Problem: Railway electrification system:

There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union.

Which type of power does require three-phase transmission?
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A: AC


Problem:  In 1955, DC Sinclair and G Weddell developed peripheral pattern theory, based on a 1934 suggestion by John Paul Nafe. They proposed that all skin fiber endings (with the exception of those innervating hair cells) are identical, and that pain is produced by intense stimulation of these fibers. Another 20th-century theory was gate control theory, introduced by Ronald Melzack and Patrick Wall in the 1965 Science article "Pain Mechanisms: A New Theory". The authors proposed that both thin (pain) and large diameter (touch, pressure, vibration) nerve fibers carry information from the site of injury to two destinations in the dorsal horn of the spinal cord, and that the more large fiber activity relative to thin fiber activity at the inhibitory cell, the less pain is felt. Both peripheral pattern theory and gate control theory have been superseded by more modern theories of pain[citation needed].
What did DC Sinclair and G Weddell propose a property of all skin fiber endings is?
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Answer: identical


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The Times was founded by publisher John Walter on 1 January 1785 as The Daily Universal Register, with Walter in the role of editor. Walter had lost his job by the end of 1784 after the insurance company where he was working went bankrupt because of the complaints of a Jamaican hurricane. Being unemployed, Walter decided to set a new business up. It was in that time when Henry Johnson invented the logography, a new typography that was faster and more precise (three years later, it was proved that it was not as efficient as had been said). Walter bought the logography's patent and to use it, he decided to open a printing house, where he would daily produce an advertising sheet. The first publication of the newspaper The Daily Universal Register in Great Britain was 1 January 1785. Unhappy because people always omitted the word Universal, Ellias changed the title after 940 editions on 1 January 1788 to The Times. In 1803, Walter handed ownership and editorship to his son of the same name. Walter Sr had spent sixteen months in Newgate Prison for libel printed in The Times, but his pioneering efforts to obtain Continental news, especially from France, helped build the paper's reputation among policy makers and financiers.
Before the newspaper changed its name to The Times, how many editions were printed?
A: 940


Context and question: In April, during the Revolution of 1848 in Paris, he left for London, where he performed at several concerts and at numerous receptions in great houses. This tour was suggested to him by his Scottish pupil Jane Stirling and her elder sister. Stirling also made all the logistical arrangements and provided much of the necessary funding.
Where did Chopin head to during the Revolution of 1848?
Answer: London


Question: UNFPA is the world's largest multilateral source of funding for population and reproductive health programs. The Fund works with governments and non-governmental organizations in over 150 countries with the support of the international community, supporting programs that help women, men and young people:
Is there an answer to this question: UNFPA is the largest worldwide funder of what type of programs?

Answer: population and reproductive health programs


QUES: In 1952, Thomas Watson, Sr., stepped down after almost 40 years at the company helm; his son, Thomas Watson, Jr., was named president. In 1956, the company demonstrated the first practical example of artificial intelligence when Arthur L. Samuel of IBM's Poughkeepsie, New York, laboratory programmed an IBM 704 not merely to play checkers but "learn" from its own experience. In 1957, the FORTRAN (FORmula TRANslation) scientific programming language was developed. In 1961, Thomas J. Watson, Jr., was elected chairman of the board and Albert L. Williams became company president. The same year IBM developed the SABRE (Semi-Automatic Business-Related Environment) reservation system for American Airlines and introduced the highly successful Selectric typewriter.

In 1956 the company demonstrated the first example of what?
What is the answer?
ANS:
artificial intelligence