806 research outputs found

    Spin relaxation in mesoscopic superconducting Al wires

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    We studied the diffusion and the relaxation of the polarized quasiparticle spins in superconductors. To that end, quasiparticles of polarized spins were injected through an interface of a mesoscopic superconducting Al wire in proximity contact with an overlaid ferromagnetic Co wire in the single-domain state. The superconductivity was observed to be suppressed near the spin-injecting interface, as evidenced by the occurrence of a finite voltage for a bias current below the onset of the superconducting transition. The spin diffusion length, estimated from finite voltages over a certain length of Al wire near the interface, was almost temperature independent in the temperature range sufficiently below the superconducting transition but grew as the transition temperature was approached. This temperature dependence suggests that the relaxation of the spin polarization in the superconducting state is governed by the condensation of quasiparticles to the paired state. The spin relaxation in the superconducting state turned out to be more effective than in the normal state.Comment: 9 pages, 8 figure

    Peripheral lymphocytosis in tropical splenomegaly syndrome

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    The Chemical Compositions of Very Metal-Poor Stars HD 122563 and HD 140283; A View From the Infrared

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    From high resolution (R = 45,000), high signal-to-noise (S/N > 400) spectra gathered with the Immersion Grating Infrared Spectrograph (IGRINS) in the H and K photometric bands, we have derived elemental abundances of two bright, well-known metal-poor halo stars: the red giant HD 122563 and the subgiant HD 140283. Since these stars have metallicities approaching [Fe/H] = -3, their absorption features are generally very weak. Neutral-species lines of Mg, Si, S and Ca are detectable, as well as those of the light odd-Z elements Na and Al. The derived IR-based abundances agree with those obtained from optical-wavelength spectra. For Mg and Si the abundances from the infrared transitions are improvements to those derived from shorter wavelength data. Many useful OH and CO lines can be detected in the IGRINS HD 122563 spectrum, from which derived O and C abundances are consistent to those obtained from the traditional [O I] and CH features. IGRINS high resolutions H- and K-band spectroscopy offers promising ways to determine more reliable abundances for additional metal-poor stars whose optical features are either not detectable, or too weak, or are based on lines with analytical difficulties.Comment: Accepted for publication in ApJ (28 pages, 4 tables, 6 figures

    Critical point network for drainage between rough surfaces

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    In this paper, we present a network method for computing two-phase flows between two rough surfaces with significant contact areas. Low-capillary number drainage is investigated here since one-phase flows have been previously investigated in other contributions. An invasion percolation algorithm is presented for modeling slow displacement of a wetting fluid by a non wetting one between two rough surfaces. Short-correlated Gaussian process is used to model random rough surfaces.The algorithm is based on a network description of the fracture aperture field. The network is constructed from the identification of critical points (saddles and maxima) of the aperture field. The invasion potential is determined from examining drainage process in a flat mini-channel. A direct comparison between numerical prediction and experimental visualizations on an identical geometry has been performed for one realization of an artificial fracture with a moderate fractional contact area of about 0.3. A good agreement is found between predictions and observations

    Motivations and Conflicts in Prison Medical Contracting

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    State correctional departments are responsible for all medical care incarcerated individuals require. Many systems outsource their medical State correctional departments are responsible for all medical care incarcerated individuals require. Many systems outsource their medical program. Literature indicates that many of these contracts experience significant issues that negatively impact state resources, including both personnel and money. This dissertation explores the relationship between prison administrators\u27 motivations and the structure, outcomes, efficiencies, and partner conflicts that arise in the contractual process. Using a framework developed from Incomplete Contract Theory, Contracts as Reference Points Theory and the concept of “essential tension,” this dissertation hypothesizes that the administrator’s motivation will impact the likelihood of success, contract efficiencies and partnership conflicts in case of prison medical contracts. The mixed-method study employs both quantitative and qualitative research methods. Study results indicate a preliminary finding that public administrators’ motivation does correlates with predictable differences in contract design and contract outcomes. States motivated to improve cost control, are more likely to allow the vendor space to manage financial resources but restrict the ability to determine efficient ways to achieve quality, which seems associated with problems in outputs, efficiencies and conflicts. These findings have implications for contracting and the use of contracts by public administrators. The results suggest that contract completeness is more nuanced than a contract being complete or not complete on the whole. Additionally, the application of completeness and incompleteness in different sections can be an intentional and strategic action on the part of the public administrator that could be used to enhance the usefulness of a complex contract. . Literature indicates that many of these contracts experience significant issues that negatively impact state resources, including both personnel and money. This dissertation explores the relationship between prison administrators\u27 motivations and the structure, outcomes, efficiencies, and partner conflicts that arise in the contractual process. Using a framework developed from Incomplete Contract Theory, Contracts as Reference Points Theory and the concept of “essential tension,” this dissertation hypothesizes that the administrator’s motivation will impact the likelihood of success, contract efficiencies and partnership conflicts in case of prison medical contracts. The mixed-method study employs both quantitative and qualitative research methods. Study results indicate a preliminary finding that public administrators’ motivation does correlates with predictable differences in contract design and contract outcomes. States motivated to improve cost control, are more likely to allow the vendor space to manage financial resources but restrict the ability to determine efficient ways to achieve quality, which seems associated with problems in outputs, efficiencies and conflicts. These findings have implications for contracting and the use of contracts by public administrators. The results suggest that contract completeness is more nuanced than a contract being complete or not complete on the whole. Additionally, the application of completeness and incompleteness in different sections can be an intentional and strategic action on the part of the public administrator that could be used to enhance the usefulness of a complex contract

    Approximate Ginzburg-Landau solution for the regular flux-line lattice. Circular cell method

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    A variational model is proposed to describe the magnetic properties of type-II superconductors in the entire field range between Hc1H_{c1} and Hc2H_{c2} for any values of the Ginzburg-Landau parameter κ>1/2\kappa>1/\sqrt{2}. The hexagonal unit cell of the triangular flux-line lattice is replaced by a circle of the same area, and the periodic solutions to the Ginzburg-Landau equations within this cell are approximated by rotationally symmetric solutions. The Ginzburg-Landau equations are solved by a trial function for the order parameter. The calculated spatial distributions of the order parameter and the magnetic field are compared with the corresponding distributions obtained by numerical solution of the Ginzburg-Landau equations. The comparison reveals good agreement with an accuracy of a few percent for all κ\kappa values exceeding κ1\kappa \approx 1. The model can be extended to anisotropic superconductors when the vortices are directed along one of the principal axes. The reversible magnetization curve is calculated and an analytical formula for the magnetization is proposed. At low fields, the theory reduces to the London approach at κ1\kappa \gg 1, provided that the exact value of Hc1H_{c1} is used. At high fields, our model reproduces the main features of the well-known Abrikosov theory. The magnetic field dependences of the reversible magnetization found numerically and by our variational method practically coincide. The model also refines the limits of some approximations which have been widely used. The calculated magnetization curves are in a good agreement with experimental data on high-Tc_c superconductors.Comment: 8 pages, RevTex, 6 figures, submitted to Phys. Rev.

    Mark correlations: relating physical properties to spatial distributions

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    Mark correlations provide a systematic approach to look at objects both distributed in space and bearing intrinsic information, for instance on physical properties. The interplay of the objects' properties (marks) with the spatial clustering is of vivid interest for many applications; are, e.g., galaxies with high luminosities more strongly clustered than dim ones? Do neighbored pores in a sandstone have similar sizes? How does the shape of impact craters on a planet depend on the geological surface properties? In this article, we give an introduction into the appropriate mathematical framework to deal with such questions, i.e. the theory of marked point processes. After having clarified the notion of segregation effects, we define universal test quantities applicable to realizations of a marked point processes. We show their power using concrete data sets in analyzing the luminosity-dependence of the galaxy clustering, the alignment of dark matter halos in gravitational NN-body simulations, the morphology- and diameter-dependence of the Martian crater distribution and the size correlations of pores in sandstone. In order to understand our data in more detail, we discuss the Boolean depletion model, the random field model and the Cox random field model. The first model describes depletion effects in the distribution of Martian craters and pores in sandstone, whereas the last one accounts at least qualitatively for the observed luminosity-dependence of the galaxy clustering.Comment: 35 pages, 12 figures. to be published in Lecture Notes of Physics, second Wuppertal conference "Spatial statistics and statistical physics

    Human H5N1 influenza infections in Cambodia 2005-2011: case series and cost-of-illness.

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    BACKGROUND: Southeast Asia has been identified as a potential epicentre of emerging diseases with pandemic capacity, including highly pathogenic influenza. Cambodia in particular has the potential for high rates of avoidable deaths from pandemic influenza due to large gaps in health system resources. This study seeks to better understand the course and cost-of-illness for cases of highly pathogenic avian influenza in Cambodia. METHODS: We studied the 18 laboratory-confirmed cases of avian influenza subtype H5N1 identified in Cambodia between January 2005 and August 2011. Medical records for all patients were reviewed to extract information on patient characteristics, travel to hospital, time to admission, diagnostic testing, treatment and disease outcomes. Further data related to costs was collected through interviews with key informants at district and provincial hospitals, the Ministry of Health and non-governmental organisations. An ingredient-based approach was used to estimate the total economic cost for each study patient. Costing was conducted from a societal perspective and included both financial and opportunity costs to the patient or carer. Sensitivity analysis was undertaken to evaluate potential change or variation in the cost-of-illness. RESULTS: Of the 18 patients studied, 11 (61%) were under the age of 18 years. The majority of patients (16, 89%) died, eight (44%) within 24 hours of hospital admission. There was an average delay of seven days between symptom onset and hospitalisation with patients travelling an average of 148 kilometres (8-476 km) to the admitting hospital. Five patients were treated with oseltamivir of whom two received the recommended dose. For the 16 patients who received all their treatment in Cambodia the average per patient cost of H5N1 influenza illness was US300ofwhich85.0300 of which 85.0% comprised direct medical provider costs, including diagnostic testing (41.2%), pharmaceuticals (28.4%), hospitalisation (10.4%), oxygen (4.4%) and outpatient consultations (0.6%). Patient or family costs were US45 per patient (15.0%) of total economic cost. CONCLUSION: Cases of avian influenza in Cambodia were characterised by delays in hospitalisation, deficiencies in some aspects of treatment and a high fatality rate. The costs associated with medical care, particularly diagnostic testing and pharmaceutical therapy, were major contributors to the relatively high cost-of-illness
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