17 research outputs found

    Polars Changing State: Multiwavelength Long Term Photometry and Spectroscopy of QS Tel, V834 Cen, and BL Hyi

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    Long term optical and near-infrared photometric and blue spectroscopic observations were obtained for QS Tel, V834 Cen, and BL Hyi. The optical light curves of all three polars displayed large magnitude changes during our observations. These same high/low state transitions were also apparent in near-infrared JHK photometry, though with decreased amplitude. The color of the polar with respect to its state was examined and found not to be a good indicator of the instantaneous state. During low to high state transitions, a nearly constant magnitude difference was observed in all three polars. This Δ\Deltam value was found to be consistent with the level expected to occur if accretion onto the white dwarf reached the Eddington luminosity during the high state. The high state Balmer decrement was measured for each star and used to estimate that the temperature of the emission line forming region was ~12,000K with NH_H near 12.8 dex. No relationship between the Balmer emission line strength and the white dwarf magnetic field strength was seen, in contrast to a good correlation between these two parameters observed for UV emission lines.Comment: 9 figures, 4 tables; accepted for publication in PAS

    A Near-Infrared Survey of the Inner Galactic Plane for Wolf-Rayet Stars I. Methods and First Results: 41 New WR Stars

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    The discovery of new Wolf-Rayet (WR) stars in our Galaxy via large-scale narrowband optical surveys has been severely limited by dust extinction. Recent improvements in infrared technology have made narrowband-broadband imaging surveys viable again. We report a new J, K and narrow-band imaging survey of 300 square degrees of the plane of the Galaxy, spanning 150 degrees in Galactic longitude and reaching 1 degree above and below the Galactic plane. The survey has a useful limiting magnitude of K = 15 over most of the observed Galactic plane, and K = 14 within a few degrees of the Galactic center. Thousands of emission line candidates have been detected. In spectrographic follow-ups of 173 WR star candidates we have discovered 41 new WR stars, 15 of type WN and 26 of type WC. Star subtype assignments have been confirmed with K band spectra, and distances approximated using the method of spectroscopic parallax. A few of the new WR stars are amongst the most distant known in our Galaxy. The distribution of these new WR stars is seen to follow that of previously known WR stars along the spiral arms of the Galaxy. Tentative radial velocities were also measured for most of the new WR stars.Comment: 55 pages, 23 figures, 7 tables, accepted to Astronomical Journa

    A Near-Infrared Survey of the Inner Galactic Plane for Wolf-Rayet Stars II. Going Fainter: 71 More New WR Stars

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    We are continuing a J, K and narrow-band imaging survey of 300 square degrees of the plane of the Galaxy, searching for new Wolf-Rayet stars. Our survey spans 150 degrees in Galactic longitude and reaches 1 degree above and below the Galactic plane. The survey has a useful limiting magnitude of K = 15 over most of the observed Galactic plane, and K = 14 (due to severe crowding) within a few degrees of the Galactic center. Thousands of emission line candidates have been detected. In spectrographic follow-ups of 146 relatively bright WR star candidates we have re-examined 11 previously known WC and WN stars and discovered 71 new WR stars, 17 of type WN and 54 of type WC. Our latest image analysis pipeline now picks out WR stars with a 57% success rate. Star subtype assignments have been confirmed with K band spectra, and distances approximated using the method of spectroscopic parallax. Some of the new WR stars are amongst the most distant known in our Galaxy. The distribution of these new WR stars is beginning to trace the locations of massive stars along the distant spiral arms of the Milky Way.Comment: 48 pages, 25 figures, 8 Tables, Accepted by AJ 4-18-201

    “You can’t die here”: an exploration of the barriers to dying-in-place for structurally vulnerable populations in an urban centre in British Columbia, Canada

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    Abstract Background One measure of quality in palliative care involves ensuring people approaching the end of life are able to receive care, and ultimately die, in the places they choose. Canadian palliative care policy directives stem from this tenet of autonomy, acknowledging that most people prefer to die at home, where they feel safe and comfortable. Limited research, however, considers the lack of ‘choice’ people positioned as structurally vulnerable (e.g., experiencing extreme poverty, homelessness, substance-use/criminalization, etc.) have in regard to places of care and death, with the option of dying-in-place most often denied. Methods Drawing from ethnographic and participatory action research data collected during two studies that took place from 2014 to 2019 in an urban centre in British Columbia, Canada, this analysis explores barriers preventing people who experience social and structural inequity the option to die-in-place. Participants include: (1) people positioned as structurally vulnerable on a palliative trajectory; (2) their informal support persons/family caregivers (e.g., street family); (3) community service providers (e.g., housing workers, medical professionals); and (4) key informants (e.g., managers, medical directors, executive directors). Data includes observational fieldnotes, focus group and interviews transcripts. Interpretive thematic analytic techniques were employed. Results Participants on a palliative trajectory lacked access to stable, affordable, or permanent housing, yet expressed their desire to stay ‘in-place’ at the end of life. Analysis reveals three main barriers impeding their ‘choice’ to remain in-place at the end of life: (1) Misaligned perceptions of risk and safety; (2) Challenges managing pain in the context of substance use, stigma, and discrimination; and (3) Gaps between protocols, policies, and procedures for health teams. Conclusions Findings demonstrate how the rhetoric of ‘choice’ in regard to preferred place of death is ethically problematic because experienced inequities are produced and constrained by socio-structural forces that reach beyond individuals’ control. Ultimately, our findings contribute suggestions for policy, programs and practice to enhance inclusiveness in palliative care. Re-defining ‘home’ within palliative care, enhancing supports, education, and training for community care workers, integrating palliative approaches to care into the everyday work of non-health care providers, and acknowledging, valuing, and building upon existing relations of care can help to overcome existing barriers to delivering palliative care in various settings and increase the opportunity for all to spend their end of life in the places that they prefer

    Neuropeptidomic Components Generated by Proteomic Functions in Secretory Vesicles for Cell–Cell Communication

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    Diverse neuropeptides participate in cell–cell communication to coordinate neuronal and endocrine regulation of physiological processes in health and disease. Neuropeptides are short peptides ranging in length from ~3 to 40 amino acid residues that are involved in biological functions of pain, stress, obesity, hypertension, mental disorders, cancer, and numerous health conditions. The unique neuropeptide sequences define their specific biological actions. Significantly, this review article discusses how the neuropeptide field is at the crest of expanding knowledge gained from mass-spectrometry-based neuropeptidomic studies, combined with proteomic analyses for understanding the biosynthesis of neuropeptidomes. The ongoing expansion in neuropeptide diversity lies in the unbiased and global mass-spectrometry-based approaches for identification and quantitation of peptides. Current mass spectrometry technology allows definition of neuropeptide amino acid sequence structures, profiling of multiple neuropeptides in normal and disease conditions, and quantitative peptide measures in biomarker applications to monitor therapeutic drug efficacies. Complementary proteomic studies of neuropeptide secretory vesicles provide valuable insight into the protein processes utilized for neuropeptide production, storage, and secretion. Furthermore, ongoing research in developing new computational tools will facilitate advancements in mass-spectrometry-based identification of small peptides. Knowledge of the entire repertoire of neuropeptides that regulate physiological systems will provide novel insight into regulatory mechanisms in health, disease, and therapeutics

    Methodological Review and Revision of the Global Hunger Index

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    Proceedings of the 3rd Biennial Conference of the Society for Implementation Research Collaboration (SIRC) 2015: advancing efficient methodologies through community partnerships and team science

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    It is well documented that the majority of adults, children and families in need of evidence-based behavioral health interventionsi do not receive them [1, 2] and that few robust empirically supported methods for implementing evidence-based practices (EBPs) exist. The Society for Implementation Research Collaboration (SIRC) represents a burgeoning effort to advance the innovation and rigor of implementation research and is uniquely focused on bringing together researchers and stakeholders committed to evaluating the implementation of complex evidence-based behavioral health interventions. Through its diverse activities and membership, SIRC aims to foster the promise of implementation research to better serve the behavioral health needs of the population by identifying rigorous, relevant, and efficient strategies that successfully transfer scientific evidence to clinical knowledge for use in real world settings [3]. SIRC began as a National Institute of Mental Health (NIMH)-funded conference series in 2010 (previously titled the “Seattle Implementation Research Conference”; $150,000 USD for 3 conferences in 2011, 2013, and 2015) with the recognition that there were multiple researchers and stakeholdersi working in parallel on innovative implementation science projects in behavioral health, but that formal channels for communicating and collaborating with one another were relatively unavailable. There was a significant need for a forum within which implementation researchers and stakeholders could learn from one another, refine approaches to science and practice, and develop an implementation research agenda using common measures, methods, and research principles to improve both the frequency and quality with which behavioral health treatment implementation is evaluated. SIRC’s membership growth is a testament to this identified need with more than 1000 members from 2011 to the present.ii SIRC’s primary objectives are to: (1) foster communication and collaboration across diverse groups, including implementation researchers, intermediariesi, as well as community stakeholders (SIRC uses the term “EBP champions” for these groups) – and to do so across multiple career levels (e.g., students, early career faculty, established investigators); and (2) enhance and disseminate rigorous measures and methodologies for implementing EBPs and evaluating EBP implementation efforts. These objectives are well aligned with Glasgow and colleagues’ [4] five core tenets deemed critical for advancing implementation science: collaboration, efficiency and speed, rigor and relevance, improved capacity, and cumulative knowledge. SIRC advances these objectives and tenets through in-person conferences, which bring together multidisciplinary implementation researchers and those implementing evidence-based behavioral health interventions in the community to share their work and create professional connections and collaborations
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