Biological Criteria (biological + criterion)

Distribution by Scientific Domains

Selected Abstracts

Modelling habitat selection of Common Cranes Grus grus wintering in Portugal using multiple logistic regression

IBIS, Issue 3 2000
Predictive models of habitat suitability for the Common Crane Grus grus in a wintering area of southern Portugal were derived using logistic multiple regression and Geographic Information Systems. The study area was characterized by landscape variables and surveyed uniformly for the presence of cranes. The most important variables were distance to roosts, to open Holm Oak woods and to villages, and the occurrence of unpaved roads, shrubby vegetation, slope and orchards. Two models were built, the second having one variable fewer than the first. The selection of the best model was based on statistical and biological criteria. Crane distribution was negatively related to: distance to open Holm Oak Quercus rotundifolia woods and roosts. Additionally, unsuitable vegetation and orchard areas are avoided. In these areas movement is difficult, food availability is reduced and the risk of predation increased. We also found that villages and roads were avoided; disturbance is a significant factor for this species. Some management guidelines are proposed for the area: (1) maintenance of open Holm Oak woodlands, (2) incentives to avoid the abandonment of traditional agriculture and pastoral use of the area, which would lead to an increase of shrubby vegetation areas, (3) preservation of suitable roosting places and (4) management of new patches of forest and orchards. [source]

Bioinformatics-based discovery and identification of new biologically active peptides for GPCR deorphanization,

Jean Colette
Abstract Owing to their involvement in many physiological and pathological processes, G-protein-coupled receptors (GPCRs) are interesting targets for drug development. Approximately, 100 endoGPCRs lack their natural ligands and remain orphan (oGPCRs). Consequently, oGPCR deorphanization appears a promising research field for the development of new therapeutics. On the basis of the knowledge of currently known GPCR/ligand couples, some oGPCRs may be targeted by peptides. However, to find new drugs for GPCRs, Genepep has developed a dedicated bioinformatics platform to screen transcriptomic databases for the prediction of new GPCR ligands. The peptide lists generated include specific data, such as chemical and physical properties, the occurrence of post-translational modifications (PTMs) and an annotation referring to the location and expression level of the related putative genes. This information system allows a selection through series of biological criteria of ,10 000 natural peptides including already known GPCR ligands and potential new candidates for GPCR deorphanization. The most promising peptides for functional assay screening and future development as therapeutic agents are under evaluation. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source]


ABSTRACT. We utilize a spatial bioeconomic model to investigate the impacts of creating reserves on limited-entry fisheries. We find that reserve creation can produce win-win situations where aggregate biomass and the common license (lease) price increase. These situations arise in biological systems where dispersal processes are prevalent and the fishery prior to reserve creation is operating at effort levels in a neighborhood of open-access levels. We also illustrate that using strictly biological criteria for siting reserves (e.g., setting aside the most biological productive areas) will likely induce the most vociferous objections from the fishing industry. In general, we find that the dispersal rate and the degree the patches are connected play a significant role on the net impacts on the fishing sector. [source]

Congruence of individual cranial bone morphology and neutral molecular affinity patterns in modern humans

Noreen von Cramon-Taubadel
Abstract Recent studies have demonstrated that the shape of the human temporal bone is particularly strongly correlated with neutral genetic expectation, when compared against other cranial regions, such as the vault, face, and basicranium. In turn, this has led to suggestions that the temporal bone is particularly reliable in analyses of primate phylogeny and human population history. While several reasons have been suggested to explain the temporal bone's strong fit with neutral expectation, the temporal bone has never systematically been compared against other individual cranial bones defined using the same biological criteria. Therefore, it is currently unknown whether the shapes of all cranial bones possess reliable information regarding neutral genetic evolution, or whether the temporal bone is unique in this respect. This study tests the hypothesis that the human temporal bone is more congruent with neutral expectation than six other individual cranial bones by correlating population affinity matrices generated using neutral genetic and 3D craniometric data. The results demonstrate that while the temporal bone shows the absolute strongest correlation with neutral genetic data compared with all other bones, it is not statistically differentiated from the sphenoid, frontal, and parietal bones in this regard. Potential reasons for the temporal bone's consistently strong fit with neutral expectation, such as its overall anatomical complexity and/or its contribution to the architecture of the basicranium, are examined. The results suggest that future phylogenetic and taxonomic studies would benefit from considering the shape of the entire cranium minus those regions that deviate most from neutrality. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source]

Flexible Designs for Genomewide Association Studies

BIOMETRICS, Issue 3 2009
André Scherag
Summary Genomewide association studies attempting to unravel the genetic etiology of complex traits have recently gained attention. Frequently, these studies employ a sequential genotyping strategy: A large panel of markers is examined in a subsample of subjects, and the most promising markers are genotyped in the remaining subjects. In this article, we introduce a novel method for such designs enabling investigators to, for example, modify marker densities and sample proportions while strongly controlling the family-wise type I error rate. Loss of efficiency is avoided by redistributing conditional type I error rates of discarded markers. Our approach can be combined with cost optimal designs and entails a greater flexibility than all previously suggested designs. Among other features, it allows for marker selections based upon biological criteria instead of statistical criteria alone, or the option to modify the sample size at any time during the course of the project. For practical applicability, we develop a new algorithm, subsequently evaluate it by simulations, and illustrate it using a real data set. [source]