نتایج جستجو برای: patch area index

تعداد نتایج: 981082  

2003
David M. Watson

Studies of habitat fragmentation have been restricted primarily to anthropogenically-altered habitats, with most research conducted 60–90 years post-fragmentation. It is unclear whether patterns in older systems concur with results from these dynamic landscapes, and hence the long-term viability of populations inhabiting habitat fragments remains largely unexplored. I focused on resident birds ...

Journal: :محیط زیست طبیعی 0
مونا اسماعیل پور دانشجوی کارشناسی ارشد محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران محمد کابلی گروه محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران محمود کرمی گروه محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران افشین علیزاده شعبانی گروه محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران آزیتا فراشی گروه محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه فردوسی مشهد، مشهد، ایران

increasing patch edges in natural habitats, as a result of habitat fragmentation, are a major threat for wildlife populations, especially avifaunal communities. habitat edges provide different conditions compared to the core area which can directly or indirectly cause changes in species number, population and composition. this fact will demand a dissimilar management strategy. this study was co...

A Ekhlasi A.R Fekri F Darvish Damavandi I Esfandiarpour S Farajzadeh S Saryazdi S Shamsadini S Zandi S. Shamsi Meimandi Z Daraie Z Rahnama

Introduction: Allergic and irritant compounds are frequent in nature, and the environmental allergic factors which can induce or exacerbate eczema are different and often unknown in different areas. The aim of this study was to determine the frequency of contact dermatitis in patients with chronic dermatitis referring to dermatology clinics in kerman. Methods: In this descriptive study, standar...

2005
Mexico Stephens

Question: What are the shape, abundance, size, and structural characteristics of sapling patches in an old-growth Pinus jeffreyi-mixed conifer forest with a relatively intact disturbance regime? Location: Sierra San Pedro Martir, Baja California, Mexico. Methods: Regeneration was quantified by sampling sapling patches on seven 1200 m permanently marked line transects. For all patches intersecte...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Laura R Prugh Karen E Hodges Anthony R E Sinclair Justin S Brashares

Habitat destruction has driven many once-contiguous animal populations into remnant patches of varying size and isolation. The underlying framework for the conservation of fragmented populations is founded on the principles of island biogeography, wherein the probability of species occurrence in habitat patches varies as a function of patch size and isolation. Despite decades of research, the g...

Journal: :IEICE Transactions 2011
Uisheon Kim Jaehoon Choi

This paper proposes a microstrip patch antenna for 2.45 GHz Industrial Scientific Medical (ISM) band Wireless Body Area Network (WBAN) applications. To enhance the front-to-back ratio (F/B) and specific absorption rate (SAR), an electrically coupled LC resonator is introduced. The overall dimensions of the proposed antenna are 54 mm × 45 mm × 2.4 mm and it has a gain of over 1 dBi for the entir...

Journal: :Science 2007
Gonçalo Ferraz James D Nichols James E Hines Philip C Stouffer Richard O Bierregaard Thomas E Lovejoy

As compared with extensive contiguous areas, small isolated habitat patches lack many species. Some species disappear after isolation; others are rarely found in any small patch, regardless of isolation. We used a 13-year data set of bird captures from a large landscape-manipulation experiment in a Brazilian Amazon forest to model the extinction-colonization dynamics of 55 species and tested ba...

2008
Kenny S. Ryu

A new design of a wideband dually-polarized shorted microstrip patch antenna coupled to hook shaped probes is presented. The antenna is designed to operate around 4 GHz. The mechanisms of the shorted microstrip patch antenna provide wider impedance bandwidth over 37%. The shorted patch is smaller than as with to the unshorted patch. The present design provides about 40 dB isolation level betwee...

Journal: :Social Science Research Network 2022

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