نتایج جستجو برای: عوامل اکولوژیک ecological factors

تعداد نتایج: 1274853  

The main purpose of the present study was to assess the ecological capability of agricultural soils using geographic information system (GIS). This research was conducted during 2014 in Hamedan Province, Iran. A cross-sectional study was conducted mapping the 10 factors of soil characteristics (texture, depth, erosion, and aggregation, percentage of slope, direction of slope, height, soil salin...

This study aimed to assess ecological quality status of hard substratum macroinvertebrates communities of the Caspian Sea with three ecological indices and their relation with environmental factors. For this purpose benthic communities of the Caspian Sea basin were studied seasonally during 2014 in 8 sampling sites. Temperature, salinity, dissolved oxygen, pH, nitrate, nitrite, silicate and pho...

Journal: :caspian journal of environmental sciences 2010
arekhi s.

the study was carried out in the ilam oak forest that is located in the west part of iran. the objective of this research was to determine the plant ecological groups and site classification in this region. data were collected from 117 sample plots using the systematic-random sampling method. the size of sampling plots was 20 m?20 m for the tree and shrub species and 1.5 m ?1.5 m for herbaceous...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده کشاورزی 1394

with the increasing population and the need for more food, as well as with the development of science and technology, human approach to unnatural and often chemical inputs to increase agricultural production has been a great expansion and problems such as increased cancers, chronic diseases has created environmental pollution. implementation of organic organic is a solution to these problems . ...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی ایران 1385

چکیده ندارد.

Journal: Addiction and Health 2016
Ali Akbar Haghdoost Farin Kamangar Hamideh Rashidian Kazem Zendehdel Reza Malekzadeh

Background: Cancer is the second leading cause of death after cardiovascular disease. In recent years it has been hypothesized that opiate use could be a risk factor for cancer. This study aimed to evaluate a possible association between opiate use and common cancers using ecological statistics from around the world.Methods: To investigate the association we used ordinary linear regression mode...

ژورنال: :مرتع و آبخیزداری 2012
دیانا عسکریزاده غلامعلی حشمتی

از عوامل مهم تأثیر گذار بر پوشش گیاهی در اکوسیستم‏های مرتعی، فاکتورهای غیر زنده است که نقش مهمی در شکل گیری و توالی انواع پوشش‏های گیاهی دارد. شناخت این عوامل، گام مهمی در مدیریت اکولوژیک مراتع محسوب می‏شود. بدین منظور، مراتع جواهرده رامسر واقع در البرز شمالی از ارتفاع 2000 تا 3200 متر انتخاب شد. با توجه به پایش میدانی و ساختار پوشش گیاهی، طبقات 300 متری برای برداشت داده‏های صحرایی در نظر گرفته...

2008
Suzanne V. Olyarnik Matthew E.S. Bracken Jarrett E. Byrnes A. Randall Hughes Kristin M. Hultgren John J. Stachowicz

What makes a community invasible? For over a century ecologists have sought to understand the relative importance of biotic and abiotic factors that determine community composition. The fact that we are still exploring this topic today hints at both its importance and complexity. As the impacts from harmful non-native species accumulate, it has become increasingly urgent to find answers to the ...

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