Species co-occurrence analysis is commonly used to assess how interspecific interactions dictate community assembly. Non-random co-occurrences, however, may also emerge from niche differences as well as environmental heterogeneity. The relationships between species co-occurrence patterns, environmental heterogeneity and species niches are not fully understood, due to complex interactions among ...

Recent research reports that many populations of species showing a wide trophic niche (generalists) are made up of both generalist individuals and individuals with a narrow trophic niche (specialists), suggesting trophic specializations at an individual level. If true, foraging strategies should be associated with individual quality and fitness. Optimal foraging theory predicts that individuals...

The Asian American, Native Hawaiian, and Pacific Islander population is large, growing, and extremely heterogeneous. Not only do they bear unique burdens of incidence and outcomes for certain cancer types, they exhibit substantial variability in cancer incidence and survival patterns across the ethnic groups. By acknowledging and leveraging this heterogeneity through investing in cancer researc...

Sources of population heterogeneity may or may not be observed. If the sources of heterogeneity are observed (e.g., gender), the sample can be split into groups and the data analyzed with methods for multiple groups. If the sources of population heterogeneity are unobserved, the data can be analyzed with latent class models. Factor mixture models are a combination of latent class and common fac...

the present paper studies the possibility of propagation of torsional surface waves in an inhomogeneous anisotropic layer lying between two heterogeneous half-spaces (upper and lower half-space). both the half-spaces are assumed to be under compressive initial stress. the study reveals that under the assumed conditions, a torsional surface wave propagates in the medium. the dispersion relation ...

aim : in this study, we aimed to estimate one- to five-year survival rates in iranian patients with gastric cancer (gc). in addition, we preformed subgroup analyses and meta-regression to explore possible sources of heterogeneity between studies.   background : according to literatures, there has been increasing attention to the long-term survival rate in patients with gc in iran. however, resu...

A mathematical model is considered to investigate the behavior of horizontally polarized shear waves (SH-waves) in fluid saturated porous medium sandwiched between heterogeneous half-spaces. Heterogeneity in the upper half-space is due to linear variation of elastic parameters, whereas quadratic variation has been considered for lower half-space. The method of separation of variables and Whitta...

Groups do not act as individuals as Olson and other have emphasized: incentives within groups matter. Here we study internal group discipline through a model of costly peer punishment. We investigate schemes that minimize the cost to a collusive group of enforcing particular actions, and use the model to determine how the strength of the group as measured, for example, by ability to raise funds...