7,520 research outputs found

    Diabetes in Sub Saharan Africa 1999-2011: Epidemiology and Public Health Implications. A Systematic Review.

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    Diabetes prevalence is increasing globally, and Sub-Saharan Africa is no exception. With diverse health challenges, health authorities in Sub-Saharan Africa and international donors need robust data on the epidemiology and impact of diabetes in order to plan and prioritise their health programmes. This paper aims to provide a comprehensive and up-to-date review of the epidemiological trends and public health implications of diabetes in Sub-Saharan Africa. We conducted a systematic literature review of papers published on diabetes in Sub-Saharan Africa 1999-March 2011, providing data on diabetes prevalence, outcomes (chronic complications, infections, and mortality), access to diagnosis and care and economic impact. Type 2 diabetes accounts for well over 90% of diabetes in Sub-Saharan Africa, and population prevalence proportions ranged from 1% in rural Uganda to 12% in urban Kenya. Reported type 1 diabetes prevalence was low and ranged from 4 per 100,000 in Mozambique to 12 per 100,000 in Zambia. Gestational diabetes prevalence varied from 0% in Tanzania to 9% in Ethiopia. Proportions of patients with diabetic complications ranged from 7-63% for retinopathy, 27-66% for neuropathy, and 10-83% for microalbuminuria. Diabetes is likely to increase the risk of several important infections in the region, including tuberculosis, pneumonia and sepsis. Meanwhile, antiviral treatment for HIV increases the risk of obesity and insulin resistance. Five-year mortality proportions of patients with diabetes varied from 4-57%. Screening studies identified high proportions (> 40%) with previously undiagnosed diabetes, and low levels of adequate glucose control among previously diagnosed diabetics. Barriers to accessing diagnosis and treatment included a lack of diagnostic tools and glucose monitoring equipment and high cost of diabetes treatment. The total annual cost of diabetes in the region was estimated at US67.03billion,orUS67.03 billion, or US8836 per diabetic patient. Diabetes exerts a significant burden in the region, and this is expected to increase. Many diabetic patients face significant challenges accessing diagnosis and treatment, which contributes to the high mortality and prevalence of complications observed. The significant interactions between diabetes and important infectious diseases highlight the need and opportunity for health planners to develop integrated responses to communicable and non-communicable diseases

    INITIAL APPLICATIONS OF FUZZY SET PROCEDURES FOR ESTIMATION OF EXPORT BASE EMPLOYMENT

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    Current export base methods that calculate basic and non-basic employment are too restrictive because they fail to account for uncertainty involved in the process. This paper shows the assignment of industries as either basic or non-basic by the location quotient procedure does not consistently represent the data for Nevada counties. Using fuzzy set procedures and membership functions in conjunction with the location quotient allow more flexibility in terms of matching the data for each industry in the region of interest. Using fuzzy set procedures we determine the proportion of employment that is basic and non-basic in nine non-governmental industries.Labor and Human Capital,

    Ion observations from geosynchronous orbit as a proxy for ion cyclotron wave growth during storm times

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    [1] There is still much to be understood about the processes contributing to relativistic electron enhancements and losses in the radiation belts. Wave particle interactions with both whistler and electromagnetic ion cyclotron (EMIC) waves may precipitate or accelerate these electrons. This study examines the relation between EMIC waves and resulting relativistic electron flux levels after geomagnetic storms. A proxy for enhanced EMIC waves is developed using Los Alamos National Laboratory Magnetospheric Plasma Analyzer plasma data from geosynchronous orbit in conjunction with linear theory. In a statistical study using superposed epoch analysis, it is found that for storms resulting in net relativistic electron losses, there is a greater occurrence of enhanced EMIC waves. This is consistent with the hypothesis that EMIC waves are a primary mechanism for the scattering of relativistic electrons and thus cause losses of such particles from the magnetosphere

    Systematic study of Optical Feshbach Resonances in an ideal gas

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    Using a narrow intercombination line in alkaline earth atoms to mitigate large inelastic losses, we explore the Optical Feshbach Resonance (OFR) effect in an ultracold gas of bosonic 88^{88}Sr. A systematic measurement of three resonances allows precise determinations of the OFR strength and scaling law, in agreement with coupled-channels theory. Resonant enhancement of the complex scattering length leads to thermalization mediated by elastic and inelastic collisions in an otherwise ideal gas. OFR could be used to control atomic interactions with high spatial and temporal resolution.Comment: Significant changes to text and figure presentation to improve clarity. Extended supplementary material. 4 pages, 4 figures; includes supplementary material 8 pages, 4 figures. Submitted to Physical Review Letter

    The phonon dispersion of graphite by inelastic x-ray scattering

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    We present the full in-plane phonon dispersion of graphite obtained from inelastic x-ray scattering, including the optical and acoustic branches, as well as the mid-frequency range between the KK and MM points in the Brillouin zone, where experimental data have been unavailable so far. The existence of a Kohn anomaly at the KK point is further supported. We fit a fifth-nearest neighbour force-constants model to the experimental data, making improved force-constants calculations of the phonon dispersion in both graphite and carbon nanotubes available.Comment: 7 pages; submitted to Phys. Rev.

    The Biotite to Phengite Reaction and Mica-dominated Melting in Fluid + Carbonate-saturated Pelites at High Pressures

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    Subsolidus and melting experiments were performed at 2·0-3·7 GPa and 750-1300°C on a carbonated pelite in the model system K2O-CaO-MgO-Al2O3-SiO2-H2O-CO2 to define stabilities of potassic micas and fluid-present melting reactions. The biotite to phengite reaction occurs at pressures between 2· 4 and 2·6 GPa for temperatures of 750-850°C, and the amphibole to clinopyroxene reaction from 2·0 GPa, 875°C to 2·5 GPa, 740°C. Dolomite is the carbonate phase stable at subsolidus conditions. The biotite to phengite reaction preserves K2O, but is not H2O conservative, as a fluid is produced from the decomposition of zoisite. Phengite + quartz control fluid-saturated melting at a pressure (P) >2·6 GPa, whereas biotite + quartz dominate at P <2· 4 GPa. Incongruent melting occurs through the reactions phengite or biotite + zoisite + quartz/coesite + fluid = silicate melt + clinopyroxene + kyanite. Overstepping of the solidus, located at 850-950°C, results in 7-24 wt % metaluminous K-rich granitic melts. The experiments define the melting surface of the model system, projected from kyanite + quartz/coesite + fluid onto the K2O-CaO-MgO plane. The solidus melts in the studied system occur at a peritectic point consuming mica + zoisite and forming clinopyroxene. With increasing temperature (T), carbonated pelites then evolve along a peritectic curve along which further clinopyroxene is produced until zoisite is exhausted. This is then followed by a peritectic curve consuming clinopyroxene and producing garnet. A comparison of CO2-bearing with CO2-free experiments from the literature suggests that the main effect of adding calcite to a continental sediment is not the minor shift of typically 20-30°C of reactions involving fluid, but the change in bulk Ca/(Mg + Fe) ratio stabilizing calcic phases at the expense of ferromagnesian phases. The experiments suggest that in most subduction zones, CO2, H2O and K2O will be carried to depths in excess of 120-150 km through carbonates and K-micas, as partial melting occurs only at temperatures at the uppermost end of thermal models of subduction zones. Nevertheless, the release of fluid through P-induced decomposition of amphibole and zoisite provides some H2O for arc magma formation. Melting at higher temperatures (e.g. resulting from slower burial rates or from incorporation of subducted crust into the mantle) will produce potassic granitic melts and provide a substantial volatile and K source for the formation of arc magma

    Extreme non-linear response of ultra-narrow optical transitions in cavity QED for laser stabilization

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    We explore the potential of direct spectroscopy of ultra-narrow optical transitions of atoms localized in an optical cavity. In contrast to stabilization against a reference cavity, which is the approach currently used for the most highly stabilized lasers, stabilization against an atomic transition does not suffer from Brownian thermal noise. Spectroscopy of ultra-narrow optical transitions in a cavity operates in a very highly saturated regime in which non-linear effects such as bistability play an important role. From the universal behavior of the Jaynes-Cummings model with dissipation, we derive the fundamental limits for laser stabilization using direct spectroscopy of ultra-narrow atomic lines. We find that with current lattice clock experiments, laser linewidths of about 1 mHz can be achieved in principle, and the ultimate limitations of this technique are at the 1 μ\mu Hz level.Comment: 5 pages, 4 figure

    Raman modes of the deformed single-wall carbon nanotubes

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    With the empirical bond polarizability model, the nonresonant Raman spectra of the chiral and achiral single-wall carbon nanotubes (SWCNTs) under uniaxial and torsional strains have been systematically studied by \textit{ab initio} method. It is found that both the frequencies and the intensities of the low-frequency Raman active modes almost do not change in the deformed nanotubes, while their high-frequency part shifts obviously. Especially, the high-frequency part shifts linearly with the uniaxial tensile strain, and two kinds of different shift slopes are found for any kind of SWCNTs. More interestingly, new Raman peaks are found in the nonresonant Raman spectra under torsional strain, which are explained by a) the symmetry breaking and b) the effect of bond rotation and the anisotropy of the polarizability induced by bond stretching
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