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Results 201 - 250 of 3639
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Bager Alex - - 2011
Road-killed mammals, birds, and reptiles were collected weekly from highways in southern Brazil in 2002 and 2005. The objective was to assess variation in estimates of road-kill impacts on species richness produced by different sampling efforts, and to provide information to aid in the experimental design of future sampling. Richness ...
Jarnevich Catherine S - - 2011
Alternative energy development is increasing, potentially leading to negative impacts on wildlife populations already stressed by other factors. Resource managers require a scientifically based methodology to balance energy development and species conservation, so we investigated modeling habitat suitability using Maximum Entropy to develop maps that could be used with other ...
Kamermans Maarten - - 2011
In this review, we will discuss the recent literature on fish polarization vision and we will present a model on how the retina processes polarization signals. The model is based on a general retinal-processing scheme and will be compared with the available electrophysiological data on polarization processing in the retina. ...
Davydov Dmitri R DR University of California - San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA 92093, USA. - - 2011
There is increasing evidence of physical interactions (association) among cytochromes P450 in the membranes of the endoplasmic reticulum. Functional consequences of these interactions are often underestimated. This article provides a comprehensive overview of available experimental material regarding P450-P450 interactions. Special emphasis is given to the interactions between different P450 species ...
Zu Jian - - 2011
On the ecological timescale, two predator species with linear functional responses can stably coexist on two competing prey species. In this paper, with the methods of adaptive dynamics and critical function analysis, we investigate under what conditions such a coexistence is also evolutionarily stable, and whether the two predator species ...
Kubatko Laura S - - 2011
Phylogenetic relationships and taxonomic distinctiveness of closely related species and subspecies are most accurately inferred from data derived from multiple independent loci. Here, we apply several approaches for understanding species-level relationships using data from 18 nuclear DNA loci and 1 mitochondrial DNA locus within currently described species and subspecies of ...
Du Xiaoguang - - 2011
The debate on the role of species differences in shaping biodiversity patterns, with its two extremes of pure niche theory and neutral theory, is still ongoing. It has been demonstrated that a slight difference in competitive ability of species severely affects the predictions of the neutral model. At the same ...
Price S A - - 2011
Although coral reefs are renowned biodiversity hotspots it is not known whether they also promote the evolution of exceptional ecomorphological diversity. We investigated this question by analysing a large functional morphological dataset of trophic characters within Labridae, a highly diverse group of fishes. Using an analysis that accounts for species ...
van Beest Floris M - - 2011
1. Most studies of intraspecific variation in home range size have investigated only a single or a few factors and often at one specific scale. However, considering multiple spatial and temporal scales when defining a home range is important as mechanisms that affect variation in home range size may differ depending ...
Shephard Samuel - - 2011
Biomass and production in the marine benthic community typically show rapid declines with bottom trawling. It has been postulated that such incidental reductions in prey abundance with trawling might negatively influence feeding success and hence the body condition of benthivorous fish. Length/weight and density by haul per year for six ...
Chapple Taylor K - - 2011
The decline of sharks in the global oceans underscores the need for careful assessment and monitoring of remaining populations. The northeastern Pacific is the home range for a genetically distinct clade of white sharks (Carcharodon carcharias). Little is known about the conservation status of this demographically isolated population, concentrated seasonally ...
Karlsson Fredrik H - - 2011
Abundant microorganisms that inhabit the human intestine are implicated in health and disease. The gut microbiome has been studied with metagenomic tools, and over 3 million genes have been discovered, constituting a 'parts list' of this ecosystem; further understanding requires studies of the interacting parts. Mouse models have provided a ...
Aldous David J - - 2011
Stochastic modeling of phylogenies raises five questions that have received varying levels of attention from quantitatively inclined biologists. 1) How large do we expect (from the model) the ratio of maximum historical diversity to current diversity to be? 2) From a correct phylogeny of the extant species of a clade, ...
Wallmo Kristy - - 2011
Non-market valuation research has produced value estimates for over forty threatened and endangered (T&E) species, including mammals, fish, birds, and crustaceans. Increasingly, Stated Preference Choice Experiments (SPCE) are utilized for valuation, as the format offers flexibility for policy analysis and may reduce certain types of response biases relative to the ...
Poe Steven - - 2011
The distributions and characteristics of naturalized species may be explained by novel anthropogenous aspects of world biogeography such as the creation of favorable transport environments for propagules on ships. Conversely, the unprecedented connectivity of humans may simply accelerate omnipresent ecological and evolutionary forces, for example, ships may allow species that ...
Girod Christophe - - 2011
Reconstructing the demographic history of populations is a central issue in evolutionary biology. Using likelihood-based methods coupled with Monte Carlo simulations, it is now possible to reconstruct past changes in population size from genetic data. Using simulated data sets under various demographic scenarios, we evaluate the statistical performance of Msvar, ...
Lim Dong-Hee - - 2011
Polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) may pose a worldwide pollution problem because of their persistence, long-range transport capability, and predisposition to bioaccumulate. The ubiquitous presence of PBBs and PBDEs has heightened interest in determination of their fate. We report results for a fugacity-based dynamic environmental and bioaccumulation ...
van Wilgenburg E - - 2011
The cuticular hydrocarbons (CHCs) of ants provide important cues for nest-mate and caste recognition. There is enormous diversity in the composition of these CHCs, but the manner in which this diversity has evolved is poorly understood. We gathered data on CHC profiles for 56 ant species, relating this information to ...
Bowles Samuel S Santa Fe Institute, Santa Fe, NM 87501, USA. - - 2011
Did foragers become farmers because cultivation of crops was simply a better way to make a living? If so, what is arguably the greatest ever revolution in human livelihoods is readily explained. To answer the question, I estimate the caloric returns per hour of labor devoted to foraging wild species ...
Jansen Mieke - - 2011
Natural populations that are exposed to pesticides in their environment may at the same time be exposed to natural stressors like parasites and predators, which may interact with pesticide exposure. This may not only impact target pest species but also a wide variety of non-target species. This review reports on ...
Rollinson Njal - - 2011
Positive associations between maternal investment per offspring and maternal body size have been explained as adaptive responses by females to predictable, body size-specific maternal influences on the offspring's environment. As a larger per-offspring investment increases maternal fitness when the quality of the offspring environment is low, optimal egg size may ...
Reynolds Craig - - 2011
Abstract This article presents an abstract computation model of the evolution of camouflage in nature. The 2D model uses evolved textures for prey, a background texture representing the environment, and a visual predator. A human observer, acting as the predator, is shown a cohort of ten evolved textures overlaid on ...
Bogdanowicz Damian - - 2011
The reconstruction of evolutionary trees is one of the primary objectives in phylogenetics. Such a tree represents the historical evolutionary relationship between different species or organisms. Tree comparisons are used for multiple purposes, from unveiling the history of species to deciphering evolutionary associations among organisms and geographical areas. In the ...
Mehner Thomas - - 2011
1. Field studies on diel vertical migration (DVM) usually report uniform behaviour with population-wide ascents and descents during crepuscular periods. This contrasts partial seasonal migrations of many animal populations, where individuals choose either the resident or the migrant strategy depending on population density, feeding opportunity and predation risk in the resident ...
Hamilton Trinity L - - 2011
Biological nitrogen fixation is a keystone process in many ecosystems, providing bioavailable forms of fixed nitrogen for members of the community. In the present study, degenerate primers targeting the nitrogenase iron protein-encoding gene (nifH) were designed and employed to investigate the physical and chemical parameters that underpin the distribution and ...
Iserbyt Arne - - 2011
Contemporary theory predicts that the degree of mimetic similarity of mimics towards their model should increase as the mimic/model ratio increases. Thus, when the mimic/model ratio is high, then the mimic has to resemble the model very closely to still gain protection from the signal receiver. To date, empirical evidence ...
Holzman Roi - - 2011
Abstract Trade-offs are believed to impose major constraints on adaptive evolution, and they arise when modification of a trait improves one aspect of performance but incurs a cost in another. Here we show that performance costs that result from competing demands on one trait can be mitigated by compensatory changes ...
Gabriel y Galán José María - - 2011
Morphological stomatal traits, such as size, form and frequency, have been subject of much literature, including their relationships with environmental factors. However, little effort have focused on ferns, and very few in the genus Blechnum. Stomatal length, width and frequency (as stomatal index) of a number of specimens of fourteen ...
Novaes José Luís Costa - - 2011
Hoplias malabaricus is a viable economic alternative for artisanal fishermen who used to live on the banks of rivers that now are dammed in Brazil. In order to preserve the species' natural stock, the main objectives of this study were to obtain bio-ecological information on this species reproduction, feeding dynamics ...
Bueno-Marí Rubén - - 2011
We present a classification of Spanish mosquitoes according to their different life cycles. The bio-ecological parameters analyzed in our study were oviposition sites, overwintering stages, preferred hosts, and number of generations per year for each species. The results revealed 13 different functional groups. To assess the validity and robustness of ...
Farias Ariel A - - 2011
1. Changes in land use and habitat fragmentation are major drivers of global change, and studying their effects on biodiversity constitutes a major research programme. However, biodiversity is a multifaceted concept, with a functional component linking species richness to ecosystem function. Currently, the interaction between functional and taxonomic components of biodiversity ...
Mailund Thomas T Bioinformatics Research Centre, Aarhus University, Denmark. - - 2011
Due to genetic variation in the ancestor of two populations or two species, the divergence time for DNA sequences from two populations is variable along the genome. Within genomic segments all bases will share the same divergence-because they share a most recent common ancestor-when no recombination event has occurred to ...
Gómez-Corral A - - 2011
We investigate a stochastic model for the competition between two species. Based on percentiles of the maximum number of individuals in the ecosystem, we present an approximating model for which the extinction time can be thought of as a phase-type random variable. We determine formulae for the probabilities of extinction ...
Billiard Sylvain - - 2011
Disentangling the processes leading populations to extinction is a major topic in ecology and conservation biology. The difficulty to find a mate in many species is one of these processes. Here, we investigate the impact of self-incompatibility in flowering plants, where several inter-compatible classes of individuals exist but individuals of ...
Green Darren Michael - - 2011
Partitioning of contact networks into communities allows groupings of epidemiologically related nodes to be derived, that could inform the design of disease surveillance and control strategies, e.g. contact tracing or design of 'firebreaks' for disease spread. However, these are only of merit if they persist longer than the timescale of ...
Burgess Malcolm D - - 2011
1. Spatial variation in habitat quality and its demographic consequences have important implications for the regulation of animal populations. Theoretically, habitat quality is typically viewed as a single gradient from 'poor' to 'good', but in wild populations it is possible that there are multiple environmental gradients that determine spatial variation in ...
Paiva Thiago da Silva Tda - - 2012
Morphology of the urostylid ciliate Hemicycliostyla sphagni Stokes, 1886, the type of Hemicycliostyla Stokes, 1886, is investigated based on live and protargol-impregnated specimens from a Brazilian population. The absence of transverse cirri, which has been considered the main diagnostic feature of Hemicycliostyla, separating it from Pseudourostyla Borror, 1972, was found ...
Hoffmann Ary A - - 2011
Evolutionary adaptation can be rapid and potentially help species counter stressful conditions or realize ecological opportunities arising from climate change. The challenges are to understand when evolution will occur and to identify potential evolutionary winners as well as losers, such as species lacking adaptive capacity living near physiological limits. Evolutionary ...
Zhang Xiaoshuan - - 2011
BACKGROUND: Tilapia has been named as the 'food fish of the 21st century' and has become the most important farmed fish. China is the world leader in tilapia production and export. Identifying information and functional requirements is critical in developing an efficient traceability system because traceability has become a fundamental ...
Hidalgo-Galiana Amparo - - 2011
We provide a reconstruction of the phylogenetic relationships, the geographical and temporal origin, and the mode of diversification of the Mediterranean species of the aquatic beetle family Hydrochidae (Coleoptera, Hydrophiloidea). A total of ca. 3 KB of sequence data of three mitochondrialand two nuclear genes were used to reconstruct the ...
Zafar Mazhar Iqbal - - 2011
The present study compared the effects of different time-variable exposure regimes having the same Time-Weighted Average (TWA) concentration of the organophosphate insecticide chlorpyrifos on freshwater invertebrate communities, to enable extrapolation of effects across exposure regimes. The experiment was performed in outdoor microcosms by introducing three different regimes: (1) a single ...
Wang I-Lin - - 2011
Although the haplotype data can be used to analyze the function of DNA, due to the significant efforts required in collecting the haplotype data, usually the genotype data is collected and then the population haplotype inference (PHI) problem is solved to infer haplotype data from genotype data for a population. ...
Grey Erin K - - 2011
The success of exotic species can be influenced by both the abiotic environment and species interactions. Many studies have demonstrated significant effects of either type of factor on aspects of exotic success, but few have considered their relative effects on population growth rate, a more holistic measure of success. To ...
Beheim Bret A - - 2011
We consider patterns in the evolution of canoe technology in the eastern Pacific relative to three general processes: movement of canoe traits along the Polynesian settlement sequence, adaptations to local island environment, and post-settlement interaction between island groups. Using model selection methods on the distributions of canoe technology, we show ...
Heier Lise - - 2011
Predicting the dynamics of zoonoses in wildlife is important not only for prevention of transmission to humans, but also for improving the general understanding of epidemiological processes. A large dataset on sylvatic plague in the Pre-Balkhash area of Kazakhstan (collected for surveillance purposes) provides a rare opportunity for detailed statistical ...
Don Emily K - - 2011
We describe the morphology of a zebrafish strain which lacks pelvic fins but no other abnormalities. This description is the first step of analyzing hindlimb loss in an established model organism. By combining light microscopy, bone and cartilage staining, scanning electron microscopy and histological sections we were able to comprehensively ...
Lance Emilie - - 2011
Our previous studies showed that microcystin (MC)-accumulation in the gastropod Lymnaea stagnalis and effects on life-history traits (survival, growth, and fecundity) varied according to age, exposure pathway (MC-producing cyanobacteria or dissolved MC), and presence or not of additional non-toxic food. This study investigated effects of exposure to MC-producing cyanobacteria or ...
Johnson Pieter T J - - 2011
  Ecological theory predicts that species with restricted geographic ranges will have the highest probability of extinction, but species with extensive distributions and high population densities can also exhibit widespread population losses. In the western United States populations of northern leopard frogs (Lithobates pipiens)-historically one of the most widespread frogs ...
Yackulic Charles B - - 2011
The extinction of a species is inevitably preceded by the extirpation of a series of local populations. Ecological theory predicts that vulnerability to extirpation varies between populations and is ultimately linked to environmental heterogeneity. If populations of a species are present in multiple regions separated by abrupt changes in environmental ...
Asher R J - - 2011
Patterns of vertebral variation across mammals have seldom been quantified, making it difficult to test hypotheses of covariation within the axial skeleton and mechanisms behind the high level of vertebral conservatism among mammals. We examined variation in vertebral counts within 42 species of mammals, representing monotremes, marsupials and major clades ...
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