The analysis of vegetation dynamics is essential in semi-arid regions, in particular because of the frequent occurrence of long periods of drought. In this paper, multi-temporal series of the Normalized Difference of Vegetation Index (NDVI), derived from SPOT-VEGETATION satellite data between September 1998 and June 2010, were used to analyze the vegetation dynamics over the semi-arid central r...

At a site in the northwestern Sonoran Desert the percent ground cover for the C $ subshrub Encelia farinosa was eighttimes higher on more arid 20° south-facing slopes than on 20° north-facing slopes at 820 m elevation, and was sixtimes higher on north-facing slopes at a 300-m-lower elevation, also the more arid condition. The ground cover of the C % bunchgrass Pleuraphis rigida decreased over 5...

Castor (Ricinus communis L.) is an important non-edible oilseed crop of Euphorbiaceae family. Castor has enormous significance in the country as it plays an important role in the agricultural economies because it enables them to earn substantial foreign exchange through export of castor beans and oils. It is believed that castor is indigenous to the southeastern Mediterranean Basin, Eastern Afr...

The common spiny mouse Acomys cahirinus, of Ethiopian origin, has a widespread distribution across arid, semi-arid and Mediterranean parts of the Arabian sub-region. We compared the daily energy expenditure (DEE), water turnover (WTO) and sustained metabolic scope (SusMS=DEE/resting metabolic rate) of two adjacent populations during the winter. Mice were captured from North- and South- facing s...

Few studies have focused on Rift Valley fever virus (RVFV) transmission in less arid, transitional landscapes surrounding known high-risk regions. The objective of this study was to identify evidence of RVFV exposure in Bodhei Village in a forested area at the edge of the RVFV-epidemic Garissa region. In a household cluster-based survey conducted between epidemics in early 2006, 211 participant...

Citrus is produced commercially in over 30 countries worldwide. The major growing regions are located primarily between 40° north-south latitude where minimum temperature is generally greater than 20°F. Within these latitudes there are several important climatic areas that affect the growth and development, yields, and fruit quality of citrus. These include the low, middle, and high tropical re...

accurate estimation of evaporation is important for design, planning and operation of water systems. in arid zones where water resources are scarce, the estimation of this loss becomes more interesting in the planning and management of irrigation practices. this paper investigates the ability of artificial neural networks (anns) technique to improve the accuracy of daily evaporation estimation....