254 research outputs found

    Faint Infrared Flares from the Microquasar GRS 1915+105

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    We present simultaneous infrared and X-ray observations of the Galactic microquasar GRS 1915+105 using the Palomar 5-m telescope and Rossi X-ray Timing Explorer on July 10, 1998 UT. Over the course of 5 hours, we observed 6 faint infrared (IR) flares with peak amplitudes of 0.30.6\sim 0.3-0.6 mJy and durations of 500600\sim 500-600 seconds. These flares are associated with X-ray soft-dip/soft-flare cycles, as opposed to the brighter IR flares associated with X-ray hard-dip/soft-flare cycles seen in August 1997 by Eikenberry et al. (1998). Interestingly, the IR flares begin {\it before} the X-ray oscillations, implying an ``outside-in'' origin of the IR/X-ray cycle. We also show that the quasi-steady IR excess in August 1997 is due to the pile-up of similar faint flares. We discuss the implications of this flaring behavior for understanding jet formation in microquasars.Comment: 10 pages, 4 figures Accepted for publication in ApJ Letter

    Methods for the thematic synthesis of qualitative research in systematic reviews

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    <p>Abstract</p> <p>Background</p> <p>There is a growing recognition of the value of synthesising qualitative research in the evidence base in order to facilitate effective and appropriate health care. In response to this, methods for undertaking these syntheses are currently being developed. Thematic analysis is a method that is often used to analyse data in primary qualitative research. This paper reports on the use of this type of analysis in systematic reviews to bring together and integrate the findings of multiple qualitative studies.</p> <p>Methods</p> <p>We describe thematic synthesis, outline several steps for its conduct and illustrate the process and outcome of this approach using a completed review of health promotion research. Thematic synthesis has three stages: the coding of text 'line-by-line'; the development of 'descriptive themes'; and the generation of 'analytical themes'. While the development of descriptive themes remains 'close' to the primary studies, the analytical themes represent a stage of interpretation whereby the reviewers 'go beyond' the primary studies and generate new interpretive constructs, explanations or hypotheses. The use of computer software can facilitate this method of synthesis; detailed guidance is given on how this can be achieved.</p> <p>Results</p> <p>We used thematic synthesis to combine the studies of children's views and identified key themes to explore in the intervention studies. Most interventions were based in school and often combined learning about health benefits with 'hands-on' experience. The studies of children's views suggested that fruit and vegetables should be treated in different ways, and that messages should not focus on health warnings. Interventions that were in line with these suggestions tended to be more effective. Thematic synthesis enabled us to stay 'close' to the results of the primary studies, synthesising them in a transparent way, and facilitating the explicit production of new concepts and hypotheses.</p> <p>Conclusion</p> <p>We compare thematic synthesis to other methods for the synthesis of qualitative research, discussing issues of context and rigour. Thematic synthesis is presented as a tried and tested method that preserves an explicit and transparent link between conclusions and the text of primary studies; as such it preserves principles that have traditionally been important to systematic reviewing.</p

    Longitudinal conjunction between MESSENGER and STEREO A: Development of ICME complexity through stream interactions

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    We use data on an interplanetary coronal mass ejection (ICME) seen by MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and STEREO A starting on 29 December 2011 in a near‐perfect longitudinal conjunction (within 3°) to illustrate changes in its structure via interaction with the solar wind in less than 0.6 AU. From force‐free field modeling we infer that the orientation of the underlying flux rope has undergone a rotation of ∼80° in latitude and ∼65° in longitude. Based on both spacecraft measurements as well as ENLIL model simulations of the steady state solar wind, we find that interaction involving magnetic reconnection with corotating structures in the solar wind dramatically alters the ICME magnetic field. In particular, we observed a highly turbulent region with distinct properties within the flux rope at STEREO A, not observed at MESSENGER, which we attribute to interaction between the ICME and a heliospheric plasma sheet/current sheet during propagation. Our case study is a concrete example of a sequence of events that can increase the complexity of ICMEs with heliocentric distance even in the inner heliosphere. The results highlight the need for large‐scale statistical studies of ICME events observed in conjunction at different heliocentric distances to determine how frequently significant changes in flux rope orientation occur during propagation. These results also have significant implications for space weather forecasting and should serve as a caution on using very distant observations to predict the geoeffectiveness of large interplanetary transients.Key PointsICME complexity increases due to interaction with corotating structures in the solar windMagnetic reconnection between ICME and HPS/HCS alters the magnetic topology of the ICME flux ropeCaution on using distant observations to predict the geoeffectiveness of interplanetary transientsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134123/1/jgra52739.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134123/2/jgra52739_am.pd

    The medical student

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    The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

    Pulp, Vol. 2 No. 1

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    This is the second issue of Pulp.https://scholarworks.sfasu.edu/pulp/1001/thumbnail.jp

    Pulp, Vol. 2 No. 1

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    This is the second issue of Pulp.https://scholarworks.sfasu.edu/pulp/1001/thumbnail.jp

    Humility, Self-Awareness, and Religious Ambivalence: Another Look at Beckett's ‘Humanistic Quietism’

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    This is the accepted manuscript. The final version is available from Edinburgh University Press at http://www.euppublishing.com/doi/abs/10.3366/jobs.2014.0104. This article provides a commentary on the opaque and often contradictory arguments of ‘Humanistic Quietism’, Samuel Beckett's 1934 review of Thomas MacGreevy's Poems. Using Beckett's complicated relationship to both his own Protestant upbringing and the Catholicism of MacGreevy as a starting point, the article proposes new ways of understanding Beckett's ambivalent comments about MacGreevy's interiority, prayer-like poetry, humility, and quietism. It draws on Beckett's comments on Rilke, André Gide, and Arnold Geulincx, as well as his familiarity with Dante, to unpack the review's dense allusions and make sense of Beckett's aesthetic allegiances. </jats:p

    Valuing breastfeeding: a qualitative study of women's experiences of a financial incentive scheme for breastfeeding

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    BACKGROUND: A cluster randomised controlled trial of a financial incentive for breastfeeding conducted in areas with low breastfeeding rates in the UK reported a statistically significant increase in breastfeeding at 6-8 weeks. In this paper we report an analysis of interviews with women eligible for the scheme, exploring their experiences and perceptions of the scheme and its impact on breastfeeding to support the interpretation of the results of the trial. METHODS: Semi-structured interviews were carried out with 35 women eligible for the scheme during the feasibility and trial stages. All interviews were recorded and verbatim transcripts analysed using a Framework Analysis approach. RESULTS: Women reported that their decisions about infant feeding were influenced by the behaviours and beliefs of their family and friends, socio-cultural norms and by health and practical considerations. They were generally positive about the scheme, and felt valued for the effort involved in breastfeeding. The vouchers were frequently described as a reward, a bonus and something to look forward to, and helping women keep going with their breastfeeding. They were often perceived as compensation for the difficulties women encountered during breastfeeding. The scheme was not thought to make a difference to mothers who were strongly against breastfeeding. However, women did believe the scheme would help normalise breastfeeding, influence those who were undecided and help women to keep going with breastfeeding and reach key milestones e.g. 6 weeks or 3 months. CONCLUSIONS: The scheme was acceptable to women, who perceived it as rewarding and valuing them for breastfeeding. Women reported that the scheme could raise awareness of breastfeeding and encourage its normalisation. This provides a possible mechanism of action to explain the results of the trial. TRIAL REGISTRATION: The trial is registered with the ISRCTN registry, number 44898617 , https://www.isrctn.com

    Application of Spatial Data Modeling and Geographical Information Systems (GIS) for Identification of Potential Siting Options for Various Electrical Generation Sources

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    Oak Ridge National Laboratory (ORNL) initiated an internal National Electric Generation Siting Study, which is an ongoing multiphase study addressing several key questions related to our national electrical energy supply. This effort has led to the development of a tool, OR-SAGE (Oak Ridge Siting Analysis for power Generation Expansion), to support siting evaluations. The objective in developing OR-SAGE was to use industry-accepted approaches and/or develop appropriate criteria for screening sites and employ an array of Geographic Information Systems (GIS) data sources at ORNL to identify candidate areas for a power generation technology application. The initial phase of the study examined nuclear power generation. These early nuclear phase results were shared with staff from the Electric Power Research Institute (EPRI), which formed the genesis and support for an expansion of the work to several other power generation forms, including advanced coal with carbon capture and storage (CCS), solar, and compressed air energy storage (CAES). Wind generation was not included in this scope of work for EPRI. The OR-SAGE tool is essentially a dynamic visualization database. The results shown in this report represent a single static set of results using a specific set of input parameters. In this case, the GIS input parameters were optimized to support an economic study conducted by EPRI. A single set of individual results should not be construed as an ultimate energy solution, since US energy policy is very complex. However, the strength of the OR-SAGE tool is that numerous alternative scenarios can be quickly generated to provide additional insight into electrical generation or other GIS-based applications. The screening process divides the contiguous United States into 100 x 100 m (1-hectare) squares (cells), applying successive power generation-appropriate site selection and evaluation criteria (SSEC) to each cell. There are just under 700 million cells representing the contiguous United States. If a cell meets the requirements of each criterion, the cell is deemed a candidate area for siting a specific power generation form relative to a reference plant for that power type. Some SSEC parameters preclude siting a power plant because of an environmental, regulatory, or land-use constraint. Other SSEC assist in identifying less favorable areas, such as proximity to hazardous operations. All of the selected SSEC tend to recommend against sites. The focus of the ORNL electrical generation source siting study is on identifying candidate areas from which potential sites might be selected, stopping short of performing any detailed site evaluations or comparisons. This approach is designed to quickly screen for and characterize candidate areas. Critical assumptions supporting this work include the supply of cooling water to thermoelectric power generation; a methodology to provide an adequate siting footprint for typical power plant applications; a methodology to estimate thermoelectric plant capacity while accounting for available cooling water; and a methodology to account for future ({approx}2035) siting limitations as population increases and demands on freshwater sources change. OR-SAGE algorithms were built to account for these critical assumptions. Stream flow is the primary thermoelectric plant cooling source evaluated in this study. All cooling was assumed to be provided by a closed-cycle cooling (CCC) system requiring makeup water to account for evaporation and blowdown. Limited evaluations of shoreline cooling and the use of municipal processed water (gray) cooling were performed. Using a representative set of SSEC as input to the OR-SAGE tool and employing the accompanying critical assumptions, independent results for the various power generation sources studied were calculated

    The terrain of health policy analysis in low and middle income countries: a review of published literature 1994–2007

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    This article provides the first ever review of literature analysing the health policy processes of low and middle income countries (LMICs). Based on a systematic search of published literature using two leading international databases, the article maps the terrain of work published between 1994 and 2007, in terms of policy topics, lines of inquiry and geographical base, as well as critically evaluating its strengths and weaknesses. The overall objective of the review is to provide a platform for the further development of this field of work
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