8,496 research outputs found
Parity-Projected Shell Model Monte Carlo Level Densities for fp-shell Nuclei
We calculate parity-dependent level densities for the even-even isotopes
58,62,66 Fe and 58 Ni and the odd-A nuclei 59 Ni and 65 Fe using the Shell
Model Monte Carlo method. We perform these calculations in the complete fp-gds
shell-model space using a pairing+quadrupole residual interaction. We find
that, due to pairing of identical nucleons, the low-energy spectrum is
dominated by positive parity states. Although these pairs break at around the
same excitation energy in all nuclei, the energy dependence of the ratio of
negative-to-positive parity level densities depends strongly on the particular
nucleus of interest. We find equilibration of both parities at noticeably lower
excitation energies for the odd-A nuclei 59 Ni and 65 Fe than for the
neighboring even-even nuclei 58 Ni and 66 Fe.Comment: 5 pages, 4 figures, submitted to Phys. Rev.
The Spitzer South Pole Telescope Deep Field Survey: Linking galaxies and halos at z=1.5
We present an analysis of the clustering of high-redshift galaxies in the
recently completed 94 deg Spitzer-SPT Deep Field survey. Applying flux and
color cuts to the mid-infrared photometry efficiently selects galaxies at
in the stellar mass range , making this
sample the largest used so far to study such a distant population. We measure
the angular correlation function in different flux-limited samples at scales
(corresponding to physical distances Mpc) and
thereby map the one- and two-halo contributions to the clustering. We fit halo
occupation distributions and determine how the central galaxy's stellar mass
and satellite occupation depend on the halo mass. We measure a prominent peak
in the stellar-to-halo mass ratio at a halo mass of , 4.5 times higher than the value. This supports
the idea of an evolving mass threshold above which star formation is quenched.
We estimate the large-scale bias in the range and the satellite
fraction to be , showing a clear evolution compared to
. We also find that, above a given stellar mass limit, the fraction of
galaxies that are in similar mass pairs is higher at than at . In
addition, we measure that this fraction mildly increases with the stellar mass
limit at , which is the opposite of the behavior seen at low-redshift.Comment: 32 pages, 22 figures. Published in MNRA
Maintenance inhaler therapy preferences of patients with asthma or chronic obstructive pulmonary disease:a discrete choice experiment
Background A variety of maintenance inhaler therapies are available to treat asthma and COPD. Patient-centric treatment choices require understanding patient preferences for the alternative therapies. Methods A self-completed web-based discrete choice experiment was conducted to elicit patient preferences for inhaler device and medication attributes. Selection of attributes was informed by patient focus groups and literature review. Results The discrete choice experiment was completed by 810 patients with asthma and 1147 patients with COPD. Patients with asthma most valued decreasing the onset of action from 30 to 5 min, followed by reducing yearly exacerbations from 3 to 1. Patients with COPD most and equally valued decreasing the onset of action from 30 to 5 min and reducing yearly exacerbations from 3 to 1. Both patients with asthma and patients with COPD were willing to accept an additional exacerbation in exchange for a 15 min decrease in onset of action and a longer onset of action in exchange for a lower risk of adverse effects from inhaled corticosteroids. Patients with asthma and COPD valued once-daily over twice-daily dosing, pressurised inhalers over dry powder inhalers and non-capsule priming over single-use capsules, although these attributes were not valued as highly as faster onset of action or reduced exacerbations. Conclusions The most important maintenance inhaler attributes for patients with asthma and COPD were fast onset of symptom relief and a lower rate of exacerbations. Concerns about safety of inhaled corticosteroids and device convenience also affected patient preferences but were less important
Dual-combination maintenance inhaler preferences in asthma and chronic obstructive pulmonary disease:A patient-centered benefit-risk assessment
Background: A variety of dual-combination maintenance inhalers are used to treat asthma and chronic obstructive pulmonary disease (COPD). Understanding patient preferences for treatment attributes may help select an optimal treatment from the patient perspective. Methods: Patient preferences for maintenance inhaler device and medication attributes were elicited through a discrete choice experiment and used in benefit-risk assessments to calculate predicted choice probabilities (PrCPs) for 14 dual-combination maintenance inhalers in four treatment classes: lower- and higher-dose inhaled corticosteroid (ICS)/long-acting beta agonist (LABA) inhalers for asthma, and ICS/LABA and long-acting muscarinic antagonist (LAMA)/LABA inhalers for COPD. Results: For all treatment classes, reduced exacerbations and faster onset of action were the most important attributes. For all classes, patients were willing to tolerate an extra yearly exacerbation to decrease the medication's onset of action from 30 to 5 min. For patients with asthma using lower-dose ICS/LABA (n = 497), budesonide/formoteml fumarate dihydrate (80 mu g/4.5 mu g) pressurized metered-dose inhaler (pMDI) had the highest PrCP (28.4%), and for those using a higher-dose ICS/LABA (n = 285), PrCPs were highest for mometasone furoate/formoterol fumarate dihydrate (200 mu g/5 mu g) pMDI (27.0%) and budesonide/formoterol fumarate dihydrate (160 mu g/4.5 mu g) pMDI (26.9%). For patients with COPD using an ICS/LABA (n = 574), budesonide/ formoterol fumarate dihydrate (160 mu g/4.5 mu g) pMDI had the highest PrCP (56.6%), and for those using a LAMA/LABA inhaler (n = 217), tiotropium/olodaterol (2.5 mu g/2.5 mu g) soft mist inhaler had the highest PrCP (42.3%). Conclusions: Patient preference data for maintenance inhaler attributes can be used to identify a preference order of inhalers in different treatment classes
Capture-Recapture Reveals Heterogeneity in Habitat-Specific Mongoose Densities and Spatiotemporal Variability in Trapping Success in St. Kitts, West Indies
The small Indian mongoose (Urva auropunctata) is a non-native invasive species across the Caribbean and a rabies reservoir on at least four islands in the region. Although previous studies reported mongoose density estimates in their non-native range, the variability in trapping designs, study seasonality, and analytical methods among studies precludes direct comparisons. This study is the first to report mongoose densities for the island of St. Kitts, West Indies. Our objective was to quantify mongoose densities across four habitats characteristic for the island. High capture and recapture rates in this study resulted in detailed estimates of spatial heterogeneity in mongoose densities, ranging from 0.53 (CI95: 0.46–0.61) mongooses/ha in suburban habitat to 5.85 (CI95: 4.42–7.76) mongooses/ha in nearby dry forest. Estimates were robust to the estimation method used (correlation among methods, r \u3e 0.9). Female-biased sex ratios estimated from fall season versus mostly unbiased sex ratios estimated from summer season suggests seasonality in capture success resulting from differences in sex-specific activity patterns of mongooses. We found no effect of habitat characteristics, at the scale of trap placements, associated with mongoose capture success
The kinematic footprints of five stellar streams in Andromeda's halo
(abridged) We present a spectroscopic analysis of five stellar streams (`A',
`B', `Cr', `Cp' and `D') as well as the extended star cluster, EC4, which lies
within streamC, all discovered in the halo of M31 from our CFHT/MegaCam survey.
These spectroscopic results were initially serendipitous, making use of our
existing observations from the DEep Imaging Multi-Object Spectrograph mounted
on the Keck II telescope, and thereby emphasizing the ubiquity of tidal streams
that account for ~70% of the M31 halo stars in the targeted fields. Subsequent
spectroscopy was then procured in streamCr/p and streamD to trace the velocity
gradient along the streams. For the cluster EC4, candidate member stars with
average [Fe/H]~-1.4 (Fe/H_spec=-1.6), are found at v_{hel}=-285 km/s suggesting
it could be related to streamCp. No similarly obvious cold kinematic candidate
is found for streamD, although candidates are proposed in both of two
spectroscopic pointings along the stream (both at -400 km/s). Spectroscopy near
the edge of streamB suggests a likely kinematic detection, while a candidate
kinematic detection of streamA is found (plausibly associated to M33 rather
than M31). The low dispersion of the streams in kinematics, physical thickness,
and metallicity makes it hard to reconcile with a scenario whereby these stream
structures as an ensemble are related to the giant southern stream. We conclude
that the M31 stellar halo is largely made up of multiple kinematically cold
streams.Comment: 19 pages, 12 figures, accepted in MNRAS. High resolution version,
with fig10 here: http://www.ast.cam.ac.uk/~schapman/streams.pd
Annual variation in the levels of transcripts of sex-specific genes in the mantle of the common mussel, Mytilus edulis
Mytilus species are used as sentinels for the assessment of environmental health but sex or stage in the reproduction cycle is rarely considered even though both parameters are likely to influence responses to pollution. We have validated the use of a qPCR assay for sex identification and related the levels of transcripts to the reproductive cycle. A temporal study of mantle of Mytilus edulis found transcripts of male-specific vitelline coat lysin (VCL) and female-specific vitelline envelope receptor for lysin (VERL) could identify sex over a complete year. The levels of VCL/VERL were proportional to the numbers of sperm/ova and are indicative of the stage of the reproductive cycle. Maximal levels of VCL and VERL were found in February 2009 declining to minima between July - August before increasing and re-attaining a peak in February 2010. Water temperature may influence these transitions since they coincide with minimal water temperature in February and maximal temperature in August. An identical pattern of variation was found for a cryptic female-specific transcript (H5) but a very different pattern was observed for oestrogen receptor 2 (ER2). ER2 varied in a sex-specific way with male > female for most of the cycle, with a female maxima in July and a male maxima in December. Using artificially spawned animals, the transcripts for VCL, VERL and H5 were shown to be present in gametes and thus their disappearance from mantle is indicative of spawning. VCL and VERL are present at equivalent levels in February and July-August but during gametogenesis (August to January) and spawning (March to June) VCL is present at lower relative amounts than VERL. This may indicate sex-specific control mechanisms for these processes and highlight a potential pressure point leading to reduced reproductive output if environmental factors cause asynchrony to gamete maturation or release
The Recent Stellar Archeology of M31 - The Nearest Red Disk Galaxy
We examine the star-forming history (SFH) of the M31 disk during the past few
hundred Myr. The luminosity functions (LFs) of main sequence stars at distances
R_GC > 21 kpc (i.e. > 4 disk scale lengths) are matched by models that assume a
constant star formation rate (SFR). However, at smaller R_GC the LFs suggest
that during the past ~10 Myr the SFR was 2 - 3 times higher than during the
preceding ~100 Myr. The rings of cool gas that harbor a significant fraction of
the current star-forming activity are traced by stars with ages ~100 Myr,
indicating that (1) these structures have ages of at least 100 Myr, and (2)
stars in these structures do not follow the same relation between age and
random velocity as their counterparts throughout the disks of other spiral
galaxies, probably due to the inherently narrow orbital angular momentum
distribution of the giant molecular clouds in these structures. The
distribution of evolved red stars is not azimuthally symmetric, in the sense
that their projected density along the north east segment of the major axis is
roughly twice that on the opposite side of the galaxy. The north east arm of
the major axis thus appears to be a fossil star-forming area that dates to
intermediate epochs. Such a structure may be the consequence of interactions
with a companion galaxy.Comment: To appear in The Astrophysical Journa
Response of Horticultural Soil Microbiota to Different Fertilization Practices
Environmentally friendly agricultural production necessitates manipulation of microbe–plant interactions, requiring a better understanding of how farming practices influence soil microbiota. We studied the effect of conventional and organic treatment on soil bacterial richness, composition, and predicted functional potential. 16S rRNA sequencing was applied to soils from adjacent plots receiving either a synthetic or organic fertilizer, where two crops were grown within treatment, homogenizing for differences in soil properties, crop, and climate. Conventional fertilizer was associated with a decrease in soil pH, an accumulation of Ag, Mn, As, Fe, Co, Cd, and Ni; and an enrichment of ammonia oxidizers and xenobiotic compound degraders (e.g., Candidatus Nitrososphaera, Nitrospira, Bacillus, Pseudomonas). Soils receiving organic fertilization were enriched in Ti (crop biostimulant), N, and C cycling bacteria (denitrifiers, e.g., Azoarcus, Anaerolinea; methylotrophs, e.g., Methylocaldum, Methanosarcina), and disease-suppression (e.g., Myxococcales). Some predicted functions, such as glutathione metabolism, were slightly, but significantly enriched after a one-time manure application, suggesting the enhancement of sulfur regulation, nitrogen-fixing, and defense of environmental stressors. The study highlights that even a single application of organic fertilization is enough to originate a rapid shift in soil prokaryotes, responding to the differential substrate availability by promoting soil health, similar to recurrent applications.This work was supported by the Earth Microbiome Project; the METAMAHA project funded by the Basque Government’s Department of Industry, Trade, and Tourism (SAIOTEK program; S-PE13UN130); and IT1014-16 and IT1213-19 Consolidated Research Group Projects
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