2,753 research outputs found

    Effects of Volcanic Emissions on Clouds During Kilauea Degassing Events

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    Aerosols influence Earths radiative balance directly by scattering and absorbing solar radiation, and indirectly by modifying cloud properties. Current scientific consensus indicates that these effects may offset as much as 50% of the warming due to greenhouse gas emissions. Over the last two decades dramatic volcanic events in Hawaii have produced localized aerosol emissions in otherwise clean environments. These are natural experiments" where the aerosol effects on clouds and climate can be partitioned from other effects like meteorology and industrial emissions. Therefore, these events provide a unique opportunity to learn about possible effects of aerosol pollution on climate through cloud modification. In this work we use the version 5 of the NASA Goddard Earth Observing System (GEOS-5) and satellite retrievals to analyze and evaluate the strength of the aerosol indirect effect on liquid and ice clouds during the 2008 and 2018 Kilauea degassing events using different emissions scenarios (0, 1, and 5 actual emissions). Our results suggested that the 2018 event was stronger and more regionally significant with respect to cloud formation process for both liquid and ice clouds, while the 2008 affected local liquid clouds only. GEOS-5 predictions reproduced spatial patterns for all parameters, however better precision could be gained by using more accurate plume parameters for height and ash concentration

    Principal 2-bundles and their gauge 2-groups

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    In this paper we introduce principal 2-bundles and show how they are classified by non-abelian Cech cohomology. Moreover, we show that their gauge 2-groups can be described by 2-group-valued functors, much like in classical bundle theory. Using this, we show that, under some mild requirements, these gauge 2-groups possess a natural smooth structure. In the last section we provide some explicit examples.Comment: 40 pages; v3: completely revised and extended, classification corrected, name changed, to appear in Forum Mat

    Interdisciplinary Perspectives on Restraint Use in Aged Care.

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    Restraint use in Australian residential aged care has been highlighted by the media, and investigated by researchers, government and advocacy bodies. In 2018, the Royal Commission into Aged Care selected 'Restraint' as a key focus of inquiry. Subsequently, Federal legislation was passed to ensure restraint is only used in residential aged care services as the 'last resort'. To inform and develop Government educational resources, we conducted qualitative research to gain greater understanding of the experiences and attitudes of aged care stakeholders around restraint practice. Semi-structured interviews were held with 28 participants, comprising nurses, care staff, physicians, physiotherapists, pharmacists and relatives. Two focus groups were also conducted to ascertain the views of residential and community aged care senior management staff. Data were thematically analyzed using a pragmatic approach of inductive and deductive coding and theme development. Five themes were identified during the study: 1. Understanding of restraint; 2. Support for legislation; 3. Restraint-free environments are not possible; 4. Low-level restraint; 5. Restraint in the community is uncharted. Although most staff, health practitioners and relatives have a basic understanding of restraint, more education is needed at a conceptual level to enable them to identify and avoid restraint practice, particularly 'low-level' forms and chemical restraint. There was strong support for the new restraint regulations, but most interviewees admitted they were unsure what the legislation entailed. With regards to resources, stakeholders wanted recognition that there were times when restraint was necessary and advice on what to do in these situations, as opposed to unrealistic aspirations for restraint-free care. Stakeholders reported greater oversight of restraint in residential aged care but specified that community restraint use was largely unknown. Research is needed to investigate the extent and types of restraint practice in community aged care

    Pericardial Thickness Measured With Transesophageal Echocardiography: Feasibility and Potential Clinical Usefulness

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    AbstractObjectives. This study assessed the reliability of transesophageal echocardiographic measurements of pericardial thickness and the potential diagnostic usefulness of this technique.Background. Transthoracic echocardiography cannot reliably detect thickened pericardium. The superior resolution achieved with transesophageal echocardiography should allow better pericardial definition.Methods. Pericardial thickness measured at 26 locations in 11 patients with constrictive pericarditis who underwent intraoperative transesophageal echocardiography was compared with pericardial thickness measured with electron beam computed tomography. Intraobserver and interobserver variabilities were determined. Pericardial thickness was then measured in 21 normal subjects. With these values as a guide, two observers reviewed 37 transesophageal echocardiographic studies to determine whether echocardiographic measurement of pericardial thickness could be used to distinguish diseased from normal pericardium.Results. The correlation between echocardiographic and computed tomographic measurements (r ≥ 0.95, SE ≤ 0.06 mm, p < 0.0001) was excellent. The ±2 SD limits of agreement were ±1.0 mm or less for pericardial thickness <5.5 mm and ±2.0 mm or less for the entire range of thicknesses. Intraobserver and interobserver agreements were good. Mean normal pericardial thickness was 1.2 ± 0.8 mm (±2 SD) and did not exceed 2.5 mm. Pericardial thickness ≥3 mm on transesophageal echocardiography was 95% sensitive and 86% specific for the detection of thickened pericardium.Conclusions. Measurement of pericardial thickness with transesophageal echocardiography is reproducible and should be a valuable adjunct in assessing constrictive pericarditis.(J Am Coll Cardiol 1997;29:1317–23

    Survey sequencing and radiation hybrid mapping to construct comparative maps.

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    In MURPHY WJ (ed.) Phylogenomics, Humana Press. (Methods in Molecular Biology, 422)International audienceRadiation hybrid (RH) mapping has become one of the most well-established techniques for economically and efficiently navigating genomes of interest. The success of the technique relies on random chromosome breakage of a target genome, which is then captured by recipient cells missing a preselected marker. Selection for hybrid cells that have DNA fragments bearing the marker of choice, plus a random set of DNA fragments from the initial irradiation, generates a set of cell lines that recapitulates the genome of the target organism several-fold. Markers or genes of interest are analyzed by PCR using DNA isolated from each cell line. Statistical tools are applied to determine both the linear order of markers on each chromosome, and the confidence of each placement. The resolution of the resulting map relies on many factors, most notably the degree of breakage from the initial radiation as well as the number of hybrid clones and mean retention value.A high-resolution RH map of a genome derived from low pass or survey sequencing (coverage from 1 to 2 times) can provide essentially the same comparative data on gene order that is derived from high-coverage (greater than x7) genome sequencing. When combined with fluorescence in situ hybridization, RH maps are complete and ordered blueprints for each chromosome. They give information about the relative order and spacing of genes and markers, and allow investigators to move between target and reference genomes, such as those of mouse or human, with ease although the approach is not limited to mammal genomes

    Long-term clinical outcomes in survivors of severe acute respiratory syndrome and Middle East respiratory syndrome coronavirus outbreaks after hospitalisation or ICU admission: a systematic review and meta-analysis

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    Objective: To determine long-term clinical outcomes in survivors of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronavirus infections after hospitalization or intensive care unit admission. Data sources: Ovid MEDLINE, EMBASE, CINAHL Plus, and PsycINFO were searched. Study selection: Original studies reporting clinical outcomes of adult SARS and MERS survivors 3 months after admission or 2 months after discharge were included. Data extraction: Studies were graded using the Oxford Centre for Evidence-Based Medicine 2009 Level of Evidence Tool. Meta-analysis was used to derive pooled estimates for prevalence/severity of outcomes up to 6 months after hospital discharge, and beyond 6 months after discharge. Data synthesis: Of 1,169 identified studies, 28 were included in the analysis. Pooled analysis revealed that common complications up to 6 months after discharge were: impaired diffusing capacity for carbon monoxide (prevalence 27%, 95% confidence interval (CI) 15–45%); and reduced exercise capacity (mean 6-min walking distance 461 m, CI 450–473 m). The prevalences of post-traumatic stress disorder (39%, 95% CI 31–47%), depression (33%, 95% CI 20–50%) and anxiety (30%, 95% CI 10–61) beyond 6 months after discharge were considerable. Low scores on Short-Form 36 were identified beyond 6 months after discharge. Conclusion: Lung function abnormalities, psychological impairment and reduced exercise capacity were common in SARS and MERS survivors. Clinicians should anticipate and investigate similar long-term outcomes in COVID-19 survivors

    Intermittent maser flare around the high mass young stellar object G353.273+0.641 I: data & overview

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    We have performed VLBI and single-dish monitoring of 22 GHz H2_{2}O maser emission from the high mass young stellar object G353.273+0.641 with VERA (VLBI Exploration of Radio Astrometry) and Tomakamai 11-m radio telescope. Two maser flares have been detected, separated almost two years. Frequent VLBI monitoring has revealed that these flare activities have been accompanied by structural change of the prominent shock front traced by H2O maser alignments. We have detected only blue-shifted emissions and all maser features have been distributed within very small area of 200 ×\times 200 au2^{2} in spite of wide velocity range (> 100 km s−1^{-1}). The light curve shows notably intermittent variation and suggests that the H2_{2}O masers in G353.273+0.641 are excited by episodic radio jet. The time-scale of \sim2 yr and characteristic velocity of \sim500 km s−1^{-1} also support this interpretation. Two isolated velocity components of C50 (-53 \pm 7 km s−1^{-1}) and C70 (-73 \pm 7 km s−1^{-1}) have shown synchronised linear acceleration of the flux weighted V_{\rmn{LSR}} values (\sim-5 km s−1^{-1} yr−1^{-1}) during the flare phase. This can be converted to the lower-limit momentum rate of 1.1 \times 10−3^{-3} M_{\sun} km s−1^{-1} yr−1^{-1}. Maser properties are quite similar to that of IRAS 20126+4104 especially. This corroborates the previous suggestion that G353.273+0.641 is a candidate of high mass protostellar object. The possible pole-on geometry of disc-jet system can be suitable for direct imaging of the accretion disc in this case.Comment: 13 pages, 5 figures accepted for publication in MNRA

    L∞L_\infty-Algebras, the BV Formalism, and Classical Fields

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    We summarise some of our recent works on L∞L_\infty-algebras and quasi-groups with regard to higher principal bundles and their applications in twistor theory and gauge theory. In particular, after a lightning review of L∞L_\infty-algebras, we discuss their Maurer-Cartan theory and explain that any classical field theory admitting an action can be reformulated in this context with the help of the Batalin-Vilkovisky formalism. As examples, we explore higher Chern-Simons theory and Yang-Mills theory. We also explain how these ideas can be combined with those of twistor theory to formulate maximally superconformal gauge theories in four and six dimensions by means of L∞L_\infty-quasi-isomorphisms, and we propose a twistor space action.Comment: 19 pages, Contribution to Proceedings of LMS/EPSRC Durham Symposium Higher Structures in M-Theory, August 201
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