air?
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Answer: unanswerable


Problem: The club's success in the late 1990s and first decade of the 21st century owed a great deal to the 1996 appointment of Arsène Wenger as manager. Wenger brought new tactics, a new training regime and several foreign players who complemented the existing English talent. Arsenal won a second League and Cup double in 1997–98 and a third in 2001–02. In addition, the club reached the final of the 1999–2000 UEFA Cup (losing on penalties to Galatasaray), were victorious in the 2003 and 2005 FA Cups, and won the Premier League in 2003–04 without losing a single match, an achievement which earned the side the nickname "The Invincibles". The feat came within a run of 49 league matches unbeaten from 7 May 2003 to 24 October 2004, a national record.
What caused Arsenal's loss to Galatasarey in the 1999-2000 season?
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Answer: penalties


Problem: In 1821, Mexico won its independence from Spain, and San Diego became part of the Mexican territory of Alta California. In 1822, Mexico began attempting to extend its authority over the coastal territory of Alta California. The fort on Presidio Hill was gradually abandoned, while the town of San Diego grew up on the level land below Presidio Hill. The Mission was secularized by the Mexican government in 1833, and most of the Mission lands were sold to wealthy Californio settlers. The 432 residents of the town petitioned the governor to form a pueblo, and Juan María Osuna was elected the first alcalde ("municipal magistrate"), defeating Pío Pico in the vote. (See, List of pre-statehood mayors of San Diego.) However, San Diego had been losing population throughout the 1830s and in 1838 the town lost its pueblo status because its size dropped to an estimated 100 to 150 residents. Beyond town Mexican land grants expanded the number of California ranchos that modestly added to the local economy.
Who was in the running for the last alcalde position, but was defeated in the election?
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Answer:
unanswerable