297 research outputs found
Experimental investigation of the performance of various wick configurations in single and two fluid heat pipes operating in the gravitational field
Performance of various wick configurations in single and two-fluid heat pipes operating as thermoregulatory system for space suit
The Luminosity Function of Galaxies in Compact Groups
From R-band images of 39 Hickson compact groups (HCGs), we use galaxy counts
to determine a luminosity function extending to M_R=-14.0, approximately two
magnitudes deeper than previous compact group luminosity functions. We find
that a single Schechter function is a poor fit to the data, so we fit a
composite function consisting of separate Schechter functions for the bright
and faint galaxies. The bright end is best fit with M^*=-21.6 and alpha=-0.52
and the faint end with M^*=-16.1 and alpha=-1.17. The decreasing bright end
slope implies a deficit of intermediate luminosity galaxies in our sample of
HCGs and the faint end slope is slightly steeper than that reported for earlier
HCG luminosity functions. Furthermore, luminosity functions of subsets of our
sample reveal more substantial dwarf populations for groups with x-ray halos,
groups with tidal dwarf candidates, and groups with a dominant elliptical or
lenticular galaxy. Collectively, these results support the hypothesis that
within compact groups, the initial dwarf galaxy population is replenished by
"subsequent generations" formed in the tidal debris of giant galaxy
interactions.Comment: 26 pages, to be published in The Astrophysical Journal, 8 greyscale
plates (figures 1 and 2) can be retrieved at
http://www.astro.psu.edu/users/sdh/pubs.htm
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Physician Care Patterns and Adherence to Postpartum Glucose Testing after Gestational Diabetes Mellitus in Oregon
Objective: This study examines obstetrician/gynecologists and family medicine physicians' reported care patterns, attitudes and beliefs and predictors of adherence to postpartum testing in women with a history of gestational diabetes mellitus.
Research Design and Methods: In November-December 2005, a mailed survey went to a random, cross-sectional sample of 683 Oregon licensed physicians in obstetrician/gynecologists and family medicine from a population of 2171.
Results: Routine postpartum glucose tolerance testing by both family physicians (19.3%) and obstetrician/gynecologists physicians (35.3%) was reportedly low among the 285 respondents (42% response rate). Factors associated with high adherence to postpartum testing included physician stated priority (OR 4.39, 95% CI: 1.69-7.94) and physician beliefs about norms or typical testing practices (OR 3.66, 95% CI: 1.65-11.69). Specialty, sex of physician, years of practice, location, type of practice, other attitudes and beliefs were not associated with postpartum glucose tolerance testing.
Conclusions: Postpartum glucose tolerance testing following a gestational diabetes mellitus pregnancy was not routinely practiced by responders to this survey. Our findings indicate that physician knowledge, attitudes and beliefs may in part explain suboptimal postpartum testing. Although guidelines for postpartum care are established, some physicians do not prioritize these guidelines in practice and do not believe postpartum testing is the norm among their peers
Identifying Old Tidal Dwarf Irregulars
We examine the observational consequences of the two possible origins for
irregular galaxies: formation from collapse of a primordial cloud of gas early
in the age of the Universe, and formation from tidal tails in an interaction
that could have occured any time in the history of the Universe. Because the
formation from tidal tails could have occurred a long time ago, proximity to
larger galaxies is not sufficient to distinguish tidal dwarfs from traditional
dwarfs. We consider the effects of little or no dark matter on rotation speeds
and the Tully-Fisher relationship, the metallicity-luminosity relationship,
structure, and stellar populations. From these selection criteria, we identify
a small list of dwarf irregular galaxies that are candidates for having formed
as tidal dwarfs.Comment: ApJ, to appear September 20, 200
Relationship between perception of emotional home atmosphere and fruit and vegetable consumption in European adolescents: Results from the I.Family survey
Objective: Consumption of fruits and vegetables (F&V) among adolescents falls below recommendations in many Western countries. The impact of social and emotional aspects of family life on adolescent dietary behaviour may contribute to this, yet remains under-investigated. The present study examines the association between adolescents'' perceptions of emotional home atmosphere (EHA) and their F&V consumption frequency.
Design: An FFQ was used to assess F&V consumption frequency. EHA was assessed by an eight-item measure with three subscales: Perceived home warmth, strictness and relational tension. EHA subscales were used as binary variables: A score equal to or above the median value was considered as a higher perception, while a score below the median was considered as a lower perception of the EHA in question. Country differences in meeting the European 5-a-day recommendations were described. Further, the association between EHA and F&V consumption frequency was investigated using multiple linear regression.
Setting: Regional examination centres in eight European countries.
Participants: Adolescents (n 3196) aged 12-18 years.
Results: The mean F&V consumption frequency was 3·27 (sd 2·84) times/d. Only 16·1 % of boys and 18 % of girls in our study sample met the recommendation of five F&V daily. After controlling for age, sex, education level of the parents and country of origin, perceived home warmth was associated with a 16 (95 % CI 9, 22) % higher F&V consumption frequency (P < 0·001).
Conclusions: F&V consumption frequency was suboptimal in the survey areas. Interventions targeting perceived warmth as a component of EHA could potentially have a positive effect on adolescents'' dietary behaviour
High-intensity activity is more strongly associated with metabolic health in children compared to sedentary time: a cross-sectional study of the I.Family cohort
Background: Physical activity (PA) during childhood is important for preventing future metabolic syndrome (MetS). To examine the relationship between PA and MetS in more detail, accurate measures of PA are needed. Previous studies have only utilized a small part of the information available from accelerometer measured PA. This study investigated the association between measured PA and MetS in children with a new method for data processing and analyses that enable more detailed interpretation of PA intensity level. Methods: The association between PA pattern and risk factors related to MetS was investigated in a cross- sectional sample of children (n = 2592, mean age 10.9 years, 49.4% male) participating in the European multicenter I. Family study. The risk factors examined include body mass index, blood pressure, high-density lipoprotein cholesterol, insulin resistance and a combined risk factor score (MetS score). PA was measured by triaxial accelerometers and raw data was processed using the 10 Hz frequency extended method (FEM). The PA output was divided into an intensity spectrum and the association with MetS risk factors was analyzed by partial least squares regression. Results: PA patterns differed between the European countries investigated, with Swedish children being most active and Italian children least active. Moderate intensity physical activity was associated with lower insulin resistance (R2 = 2.8%), while vigorous intensity physical activity was associated with lower body mass index (R2 = 3.6%), MetS score (R2 = 3.1%) and higher high-density lipoprotein cholesterol (R2 = 2.3%). PA of all intensities was associated with lower systolic- and diastolic blood pressure, although the associations were weaker than for the other risk factors (R2 = 1.5% and R2 = 1.4%). However, the multivariate analysis implies that the entire PA pattern must be considered. The main difference in PA was observed between normal weight and overweight children. Conclusions: The present study suggests a greater importance of more PA corresponding to an intensity of at least brisk walking with inclusion of high-intense exercise, rather than a limited time spent sedentary, in the association to metabolic health in children. The methods of data processing and statistical analysis enabled accurate analysis and interpretation of the health benefits of high intensity PA that have not been shown previously. © 2021, The Author(s)
Dwarf galaxies in Hickson Compact Groups
We observed 5 Hickson Compact Groups with the ESO/MPI 2.2m telescope and WFI
to investigate the dwarf galaxy content and distribution in these galaxy
groups. Our deep imaging and careful selection of the candidate galaxies
revealed a rich population of mainly passively evolving dwarf galaxies, which
is spatially much more extended than the originally defined Hickson Compact
groups. The composite luminosity function of the 5 groups shows a bimodal
structure with a very steep rise in the low luminosity regime. The faint end
slope is close to the predictions of CDM theory for the slope of the Dark
Matter halo mass function.Comment: 5 pages, 4 figures, to appear in the proceedings of the ESO
Astrophysics Symposium: "Groups of Galaxies in the Nearby Universe", eds. I.
Saviane, V. Ivanov, J. Borissova, Springer-Verla
Integrating place-specific livelihood and equity outcomes into global assessments of bioenergy deployment
__Abstract__
Integrated assessment models suggest that the large-scale deployment of bioenergy could contribute to
ambitious climate change mitigation efforts. However, such a shift would intensify the global competition
for land, with possible consequences for 1.5 billion smallholder livelihoods that these models do not
consider. Maintaining and enhancing robust livelihoods upon bioenergy deployment is an equally important
sustainability goal that warrants greater attention. The social implications of biofuel production are
complex, varied and place-specific, difficult to model, operationalize and quantify. However, a rapidly
developing body of social science literature is advancing the understanding of these interactions. In this
letter we link human geography research on the interaction between biofuel crops and livelihoods in
developing countries to integrated assessments on biofuels. We review case-study research focused on
first-generation biofuel crops to demonstrate that food, income, land and other assets such as health are key
livelihood dimensions that can be impacted by such crops and we highlight how place-specific and global
dynamics influence both aggregate and distributional outcomes across these livelihood dimensions. We
argue that place-specific production models and land tenure regimes mediate livelihood outcomes, which
are also in turn affected by global and regional markets and their resulting equilibrium dynamics. The
place-specific perspective suggests that distributional consequences are a crucial complement to aggregate
outcomes; this has not been given enough weight in comprehensive assessments to date. By narrowing the
gap between place-specific case studies and global models, our discussion offers a route towards integrating
livelihood and equity considerations into scenarios of future bioenergy deployment, thus contributing to a
key challenge in sustainability sciences
The First Swift Ultra-Violet/Optical Telescope GRB Afterglow Catalog
We present the first Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray
burst (GRB) afterglow catalog. The catalog contains data from over 64,000
independent UVOT image observations of 229 GRBs first detected by Swift, the
High Energy Transient Explorer 2 (HETE2), the INTErnational Gamma-Ray
Astrophysics Laboratory (INTEGRAL), and the Interplanetary Network (IPN). The
catalog covers GRBs occurring during the period from 2005 Jan 17 to 2007 Jun 16
and includes ~86% of the bursts detected by the Swift Burst Alert Telescope
(BAT). The catalog provides detailed burst positional, temporal, and
photometric information extracted from each of the UVOT images. Positions for
bursts detected at the 3-sigma-level are provided with a nominal accuracy,
relative to the USNO-B1 catalog, of ~0.25 arcseconds. Photometry for each burst
is given in three UV bands, three optical bands, and a 'white' or open filter.
Upper limits for magnitudes are reported for sources detected below 3-sigma.
General properties of the burst sample and light curves, including the
filter-dependent temporal slopes, are also provided. The majority of the UVOT
light curves, for bursts detected at the 3-sigma-level, can be fit by a single
power-law, with a median temporal slope (alpha) of 0.96, beginning several
hundred seconds after the burst trigger and ending at ~1x10^5 s. The median
UVOT v-band (~5500 Angstroms) magnitude at 2000 s for a sample of "well"
detected bursts is 18.02. The UVOT flux interpolated to 2000 s after the burst,
shows relatively strong correlations with both the prompt Swift BAT fluence,
and the Swift X-ray flux at 11 hours after the trigger.Comment: 60 pages, 17 figures, 8 tables, accepted for publication by the
Astrophysical Journa
Ultraviolet, Optical, and X-Ray Observations of the Type Ia Supernova 2005am with Swift
We present ultraviolet and optical light curves in six broadband filters and
grism spectra obtained by Swift's Ultraviolet/Optical Telescope for the Type Ia
supernova SN2005am. The data were collected beginning about four days before
the B-band maximum, with excellent coverage of the rapid decline phase and
later observations extending out to 69 days after the peak. The optical and
near UV light curve match well those of SN1992A. The other UV observations
constitute the first set of light curves shorter than 2500 Angstroms and allow
us to compare the light curve evolution in three UV bands. The UV behavior of
this and other low redshift supernovae can be used to constrain theories of
progenitor evolution or to interpret optical light curves of high redshift
supernovae. Using Swift's X-Ray Telescope, we also report the upper limit to
SN2005am's X-ray luminosity to be 1.77 x 10^40 erg s^-1 in the 0.3--10 keV
range from 58,117 s of exposure time.Comment: 15 pages, including 3 figures and 2 tables, submitted to
Astrophysical Journa
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