Soil erosion and sand movement is one of environmental threats of the desert areas and vegetation partially prevents the creation of this phenomenon. One of the most important species growing in Sabzevar desert plains and sandy dunes, regarding too dense canopy and their root density, which have a considerable impact on soil protection and prevent movement of sands, is Stipagrostis pennata. ...

insurers have in the past few decades faced longevity risks - the risk that annuitants survive more than expected - and therefore need a new approach to manage this new risk. in this dissertation we survey methods that hedge longevity risks. these methods use securitization to manage risk, so using modern financial and insurance pricing models, especially wang transform and actuarial concepts, ...

Grazing effect on vegetation cover and soil factors in natural environments is inevitable. The present study was conducted to investigate the effect of grazing on soil factors and distribution of plant species in grazed and non-grazed areas in rangelands of western parts of Hoz-e-Soltan Lake, Qom. Systematic-randomized sampling method was used alongside of 4 transects. Adjacent to the transects...

Resistance to surface flow such as Manning's and Darcy-Weisbach rouphness coefficients were an important input for estimating soil erosion by soil erosion process models. Also, it is very important for designing and implementing soil and water conservation practices. The objective of present research was predicting Manning's and Darcy-Weisbach rouphness coefficients in surface of a loess soil u...

Fire affects vegetation and changes plant succession. In this paper, the vegetation of Sirachal Research Station, which burned in the summer of 2014, was studied and compared with the unburnt areas, based on biodiversity indices. The research was implemented as a factorial experiment in a completely randomized design. First, on the basis of physiognomy, the area was divided into three parts: sh...