3,494 research outputs found

    The Effects of Medicaid Reimbursement Rates on Access to Dental Care

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    Compares efforts to improve Medicaid access to dental care in California with those in Alabama, Michigan, South Carolina, Tennessee, Virginia, and Washington, and assesses the extent to which raising dentists' Medicaid reimbursement rates improved access

    Electroconvulsive therapy in geriatric patients: A literature review and program report from Virginia Commonwealth University, Richmond, Virginia, USA

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    Electroconvulsive therapy (ECT) is an effective therapeutic intervention in the elderly patients with major depression, especially those with psychosis, suicidality, catatonia, nutritional compromise, and resistance to medications. Response rates can be as high as 80%. We present an extensive review of the relevant literature, provide a description of the ECT program at Virginia Commonwealth University in Richmond, Virginia, USA, and present results of our experience with ECT in fifty elderly patients. The treatments were safe, well tolerated, and produced high response rates, variably between 68% and 84%. Patients in the long‑term maintenance ECT program continue to show sustained benefits from ECT

    Lanthanum Telluride: Mechanochemical Synthesis of a Refractory Thermoelectric Material

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    Recent experimental work on lanthanum telluride has confirmed its significant potential as an n-type material for high temperature thermoelectric (TE) power generation application. The phase of interest, La3−xTe4, has a Th3P4 defect structure where x is the lanthanum vacancy with values ranging between 0 and 1/3. Thermoelectric properties change rapidly with x since the carrier concentration, n, is proportional to the (1−3x) parameter. Controlling the Te to La stoichiometry in lanthanum telluride is thus vital to achieving the optimum self-doping level for the highest dimensionless figure of merit ZT value. We report on a significant improvement in reproducibly preparing this refractory compound over prior lengthy and unwieldy high temperature experimental techniques developed in the 1980's. Mechanochemical processes are utilized to synthesize precise stoichiometries of lanthanum telluride at room temperature, enabling improved characterization, analysis and modeling of its transport properties as a function of the number of La vacancies. We report TE properties for a large range of the allowed compositions, with ZT values greater than 1.0 obtained at 1275 K for several compositions. In addition to stoichiometric optimization within the pure compound, chemical substitutions can enhance performance by decreasing the lattice thermal conductivity and tuning the electrical properties for maximum ZT values at lower temperatures; preliminary studies indicate that the addition of ytterbium increases ZT. Some properties pertaining to device development are discussed. Specifically, lanthanum telluride has a low sublimation rate, and a coefficient of thermal expansion that closely matches a p-type rare earth compound analog (the Yb14MnSb11 Zintl compound)

    Activist Inversions in Rio de Janeiro's Street Carnival during the COVID-19 Pandemic

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    UIDB/00472/2020 UIDP/00472/2020The carnival of 2021 of Rio de Janeiro was unprecedently cancelled due to the COVID-19 pandemic, and the city administration knew it would have to enforce the decision and convince residents to avoid celebrating despite the restrictions. Importantly, officials had the support of the samba schools and the blocos of street carnival, and the blocos organized a manifesto and campaign declaring that in 2021 carnival would be “at home.” While many scholars have shown how street music can mobilize revelers, this article shows that the blocos of Rio’s street carnival also have the capacity to demobilize them. Their campaign drew on familiar carnivalesque and Brazilian tropes to rationalize a biopolitical message of civic responsibility, respect for life, and resistance to virus denialism. They played on long-standing Brazilian tropes of carnival as an ephemeral moment whose presence is fleeting and soon experienced as saudade, or nostalgia. I explore various manifestations of the campaign, including its manifestos and arguments, as well as some of the alternatives that were offered, such as virtual carnival performances and new carnival songs adapted to the situation. By inverting their traditional demands to occupy the streets and instead limiting festivity to domestic space, the blocos framed their plea not as a departure from carnival tradition, but as fundamentally carnivalesque. I argue that classic carnival theories are best understood as performative rather than an explanatory; that is, it is how carnival practitioners deploy the carnivalesque tropes of inversion as elements of a persuasive discourse that is my focus.publishersversionpublishe

    Using Data to Drive State Improvement in Enrollment and Retention Performance

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    Outlines the RWJF Maximizing Enrollment program's core performance measures for Medicaid and Children's Health Insurance Program enrollment and retention, designed to assess state efforts to better utilize data to monitor and improve outreach and policy

    Zintl Chemistry for Designing High Efficiency Thermoelectric Materials

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    Zintl phases and related compounds are promising thermoelectric materials; for instance, high zT has been found in Yb_(14)MnSb_(11), clathrates, and the filled skutterudites. The rich solid-state chemistry of Zintl phases enables numerous possibilities for chemical substitutions and structural modifications that allow the fundamental transport parameters (carrier concentration, mobility, effective mass, and lattice thermal conductivity) to be modified for improved thermoelectric performance. For example, free carrier concentration is determined by the valence imbalance using Zintl chemistry, thereby enabling the rational optimization of zT. The low thermal conductivity values obtained in Zintl thermoelectrics arise from a diverse range of sources, including point defect scattering and the low velocity of optical phonon modes. Despite their complex structures and chemistry, the transport properties of many modern thermoelectrics can be understood using traditional models for heavily doped semiconductors

    Optimizing Thermoelectric Efficiency in La_(3−x)Te_4 via Yb Substitution

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    A low temperature, solid state synthesis technique has enabled the production of homogeneous samples of La_(3−x−y)Yb_yTe_4. This allows the substitution of divalent Yb to be utilized to optimize the thermoelectric performance in lanthanum telluride. The addition of Yb^(2+) changes the electrical transport properties in a manner that can be well understood using valence counting rules and a corresponding change in the Fermi energy. The substitution of Yb^(2+) for La^(3+) results in a threefold finer control over the carrier density n, thus allowing the optimum n ~ 0.3 × 10^(21) cm^(−3) to be both predicted and prepared. The net result is an improvement in thermoelectric efficiency, with zT reaching ~ 1.2 at 1273 K

    Transport properties of the layered Zintl compound SrZnSb_2

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    Transport properties of the layered Zintl compound SrZnSb_2 have been characterized from room temperature to 725 K on polycrystalline samples. SrZnSb_2 samples were found to be p-type with a Hall carrier concentration of 5×10^(20) cm^(−3) at room temperature, and a small Seebeck coefficient and electrical resistivity are observed. A single band model predicts that, even with optimal doping, significant thermoelectric performance will not be achieved in SrZnSb_2. A relatively low lattice thermal conductivity is observed, Îș_L~1.2 W m^(−1) K^(−1), at room temperature. The thermal transport of SrZnSb_2 is compared to that of the layered Zintl compounds AZn2Sb_2 (A=Ca,Yb,Sr,Eu), which have smaller unit cells and larger lattice thermal conductivity, Îș_L~2 W m^(−1) K^(−1), at 300K. Ultrasonic measurements, in combination with kinetic theory and the estimated Îș_L values, suggest that the lower Îș_L of SrZnSb_2 is primarily the result of a reduction in the volumetric specific heat of the acoustic phonons due to the increased number of atoms per unit cell. Therefore, this work recommends that unit cell size should be considered when selecting Zintl compounds for potential thermoelectric application
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