1,505 research outputs found

    Path Dependence in Disability

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    The average prevalence of disability in most African countries is 10% but for many it exceeds the global disability prevalence rate of 15%. The extent to which this disability capturing functional and activity limitations results in permanent job loss, lowered lifetime income, and assets, in part, depends upon the extent to which the onset of limitations becomes permanent. In this paper we use five rounds of longitudinal data from rural Malawi, a low income African country with high prevalence of disability, to examine path dependence in activity limitations. We estimate a dynamic linear panel data model where the coefficient on the one-period lagged health outcome captures path dependence in limitations. Our preferred Arellano-Bover estimates show that males experience persistence in both the incidence and intensity of severe limitations but are able to recover from all other limitations, whereas, females exhibit no significant persistence on any type of limitations. Our findings have important policy implications for computing the long-term costs associated with onsets of activity limitations as these costs can be moderated by the recovery exhibited in these limitations

    Universality of quantum Brownian motion

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    Are Markovian master equations for quantum Brownian motion independent of model assumptions used in the derivation and, thus, universal? With the aim of answering this question, we use a random band-matrix model for the system-bath interaction to derive Markovian master equations for the time evolution of one-dimensional quantum systems weakly coupled to a heat bath. We study in detail two simple systems, the harmonic oscillator and the two-level system. Our results are in complete agreement with those of earlier models, like the Caldeira-Legget model and, in the large-band limit, with the Agarwal equations (both with and without rotating-wave approximation). This proves the universality of these master equations.Comment: 24 page

    A Global Kinetic Mechanism for the Prediction of Hg Oxidation by a Chlorine Species

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    This paper presents a global kinetic model developed from laboratory test results. The model consists of five global reactions - two reversible and three irreversible. The reaction constants for the Arrhenius expression formulation were determined from a set of 35 experiments involving a variety of flue gas compositions that include bulk gases (N2, CO2 and O2.) and trace gases (NO, SO2, Hg, Cl2); at a range of temperatures (from 540 °C to 166 °C) and a variety of residence times (between 2.7 and 3.3 seconds). The values obtained for the reaction constants were further used to predict experimental data from eleven published mercury data sources. The predicted values corresponded very well compared to the observed published data.Key words:  Kinetics model; Mercury emission; Homogeneous mercury oxidatio

    Biphasic Synovial Sarcoma of the Extremity: Quadruple Approach of Isolated Limb Perfusion, Surgical Ablation, Adipofascial Perforator Flap and Radiation to Avoid Amputation

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    Synovial sarcoma is a rare type of soft tissue sarcoma that occurs mostly in young adults, and it is always regarded as a high-grade tumor. Here, we report the case of a 31-year-old German Caucasian male with synovial sarcoma of the wrist who was offered amputation at his local hospital. After referral to our Reference Centre for Soft Tissue Sarcoma, the quadruple approach of isolated limb perfusion, surgical ablation, adipofascial perforator flap and radiation avoided amputation and enabled preservation of good hand function with no evidence of recurrence or metastasis after 1 year

    Multiple Cytochrome P450 Isozymes in Murine Skin: Induction of P450 1A, 2B, 2E, and 3A by Dexamethasone

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    Cytochrome P450s (P450s) are a supergene family of enzymes responsible for the metabolism of a wide range of endogenous and foreign compounds. P450 isozymes possess overlapping substrate specificity. Systemic administration of dexamethasone, a widely used topical agent in dermatologic practice, to animals is known to result in the induction of multiple P450 isozymes in liver. In this study the effect of topical application of dexamethasone to mice on P450-dependent monooxygenase activities, expression of P450 isozymes, and P450 mRNA levels in skin was assessed. The treatment of mice with dexamethasone resulted in significant induction of 7-ethoxyresorufin O-deethylase (2.3 times), 7-pentoxyresorufin O-depentylase (19.2 times), para-nitrophenol hydroxylase (7.5 times), and erythromycin N-demethylase (2.2 times) activities; the monooxygenases catalyzed preferentially by P450 isozymes 1A1, 2B1, 2E1, and 3A, respectively. Immunoblot analysis of cutaneous microsomes, employing antibodies directed against purified P450s 1A1/2, 2B1/2, 2E1, and 3A, showed that dexamethasone treatment results in an increased immunoreactivity (1.8 – 13.9 times). In immunohistochemical staining of skin with antibody against P4502B1/2, topical application of dexamethasone resulted in an increased reactivity towards microsomal protein in the suprabasal layer of the epidermis and with the cells of the hair follicles. Whereas constitutive expression of mRNAs for CYP1A1 and CYP2E1 was evident in murine skin, any change in the levels of these mRNAs following treatment with dexamethasone was not apparent. The results of our study indicate that the application of dexamethasone to murine skin results in the induction of several families of P450 isozymes, suggesting that murine skin contains multiple inducible P450 isozymes capable of participating in the metabolism of a wide range of xenobiotics and endogenous compounds

    Polarization Squeezing of Continuous Variable Stokes Parameters

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    We report the first direct experimental characterization of continuous variable quantum Stokes parameters. We generate a continuous wave light beam with more than 3 dB of simultaneous squeezing in three of the four Stokes parameters. The polarization squeezed beam is produced by mixing two quadrature squeezed beams on a polarizing beam splitter. Depending on the squeezed quadrature of these two beams the quantum uncertainty volume on the Poincar\'{e} sphere became a `cigar' or `pancake'-like ellipsoid.Comment: 4 pages, 5 figure

    Oxy-Combustion Boiler Material Development

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    Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO2 level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year) data. The test program details and data are presented herein
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