نتایج جستجو برای: diversity index
تعداد نتایج: 577656 فیلتر نتایج به سال:
index tracking is the process of developing a portfolio that reproduces the performance of an index. the tracker portfolio has relatively good diversity and low turnover and low transaction costs. in this paper we applied a binary programming model for index tracking problem. in this model the number of assets for portfolio construction is defined by portfolio manager. the robust optimization f...
the coastal areas are highly productive system that is degrading due to receiving huge amount of various pollutants. despite of the important of north caspian sea estuaries the quality index of benthic fauna received less attention. in this survey the benthic population of 18 rivers estuaries in southern caspian sea were investigated. the benthic sampling and identification were conducted at ei...
abstract information about the spatial patterns of soil biodiversity is limited though required, e.g. for understanding effects of biodiversity on ecosystem processes. this study was conducted to determine whether soil macrofauna biodiversity parameters display spatial patterns in the riparian forest landscape of karkhe. soil macrofauna were sampled using 200 sampling point along parallel trans...
The use of remote sensing techniques as a suitable solution to estimate the levels of species diversity is of high importance for the sustainable management of forests. In order to investigate the potential of using sensor data from Landsat 7 ETM+ to estimate species diversity in the Zagros forests, digital data related to the August 7, 2002 from forests in the Qalajeh Kermanshah Province were ...
The use of remote sensing techniques as a suitable solution to estimate the levels of species diversity is of high importance for the sustainable management of forests. In order to investigate the potential of using sensor data from Landsat 7 ETM+ to estimate species diversity in the Zagros forests, digital data related to the August 7, 2002 from forests in the Qalajeh Kermanshah Province were ...
A field survey was conducted in Wukari, Taraba State to assess the diversity and abundance of insect species in selected habitats (residential, open field made up of grassland and an agroecosystem). Sampling were done biweekly using light, pitfall and yellow pan traps set in 3 replicates, 30 m apart. Insects recovered were wet preserved in 70% ethanol except butterflies and moths. Representativ...
Selection of genotypes based on high value of heritability and forecasted genetic conditions would be an effective method for improvement of wheat cultivars. The present investigation was carried out to estimate the genetic variability of agro-physiological characters using biometrical genetic techniques in 20 bread wheat genotypes under irrigated condition. For this purpose an experiment was c...
biodiversity refers to all forms of living animals, plants and microorganisms and agro-biodiversity is a component of biodiversity that represents diversity in arable lands. the aim of this study was to determine the biodiversity status of agro-ecosystems of shahr-e-rey city located in south of tehran, through calculating species richness index using rarefaction method. to the collect required ...
Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM), Michoacán, Mexico, and related it to local (site-level) habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice ...
the gobies are non-commercial fishes in the iranian waters of the caspian sea for which population dynamics and stock status are poorly known. in this survey, we tried to define species diversity and catch per unit effort (cpue) of gobiidae by using beach seine nets in salmanshahr, the southern caspian sea. from march 2011 to april 2012, 224 specimens representing 4 gobiid species, belonging to...
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