1,102 research outputs found
Water quality in Princess Charlotte Bay flood plumes and eastern Cape York Peninsula flood plume exposure: 2012-2014
The Marine Monitoring Program (MMP) undertaken in the Great Barrier Reef lagoon assesses the long-term effectiveness of the Australian and Queensland Government’s Reef Water Quality Protection Plan and the Australian Government Reef Rescue initiative. The MMP was established in 2005 to help assess the long-term status and health of Reef ecosystems and is a critical component in the assessment of regional water quality as land management practices are improved across Reef catchments. The program forms an integral part of the Reef Plan Paddock to Reef Integrated Monitoring, Modelling and Reporting Program supported through Reef Plan and Reef Rescue initiatives. This report details the sampling that has taken place under the Marine Monitoring Program in Cape Yor
Can re-entrance be observed in force induced transitions?
A large conformational change in the reaction co-ordinate and the role of the
solvent in the formation of base-pairing are combined to settle a long standing
issue {\it i.e.} prediction of re-entrance in the force induced transition of
DNA. A direct way to observe the re-entrance, i.e a strand goes to the closed
state from the open state and again to the open state with temperature, appears
difficult to be achieved in the laboratory. An experimental protocol (in direct
way) in the constant force ensemble is being proposed for the first time that
will enable the observation of the re-entrance behavior in the
force-temperature plane. Our exact results for small oligonucleotide that forms
a hairpin structure provide the evidence that re-entrance can be observed.Comment: 12 pages and 5 figures (RevTex4). Accepted in Europhys Lett. (2009
The SPLASH Survey: Kinematics of Andromeda's Inner Spheroid
The combination of large size, high stellar density, high metallicity, and
Sersic surface brightness profile of the spheroidal component of the Andromeda
galaxy (M31) within R_proj ~ 20 kpc suggest that it is unlike any subcomponent
of the Milky Way. In this work we capitalize on our proximity to and external
view of M31 to probe the kinematical properties of this "inner spheroid." We
employ a Markov chain Monte Carlo (MCMC) analysis of resolved stellar
kinematics from Keck/DEIMOS spectra of 5651 red giant branch stars to
disentangle M31's inner spheroid from its stellar disk. We measure the mean
velocity and dispersion of the spheroid in each of five spatial bins after
accounting for a locally cold stellar disk as well as the Giant Southern Stream
and associated tidal debris. For the first time, we detect significant spheroid
rotation (v_rot ~ 50 km/s) beyond R_proj ~ 5 kpc. The velocity dispersion
decreases from about 140 km/s at R_proj = 7 kpc to 120 km/s at R_proj = 14 kpc,
consistent to 2 sigma with existing measurements and models. We calculate the
probability that a given star is a member of the spheroid and find that the
spheroid has a significant presence throughout the spatial extent of our
sample. Lastly, we show that the flattening of the spheroid is due to velocity
anisotropy in addition to rotation. Though this suggests that the inner
spheroid of M31 more closely resembles an elliptical galaxy than a typical
spiral galaxy bulge, it should be cautioned that our measurements are much
farther out (2 - 14 r_eff) than for the comparison samples.Comment: Accepted for publication in Ap
Internal Stellar Kinematics of M32 from the SPLASH Survey: Dark Halo Constraints
As part of the SPLASH survey of the Andromeda (M31) system, we have obtained Keck/DEIMOS spectra of the compact elliptical (cE) satellite M32. This is the first resolved-star kinematical study of any cE galaxy. In contrast to most previous kinematical studies that extended out to r≾30" ~ 1 r^(eff) I ~ 100 pc, we measure the rotation curve and velocity dispersion profile out to r ~ 250" and higher order Gauss-Hermite moments out to r ~ 70". We achieve this by combining integrated-light spectroscopy at small radii (where crowding/blending are severe) with resolved stellar spectroscopy at larger radii, using spatial and kinematical information to account statistically for M31 contamination. The rotation curve and velocity dispersion profile extend well beyond the radius (r ~ 150") where the isophotes are distorted. Unlike NGC 205, another close dwarf companion of M31, M32's kinematics appear regular and symmetric and do not show obvious sharp gradients across the region of isophotal elongation and twists. We interpret M31's kinematics using three-integral axisymmetric dynamical equilibrium models constructed using Schwarzschild's orbit superposition technique. Models with a constant mass-to-light ratio can fit the data remarkably well. However, since such a model requires an increasing tangential anisotropy with radius, invoking the presence of an extended dark halo may be more plausible. Such an extended dark halo is definitely required to bind a half-dozen fast-moving stars observed at the largest radii, but these stars may not be an equilibrium component of M32
Effectiveness of a comprehensive mental skills curriculum in enhancing surgical performance: Results of a randomized controlled trial
INTRODUCTION:
We hypothesized that the implementation of a novel mental skills curriculum (MSC) during laparoscopic simulator training would improve mental skills and performance, and decrease stress.
METHODS:
Sixty volunteer novices were randomized into intervention and control groups. All participants received FLS training while the intervention group also participated in the MSC. Skill transfer and retention were assessed on a live porcine model after training and 2 months later, respectively. Performance was assessed using the Test of Performance Strategies-2 (TOPS-2) for mental skills, FLS metrics for laparoscopic performance, and the State Trait Anxiety Inventory (STAI-6) and heart rate (HR) for stress.
RESULTS:
Fifty-five participants (92%) completed training and the transfer test, and 46 (77%) the retention test. There were no significant differences between groups at baseline. Compared to controls the intervention group significantly improved their mental skill use, demonstrated higher laparoscopic skill improvement during retention, and reported less stress during the transfer test.
CONCLUSIONS:
The MSC implemented in this study effectively enhanced participants' mental skill use, reduced cognitive stress in the operating room with a small impact on laparoscopic performance
Body composition and body fat distribution are related to cardiac autonomic control in non-alcoholic fatty liver disease patients
BACKGROUND/OBJECTIVES: Heart rate recovery (HRR), a cardiac autonomic control marker, was shown to be related to body composition (BC), yet this was not tested in non-alcoholic fatty liver disease (NAFLD) patients. The aim of this study was to determine if, and to what extent, markers of BC and body fat (BF) distribution are related to cardiac autonomic control in NAFLD patients. SUBJECTS/METHODS: BC was assessed with dual-energy X-ray absorptiometry in 28 NAFLD patients (19 men, 51±13 years, and 9 women, 47±13 years). BF depots ratios were calculated to assess BF distribution. Subjects’ HRR was recorded 1 (HRR1) and 2 min (HRR2) immediately after a maximum graded exercise test.
RESULTS: BC and BF distribution were related to HRR; particularly weight, trunk BF and trunk BF-to-appendicular BF ratio showed a negative relation with HRR1 (r 1⁄4 0.613, r 1⁄4 0.597 and r 1⁄4 0.547, respectively, Po0.01) and HRR2 (r 1⁄4 0.484, r 1⁄4 0.446, Po0.05, and r 1⁄4 0.590, Po0.01, respectively). Age seems to be related to both HRR1 and HRR2 except when controlled for BF distribution. The preferred model in multiple regression should include trunk BF-to-appendicular BF ratio and BF to predict HRR1 (r2 1⁄4 0.549; Po0.05), and trunk BF-to-appendicular BF ratio alone to predict HRR2 (r2 1⁄4 0.430; Po0.001).
CONCLUSIONS: BC and BF distribution were related to HRR in NAFLD patients. Trunk BF-to-appendicular BF ratio was the best independent predictor of HRR and therefore may be best related to cardiovascular increased risk, and possibly act as a mediator in age-related cardiac autonomic control variation.info:eu-repo/semantics/publishedVersio
Measurement of Muon Antineutrino Quasi-Elastic Scattering on a Hydrocarbon Target at E_{\nu} ~ 3.5 GeV
We have isolated muon anti-neutrino charged-current quasi-elastic
interactions occurring in the segmented scintillator tracking region of the
MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the
flux-averaged differential cross-section, d{\sigma}/dQ^2, and compare to
several theoretical models of quasi-elastic scattering. Good agreement is
obtained with a model where the nucleon axial mass, M_A, is set to 0.99 GeV/c^2
but the nucleon vector form factors are modified to account for the observed
enhancement, relative to the free nucleon case, of the cross-section for the
exchange of transversely polarized photons in electron-nucleus scattering. Our
data at higher Q^2 favor this interpretation over an alternative in which the
axial mass is increased.Comment: 8 pages, 5 figures. Added correlation between neutrino and
anti-neutrino results in ancillary text files (CSV
The Panchromatic Hubble Andromeda Treasury I: Bright UV Stars in the Bulge of M31
As part of the Panchromatic Hubble Andromeda Treasury (PHAT) multi-cycle
program, we observed a 12' \times 6.5' area of the bulge of M31 with the
WFC3/UVIS filters F275W and F336W. From these data we have assembled a sample
of \sim4000 UV-bright, old stars, vastly larger than previously available. We
use updated Padova stellar evolutionary tracks to classify these hot stars into
three classes: Post-AGB stars (P-AGB), Post-Early AGB (PE-AGB) stars and
AGB-manqu\'e stars. P-AGB stars are the end result of the asymptotic giant
branch (AGB) phase and are expected in a wide range of stellar populations,
whereas PE-AGB and AGB-manqu\'e (together referred to as the hot
post-horizontal branch; HP-HB) stars are the result of insufficient envelope
masses to allow a full AGB phase, and are expected to be particularly prominent
at high helium or {\alpha} abundances when the mass loss on the RGB is high.
Our data support previous claims that most UV-bright sources in the bulge are
likely hot (extreme) horizontal branch stars (EHB) and their progeny. We
construct the first radial profiles of these stellar populations, and show that
they are highly centrally concentrated, even more so than the integrated UV or
optical light. However, we find that this UV-bright population does not
dominate the total UV luminosity at any radius, as we are detecting only the
progeny of the EHB stars that are the likely source of the UVX. We calculate
that only a few percent of MS stars in the central bulge can have gone through
the HP-HB phase and that this percentage decreases strongly with distance from
the center. We also find that the surface density of hot UV-bright stars has
the same radial variation as that of low-mass X-ray binaries. We discuss age,
metallicity, and abundance variations as possible explanations for the observed
radial variation in the UV-bright population.Comment: Accepted for publication in Ap
Local Group Dwarf Elliptical Galaxies: II. Stellar Kinematics to Large Radii in NGC 147 and NGC 185
We present kinematic and metallicity profiles for the M31 dwarf elliptical
(dE) satellite galaxies NGC 147 and NGC 185. The profiles represent the most
extensive spectroscopic radial coverage for any dE galaxy, extending to a
projected distance of eight half-light radii (8 r_eff = 14'). We achieve this
coverage via Keck/DEIMOS multislit spectroscopic observations of 520 and 442
member red giant branch stars in NGC 147 and NGC 185, respectively. In contrast
to previous studies, we find that both dEs have significant internal rotation.
We measure a maximum rotational velocity of 17+/-2 km/s for NGC 147 and 15+/-5
km/s for NGC 185. The velocity dispersions decrease gently with radius with an
average dispersion of 16+/-1 km/s for NGC 147 and 24+/-1 km/s for NGC 185. Both
dEs have internal metallicity dispersions of 0.5 dex, but show no evidence for
a radial metallicity gradient. We construct two-integral axisymmetric dynamical
models and find that the observed kinematical profiles cannot be explained
without modest amounts of non-baryonic dark matter. We measure central
mass-to-light ratios of ML_V = 4.2+/-0.6 and ML_V = 4.6+/-0.6 for NGC 147 and
NGC 185, respectively. Both dE galaxies are consistent with being primarily
flattened by their rotational motions, although some anisotropic velocity
dispersion is needed to fully explain their observed shapes. The velocity
profiles of all three Local Group dEs (NGC 147, NGC 185 and NGC 205) suggest
that rotation is more prevalent in the dE galaxy class than previously assumed,
but is often manifest only at several times the effective radius. Since all dEs
outside the Local Group have been probed to only inside the effective radius,
this opens the door for formation mechanisms in which dEs are transformed or
stripped versions of gas-rich rotating progenitor galaxies.Comment: 16 pages, 7 figures. accepted to A
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