Question: Reflections generally affect polarization. For radio waves, one important reflector is the ionosphere which can change the wave's polarization. Thus for signals received following reflection by the ionosphere (a skywave), a consistent polarization cannot be expected. For line-of-sight communications or ground wave propagation, horizontally or vertically polarized transmissions generally remain in about the same polarization state at the receiving location. Matching the receiving antenna's polarization to that of the transmitter can make a very substantial difference in received signal strength.
Try to answer this question if possible: What is the name used for signals recieved following reflection by the ionosphere?
Answer: a skywave
Question: Although the drafts of both the Maastricht treaty and the Treaty establishing a Constitution for Europe mentioned federalism, the representatives of the member countries (all of whom would have had to agree to use of the term) never formally adopted it. The strongest advocates of European federalism have been Germany, Italy, Belgium and Luxembourg while those historically most strongly opposed have been the United Kingdom, Denmark and France (with conservative presidents and governments). Since the presidency of Francois Mitterrand (1981-1995), the French authorities have adopted a much more pro-European Unification position, as they consider that a strong EU is presenting the best "insurance" against a unified Germany which might become too strong and thus a threat for its neighbours.
Try to answer this question if possible: When did the French authorities adopted the pro-European Unification position?
Answer: Since the presidency of Francois Mitterrand (1981-1995
Question: The term "classical music" did not appear until the early 19th century, in an attempt to distinctly canonize the period from Johann Sebastian Bach to Beethoven as a golden age. The earliest reference to "classical music" recorded by the Oxford English Dictionary is from about 1836.
Try to answer this question if possible: In what book was the earliest reference to classical music?
Answer: Oxford English Dictionary
Question: The Protocol on Environmental Protection to the Antarctic Treaty (also known as the Environmental Protocol or Madrid Protocol) came into force in 1998, and is the main instrument concerned with conservation and management of biodiversity in Antarctica. The Antarctic Treaty Consultative Meeting is advised on environmental and conservation issues in Antarctica by the Committee for Environmental Protection. A major concern within this committee is the risk to Antarctica from unintentional introduction of non-native species from outside the region.
Try to answer this question if possible: When did the Environmental Protocol become effective?
Answer:
1998