Input: Read this: Portugal has several summer music festivals, such as Festival Sudoeste in Zambujeira do Mar, Festival de Paredes de Coura in Paredes de Coura, Festival Vilar de Mouros near Caminha, Boom Festival in Idanha-a-Nova Municipality, Optimus Alive!, Sumol Summer Fest in Ericeira, Rock in Rio Lisboa and Super Bock Super Rock in Greater Lisbon. Out of the summer season, Portugal has a large number of festivals, designed more to an urban audience, like Flowfest or Hip Hop Porto. Furthermore, one of the largest international Goa trance festivals takes place in central Portugal every two years, the Boom Festival, that is also the only festival in Portugal to win international awards: European Festival Award 2010 – Green'n'Clean Festival of the Year and the Greener Festival Award Outstanding 2008 and 2010. There is also the student festivals of Queima das Fitas are major events in a number of cities across Portugal. In 2005, Portugal held the MTV Europe Music Awards, in Pavilhão Atlântico, Lisbon.
Question: What is the Boom Festival?

Output: one of the largest international Goa trance festivals takes place in central Portugal every two years


QUES: One of the Han's greatest mathematical advancements was the world's first use of negative numbers. Negative numbers first appeared in the Nine Chapters on the Mathematical Art as black counting rods, where positive numbers were represented by red counting rods. Negative numbers are used in the Bakhshali manuscript of ancient India, but its exact date of compilation is unknown. Negative numbers were also used by the Greek mathematician Diophantus in about 275 AD, but were not widely accepted in Europe until the 16th century AD.

In what treatise did negative numbers first appear?
What is the answer?
ANS: the Nine Chapters on the Mathematical Art


QUES: Animals that characterize the Appalachian forests include five species of tree squirrels. The most commonly seen is the low to moderate elevation eastern gray squirrel (Sciurus carolinensis). Occupying similar habitat is the slightly larger fox squirrel (Sciurus niger) and the much smaller southern flying squirrel (Glaucomys volans). More characteristic of cooler northern and high elevation habitat is the red squirrel (Tamiasciurus hudsonicus), whereas the Appalachian northern flying squirrel (Glaucomys sabrinus fuscus), which closely resembles the southern flying squirrel, is confined to northern hardwood and spruce-fir forests.
Which species is commonly found more in spruce-fir forests?

ANS: Appalachian northern flying squirrel


Shōen holders had access to manpower and, as they obtained improved military technology (such as new training methods, more powerful bows, armor, horses, and superior swords) and faced worsening local conditions in the ninth century, military service became part of shōen life. Not only the shōen but also civil and religious institutions formed private guard units to protect themselves. Gradually, the provincial upper class was transformed into a new military elite based on the ideals of the bushi (warrior) or samurai (literally, one who serves).
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Which class became a new military elite?
Ah, so.. provincial upper class


Question: The war's end swung the pendulum back. Farmers continued to dislike DST, and many countries repealed it after the war. Britain was an exception: it retained DST nationwide but over the years adjusted transition dates for several reasons, including special rules during the 1920s and 1930s to avoid clock shifts on Easter mornings. The US was more typical: Congress repealed DST after 1919. President Woodrow Wilson, like Willett an avid golfer, vetoed the repeal twice but his second veto was overridden. Only a few US cities retained DST locally thereafter, including New York so that its financial exchanges could maintain an hour of arbitrage trading with London, and Chicago and Cleveland to keep pace with New York. Wilson's successor Warren G. Harding opposed DST as a "deception". Reasoning that people should instead get up and go to work earlier in the summer, he ordered District of Columbia federal employees to start work at 08:00 rather than 09:00 during summer 1922. Some businesses followed suit though many others did not; the experiment was not repeated.
Try to answer this question if possible: What U.S. city kept observing DST to stay in sync with London, leading Chicago and Cleveland to follow along?
Answer: New York


Problem: Railways must operate at variable speeds. Until the mid 1980s this was only practical with the brush-type DC motor, although such DC can be supplied from an AC catenary via on-board electric power conversion. Since such conversion was not well developed in the late 19th century and early 20th century, most early electrified railways used DC and many still do, particularly rapid transit (subways) and trams. Speed was controlled by connecting the traction motors in various series-parallel combinations, by varying the traction motors' fields, and by inserting and removing starting resistances to limit motor current.
What is speed limit for railways?
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Answer:
variable speeds