نتایج جستجو برای: 68 and 32 percent of species were annual and perennial weeds

تعداد نتایج: 24113261  

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

during 2010-2011 a faunistic survey was carried out for collection and identification of edaphic mesostigmatic mites (acari: mesostigmata) in jiroft and suburb. mites were extracted from soil samples by berlese funnel. the mites were cleared in nesbit fluid and were mounted in hoyer medium on microscopic slides. in this study 43 spices from 26 genera and 16 families were collected and identifie...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده مدیریت 1392

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه لرستان - دانشکده علوم پایه 1389

abstract part one: the electrode oxidation potentials of a series of eighteen n-hydroxy compounds in aqueous solution were calculated based on a proper thermodynamic cycle. the dft method at the level of b3lyp-6-31g(d,p) was used to calculate the gas-phase free energy differences ,and the polarizable continuum model (pcm) was applied to describe the solvent and its interaction with n-hydroxy ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده فنی 1393

asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده زیست شناسی 1388

126 abstract: in this research we studied the effects of cyclic hydration and dehydration of cysts of artemia urmiana and artemia parthenogenetica on the hatching percentage, survival and growth. the experiment was carried out in 3 treatments (1-3 hydration/dehydration cycles) with 3 replicates for each treatment. later effects of cold preservation at -20°c during three time periods were ...

پایان نامه :0 1374

the rationale behind the present study is that particular learning strategies produce more effective results when applied together. the present study tried to investigate the efficiency of the semantic-context strategy alone with a technique called, keyword method. to clarify the point, the current study seeked to find answer to the following question: are the keyword and semantic-context metho...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیخ بهایی - دانشکده زبانهای خارجی 1391

phatic communion is a cultural concept which differs across cultures. according to hofstede (2001), the u.s. tends to have individualistic culture; however, asian countries tend to have collectivistic cultures. these cultures view phatic communion differently. in individualistic cultures like u.s., phatic communion reflects speakers’ socio-cultural relationships in conversations. to see whether...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده علوم پایه 1388

introduction acetic acid bacteria are large group of obligate aerobic gram negative bacteria with the ability to oxidize ethanol to acetic acid (1). they are widely distributed in natural habitats and classified in family acetobacteraceae. members of this family are useful in industrial production of vinegar(2). acetic acid bacteria (aab) can use substrates as glucose, ethanol, lactate or glyc...

Journal: :بوم شناسی کشاورزی 0
صغری الهی رضا صدرآبادی حقیقی لیلا علیمرادی

to study weed species diversity and community structure in pistachio (pistacia vera l.) orchards in 33 orchards of 12 villages an investigation was conducted in bardaskan county, khorasan razavi province, iran during 2008-2009. weed population sampling was conducted in a w shape method using 1m² quadrate. the results showed that the weeds of pistachio orchards were belonging to 15 families and ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده منابع طبیعی 1392

nowadays, air pollution is a global problem that has had significant growth by technology development, population growth andindustrial development. industrial development brought natural resources deterioration, more manufacturing products, and more environmental pollutants. if pollutant won’t be controlled, human-being and wildlife will face the critical risks. significant release and critical...

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