4,593 research outputs found

    The Chemical Compositions of the Type II Cepheids -- The BL Her and W Vir Variables

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    Abundance analyses from high-resolution optical spectra are presented for 19 Type II Cepheids in the Galactic field. The sample includes both short-period (BL Her) and long-period (W Vir) stars. This is the first extensive abundance analysis of these variables. The C, N, and O abundances with similar spreads for the BL Her and W Vir show evidence for an atmosphere contaminated with 3α3\alpha-process and CN-cycling products. A notable anomaly of the BL Her stars is an overabundance of Na by a factor of about five relative to their presumed initial abundances. This overabundance is not seen in the W Vir stars. The abundance anomalies running from mild to extreme in W Vir stars but not seen in the BL Her stars are attributed to dust-gas separation that provides an atmosphere deficient in elements of high condensation temperature, notably Al, Ca, Sc, Ti, and ss-process elements. Such anomalies have previously been seen among RV Tau stars which represent a long-period extension of the variability enjoyed by the Type II Cepheids. Comments are offered on how the contrasting abundance anomalies of BL Her and W Vir stars may be explained in terms of the stars' evolution from the blue horizontal branch.Comment: 41 pages including 11 figures and 4 tables; Accepted for publication in Ap

    Twitter Users' Views on Mental Health Crisis Resolution Team Care Compared With Stakeholder Interviews and Focus Groups: Qualitative Analysis

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    BACKGROUND: Analyzing Twitter posts enables rapid access to how issues and experiences are socially shared and constructed among communities of health service users and providers, in ways that traditional qualitative methods may not. OBJECTIVE: To enrich the understanding of mental health crisis care in the United Kingdom, this study explores views on crisis resolution teams (CRTs) expressed on Twitter. We aim to identify the similarities and differences among views expressed on Twitter compared with interviews and focus groups. METHODS: We used Twitter's advanced search function to retrieve public tweets on CRTs. A thematic analysis was conducted on 500 randomly selected tweets. The principles of refutational synthesis were applied to compare themes with those identified in a multicenter qualitative interview study. RESULTS: The most popular hashtag identified was #CrisisTeamFail, where posts were principally related to poor quality of care and access, particularly for people given a personality disorder diagnosis. Posts about CRTs giving unhelpful self-management advice were common, as were tweets about resource strains on mental health services. This was not identified in the research interviews. Although each source yielded unique themes, there were some overlaps with themes identified via interviews and focus groups, including the importance of rapid access to care. Views expressed on Twitter were generally more critical than those obtained via face-to-face methods. CONCLUSIONS: Traditional qualitative studies may underrepresent the views of more critical stakeholders by collecting data from participants accessed via mental health services. Research on social media content can complement traditional or face-to-face methods and ensure that a broad spectrum of viewpoints can inform service development and policy

    Loneliness in early psychosis: a qualitative study exploring the views of mental health practitioners in early intervention services

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    BACKGROUND: Loneliness is an important public health problem with established adverse effects on physical and mental health. Although people with psychosis often experience high levels of loneliness, relatively little is known about the relationship between loneliness and early psychosis. Potential interventions to address loneliness might be easier to implement early in the illness when social networks and social skills may be more intact than at a later stage. We investigated the views of mental health practitioners about the context and causes of loneliness in people with early psychosis, and about potential interventions. METHODS: Semi-structured face-to-face interviews were conducted with mental health practitioners (n = 20). Participants were purposively recruited from four early intervention services for first-episode psychosis in the UK. Interviews were transcribed verbatim and thematic analysis was conducted. RESULTS: Participants believed that the majority of service users with early psychosis experience feelings of loneliness. They often saw socially isolated and disconnected clients and believed them to be lonely, but rarely discussed loneliness explicitly in clinical interactions. A combination of symptoms, stigma and negative sense of self were believed to underpin loneliness. Participants could not identify any specific current interventions delivered by their services for tackling loneliness, but thought some routinely provided interventions, including social groups and psychological treatments, could be helpful. They favoured making a wider range of loneliness interventions available and believed that community agencies beyond mental health services should be involved to make these effective and feasible to deliver. They suggested social participation interventions without an explicit mental health focus as potentially promising and valued a co-produced approach to intervention development. CONCLUSIONS: This study suggests that loneliness is not routinely discussed in early intervention services, and a targeted strategy for tackling it is lacking. Co-produced, individualised community approaches, and interventions that target symptoms, stigma and negative self-schemas might be beneficial in alleviating loneliness for people with early psychosis. Empirical research is needed to develop and test such interventions

    A Sr-Rich Star on the Main Sequence of Omega Centauri

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    Abundance ratios relative to iron for carbon, nitrogen, strontium and barium are presented for a metal-rich main sequence star ([Fe/H]=--0.74) in the globular cluster omega Centauri. This star, designated 2015448, shows depleted carbon and solar nitrogen, but more interestingly, shows an enhanced abundance ratio of strontium [Sr/Fe] ~ 1.6 dex, while the barium abundance ratio is [Ba/Fe]<0.6 dex. At this metallicity one usually sees strontium and barium abundance ratios that are roughly equal. Possible formation scenarios of this peculiar object are considered.Comment: 13 pages, 3 figures. Accepted to ApJ

    Lyapunov instability for a periodic Lorentz gas thermostated by deterministic scattering

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    In recent work a deterministic and time-reversible boundary thermostat called thermostating by deterministic scattering has been introduced for the periodic Lorentz gas [Phys. Rev. Lett. {\bf 84}, 4268 (2000)]. Here we assess the nonlinear properties of this new dynamical system by numerically calculating its Lyapunov exponents. Based on a revised method for computing Lyapunov exponents, which employs periodic orthonormalization with a constraint, we present results for the Lyapunov exponents and related quantities in equilibrium and nonequilibrium. Finally, we check whether we obtain the same relations between quantities characterizing the microscopic chaotic dynamics and quantities characterizing macroscopic transport as obtained for conventional deterministic and time-reversible bulk thermostats.Comment: 18 pages (revtex), 7 figures (postscript

    Fundamental parameters of Cepheids. V. Additional photometry and radial velocity for southern Cepheids

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    I present photometric and radial velocity data for Galactic Cepheids, most of them being in the southern hemisphere. There are 1250 Geneva 7-color photometric measurements for 62 Cepheids, the average uncertainty per measurement is better than 0.01 mag. A total of 832 velocity measurements have been obtained with the CORAVEL radial velocity spectrograph for 46 Cepheids. The average accuracy of the radial velocity data is 0.38 km/s. There are 33 stars with both photometry and radial velocity data. I discuss the possible binarity or period change that these new data reveal. I also present reddenings for all Cepheids with photometry. The data are available electronically.Comment: To appear in ApJS. Data available electronically at ftp://cfa-ftp.harvard.edu/pub/dbersier

    High-resolution spectroscopy of QY Sge -- An obscured RV Tauri variable?

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    The first high-resolution optical spectra of QY Sge are presented and discussed. Menzies & Whitelock (1988) on the basis of photometry and low-resolution spectra suggested that this G0I supergiant was obscured by dust and seen only by scattered light from a circumstellar reflection nebula. The new spectra confirm and extend this picture. Photospheric lines are unusually broad indicating scattering of photons from dust in the stellar wind. Presence of very broad Na D emission lines is confirmed. Sharp emission lines from low levels of abundant neutral metal atoms are reported for the first time. An abundance analysis of photospheric lines shows that the stellar atmosphere is of approximately solar composition but with highly condensible (e.g., Sc and Ti) elements depleted by factors of 5 to 10.Comment: 8 pages, 9 figures, accepted for publication in MNRA

    The Relationship between Therapeutic Alliance and Service User Satisfaction in Mental Health Inpatient Wards and Crisis House Alternatives: A Cross-Sectional Study

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    Background Poor service user experiences are often reported on mental health inpatient wards. Crisis houses are an alternative, but evidence is limited. This paper investigates therapeutic alliances in acute wards and crisis houses, exploring how far stronger therapeutic alliance may underlie greater client satisfaction in crisis houses. Methods and Findings Mixed methods were used. In the quantitative component, 108 crisis house and 247 acute ward service users responded to measures of satisfaction, therapeutic relationships, informal peer support, recovery and negative events experienced during the admission. Linear regressions were conducted to estimate the association between service setting and measures, and to model the factors associated with satisfaction. Qualitative interviews exploring therapeutic alliances were conducted with service users and staff in each setting and analysed thematically. Results We found that therapeutic alliances, service user satisfaction and informal peer support were greater in crisis houses than on acute wards, whilst self-rated recovery and numbers of negative events were lower. Adjusted multivariable analyses suggest that therapeutic relationships, informal peer support and negative experiences related to staff may be important factors in accounting for greater satisfaction in crisis houses. Qualitative results suggest factors that influence therapeutic alliances include service user perceptions of basic human qualities such as kindness and empathy in staff and, at service level, the extent of loss of liberty and autonomy. Conclusions and Implications We found that service users experience better therapeutic relationships and higher satisfaction in crisis houses compared to acute wards, although we cannot exclude the possibility that differences in service user characteristics contribute to this. This finding provides some support for the expansion of crisis house provision. Further research is needed to investigate why acute ward service users experience a lack of compassion and humanity from ward staff and how this could be changed
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