Inappropriate land use has caused a series of environmental disasters such as floods and sand storms, and some of them involved unused land changes with highly localized distributions in arid and semi-arid regions with fragile ecosystems. As the third-rank category of first-level land use/cover in China, unused land (UL) is now playing an increasingly important role in protection of the natural...

We consider whether current notions about superstring theory below the Planck scale are compatible with cosmology. We find that the anticipated form for the dilaton interaction creates a serious roadblock for inflation and makes it unlikely that the universe ever reaches a state with zero cosmological constant and time-independent gravitational constant. Superstring theories have been extensive...

Biodiversity in agricultural landscapes can be increased with conversion of some production lands into 'more-natural'- unmanaged or extensively managed - lands. However, it remains unknown to what extent biodiversity can be enhanced by altering landscape pattern without reducing agricultural production. We propose a framework for this problem, considering separately compositional heterogeneity ...

Spatially-explicit depictions of plant productivity over large areas are critical to monitoring landscapes in highly heterogeneous arid ecosystems. Applying radiometric change detection techniques we sought to determine whether: (1) differences between preand post-growing season spectral vegetation index values effectively identify areas of significant change in vegetation; and (2) areas of sig...

Population is a phenomenon ever changing more positively rather than the vice versa. It increasing in Asian countries. The increase of population Asia not compatible with geographical size and capacity countries concerned. Through process urbanization, form migration, large number people have left their birth lands for cities new lands. Such change over contributes to overpopulation, pollution ...

northern khorasan province is located in north-east iran. according to demarton coefficient, it is a semiarid region. arid and semi-arid or subhumid zones are characterized by temperature variations, low and erratic rainfall, periodic droughts and different associations of vegetative cover and soils. this article looks at current dry lands and general guidelines for finding the best area for dr...