one of the main objectives of ecosystem management is to preserve the speciesdiversity. many researchers regard higher species diversity as the stability of ecologicalsystems. the aim of this study is to investigate the stability and relationships betweentopographical factors with diversity indices in ghorkhud mountainous rangeland innorthern khorasan province, iran. for data sampling (2012), l...

in many studies, topographic factors have been considered as an important factor in establishing the vegetation in different ecosystems. so, it affects vegetation composition and diversity by influencing soil moisture, fertility and soil depth. the aim of this research was to investigate the effects of slope, elevation and geographical aspects on species growth, forage production and vegetation...

PURPOSE To develop a criterion for determining the topographic progression of keratoconus and to analyze the prognostic factors of progression. METHODS Medical records of 211 eyes of 128 patients who had been followed up for more than 2 years on three or more occasions were retrospectively reviewed. Topographic parameters, including simulated K, corneal astigmatism, irregular astigmatism at 3...

The expanding phenomenon of dieback is caused by the reaction of trees against the harmful biotic and a biotic factor that lead to dying of shoots and branches of trees from upper crown to lower crown. This phenomenon spreads throughout the leaves and branches and all parts of the plant and may finally lead to the death of the plant. This study aimed to identify species dieback especially Carpi...

One of the main objectives of ecosystem management is to preserve the speciesdiversity. Many researchers regard higher species diversity as the stability of ecologicalsystems. The aim of this study is to investigate the stability and relationships betweentopographical factors with diversity indices in Ghorkhud mountainous rangeland innorthern Khorasan province, Iran. For data sampling (2012), l...

............................................................................................................................................... 4 Introduction .......................................................................................................................................... 4 The Grounded Theory Method..........................................................................

Landslide is one of the natural disasters that occur in Malaysia. Topographic factors such as elevation, slope angle, slope aspect, general curvature, plan curvature, and profile curvature are considered as the main causes of landslides. In order to determine the dominant topographic factors in landslide mapping analysis, a study was conducted and presented in this paper. There are three main s...