3,964 research outputs found

    Applications of Monte Carlo analysis to tungsten resonance absorption

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    Applications of Monte Carlo analysis to tungsten resonance absorptio

    How soon should serum potassium levels be monitored for patients started on diuretics?

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    Case series show that hypokalemia following initiation of diuretic therapy occurs in most patients within 2 to 8 weeks. However, no studies are available that adequately predict the risk of this complex and multifactorial condition. Patients taking diuretics should have a potassium level checked in the first 2 to 8 weeks after initiating therapy. Mild hypokalemia (3.1 to 3.4 mmol/L) may be transient, so a repeat measurement may be considered before initiating potassium replacement. Dietary sodium restriction may also help to conserve potassium, because this will decrease urinary flow rate and potassium loss. The frequency with which to check potassium levels should be guided by the patients' underlying clinical conditions and dietary potassium and sodium intake. (Grade of Recommendation: C, based on case series

    Small high-temperature nuclear reactors for space power

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    Criticality calculations for small, cylindrical, lithium cooled reactors for space power system

    How can I improve patient adherence to prescribed medication?

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    Two randomized clinical trials have shown that simplified dosing schedules have improved patient adherence to medication as prescribed. Some, but not all, randomized controlled trials show multidimensional interventions can also improve adherence. These interventions include combinations of patient and family education, home monitoring of disease status, and increased convenience of care, such as workplace access. (Grade of Recommendation: B, based on randomized controlled trials

    Політична економія глобалізму і проблеми структурної модернізації національної економіки

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    У статті досліджується політична економія глобалізму як транзитивної системи зі своїми протиріччями та внутрішніми конфліктами. Розкриваються негативні наслідки і ризики функціонування системи силового глобалізму та його відмінності від об’єктивної природної глобалізації як форми глобальної інтеграції. Увага також акцентується на ролі держави в сучасних глобалізаційних процесах та на проблемі структурної модернізації національної економіки в умовах глобальної конкурентності. Проаналізовано основні вектори і характер глобальних зрушень на початку ХХІ ст. та спрогнозовано їх тенденції до середини століття.В статье исследуется политическая экономия глобализма как транзитивной системы со своими противоречиями и внутренними конфликтами. Раскрываются негативные последствия и риски функционирования системы силового глобализма и его отличия от объективной естественной глобализации как формы глобальной интеграции. Внимание также акцентируется на роли государства в современных глобализационных процессах и на проблеме структурной модернизации национальной экономики в условиях глобальной конкурентности. Проанализированы основные векторы и характер глобальных сдвигов в начале ХХІ века и спрогнозированы их тенденции к середине века.In this article the political economy of globalism as a transitive system with its contradictions and internal conflicts is investigated. Negative consequences and risks of functioning of power globalism system and its differences from objective natural globalization as form of global integration are covered. Attention is also accented on the role of the state in modern globalization processes and on the problem of structural modernization of national economy in the global competition conditions. Basic vectors and character of global changes at the beginning of the XXIst century are analysed and their tendencies to the middle of age are predicted

    Heavy ion collisions: Correlations and Fluctuations in particle production

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    Correlations and fluctuations (the latter are directly related to the 2-particle correlations) is one of the important directions in analysis of heavy ion collisions. At the current stage of RHIC exploration, when the details matter, basically any physics question is addressed with help of correlation techniques. In this talk I start with a general introduction to the correlation and fluctuation formalism and discuss weak and strong sides of different type of observables. In more detail, I discuss the two-particle ptp_t correlations/\mpt fluctuations. In spite of not observing any dramatic changes in the event-by-event fluctuations with energy, which would indicate a possible phase transition, such correlations measurements remain an interesting and important subject, bringing valuable information. Lastly, I show how radial flow can generate characteristic azimuthal, transverse momentum and rapidity correlations, which could qualitatively explain many of recently observed phenomena in nuclear collisions.Comment: 8 pages, 8 figures. Invited talk at 5th International Conference on Physics and Astrophysics of Quark Gluon Plasma, February 8-12, 2005, Salt Lake City, Kolkata, Indi

    Recombination Ghosts in Littrow Configuration: Implications for Spectrographs Using Volume Phase Holographic Gratings

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    We report the discovery of optical ghosts generated when using Volume Phase Holographic (VPH) gratings in spectrographs employing the Littrow configuration. The ghost is caused by light reflected off the detector surface, recollimated by the camera, recombined by, and reflected from, the grating and reimaged by the camera onto the detector. This recombination can occur in two different ways. We observe this ghost in two spectrographs being developed by the University of Wisconsin - Madison: the Robert Stobie Spectrograph for the Southern African Large Telescope and the Bench Spectrograph for the WIYN 3.5m telescope. The typical ratio of the brightness of the ghost relative to the integrated flux of the spectrum is of order 10^-4, implying a recombination efficiency of the VPH gratings of order 10^-3 or higher, consistent with the output of rigorous coupled wave analysis. Any spectrograph employing VPH gratings, including grisms, in Littrow configuration will suffer from this ghost, though the general effect is not intrinsic to VPH gratings themselves and has been observed in systems with conventional gratings in non-Littrow configurations. We explain the geometric configurations that can result in the ghost as well as a more general prescription for predicting its position and brightness on the detector. We make recommendations for mitigating the ghost effects for spectrographs and gratings currently built. We further suggest design modifications for future VPH gratings to eliminate the problem entirely, including tilted fringes and/or prismatic substrates. We discuss the resultant implications on the spectrograph performance metrics.Comment: 13 pages, 8 figures, emulateapj style, accepted for publication in PAS

    Transport properties of isospin effective mass splitting

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    We investigate in detail the momentum dependence (MDMD) of the effective in medium Nucleon-Nucleon (NNNN) interaction in the isovector channel. We focus the discussion on transport properties of the expected neutron-proton (n/pn/p) effective mass splitting at high isospin density. We look at observable effects from collective flows in Heavy Ion Collisions (HICHIC) of charge asymmetric nuclei at intermediate energies. Using microscopic kinetic equation simulations nucleon transverse and elliptic collective flows in Au+AuAu+Au collisions are evaluated. In spite of the reduced charge asymmetry of the interacting system interesting isospinMDisospin-MD effects are revealed. Good observables, particularly sensitive to the n/pn/p-mass splitting, appear to be the differences between neutron and proton flows. The importance of more exclusive measurements, with a selection of different bins of the transverse momenta (ptp_t) of the emitted particles, is stressed. In more inclusive data a compensation can be expected from different ptp_t-contributions, due to the microscopic isospinMDisospin-MD structure of the nuclear mean field in asymmetric matter.Comment: 18 pages, 11 figure

    The Extended Shapes of Galactic Satellites

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    We are exploring the extended stellar distributions of Galactic satellite galaxies and globular clusters. For seven objects studied thus far, the observed profile departs from a King function at large r, revealing a ``break population'' of stars. In our sample, the relative density of the ``break'' correlates to the inferred M/L of these objects. We discuss opposing hypotheses for this trend: (1) Higher M/L objects harbor more extended dark matter halos that support secondary, bound, stellar ``halos''. (2) The extended populations around dwarf spheroidals (and some clusters) consist of unbound, extratidal debris from their parent objects, which are undergoing various degrees of tidal disruption. In this scenario, higher M/L ratios reflect higher degrees of virial non-equilibrium in the parent objects, thus invalidating a precept underlying the use of core radial velocities to obtain masses.Comment: 8 pages, including 2 figures Yale Cosmology Workshop: The Shapes of Galaxies and Their Halo

    Differential flow in heavy-ion collisions at balance energies

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    A strong differential transverse collective flow is predicted for the first time to occur in heavy-ion collisions at balance energies. We also give a novel explanation for the disappearance of the total transverse collective flow at the balance energies. It is further shown that the differential flow especially at high transverse momenta is a useful microscope capable of resolving the balance energy's dual sensitivity to both the nuclear equation of state and in-medium nucleon-nucleon cross sections in the reaction dynamics.Comment: Phys. Rev. Lett. (1999) in pres
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