67 research outputs found

    The Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry

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    The Hubble Deep Field (HDF) is a Director's Discretionary program on HST in Cycle 5 to image an undistinguished field at high Galactic latitude in four passbands as deeply as reasonably possible. These images provide the most detailed view to date of distant field galaxies and are likely to be important for a wide range of studies in galaxy evolution and cosmology. In order to optimize observing in the time available, a field in the northern continuous viewing zone was selected and images were taken for ten consecutive days, or approximately 150 orbits. Shorter 1-2 orbit images were obtained of the fields immediately adjacent to the primary HDF in order to facilitate spectroscopic follow-up by ground-based telescopes. The observations were made from 18 to 30 December 1995, and both raw and reduced data have been put in the public domain as a community service. We present a summary of the criteria for selecting the field, the rationale behind the filter selection and observing times in each band, and the strategies for planning the observations to maximize the exposure time while avoiding earth-scattered light. Data reduction procedures are outlined, and images of the combined frames in each band are presented. Objects detected in these images are listed in a catalog with their basic photometric parameters.Comment: 37 pages, XX PostScript figures, uses aaspp4.sty astrobib.sty. (Astrobib is available from http://www.stsci.edu/software/TeX.html .) To appear the Astronomical Journal. More info on the Hubble deep field can be found at http://www.stsci.edu/../ftp/observer/hdf/hdf.html . More figures (images) can be found at http://www.stsci.edu/../ftp/observer/hdf/references/williams/ and the full source catalog is available at http://www.stsci.edu/../ftp/observer/hdf/archive/v2catalog

    Antenatal weight management: diet, physical activity, and gestational weight gain in early pregnancy

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    Objective: to investigate women’s physical activity levels, diet and gestational weight gain, and their experiences and motivations of behavior change. Design: analysis of cross-sectional data collected during a longitudinal, cohort study examining physiological, psychological, sociodemographic, and self-reported behavioural measures relating to bodyweight. Setting: women recruited from routine antenatal clinics at the Nottingham University Hospitals NHS Trust. Participants: 193 women ≤27 weeks gestation and aged 18 years or over. Measurements & findings: measurements included weight and height, the Dietary Instrument for Nutrition Education (Brief Version), the International Physical Activity Questionnaire (Short Form), and open questions of perceptions of behaviour change. 50.3% (n=97) were overweight/obese, and women gained 0.26kg/wk (IQR 0.34 kg/wk) since conception. The majority consumed low levels of fat (n=121; 63.4%), high levels of unsaturated fat (n=103; 53.9%), and used a dietary supplement (n=166; 86.5%). However, 41% (n=76) were inactive, 74.8% (n=143) did not consume high levels of fibre, and 90.0% (n=171) consumed less than 5 portions of fruit and vegetables a day. Body mass index category was not associated with diet, physical activity levels, or gestational weight gain. Themes generated from open-questions relating to behaviour change were: (1) Risk management, (2) Coping with symptoms, (3) Self-control, (4) Deviation from norm, (5) Nature knows best. Conclusions: early pregnancy is a period of significant and heterogeneous behaviour change, influenced by perceptions of risk and women’s lived experience. Behaviour was influenced not only by perceptions of immediate risk to the fetus, but also by the women’s lived experience of being pregnant. Implications for practice: There are exciting opportunities to constructively reframe health promotion advice relating to physical activity and diet in light of women’s priorities. The need for individualized advice is highlighted, and women across all body mass index categories would benefit from improved diet and physical activity levels

    Antenatal weight management: diet, physical activity, and gestational weight gain in early pregnancy

    Get PDF
    Objective to investigate women's physical activity levels, diet and gestational weight gain, and their experiences and motivations of behavior change. Design analysis of cross-sectional data collected during a longitudinal, cohort study examining physiological, psychological, sociodemographic, and self-reported behavioural measures relating to bodyweight. Setting women recruited from routine antenatal clinics at the Nottingham University Hospitals NHS Trust. Participants 193 women ≤27 weeks gestation and aged 18 years or over. Measurements & findings measurements included weight and height, the Dietary Instrument for Nutrition Education (Brief Version), the International Physical Activity Questionnaire (Short Form), and open questions of perceptions of behaviour change. 50.3% (n=97) were overweight/obese, and women gained 0.26 kg/wk (IQR 0.34 kg/wk) since conception. The majority consumed low levels of fat (n=121; 63.4%), high levels of unsaturated fat (n=103; 53.9%), and used a dietary supplement (n=166; 86.5%). However, 41% (n=76) were inactive, 74.8% (n=143) did not consume high levels of fibre, and 90.0% (n=171) consumed less than 5 portions of fruit and vegetables a day. Body mass index category was not associated with diet, physical activity levels, or gestational weight gain. Themes generated from open-questions relating to behaviour change were: (1) Risk management, (2) Coping with symptoms, (3) Self-control, (4) Deviation from norm, (5) Nature knows best. Conclusions early pregnancy is a period of significant and heterogeneous behaviour change, influenced by perceptions of risk and women's lived experience. Behaviour was influenced not only by perceptions of immediate risk to the fetus, but also by the women's lived experience of being pregnant. Implications for practice: There are exciting opportunities to constructively reframe health promotion advice relating to physical activity and diet in light of women's priorities. The need for individualized advice is highlighted, and women across all body mass index categories would benefit from improved diet and physical activity levels

    ISSN exercise & sport nutrition review: research & recommendations

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    Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients

    Biodegradable Dextran Nanogels for RNA Interference: Focusing on Endosomal Escape and Intracellular siRNA Delivery

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    The successful therapeutic application of small interfering RNA (siRNA) largely relies on the development of safe and effective delivery systems that are able to guide the siRNA therapeutics to the cytoplasm of the target cell. In this report, biodegradable cationic dextran nanogels are engineered by inverse emulsion photopolymerization and their potential as siRNA carriers is evaluated. The nanogels are able to entrap siRNA with a high loading capacity, based on electrostatic interaction. Confocal microscopy and flow cytometry analysis reveal that large amounts of siRNA-loaded nanogels can be internalized by HuH-7 human hepatoma cells without significant cytotoxicity. Following their cellular uptake, it is found that the nanogels are mainly trafficked towards the endolysosomes. The influence of two different strategies to enhance endosomal escape on the extent of gene silencing is investigated. It is found that both the application of photochemical internalization (PCI) and the use of an influenza-derived fusogenic peptide (diINF-7) can significantly improve the silencing efficiency of siRNA-loaded nanogels. Furthermore, it is shown that an efficient gene silencing requires the degradation of the nanogels. As the degradation kinetics of the nanogels can easily be tailored, these particles show potential for intracellular controlled release of short interfering RN
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