BACKGROUND AND SPECIFIC AIMS The study of physiological adaptation and diversity has been a central issue in ecological and evolutionary physiology. For example, the environmental tuning of an organism’s physiology is often hypothesized to be responsible for allowing an organism to adjust to changing biotic and abiotic conditions, through increases in physiological performance. This is well exe...

A central problem in archaeological research has been the chronometric dating of petroglyphs (rock engravings). Recent improvements in the understanding of the chemistry of rock varnish (or patina) that develops on rock surfaces in arid regions has resulted in the development of a calibrated dating technique, cation-ratio (CR) dating. This is based on calibrating chemical changes in minor and m...

Milk consumption in the semi-arid regions of Kenya is not well understood. A study was carried out on consumption of milk and milk products in the semi-arid region of eastern Kenya. A total of 135 rural and 126 urban households were interviewed. Raw milk was the most popular and was consumed by 99% and 84% of rural and urban households, respectively. Generally as degree of processing increased,...

Biological soil crusts play important ecological functions in arid and semi-arid regions, while different crust successional patterns appeared in different regions. Therefore in this study, the environmental conditions between Shapotou (with cyanobacterial, lichen and moss crusts) and Dalate Banner (with only cyanobacterial and moss crusts) regions of China were compared to investigate why lich...

A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion and capture relative to groundwater withdrawals (extraction or pumpage) have not previously been well characterized. This study assesses the partitioning of long-term cumulative withdrawal volumes into fractions derived from storage deple...

A brief analysis on the distribution range of some of the species dominating in the arid and extra arid regions of North Africa and Arabian Peninsula is presented. These species are belonging to three phytogeographical categories namely: Saharo-Sindian, Sudano-Deccanian and Tropical African-Indian elements. Species included for this study are either disjunct or they have a wider distribution, s...

abstract a basic aim of low energy architecture is to create a thermally comfortable internal environment for building occupants whilst consuming the least possible amount of energy. in desert countries this aim is more difficult to achieve since high ambient air temperatures create a barrier to comfort. traditional building types of these countries, such as courtyard building, have evolved to ...

Mineral dust is a contributor of the global aerosol budget, with arid regions as principal sources. IPCC (2007) gives a best estimate of the direct mineral dust radiative forcing (RF), with the highest uncertainty in the radiative balance estimations being associated to mineral dust for both its direct and indirect effects. In addition, differentiating the anthropogenic influenced dust has impo...

The modern European climatic regime is peculiar, due to its unitary winter but diverse summer climates and a pronounced Mediterranean climate in the south. However, little is known on its evolution in the deep time. Here we reconstruct the European summer climate conditions in the Tortonian (11.62-7.246 Ma) using plant fossil assemblages from 75 well-dated sites across Europe. Our results clear...