1,752 research outputs found
The GALFA-HI Compact Cloud Catalog
We present a catalog of 1964 isolated, compact neutral hydrogen clouds from
the Galactic Arecibo L-Band Feed Array Survey Data Release One (GALFA-HI DR1).
The clouds were identified by a custom machine-vision algorithm utilizing
Difference of Gaussian kernels to search for clouds smaller than 20'. The
clouds have velocities typically between |VLSR| = 20-400 km/s, linewidths of
2.5-35 km/s, and column densities ranging from 1 - 35 x 10^18 cm^-2. The
distances to the clouds in this catalog may cover several orders of magnitude,
so the masses may range from less than a Solar mass for clouds within the
Galactic disc, to greater than 10^4 Solar Masses for HVCs at the tip of the
Magellanic Stream. To search for trends, we separate the catalog into five
populations based on position, velocity, and linewidth: high velocity clouds
(HVCs); galaxy candidates; cold low velocity clouds (LVCs); warm, low
positive-velocity clouds in the third Galactic Quadrant; and the remaining warm
LVCs. The observed HVCs are found to be associated with previously-identified
HVC complexes. We do not observe a large population of isolated clouds at high
velocities as some models predict. We see evidence for distinct histories at
low velocities in detecting populations of clouds corotating with the Galactic
disc and a set of clouds that is not corotating.Comment: 34 Pages, 9 Figures, published in ApJ (2012, ApJ, 758, 44), this
version has the corrected fluxes and corresponding flux histogram and masse
Experiences of women with cardiac disease in pregnancy: A systematic review and metasynthesis
© Author(s) (or their employer(s)) 2018. Objective Cardiac disease in pregnancy is a leading cause of maternal death in high-income countries. Evidence-based guidelines to assist in planning and managing the healthcare of affected women is lacking. The objective of this research was to produce the first qualitative metasynthesis of the experiences of pregnant women with existing or acquired cardiac disease to inform improved healthcare services. Method We conducted a systematic search of peerreviewed publications in five databases to investigate the decision-making processes, supportive strategies and healthcare experiences of pregnant women with existing or acquired cardiac disease, or of affected women contemplating pregnancy. Identified publications were screened for duplication and eligibility against selection criteria, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We then undertook a thematic analysis of the data relating to women's experiences extracted from each publication to inform new healthcare practices and communication. Results Eleven studies from six countries were included in our meta-synthesis. Four themes were revealed. Women with congenital and acquired heart disease identified situations where they had either taken charge of decision-making, lacked control or experienced emotional uncertainty when making decisions. Some women were risk aware and determined to take care of themselves in pregnancy while others downplayed the risks. Women with heart disease acknowledged the importance of specific social support measures during pregnancy and after child birth, and reported a spectrum of healthcare experiences. Conclusions There is a lack of integrated and tailored healthcare services and information for women with cardiac disease in pregnancy. The experiences of women synthesised in this research has the potential to inform new evidencebased guidelines to support the decision-making needs of women with cardiac disease in pregnancy. Shared decisionmaking must consider communication across the clinical team. However, coordinated care is challenging due to the different specialists involved and the limited clinical evidence concerning effective approaches to managing such complex care
A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
We determine the parallax and proper motion of the flaring, non-thermal radio
star GMR A, a member of the Orion Nebula Cluster, using Very Long Baseline
Array observations. Based on the parallax, we measure a distance of 389 +24/-21
parsecs to the source. Our measurement places the Orion Nebula Cluster
considerably closer than the canonical distance of 480 +/- 80 parsecs
determined by Genzel et al. (1981). A change of this magnitude in distance
lowers the luminosities of the stars in the cluster by a factor of ~ 1.5. We
briefly discuss two effects of this change--an increase in the age spread of
the pre-main sequence stars and better agreement between the zero-age
main-sequence and the temperatures and luminosities of massive stars.Comment: 10 pages, 4 figures, emulateapj, accepted to Ap
Mapping Hydrogen in the Galaxy, Galactic Halo, and Local Group with ALFA: The GALFA-HI Survey Starting with TOGS
Radio observations of gas in the Milky Way and Local Group are vital for
understanding how galaxies function as systems. The unique sensitivity of
Arecibo's 305m dish, coupled with the 7-beam Arecibo L-Band Feed Array (ALFA),
provides an unparalleled tool for investigating the full range of interstellar
phenomena traced by the HI 21cm line. The GALFA (Galactic ALFA) HI Survey is
mapping the entire Arecibo sky over a velocity range of -700 to +700 km/s with
0.2 km/s velocity channels and an angular resolution of 3.4 arcminutes. We
present highlights from the TOGS (Turn on GALFA Survey) portion of GALFA-HI,
which is covering thousands of square degrees in commensal drift scan
observations with the ALFALFA and AGES extragalactic ALFA surveys. This work is
supported in part by the National Astronomy and Ionosphere Center, operated by
Cornell University under cooperative agreement with the National Science
Foundation.Comment: 3 pages, including 2 figure pages; figure image quality significantly
reduced; for full resolution version, please see
http://www.naic.edu/~gibson/cv/ao08_writeup.pdf ; to be published in AIP
conference proceedings for ``The Evolution of Galaxies through the Neutral
Hydrogen Window'', eds. R. Minchin & E. Momjia
The challenges of urban ageing : making cities age-friendly in Europe
Urban ageing is an emerging domain that deals with the population of older people living in cities. The ageing of society is a positive yet challenging phenomenon, as population ageing and urbanisation are the culmination of successful human development. One could argue whether the city environment is an ideal place for people to grow old and live at an old age compared to rural areas. This viewpoint article explores and describes the challenges that are encountered when making cities age-friendly in Europe. Such challenges include the creation of inclusive neighbourhoods and the implementation of technology for ageing-in-place. Examples from projects in two age-friendly cities in The Netherlands (The Hague) and Poland (Cracow) are shown to illustrate the potential of making cities more tuned to the needs of older people and identify important challenges for the next couple of years. Overall, the global ageing of urban populations calls for more age-friendly approaches to be implemented in our cities. It is a challenge to prepare for these developments in such a way that both current and future generations of older people can benefit from age-friendly strategies
Multiphysics simulation of corona discharge induced ionic wind
Ionic wind devices or electrostatic fluid accelerators are becoming of
increasing interest as tools for thermal management, in particular for
semiconductor devices. In this work, we present a numerical model for
predicting the performance of such devices, whose main benefit is the ability
to accurately predict the amount of charge injected at the corona electrode.
Our multiphysics numerical model consists of a highly nonlinear strongly
coupled set of PDEs including the Navier-Stokes equations for fluid flow,
Poisson's equation for electrostatic potential, charge continuity and heat
transfer equations. To solve this system we employ a staggered solution
algorithm that generalizes Gummel's algorithm for charge transport in
semiconductors. Predictions of our simulations are validated by comparison with
experimental measurements and are shown to closely match. Finally, our
simulation tool is used to estimate the effectiveness of the design of an
electrohydrodynamic cooling apparatus for power electronics applications.Comment: 24 pages, 17 figure
Development and validation of the DIabetes Severity SCOre (DISSCO) in 139 626 individuals with type 2 diabetes: a retrospective cohort study
OBJECTIVE: Clinically applicable diabetes severity measures are lacking, with no previous studies comparing their predictive value with glycated hemoglobin (HbA1c). We developed and validated a type 2 diabetes severity score (the DIabetes Severity SCOre, DISSCO) and evaluated its association with risks of hospitalization and mortality, assessing its additional risk information to sociodemographic factors and HbA1c.
RESEARCH DESIGN AND METHODS: We used UK primary and secondary care data for 139 626 individuals with type 2 diabetes between 2007 and 2017, aged ≥35 years, and registered in general practices in England. The study cohort was randomly divided into a training cohort (n=111 748, 80%) to develop the severity tool and a validation cohort (n=27 878). We developed baseline and longitudinal severity scores using 34 diabetes-related domains. Cox regression models (adjusted for age, gender, ethnicity, deprivation, and HbA1c) were used for primary (all-cause mortality) and secondary (hospitalization due to any cause, diabetes, hypoglycemia, or cardiovascular disease or procedures) outcomes. Likelihood ratio (LR) tests were fitted to assess the significance of adding DISSCO to the sociodemographics and HbA1c models.
RESULTS: A total of 139 626 patients registered in 400 general practices, aged 63±12 years were included, 45% of whom were women, 83% were White, and 18% were from deprived areas. The mean baseline severity score was 1.3±2.0. Overall, 27 362 (20%) people died and 99 951 (72%) had ≥1 hospitalization. In the training cohort, a one-unit increase in baseline DISSCO was associated with higher hazard of mortality (HR: 1.14, 95% CI 1.13 to 1.15, area under the receiver operating characteristics curve (AUROC)=0.76) and cardiovascular hospitalization (HR: 1.45, 95% CI 1.43 to 1.46, AUROC=0.73). The LR tests showed that adding DISSCO to sociodemographic variables significantly improved the predictive value of survival models, outperforming the added value of HbA1c for all outcomes. Findings were consistent in the validation cohort.
CONCLUSIONS: Higher levels of DISSCO are associated with higher risks for hospital admissions and mortality. The new severity score had higher predictive value than the proxy used in clinical practice, HbA1c. This reproducible algorithm can help practitioners stratify clinical care of patients with type 2 diabetes
An Accurate Distance to High-Velocity Cloud Complex C
We report an accurate distance of d = 10+/-2.5kpc to the high-velocity cloud
Complex C. Using high signal-to-noise Keck/HIRES spectra of two
horizontal-branch stars, we have detected CaII K absorption lines from the
cloud. Significant non-detections toward a further 3 stars yield robust lower
distance limits. The resulting HI mass of Complex C is 4.9^{+2.8}_{-2.2} x 10^6
Msun; a total mass of 8.2^{+4.6}_{-2.6} x 10^6 Msun is implied, after
corrections for helium and ionization. At 10kpc, Complex C has physical
dimensions 3x15 kpc, and if it is as thick as it is wide, then the average
density is log ~ -2.5. We estimate the contribution of Complex C to the mass
influx may be as high as ~0.14 Msun/yr.Comment: Resubmitted to ApJ. 8 figure
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