6,401 research outputs found

    High Spectral and Spatial Resolution Observations of Shocked Molecular Hydrogen at the Galactic Center

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    The presence of OH (1720 MHz) masers, and the absence of counterparts at 1665/1667 MHz has proved to be a clear diagnostic of shocked molecular gas associated with Galactic supernova remnants. This suggests that shocked molecular gas should be associated with the OH (1720 MHz) masers that have been detected in the circumnuclear disk (CND) and Sgr A East at the Galactic center. In order to test this hypothesis, we observed the H2_2 1--0 S(1) and Br γ\gamma lines using NICMOS on the HST and UNSWIRF on the AAT, near the regions where OH (1720 MHz) masers are detected in the CND and Sgr A East. We present the distribution of H2_2 in the North and South lobes of the CND and in Sgr A East. H2_2 emission accompanies almost all of the maser spots detected at the Galactic center. In particular, we find a striking filamentary structure near the Northwest of the CND and evidence that shocked molecular gas is associated with the 70 \kms molecular cloud at the Galactic center. We argue that the emission from the CND could arise in gas heated by the dissipation of the random motion of clumps by collisions or the dissipation of turbulence in a more homogeneous medium. In addition, highly red-shifted gas of up to 140 \kms\ close to the eastern edge of the Sgr A East shell is detected. These observations combined with OH (1720 MHz) results suggest that the H2_2 gas is shocked and accelerated by the expansion of Sgr A East into the 50 and the 70 \kms cloud and into the lobes of the CND.Comment: 31 pages plus 14 figures, ApJ (in press

    SOME LEGAL PROBLEMS CONNECTED WITH STOCK MARKET TRANSACTIONS

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    If any one were asked what was the most dramatic event of the last year, he probably refer at once to the collapse of the great Bull Market on the New York Stock Exchange. This was not only a dramatic event, but it was literally a tragedy for hundreds of thousands of people. Securities shrank to less than half their former inflated values and hundreds of millions of dollars in cash and paper profits were lost over night, or possibly we should say over two nights, for the crash occurred in two stages, one in October and one in November, and many of those who staggered through the first were annihilated by the second. Never before had so many people been involved in stock market speculation, and, consequently, never before had so many people been directly hit by any stock market panic. Never before had so many dreams of El Dorado been shattered

    Kinematic dynamo action in a sphere: Effects of periodic time-dependent flows on solutions with axial dipole symmetry

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    Choosing a simple class of flows, with characteristics that may be present in the Earth's core, we study the ability to generate a magnetic field when the flow is permitted to oscillate periodically in time. The flow characteristics are parameterised by D, representing a differential rotation, M, a meridional circulation, and C, a component characterising convective rolls. Dynamo action is sensitive to these flow parameters and fails spectacularly for much of the parameter space where magnetic flux is concentrated into small regions. Oscillations of the flow are introduced by varying the flow parameters in time, defining a closed orbit in the space (D,M). Time-dependence appears to smooth out flux concentrations, often enhancing dynamo action. Dynamo action can be impaired, however, when flux concentrations of opposite signs occur close together as smoothing destroys the flux by cancellation. It is possible to produce geomagnetic-type reversals by making the orbit stray into a region where the steady flows generate oscillatory fields. In this case, however, dynamo action was not found to be enhanced by the time-dependence. A novel approach is taken to solving the time-dependent eigenvalue problem, where by combining Floquet theory with a matrix-free Krylov-subspace method we avoid large memory requirements for storing the matrix required by the standard approach.Comment: 22 pages, 12 figures. Geophys. Astrophys. Fluid Dynam., as accepted (2004

    A Wide-Field CCD Survey for Centaurs and Kuiper Belt Objects

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    A modified Baker-Nunn camera was used to conduct a wide-field survey of 1428 square degrees of sky near the ecliptic in search of bright Kuiper Belt objects and Centaurs. This area is an order of magnitude larger than any previously published CCD survey for Centaurs and Kuiper Belt Objects. No new objects brighter than red magnitude m=18.8 and moving at a rate 1"/hr to 20"/hr were discovered, although one previously discovered Centaur 1997 CU26 Chariklo was serendipitously detected. The parameters of the survey were characterized using both visual and automated techniques. From this survey the empirical projected surface density of Centaurs was found to be SigmaCentaur(m<18.8)=7.8(+16.0 -6.6)x10^-4 per square degree and we found a projected surface density 3sigma upper confidence limit for Kuiper Belt objects of SigmaKBO(m< 18.8)<4.1x10^-3 per square degree. We discuss the current state of the cumulative luminosity functions of both Centaurs and Kuiper Belt objects. Through a Monte Carlo simulation we show that the size distribution of Centaurs is consistent with a q=4 differential power law, similar to the size distribution of the parent Kuiper Belt Objects. The Centaur population is of order 10^7 (radius > 1 km) assuming a geometric albedo of 0.04. About 100 Centaurs are larger than 50 km in radius, of which only 4 are presently known. The current total mass of the Centaurs is 10^-4 Earth Masses. No dust clouds were detected resulting from Kuiper Belt object collisions, placing a 3sigma upper limit <600 collisionally produced clouds of m<18.8 per year.Comment: 13 pages, 5 figures, Accepted for Publication in A

    A theoretically based cross-sectional survey on the behaviors and experiences of clinical pharmacists caring for patients with chronic kidney disease.

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    The literature shows a lack of evidence on pharmacists contributing to chronic kidney disease services. The aim was to determine pharmacists’ behaviors and experiences and perceptions of barriers and facilitators to implementation of models of care. A theoretically informed survey was developed and sent to pharmacist members of the United Kingdom renal pharmacy group. Sections included: demographics, clinical practice and prescribing practice. Questions were of various types; closed type and some open for comments. Attitudinal items on clinical/prescribing used 5-point Likert scale. Development/implementation items were derived from the Consolidated Framework for Implementation Research (CFIR). Analysis used descriptive statistics and open comments were analysed thematically. Ethical approval was granted by an academic institution. Response rate; 50% (n = 71), seven were incomplete and excluded. Respondents provided; inpatient general pharmaceutical care (n = 56, 87.5%), to those receiving dialysis (n = 54, 84.4%) and transplantation. Non-clinical roles; audits (n = 46, 71.9%), patient education (n = 31, 48.4%), only 7.8% (n = 5) doing academic research. For barrier/facilitators most strongly agreed/agreed with most CFIR items relating to clinical practice. A majority (n = 44, 68.7%) disagreed that they had sufficient time to practice clinically and 44 (68.7%) disagreed there was sufficient cover for services. For prescribing roles, 90.5% (n = 48) were currently actively prescribing. Although prescribing related CFIR items were largely positive, 39.6% (n = 19) disagreed about sufficient time to practice and 18.7% (n = 9) were neutral. Two thirds (n = 33, 68.7%) disagreed that there was sufficient cover for the prescribing. The majority of respondents provided general pharmaceutical care to dialysis and transplant patients, were confident in their abilities and tried new ways of working including independent prescribing. Many expressed that lack of resources was the main barrier to providing more advanced care. Further work is needed to explore these matters in more depth

    Moving interpretations : using drama-based arts strategies to deepen learning about The diary of a young girl.

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    Three drama-based arts strategies enhanced middle grades teachers’ and students’ engagement with Anne Frank’s diary and historical circumstances

    Efficacy and effectiveness of dihydroartemisinin-piperaquine versus artesunate-mefloquine in falciparum malaria: an open-label randomised comparison.

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    BACKGROUND: Artemisinin-based combinations are judged the best treatments for multidrug-resistant Plasmodium falciparum malaria. Artesunate-mefloquine is widely recommended in southeast Asia, but its high cost and tolerability profile remain obstacles to widespread deployment. To assess whether dihydroartemisinin-piperaquine is a suitable alternative to artesunate-mefloquine, we compared the safety, tolerability, efficacy, and effectiveness of the two regimens for the treatment of uncomplicated falciparum in western Myanmar (Burma). METHODS: We did an open randomised comparison of 3-day regimens of artesunate-mefloquine (12/25 mg/kg) versus dihydroartemisinin-piperaquine (6.3/50 mg/kg) for the treatment of children aged 1 year or older and in adults with uncomplicated falciparum malaria in Rakhine State, western Myanmar. Within each group, patients were randomly assigned supervised or non-supervised treatment. The primary endpoint was the PCR-confirmed parasitological failure rate by day 42. Failure rates at day 42 were estimated by Kaplan-Meier survival analysis. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN27914471. FINDINGS: Of 652 patients enrolled, 327 were assigned dihydroartemisinin-piperaquine (156 supervised and 171 not supervised), and 325 artesunate-mefloquine (162 and 163, respectively). 16 patients were lost to follow-up, and one patient died 22 days after receiving dihydroartemisinin-piperaquine. Recrudescent parasitaemias were confirmed in only two patients; the day 42 failure rate was 0.6% (95% CI 0.2-2.5) for dihydroartemisinin-piperaquine and 0 (0-1.2) for artesunate-mefloquine. Whole-blood piperaquine concentrations at day 7 were similar for patients with observed and non-observed dihydroartemisinin-piperaquine treatment. Gametocytaemia developed more frequently in patients who had received dihydroartemisinin-piperaquine than in those on artesunate-mefloquine: day 7, 18 (10%) of 188 versus five (2%) of 218; relative risk 4.2 (1.6-11.0) p=0.011. INTERPRETATION: Dihydroartemisinin-piperaquine is a highly efficacious and inexpensive treatment of multidrug-resistant falciparum malaria and is well tolerated by all age groups. The effectiveness of the unsupervised treatment, as in the usual context of use, equalled its supervised efficacy, indicating good adherence without supervision. Dihydroartemisinin-piperaquine is a good alternative to artesunate-mefloquine

    ‘Engage the World’: examining conflicts of engagement in public museums

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    Public engagement has become a central theme in the mission statements of many cultural institutions, and in scholarly research into museums and heritage. Engagement has emerged as the go-to-it-word for generating, improving or repairing relations between museums and society at large. But engagement is frequently an unexamined term that might embed assumptions and ignore power relationships. This article describes and examines the implications of conflicting and misleading uses of ‘engagement’ in relation to institutional dealings with contested questions about culture and heritage. It considers the development of an exhibition on the Dead Sea Scrolls by the Royal Ontario Museum, Toronto in 2009 within the new institutional goal to ‘Engage the World’. The chapter analyses the motivations, processes and decisions deployed by management and staff to ‘Engage the World’, and the degree to which the museum was able to re-think its strategies of public engagement, especially in relation to subjects,issues and publics that were more controversial in nature
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