6,931 research outputs found
Level density and gamma strength function in 162-Dy from inelastic 3-He scattering
Complementary measurements have been performed for the level density and
gamma strength function in 162-Dy using inelastic 3-He scattering. Comparing
these results to previous measurements using the 163-Dy(3-He,alpha) reaction,
reveals that the measured quantities above 1.5 MeV do not depend significantly
on the nuclear reaction chosen.Comment: 15 pages, including 7 figure
Critical temperature for quenching of pair correlations
The level density at low spin in the 161,162-Dy and 171,172-Yb nuclei has
been extracted from primary gamma rays. The nuclear heat capacity is deduced
within the framework of the canonical ensemble. The heat capacity exhibits an
S-formed shape as a function of temperature, which is interpreted as a
fingerprint of the phase transition from a strongly correlated to an
uncorrelated phase. The critical temperature for the quenching of pair
correlations is found at Tc=0.50(4) MeV.Comment: 8 pages including 4 figures, different method to extract Tc,
different figures, text partly rewritte
Shock-induced star formation in a model of the Mice
Star formation plays an important role in the fate of interacting galaxies.
To date, most galactic simulations including star formation have used a
density-dependent star formation rule designed to approximate a Schmidt law.
Here, I present a new star formation rule which is governed by the local rate
of energy dissipation in shocks. The new and old rules are compared using
self-consistent simulations of NGC 4676; shock-induced star formation provides
a better match to the observations of this system.Comment: Submitted to MNRAS. 12 pages, 5 B&W figures, 2 color figures. See
http://www.ifa.hawaii.edu/~barnes/sisfmm.html for a version with
high-resolution figures, and
http://www.ifa.hawaii.edu/~barnes/research/interaction_models/mice/index.html
for animations of the simulation
Stellar Kinematics in the Complicated Inner Spheroid of M31: Discovery of Substructure Along the Southeastern Minor Axis and its Relationship to the Giant Southern Stream
We present the discovery of a kinematically-cold stellar population along the
SE minor axis of the Andromeda galaxy (M31) that is likely the forward
continuation of M31's giant southern stream. This discovery was made in the
course of an on-going spectroscopic survey of red giant branch (RGB) stars in
M31 using the DEIMOS instrument on the Keck II 10-m telescope. Stellar
kinematics are investigated in eight fields located 9-30 kpc from M31's center
(in projection). A likelihood method based on photometric and spectroscopic
diagnostics is used to isolate confirmed M31 RGB stars from foreground Milky
Way dwarf stars: for the first time, this is done without using radial velocity
as a selection criterion, allowing an unbiased study of M31's stellar
kinematics. The radial velocity distribution of the 1013 M31 RGB stars shows
evidence for the presence of two components. The broad (hot) component has a
velocity dispersion of 129 km/s and presumably represents M31's virialized
spheroid. A significant fraction (19%) of the population is in a narrow (cold)
component centered near M31's systemic velocity with a velocity dispersion that
decreases with increasing radial distance, from 55.5 km/s at R_proj=12 kpc to
10.6 km/s at R_proj=18 kpc. The spatial and velocity distribution of the cold
component matches that of the "Southeast shelf" predicted by the Fardal et al.
(2007) orbital model of the progenitor of the giant southern stream. The
metallicity distribution of the cold component matches that of the giant
southern stream, but is about 0.2 dex more metal rich on average than that of
the hot spheroidal component. We discuss the implications of our discovery on
the interpretation of the intermediate-age spheroid population found in this
region in recent ultra-deep HST imaging studies.Comment: 23 pages, 16 figures, 2 tables, accepted for publication in the
Astrophysical Journal. Changes from previous version: expanded discussion in
sections 4.2 and 7.2, removal of section 7.1.4 and associated figure
(discussion moved to section 7.1.2
Kepler-432: a red giant interacting with one of its two long period giant planets
We report the discovery of Kepler-432b, a giant planet ()
transiting an evolved star with an orbital period of days. Radial velocities (RVs) reveal that
Kepler-432b orbits its parent star with an eccentricity of , which we also measure independently with
asterodensity profiling (AP; ), thereby confirming
the validity of AP on this particular evolved star. The well-determined
planetary properties and unusually large mass also make this planet an
important benchmark for theoretical models of super-Jupiter formation.
Long-term RV monitoring detected the presence of a non-transiting outer planet
(Kepler-432c; days), and adaptive optics imaging revealed a nearby
(0\farcs87), faint companion (Kepler-432B) that is a physically bound M dwarf.
The host star exhibits high signal-to-noise asteroseismic oscillations, which
enable precise measurements of the stellar mass, radius and age. Analysis of
the rotational splitting of the oscillation modes additionally reveals the
stellar spin axis to be nearly edge-on, which suggests that the stellar spin is
likely well-aligned with the orbit of the transiting planet. Despite its long
period, the obliquity of the 52.5-day orbit may have been shaped by star-planet
interaction in a manner similar to hot Jupiter systems, and we present
observational and theoretical evidence to support this scenario. Finally, as a
short-period outlier among giant planets orbiting giant stars, study of
Kepler-432b may help explain the distribution of massive planets orbiting giant
stars interior to 1 AU.Comment: 22 pages, 19 figures, 5 tables. Accepted to ApJ on Jan 24, 2015
(submitted Nov 11, 2014). Updated with minor changes to match published
versio
Density-functional embedding using a plane-wave basis
The constrained electron density method of embedding a Kohn-Sham system in a
substrate system (first described by P. Cortona, Phys. Rev. B {\bf 44}, 8454
(1991) and T.A. Wesolowski and A. Warshel, J. Phys. Chem {\bf 97}, 8050 (1993))
is applied with a plane-wave basis and both local and non-local
pseudopotentials. This method divides the electron density of the system into
substrate and embedded electron densities, the sum of which is the electron
density of the system of interest. Coupling between the substrate and embedded
systems is achieved via approximate kinetic energy functionals. Bulk aluminium
is examined as a test case for which there is a strong interaction between the
substrate and embedded systems. A number of approximations to the
kinetic-energy functional, both semi-local and non-local, are investigated. It
is found that Kohn-Sham results can be well reproduced using a non-local
kinetic energy functional, with the total energy accurate to better than 0.1 eV
per atom and good agreement between the electron densities.Comment: 11 pages, 4 figure
Expression of genes associated with immunity in the endometrium of cattle with disparate postpartum uterine disease and fertility.
BACKGROUND: Contamination of the uterine lumen with bacteria is ubiquitous in cattle after parturition. Some animals develop endometritis and have reduced fertility but others have no uterine disease and readily conceive. The present study tested the hypothesis that postpartum cattle that develop persistent endometritis and infertility are unable to limit the inflammatory response to uterine bacterial infection. METHODS: Endometrial biopsies were collected several times during the postpartum period from animals that were subsequently infertile with persistent endometritis (n = 4) or had no clinical disease and conceived to first insemination (n = 4). Quantitative PCR was used to determine the expression of candidate genes in the endometrial biopsies, including the Toll-like receptor (TLR 1 to 10) family of innate immune receptors, inflammatory mediators and their cognate receptors. Selected proteins were examined by immunohistochemistry. RESULTS: The expression of genes encoding pro-inflammatory mediators such as interleukins (IL1A, IL1B and IL6), and nitric oxide synthase 2 (NOS2) were higher during the first week post partum than subsequently. During the first week post partum, there was higher gene expression in infertile than fertile animals of TLR4, the receptor for bacterial lipopolysaccharide, and the pro-inflammatory cytokines IL1A and IL1B, and their receptor IL1R2. The expression of genes encoding other Toll-like receptors, transforming growth factor beta receptor 1 (TGFBR1) or prostaglandin E2 receptors (PTGER2 and PTGER4) did not differ significantly between the animal groups. Gene expression did not differ significantly between infertile and fertile animals after the first week postpartum. However, there were higher ratios of IL1A or IL1B mRNA to the anti-inflammatory cytokine IL10, during the first week post partum in the infertile than fertile animals, and the protein products of these genes were mainly localised to the epithelium of the endometrium. CONCLUSION: Cattle may maintain fertility by limiting the inflammatory response to postpartum bacterial infection in the endometrium during the first week after parturition.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Longitudinal effects on mental health of moving to greener and less green urban areas
This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Despite growing evidence of public health benefits from urban green space there has been little longitudinal analysis. This study used panel data to explore three different hypotheses about how moving to greener or less green areas may affect mental health over time. The samples were participants in the British Household Panel Survey with mental health data (General Health Questionnaire scores) for five consecutive years, and who relocated to a different residential area between the second and third years (n = 1064; observations = 5320). Fixed-effects analyses controlled for time-invariant individual level heterogeneity and other area and individual level effects. Compared to premove mental health scores, individuals who moved to greener areas (n = 594) had significantly better mental health in all three postmove years (P = .015; P = .016; P = .008), supporting a "shifting baseline" hypothesis. Individuals who moved to less green areas (n = 470) showed significantly worse mental health in the year preceding the move (P = .031) but returned to baseline in the postmove years. Moving to greener urban areas was associated with sustained mental health improvements, suggesting that environmental policies to increase urban green space may have sustainable public health benefits.European Regional Development Fund
2007-2013European Social Fund Convergence
Programme for Cornwall and the Isles of ScillyEconomic and Social Research Counci
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