41. First, it has to be placed near active areas , which can be difficult to locate. 42. Practical non-Foster networks are an active area of research. 43. The eastern Sierra has been a seismically active area . 44. Social trap research continues to be an active area . 45. The islands are in one of the more seismically active areas of the Southern Hemisphere, 46. Noncommutative rings serve as an active area of research due to their ubiquity in mathematics. 47. An example of an active area of research in algebraic number theory is Iwasawa theory. 48. They said a major earthquake in the seismically active area could lead to a catastrophe. 49. Abstract regular polytopes remain an active area of research. 50. The Phoenix area is an active area for counterfeiting, partly because of its proximity to Mexico.
