98 research outputs found

    Evidence against a simple two-component model for the far-infrared emission from galaxies

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    Two of the first Infrared Astronomy Satellite (IRAS) results were that galaxies have a wide range of values for the ratio of 60 micron to 100 micron flux density (0.2 less than or equal to S sub 60/S sub 100 less than or equal to 1.0) and that this ratio is correlated with L sub fir, L sub b, L sub fir being the total far-infrared luminosity and L sub b being the luminosity at visible wavelengths (de Jong et al. 1984; Soifer et al. 1984). From these results arose the following simple model for the far-infrared emission from galaxies (de Jong et al. 1984), which has remained the standard model ever since. In this model, the far-infrared emission comes from two dust components: warm dust (T approx. equals 50 K) intermingled with, and heated by, young massive OB stars in molecular clouds and HII regions, and colder dust (T approx. equals 20 K) associated with the diffuse atomic hydrogen in the interstellar medium and heated by the general interstellar radiation field. As the number of young stars in a galaxy increases, S sub 60/S sub 100 increases, because there is a greater proportion of warm dust, and so does L sub fir/L sub b, because most of the radiation from the young stars is absorbed by the dust, leading to a swifter increase in far-infrared emission than in visible light. Although this model explains the basic IRAS results, it is inelegant. It uses two free parameters to fit two data (the 60 and 100 micron flux densities)-and there are now several observations that contradict it. Despite these major problems with the two-component model, it is not clear what should be put in its place. When considering possible models for the far-infrared emission from galaxies, the observational evidence for our own galaxy must be considered. Researchers suspect that the study by Boulanger and Perault (1988) of the far-infrared properties of the local interstellar medium may be particularly relevant. They showed that molecular clouds are leaky - that most of the light from OB stars in molecular clouds does not heat the dust in the clouds, but instead leaks out. The consequence of this is that that while most of the far-infrared emission from the solar neighborhood is from dust associated with diffuse HI, this dust is mostly heated by young stars

    A comparison of the radial distribution of molecular gas and non-thermal radio continuum in spiral disks

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    The present study includes 65 spiral galaxies selected from the Five College Radio Astronomy Observatory (FCRAO) Extragalactic CO Survey for which the major axis distributions of CO emission and 1.49 GHz radio continuum emission are well determined. The radial distribution of the CO emission has been measured with the FCRAO at positions along the major axis that are spaced by one half power beam width (HPBW) (45 seconds). The radial profile of the 1.49 GHz radio continuum emission was constructed by determining the radio emission at the location of the CO measurements from the 1.49 GHz maps of Condon (1987). Large, greater than a factor of ten, radially decreasing gradients in the star formation efficiency are observed for a small percentage, approx. 10 percent, of the spirals in this sample. The majority of spirals, however, are associated with small gradients in the star formation efficiency that do not systematically increase or decrease with radius. That the star formation efficiency does not systematically decrease with radius tends to argue against a global dynamical mechanism, such as a spiral density wave, for being the dominant mechanism triggering disk star formation for the majority of spirals in this sample. The results tend to support the view that the star formation in spiral disks is dominated by a local process that depends more on the molecular cloud properties than the dynamical structure of a galaxy

    Use of the oral beta blocker bisoprolol to reduce the rate of exacerbation in people with chronic obstructive pulmonary disease (COPD) : a randomised controlled trial. (BICS)

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    Acknowledgments We are grateful for the secretarial and data co-ordination support from Janice Cruden. We would like to acknowledge the principal investigators and staff based in trial recruitment sites across the country, the Clinical Research Networks and staff in the Clinical Trials Pharmacy, and the support of the Trial Steering and Data Monitoring Committees. In particular, we have been grateful for the input to the Trial Steering Committee from two lay representatives, Mr Alister Laird and Mr Dave Bertin. Funding {4b} This project was funded by the National Institute for Health Research, Health Technology Assessment Programme (project number 15/130/20). The cardiac sub-study is funded by British Heart Foundation (BHF) Project Grant no. PG/17/64/33205. This report presents independent research commissioned by the National Institute for Health Research (NIHR). The views and opinions expressed by authors in this publication are those of the authors and do not necessarily reflect those of the NHS, the NIHR, MRC, CCF, NETSCC, the Health Technology Assessment programme or the Department of Health.Peer reviewe

    Southampton PRegnancy Intervention for the Next Generation (SPRING):protocol for a randomised controlled trial

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    BACKGROUND: The nutritional status and health of mothers influence the growth and development of infants during pregnancy and postnatal life. Interventions that focus on improving the nutritional status and lifestyle of mothers have the potential to optimise the development of the fetus as well as improve the health of mothers themselves. Improving the diets of women of childbearing age is likely to require complex interventions that are delivered in a socially and culturally appropriate context. In this study we aim to test the efficacy of two interventions: behaviour change (Healthy Conversation Skills) and vitamin D supplementation, and to explore the efficacy of an intervention that combines both, in improving the diet quality and nutritional status of pregnant women. METHODS/DESIGN: Women attending the maternity hospital in Southampton are recruited at between 8 and 12 weeks gestation. They are randomised to one of four groups following a factorial design: Healthy Conversation Skills support plus vitamin D supplementation (1000 IU cholecalciferol) (n = 150); Healthy Conversation Skills support plus placebo (n = 150); usual care plus vitamin D supplementation (n = 150); usual care plus placebo (n = 150). Questionnaire data include parity, sunlight exposure, diet assessment allowing assessment of diet quality, cigarette and alcohol consumption, well-being, self-efficacy and food involvement. At 19 and 34 weeks maternal anthropometry is assessed and blood samples taken to measure 25(OH) vitamin D. Maternal diet quality and 25(OH) vitamin D are the primary outcomes. Secondary outcomes are women's level of self-efficacy at 34 weeks, pregnancy weight gain, women's self-efficacy and breastfeeding status at one month after birth and neonatal bone mineral content, assessed by DXA within the first 14 days after birth. DISCUSSION: This trial is evaluating two approaches to improving maternal diet: a behaviour change intervention and vitamin D supplementation. The factorial design of this trial has the advantage of enabling each intervention to be tested separately as well as allowing exploration of the synergistic effect of both interventions on women's diets and vitamin D levels. TRIAL REGISTRATION: ISRCTN07227232 . Registered on 13 September 2013

    Comparative analysis of somitogenesis related genes of the hairy/Enhancer of split class in Fugu and zebrafish

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    BACKGROUND: Members of a class of bHLH transcription factors, namely the hairy (h), Enhancer of split (E(spl)) and hairy-related with YRPW motif (hey) (h/E(spl)/hey) genes are involved in vertebrate somitogenesis and some of them show cycling expression. By sequence comparison, identified orthologues of cycling somitogenesis genes from higher vertebrates do not show an appropriate expression pattern in zebrafish. The zebrafish genomic sequence is not available yet but the genome of Fugu rubripes was recently published. To allow comparative analysis, the currently known Her proteins from zebrafish were used to screen the genomic sequence database of Fugu rubripes. RESULTS: 20 h/E(spl)/hey-related genes were identified in Fugu, which is twice the number of corresponding zebrafish genes known so far. A novel class of c-Hairy proteins was identified in the genomes of Fugu and Tetraodon. A screen of the human genome database with the Fugu proteins yielded 10 h/E(spl)/hey-related genes. By analysing the upstream sequences of the c-hairy class genes in zebrafish, Fugu and Tetraodon highly similar sequence stretches were identified that harbour Suppressor of hairless paired binding sites (SPS). This motif was also discovered in the upstream sequences of the her1 gene in the examined fish species. Here, the Su(h) sites are separated by longer intervening sequences. CONCLUSIONS: Our study indicates that not all her homologues in zebrafish have been isolated. Comparison to the human genome suggests a selective duplication of h/E(spl) genes in pufferfish or loss of members of these genes during evolution to the human lineage

    A history of high-power laser research and development in the United Kingdom

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    The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years

    ENIGMA CHEK2gether Project: A Comprehensive Study Identifies Functionally Impaired CHEK2 Germline Missense Variants Associated with Increased Breast Cancer Risk

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    PURPOSE: Germline pathogenic variants in CHEK2 confer moderately elevated breast cancer risk (odds ratio, OR ∼ 2.5), qualifying carriers for enhanced breast cancer screening. Besides pathogenic variants, dozens of missense CHEK2 variants of uncertain significance (VUS) have been identified, hampering the clinical utility of germline genetic testing (GGT). EXPERIMENTAL DESIGN: We collected 460 CHEK2 missense VUS identified by the ENIGMA consortium in 15 countries. Their functional characterization was performed using CHEK2-complementation assays quantifying KAP1 phosphorylation and CHK2 autophosphorylation in human RPE1-CHEK2-knockout cells. Concordant results in both functional assays were used to categorize CHEK2 VUS from 12 ENIGMA case-control datasets, including 73,048 female patients with breast cancer and 88,658 ethnicity-matched controls. RESULTS: A total of 430/460 VUS were successfully analyzed, of which 340 (79.1%) were concordant in both functional assays and categorized as functionally impaired (N = 102), functionally intermediate (N = 12), or functionally wild-type (WT)-like (N = 226). We then examined their association with breast cancer risk in the case-control analysis. The OR and 95% CI (confidence intervals) for carriers of functionally impaired, intermediate, and WT-like variants were 2.83 (95% CI, 2.35-3.41), 1.57 (95% CI, 1.41-1.75), and 1.19 (95% CI, 1.08-1.31), respectively. The meta-analysis of population-specific datasets showed similar results. CONCLUSIONS: We determined the functional consequences for the majority of CHEK2 missense VUS found in patients with breast cancer (3,660/4,436; 82.5%). Carriers of functionally impaired missense variants accounted for 0.5% of patients with breast cancer and were associated with a moderate risk similar to that of truncating CHEK2 variants. In contrast, 2.2% of all patients with breast cancer carried functionally wild-type/intermediate missense variants with no clinically relevant breast cancer risk in heterozygous carriers
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