10,518 research outputs found
3-D Models of Embedded High-Mass Stars: Effects of a Clumpy Circumstellar Medium
We use 3-D radiative transfer models to show the effects of clumpy
circumstellar material on the observed infrared colors of high mass stars
embedded in molecular clouds. We highlight differences between 3-D clumpy and
1-D smooth models which can affect the interpretation of data. We discuss
several important properties of the emergent spectral energy distribution
(SED): More near-infrared light (scattered and direct from the central source)
can escape than in smooth 1-D models. The near- and mid-infrared SED of the
same object can vary significantly with viewing angle, depending on the clump
geometry along the sightline. Even the wavelength-integrated flux can vary with
angle by more than a factor of two. Objects with the same average circumstellar
dust distribution can have very different near-and mid-IR SEDs depending on the
clump geometry and the proximity of the most massive clump to the central
source.
Although clumpiness can cause similar objects to have very different SEDs,
there are some observable trends. Near- and mid-infrared colors are sensitive
to the weighted average distance of clumps from the central source and to the
magnitude of clumpy density variations (smooth-to-clumpy ratio). Far-infrared
emission remains a robust measure of the total dust mass. We present simulated
SEDs, colors, and images for 2MASS and Spitzer filters. We compare to
observations of some UCHII regions and find that 3-D clumpy models fit better
than smooth models. In particular, clumpy models with fractal dimensions in the
range 2.3-2.8, smooth to clumpy ratios of <50%, and density distributions with
shallow average radial density profiles fit the SEDs best.Comment: accepted to ApJ; version with full-res figures:
http://www.astro.virginia.edu/~ri3e/clumpy3d.pd
Use of an Inner-city Well-baby Clinic
This prospective, longitudinal investigation examined factors that influenced the use of well-baby services among a low-income, minority, high-risk group. The health belief model was used as the theoretical framework. Data were collected from 44 primiparous, black mothers attending an urban maternal child health care clinic by interviews at the first and sixth months after the birth of their infants. Analysis focused on the cues component of the model and explored the kinds of cues that influenced the mothers to bring their babies to the well-baby clinic. One important finding was that for mothers influenced by health information from radio or television, FYI commercials on television were most often reported.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72805/1/j.1525-1446.1987.tb00535.x.pd
Results of a pilot cluster randomised trial of the use of a Medication Review Tool for people taking antipsychotic medication
BACKGROUND: Government policy encourages increasing involvement of patients in their long-term care. This paper describes the development and pilot evaluation of a 'Medication Review Tool' designed to assist people to participate more effectively in discussions about antipsychotic drug treatment. METHODS: The Medication Review Tool developed consisted of a form to help patients identify pros and cons of their current antipsychotic treatment and any desired changes. It was associated with a website containing information and links about antipsychotics. For the trial, participants diagnosed with psychotic disorders were recruited from community mental health services. Cluster randomisation was used to allocate health professionals (care co-ordinators) and their associated patients to use of the Medication Review Tool or usual care. All participants had a medical consultation scheduled, and those in the intervention group completed the Medication Review Tool, with the help of their health professional prior to this, and took the completed Form into the consultation. Two follow-up interviews were conducted up to three months after the consultation. The principal outcome was the Decision Self Efficacy Scale (DSES). Qualitative feedback was collected from patients in the intervention group. RESULTS: One hundred and thirty patients were screened, sixty patients were randomised, 51 completed the first follow-up assessment and 49 completed the second. Many patients were not randomised due to the timing of their consultation, and involvement of health professionals was inconsistent. There was no difference between the groups on the DSES (-4.16 95Â % CI -9.81, 1.49), symptoms, side effects, antipsychotic doses or patient satisfaction. Scores on the Medication Adherence Questionnaire indicated an increase in participants' reported inclination to adherence in the intervention group (coefficient adjusted for baseline values -0.44; 95Â % CI -0.76, -0.11), and there was a small increase in positive attitudes to antipsychotic medication (Drug Attitude Inventory, adjusted coefficient 1.65; 95Â % CI -0.09, 3.40). Qualitative feedback indicated patients valued the Tool for identifying both positive and negative aspects of drug treatment. CONCLUSIONS: The trial demonstrated the design was feasible, although challenges included service re-configurations and maintaining health professional involvement. Results may indicate a more intensive and sustained intervention is required to facilitate participation in decision-making for this group of patients. TRIAL REGISTRATION: Current controlled trials ISRCTN12055530 , Retrospectively registered 9/12/2013
Five New Millisecond Pulsars From a Radio Survey of 14 Unidentified Fermi-LAT Gamma-ray Sources
We have discovered five millisecond pulsars (MSPs) in a survey of 14
unidentified Fermi-LAT sources in the southern sky using the Parkes radio
telescope. PSRs J0101-6422, J1514-4946, and J1902-5105 reside in binaries,
while PSRs J1658-5324 and J1747-4036 are isolated. Using an ephemeris derived
from timing observations of PSR J0101-6422 (P =2.57 ms, DM=12 pc cm-3), we have
detected {\gamma}-ray pulsations and measured its proper motion. Its
{\gamma}-ray spectrum (a power law of {\Gamma} = 0.9 with a cutoff at 1.6 GeV)
and efficiency are typical of other MSPs, but its radio and {\gamma}-ray light
curves challenge simple geometric models of emission. The high success rate of
this survey-enabled by selecting {\gamma}-ray sources based on their detailed
spectral characteristics-and other similarly successful searches indicate that
a substantial fraction of the local population of MSPs may soon be known.Comment: 6 pages, 3 figures, 2 tables, accepted by ApJ
A Ball in a Groove
We study the static equilibrium of an elastic sphere held in a rigid groove
by gravity and frictional contacts, as determined by contact mechanics. As a
function of the opening angle of the groove and the tilt of the groove with
respect to the vertical, we identify two regimes of static equilibrium for the
ball. In the first of these, at large opening angle or low tilt, the ball rolls
at both contacts as it is loaded. This is an analog of the "elastic" regime in
the mechanics of granular media. At smaller opening angles or larger tilts, the
ball rolls at one contact and slides at the other as it is loaded, analogously
with the "plastic" regime in the mechanics of granular media. In the elastic
regime, the stress indeterminacy is resolved by the underlying kinetics of the
ball response to loading.Comment: RevTeX 3.0, 4 pages, 2 eps figures included with eps
An optical surface resonance may render photonic crystals ineffective
In this work we identify and study the presence of extremely intense surface
resonances that frustrate the coupling of photons into a photonic crystal over
crucial energy ranges. The practical utility of photonic crystals demands the
capability to exchange photons with the external medium, therefore, it is
essential to understand the cause of these surface resonances and a route to
their elimination. We demonstrate that by modifying the surface geometry it is
possible to tune the optical response or eliminate the resonances to enable
full exploitation of the photonic crystal.Comment: 6 pages, 8 figures, submitted to PR
Hand Preference Develops Across Childhood and Adolescence in Extremely Preterm Children: The EPICure Study.
AIM: To determine how handedness changes with age and its relation to brain injury and cognition following birth before 26Â weeks of gestation. METHODS: We used data from the EPICure study of health and development following birth in the British Isles in 1995. Handedness was determined by direct observation during standardized testing at age 2.5, six, and 11Â years and by self-report using the Edinburgh Handedness Inventory at 19Â years. Control data from term births were included at six, 11, and 19Â years. RESULTS: In extremely preterm children left handedness increased from 9% to 27% between 2.5 and 19 years, with a progressive reduction in mixed handedness from 59% to 13%. Although individual handedness scores varied over childhood, the between-group effects were consistent through 19Â years, with greatest differences in females. In extremely preterm participants, neonatal brain injury was associated with lower right handedness scores at each age and left-handed participants had lower cognitive scores at 19Â years after controlling for confounders, but not at other ages. CONCLUSION: Increasing hand lateralization is seen over childhood in extremely preterm survivors, but consistently more have non-right preferences at each age than controls
Quality of life in Type 1 (insulin-dependent) diabetic patients prior to and after pancreas and kidney transplantation in relation to organ function
Improvement of the quality of life in Type 1 (insulin-dependent) diabetic patients with severe late complications is one of the main goals of pancreas and/or kidney grafting. To assess the influences of these treatment modalities on the different aspects of the quality of life a cross-sectional study in 157 patients was conducted. They were categorized into patients pre-transplant without dialysis (n=29; Group A), pre-transplant under dialysis (n=44; Group B), post-transplant with pancreas and kidney functioning (n=31; Group C), post-transplant with functioning kidney, but insulin therapy (n=29; Group D), post-transplant under dialysis and insulin therapy again (n=15; Group E) and patients after single pancreas transplantation and rejection, with good renal function, but insulin therapy (n=9; Group F). All patients answered a mailed, self-administered questionnaire (217 questions) consisting of a broad spectrum of rehabilitation criteria. The results indicate a better quality of life in Groups C and D as compared to the other groups. In general the scores are highest in C, but without any significant difference to D. Impressive significant differences between C or D and the other groups were found especially in their satisfaction with physical capacity, leisure-time activities or the overall quality of life. The satisfaction with the latter is highest in C (mean±SEM: 4.0±0.2 on a 1 to 5-rating scale; significantly different from A: 3.1±0.1, B: 2.7±0.2 and E: 2.6±0.3; p<0.01), followed by D (3.8±0.2; significantly different from B and E; p<0.01). Group F shows a mean of 3.1±0.4, which is not significantly different from C. The percentages of patients in each group, who are not working: A: 38 %, B: 64 %, C: 74 %, D: 66 %, E: 87 % and F: 78 % indicate that there is no marked improvement in the vocational situation after successful grafting
Photometric Calibration of the Supernova Legacy Survey Fields
We present the photometric calibration of the Supernova Legacy Survey (SNLS)
fields. The SNLS aims at measuring the distances to SNe Ia at (0.3<z<1) using
MegaCam, the 1 deg^2 imager on the Canada-France-Hawaii Telescope (CFHT). The
uncertainty affecting the photometric calibration of the survey dominates the
systematic uncertainty of the key measurement of the survey, namely the dark
energy equation of state. The photometric calibration of the SNLS requires
obtaining a uniform response across the imager, calibrating the science field
stars in each survey band (SDSS-like ugriz bands) with respect to standards
with known flux in the same bands, and binding the calibration to the UBVRI
Landolt standards used to calibrate the nearby SNe from the literature
necessary to produce cosmological constraints. The spatial non-uniformities of
the imager photometric response are mapped using dithered observations of dense
stellar fields. Photometric zero-points against Landolt standards are obtained.
The linearity of the instrument is studied. We show that the imager filters and
photometric response are not uniform and publish correction maps. We present
models of the effective passbands of the instrument as a function of the
position on the focal plane. We define a natural magnitude system for MegaCam.
We show that the systematics affecting the magnitude-to-flux relations can be
reduced if we use the spectrophotometric standard star BD +17 4708 instead of
Vega as a fundamental flux standard. We publish ugriz catalogs of tertiary
standards for all the SNLS fields.Comment: 46 pages, 23 figures. Accepted by Astronomy and Astrophysics. Online
material available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr
(130.79.128.5) or http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ or
alternatively from: http://supernovae.in2p3.fr/snls3/regnault09_cds.tar.g
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