184 research outputs found
Functional morphology and integration of corvid skulls – a 3D geometric morphometric approach
<p>Abstract</p> <p>Background</p> <p>Sympatric corvid species have evolved differences in nesting, habitat choice, diet and foraging. Differences in the frequency with which corvid species use their repertoire of feeding techniques is expected to covary with bill-shape and with the frontal binocular field. Species that frequently probe are expected to have a relatively longer bill and more sidewise oriented orbits in contrast to species that frequently peck. We tested this prediction by analyzing computed tomography scans of skulls of six corvid species by means of three-dimensional geometric morphometrics. We (1) explored patterns of major variation using principal component analysis, (2) compared within and between species relationships of size and shape and (3) quantitatively compared patterns of morphological integration between bill and cranium by means of partial least squares (singular warp) analysis.</p> <p>Results</p> <p>Major shape variation occurs at the bill, in the orientation of orbits, in the position of the foramen magnum and in the angle between bill and cranium. The first principal component correlated positively with centroid-size, but within-species allometric relationships differed markedly. Major covariation between the bill and cranium lies in the difference in orbit orientation relative to bill-length and in the angle between bill and cranium.</p> <p>Conclusion</p> <p>Corvid species show pronounced differences in skull shape, which covary with foraging mode. Increasing bill-length, bill-curvature and sidewise orientation of the eyes is associated with an increase in the observed frequency in probing (vice versa in pecking). Hence, the frequency of probing, bill-length, bill-curvature and sidewise orientation of the eyes is progressively increased from jackdaw, to Eurasian jay, to black-billed magpie, to hooded crow, to rook and to common raven (when feeding on carcasses is considered as probing). Our results on the morphological integration suggest that most of the covariation between bill and cranium is due to differences in the topography of the binocular fields and the projection of the bill-tip therein, indicating the importance of visual fields to the foraging ecology of corvids.</p
A giant mite in Cretaceous Burmese amber
An unusually large acariform mite is described as Immensmaris
chewbaccei gen. et sp. nov. from the Cretaceous (ca. 100 Ma)
Burmese amber of Myanmar. With an idiosoma plus gnathosoma more than a
centimetre long, it represents the largest unequivocal fossil mite ever
recorded and approaches the maximum size of the largest living Acariformes
today. Although some details of the dorsal idiosoma are equivocal, the new
fossil appears to belong to Smarididae (Prostigmata: Parasitengona:
Erythraeoidea) and also represents the largest erythraeoid mite ever
discovered, indicating a clade of giant, possibly arboreal, mites in the Late
Cretaceous of southeastern Asia.</p
Algorithms and Models for Turbulence Not at Statistical Equilibrium
Standard eddy viscosity models, while robust, cannot represent backscatter
and have severe difficulties with complex turbulence not at statistical
equilibrium. This report gives a new derivation of eddy viscosity models from
an equation for the evolution of variance in a turbulent flow. The new
derivation also shows how to correct eddy viscosity models. The report proves
the corrected models preserve important features of the true Reynolds stresses.
It gives algorithms for their discretization including a minimally invasive
modular step to adapt an eddy viscosity code to the extended models. A
numerical test is given with the usual and over diffusive Smagorinsky model.
The correction (scaled by ) does successfully exhibit intermittent
backscatter.Comment: 18 pages, 2 figure
On the ornithological collection of Friedrich Sellow in Brazil (1814-1831), with some considerations about the provenance of his specimens
Abstract The Prussian naturalist Friedrich Sellow (1789-1831) traveled through Brazil, Uruguay and Argentina between 1814 and 1831 gathering numerous zoological and botanical specimens. Despite the effort spent in those countries, the ornithological collection assembled by Sellow did not receive adequate care after it had been deposited in the Zoologische Museum in Berlin, thus compromising its integrity. In the present article we discuss the treatment given by Lichtenstein and by Sellow to this bird material, with special focus on some cases in which incorrect label information on Sellow's specimens led to faulty conclusions on the zoogeography of South American birds. Key words: M. H. K. Lichtenstein, Calyptura cristata, Pipra tyranulus, Picumnus exilis, Cercomacra brasiliana Resumen El naturalista prusiano Friedrich Sellow (1789-1831) viajó a través de Brasil, Uruguay y Argentina entre 1814 y 1831 colectando numerosos materiales zoológicos y botánicos. A pesar del largo esfuerzo de muestreo hecho por él en estos paises, la colección ornitológica montada por Sellow no recibió el cuidado adecuado después de haber sido depositadas en el Zoologische Museum en Berlín, comprometiendo así su integridad. En el presente artículo discutimos el tratamiento dado por Lichtenstein y por Sellow a su material ornitológico, con especial atención en algunos casos en los cuales información equivocada en las etiquetas de sus especímenes lleva a conclusiones erradas sobre la zoogeografía de las aves Sudamericanas
DRAR-CPI: a server for identifying drug repositioning potential and adverse drug reactions via the chemical–protein interactome
Identifying new indications for existing drugs (drug repositioning) is an efficient way of maximizing their potential. Adverse drug reaction (ADR) is one of the leading causes of death among hospitalized patients. As both new indications and ADRs are caused by unexpected chemical–protein interactions on off-targets, it is reasonable to predict these interactions by mining the chemical–protein interactome (CPI). Making such predictions has recently been facilitated by a web server named DRAR-CPI. This server has a representative collection of drug molecules and targetable human proteins built up from our work in drug repositioning and ADR. When a user submits a molecule, the server will give the positive or negative association scores between the user’s molecule and our library drugs based on their interaction profiles towards the targets. Users can thus predict the indications or ADRs of their molecule based on the association scores towards our library drugs. We have matched our predictions of drug–drug associations with those predicted via gene-expression profiles, achieving a matching rate as high as 74%. We have also successfully predicted the connections between anti-psychotics and anti-infectives, indicating the underlying relevance of anti-psychotics in the potential treatment of infections, vice versa. This server is freely available at http://cpi.bio-x.cn/drar/
The role of natural science collections in the biomonitoring of environmental contaminants in apex predators in support of the EU's zero pollution ambition
The chemical industry is the leading sector in the EU in terms of added value. However, contaminants pose a major threat and significant costs to the environment and human health. While EU legislation and international conventions aim to reduce this threat, regulators struggle to assess and manage chemical risks, given the vast number of substances involved and the lack of data on exposure and hazards. The European Green Deal sets a 'zero pollution ambition for a toxic free environment' by 2050 and the EU Chemicals Strategy calls for increased monitoring of chemicals in the environment. Monitoring of contaminants in biota can, inter alia: provide regulators with early warning of bioaccumulation problems with chemicals of emerging concern; trigger risk assessment of persistent, bioaccumulative and toxic substances; enable risk assessment of chemical mixtures in biota; enable risk assessment of mixtures; and enable assessment of the effectiveness of risk management measures and of chemicals regulations overall. A number of these purposes are to be addressed under the recently launched European Partnership for Risk Assessment of Chemicals (PARC). Apex predators are of particular value to biomonitoring. Securing sufficient data at European scale implies large-scale, long-term monitoring and a steady supply of large numbers of fresh apex predator tissue samples from across Europe. Natural science collections are very well-placed to supply these. Pan-European monitoring requires effective coordination among field organisations, collections and analytical laboratories for the flow of required specimens, processing and storage of specimens and tissue samples, contaminant analyses delivering pan-European data sets, and provision of specimen and population contextual data. Collections are well-placed to coordinate this. The COST Action European Raptor Biomonitoring Facility provides a well-developed model showing how this can work, integrating a European Raptor Biomonitoring Scheme, Specimen Bank and Sampling Programme. Simultaneously, the EU-funded LIFE APEX has demonstrated a range of regulatory applications using cutting-edge analytical techniques. PARC plans to make best use of such sampling and biomonitoring programmes. Collections are poised to play a critical role in supporting PARC objectives and thereby contribute to delivery of the EU's zero-pollution ambition.Non peer reviewe
Nuclear and mitochondrial genetic structure in the Eurasian beaver (Castor fiber) - implications for future reintroductions
Many reintroduction projects for conservation fail, and there are a large number of factors that may contribute to failure. Genetic analysis can be used to help stack the odds of a reintroduction in favour of success, by conducting assessment of source populations to evaluate the possibility of inbreeding and outbreeding depression and by conducting postrelease monitoring. In this study, we use a panel of 306 SNP (single nucleotide polymorphism) markers and 487-489 base pairs of mitochondrial DNA control region sequence data to examine 321 individuals from possible source populations of the Eurasian beaver for a reintroduction to Scotland. We use this information to reassess the phylogenetic history of the Eurasian beavers, to examine the genetic legacy of past reintroductions on the Eurasian landmass and to assess the future power of the genetic markers to conduct ongoing monitoring via parentage analysis and individual identification. We demonstrate the capacity of medium density genetic data (hundreds of SNPs) to provide information suitable for applied conservation and discuss the difficulty of balancing the need for high genetic diversity against phylogenetic best fit when choosing source population(s) for reintroduction. © 2014 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd
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