Results 251 to 260 of about 8,857,554 (290)
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Null Models for the Opportunity for Selection
The American Naturalist, 2022Abstract Crow’s ‘Opportunity for Selection’ ( I =variance in relative fitness) is an important albeit controversial eco-evolutionary concept, particularly regarding the most appropriate null model(s).
Robin S, Waples, Thomas E, Reed
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Null models in network neuroscience
Nature Reviews Neuroscience, 2022Recent advances in imaging and tracing technology provide increasingly detailed reconstructions of brain connectomes. Concomitant analytic advances enable rigorous identification and quantification of functionally important features of brain network architecture.
František Váša, Bratislav Mišić
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Null models for null hypotheses in taxonomy: a test using Scyphozoa
Biological Journal of the Linnean Society, 2021Abstract Although molecular tools are becoming more important in the delineation of scyphozoan species there is, perforce, a need to substantiate new species definitions using morphological data. Access to type material is often difficult and detailed, raw morphometric data are rarely provided in older type descriptions, which makes ...
Michael K Brown, Mark J Gibbons
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Comments on Wilson's Null Model
Oecologia, 1987We agree with several of Wilson's general observations concerning the difficulties and pitfalls of this approach to distributional ecology. We disagree on two of his main points, however. First, he has not correctly discussed our own procedure. Second, the model he has produced contains a serious flaw. Related to this second point, we find his analysis
M E, Gilpin, J M, Diamond
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A Null Model of Morphospace Occupation
The American Naturalist, 2005Progress in understanding the relationship between lineage diversity, morphological diversity, and morphospace dynamics has been hampered by the lack of an appropriate null model of morphospace occupation. In this article, we introduce a simple class of models based on branching random walks (BRWs) for continuous traits.
Pie, Marcio R., Weitz, Joshua S.
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Annual Review of Ecology and Systematics, 1983
What determines the particular combinations of species found in biological communities, the number of those species, and their relative abundance? These questions are of perennial interest to ecologists, who often cite the influence of various factors-competition, predation, climate, nutrient availability, and chance dispersal events, to name a few ...
P H Harvey +3 more
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What determines the particular combinations of species found in biological communities, the number of those species, and their relative abundance? These questions are of perennial interest to ecologists, who often cite the influence of various factors-competition, predation, climate, nutrient availability, and chance dispersal events, to name a few ...
P H Harvey +3 more
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Influence of the Null-Model on Motif Detection
Proceedings of the 2015 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining 2015, 2015This paper focuses on the suitability of three different null-models to motif analysis that all get as an input a desired degree sequence. A graph theoretic null-model is defined as a set of graphs together with a probability function. Here we discuss the configuration model, as the simplest model; a variant of the configuration model where multi-edges
Wolfgang E. Schlauch +3 more
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A Note on Null Models: Justifying the Methodology
Ecology, 2002The use of random, or null, models to determine whether species co-occurrences differ from chance expectations is an established technique in community ecology. Several methods have been used to draw conclusions regarding species co-occurrence patterns. We compared a sequential method derived previously with a recently proposed new method.
Bryan Manly, James G. Sanderson
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Faddeev null-plane model of the nucleon
Physical Review C, 1995The nucleon is formulated as a relativistic system of three constituent quarks interacting via a zero-range two-body force in the null plane. The covariance of the null-plane Faddeev-like equation under kinematical front-form boosts is discussed. The nucleon wave function is obtained from the numerical solution of the Faddeev equation in the null plane.
, de Araújo WR +2 more
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THE SCHWINGER MODEL ON THE NULL-PLANE
International Journal of Modern Physics E, 2007We study the Schwinger Model on the null-plane using the Dirac method for constrained systems. The fermion field is analyzed using the natural null-plane projections coming from the γ-algebra and it is shown that the fermionic sector of the Schwinger Model has only second class constraints.
Casana, R. +2 more
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