3,358 research outputs found
Polymorphic characterisation of gallinacin candidate genes and their molecular associations with growth and immunity traits in chickens
1.Four gallinacin (GAL) genes were assessed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) to characterise these genes in Fayoumi (F) and Rhode Island Red (R) breeds and their crosses of Rhode Island Red × Fayoumi (½R½F) and Fayoumi × Rhode Island Red (½F½R). 2.Genes examined were GAL2, GAL3, GAL4 and GAL5. The molecular associations between the SNPs of the gallinacin genes and body weight, caecal bacterial count and the serum antibody titres of IgA, IgG and IgM were determined. In the R breed, the frequency of TC genotype was higher than TT and CC genotypes for the GAL3 gene. The GG genotype frequency was higher than AA and AG genotypes for the GAL4 gene in the other genetic groups, and the CA genotype frequency was higher than CC and AA genotypes in crosses for the GAL5 gene. 3.In all populations, the frequency of the C allele was higher than the T allele for the GAL3 gene, the G allele was higher than the A allele for the GAL4 gene and the C allele was higher than the A allele for the GAL5 gene. The observed heterozygosity in R, ½R½F and ½F½R was 0.476, 0.375 and 0.158 for the GAL3 gene, 0.458, 0.615 and 0.250 for the GAL4 gene and 0.053, 0.792 and 0.739 for the GAL5 gene, while the expected heterozygosities were 0.490, 0.430 and 0.145 for the GAL3 gene, 0.430, 0.348 and 0.219 for the GAL4 gene and 0.229, 0.478 and 0.496 for the GAL5 gene, respectively. 4.On a molecular level, the genotype TT was significantly higher for body weight than TC and CC genotypes in the GAL3 gene. Birds with the GG genotype had a significantly lower Salmonella typhimurium count than birds with AA genotype in the GAL4 gene. Birds with the genotype AA had higher significant body weights than those with CC and CA genotypes in the GAL5 gene. 5.The results indicated that the GAL3, GAL4 and GAL5 genes are potential candidates for selection programmes to improve S. typhimurium resistance and body weight in chickens
Initial data for Einstein's equations with superposed gravitational waves
A method is presented to construct initial data for Einstein's equations as a
superposition of a gravitational wave perturbation on an arbitrary stationary
background spacetime. The method combines the conformal thin sandwich formalism
with linear gravitational waves, and allows detailed control over
characteristics of the superposed gravitational wave like shape, location and
propagation direction. It is furthermore fully covariant with respect to
spatial coordinate changes and allows for very large amplitude of the
gravitational wave.Comment: Version accepted by PRD; added convergence plots, expanded
discussion. 9 pages, 9 figure
Photocurrent response of B12As2 crystals to blue light, and its temperature-dependent electrical characterizations
Citation: Gul, R., Cui, Y., Bolotnikov, A. E., Camarda, G. S., Egarievwe, S. U., Hossain, A., . . . James, R. B. (2016). Photocurrent response of B12As2 crystals to blue light, and its temperature-dependent electrical characterizations. Aip Advances, 6(2), 6. doi:10.1063/1.4941937With the global shortage of He-3 gas, researchers worldwide are looking for alternative materials for detecting neutrons. Among the candidate materials, semiconductors are attractive because of their light weight and ease in handling. Currently, we are looking into the suitability of boron arsenide (B12As2) for this specific application. As the first step in evaluating the material qualitatively, the photo-response of B12As2 bulk crystals to light with different wavelengths was examined. The crystals showed photocurrent response to a band of 407- and 470- nm blue light. The maximum measured photoresponsivity and the photocurrent density at 0.7 V for 470 nm blue light at room temperature were 0.25 A.W-1 and 2.47 mA.cm(-2), respectively. In addition to photo current measurements, the electrical properties as a function of temperature (range: 50-320 K) were measured. Reliable data were obtained for the low-temperature I-V characteristics, the temperature dependence of dark current and its density, and the resistivity variations with temperature in B12As2 bulk crystals. The experiments showed an exponential dependence on temperature for the dark current, current density, and resistivity; these three electrical parameters, respectively, had a variation of a few nA to mu A, 1-100 mu A.cm(-2) and 7.6x10(5)-7.7x10(3) Omega.cm, for temperature increasing from 50 K to 320 K. The results from this study reported the first photoresponse and demonstrated that B12As2 is a potential candidate for thermal-neutron detectors. (C) 2016 Author(s)
Finding Apparent Horizons in Dynamic 3D Numerical Spacetimes
We have developed a general method for finding apparent horizons in 3D
numerical relativity. Instead of solving for the partial differential equation
describing the location of the apparent horizons, we expand the closed 2D
surfaces in terms of symmetric trace--free tensors and solve for the expansion
coefficients using a minimization procedure. Our method is applied to a number
of different spacetimes, including numerically constructed spacetimes
containing highly distorted axisymmetric black holes in spherical coordinates,
and 3D rotating, and colliding black holes in Cartesian coordinates.Comment: 19 pages, 13 figures, LaTex, to appear in Phys. Rev. D. Minor changes
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Statistics of electromagnetic transitions as a signature of chaos in many-electron atoms
Using a configuration interaction approach we study statistics of the dipole
matrix elements (E1 amplitudes) between the 14 lower odd states with J=4 and
21st to 100th even states with J=4 in the Ce atom (1120 lines). We show that
the distribution of the matrix elements is close to Gaussian, although the
width of the Gaussian distribution, i.e. the root-mean-square matrix element,
changes with the excitation energy. The corresponding line strengths are
distributed according to the Porter-Thomas law which describes statistics of
transition strengths between chaotic states in compound nuclei. We also show
how to use a statistical theory to calculate mean squared values of the matrix
elements or transition amplitudes between chaotic many-body states. We draw
some support for our conclusions from the analysis of the 228 experimental line
strengths in Ce [J. Opt. Soc. Am. v. 8, p. 1545 (1991)], although direct
comparison with the calculations is impeded by incompleteness of the
experimental data. Nevertheless, the statistics observed evidence that highly
excited many-electron states in atoms are indeed chaotic.Comment: 16 pages, REVTEX, 4 PostScript figures (submitted to Phys Rev A
Adaptive computation of gravitational waves from black hole interactions
We construct a class of linear partial differential equations describing
general perturbations of non-rotating black holes in 3D Cartesian coordinates.
In contrast to the usual approach, a single equation treats all radiative modes simultaneously, allowing the study of wave perturbations of black
holes with arbitrary 3D structure, as would be present when studying the full
set of nonlinear Einstein equations describing a perturbed black hole. This
class of equations forms an excellent testbed to explore the computational
issues of simulating black spacetimes using a three dimensional adaptive mesh
refinement code. Using this code, we present results from the first fully
resolved 3D solution of the equations describing perturbed black holes. We
discuss both fixed and adaptive mesh refinement, refinement criteria, and the
computational savings provided by adaptive techniques in 3D for such model
problems of distorted black holes.Comment: 16 Pages, RevTeX, 13 figure
Stable characteristic evolution of generic 3-dimensional single-black-hole spacetimes
We report new results which establish that the accurate 3-dimensional
numerical simulation of generic single-black-hole spacetimes has been achieved
by characteristic evolution with unlimited long term stability. Our results
cover a selection of distorted, moving and spinning single black holes, with
evolution times up to 60,000M.Comment: 4 pages, 3 figure
Gravitational wave extraction and outer boundary conditions by perturbative matching
We present a method for extracting gravitational radiation from a
three-dimensional numerical relativity simulation and, using the extracted
data, to provide outer boundary conditions. The method treats dynamical
gravitational variables as nonspherical perturbations of Schwarzschild
geometry. We discuss a code which implements this method and present results of
tests which have been performed with a three dimensional numerical relativity
code
Boosted three-dimensional black-hole evolutions with singularity excision
Binary black hole interactions provide potentially the strongest source of
gravitational radiation for detectors currently under development. We present
some results from the Binary Black Hole Grand Challenge Alliance three-
dimensional Cauchy evolution module. These constitute essential steps towards
modeling such interactions and predicting gravitational radiation waveforms. We
report on single black hole evolutions and the first successful demonstration
of a black hole moving freely through a three-dimensional computational grid
via a Cauchy evolution: a hole moving ~6M at 0.1c during a total evolution of
duration ~60M
Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism.
Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells
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