2,018 research outputs found
Embracing polygenicity: a review of methods and tools for psychiatric genetics research.
The availability of genome-wide genetic data on hundreds of thousands of people has led to an equally rapid growth in methodologies available to analyse these data. While the motivation for undertaking genome-wide association studies (GWAS) is identification of genetic markers associated with complex traits, once generated these data can be used for many other analyses. GWAS have demonstrated that complex traits exhibit a highly polygenic genetic architecture, often with shared genetic risk factors across traits. New methods to analyse data from GWAS are increasingly being used to address a diverse set of questions about the aetiology of complex traits and diseases, including psychiatric disorders. Here, we give an overview of some of these methods and present examples of how they have contributed to our understanding of psychiatric disorders. We consider: (i) estimation of the extent of genetic influence on traits, (ii) uncovering of shared genetic control between traits, (iii) predictions of genetic risk for individuals, (iv) uncovering of causal relationships between traits, (v) identifying causal single-nucleotide polymorphisms and genes or (vi) the detection of genetic heterogeneity. This classification helps organise the large number of recently developed methods, although some could be placed in more than one category. While some methods require GWAS data on individual people, others simply use GWAS summary statistics data, allowing novel well-powered analyses to be conducted at a low computational burden
Is J 133658.3-295105 a Radio Source at z >= 1.0 or at the Distance of M 83?
We present Gemini optical imaging and spectroscopy of the radio source J
133658.3-295105. This source has been suggested to be the core of an FR II
radio source with two detected lobes. J 133658.3-295105 and its lobes are
aligned with the optical nucleus of M 83 and with three other radio sources at
the M 83 bulge outer region. These radio sources are neither supernova remnants
nor H II regions. This curious configuration prompted us to try to determine
the distance to J 133658.3-295105. We detected H_alpha emission redshifted by ~
130 km s^-1 with respect to an M 83 H II region 2.5" east-southeast of the
radio source. We do not detect other redshifted emission lines of an optical
counterpart down to m_i = 22.2 +/- 0.8. Two different scenarios are proposed:
the radio source is at z >= 2.5, a much larger distance than the previously
proposed lower limit z >= 1.0, or the object was ejected by a gravitational
recoil event from the M 83 nucleus. This nucleus is undergoing a strong
dynamical evolution, judging from previous three-dimensional spectroscopy.Comment: 6 pages, 4 figure
Implications of short-range spatial variation of soil bulk density for adequate field-sampling protocols: methodology and results from two contrasting soils
Soil bulk density (BD) is measured during soil monitoring. Because it is spatially variable, an appropriate sampling protocol is required. This paper shows how information on short-range variability can be used to quantify uncertainty of estimates of mean BD and soil organic carbon on a volumetric basis (SOCv) at a sampling site with different sampling intensities. We report results from two contrasting study areas, with mineral soil and with peat. More sites should be investigated to develop robust protocols for national-scale monitoring, but these results illustrate the methodology. A 20 × 20-m2 monitoring site was considered and sampling protocols were evaluated under geostatistical models of our two study areas. At sites with local soil variability comparable to our mineral soil, sampling at 16 points (4 × 4 square grid of interval 5 m) would achieve a root mean square error (RMSE) of the sample mean value of both BD and SOCv of less than 5% of the mean (topsoil and subsoil). Pedotransfer functions (PTFs) gave predictions of mean soil BD at a sample site, comparable to our study area on mineral soil, with similar precision to a single direct measurement of BD. On peat soils comparable to our second study area, the mean BD for the monitoring site at depth 0–50 cm would be estimated with RMSE to be less than 5% of the mean with a sample of 16 cores, but at greater depths this criterion cannot be achieved with 25 cores or fewer
Convex Polytopes and Quasilattices from the Symplectic Viewpoint
We construct, for each convex polytope, possibly nonrational and nonsimple, a
family of compact spaces that are stratified by quasifolds, i.e. each of these
spaces is a collection of quasifolds glued together in an suitable way. A
quasifold is a space locally modelled on modulo the action of a
discrete, possibly infinite, group. The way strata are glued to each other also
involves the action of an (infinite) discrete group. Each stratified space is
endowed with a symplectic structure and a moment mapping having the property
that its image gives the original polytope back. These spaces may be viewed as
a natural generalization of symplectic toric varieties to the nonrational
setting.Comment: LaTeX, 29 pages. Revised version: TITLE changed, reorganization of
notations and exposition, added remarks and reference
History-sensitive accumulation rules for life-time prediction under variable loading
This is the post-print version of the article. The official published version can be obtained from the link below - Copyright @ 2011 SpringerA general form of temporal strength conditions under variable creep loading is employed to formulate several new phenomenological accumulation rules based on the constant-loading durability diagram. Unlike the well-known Robinson rule of linear accumulation of partial life-times, the new rules allow to describe the life-time sensibility to the load sequence, observed in experiments. Comparison of the new rules with experimental data shows that they fit the data much more accurately than the Robinson rule
The most creative organization in the world? The BBC, 'creativity' and managerial style
The managerial styles of two BBC directors-general, John Birt and Greg Dyke, have often been contrasted but not so far analysed from the perspective of their different views of 'creative management'. This article first addresses the orthodox reading of 'Birtism'; second, it locates Dyke's 'creative' turn in the wider context of fashionable neo-management theory and UK government creative industries policy; third, it details Dyke's drive to change the BBC's culture; and finally, it concludes with some reflections on the uncertainties inherent in managing a creative organisation
Calculation of AGARD Wing 445.6 Flutter Using Navier-Stokes Aerodynamics
An unsteady, 3D, implicit upwind Euler/Navier-Stokes algorithm is here used to compute the flutter characteristics of Wing 445.6, the AGARD standard aeroelastic configuration for dynamic response, with a view to the discrepancy between Euler characteristics and experimental data. Attention is given to effects of fluid viscosity, structural damping, and number of structural model nodes. The flutter characteristics of the wing are determined using these unsteady generalized aerodynamic forces in a traditional V-g analysis. The V-g analysis indicates that fluid viscosity has a significant effect on the supersonic flutter boundary for this wing
Extremal limit of the regular charged black holes in nonlinear electrodynamics
The near horizon limit of the extreme nonlinear black hole is investigated.
It is shown that resulting geometry belongs to the AdS2xS2 class with different
modules of curvatures of subspaces and could be described in terms of the
Lambert functions. It is demonstrated that the considered class of Lagrangians
does not admit solutions of the Bertotti-Robinson type
On the energy of charged black holes in generalized dilaton-axion gravity
In this paper we calculate the energy distribution of some charged black
holes in generalized dilaton-axion gravity. The solutions correspond to charged
black holes arising in a Kalb-Ramond-dilaton background and some existing
non-rotating black hole solutions are recovered in special cases. We focus our
study to asymptotically flat and asymptotically non-flat types of solutions and
resort for this purpose to the M{\o}ller prescription. Various aspects of
energy are also analyzed.Comment: LaTe
Cold Plasma Dispersion Relations in the Vicinity of a Schwarzschild Black Hole Horizon
We apply the ADM 3+1 formalism to derive the general relativistic
magnetohydrodynamic equations for cold plasma in spatially flat Schwarzschild
metric. Respective perturbed equations are linearized for non-magnetized and
magnetized plasmas both in non-rotating and rotating backgrounds. These are
then Fourier analyzed and the corresponding dispersion relations are obtained.
These relations are discussed for the existence of waves with positive angular
frequency in the region near the horizon. Our results support the fact that no
information can be extracted from the Schwarzschild black hole. It is concluded
that negative phase velocity propagates in the rotating background whether the
black hole is rotating or non-rotating.Comment: 27 pages, 11 figures accepted for publication in Gen. Relat. & Gravi
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