2,994 research outputs found
Do glucocorticoids predict fitness? Linking environmental conditions, corticosterone and reproductive success in the blue tit, Cyanistes caeruleus
Glucocorticoids, including corticosterone (CORT), have been suggested to provide a physiological link between ecological conditions and fitness. Specifically, CORT, which is elevated in response to harsh conditions, is predicted to be correlated with reduced fitness. Yet, empirical studies show that CORT can be non-significantly, positively and negatively linked with fitness. Divergent environmental conditions between years or study systems may influence whether CORT is linked to fitness. To test this, we monitored free-living blue tits (
Cyanistes caeruleus
) during breeding over 3 years. We quantified foraging conditions during brood rearing, and examined whether they were correlated with parental baseline CORT and reproductive success. We then tested whether CORT predicted fitness. Elevated parental CORT was associated with lower temperatures, greater rainfall and lower territory-scale oak density. Whereas asynchrony with the caterpillar food peak was correlated with reduced nestling mass and fledging success, but not parental CORT. Only low temperatures were associated with both reduced nestling mass and elevated parental CORT. Despite this, parents with elevated CORT had lighter offspring in all years. Contrarily, in 2009 parental CORT was positively correlated with the number fledged. The absence of a direct link between the foraging conditions that reduce nestling quality and elevate parental CORT suggests that parental CORT may provide a holistic measure of conditions where parents are working harder to meet the demands of developing young. As the positive correlation between parental CORT and fledging success differed between years, this suggests that contrasting conditions between years can influence correlations between parental CORT and fitness. Ultimately, as CORT concentrations are intrinsically variable and linked to the prevalent conditions, studies that incorporate environmental harshness will improve our understanding of evolutionary endocrinology.
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ProGMap: an integrated annotation resource for protein orthology
Current protein sequence databases employ different classification schemes that often provide conflicting annotations, especially for poorly characterized proteins. ProGMap (Protein Group Mappings, http://www.bioinformatics.nl/progmap) is a web-tool designed to help researchers and database annotators to assess the coherence of protein groups defined in various databases and thereby facilitate the annotation of newly sequenced proteins. ProGMap is based on a non-redundant dataset of over 6.6 million protein sequences which is mapped to 240 000 protein group descriptions collected from UniProt, RefSeq, Ensembl, COG, KOG, OrthoMCL-DB, HomoloGene, TRIBES and PIRSF. ProGMap combines the underlying classification schemes via a network of links constructed by a fast and fully automated mapping approach originally developed for document classification. The web interface enables queries to be made using sequence identifiers, gene symbols, protein functions or amino acid and nucleotide sequences. For the latter query type BLAST similarity search and QuickMatch identity search services have been incorporated, for finding sequences similar (or identical) to a query sequence. ProGMap is meant to help users of high throughput methodologies who deal with partially annotated genomic data
The need for One Health systems-thinking approaches to understand multiscale dissemination of antimicrobial resistance
Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems.
The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict 'unexpected' risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems
Quantum Interference Controlled Molecular Electronics
Quantum interference in coherent transport through single molecular rings may
provide a mechanism to control current in molecular electronics. We investigate
its applicability by using a single-particle Green function method combined
with ab initio electronic structure calculations. We find that the quantum
interference effect (QIE) depends strongly on the interaction between molecular
pi states and contact sigma states. It is absent in small molecular rings with
Au leads, such as benzene, due to strong pi-sigma hybridization, while it is
preserved in large rings, such as [18]annulene, which then could be used to
realize QIE transistors.Comment: 5 pages, published version, small revision
A Large Scale Double Beta and Dark Matter Experiment: GENIUS
The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated
the large potential of double beta decay to search for new physics beyond the
Standard Model. To increase by a major step the present sensitivity for double
beta decay and dark matter search much bigger source strengths and much lower
backgrounds are needed than used in experiments under operation at present or
under construction. We present here a study of a project proposed recently,
which would operate one ton of 'naked' enriched GErmanium-detectors in liquid
NItrogen as shielding in an Underground Setup (GENIUS). It improves the
sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe
neutrino masses even down to 10^-3 eV. The first version would allow to test
the atmospheric neutrino problem, the second at least part of the solar
neutrino problem. Both versions would allow in addition significant
contributions to testing several classes of GUT models. These are especially
tests of R-parity breaking supersymmetry models, leptoquark masses and
mechanism and right-handed W-boson masses comparable to LHC. The second issue
of the experiment is the search for dark matter in the universe. The entire
MSSM parameter space for prediction of neutralinos as dark matter particles
could be covered already in a first step of the full experiment - with the same
purity requirements but using only 100 kg of 76Ge or even of natural Ge -
making the experiment competitive to LHC in the search for supersymmetry.
The layout of the proposed experiment is discussed and the shielding and
purity requirements are studied using GEANT Monte Carlo simulations. As a
demonstration of the feasibility of the experiment first results of operating a
'naked' Ge detector in liquid nitrogen are presented.Comment: 22 pages, 12 figures, see also
http://pluto.mpi-hd.mpg.de/~betalit/genius.htm
Pacific origin of the abrupt increase in Indian Ocean heat content during the warming hiatus
Global mean surface warming has stalled since the end of the twentieth century1, 2, but the net radiation imbalance at the top of the atmosphere continues to suggest an increasingly warming planet. This apparent contradiction has been reconciled by an anomalous heat flux into the ocean3, 4, 5, 6, 7, 8, induced by a shift towards a La Niña-like state with cold sea surface temperatures in the eastern tropical Pacific over the past decade or so. A significant portion of the heat missing from the atmosphere is therefore expected to be stored in the Pacific Ocean. However, in situ hydrographic records indicate that Pacific Ocean heat content has been decreasing9. Here, we analyse observations along with simulations from a global ocean–sea ice model to track the pathway of heat. We find that the enhanced heat uptake by the Pacific Ocean has been compensated by an increased heat transport from the Pacific Ocean to the Indian Ocean, carried by the Indonesian throughflow. As a result, Indian Ocean heat content has increased abruptly, which accounts for more than 70% of the global ocean heat gain in the upper 700 m during the past decade. We conclude that the Indian Ocean has become increasingly important in modulating global climate variability
CFD Investigation on Fluid Flow Analysis in Fluid Separator
The analysis of fully developed flow in the two fluid separators is an important issue in the industry such as production, processing, and petrochemical. The role of the two fluid separator is to separate two different fluid by using an appropriate mechanism without changing the quality. In this study, we have reviewed different mechanisms of two fluid separations such as gravity sedimentation, centrifugation, and electro kinetics, etc. The current work focuses on the design aspect of a fluid separator with respect to geometry and thermal design. CFD has been used to simulate flow in a fluid separator and its results have been verified experimentally. Flow rates used in the simulation have different values in interval 0.1 LPM. The study shows the best performance of fluid separator with respect to shape and flow rates. The given work helps to co-relate various design of separator in the industry with laboratory separators
Limits on the Majorana neutrino mass in the 0.1 eV range
The Heidelberg-Moscow experiment gives the most stringent limit on the
Majorana neutrino mass. After 24 kg yr of data with pulse shape measurements,
we set a lower limit on the half-life of the neutrinoless double beta decay in
76Ge of T_1/2 > 5.7 * 10^{25} yr at 90% C.L., thus excluding an effective
Majorana neutrino mass greater than 0.2 eV. This allows to set strong
constraints on degenerate neutrino mass models.Comment: 6 pages (latex) including 3 postscript figures and 2 table
De novo Biosynthesis of Biodiesel by Escherichia coli in Optimized Fed-Batch Cultivation
Biodiesel is a renewable alternative to petroleum diesel fuel that can contribute to carbon dioxide emission reduction and energy supply. Biodiesel is composed of fatty acid alkyl esters, including fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs), and is currently produced through the transesterification reaction of methanol (or ethanol) and triacylglycerols (TAGs). TAGs are mainly obtained from oilseed plants and microalgae. A sustainable supply of TAGs is a major bottleneck for current biodiesel production. Here we report the de novo biosynthesis of FAEEs from glucose, which can be derived from lignocellulosic biomass, in genetically engineered Escherichia coli by introduction of the ethanol-producing pathway from Zymomonas mobilis, genetic manipulation to increase the pool of fatty acyl-CoA, and heterologous expression of acyl-coenzyme A: diacylglycerol acyltransferase from Acinetobacter baylyi. An optimized fed-batch microbial fermentation of the modified E. coli strain yielded a titer of 922 mg L−1 FAEEs that consisted primarily of ethyl palmitate, -oleate, -myristate and -palmitoleate
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