Problem: Antenna (radio):

The radiation of many antennas shows a pattern of maxima or "lobes" at various angles, separated by "nulls", angles where the radiation falls to zero. This is because the radio waves emitted by different parts of the antenna typically interfere, causing maxima at angles where the radio waves arrive at distant points in phase, and zero radiation at other angles where the radio waves arrive out of phase. In a directional antenna designed to project radio waves in a particular direction, the lobe in that direction is designed larger than the others and is called the "main lobe". The other lobes usually represent unwanted radiation and are called "sidelobes". The axis through the main lobe is called the "principal axis" or "boresight axis".

What is the term that refers to areas where an antennas radiation is zero? 
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A: nulls


Problem: In contrast, Botswana has recently been forced to ban trophy hunting following a precipitous wildlife decline. The numbers of antelope plummeted across Botswana, with a resultant decline in predator numbers, while elephant numbers remained stable and hippopotamus numbers rose. According to the government of Botswana, trophy hunting is at least partly to blame for this, but many other factors, such as poaching, drought and habitat loss are also to blame. Uganda recently did the same, arguing that "the share of benefits of sport hunting were lopsided and unlikely to deter poaching or improve [Uganda's] capacity to manage the wildlife reserves."
What animal population increased in Uganda?
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Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
For Ruskin, the aesthetic was of overriding significance. His work goes on to state that a building is not truly a work of architecture unless it is in some way "adorned". For Ruskin, a well-constructed, well-proportioned, functional building needed string courses or rustication, at the very least.
What features at minimum did Ruskin insist on for a building to be considered functional?
A: string courses or rustication


Context and question: In 1883, salt water taffy was conceived in Atlantic City by David Bradley. The traditional story is that Bradley's shop was flooded after a major storm, soaking his taffy with salty Atlantic Ocean water. He sold some "salt water taffy" to a girl, who proudly walked down to the beach to show her friends. Bradley's mother was in the back of the store when the sale was made, and loved the name, and so salt water taffy was born.
Who did Bradley sell salt water taffy to for the first time?
Answer: a girl


Question: In September 1939, Britain entered the Second World War, which lasted until 1945. During the war, many of London's children were evacuated to avoid the frequent aerial bombing. The suggestion by senior politician Lord Hailsham that the two princesses should be evacuated to Canada was rejected by Elizabeth's mother, who declared, "The children won't go without me. I won't leave without the King. And the King will never leave." Princesses Elizabeth and Margaret stayed at Balmoral Castle, Scotland, until Christmas 1939, when they moved to Sandringham House, Norfolk. From February to May 1940, they lived at Royal Lodge, Windsor, until moving to Windsor Castle, where they lived for most of the next five years. At Windsor, the princesses staged pantomimes at Christmas in aid of the Queen's Wool Fund, which bought yarn to knit into military garments. In 1940, the 14-year-old Elizabeth made her first radio broadcast during the BBC's Children's Hour, addressing other children who had been evacuated from the cities. She stated: "We are trying to do all we can to help our gallant sailors, soldiers and airmen, and we are trying, too, to bear our share of the danger and sadness of war. We know, every one of us, that in the end all will be well."
Is there an answer to this question: How old was Elizabeth's sister in 1940?

Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
All major cities have their distinctive local department stores, which anchored the downtown shopping district until the arrival of the malls in the 1960s. Washington, for example, after 1887 had Woodward & Lothrop and Garfinckel's starting in 1905. Garfield's went bankrupt in 1990, as did Woodward & Lothrop in 1994. Baltimore had four major department stores: Hutzler's was the prestige leader, followed by Hecht's, Hochschild's and Stewart's. They all operated branches in the suburbs, but all closed in the late twentieth century. By 2015, most locally owned department stores around the country had been consolidated into larger chains, or had closed down entirely.
How many major department stores did Baltimore have at the time? 
A:
four