Problem: Glass:

Following the glass batch preparation and mixing, the raw materials are transported to the furnace. Soda-lime glass for mass production is melted in gas fired units. Smaller scale furnaces for specialty glasses include electric melters, pot furnaces, and day tanks. After melting, homogenization and refining (removal of bubbles), the glass is formed. Flat glass for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish. Container glass for common bottles and jars is formed by blowing and pressing methods. This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance. Further glass forming techniques are summarized in the table Glass forming techniques.

What is used on the surface of window glass to make it smooth?
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A: nitrogen


Problem: Daylight saving time:

Older or stripped-down systems may support only the TZ values required by POSIX, which specify at most one start and end rule explicitly in the value. For example, TZ='EST5EDT,M3.2.0/02:00,M11.1.0/02:00' specifies time for the eastern United States starting in 2007. Such a TZ value must be changed whenever DST rules change, and the new value applies to all years, mishandling some older timestamps.

What does the TZ value EST5EDT,M3.2.0/02:00,M11.1.0/02:00 specify?
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A: time for the eastern United States starting in 2007


Problem: Guinea-Bissau:

Guinea-Bissau was once part of the kingdom of Gabu, as well as part of the Mali Empire. Parts of this kingdom persisted until the 18th century, while a few others were under some rule by the Portuguese Empire since the 16th century. In the 19th century, it was colonized as Portuguese Guinea. Upon independence, declared in 1973 and recognised in 1974, the name of its capital, Bissau, was added to the country's name to prevent confusion with Guinea (formerly French Guinea). Guinea-Bissau has a history of political instability since independence, and no elected president has successfully served a full five-year term.

What year was Guinea-Bissau declared independent?
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A: 1973


Problem: Financial crisis of 2007%E2%80%9308:

Lower interest rates encouraged borrowing. From 2000 to 2003, the Federal Reserve lowered the federal funds rate target from 6.5% to 1.0%. This was done to soften the effects of the collapse of the dot-com bubble and the September 2001 terrorist attacks, as well as to combat a perceived risk of deflation. As early as 2002 it was apparent that credit was fueling housing instead of business investment as some economists went so far as to advocate that the Fed "needs to create a housing bubble to replace the Nasdaq bubble". Moreover, empirical studies using data from advanced countries show that excessive credit growth contributed greatly to the severity of the crisis.

What contributed greatly to the severity of the financial crisis of 2007?
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A:
excessive credit growth