نتایج جستجو برای: diversity index

تعداد نتایج: 577656  

Journal: :تحقیقات مالی 0
سعید فلاح پور استادیار، گروه مالی و بیمه، دانشکدة مدیریت، دانشگاه تهران، تهران، ایران فرید تندنویس دانشجوی کارشناسی ارشد مهندسی مالی، دانشکدة مدیریت، دانشگاه تهران، تهران، ایران

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...

Journal: :محیط زیست طبیعی 0
علی رضا میرزاجانی عضو هیئت علمی مؤسسۀ تحقیقات علوم شیلاتی کشور ـ پژوهشکدۀ آبزی پروری آب های داخلی (بندر انزلی) احمد قانع عضو هیئت علمی مؤسسۀ تحقیقات علوم شیلاتی کشور ـ پژوهشکدۀ آبزی پروری آب های داخلی (بندر انزلی) سید حجت خداپرست عضو هیئت علمی مؤسسۀ تحقیقات علوم شیلاتی کشور ـ پژوهشکدۀ آبزی پروری آب های داخلی (بندر انزلی) سیدقاسم قربانزاده زعفرانی گروه اکولوژی دریا ـ معاونت محیط زیست دریایی سازمان حفاظت محیط زیست امید صدیقی سوادکوهی گروه اکولوژی دریا ـ معاونت محیط زیست دریایی سازمان حفاظت محیط زیست

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...

Journal: :آب و خاک 0
شایسته غلامی سید محسن حسینی جهانگرد محمدی عبدالرسول سلمان ماهینی

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...

Rohollah Parma, Shaban Shataee

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 ...

Rohollah Parma, Shaban Shataee

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 ...

Emmanuel Okrikata, Olajumoke Anuoluwa Yusuf,

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...

Akbar Shabani Ezatollah Farshadfar, Hossein Romena

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...

Journal: :بوم شناسی کشاورزی 0
آرش قلعه گلاب بهبهانی مهدی نصیری محلاتی رضا کشاورز افشار علی علی پور جهانگیری علیرضا پازکی حسام صفا محمد کریمی نژاد

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 ...

Journal: :Revista de biologia tropical 2011
José Antonio Gómez-Anaya Rodolfo Novelo-Gutiérrez William Bruce Campbell

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 ...

Journal: :iranian journal of fisheries science 0
s.m. kalantarian a. abdoli b.h. kiabi

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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