100 research outputs found

    HD 24355 observed by the Kepler K2 mission: a rapidly oscillating Ap star pulsating in a distorted quadrupole mode

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    We present an analysis of the first Kepler K2 mission observations of a rapidly oscillating Ap (roAp) star, HD 24355 (V = 9.65). The star was discovered in SuperWASP broad-band photometry with a frequency of 224.31 d−1 (2596.18 μHz; P = 6.4 min) and an amplitude of 1.51 mmag, with later spectroscopic analysis of low-resolution spectra showing HD 24355 to be an A5 Vp SrEu star. The high-precision K2 data allow us to identify 13 rotationally split sidelobes to the main pulsation frequency of HD 24355. This number of sidelobes combined with an unusual rotational phase variation show this star to be the most distorted quadrupole roAp pulsator yet observed. In modelling this star, we are able to reproduce well the amplitude modulation of the pulsation, and find a close match to the unusual phase variations. We show this star to have a pulsation frequency higher than the critical cut-off frequency. This is currently the only roAp star observed with the Kepler spacecraft in short cadence mode that has a photometric amplitude detectable from the ground, thus allowing comparison between the mmag amplitude ground-based targets and the μmag spaced-based discoveries. No further pulsation modes are identified in the K2 data, showing this star to be a single-mode pulsator

    Suppressed phase variations in a high amplitude rapidly oscillating Ap star pulsating in a distorted quadrupole mode

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    We present the results of a multisite photometric observing campaign on the rapidly oscillating Ap (roAp) star 2MASS 16400299-0737293 (J1640; V=12.7V=12.7). We analyse photometric BB data to show the star pulsates at a frequency of 151.93151.93 d−1^{-1} (1758.45μ1758.45 \muHz; P=9.5P=9.5 min) with a peak-to-peak amplitude of 20.68 mmag, making it one of the highest amplitude roAp stars. No further pulsation modes are detected. The stellar rotation period is measured at 3.6747±0.00053.6747\pm0.0005 d, and we show that rotational modulation due to spots is in anti-phase between broadband and BB observations. Analysis and modelling of the pulsation reveals this star to be pulsating in a distorted quadrupole mode, but with a strong spherically symmetric component. The pulsational phase variation in this star is suppressed, leading to the conclusion that the contribution of ℓ>2\ell>2 components dictate the shape of phase variations in roAp stars that pulsate in quadrupole modes. This is only the fourth time such a strong pulsation phase suppression has been observed, leading us to question the mechanisms at work in these stars. We classify J1640 as an A7 Vp SrEu(Cr) star through analysis of classification resolution spectra

    Nova light curves from the Solar Mass Ejection Imager (SMEI) - II. The extended catalog

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    We present the results from observing nine Galactic novae in eruption with the Solar Mass Ejection Imager (SMEI) between 2004 and 2009. While many of these novae reached peak magnitudes that were either at or approaching the detection limits of SMEI, we were still able to produce light curves that in many cases contained more data at and around the initial rise, peak, and decline than those found in other variable star catalogs. For each nova, we obtained a peak time, maximum magnitude, and for several an estimate of the decline time (t2). Interestingly, although of lower quality than those found in Hounsell et al. (2010a), two of the light curves may indicate the presence of a pre-maximum halt. In addition the high cadence of the SMEI instrument has allowed the detection of low amplitude variations in at least one of the nova light curves

    <em>TESS</em> Cycle 2 observations of roAp stars with 2-min cadence data

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    \ua9 The Author(s) 2023.We present the results of a systematic search of the Transiting Exoplanet Survey Satellite (TESS) 2-min cadence data for new rapidly oscillating Ap (roAp) stars observed during the Cycle 2 phase of its mission. We find seven new roAp stars previously unreported as such and present the analysis of a further 25 roAp stars that are already known. Three of the new stars show multiperiodic pulsations, while all new members are rotationally variable stars, leading to almost 70 per cent (22) of the roAp stars presented being α2 CVn-type variable stars. We show that targeted observations of known chemically peculiar stars are likely to overlook many new roAp stars, and demonstrate that multiepoch observations are necessary to see pulsational behaviour changes. We find a lack of roAp stars close to the blue edge of the theoretical roAp instability strip, and reaffirm that mode instability is observed more frequently with precise, space-based observations. In addition to the Cycle 2 observations, we analyse TESS data for all-known roAp stars. This amounts to 18 further roAp stars observed by TESS. Finally, we list six known roAp stars that TESS is yet to observe. We deduce that the incidence of roAp stars amongst the Ap star population is just 5.5 per cent, raising fundamental questions about the conditions required to excite pulsations in Ap stars. This work, coupled with our previous work on roAp stars in Cycle 1 observations, presents the most comprehensive, homogeneous study of the roAp stars in the TESS nominal mission, with a collection of 112 confirmed roAp stars in total

    Self-Guided Psychological Treatment for Depressive Symptoms: A Meta-Analysis

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    Background: A number of trials have examined the effects of self-guided psychological intervention, without any contact between the participants and a therapist or coach. The results and sizes of these trials have been mixed. This is the first quantitative meta-analysis, aimed at organizing and evaluating the literature, and estimating effect size. Method: We conducted systematic literature searches in PubMed, PsycINFO and Embase up to January 2010, and identified additional studies through earlier meta-analyses, and the references of included studies. We identified seven randomized controlled trials that met our inclusion criteria, with a total of 1,362 respondents. The overall quality of the studies was high. A post-hoc power calculation showed that the studies had sufficient statistical power to detect an effect size of d = 0.19. Results: The overall mean effect size indicating the difference between self-guided psychological treatment and control groups at post-test was d = 0.28 (pless than0.001), which corresponds to a NNT of 6.41. At 4 to 12 months follow-up the effect size was d = 0.23. There was no indication for significant publication bias. Conclusions: We found evidence that self-guided psychological treatment has a small but significant effect on participants with increased levels of depressive symptomatology.Original Publication:Pim Cuijpers, Tara Donker, Robert Johansson, David C. Mohr, Annemieke van Straten and Gerhard Andersson, Self-Guided Psychological Treatment for Depressive Symptoms: A Meta-Analysis, 2011, PLoS ONE, (6), 6.http://dx.doi.org/10.1371/journal.pone.0021274Copyright: Public Library of Science (PLoS)http://www.plos.org

    Genome-Wide Analysis of the Complex Transcriptional Networks of Rice Developing Seeds

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    <div><h3>Background</h3><p>The development of rice (<em>Oryza sativa</em>) seed is closely associated with assimilates storage and plant yield, and is fine controlled by complex regulatory networks. Exhaustive transcriptome analysis of developing rice embryo and endosperm will help to characterize the genes possibly involved in the regulation of seed development and provide clues of yield and quality improvement.</p> <h3>Principal Findings</h3><p>Our analysis showed that genes involved in metabolism regulation, hormone response and cellular organization processes are predominantly expressed during rice development. Interestingly, 191 transcription factor (TF)-encoding genes are predominantly expressed in seed and 59 TFs are regulated during seed development, some of which are homologs of seed-specific TFs or regulators of <em>Arabidopsis</em> seed development. Gene co-expression network analysis showed these TFs associated with multiple cellular and metabolism pathways, indicating a complex regulation of rice seed development. Further, by employing a cold-resistant <em>cultivar</em> Hanfeng (HF), genome-wide analyses of seed transcriptome at normal and low temperature reveal that rice seed is sensitive to low temperature at early stage and many genes associated with seed development are down-regulated by low temperature, indicating that the delayed development of rice seed by low temperature is mainly caused by the inhibition of the development-related genes. The transcriptional response of seed and seedling to low temperature is different, and the differential expressions of genes in signaling and metabolism pathways may contribute to the chilling tolerance of HF during seed development.</p> <h3>Conclusions</h3><p>These results provide informative clues and will significantly improve the understanding of rice seed development regulation and the mechanism of cold response in rice seed.</p> </div

    How Can the Operating Environment for Nutrition Research Be Improved in Sub-Saharan Africa? The Views of African Researchers

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    Optimal nutrition is critical for human development and economic growth. Sub-Saharan Africa is facing high levels of food insecurity and only few sub-Saharan African countries are on track to eradicate extreme poverty and hunger by 2015. Effective research capacity is crucial for addressing emerging challenges and designing appropriate mitigation strategies in sub-Saharan Africa. A clear understanding of the operating environment for nutrition research in sub-Saharan Africa is a much needed prerequisite. We collected data on the barriers and requirements for conducting nutrition research in sub-Saharan Africa through semi-structured interviews with 144 participants involved in nutrition research in 35 countries in sub-Saharan Africa. A total of 133 interviews were retained for coding. The main barriers identified for effective nutrition research were the lack of funding due to poor recognition by policymakers of the importance of nutrition research and under-utilisation of research findings for developing policy, as well as an absence of research priority setting from within Africa. Current research topics were perceived to be mainly determined by funding bodies from outside Africa. Nutrition researchers argued for more commitment from policymakers at national level. The low capacity for nutrition research was mainly seen as a consequence of insufficient numbers of nutrition researchers, limited skills and a poor research infrastructure. In conclusion, African nutrition researchers argued how research priorities need to be identified by African stakeholders, accompanied by consensus building to enable creating a problem-driven national research agenda. In addition, it was considered necessary to promote interactions among researchers, and between researchers and policymakers. Multidisciplinary research and international and cross-African collaboration were seen as crucial to build capacity in sub-Saharan nutrition research

    Creating symbolic cultures of consumption: an analysis of the content of sports wagering advertisements in Australia

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    Background: Since 2008, Australia has seen the rapid emergence of marketing for online and mobile sports wagering. Previous research from other areas of public health, such as tobacco and alcohol, has identified the range of appeal strategies these industries used to align their products with culturally valued symbols. However, there is very limited research that has investigated the tactics the sports wagering industry uses within marketing to influence the consumption of its products and services. Method: This study consisted of a mixed method interpretive content analysis of 85 sports wagering advertisements from 11 Australian and multinational wagering companies. Advertisements were identified via internet searches and industry websites. A coding framework was applied to investigate the extent and nature of symbolic appeal strategies within advertisements. Results: Ten major appeal strategies emerged from this analysis. These included sports fan rituals and behaviours; mateship; gender stereotypes; winning; social status; adventure, thrill and risk; happiness; sexualised imagery; power and control; and patriotism. Symbols relating to sports fan rituals and behaviours, and mateship, were the most common strategies used within the advertisements. Discussion/Conclusions: This research suggests that the appeal strategies used by the sports wagering industry are similar to those strategies adopted by other unhealthy commodity industries. With respect to gambling, analysis revealed that strategies are clearly targeted to young male sports fans. Researchers and public health practitioners should seek to better understand the impact of marketing on the normalisation of sports wagering for this audience segment, and implement strategies to prevent gambling harm

    Determinants of recovery from post-COVID-19 dyspnoea: analysis of UK prospective cohorts of hospitalised COVID-19 patients and community-based controls

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    Background The risk factors for recovery from COVID-19 dyspnoea are poorly understood. We investigated determinants of recovery from dyspnoea in adults with COVID-19 and compared these to determinants of recovery from non-COVID-19 dyspnoea. Methods We used data from two prospective cohort studies: PHOSP-COVID (patients hospitalised between March 2020 and April 2021 with COVID-19) and COVIDENCE UK (community cohort studied over the same time period). PHOSP-COVID data were collected during hospitalisation and at 5-month and 1-year follow-up visits. COVIDENCE UK data were obtained through baseline and monthly online questionnaires. Dyspnoea was measured in both cohorts with the Medical Research Council Dyspnoea Scale. We used multivariable logistic regression to identify determinants associated with a reduction in dyspnoea between 5-month and 1-year follow-up. Findings We included 990 PHOSP-COVID and 3309 COVIDENCE UK participants. We observed higher odds of improvement between 5-month and 1-year follow-up among PHOSP-COVID participants who were younger (odds ratio 1.02 per year, 95% CI 1.01–1.03), male (1.54, 1.16–2.04), neither obese nor severely obese (1.82, 1.06–3.13 and 4.19, 2.14–8.19, respectively), had no pre-existing anxiety or depression (1.56, 1.09–2.22) or cardiovascular disease (1.33, 1.00–1.79), and shorter hospital admission (1.01 per day, 1.00–1.02). Similar associations were found in those recovering from non-COVID-19 dyspnoea, excluding age (and length of hospital admission). Interpretation Factors associated with dyspnoea recovery at 1-year post-discharge among patients hospitalised with COVID-19 were similar to those among community controls without COVID-19. Funding PHOSP-COVID is supported by a grant from the MRC-UK Research and Innovation and the Department of Health and Social Care through the National Institute for Health Research (NIHR) rapid response panel to tackle COVID-19. The views expressed in the publication are those of the author(s) and not necessarily those of the National Health Service (NHS), the NIHR or the Department of Health and Social Care. COVIDENCE UK is supported by the UK Research and Innovation, the National Institute for Health Research, and Barts Charity. The views expressed are those of the authors and not necessarily those of the funders
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