نتایج جستجو برای: arid regions in each studied system

تعداد نتایج: 17364255  

Journal: :مرتع و آبخیزداری 0
فریبا علوی زاده دانشجوی کارشناسی ارشد مرتع داری، دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد کمال الدین ناصری استادیار دانشکدة منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد علی گلکاریان استادیار دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد علی طویلی دانشیار دانشکده منابع طبیعی، دانشگاه تهران

soil erosion is a main hazard in most area of the country specially in arid and semi-arid regions and itis very important because of sedimentation, pollution, increased flooding and its negative effects onsoil productivity. one of the features of arid and semi-arid areas is the presence of low cover ofvascular plants. these empty spaces are usually good niches for biological soil crusts or cryp...

ارسنگ جنگ, شهرام, حیدری, حمیدرضا, شمسی پور, علی اکبر, گلبابایی, فریده,

Introduction: Regarding development of several thermal indices and limitations of each, in this research applicability and validity of temperature- humidity index (Humidex) were examined against the standard heat index, Wet Bulb Globe Temperature -WBGT, as well as tympanic temperature of subjects. Material and Method:  This cross-sectional study was done on 163 subjects at spring and summer ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه مازندران 1388

some researches made in the field of agency problem issue, deal with the role of control systems regarding owners and managers. in this research the relationship between the two control mechanisms, namely the voluntary disclosure (external control mechanism) and outside directors (internal control mechanism), which are reductive of agency problems, has been studied. for this reason, a sample ...

Journal: :بوم شناسی کشاورزی 0
سروناز فرهنگ فر جعفر کامبوزیا رضا دیهیم فرد سعید صوفی زاده بابک میرباقری

isfahan province is located in the center of iran and has arid and semi-arid climate. in recent years, water shortage has increased in this region and has affected crop production. wheat is one of the most important crops of the province. in the present research, an index (dei) has been developed for drought evaluation using long term climatic data through application of principle components an...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده برق و کامپیوتر 1391

in the area of automotive engineering there is a tendency to more electrification of power train. in this work control of an induction machine for the application of electric vehicle is investigated. through the changing operating point of the machine, adapting the rotor magnetization current seems to be useful to increase the machines efficiency. in the literature there are many approaches wh...

Journal: :Journal of the Japanese Society of Revegetation Technology 1992

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1372

a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز 1390

building on previous studies on the effectiveness of different types of written corrective feedback, the present study aimed at investigating whether direct focused corrective feedback and direct unfocused corrective feedback produced any differential effects on the accurate use of english articles by efl learners across two different proficiency levels (low and high). in current study, the par...

Journal: :journal of rangeland science 2013
gholamreza zehtabian hossein azarnivand hasan ahmadi saeideh kalantari

one of the influential tools concerning the rangeland and vegetation sciences isthe technology of remote sensing and satellite data. satellite data have played essentialroles in preparing the needed information for studying the vegetation. vegetation has beenwidely recognized as one of the best indicators for determining the land conditions. usingvegetation indices is one of the techniques of r...

2012
Kiyotsugu YODA Mohamed Abd ELBASIT Buho HOSHINO Hiroshi NAWATA Hiroshi YASUDA

Prosopis juliflora (Swartz) DC is one of the most economically and/or ecologically important legumes in arid and semi-arid regions of the world. Prosopis was introduced into Sudan in early 20 century, and succeeded in controlling the expansion of desert in northern Sudan. Recently, however, this species distributes widely and rapidly in eastern Sudan, and induces many problems in human subsiste...

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