Problem: Data compression:

Lossless data compression algorithms usually exploit statistical redundancy to represent data without losing any information, so that the process is reversible. Lossless compression is possible because most real-world data exhibits statistical redundancy. For example, an image may have areas of colour that do not change over several pixels; instead of coding "red pixel, red pixel, ..." the data may be encoded as "279 red pixels". This is a basic example of run-length encoding; there are many schemes to reduce file size by eliminating redundancy.

What may have colors that do not change over several pixels?
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A: an image


Problem: The British high-definition TV service started trials in August 1936 and a regular service on 2 November 1936 using both the (mechanical) Baird 240 line sequential scan (later to be inaccurately rechristened 'progressive') and the (electronic) Marconi-EMI 405 line interlaced systems. The Baird system was discontinued in February 1937. In 1938 France followed with their own 441-line system, variants of which were also used by a number of other countries. The US NTSC 525-line system joined in 1941. In 1949 France introduced an even higher-resolution standard at 819 lines, a system that should have been high definition even by today's standards, but was monochrome only and the technical limitations of the time prevented it from achieving the definition of which it should have been capable. All of these systems used interlacing and a 4:3 aspect ratio except the 240-line system which was progressive (actually described at the time by the technically correct term "sequential") and the 405-line system which started as 5:4 and later changed to 4:3. The 405-line system adopted the (at that time) revolutionary idea of interlaced scanning to overcome the flicker problem of the 240-line with its 25 Hz frame rate. The 240-line system could have doubled its frame rate but this would have meant that the transmitted signal would have doubled in bandwidth, an unacceptable option as the video baseband bandwidth was required to be not more than 3 MHz.
 When was the Baird system created?
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Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In September 2008, the crisis hit its most critical stage. There was the equivalent of a bank run on the money market funds, which frequently invest in commercial paper issued by corporations to fund their operations and payrolls. Withdrawal from money markets were $144.5 billion during one week, versus $7.1 billion the week prior. This interrupted the ability of corporations to rollover (replace) their short-term debt. The U.S. government responded by extending insurance for money market accounts analogous to bank deposit insurance via a temporary guarantee and with Federal Reserve programs to purchase commercial paper. The TED spread, an indicator of perceived credit risk in the general economy, spiked up in July 2007, remained volatile for a year, then spiked even higher in September 2008, reaching a record 4.65% on October 10, 2008.
What do money market funds frequently invest in?
A: commercial paper issued by corporations


Context and question: On September 21, 1953, Thomas Watson, Jr., the company's president at the time, sent out a controversial letter to all IBM employees stating that IBM needed to hire the best people, regardless of their race, ethnic origin, or gender. He also publicized the policy so that in his negotiations to build new manufacturing plants with the governors of two states in the U.S. South, he could be clear that IBM would not build "separate-but-equal" workplaces. In 1984, IBM added sexual orientation to its nondiscrimination policy. The company stated that this would give IBM a competitive advantage because IBM would then be able to hire talented people its competitors would turn down.
What date did Thomas Watson, Jr. send out a letter about IBM hiring the best people regardless of race, gender, or origin?
Answer: September 21, 1953


Question: The semi-finals have been played exclusively at the rebuilt Wembley Stadium since 2008, one year after it opened and after it had already hosted a final (in 2007). For the first decade of the competition, the Kennington Oval was used as the semi-final venue. In the period between this first decade and the reopening of Wembley, semi-finals were played at high-capacity neutral venues around England; usually the home grounds of teams not involved in that semi-final, chosen to be roughly equidistant between the two teams for fairness of travel. The top three most used venues in this period were Villa Park in Birmingham (55 times), Hillsborough in Sheffield (34 times) and Old Trafford in Manchester (23 times). The original Wembley Stadium was also used seven times for semi-final, between 1991 and 2000 (the last held there), but not always for fixtures featuring London teams. In 2005, both were held at the Millennium Stadium.
Is there an answer to this question: What were the three least used venues?

Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The cult centers of Apollo in Greece, Delphi and Delos, date from the 8th century BCE. The Delos sanctuary was primarily dedicated to Artemis, Apollo's twin sister. At Delphi, Apollo was venerated as the slayer of Pytho. For the Greeks, Apollo was all the Gods in one and through the centuries he acquired different functions which could originate from different gods. In archaic Greece he was the prophet, the oracular god who in older times was connected with "healing". In classical Greece he was the god of light and of music, but in popular religion he had a strong function to keep away evil. Walter Burkert discerned three components in the prehistory of Apollo worship, which he termed "a Dorian-northwest Greek component, a Cretan-Minoan component, and a Syro-Hittite component."
To whom was the Delos sanctuary dedicated?
A:
Artemis