1,638 research outputs found
Diversification rates and phenotypic evolution in venomous snakes (Elapidae)
Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.The relationship between rates of diversification and of body size change (a common proxy for phenotypic evolution) was investigated across Elapidae, the largest radiation of highly venomous snakes. Time-calibrated phylogenetic trees for 175 species of elapids (more than 50% of known taxa) were constructed using seven mitochondrial and nuclear genes. Analyses using these trees revealed no evidence for a link between speciation rates and changes in body size. Two clades (Hydrophis, Micrurus) show anomalously high rates of diversification within Elapidae, yet exhibit rates of body size evolution almost identical to the general elapid ‘background’ rate. Although correlations between speciation rates and rates of body size change exist in certain groups (e.g. ray-finned fishes, passerine birds), the two processes appear to be uncoupled in elapid snakes. There is also no detectable shift in diversification dynamics associated with the colonization of Australasia, which is surprising given that elapids appear to be the first clade of venomous snakes to reach the continent
On a pluri Gaussian model for three phase microstructures, with applications to 3D image data of gas diffusion electrodes
A pluri Gaussian model for three phase microstructures is presented and relationships between model parameters and microstructure characteristics are discussed. In particular, analytical formulas for two point coverage probability functions in terms of covariance functions of the underlying Gaussian random fields are considered, which allow for an efficient estimation of model parameters. The model is fitted to tomographic image data obtained by FIB tomography, which represent porous gas diffusion electrodes consisting of silver and polytetrafluorethylene. The considered type of electrode is used as oxygen depolarized cathode for the production of chlorine. In order to fit the microstructure model, the covariance functions of the Gaussian random fields are parameterized, which leads to a stochastic microstructure model with five parameters. It is shown that most microstructure characteristics of tomographic image data are well reproduced by the model despite the low number of model parameters. Finally, limitations of the model with respect to the fit of continuous phase size distributions are discussed. Combining stochastic microstructure modeling with numerical simulation of effective macroscopic properties will allow in future work for a model based investigation of microstructure property relationships for the considered gas diffusion electrode
"Author! Author!" : Shakespeare and biography
Original article can be found at: http://www.informaworld.com/smpp/title~content=t714579626~db=all Copyright Informa / Taylor & Francis Group. DOI: 10.1080/17450910902764454Since 1996, not a year has passed without the publication of at least one Shakespeare biography. Yet for many years the place of the author in the practice of understanding literary works has been problematized, and even on occasions eliminated. Criticism reads the “works”, and may or may not refer to an author whose “life” contributed to their meaning. Biography seeks the author in the works, the personality that precedes the works and gives them their characteristic shape and meaning. But the form of literary biography addresses the unusual kind of “life” that puts itself into “works”, and this is particularly challenging where the “works” predominate massively over the salient facts of the “life”. This essay surveys the current terrain of Shakespeare biography, and considers the key questions raised by the medium: can we know anything of Shakespeare's “personality” from the facts of his life and the survival of his works? What is the status of the kind of speculation that inevitably plays a part in biographical reconstruction? Are biographers in the end telling us as much about themselves as they tell us about Shakespeare?Peer reviewe
Deep ASKAP EMU Survey of the GAMA23 field: Properties of radio sources
We present the Australian Square Kilometre Array Pathfinder (ASKAP)
observations of the Galaxy and Mass Assembly (GAMA)-23h field. The survey was
carried out at 887.5 MHz and covers a 83 square degree field. We imaged the
calibrated visibility data, taken as part of the Evolutionary Mapping of
Universe (EMU) Early Science Programme, using the latest version of the
ASKAPSoft pipeline. The final mosaic has an angular resolution of 10 arcsec and
a central rms noise of around 38 Jy beam. The derived radio source
catalogue has 39812 entries above a peak flux density threshold of 5.
We searched for the radio source host galaxy counterparts using the GAMA
spectroscopic (with an i-band magnitude limit of 19.2 mag) and multi-wavelength
catalogues that are available as part of the collaboration. We identified hosts
with GAMA spectroscopic redshifts for 5934 radio sources. We describe the data
reduction, imaging, and source identification process, and present the source
counts. Thanks to the wide area covered by our survey, we obtain very robust
counts down to 0.2 mJy. ASKAP's exceptional survey speed, providing efficient,
sensitive and high resolution mapping of large regions of the sky in
conjunction with the multi-wavelength data available for the GAMA23 field,
allowed us to discover 63 giant radio galaxies. The data presented here
demonstrate the excellent capabilities of ASKAP in the pre-SKA era.Comment: 18 pages, 15 figures, accepted by MNRA
Triangleland. I. Classical dynamics with exchange of relative angular momentum
In Euclidean relational particle mechanics, only relative times, relative
angles and relative separations are meaningful. Barbour--Bertotti (1982) theory
is of this form and can be viewed as a recovery of (a portion of) Newtonian
mechanics from relational premises. This is of interest in the absolute versus
relative motion debate and also shares a number of features with the
geometrodynamical formulation of general relativity, making it suitable for
some modelling of the problem of time in quantum gravity. I also study
similarity relational particle mechanics (`dynamics of pure shape'), in which
only relative times, relative angles and {\sl ratios of} relative separations
are meaningful. This I consider firstly as it is simpler, particularly in 1 and
2 d, for which the configuration space geometry turns out to be well-known,
e.g. S^2 for the `triangleland' (3-particle) case that I consider in detail.
Secondly, the similarity model occurs as a sub-model within the Euclidean
model: that admits a shape--scale split. For harmonic oscillator like
potentials, similarity triangleland model turns out to have the same
mathematics as a family of rigid rotor problems, while the Euclidean case turns
out to have parallels with the Kepler--Coulomb problem in spherical and
parabolic coordinates. Previous work on relational mechanics covered cases
where the constituent subsystems do not exchange relative angular momentum,
which is a simplifying (but in some ways undesirable) feature paralleling
centrality in ordinary mechanics. In this paper I lift this restriction. In
each case I reduce the relational problem to a standard one, thus obtain
various exact, asymptotic and numerical solutions, and then recast these into
the original mechanical variables for physical interpretation.Comment: Journal Reference added, minor updates to References and Figure
Cross-cultural neuropsychological assessment in Europe: Position statement of the European Consortium on Cross-Cultural Neuropsychology (ECCroN)
Over the past decades European societies have become increasingly diverse. This diversity in culture, education, and language significantly impacts neuropsychological assessment. Although several initiatives are under way to overcome these barriers - e.g. newly developed and validated test batteries - there is a need for more collaboration in the development and implementation of neuropsychological tests, such as in the domains of social cognition and language. To address these gaps in cross-cultural neuropsychological assessment in Europe, the European Consortium on Cross-Cultural Neuropsychology (ECCroN) was established in 2019. ECCroN recommends taking a broad range of variables into account, such as linguistic factors, literacy, education, migration history, acculturation and other cultural factors. We advocate against race-based norms as a solution to the challenging interpretation of group differences on neuropsychological tests, and instead support the development, validation, and standardization of more widely applicable/cross-culturally applicable tests that take into account interindividual variability. Last, ECCroN advocates for an improvement in the clinical training of neuropsychologists in culturally sensitive neuropsychological assessment, and the development and implementation of guidelines for interpreter-mediated neuropsychological assessment in diverse populations in Europe. ECCroN may impact research and clinical practice by contributing to existing theoretical frameworks and by improving the assessment of diverse individuals across Europe through collaborations on test development, collection of normative data, cross-cultural clinical training, and interpreter-mediated assessment
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