نتایج جستجو برای: diversity indices

تعداد نتایج: 268614  

Journal: :مرتع و آبخیزداری 0
جواد معتمدی (ترکان) استادیار گروه مرتع و آبخیزداری، دانشکده منابع طبیعی دانشگاه ارومیه اسماعیل شیدای کرکج دانشجوی دکتری علوم مرتع دانشگاه علوم کشاورزی و منابع طبیعی گرگان

species diversity is one of the important characteristics shows rangeland ecosystems changes, which isalready under effects of management practices. thus, this research was conducted to study speciesdiversity variation and assess suitable distributive abundance model in three rangeland sites in westazerbaijan. these sites were almost similar in environmental properties and differ in view point ...

2009
Danielle S. McNamara Scott A. Crossley Philip M. McCarthy

In this study, a corpus of expert-graded essays, based on a standardized scoring rubric, is computationally evaluated so as to distinguish the differences between those essays that were rated as high and those rated as low. The automated tool, Coh-Metrix, is used to examine the degree to which highand lowproficiency essays can be predicted by linguistic indices of cohesion (i.e., coreference an...

ژورنال: علوم آب و خاک 2009
راهداری, وحید, سفیانیان, علیرضا, ملکی نجف ابادی, سعیده,

Landscape ecology as a modern interdisciplinary science offers new concepts, theories, and methods for land evaluation and management. One main part of landscape ecology is describing patterns in the landscape and interpreting the ecological effects of these patterns on flora, fauna, flow of energy and materials. Landscape studies require methods to identify and quantify spatial patterns of lan...

Determination of factors affecting on species distribution and diversity, especially in desert areas is the most important factor in rangeland ecosystems management for encountering biological stress. In order to evaluate the effect of physiographic factors on plant biodiversity in natural ecosystems of Kakhk Gonabad, this research was conducted in spring 2014. First, by overlaying four maps of...

A.R. Mirzajani, B. Kiabi S.A. Nezami

In the present study, some ecological factors were studied for Amphipoda at different depths. The Shannon, Margalef, and Hill indices were used to determine the  species diversity, richness and evenness, respectively. In addition, the association and niche overlap values were estimated. Indices of species richness and diversity were highest at 50 and 100m depths, respectively.  The ordination o...

Journal: :Int. J. Communication Systems 2016
Ying-Dar Lin Yuan-Cheng Lai Chun-Nan Lu Jui-Tsun Hung Chun-Pin Shao

It is generally assumed that using more diverse traffic to test network devices could achieve larger code coverage. However, how to describe the diversity of traffic traces and the relationship between the traffic diversity and code coverage is still an issue. In this paper, the traffic diversity is defined using the number of packets and the size of the subnets involved, and traces having vari...

2015
A. Gasc S. Pavoine L. Lellouch P. Grandcolas J. Sueur

a r t i c l e i n f o Rapid acoustic surveys aim to estimate biodiversity based on the diversity of sounds produced by animal communities , and interest in this approach among conservation planners is increasing. Several indices of acoustic diversity have been proposed as proxies for species richness. However, in the field, the animal activity may be responsible for acoustic diversity to varyin...

Journal: :The Journal of trauma 2003
David G Jacobs Brian Ray Plaisier Philip S Barie Jeffrey S Hammond Michele R Holevar Karlene E Sinclair Thomas M Scalea Wendy Wahl

Journal: :Revista de biologia tropical 2009
Gilbert Barrantes Luis Sandoval

Diversity indices, particularly the Shannon-Wiener index, have extensively been used in analyzing patterns of diversity at different geographic and ecological scales. These indices have serious conceptual and statistical problems which make comparisons of species richness or species abundances across communities nearly impossible. There is often no a single statistical method that retains all i...

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