land cover is one of basic data layers in geographic information system for physical planning and environmentalmonitoring. digital image classification is generally performed to produce land cover maps from remote sensing data,particularly for large areas. in the present study the multispectral image from irs liss-iii image along with ancillary datasuch as vegetation indices, principal componen...

in land use planning, mapping the present land use / land cover situation is a necessary tool for determining the current condition and for identifying land use trends. in this study, in order to provide a land use/ land cover map for ilam watershed, the irs-1c image data from 25th april 2006 were used. initial qualitative evaluation on data showed no significant radiometric error. ortho-rectif...

plant cover is one of the most important factors affecting infiltration rate of water into the soil and decreasing runoff. distribution of plants in arid and semi-arid areas is almost patchy and form different patterns. one of the fascinating patterns is ring-shaped growth pattern. ring patterns of varying size are formed by clonally reproducing grasses, sedges and even shrubs growing in resour...

remote sensing techniques are known as very useful methods for studying land use management in arid and semi arid areas, where undeveloped soils are dominant. these techniques can be used for determining different environmental characteristics including soil and vegetations. in this study etm+ band ratios and principal component analysis (pca) were used for monitoring of vegetation cover and it...

Using time series of Normalized Difference Vegetation Index (NDVI) and rainfall data, we investigated historical vegetation productivity trends from 1982 to 2011 over the Bani River Basin in Mali. Statistical agreements between long-term trends in vegetation productivty, corresponding rainfall and rate of land cover change from Landsat time-series imagery was used to discern climate versus huma...

The object of the present work was to identify the larval habitats of Culex eduardoi and to determine the microenvironmental conditions related to their presence in different artificial freshwater environments (temporary, semi-permanent, irrigation ditches, and drainage ditches) in tillable areas of Chubut Province, Argentina. This report represents the first record of Cx. eduardoi from this Pr...

Climate change will exacerbate the degree of abiotic stress experienced by semi-arid ecosystems. While abiotic stress profoundly affects biotic interactions, their potential role as modulators of ecosystem responses to climate change is largely unknown. Using plants and biological soil crusts, we tested the relative importance of facilitative-competitive interactions and other community attribu...

The study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. Theresearch was accomplished in semi-steppe KhoyBilehvar area, from 1999 to2005. Vegetation cover was annually measured within fixed plots during transact.The results showed that during nine...

This paper studies the cutting plane method for solving quadratic semi-innnite programming problems. Several relaxation techniques and their combinations are proposed and discussed. A exible convergence proof is provided to cover diierent settings. The implementation issues are addressed with some numerical experiments to illustrate the computational behavior of each diierent combination scheme.

The influence of semi-planar chiral metamaterial (CMM) structures on the important characteristics of circularly polarized (CP) antennas is investigated in this paper. Based on this idea, CP planar two-arm Archimedean spiral (ARSPL) antenna and helical antenna are designed and the effects of chiral covers on their gain (or directivity), axial-ratio (AR), and return loss are considered. The resu...