نتایج جستجو برای: create ecosystem balance in these large patches

تعداد نتایج: 17173839  

Journal: :محیط شناسی 0
طاهره کوخائی کارشناسی ارشد مهندسی طراحی محیط زیست، دانشکدۀ محیط زیست، دانشگاه تهران محمدرضا مثنوی دانشیار گروه مهندسی طراحی محیط زیست، دانشکدۀ محیط زیست، دانشگاه تهران

introduction the urban population experienced rapid growth in the recent decades, particularly between 1975 and 2000 when it has reached from 1.5 to more than 2 billion people. by turn of the century; half of the world's populations are concentrated in cities. this would severely affect the quality of life in urban areas. accordingly, cities will be faced with significant challenges in inf...

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

a one dimensional dynamic model for a riser reactor in a fluidized bed catalytic cracking unit (fccu) for gasoil feed has been developed in two distinct conditions, one for industrial fccu and another for fccu using various frequencies of microwave energy spaced at the height of the riser reactor (fccu-mw). in addition, in order to increase the accuracy of component and bulk diffusion, instanta...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2014
Filippo Botta Namiko Mitarai

The effect of disturbance on a model ecosystem of sessile and mutually competitive species [Mathiesen et al., Phys. Rev. Lett. 107, 188101 (2011); Mitarai et al., Phys. Rev. E 86, 011929 (2012)] is studied. The disturbance stochastically removes individuals from the system, and the created empty sites are recolonized by neighboring species. We show that the stable high-diversity state, maintain...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و 1387

we show that when both sources ( lepton flavor violation sources and cp-violating phases) are present, the electric dipole moment of the electron, $d_e$, receives a contribution from the phase of the trilinear $a$-term of staus, $phi_{a_ au}$. for $phi_{a_ au}=pi/2$, the value of $d_e$, depending on the ratios of the lfv mass elements, can range between zero and three orders of magnitude a...

2013
Hamid Siroosi Gholam Ali Heshmati Abdolrassoul Salman Mahini Hamid Reza Naseri

Preservation of ecosystems requires an understanding of the ecosystem processes that regulate ecosystem resources. Patches and inter-patch features are parts of the ecosystem that are partially responsible for effects on transporting and storing materials in the ecosystem. The structural features of ecological patches including size, number and the average inter-patch length are important becau...

Journal: :تحقیقات جغرافیایی 0
محمدرضا نقوی گروه جغرافیا، دانشگاه تربیت مدرس عبدارضا رکن الدین افتخاری گروه جغرافیا، دانشگاه تربیت مدرس مهدی پورطاهری گروه جغرافیا، دانشگاه تربیت مدرس

rapid population increase, expanding urbanization, lack of employment opportunities, particularly in agriculture, population pressure on natural resources and failing to create and expand medium and large industries, especially in developing countries led industrialization strategy that these countries from the mid-decade villages 1970 in their development programs to consider. this year emphas...

1- INTRODUCTION Over the past few decades, the objective of the evaluation and monitoring of the optimal utilization of sustainable natural resource services and ecosystem performance has been the successor to the ecosystem structure. Tongway and Hindley introduced a Landscape Function Analysis (LFA) method in 2004 to evaluate the ecosystem Function. In the new method, soil is considered as th...

The arid zone encompasses land that has an imbalance between precipitation and losses through evaporation. Globally, arid zones comprise large part of many countries in the mid-latitudes in both the Northern and the Southern hemispheres. Both Australia and Iran are countries with a large arid zone. This negative water balance in the arid zone affects the type of land use in these countries. At ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده جنگلداری و مهندسی چوب و کاغذ 1391

درک الگوی توزیع مکانی ماکروفون خاک بدلیل اثرات آن روی فرآیندهای اکوسیستم بسیار مهم است. لیکن اطلاعات کمی در این خصوص وجود دارد. درمورد تنوع زیستی ارگانیسم ها وجانداران خاکزی که ازاجزای مهم وکلیدی درهرسیستم اکولوژیکی هستند و در بهبود حاصلخیزی خاک و تولیدات زمین وپایداری اکوسیستم ها(ازطریق فرآیندهای بیولوژیک)نقش عمده دارند تحقیقات کمی انجام شده است. این تحقیق جهت بررسی الگوی مکانی پارامترهای تنوع...

2015
CARMEN G. MONTAÑA CRAIG A. LAYMAN KIRK O. WINEMILLER

The curvilinear relationship between species richness and habitat area (species–area relationship (SAR)) is a fundamental ecological pattern. The relationship is often viewed from a long-term perspective across relatively large spatial scales, reflecting a balance between immigration and extinction dynamics. We explored whether predictions of SAR also manifest over short time periods (days) in ...

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