نتایج جستجو برای: briloen dispersal

تعداد نتایج: 19935  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم پایه 1393

مطالعه و بحث در مورد انواع لیزر در چند دهه اخیر، یکی از شاخه های مهم در کاربرد علم فیزیک بوده است. در این پایان نامه به بررسی لیزرهای فیبری بریلوئن آغشته به اربیوم پرداخته شدهداست. فرآیند فیزیکی پراکندگی بریلوئن به وسیله برهمکنش غیر خطی بین نور و محیط پراکنده ایجاد می شود که ریشه در پدیده ای به نام کشیدگی الکتریکی دارد.پراکندگی بریلوئن به عنوان یک پدیده اپتیک غیر خطی ، کاربردهای زیادی به شکل تق...

2014
Stephan Getzin Thorsten Wiegand Stephen P. Hubbell

The spatial placement of recruits around adult conspecifics represents the accumulated outcome of several pattern-forming processes and mechanisms such as primary and secondary seed dispersal, habitat associations or Janzen-Connell effects. Studying the adult-recruit relationship should therefore allow the derivation of specific hypotheses on the processes shaping population and community dynam...

Long-term survival of Goitered gazelles in central Iran has been threatened because of isolation of existing populations and genetic threats. Effective management of these small and isolated populations needs to evaluate landscape connectivity among core habitat patches. In the present study, resistance surfaces were mapped as a function of twelve uncorrelated variables using species distributi...

2009
Benjamin Chi Wang Victoria L. Sork Thomas W. Gillespie Thomas B. Smith Shirley Wang

O F T H E DISSERTATION Impacts of hunting on seed dispersal in a Central African tropical forest

2017
András Kelemen Béla Tóthmérész Orsolya Valkó Tamás Miglécz Balázs Deák Péter Török

Classical old-field succession studies focused on vegetation changes after the abandonment of annual croplands or on succession after the elimination of cultivated crops. Perennial-crop-mediated succession, where fields are initially covered by perennial crops, reveals alternative aspects of old-field succession theories. We tested the validity of classical theories of old-field succession for ...

Journal: :Ecology letters 2017
Eugene W Schupp Pedro Jordano José María Gómez

A core interest in studies of mutualistic interactions is the 'effectiveness' of mutualists in providing benefits to their partners. In plant-animal mutualisms it is widely accepted that the total effect of a mutualist on its partner is estimated as (1) a 'quantity' component multiplied by (2) a 'quality' component, although the meanings of 'effectiveness,' 'quantity,' and 'quality' and which t...

Journal: :The American naturalist 1997
B Shipley

In this article, I first describe some recent developments in the identification of the structure of dependencies among variables in multivariate data relevant to exploratory path analysis. I then introduce a bootstrap modification of one important method (the SGS algorithm) that is designed to improve error rates of exploratory path analysis in the small data sets that are typical of studies i...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Elizabeth M Wandrag Amy E Dunham Richard P Duncan Haldre S Rogers

Dispersal is thought to be a key process underlying the high spatial diversity of tropical forests. Just how important dispersal is in structuring plant communities is nevertheless an open question because it is very difficult to isolate dispersal from other processes, and thereby measure its effect. Using a unique situation, the loss of vertebrate seed dispersers on the island of Guam and thei...

Journal: :Evolution; international journal of organic evolution 1998
John R Pannell Spencer C H Barrett

Baker's Law states that it is more likely for self-compatible than for self-incompatible individuals to establish sexually reproducing colonies after long-distance dispersal, because only the former can do so with a single individual. This hypothesis, proposed by H. G. Baker 40 years ago is based largely on the observation that self-compatibility is particularly frequent among colonists of ocea...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید