Environmental extreme events detection: A survey

The application of statistics in extreme events detection is quite diverse and leads to diverse formulations, which needs to be designed for the specific problem. Each formula needs to be tailored specifically to work with the available data in the given situation. This diversity is one of the driving forces of this survey towards identifying the most common mixture of components utilized in the analysis of environmental outlier detection. Indeed for some arbitrary applications, it may not always be possible to use off-the-shelf models due to the wide variations in problem formulations. In this paper, we summarize the statistical methods involved in the detection of environmental extremes such as wind ramps, high precipitation and extreme temperatures. Then we organize the discussion along different outlier detection types, present various outlier definitions, and briefly introduce the corresponding techniques. Environmental extreme events detection challenges and possible future work are also discussed.

Effects of heat and cold on the albino rat: crossed resistance or crossed sensitization?

Two experiments were carried out to test whether or not cold-acclimatized rats adjust better to heat and heat-acclimatized rats adjust better to cold than rats not previously exposed to either environmental extreme. In both, groups of rats were exposed to 94.5°–96.5℉ (hot), 33°–40℉ (cold) and 76°–78℉ (control). In the first experiment 45 female Holtzman littermates were used. After 50 days, ‘hot’ rats were abruptly transferred to cold, ‘cold’ rats to heat. Control animals were also placed in each environment. In the second experiment 55 identical rats were similarly treated; the cross, however, was made after 29 days. Rats exposed to 95℉ exhibited sustained hypothermia. Rats exposed to 36℉ developed a transient hypothermia which lasted longer in the first experiment than in the second and was accompanied by more severe cold injury. Heat was not a stress in the sense of Selye, but cold was. There was crossed sensitization rather than crossed resistance. Submitted on January 26, 1959