1,685 research outputs found
Intraprostatic Injection of Alcohol Gel for the Treatment of Benign Prostatic Hyperplasia: Preliminary Clinical Results
Benign prostatic hyperplasia (BPH) is one of the most common diseases ailing older men. Office-based procedures offer the advantage of being more effective than medications, while limiting the adverse effects, cost, and recovery of surgery. This study presents preliminary data on a new procedure that utilizes intraprostatic alcohol gel injection to ablate prostatic tissue. The purpose of this study is to evaluate the feasibility of using this gel as a treatment for BPH
Local brain connectivity and associations with gender and age
ABSTRACTRegional homogeneity measures synchrony of resting-state brain activity in neighboring voxels, or local connectivity. The effects of age and gender on local connectivity in healthy subjects are unknown. We performed regional homogeneity analyses on resting state BOLD time series data acquired from 58 normal, healthy participants, ranging in age from 11 to 35 (mean 18.1±5.0 years, 32 males). Regional homogeneity was found to be highest for gray matter, with brain regions within the default mode network having the highest local connectivity values. There was a general decrease in regional homogeneity with age with the greatest reduction seen in the anterior cingulate and temporal lobe. Greater female local connectivity in the right hippocampus and amygdala was also noted, regardless of age. These findings suggest that local connectivity at the millimeter scale decreases during development as longer connections are formed, and underscores the importance of examining gender differences in imaging studies of healthy and clinical populations
Dark Coupling and Gauge Invariance
We study a coupled dark energy-dark matter model in which the energy-momentum
exchange is proportional to the Hubble expansion rate. The inclusion of its
perturbation is required by gauge invariance. We derive the linear perturbation
equations for the gauge invariant energy density contrast and velocity of the
coupled fluids, and we determine the initial conditions. The latter turn out to
be adiabatic for dark energy, when assuming adiabatic initial conditions for
all the standard fluids. We perform a full Monte Carlo Markov Chain likelihood
analysis of the model, using WMAP 7-year data.Comment: 16 pages, 2 figures, version accepted for publication in JCA
On the oxygen and nitrogen chemical abundances and the evolution of the "green pea" galaxies
We have investigated the oxygen and nitrogen chemical abundances in extremely
compact star-forming galaxies with redshifts between 0.11-0.35, popularly
referred to as "green peas". Direct and strong-line methods sensitive to the
N/O ratio applied to their SDSS spectra reveals that these systems are genuine
metal-poor galaxies, with mean oxygen abundances 20% solar. At a given
metallicity these galaxies display systematically large N/O ratios compared to
normal galaxies, which can explain the strong difference between our
metallicities measurements and previous ones. While their N/O ratios follow the
relation with stellar mass of local star-forming galaxies in the SDSS, we find
that the mass--metallicity relation of the "green peas" is offset \ga0.3 dex
to lower metallicities. We argue that recent interaction-induced inflow of gas,
possibly coupled with a selective metal-rich gas loss, driven by supernova
winds, may explain our findings and the known galaxy properties, namely high
specific star formation rates, extreme compactness, and disturbed optical
morphologies. The "green pea" galaxy properties seem to be not common in the
nearby Universe, suggesting a short and extreme stage of their evolution.
Therefore, these galaxies may allow us to study in great detail many processes,
such as starburst activity and chemical enrichment, under physical conditions
approaching those in galaxies at higher redshifts.Comment: 8 pages, 3 Figures, ApJ Letters in press. Proof version with
correction
Unusually Luminous Giant Molecular Clouds in the Outer Disk of M33
We use high spatial resolution (~7pc) CARMA observations to derive detailed
properties for 8 giant molecular clouds (GMCs) at a galactocentric radius
corresponding to approximately two CO scale lengths, or ~0.5 optical radii
(r25), in the Local Group spiral galaxy M33. At this radius, molecular gas
fraction, dust-to-gas ratio and metallicity are much lower than in the inner
part of M33 or in a typical spiral galaxy. This allows us to probe the impact
of environment on GMC properties by comparing our measurements to previous data
from the inner disk of M33, the Milky Way and other nearby galaxies. The outer
disk clouds roughly fall on the size-linewidth relation defined by
extragalactic GMCs, but are slightly displaced from the luminosity-virial mass
relation in the sense of having high CO luminosity compared to the inferred
virial mass. This implies a different CO-to-H2 conversion factor, which is on
average a factor of two lower than the inner disk and the extragalactic
average. We attribute this to significantly higher measured brightness
temperatures of the outer disk clouds compared to the ancillary sample of GMCs,
which is likely an effect of enhanced radiation levels due to massive star
formation in the vicinity of our target field. Apart from brightness
temperature, the properties we determine for the outer disk GMCs in M33 do not
differ significantly from those of our comparison sample. In particular, the
combined sample of inner and outer disk M33 clouds covers roughly the same
range in size, linewidth, virial mass and CO luminosity than the sample of
Milky Way GMCs. When compared to the inner disk clouds in M33, however, we find
even the brightest outer disk clouds to be smaller than most of their inner
disk counterparts. This may be due to incomplete sampling or a potentially
steeper cloud mass function at larger radii.Comment: Accepted for Publication in ApJ; 7 pages, 4 figure
The Color-Magnitude Effect in Early-Type Cluster Galaxies
We present the analysis of the color-magnitude relation (CMR) for a sample of
57 X-ray detected Abell clusters within the redshift interval 0.02 <= z <=
0.18. We use the B-R vs R color-magnitude plane to establish that the CMR is
present in all our low-redshift clusters and can be parameterized by a single
straight line.We find that the CMRs for this large cluster sample of different
richness and cluster types are consistent with having universal properties. The
k-corrected color of the individual CMRs in the sample at a fixed absolute
magnitude have a small intrinsic dispersion of ~0.05 mag. The slope of the CMR
is consistent with being the same for all clusters, with the variations
entirely accountable by filter band shifting effects. We determine the mean of
the dispersion of the 57 CMRs to be 0.074 mag, with a small rms scatter of
0.026 mag. However, a modest amount of the dispersion arises from photometric
measurement errors and possible background cluster superpositions; and the
derived mean dispersion is an upper limit. Models which explain the CMR in
terms of metallicity and passive evolution can naturally reproduce the observed
behavior of the CMR in this paper. The observed properties of the CMR are
consistent with models in which the last episode of significant star formation
in cluster early-type galaxies occurred significantly more than ~3 Gyr ago, and
that the core set of early-type galaxies in clusters were formed more than 7
Gyr ago. (abridged)Comment: Accepted ApJ, 17 pages, 4 figures (high-res fig 1 available in ApJ
version
ChaLearn Joint Contest on Multimedia Challenges Beyond Visual Analysis: An overview
This paper provides an overview of the Joint Contest on Multimedia Challenges Beyond Visual Analysis. We organized an academic competition that focused on four problems that require effective processing of multimodal information in order to be solved. Two tracks were devoted to gesture spotting and recognition from RGB-D video, two fundamental problems for human computer interaction. Another track was devoted to a second round of the first impressions challenge of which the goal was to develop methods to recognize personality traits from short video clips. For this second round we adopted a novel collaborative-competitive (i.e., coopetition) setting. The fourth track was dedicated to the problem of video recommendation for improving user experience. The challenge was open for about 45 days, and received outstanding participation: almost 200 participants registered to the contest, and 20 teams sent predictions in the final stage. The main goals of the challenge were fulfilled: the state of the art was advanced considerably in the four tracks, with novel solutions to the proposed problems (mostly relying on deep learning). However, further research is still required. The data of the four tracks will be available to allow researchers to keep making progress in the four tracks
Biofuel subsidies and international trade
This paper explores optimal biofuel subsidies in a general equilibrium trade model. The focus is on the production of biofuels such as corn-based ethanol, which diverts corn from use as food. In the small-country case, when the tax on crude is not available as a policy option, a second-best biofuel subsidy may or may not be positive. In the large-country case, the twin objectives of pollution reduction and terms-of-trade improvement justify a combination of crude tax and biofuel subsidy for the food exporter. Finally, we show that when both nations engage in biofuel policies, the terms-of-trade effects encourage the Nash equilibrium subsidy to be positive (negative) for the food exporting (importing) nation
The Slope of the Cluster Elliptical Red Sequence: A Probe of Cluster Evolution
The current formation models for cluster elliptical galaxies which
incorporate a mechanism for the metallicity enhancement of massive ellipticals
predict a change in the observed slope of the red sequence of ellipticals as a
function of redshift. This change occurs primarily because the metal-rich
galaxies become redder faster than the metal-poorer galaxies with increasing
age. This effect is most pronounced within ~ 4 Gyr of formation. Observations
of the change of the slope of the red sequence with redshift may thus be used
to constrain the formation epoch for galaxy clusters. We examine the red
sequence of cluster ellipticals using publicly available HST imaging data for a
set of six 0.75>z>0.2 clusters, and a sample of 44 Abell clusters at z<0.15
imaged with the KPNO 0.9 m. We compare the derived slopes of the red sequences
with a set of cluster-elliptical evolution models and find good agreement. We
demonstrate that such a comparison provides a useful constraint on the
formation epoch for clusters, which can be made independently from
considerations of absolute color evolution and scatter in the red sequence.
From our initial comparison of the observed and model slopes as a function of
redshift, we conclude, conservatively, that most of the elliptical galaxies in
the cores of clusters must form at z>2.0, and that these galaxies are coeval
and passively evolving.Comment: 14 pages, 5 figures, Accepted for publication in Ap
High Voltage Mg-Doped Na 0.67 Ni 0.3â x Mg x Mn 0.7 O 2 ( x = 0.05, 0.1) Na-Ion Cathodes with Enhanced Stability and Rate Capability
Magnesium substituted P2-structure Na0.67Ni0.3Mn0.7O2 materials have been prepared by a facile solid-state method and investigated as cathodes in sodium-ion batteries. The Mg-doped materials described here were characterized by X-ray diffraction (XRD), 23Na solid-state nuclear magnetic resonance (SS-NMR), and scanning electron microscopy (SEM). The electrochemical performance of the samples was tested in half cells vs Na metal at room temperature. The Mg-doped materials operate at a high average voltage of ca. 3.3 V vs Na/Na+ delivering specific capacities of âŒ120 mAh gâ1, which remain stable up to 50 cycles. Mg doping suppresses the well-known P2âO2 phase transition observed in the undoped composition by stabilizing the reversible OP4 phase during charging (during Na removal). GITT measurements showed that the Na-ion mobility is improved by 2 orders of magnitude with respect to the parent P2âNa0.67Ni0.3Mn0.7O2 material. The fast Na-ion mobility may be the cause of the enhanced rate performance
- âŠ