3,193 research outputs found

    Extreme ultraviolet observations of active regions in the chromosphere and the corona

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    Extreme ultraviolet observations of active regions in chromosphere and corona from OSO-4 spectroheliomete

    A balloon-borne 1 meter telescope for far-infrared astronomy

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    The flight of a balloon-borne one-meter telescope for infrared astronomy in the wavelength interval of 40 to 240 microns is discussed. The gyro-stabilized telescope mapped the intensity of the far infrared radiation from NGC 7538, Mars, the Orion Nebula, and W3 with a resolution of one minute and from selected regions of these sources with a resolution of 30 seconds. The infrared detection is described and its capabilities are analyzed. The instrumentation, orientation system, and modes of observation of the telescope are defined

    Relative photometry of HAT-P-1b occultations

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    We present HST STIS observations of two occultations of the transiting exoplanet HAT-P-1b. By measuring the planet to star flux ratio near opposition, we constrain the geometric albedo of the planet, which is strongly linked to its atmospheric temperature gradient. An advantage of HAT-P-1 as a target is its binary companion ADS 16402 A, which provides an excellent photometric reference, simplifying the usual steps in removing instrumental artifacts from HST time-series photometry. We find that without this reference star, we would need to detrend the lightcurve with the time of the exposures as well as the first three powers of HST orbital phase, and this would introduce a strong bias in the results for the albedo. However, with this reference star, we only need to detrend the data with the time of the exposures to achieve the same per-point scatter, therefore we can avoid most of the bias associated with detrending. Our final result is a 2 sigma upper limit of 0.64 for the geometric albedo of HAT-P-1b between 577 and 947 nm.Comment: 8 pages, 2 figures, 3 table

    Effects of high fat diets on milk and fat production in commercial dairy herds

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    Combined ultraviolet studies of astronomical sources

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    Ultraviolet studies of astronomical sources are discussed. Some studies utilized IVE data. Non-radiative shock at the edge of the Cygnses Loop, stellar flares, local interestellar medium, hot galaxies, stellar mass ejection, contact binaries, double quasars, and stellar chromosphere and coronae are discussed

    Detection of an Extrasolar Planet Atmosphere

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    We report high precision spectrophotometric observations of four planetary transits of HD 209458, in the region of the sodium resonance doublet at 589.3 nm. We find that the photometric dimming during transit in a bandpass centered on the sodium feature is deeper by (2.32 +/- 0.57) x 10^{-4} relative to simultaneous observations of the transit in adjacent bands. We interpret this additional dimming as absorption from sodium in the planetary atmosphere, as recently predicted from several theoretical modeling efforts. Our model for a cloudless planetary atmosphere with a solar abundance of sodium in atomic form predicts more sodium absorption than we observe. There are several possibilities that may account for this reduced amplitude, including reaction of atomic sodium into molecular gases and/or condensates, photoionization of sodium by the stellar flux, a low primordial abundance of sodium, or the presence of clouds high in the atmosphere.Comment: 26 pages, 8 figures, accepted by ApJ 2001 November 1

    Factors that impact on the use of mechanical ventilation weaning protocols in critically ill adults and children: a qualitative evidence-synthesis

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    Background Prolonged mechanical ventilation is associated with a longer intensive care unit (ICU) length of stay and higher mortality. Consequently, methods to improve ventilator weaning processes have been sought. Two recent Cochrane systematic reviews in ICU adult and paediatric populations concluded that protocols can be effective in reducing the duration of mechanical ventilation, but there was significant heterogeneity in study findings. Growing awareness of the benefits of understanding the contextual factors impacting on effectiveness has encouraged the integration of qualitative evidence syntheses with effectiveness reviews, which has delivered important insights into the reasons underpinning (differential) effectiveness of healthcare interventions. Objectives 1. To locate, appraise and synthesise qualitative evidence concerning the barriers and facilitators of the use of protocols for weaning critically-ill adults and children from mechanical ventilation; 2. To integrate this evidence with two Cochrane effectiveness reviews of protocolized weaning to help explain observed heterogeneity by identifying contextual factors that impact on the use of protocols for weaning critically-ill adults and children from mechanical ventilation; 3. To use the integrated body of evidence to suggest the circumstances in which weaning protocols are most likely to be used. Search methods We used a range of search terms identified with the help of the SPICE (Setting, Perspective, Intervention, Comparison, Evaluation) mnemonic. Where available, we used appropriate methodological filters for specific databases. We searched the following databases: Ovid MEDLINE, Embase, OVID, PsycINFO, CINAHL Plus, EBSCO Host, Web of Science Core Collection, ASSIA, IBSS, Sociological Abstracts, ProQuest and LILACS on the 26th February 2015. In addition, we searched the grey literature: the websites of professional associations for relevant publications; and the reference lists of all publications reviewed. We also contacted authors of the trials included in the effectiveness reviews as well as of studies (potentially) included in the qualitative synthesis, conducted citation searches of the publications reporting those studies and contacted content experts. We reran the search on 3rd July 2016 and found three studies, which are awaiting classification. Selection criteria We included qualitative studies that described: the circumstances in which protocols are designed, implemented or used, or both, and the views and experiences of healthcare professionals either involved in the design, implementation or use of weaning protocols or involved in the weaning of critically-ill adults and children from mechanical ventilation not using protocols. We included studies that: reflected on any aspects of the use of protocols, explored contextual factors relevant to the development, implementation or use of weaning protocols and reported contextual phenomena and outcomes identified as relevant to the effectiveness of protocolized weaning from mechanical ventilation. Data collection and analysis At each stage, two review authors undertook designated tasks, with the results shared amongst the wider team, for discussion and final development. We independently reviewed all retrieved titles, abstracts and full papers for inclusion, and independently extracted selected data from included studies. We used the findings of the included studies to develop a new set of analytical themes focused on the barriers and facilitators to the use of protocols, and further refined them to produce a set of summary statements. We used the Confidence in the Evidence from Reviews of Qualitative Research (CERQual) framework to arrive at a final assessment of the overall confidence of the evidence used in the synthesis. We included all studies but undertook two sensitivity analyses to determine how the removal of certain bodes of evidence impacted on the content and confidence of the synthesis. We deployed a logic model to integrate the findings of the qualitative evidence synthesis with those of the Cochrane effectiveness reviews. Main results We include 11 studies in our synthesis, involving 267 participants (one study did not report the number of participants). Five more studies are awaiting classification and will be dealt with when we update the review. The quality of the evidence was mixed. Of the 35 summary statement, we assessed 17 as ‘low’, 13 as ‘moderate’ and five as ‘high’ confidence. Our synthesis produced nine analytical themes, which report potential barriers and facilitators to the use of protocols. The themes are: the need for continual staff training and development; clinical experience as this promotes felt and perceived competence and confidence to wean; the vulnerability of weaning to disparate interprofessional working; an understanding of protocols as militating against a necessary proactivity in clinical practice; perceived nursing scope of practice and professional risk; ICU structure and processes of care; the ability of protocols to act as a prompt for share care and consistency in weaning practice; maximising the use of protocols through visibility and ease of implementation; and the ability of protocols to act as a frameowrk for communication with parents. Authors’ conclusions There is a clear need for weaning protocols to take account of the social and cultural environment in which they are to be implemented. Irrespective of its inherent strengths, a protocol will not be used if it does not accommodate these complexities. In terms of protocol development, comprehensive interprofessional input will help to ensure broad-based understanding and a sense of ‘ownership’. In terms of implementation, all relevant ICU staff will benefit from general weaning as well as protocol-specific training; not only will this help secure a relevant clinical knowledge base and operational understanding, but will also demonstrate to others that this knowledge and understanding is in place. In order to maximise relevance and acceptability, protocols should be designed with the patient profile and requirement of the target ICU in mind. Predictably, an under-resourced ICU will impact adversely on protocol implementation, as staff will prioritise management of acutely deteriorating and critically-ill patients
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