climate is the most important factor which control desertification .in order to detect climate changes in desert zones, time trend analysis is applied to extreme indices in kashan station using extreme climate index software (ecis). results show significant trends in extreme indices during the past decade 1995-2004 and the pronounced warming is associated with a negative trend in cold extremes....

BACKGROUND The level of environmental hypobaric hypoxia that affects climbers at the summit of Mount Everest (8848 m [29,029 ft]) is close to the limit of tolerance by humans. We performed direct field measurements of arterial blood gases in climbers breathing ambient air on Mount Everest. METHODS We obtained samples of arterial blood from 10 climbers during their ascent to and descent from t...

AIMS Eighteen patients with asthma were evaluated during preparation to climb to extreme altitude in order to study the effects of low fractional inspired oxygen (FiO(2)), prolonged exposure to cold air and high altitude on lung function, asthma control and airway inflammation. METHODS Spirometry and airway inflammation (fractional exhaled nitric oxide (FeNO) and induced sputum) were studied ...

The Agabus bipustulatus complex includes one of Europe's most widely distributed and common diving beetles. This complex, which is known for its large morphological variation, has a complex demographic and altitudinal variation in elytral reticulation. The various depth of the reticulation imprint, both in smaller and larger meshes, results in both mat and shiny individuals, as well as intermed...

Barren high-altitude soils are among the most extreme terrestrial environments on Earth. The present study was undertaken to quantify broad-scale patterns of total microbial biomass in unvegetated soils in the subnival zone of the Colorado Front Range and the high Andes of Perú. In order to better understand the limiting factors and substrates used by this community, we measured microbial bioma...

Tibetan sheep have lived on the Tibetan Plateau for thousands of years; however, the process and consequences of adaptation to this extreme environment have not been elucidated for important livestock such as sheep. Here, seven sheep breeds, representing both highland and lowland breeds from different areas of China, were genotyped for a genome-wide collection of single-nucleotide polymorphisms...

Freshwater lymnaeid snails are crucial in defining transmission and epidemiology of fascioliasis. In South America, human endemic areas are related to high altitudes in Andean regions. The species Lymnaea diaphana has, however, been involved in low altitude areas of Chile, Argentina and Peru where human infection also occurs. Complete nuclear ribosomal DNA 18S, internal transcribed spacer (ITS)...

Carrying heavy loads in the Himalayan region is a real challenge. Porters face extreme ranges in terrain condition, path steepness, altitude hypoxia and climate for 6-8h a day, many months a year, since they were boys. It has been previously shown that, when carrying loads on level terrain, porters' metabolic economy is higher than in Caucasians but the reasons are still unknown. We monitored N...

In previous work, a matched-field estimate of aircraft altitude which uses multiple over-the-horizon radar dwells was presented. This approach exploited the altitude dependent structure of the micro-multipath rays which result from reflections local to the aircraft. While it was shown that the multi-dwell matched-field estimate is able to accurately estimate altitude while using typical radar p...

Warfighter exposure to high terrestrial altitude continues to be a reality for the modern fighting force. Understanding the negative effects of altitude on cognitive performance is essential as the cognitive demands of many warfighting tasks are becoming increasingly complex. To date, little research has investigated the performance of multiple cognitive tasks in a high altitude environment. Th...