نتایج جستجو برای: evaluation of diversity
تعداد نتایج: 21212557 فیلتر نتایج به سال:
This document explains diversity related methods in vegan. The methods are briefly described, and the equations used them are given often in more detail than in their help pages. The methods discussed include common diversity indices and rarefaction, families of diversity indices, species abundance models, species accumulation models and beta diversity, extrapolated richness and probability of ...
in order to study genetic diversity of aegilops tauschii populations, 188 populations of national plant gene bank collection of iran were evaluated for morphological traits according to ipgri descriptors in research station of national plant gene bank. moreover, 100 out of 188 populations were evaluated in research station of seed and plant improvement institute for resistance to yellow rust, p...
asymptomatic malaria (asm) has been implicated in the development of hemolytic crisis in infected sickle cell anemia (sca) patients worldwide. this study surveyed steady state sca nigerian patients for asm to investigate the influence of malaria prevention behaviors and age on parasitaemia and multiplicity of infection (moi). a total of 78 steady sca patients aged 5 – 27 years on routine care a...
Traditional information retrieval (IR) systems mostly focus on finding documents relevant to queries without considering other documents in the search results. This approach works quite well in general cases; however, this also means that the set of returned documents in a result list can be very similar to each other. This can be an undesired system property from a user’s perspective. The crea...
Habitat distribution and seasonal occurrence of carabid beetles were determined using pitfall traps in 1999 and 2000 in the temperate forest zone of the Dongling Mountain, North China. Eight sites differing in vegetation and moisture were selected so as to represent four habitat types. Carabid assemblages of the six forested habitats (lowland, upland and coppice) were more similar to each other...
This paper presents a geomorphological map of the Hérens valley in the Western Swiss Alps. With an area of 270 km and altitudes ranging from 470 to 4357 m a.s.l., this valley is one of the main secondary catchments of the Upper Rhône valley. The high differences in altitudes, combined with a varied geology, create an important geomorphic diversity. The main processes active in mountain areas, t...
As troves of microbiome sequencing data provide improved resolution of patterns of microbial diversity, new approaches are needed to understand what controls these patterns. Many microbial ecologists are using cultivated model microbial communities to address this challenge. These systems provide opportunities to identify drivers of microbiome assembly, but key challenges and limitations need t...
مراتع حدود نیمی از خشکی های جهان را در بر دارند و پوشش گیاهی آن در نتیجه تأثیر متقابل محیط و موجودات زنده به وجود آمده است و به عنوان یک اکوسیستم طبیعی مدیریت می شوند. علاوه بر مراتع، راه ها در عصر حاضر نیز از اجزا مهم و زیرساخت های اصلی زندگی نوین و توسعه کشورها به شمار می روند. جاده ها ساخته دست بشر هستند و جوامع گیاهی کنار جاده تحت تأثیر ساخت و ساز قرار دارند. پوشش "رودرال" به مجموعه ای از پ...
Evaluation measures play a vital role in analyzing the performance of a system, comparing two or more systems, and optimizing systems to perform some task. In this paper, we analyze and highlight the strengths and weaknesses of commonly used measures for evaluating the diversity in search results. We compare MAP-IA, α-nDCG, and ERR-IA using data from TREC’09 web track diversity runs and simulat...
Contents 1. Introduction – biodiversity in agricultural ecosystems 2. Planned diversity and the functioning of agricultural systems 2.1. Intraspecific diversity 2.2. Species diversity 2.3. Habitat and landscape diversity 3. Unplanned diversity and the functioning of agricultural systems. 3.1. Pollination services 3.2. Soil processes 3.3. Natural pest control 4. Conclusions Bibliography Biograph...
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