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Assistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to the very high bandwidth fiber links that form the Internet backbone. For some time, computers were commonly equipped with IrDA interfaces, which allowed them to send and receive data to nearby machines via infrared.
How are LEDs used in theaters?
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The answer: to send sound to listeners' receivers

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The allies' most advanced technologies were showcased by the anti-aircraft defence against the German V-1 cruise missiles (V stands for Vergeltungswaffe, "retaliation weapon"). The 419th and 601st Antiaircraft Gun Battalions of the US Army were first allocated to the Folkestone-Dover coast to defend London, and then moved to Belgium to become part of the "Antwerp X" project. With the liberation of Antwerp, the port city immediately became the highest priority target, and received the largest number of V-1 and V-2 missiles of any city. The smallest tactical unit of the operation was a gun battery consisting of four 90 mm guns firing shells equipped with a radio proximity fuse. Incoming targets were acquired and automatically tracked by SCR-584 radar, developed at the MIT Rad Lab. Output from the gun-laying radar was fed to the M-9 director, an electronic analog computer developed at Bell Laboratories to calculate the lead and elevation corrections for the guns. With the help of these three technologies, close to 90% of the V-1 missiles, on track to the defence zone around the port, were destroyed.
What city got attacked by more V-1 and V-2 missiles than any other?
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The answer: Antwerp

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Some socialists such as H. D. Dickinson and Oskar Lange, responded by invoking general equilibrium theory, which they argued disproved Mises's thesis. They noted that the difference between a planned and a free market system lay in who was responsible for solving the equations. They argued, if some of the prices chosen by socialist managers were wrong, gluts or shortages would appear, signalling them to adjust the prices up or down, just as in a free market. Through such a trial and error, a socialist economy could mimic the efficiency of a free market system, while avoiding its many problems.
According to those who argued against Hayek, what sets planned and free markets apart is what?
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The answer: who was responsible for solving the equations

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Since their domestication, a large number of breeds of chickens have been established, but with the exception of the white Leghorn, most commercial birds are of hybrid origin. In about 1800, chickens began to be kept on a larger scale, and modern high-output poultry farms were present in the United Kingdom from around 1920 and became established in the United States soon after the Second World War. By the mid-20th century, the poultry meat-producing industry was of greater importance than the egg-laying industry. Poultry breeding has produced breeds and strains to fulfil different needs; light-framed, egg-laying birds that can produce 300 eggs a year; fast-growing, fleshy birds destined for consumption at a young age, and utility birds which produce both an acceptable number of eggs and a well-fleshed carcase. Male birds are unwanted in the egg-laying industry and can often be identified as soon as they are hatch for subsequent culling. In meat breeds, these birds are sometimes castrated (often chemically) to prevent aggression. The resulting bird, called a capon, has more tender and flavorful meat, as well.
Are there any purebreed lines for poultry today?
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The answer:
with the exception of the white Leghorn, most commercial birds are of hybrid origin.