Article: Ancient tables provided the sun's mean longitude. Christopher Clavius, the architect of the Gregorian calendar, noted that the tables agreed neither on the time when the sun passed through the vernal equinox nor on the length of the mean tropical year. Tycho Brahe also noticed discrepancies. The Gregorian leap year rule (97 leap years in 400 years) was put forward by Petrus Pitatus of Verona in 1560. He noted that it is consistent with the tropical year of the Alfonsine tables and with the mean tropical year of Copernicus (De revolutionibus) and Reinhold (Prutenic tables). The three mean tropical years in Babylonian sexagesimals as the excess over 365 days (the way they would have been extracted from the tables of mean longitude) were 14,33,9,57 (Alphonsine), 14,33,11,12 (Copernicus) and 14,33,9,24 (Reinhold). All values are the same to two places (14:33) and this is also the mean length of the Gregorian year. Thus Pitatus' solution would have commended itself to the astronomers.

Question: Who was the architect of the Gregorian calendar?
Ans: Christopher Clavius


Article: In the tree a knot is either the base of a side branch or a dormant bud. A knot (when the base of a side branch) is conical in shape (hence the roughly circular cross-section) with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud.

Question: What measurement of a stem determines a knot's inner tip placement?
Ans: diameter


Article: The foundation explains on its website that its trustees divided the organization into two entities: the Bill & Melinda Gates Foundation (foundation) and the Bill & Melinda Gates Foundation Trust (trust). The foundation section, based in Seattle, US, "focuses on improving health and alleviating extreme poverty," and its trustees are Bill and Melinda Gates and Warren Buffett. The trust section manages "the investment assets and transfer proceeds to the foundation as necessary to achieve the foundation's charitable goals"—it holds the assets of Bill and Melinda Gates, who are the sole trustees, and receives contributions from Buffett.

Question: What does the Trust entity focus on 
Ans: The trust section manages "the investment assets and transfer proceeds to the foundation as necessary to achieve the foundation's charitable goals


Article: Increasing military and cultural contacts with the Muslim world, including the Norman conquest of Islamic Sicily in 1090, the Crusades, beginning 1096, and the Islamic presence in Spain, may have influenced Medieval Europe's adoption of the pointed arch, although this hypothesis remains controversial. Certainly, in those parts of the Western Mediterranean subject to Islamic control or influence, rich regional variants arose, fusing Romanesque and later Gothic traditions with Islamic decorative forms, as seen, for example, in Monreale and Cefalù Cathedrals, the Alcázar of Seville, and Teruel Cathedral.

Question: What is one cathedral in which the mixing of Romanesque, Gothic and Islamic styles can be seen?
Ans:
Cefalù Cathedrals