Input: Read this: In 2014, the FAA changed a long-standing approach to air traffic control candidates that eliminated preferences based on training and experience at flight schools in favor of a personality test open to anyone irrespective of experience. The move was made to increase flight traffic controller racial diversity. Before the change, candidates who had completed coursework at participating colleges and universities could be "fast-tracked" for consideration. The agency eliminated that program and instead switched to an open system to the general public, with no need for any experience or even a college degree. Instead, applicants could take "a biographical questionnaire" that many applicants found baffling.
Question: When did the agency switch to a system where people could be "fast-tracked" for consideration?

Output: unanswerable


QUES: Americans with Sub-Saharan African ancestry for historical reasons: slavery, partus sequitur ventrem, one-eighth law, the one-drop rule of 20th-century legislation, have frequently been classified as black (historically) or African American, even if they have significant European American or Native American ancestry. As slavery became a racial caste, those who were enslaved and others of any African ancestry were classified by what is termed "hypodescent" according to the lower status ethnic group. Many of majority European ancestry and appearance "married white" and assimilated into white society for its social and economic advantages, such as generations of families identified as Melungeons, now generally classified as white but demonstrated genetically to be of European and sub-Saharan African ancestry.

Why did people choose not to assimilate into white society?
What is the answer?
ANS: unanswerable


QUES: Early HDTV commercial experiments, such as NHK's MUSE, required over four times the bandwidth of a standard-definition broadcast. Despite efforts made to reduce analog HDTV to about twice the bandwidth of SDTV, these television formats were still distributable only by satellite.
How much more bandwith was required from early SDTV commercial experiments than an SD broadcast?

ANS: unanswerable


All of the highways into Wenchuan, and others throughout the province, were damaged, resulting in delayed arrival of the rescue troops. In Beichuan County, 80% of the buildings collapsed according to Xinhua News. In the city of Shifang, the collapse of two chemical plants led to leakage of some 80 tons of liquid ammonia, with hundreds of people reported buried. In the city of Dujiangyan, south-east of the epicenter, a whole school collapsed with 900 students buried and fewer than 60 survived. The Juyuan Middle School, where many teenagers were buried, was excavated by civilians and cranes. Dujiangyan is home of the Dujiangyan Irrigation System, an ancient water diversion project which is still in use and is a UNESCO World Heritage Site. The project's famous Fish Mouth was cracked but not severely damaged otherwise.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): How many of the buildings in Beichuan collapsed?
Ah, so.. 80%


Question: Defensive Counterair (DCA) is defined as "all the defensive measures designed to detect, identify, intercept, and destroy or negate enemy forces attempting to penetrate or attack through friendly airspace" (JP 1-02). A major goal of DCA operations, in concert with OCA operations, is to provide an area from which forces can operate, secure from air and missile threats. The DCA mission comprises both active and passive defense measures. Active defense is "the employment of limited offensive action and counterattacks to deny a contested area or position to the enemy" (JP 1-02). It includes both ballistic missile defense and air breathing threat defense, and encompasses point defense, area defense, and high value airborne asset defense. Passive defense is "measures taken to reduce the probability of and to minimize the effects of damage caused by hostile action without the intention of taking the initiative" (JP 1-02). It includes detection and warning; chemical, biological, radiological, and nuclear defense; camouflage, concealment, and deception; hardening; reconstitution; dispersion; redundancy; and mobility, counter-measures, and stealth.
Try to answer this question if possible: What is one of the many ways the DCA utilizes passive defense to protect from enemy attacks? 
Answer: counter-measures


Problem: Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in photochromic glasses). Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber color from a reducing combustion atmosphere. Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide. When used in art glass or studio glass is colored using closely guarded recipes that involve specific combinations of metal oxides, melting temperatures and 'cook' times. Most colored glass used in the art market is manufactured in volume by vendors who serve this market although there are some glassmakers with the ability to make their own color from raw materials.
What chemical compounds can make glass nearly black?
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Answer:
iron polysulfides