7,703 research outputs found

    The colour-magnitude relations of ClJ1226.9+3332, a massive cluster of galaxies at z=0.89

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    (Abridged) The colour-magnitude relations of one of the most massive, high redshift clusters of galaxies known have been studied. Photometry has been measured in the V, R, I, z, F606W, F814W, J and K bands to a depth of K*+2.5 and spectroscopy confirms 27 K band selected cluster members. The V-K colours are equivalent to a rest-frame colour of ~2700A-J, and provide a very sensitive measure of star-formation activity. HST ACS imaging has been used to morphologically classify the galaxies. The cluster has a low early-type fraction compared to nearby clusters, with only 33% of the cluster members having types E or S0. The early-type member galaxies form a clear red-sequence in all colours. The scatter and slope of the relations show no evolution compared to the equivalent Coma cluster relations, suggesting the stellar populations are already very old. The normalisation of the relations has been compared to models based on synthetic stellar populations, and are most consistent with stellar populations forming at z>3. Some late-type galaxies were found to lie on the red-sequence, suggesting that they have very similar stellar populations to the early-types. These results present a picture of a cluster in which the early-type galaxies are all old, but in which there must be future morphological transformation of galaxies to match the early-type fraction of nearby clusters. In order to preserve the tight colour-magnitude relation of early-types seen in nearby clusters, the late-type galaxies must transform their colours, through the cessation of star-formation, before the morphological transformation occurs. Such evolution is observed in the late-types lying on the colour-magnitude relation.Comment: Accepted for publication in MNRAS. 14 pages, 5 figure

    Anomalous optical absorption in overdoped cuprates near the charge-ordering instability

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    We propose an interpretation for the hump observed in the optical conductivity at or below a few hundreds of cm1^{-1}, in overdoped cuprates like the electron-doped Nd_{2-x}Ce_xCuO_{4-y} at x\gtrsim 0.15 and the hole-doped Bi_2Sr_2CuO_6 and La_{2-x}Sr_xCuO_4. This interpretation is based on the direct excitation of charge collective modes, which become nearly critical in the proximity to a charge-ordering instability. The nearly critical character of these excitations entails a peculiar temperature dependence and a pseudo-scaling form of the lineshapes, which are in agreement with the experimental data.Comment: 5 pages, 3 figure

    Seasonal abundance of small cladocerans in Lake Mangakaware, Waikato, New Zealand

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    The seasonal changes in the dynamics and life histories of the Cladocera in Lake Mangakaware, North Island, New Zealand, were studied over 19 months by sampling at weekly or 2-weekly intervals. Lake Mangakaware is a 13.3 ha polymictic lake with high nutrient status, low Secchi disc transparencies, and an unstable thermal regime. The four planktonic cladoceran species (Bosmina longirostris, B. meridionalis, Ceriodaphnia pulchella, and C. dubia) exhibited disjunct population maxima. Only B. longirostris was perennially present. All species exhibited low fecundities and low lipid content, indicating that food resources were limited and that competitive interactions and resistance to starvation were probably important in determining species success. Increases in body size in cooler seasons were unrelated to clutch size, giving further support for the view that available food was limited. These results are consistent with previous experimental findings that subtle differences in life history can determine seasonal success and the outcome of competition between similar species

    Changes in whole body bone mineral composition in a community-based pilot study designed for Mexican-American women at risk for type II diabetes

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    Changes in whole body bone mineral composition in a community-based pilot study designed for Mexican-American women at risk for type II diabetes David C. Castillo, B.S., Maria G. Placeres, B.S., Arely Perez, M.S., Danielle M. Bravo, B.S., Donovan L. Fogt, Ph.D., Zenong Yin, Ph.D. Mobile Health Laboratory, Department of Health and Kinesiology The University of Texas at San Antonio Classification of First Author (Master’s) Background: Osteoporosis is a serious public health concern in the United States that is expected to increase over the next several years, especially in women. The US Surgeon General’s Report on Bone Health states that individuals can decrease the risk of developing osteoporosis with proper combinations of nutrition and physical activity. Diet and exercise are two important factors that have been shown to prevent or delay the onset of type II diabetes, another national top health concern. Intensive lifestyle interventions, such as The Diabetes Prevention Program have shown that type II diabetes can be delayed or prevented by losing moderate amounts of weight through dietary changes and increased physical activity. It is not clear if a lifestyle intervention can impact bone health. Purpose: This pilot study examined the effects of lifestyle intervention (dietary and physical activity behavior modification) on bone mineral density (BMD) and bone mineral content (BMC). The intervention was a 14-week community-based pilot study, based on The Diabetes Prevention Program, designed to reduce risk for type II diabetes in high-risk Mexican American women. The research questions were: Did the lifestyle intervention affect the outcome measures (BMC and BMD)? Were there differences in BMC and BMD between age groups (low-age ≤45 yrs. vs. high-age \u3e45 yrs.)? Were there differences in BMC and BMD between body weight groups (≤78 kg vs. \u3e78.1 kg)? Methods: The study used a one-group pre- and post-test design. Twenty-five non-diabetic Mexican-American females (average age = 45, SD = 10.9; BMI 25-40) participated in a 14-week lifestyle intervention pilot study. Changes in BMD (g/cm2) and BMC (g) were measured at baseline and 14 weeks after baseline using whole body dual-energy x-ray absorptiometry (DXA). Results: results of paired t-test showed a significant increase in whole body BMC (p\u3c .0001) and a marginally significant increase in whole body BMD (p\u3c .06). Results of Analysis of Covariance revealed no significant difference in BMC between age groups and a marginally significant increase of BMD (p\u3c .07) in younger participants compared to older participants, after controlling pretest measure. There was a significant increase in BMC (p\u3c .01) and a marginally significant increase in BMD (p\u3c .08) in the high-body weight group compared to the low weight group after controlling for pretest measure. Conclusions: A lifestyle intervention that utilized a combination of physical activity and dietary modification showed great promise toward preventing the onset of osteoporosis, especially in heavier Mexican-American women

    'Selling it as a holistic health provision and not just about condoms ?' Sexual health services in school settings: current models and their relationship with sex and relationships education policy and provision

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    In this article we discuss the findings from a recent study of UK policy and practice in relation to sexual health services for young people, based in - or closely linked with - schools. This study formed part of a larger project, completed in 2009, which also included a systematic review of international research. The findings discussed in this paper are based on analyses of interviews with 51 service managers and questionnaire returns from 205 school nurses. Four themes are discussed. First, we found three main service permutations, in a context of very diverse and uneven implementation. Second, we identified factors within the school context that shaped and often constrained service provision; some of these also have implications for sex and relationships education (SRE). Third, we found contrasting approaches to the relationship between SRE input and sexual health provision. Fourth, we identified some specific barriers that need to be addressed in order to develop 'young people friendly' services in the school context. The relative autonomy available to school head teachers and governors can represent an obstacle to service provision - and inter-professional collaboration - in a climate where, in many schools, there is still considerable ambivalence about discussing 'sex' openly. In conclusion, we identify areas worthy of further research and development, in order to address some obstacles to sexual health service and SRE provision in schools

    An evaluation of a multi-component adult weight management on referral intervention in a community setting

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    BACKGROUND: National Institute for Health and Care Excellence (NICE) guidance on adult weight management recommends interventions are multi-component. We aimed to assess the implementation and health benefits of a primary care referral to an adult multi-component weight management intervention in a community setting. The intervention was offered through Primary care in National Health Service (NHS) South Gloucestershire, UK, from Oct 2008 to Nov 2010, in partnership with statutory, community and commercial providers. The scheme offered 12 weeks’ community based concurrent support of dietary (Weight Watchers, WW), physical activity (Exercise on Prescription, EOP) and behavioural change (motivational interviewing) components to obese adults. Funding was available for 600 places. RESULTS: Five hundred and fifty nine participants engaged with the intervention, mean age 48 years, 88 % female. Mean weight loss for all engagers was 3.7 kg (95 % confidence interval 3.4, 4.1). Participants completing the intervention achieved the largest weight reduction (mean loss 5.9 kg; 5.3, 6.6). Achievement of 5 % weight loss was higher in completers (58 %; 50, 65) compared to non-completers (19 %; 12, 26) and people who only participated in one commercial component of the intervention (either WW or EOP; 19 %; 13, 24). CONCLUSION: A multi-component weight management programme may be beneficial for weight loss, but a randomized controlled trial is needed to establish effectiveness and to evaluate cost

    The importance of dietary change for men diagnosed with and at risk of prostate cancer:a multi-centre interview study with men, their partners and health professionals

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    BACKGROUND: The diagnosis of prostate cancer (PC) can provide a trigger for dietary change, and there is evidence that healthier diets may improve quality of life and clinical outcomes. However, men’s views about dietary change in PC survivorship are largely unknown. This multi-centre qualitative interview study explored men’s views about dietary change in PC survivorship, to better understand motivations for, and barriers to, achieving desired changes. The role of radical and active surveillance treatments on dietary change and the influence of men’s partners were examined. Focus groups also evaluated stakeholder opinion, including healthcare professionals, about the provision of dietary advice to PC patients. METHODS: A multi-centre interview study explored views about diet and motivations for, and barriers to, dietary change in men at elevated risk or diagnosed with PC following prostate specific antigen (PSA) testing. 58 men and 11 partners were interviewed. Interviews and focus groups were undertaken with 11 healthcare professionals, 5 patients and 4 partners to evaluate stakeholders’ opinions about the feasibility and acceptability of providing dietary advice to PC patients. Data were analysed using methods of constant comparison and thematic analysis. RESULTS: Over half of diagnosed men reported making dietary changes, primarily to promote general or prostate health or facilitate coping, despite their uncertainty about diet-PC links. Interest in dietary advice was high. Information needs varied depending on treatment received, with men on active surveillance more frequently modifying their diet and regarding this as an adjunct therapy. Men considered their partners integral to implementing changes. Provision of dietary advice to men diagnosed with PC was considered by healthcare professionals and men to be feasible and appropriate in the context of a holistic ‘care package’. CONCLUSIONS: Many men make positive dietary changes after PC diagnosis, which are perceived by men and their partners to bring psychological and general health benefits and could help future dietary intervention trials. Men and their partners desire more and better dietary information that may support PC survivorship, particularly among those embarking on active surveillance/monitoring programmes. There are opportunities for healthcare professionals to support PC patients both clinically and psychologically by the routine integration of healthy eating advice into survivorship care plans

    Dust in Spiral Galaxies: Comparing Emission and Absorption to Constrain Small-Scale and Very Cold Structures

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    The detailed distribution of dust in the disks of spiral galaxies is important to understanding the radiative transfer within disks, and to measuring overall dust masses if significant quantities of dust are either very opaque or very cold. We address this issue by comparing measures of dust absorption, using the galaxy-overlap technique in the optical, with measures of the dust grains' thermal emission from 50-2000 micron using ISOPHOT on board ISO and SCUBA at the JCMT. We examine three spiral galaxies projected partially in front of E/S0 galaxies --- AM1316-241, NGC 5545, and NGC 5091 (for NGC 5091 we have only optical and ISO data). Adopting an empirical exponential model for the dust distribution, we compare column densities and dust masses derived from the absorption and emission techniques. This comparison is sensitive to the amount of dust mass in small, opaque structures, which would not contribute strongly to area-weighted absorption measures, and to very cold dust, which would contribute to optical absorption but provide only a small fraction of the sub-mm emission. In AM1316-241, we find global dust masses of 2-5 x 10^7 M_solar, both techniques agreeing at the 50% level. NGC 5545 has about half this dust mass. The concordance of dust masses is well within the errors expected from our knowledge of the radial distribution of dust, and argues against any dominant part of the dust mass being so cold or opaque. The 50-2000 micron data are well fitted by modified Planck functions with an emissivity law beta=-2, at 21 +/- 2 K. We also present 12 micron ISOCAM observations of these pairs.Comparison of H-alpha and 12 micron images of NGC 5545 indicate that ISOCAM images are reliable tracers of star formation.Comment: 16 pages, 4 tables, 8 figures, in press for October Astronomical Journa

    ESO 381-47, an early-type galaxy with extended HI and a star forming ring

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    ESO 381-47 is an early type galaxy with an extended HI disk. GALEX and very deep optical images reveal a distinct stellar ring far outside the optical body with a diameter of ~30 kpc, which has undergone recent star formation at 1.8 x 10^-4 Msun/yr/kpc^-2, consistent with other new results which detect low level star formation below the traditional Kennicutt relation in the outer parts of spiral galaxies. The morphology of this galaxy resembles the recently identified class of ultraviolet objects called extended ultraviolet disks, or XUV-disks. New HI observations of this galaxy taken at the ATCA and in the CnB array at the VLA show that the cold gas lies in an extended (diameter ~90 kpc) ring around the central S0 galaxy. The HI data cube can be well modeled by a warped ring. The faint ionized gas in the inner parts of the galaxy is kinematically decoupled from the stars and instead appears to exhibit velocities consistent with the rotation of the HI ring at larger radius. The peak of the stellar ring, as seen in the optical and UV, is slightly displaced to the inside relative to the peak of the HI ring. We discuss the manner in which this offset could be caused by the propagation of a radial density wave through an existing stellar disk, perhaps triggered by a galaxy collision at the center of the disk, or possibly due to a spiral density wave set up at early times in a disk too hot to form a stellar bar. Gas accretion and resonance effects due to a bar which has since dissolved are also considered to explain the presence of the star forming ring seen in the GALEX and deep optical data.Comment: 48 pages, 16 figures, 4 tables. Accepted for publication in the Astronomical Journa
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