640 research outputs found

    Discovery of a Quadruple Lens in CANDELS with a Record Lens Redshift z=1.53

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    Using spectroscopy from the Large Binocular Telescope and imaging from the Hubble Space Telescope we discovered the first strong galaxy lens at z(lens)>1. The lens has a secure photometric redshift of z=1.53+/-0.09 and the source is spectroscopically confirmed at z=3.417. The Einstein radius (0.35"; 3.0 kpc) encloses 7.6 x 10^10 Msol, with an upper limit on the dark matter fraction of 60%. The highly magnified (40x) source galaxy has a very small stellar mass (~10^8 Msol) and shows an extremely strong [OIII]_5007A emission line (EW_0 ~ 1000A) bolstering the evidence that intense starbursts among very low-mass galaxies are common at high redshift.Comment: accepted for publication in ApJ Letter

    Raman Spectroscopy Study of alpha-, beta-, gamma-NaxCoO2 and gamma-(Ca,Sr)xCoO2

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    Raman spectroscopy measurements have been performed on alpha-, beta-, gamma-NaxCoO2 phases differing in their stacking of CoO6 octahedra along the c-axis direction. The results demonstrate that, in general, there are five active phonons for gamma-Na0.75CoO2, two Raman active phonons for alpha-NaCoO2, and four Raman active phonons for beta-NaCoO2. We have also performed Raman scattering measurements on several gamma-(Ca,Sr)xCoO2 (0.15 <= x <= 0.35) samples which show well-defined intercalated Ca/Sr-ordering. The experimental data show that the intercalated cation ordering could result in visible alterations on Raman spectral structures. The observations of the spectral changes along with the variation of the CoO6 stacking, as well as the intercalated Sr/Ca ordering suggest that the interlayer interaction plays an important role for understanding the lattice dynamics in this layered system.Comment: 23 pages, 5 figures, Physical Review B, in pres

    An evaluation of DSM-III-R and ICD-10 benzodiazepine dependence criteria using Rasch modelling

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    Abstract Aims. To evaluate the homogeneity of the elements of the Substance Dependence Syndrome (SDS) as applied to benzodiazepines (BZD

    Monitoring, management, and outcome of hypotension in Intensive Care Unit patients, an international survey of the European Society of Intensive Care Medicine

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    INTRODUCTION: Hypotension in the ICU is common, yet management is challenging and variable. Insight in management by ICU physicians and nurses may improve patient care and guide future hypotension treatment trials and guidelines. METHODS: We conducted an international survey among ICU personnel to provide insight in monitoring, management, and perceived consequences of hypotension. RESULTS: Out of 1464 respondents, 1197 (81.7%) were included (928 physicians (77.5%) and 269 nurses (22.5%)). The majority indicated that hypotension is underdiagnosed (55.4%) and largely preventable (58.8%). Nurses are primarily in charge of monitoring changes in blood pressure, physicians are in charge of hypotension treatment. Balanced crystalloids, dobutamine, norepinephrine, and Trendelenburg position were the most frequently reported fluid, inotrope, vasopressor, and positional maneuver used to treat hypotension. Reported complications believed to be related to hypotension were AKI and myocardial injury. Most ICUs do not have a specific hypotension treatment guideline or protocol (70.6%), but the majority would like to have one in the future (58.1%). CONCLUSIONS: Both physicians and nurses report that hypotension in ICU patients is underdiagnosed, preventable, and believe that hypotension influences morbidity. Hypotension management is generally not protocolized, but the majority of respondents would like to have a specific hypotension management protocol

    Definition and incidence of hypotension in intensive care unit patients, an international survey of the European Society of Intensive Care Medicine

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    Introduction: Although hypotension in ICU patients is associated with adverse outcome, currently used definitions are unknown and no universally accepted definition exists. Methods: We conducted an international, peer-reviewed survey among ICU physicians and nurses to provide insight in currently used definitions, estimations of incidence, and duration of hypotension. Results: Out of 1394 respondents (1055 physicians (76%) and 339 nurses (24%)), 1207 (82%) completed the questionnaire. In all patient categories, hypotension definitions were predominantly based on an absolute MAP of 65 mmHg, except for the neuro(trauma) category (75 mmHg, p &lt; 0.001), without differences between answers from physicians and nurses. Hypotension incidence was estimated at 55%, and time per day spent in hypotension at 15%, both with nurses reporting higher percentages than physicians (estimated mean difference 5%, p = 0.01; and 4%, p &lt; 0.001). Conclusions: An absolute MAP threshold of 65 mmHg is most frequently used to define hypotension in ICU patients. In neuro(trauma) patients a higher threshold was reported. The majority of ICU patients are estimated to endure hypotension during their ICU admission for a considerable amount of time, with nurses reporting a higher estimated incidence and time spent in hypotension than physicians.</p

    The Effect of Lattice Vibrations on Substitutional Alloy Thermodynamics

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    A longstanding limitation of first-principles calculations of substitutional alloy phase diagrams is the difficulty to account for lattice vibrations. A survey of the theoretical and experimental literature seeking to quantify the impact of lattice vibrations on phase stability indicates that this effect can be substantial. Typical vibrational entropy differences between phases are of the order of 0.1 to 0.2 k_B/atom, which is comparable to the typical values of configurational entropy differences in binary alloys (at most 0.693 k_B/atom). This paper describes the basic formalism underlying ab initio phase diagram calculations, along with the generalization required to account for lattice vibrations. We overview the various techniques allowing the theoretical calculation and the experimental determination of phonon dispersion curves and related thermodynamic quantities, such as vibrational entropy or free energy. A clear picture of the origin of vibrational entropy differences between phases in an alloy system is presented that goes beyond the traditional bond counting and volume change arguments. Vibrational entropy change can be attributed to the changes in chemical bond stiffness associated with the changes in bond length that take place during a phase transformation. This so-called ``bond stiffness vs. bond length'' interpretation both summarizes the key phenomenon driving vibrational entropy changes and provides a practical tool to model them.Comment: Submitted to Reviews of Modern Physics 44 pages, 6 figure

    Determination of masses of the central black holes in NGC524 and NGC2549 using Laser Guide Star Adaptive Optics

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    [abridged] We present observations of NGC524 and NGC2549 with LGS AO obtained at GEMINI North telescope using the NIFS IFU in the K band. The purpose of these observations, together with previously obtained observations with the SAURON IFU, is to determine the masses (Mbh) of the supermassive black holes (SMBH). The targeted galaxies were chosen to have central light profiles showing a core (NGC524) and a cusp (NGC2549), to probe the feasibility of using the galaxy centre as the NGS required for LGS AO. We employ an innovative `open loop' technique. The data have spatial resolution of 0.23" and 0.17" FWHM, showing that high quality LGS AO observations of these objects are possible. We construct axisymmetric three-integral dynamical models which are constrained with both the NIFS and SAURON data. The best fitting models yield Mbh=(8.3 +2.7 -1.3) x 10^8 Msun for NGC524 and Mbh=(1.4 +0.2 -1.3) x 10^7 Msun for NGC2549 (all errors are at the 3 sigma CL). We demonstrate that the wide-field SAURON data play a crucial role in the M/L determination increasing the accuracy of M/L by a factor of at least 5, and constraining the upper limits on Mbh. The NIFS data are crucial in constraining the lower limits of Mbh and in combination with the large scale data reducing the uncertainty by a factor of 2 or more. We find that the orbital structure of NGC524 shows significant tangential anisotropy, while at larger radii both galaxies are consistent with having almost perfectly oblate velocity ellipsoids. Tangential anisotropy in NGC524 coincides with the size of SMBH sphere of influence and the core region in the light profile. We test the accuracy to which Mbh can be measured using seeings obtained from typical LGS AO observations, and conclude that for a typical conditions and Mbh the expected uncertainty is of the order of 50%.Comment: 19 pages, 14 figure

    The Dutch Consumer Quality Index: an example of stakeholder involvement in indicator development

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    Background: Like in several other Western countries, in the Dutch health care system regulated competition has been introduced. In order to make this work, comparable information is required about the performance of health care providers in terms of effectiveness, safety and patient experiences. Without further coordination, external actors will all try to force health care providers to be transparent. For health care providers this might result in a situation in which they have to deliver data for several sets of indicators, defined by different actors. Therefore, in the Netherlands an effort is made to define national sets of performance indicators and related measuring instruments. In this article, the following questions are addressed, using patient experiences as an example: - When and how are stakeholders involved in the development of indicators and instruments that measure the patients' experiences with health care providers? - Does this involvement lead to indicators and instruments that match stakeholders' information needs? Discussion: The Dutch experiences show that it is possible to implement national indicator sets and to reach consensus about what needs to be measured. Preliminary evaluations show that for health care providers and health insurers the benefits of standardization outweigh the possible loss of tailor-made information. However, it has also become clear that particular attention should be given to the participation of patient/consumer organisations. Summary: Stakeholder involvement is complex and time-consuming. However, it is the only way to balance the information needs of all the parties that ask for and benefit from transparency, without frustrating the health care system.
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