985 research outputs found
Thermodynamic Properties of Ferromagnetic Mott- Insulators GaV4S8
We present the results of the magnetic and specific heat measurements on V4
tetrahedral-cluster compound GaV4S8 between 2 to 300K. We find two transitions
related to a structural change at 42K followed by ferromagnetic order at 12K on
cooling. Remarkably similar properties were previously reported for the cluster
compounds of Mo4. These compounds show an extremely high density of low energy
excitations in their electronic properties. We explain this behavior in a
cluster compound as due to the reduction of coulomb repulsion among electrons
that occupy highly degenerate orbits of different clusters.Comment: To be publish in Physica
Excitation energy dependence of electron-phonon interaction in ZnO nanoparticles
Raman spectroscopic investigations are carried out on ZnO nanoparticles for
various photon energies. Intensities of E1-LO and E2 modes exhibit large
changes as the excitation energy varied from 2.41 to 3.815 eV, signifying
substantially large contribution of Frohlich interaction to the Raman
polarizability as compared to deformation potential close to the resonance.
Relative strength of these two mechanisms is estimated for the first time in
nanoparticles and compared with those in the bulk.Comment: 13 pages. 3 figures Journa
POLYMORPHISMS OF GROWTH HORMONE GENE IN HARINGHATA BLACK CHICKEN
The present study was carried out with an aim to investigate the genetic variability of growth
hormone gene in Haringhata Black chicken. Blood samples were collected from 82 experimental birds and
genomic DNA was extracted using the modified high salt method. Amplification of specific DNA fragment of
intron 4 of growth hormone gene yielded a product size of 713 bp and was analyzed for polymorphism using
PCR-SSCP technique. The banding pattern of present investigation revealed two SSCP variants AA and BB
genotype in all experimental birds. In the analysed flock of Haringhata Black Chicken, the genotype frequencies
were found to be 0.915 for AA and 0.085 for BB genotype. The frequencies of A and B alleles were 0.915 and
0.085 respectively which indicated A allele was predominant in the studied Haringhata Black Chicken population
of the farm. The Chi Square Test revealed that studied population was not in accordance with Hardy Weinberg
equilibrium with respect to intron 4 of Growth hormone gene
The STAR Photon Multiplicity Detector
Details concerning the design, fabrication and performance of STAR Photon
Multiplicity Detector (PMD) are presented. The PMD will cover the forward
region, within the pseudorapidity range 2.3--3.5, behind the forward time
projection chamber. It will measure the spatial distribution of photons in
order to study collective flow, fluctuation and chiral symmetry restoration.Comment: 15 pages, including 11 figures; to appear in a special NIM volume
dedicated to the accelerator and detectors at RHI
Carbon cycle uncertainty in the Alaskan Arctic
Climate change is leading to a disproportionately
large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for the Alaskan Arctic from four recent model intercomparison projects – NACP (North American Carbon Program) site and regional syntheses, TRENDY (Trends in net land atmosphere carbon exchanges), and WETCHIMP (Wetland and Wetland CH4 Inter-comparison of Models Project) – we provide a baseline of terrestrial carbon cycle uncertainty, defined as the multi-model standard deviation (o) for each quantity that follows. Mean annual absolute uncertainty was largest for soil carbon (14.0±9.2 kgCm−2), then gross primary production (GPP) (0.22±0.50 kgCm−2 yr−1), ecosystem respiration (Re) (0.23±0.38 kgCm−2 yr−1), net primary production (NPP) (0.14±0.33 kgCm−2 yr−1), autotrophic respiration (Ra) (0.09±0.20 kgCm−2 yr−1), heterotrophic respiration (Rh) (0.14±0.20 kgCm−2 yr−1), net ecosystem exchange (NEE) (−0.01±0.19 kgCm−2 yr−1), and CH4 flux
(2.52±4.02 g CH4 m−2 yr−1). There were no consistent spatial
patterns in the larger Alaskan Arctic and boreal regional
carbon stocks and fluxes, with some models showing NEE
for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic and larger boreal region
TOLL-LIKE RECEPTOR-4 (TLR4) GENE POLYMORPHISM IN HARINGHATA BLACK CHICKEN BREED
The experiment was conducted on Haringhata Black Chicken breed to investigate the polymorphism of
exon-2 of Toll-Like Receptor-4 gene. Genomic DNA extracted from 82 birds was used for Polymerase Chain Reaction
(PCR). Amplified polymerase chain reaction (PCR) product (248bp) of exon-2 of TLR4 gene revealed two types of SSCP
banding pattern arbitrarily assigned as EF and FF genotypes on 10 percent polyacrylamide gel. The genotype frequencies
were found to be 0.634 for EF and 0.366 for FF genotype with respect to exon-2 of TLR4 gene. The frequencies of E and
F alleles were estimated as 0.317 and 0.683, respectively. The calculated Chi square value revealed that the population
was not in Hardy Weinberg Equilibrium with respect to TLR4 gene in Haringhata Black Chicken
Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV
We report the STAR measurement of Phi meson production in Au+Au and p+p
collisions at sqrt (s)=200 GeV. Using the event mixing technique, the Phi
spectra and yields are obtained at mid-rapidity for five centrality bins in
Au+Au collisions and for non-singly-diffractive p+p collisions. It is found
that the Phi transverse momentum distributions from Au+Au collisions are better
fitted with a single-exponential while the p+p spectrum is better described by
a double-exponential distribution. The measured nuclear modification factors
indicate that Phi production in central Au+Au collisions is suppressed relative
to peripheral collisions when scaled by the number of binary collisions. The
systematics of versus centrality and the constant Phi/K- ratio versus beam
species, centrality, and collision energy rule out kaon coalescence as the
dominant mechanism for Phi production.Comment: 6 pages, 3 figures, submitted to Phys. Rev. Let
Azimuthal anisotropy at RHIC: the first and fourth harmonics
We report the first observations of the first harmonic (directed flow, v_1),
and the fourth harmonic (v_4), in the azimuthal distribution of particles with
respect to the reaction plane in Au+Au collisions at the Relativistic Heavy Ion
Collider (RHIC). Both measurements were done taking advantage of the large
elliptic flow (v_2) generated at RHIC. From the correlation of v_2 with v_1 it
is determined that v_2 is positive, or {\it in-plane}. The integrated v_4 is
about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)
harmonics upper limits on the magnitudes are reported.Comment: 6 pages with 3 figures, as accepted for Phys. Rev. Letters The data
tables are at
http://www.star.bnl.gov/central/publications/pubDetail.php?id=3
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at GeV
Identified mid-rapidity particle spectra of , , and
from 200 GeV p+p and d+Au collisions are reported. A
time-of-flight detector based on multi-gap resistive plate chamber technology
is used for particle identification. The particle-species dependence of the
Cronin effect is observed to be significantly smaller than that at lower
energies. The ratio of the nuclear modification factor () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of in minimum-bias d+Au
collisions is found to be a factor of 2 lower than that in Au+Au collisions,
indicating that the Cronin effect alone is not enough to account for the
relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from
transverse momentum 1.8 GeV/c to 3. GeV/
Single Spin Asymmetry in Polarized Proton-Proton Elastic Scattering at GeV
We report a high precision measurement of the transverse single spin
asymmetry at the center of mass energy GeV in elastic
proton-proton scattering by the STAR experiment at RHIC. The was measured
in the four-momentum transfer squared range \GeVcSq, the region of a significant interference between the
electromagnetic and hadronic scattering amplitudes. The measured values of
and its -dependence are consistent with a vanishing hadronic spin-flip
amplitude, thus providing strong constraints on the ratio of the single
spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated
by the Pomeron amplitude at this , we conclude that this measurement
addresses the question about the presence of a hadronic spin flip due to the
Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure
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