نتایج جستجو برای: diversity indices

تعداد نتایج: 268614  

ژورنال: علوم آب و خاک 2019

Landscapes are considered as a series of different land units with a size, shape and location arrangement that are permanently under the influence of natural events and human activities. Understanding the dynamics and heterogeneity of landscapes and environmental changes is of great importance. In order to quantitatively analyze and interpret the factors affecting the changes in the environment...

Journal: :جنگل و فرآورده های چوب 0
سمیه کرمی راد دانشگاه تهران احسان عبدی دانشکده منابع طبیعی باریس مجنونیان دانشگاه تهران وحید اعتماد دانشگاه تهران هرمز سهرابی دانشگاه تربیت مدرس

road construction is one of the effective factors for ecological changes which affects diversity and species composition in forest roads edges. this research was performed in kheirud forest to evaluate herbaceous diversity and tree regeneration establishment in different distances from road edge. for this purpose, we sampled herbaceous and tree species regeneration in 0,5,10,25, 50 and 100 m di...

2017
Michael Grabchak Eric Marcon Gabriel Lang Zhiyi Zhang

Modern measures of diversity satisfy reasonable axioms, are parameterized to produce diversity profiles, can be expressed as an effective number of species to simplify their interpretation, and come with estimators that allow one to apply them to real-world data. We introduce the generalized Simpson's entropy as a measure of diversity and investigate its properties. We show that it has many use...

Journal: :Genetics and molecular research : GMR 2015
I Z Backouchi M Aouida N Khemiri M Jebara

Genetic diversity within Vicia faba L. is key to the genetic improvement of this important species. In this study, morphological traits and RAPD molecular markers were used to assess the levels of polymorphism across 12 Tunisian populations, three major and nine minor from different locations. Analysis of morphological traits indicated that the three major populations showed significant differe...

2012
Ellen Karla Nobrex da Costa da Santos Rubens Tomio Honda Sérgio Ricardo Nozawa Monica Stropa Ferreira-Nozawa

Analysis of bacterial diversity in soils along the banks of the Solimões and Negro rivers, state of Amazonas, Brazil, was by partial sequencing of the genes codifying the rDNA16S region. Diversity of operational taxonomic units (OTU) and of the divergent sequences obtained were applied in comparative analysis of microbiological diversity in the two environments, based on richness estimators and...

Journal: :Behavior research methods 2013
Danielle S McNamara Scott A Crossley Rod Roscoe

The Writing Pal is an intelligent tutoring system that provides writing strategy training. A large part of its artificial intelligence resides in the natural language processing algorithms to assess essay quality and guide feedback to students. Because writing is often highly nuanced and subjective, the development of these algorithms must consider a broad array of linguistic, rhetorical, and c...

2015
Shelly K. Aust Dakota L. Ahrendsen P. Roxanne Kellar

BACKGROUND Conservation of the evolutionary diversity among organisms should be included in the selection of priority regions for preservation of Earth's biodiversity. Traditionally, biodiversity has been determined from an assessment of species richness (S), abundance, evenness, rarity, etc. of organisms but not from variation in species' evolutionary histories. Phylogenetic diversity (PD) mea...

Journal: :Trees-structure and Function 2021

Key messageThe use of structural diversity indices can be efficient tools to increase understanding changes in soil carbon storage as a key ecosystem function along the oak dieback intensity.Investigating relationships between biodiversity and functions within mass‐ratio niche complementary hypotheses is still challenging issue terrestrial ecology. These have not been studied gradient disturban...

Journal: :Haematologica 2001
E S Ma A Y Chan S Y Ha Y L Lau L C Chan

2014
Ramón Silva-Flores Gustavo Pérez-Verdín Christian Wehenkel

Biological diversity can be defined as variability among living organisms from all sources, including terrestrial organisms, marine and other aquatic ecosystems, and the ecological complexes which they are part of. This includes diversity within species, between species, and of ecosystems. Numerous diversity indices combine richness and evenness in a single expression, and several climate-based...

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