602 research outputs found

    Infrared spectroscopy of cataclysmic variables: III. Dwarf novae below the period gap and novalike variables

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    We present K-band spectra of the short-period dwarf novae YZ Cnc, LY Hya, BK Lyn, T Leo, SW UMa and WZ Sge, the novalike variables DW UMa, V1315 Aql, RW Tri, VY Scl, UU Aqr and GP Com, and a series of field dwarf stars with spectral types ranging from K2-M6. The spectra of the dwarf novae are dominated by emission lines of HI and HeI. The large velocity and equivalent widths of these lines, in conjunction with the fact that the lines are double-peaked in the highest inclination systems, indicate an accretion disc origin. In the case of YZ Cnc and T Leo, for which we obtained time-resolved data covering a complete orbital cycle, the emission lines show modulations in their equivalent widths which are most probably associated with the bright spot (the region where the gas stream collides with the accretion disc). There are no clear detections of the secondary star in any of the dwarf novae below the period gap, yielding upper limits of 10-30% for the contribution of the secondary star to the observed K-band flux. In conjunction with the K-band magnitudes of the dwarf novae, we use the derived secondary star contributions to calculate lower limits to the distances to these systems. The spectra of the novalike variables are dominated by broad, single-peaked emission lines of HI and HeI - even the eclipsing systems we observed do not show the double-peaked profiles predicted by standard accretion disc theory. With the exception of RW Tri, which exhibits NaI, CaI and 12CO absorption features consistent with a M0V secondary contributing 65% of the observed K-band flux, we find no evidence for the secondary star in any of the novalike variables. The implications of this result are discussed.Comment: 13 pages, 5 figures, to appear in MNRA

    The Quiescent Spectrum of the AM CVn star CP Eri

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    We used the 6.5m MMT to obtain a spectrum of the AM CVn star CP Eri in quiescence. The spectrum is dominated by He I emission lines, which are clearly double peaked with a peak-to-peak separation of ~1900 km/s. The spectrum is similar to that of the longer period AM CVn systems GP Com and CE 315, linking the short and the long period AM CVn systems. In contrast with GP Com and CE 315, the spectrum of CP Eri does not show a central 'spike' in the line profiles, but it does show lines of SiII in emission. The presence of these lines indicates that the material being transferred is of higher metallicity than in GP Com and CE 315, which, combined with the low proper motion of the system, probably excludes a halo origin of the progenitor of CP Eri. We constrain the primary mass to M_1>0.27 M_sun and the orbital inclination to 33 degr < i < 80 degr. The presence of the He I lines in emission opens up the possibility for phase resolved spectroscopic studies which allows a determination of the system parameters and a detailed study of helium accretion disks under highly varying circumstances.Comment: 12 pages, 2 figures, accepted for publication in ApJ Letter

    Managing, making sense of and finding meaning in advanced illness: a qualitative exploration of the coping and wellbeing experiences of patients with lung cancer

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    Coping plays an essential role in maintaining the wellbeing of patients with cancer. A number of different coping responses and strategies have been identified in the literature. The value and relevance of meaning based coping theory has also been emphasised, including Antonovosky’s (1979) Sense of Coherence (SoC) theory. Ten patients with advanced lung cancer were interviewed up to three times. A total of twenty in depth interviews were carried out, fully transcribed and data were analysed following a methodology of Interpretative Phenomenological Analysis. Three broad domains were identified to categorise the core life concerns of participants; making sense of and managing one’s illness; maintaining daily life and relationships and confronting the future. Within these domains multiple coping themes are identified, which to varying degrees help to maintain patient wellbeing and quality of life. This paper considers the relevance of SoC theory for understanding the coping experiences of patients with advanced cancer, and identifies resources and factors likely to support patient coping, with implications for health and social care services

    The role of Allied Health Professions and Nursing Research Internships in developing a research culture: a mixed-methods exploration of stakeholder perspectives

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    Background: Developing research capability and capacity within the healthcare professions is a challenge throughout diverse international settings. Within England, the National Institute for Health Research aimed to address these challenges through the Integrated Clinical Academic (ICA) research careers escalator for nurses, midwives and allied health professionals. Poor academic progression has been identified in the advanced stages of the pathway, though progression from the earlier entry point (Internship) has not previously been investigated. A national evaluation of four completed Internship cohorts was undertaken to explore stakeholder perspectives and progression beyond the Internship programme. Methods A mixed methods project used sequential qualitative and quantitative data collection phases commencing with two stakeholder focus groups (n = 10); the findings informed the development of an online survey distributed to previous cohorts of interns (n = 104), their managers (n = 12) and academic mentors (n = 36). Eight semi-structured interviews subsequently explored the challenges and opportunities afforded by the internships. Thematic analysis was used to review qualitative data from focus groups and interviews, with survey data analysed and displayed using descriptive statistics. Synthesis of data from each phase is displayed within the four level evaluation framework outlined within the New World Kirkpatrick® Training Evaluation Model. Results Important regional differences exist yet the internships are highly valued by all stakeholders. Representation varied between different professions, with nursing and some service-based professions poorly represented. All interns successfully completed the programme (n = 104), with evidence of positive impacts on interns, colleagues and patient care. Balancing research commitments with clinical activity was challenging; middle managers were seen as gatekeepers to programme success. Progression to the next stage of the ICA pathway is highly competitive and was achieved by only a quarter of interns; access to mentors outside of the funded programme is vital for a successful transition. Conclusions The Internship programme succeeds in providing a range of important early experiences in research, though progression beyond the programme is challenging due, in part, to a widening gap between Internship and the next level of the ICA framework. Vital mentorship support to bridge this gap is threatened by a lack of time and funding; therefore, the pursuit of a clinical-academic career will continue to be elusive for many nurses and allied health professionals. A partnership approach to clinical academic support at institutional level is needed with several international models offering alternative strategies for consideration

    The LMC supersoft X-ray binary RX J0513.9-6951

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    A detailed analysis of simultaneous photometric and spectroscopic observations of the optical counterpart of the LMC "supersoft" X-ray source RX J0513.9-6951 (identified with HV 5682) is presented. The spectrum is dominated by He II emission lines and H + He II blends; no He I is observed but several higher ionization emission features, especially O VI (3811, 3834, and 5290A) are prominent. Radial velocity measurements suggest a binary period of 0.76 days. If the small velocity amplitude, K~11 km/s, is interpreted as orbital motion, this implies that the binary system contains a somewhat evolved star plus a relatively massive compact object, viewed nearly pole-on. No orbital photometric variations were found, although irregular brightness changes of ~0.3 mag occurred. Unusual emission lines are observed which cannot be identified except as high velocity (4000 km/s) bipolar outflows or jets. These outflows are seen in H and He II at the same positive and negative velocities. They were relatively stable for periods of ~5 days, but their velocities appear to have been ~250 km/s smaller in 1992 than in 1993 or 1994
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