4,860 research outputs found

    A scalable optical detection scheme for matter wave interferometry

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    Imaging of surface adsorbed molecules is investigated as a novel detection method for matter wave interferometry with fluorescent particles. Mechanically magnified fluorescence imaging turns out to be an excellent tool for recording quantum interference patterns. It has a good sensitivity and yields patterns of high visibility. The spatial resolution of this technique is only determined by the Talbot gratings and can exceed the optical resolution limit by an order of magnitude. A unique advantage of this approach is its scalability: for certain classes of nano-sized objects, the detection sensitivity will even increase significantly with increasing size of the particle.Comment: 10 pages, 4 figure

    Improving Health Care Quality through Value-Based Purchasing: What Can the Pioneers Teach Us?

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    The Department of Health Policy of Jefferson Medical College has been engaged in research on value-based purchasing (VBP) for the past five years. With support from The Commonwealth Fund, the Department’s research team has examined the potential of VBP to improve quality and cost-effectiveness of health care. This article summarizes this work

    Observation of slow light in the noise spectrum of a vertical external cavity surface emitting laser

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    The role of coherent population oscillations is evidenced in the noise spectrum of an ultra-low noise lasers. This effect is isolated in the intensity noise spectrum of an optimized single-frequency vertical external cavity surface emitting laser. The coherent population oscillations induced by the lasing mode manifest themselves through their associated dispersion that leads to slow light effects probed by the spontaneous emission present in the non-lasing side modes.Comment: accepted for publication in Phys. Rev. Let

    Asthma management programs in managed care organizations

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    The aim of this work was to investigate how managed care organizations (MCOs) currently approach asthma treatment and management and to determine factors affecting asthma outcomes. A Web-based survey was administered to a national sample of 351 medical directors of MCOs to investigate the asthma management program components in their organizations as well as gaps and barriers in the management of patients with asthma. All 134 (38.2%) responding medical directors reported that their organizations monitor asthma patients. Plans use a variety of asthma management activities, including general member education (90%), member education by mail (87%), self-management education (85%), and provider education (82%). Educational resources (89%) and telephone advice nurse (77%) were the most common self-management strategies offered. Among factors impeding the provision of effective asthma care, noncompliance with asthma treatment, the inappropriate use of medications, and the need for multiple medications were cited by virtually all respondents. Health plans rely on an array of strategies to manage asthma patients. Education encouraging patient self-management is a key component of asthma management programs. However, a considerable number of treatment approach barriers are impeding the achievement of proper asthma care. Without innovative approaches to care, it appears that current MCOs’ asthma management efforts may not result in substantial improvements in asthma outcomes

    Inter- and Intragranular Effects in Superconducting Compacted Platinum Powders

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    Compacted platinum powders exhibit a sharp onset of diamagnetic screening at T1.9T \simeq 1.9 mK in zero magnetic field in all samples investigated. This sharp onset is interpreted in terms of the intragranular transition into the superconducting state. At lower temperatures, the magnetic ac susceptibility strongly depends on the ac field amplitude and reflects the small intergranular critical current density jcj_{c}. This critical current density shows a strong dependence on the packing fraction f of the granular samples. Surprisingly, jcj_{c} increases significantly with decreasing f (jc(B=0,T=0)0.07j_{c}(B=0, T=0) \simeq 0.07 A/cm2^{2} for f = 0.67 and jc(B=0,T=0)0.8j_{c}(B=0, T=0) \simeq 0.8 A/cm2^{2} for f = 0.50). The temperature dependence of jcj_{c} shows strong positive curvature over a wide temperature range for both samples. The phase diagrams of inter- and intragranular superconductivity for different samples indicate that the granular structure might play the key role for an understanding of the origin of superconductivity in the platinum compacts.Comment: 11 pages including 9 figures. To appear in Phys. Rev. B in Nov. 0

    On positive occur-checks in unification

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    Toward a global description of the nucleus-nucleus interaction

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    Extensive systematization of theoretical and experimental nuclear densities and of optical potential strengths exctracted from heavy-ion elastic scattering data analyses at low and intermediate energies are presented.The energy-dependence of the nuclear potential is accounted for within a model based on the nonlocal nature of the interaction.The systematics indicate that the heavy-ion nuclear potential can be described in a simple global way through a double-folding shape,which basically depends only on the density of nucleons of the partners in the collision.The poissibility of extracting information about the nucleon-nucleon interaction from the heavy-ion potential is investigated.Comment: 12 pages,12 figure

    Factors predicting treatment of World Trade Center-related lung injury : a longitudinal cohort study

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    The factors that predict treatment of lung injury in occupational cohorts are poorly defined. We aimed to identify patient characteristics associated with initiation of treatment with inhaled corticosteroid/long-acting beta-agonist (ICS/LABA) >2 years among World Trade Center (WTC)-exposed firefighters. The study population included 8530 WTC-exposed firefighters. Multivariable logistic regression assessed the association of patient characteristics with ICS/LABA treatment for >2 years over two-year intervals from 11 September 2001-10 September 2017. Cox proportional hazards models measured the association of high probability of ICS/LABA initiation with actual ICS/LABA initiation in subsequent intervals. Between 11 September 2001-1 July 2018, 1629/8530 (19.1%) firefighters initiated ICS/LABA treatment for >2 years. Forced Expiratory Volume in 1 s (FEV1), wheeze, and dyspnea were consistently and independently associated with ICS/LABA treatment. High-intensity WTC exposure was associated with ICS/LABA between 11 September 2001-10 September 2003. The 10th percentile of risk for ICS/LABA between 11 September 2005-10 Septmeber 2007 was associated with a 3.32-fold increased hazard of actual ICS/LABA initiation in the subsequent 4 years. In firefighters with WTC exposure, FEV1, wheeze, and dyspnea were independently associated with prolonged ICS/LABA treatment. A high risk for treatment was identifiable from routine monitoring exam results years before treatment initiation

    Study of coupling loss on bi-columnar BSCCO/Ag tapes by a.c. susceptibility measurements

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    Coupling losses were studied in composite tapes containing superconducting material in the form of two separate stacks of densely packed filaments embedded in a metallic matrix of Ag or Ag alloy. This kind of sample geometry is quite favorable for studying the coupling currents and in particular the role of superconducting bridges between filaments. By using a.c. susceptibility technique, the electromagnetic losses as function of a.c. magnetic field amplitude and frequency were measured at the temperature T = 77 K for two tapes with different matrix composition. The length of samples was varied by subsequent cutting in order to investigate its influence on the dynamics of magnetic flux penetration. The geometrical factor χ0\chi_0 which takes into account the demagnetizing effects was established from a.c. susceptibility data at low amplitudes. Losses vs frequency dependencies have been found to agree nicely with the theoretical model developed for round multifilamentary wires. Applying this model, the effective resistivity of the matrix was determined for each tape, by using only measured quantities. For the tape with pure silver matrix its value was found to be larger than what predicted by the theory for given metal resistivity and filamentary architecture. On the contrary, in the sample with a Ag/Mg alloy matrix, an effective resistivity much lower than expected was determined. We explain these discrepancies by taking into account the properties of the electrical contact of the interface between the superconducting filaments and the normal matrix. In the case of soft matrix of pure Ag, this is of poor quality, while the properties of alloy matrix seem to provoke an extensive creation of intergrowths which can be actually observed in this kind of samples.Comment: 20 pages 11 figure, submitted to Superconductor Science and Technolog
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