Estimating the Diets of Animals Using Stable Isotopes and a Comprehensive Bayesian Mixing Model

Using stable isotope mixing models (SIMMs) as a tool to investigate the foraging ecology of animals is gaining popularity among researchers. As a result, statistical methods are rapidly evolving and numerous models have been produced to estimate the diets of animals—each with their benefits and their limitations. Deciding which SIMM to use is contingent on factors such as the consumer of interest, its food sources, sample size, the familiarity a user has with a particular framework for statistical analysis, or the level of inference the researcher desires to make (e.g., population- or individual-level). In this paper, we provide a review of commonly used SIMM models and describe a comprehensive SIMM that includes all features commonly used in SIMM analysis and two new features. We used data collected in Yosemite National Park to demonstrate IsotopeR's ability to estimate dietary parameters. We then examined the importance of each feature in the model and compared our results to inferences from commonly used SIMMs. IsotopeR's user interface (in R) will provide researchers a user-friendly tool for SIMM analysis. The model is also applicable for use in paleontology, archaeology, and forensic studies as well as estimating pollution inputs

Treating gliomas with glucocorticoids: from bedside to bench

Glucocorticoids are used in the treatment of gliomas to decrease tumour-associated oedema and to reduce the risk of acute encephalopathy associated with radiotherapy. However, the mechanisms by which glucocorticoids work are still largely unknown. In this paper, we survey the experimental and clinical evidence for the effects of glucocorticoids on tumour cell proliferation, apoptosis and sensitivity to chemotherapy, angiogenesis and vascular permeability. We then review current guidelines on the choice of molecule, dose and duration of glucocorticoid treatment for gliomas

Interpersonal and Affective Psychopathy Traits Can Enhance Human Fitness

Recently, attempts have been made to determine the evolutionary status of psychopathy. However, there is still a gap in empirical literature regarding the connection between psychopathy and fitness. In the present study, we explored the relations between the four-factor model of psychopathy and reproductive success as a fitness indicator in a sample of male convicts (N = 181). Direct relations were analyzed, together with the interaction effects between psychopathy and family risk factors (presence of criminality, substance abuse, and maltreatment in participants’ families). Basic regression models showed that the facet of interpersonal style is positively related to fitness, while other psychopathic characteristics had a negative connection with the criterion measure. Additionally, we found three significant interactions, which further clarified the relation between psychopathy and reproductive success. One of the interactions showed that affective traits can facilitate fertility in unfavorable environmental conditions. Results support a hypothesis of a possible adaptive function of psychopathy, broaden the concept of “successful psychopathy,” and confirm a view of psychopathy as a heterogeneous and complex construct, consisting of facets with distinct content