3,461 research outputs found

    The Impact of Antihypertensive Drugs on the Number and Risk of Death, Stroke and Myocardial Infarction in the United States

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    Estimating the value of medical innovation is a continual challenge. In this research, we quantify the impact of antihypertensive therapy on U.S. blood pressures, risk and number of heart attacks, strokes, and deaths. We also consider the potential for further improvements. We estimate the value of innovation using equations relating blood pressure to adverse outcomes from the Framingham Heart Study. Our results show that without antihypertensive therapy, 1999-2000 average blood pressure for the U.S. population age 40 plus would have been 10-13 percent higher. 86,000 excess premature deaths from cardiovascular disease (2001), and 833,000 hospital discharges for stroke and heart attacks (2002) would have occurred. Life expectancy would be 0.5 (men) and 0.4 (women) years lower. At guideline care, there would have been 89,000 fewer premature deaths (2001) and 420,000 fewer hospital discharges for stroke and heart attack (2002) than observed. Our analysis suggests that antihypertensive therapy has had a significant impact on cardiovascular health outcomes but that mortality gains would have been approximately twice as high if guideline care had been achieved for all.

    Statistical Searches for Microlensing Events in Large, Non-Uniformly Sampled Time-Domain Surveys: A Test Using Palomar Transient Factory Data

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    Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its \sim20,000deg220,000 \mathrm{deg}^2 footprint. While the median 7.26deg27.26 \mathrm{deg}^2 PTF field has been imaged \sim40 times in \textit{R}-band, \sim2300deg22300 \mathrm{deg}^2 have been observed >>100 times. We use PTF data to study the trade-off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a selection method using this statistic and apply it to data from fields with >>10 RR-band observations, 1.1×1091.1\times10^9 light curves, uncovering three candidate microlensing events. We lack simultaneous, multi-color photometry to confirm these as microlensing events. However, their number is consistent with predictions for the event rate in the PTF footprint over the survey's three years of operations, as estimated from near-field microlensing models. This work can help constrain all-sky event rate predictions and tests microlensing signal recovery in large data sets, which will be useful to future time-domain surveys, such as that planned with the Large Synoptic Survey Telescope.Comment: 13 pages, 14 figures; accepted for publication in ApJ. fixed author lis

    Coupling between Smectic and Twist Modes in Polymer Intercalated Smectics

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    We analyse the elastic energy of an intercalated smectic where orientationally ordered polymers with an average orientation varying from layer to layer are intercalated between smectic planes. The lowest order terms in the coupling between polymer director and smectic layer curvature are added to the smectic elastic energy. Integration over the smectic degrees of freedom leaves an effective polymer twist energy that has to be included into the total polymer elastic energy leading to a fluctuational renormalization of the intercalated polymer twist modulus. If the polymers are chiral this in its turn leads to a renormalization of the cholesteric pitch.Comment: 8 pages, 1 fig in ps available from [email protected] Replaced version also contains title and abstract in the main tex

    Effective Area-Elasticity and Tension of Micro-manipulated Membranes

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    We evaluate the effective Hamiltonian governing, at the optically resolved scale, the elastic properties of micro-manipulated membranes. We identify floppy, entropic-tense and stretched-tense regimes, representing different behaviors of the effective area-elasticity of the membrane. The corresponding effective tension depends on the microscopic parameters (total area, bending rigidity) and on the optically visible area, which is controlled by the imposed external constraints. We successfully compare our predictions with recent data on micropipette experiments.Comment: To be published in Phys. Rev. Let

    Assignment of the Human and Mouse Prion Protein Genes to Homologous Chromosomes

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    Purified preparations of scrapie prions contain one major macromolecule, designated prion protein (PrP). Genes encoding PrP are found in normal animals and humans but not within the infectious particles. The PrP gene was assigned to human chromosome 20 and the corresponding mouse chromosome 2 using somatic cell hybrids. In situ hybridization studies mapped the human PrP gene to band 20p12→pter. Our results should lead to studies of genetic loci syntenic with the PrP gene, which may play a role in the pathogenesis of prion diseases or other degenerative neurologic disorders

    Layer dynamics of a freely standing smectic-A film

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    We study the hydrodynamics of a freely-standing smectic-A film in the isothermal, incompressible limit theoretically by analyzing the linearized hydrodynamic equations of motion with proper boundary conditions. The dynamic properties for the system can be obtained from the response functions for the free surfaces. Permeation is included and its importance near the free surfaces is discussed. The hydrodynamic mode structure for the dynamics of the system is compared with that of bulk systems. We show that to describe the dynamic correlation functions for the system, in general, it is necessary to consider the smectic layer displacement uu and the velocity normal to the layers, vzv_z, together. Finally, our analysis also provides a basis for the theoretical study of the off-equilibrium dynamics of freely-standing smectic-A films.Comment: 22 pages, 4 figure

    Mixed pairing symmetry in \kappa-(BEDT-TTF)_2 X organic superconductors from ultrasonic velocity measurements

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    Discontinuities in elastic constants are detected at the superconducting transition of layered organic conductors \kappa-(BEDT-TTF)_{2}X by longitudinal and transverse ultrasonic velocity measurements. Symmetry arguments show that discontinuities in shear elastic constants can be explained in the orthorhombic compound only if the superconducting order parameter has a mixed character that can be of two types, either A_{1g}+B_{1g} or B_{2g}+B_{3g} in the classification of irreducible representations of the orthorhombic point group D_{2h}. Consistency with other measurements suggests that the A_{1g}+B_{1g} (d_{xy}+d_{z(x+y)}) possibility is realized. Such clear symmetry-imposed signatures of mixed order parameters have not been observed in other superconducting compounds.Comment: 5 pages, LaTeX,3 figure

    Mutation to ispA Produces Stable Small-Colony Variants of Pseudomonas aeruginosa That Have Enhanced Aminoglycoside Resistance.

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    Pseudomonas aeruginosa is a major pathogen in burn wound infections. We present one of the first reports of small-colony variant (SCV) emergence of P. aeruginosa, taken from a patient under aminoglycosides for a persistent burn wound infection. We confirm the causative role of a single ispA mutation in SCV emergence and increased aminoglycoside resistance. IspA is involved in the synthesis of ubiquinone, providing a possible link between electron transport and SCV formation in P. aeruginosa

    Magnetic Field Dependence of Electronic Specific Heat in Pr_{1.85} Ce_{0.15} CuO_4

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    The specific heat of electron-doped Pr_{1.85} Ce_{0.15} CuO_4 single crystals is reported for the temperature range 2 - 10 K and magnetic field range 0 - 10 T. A non-linear magnetic field dependence is observed for the field range 0 - 2 T. Our data supports a model with lines of nodes in the gap function of these superconductors. Theoretical calculations of the electronic specific heat for dirty d-wave, clean d-wave, and s-wave symmetries are compared to our data.Comment: 10 pages Latex and 4 eps figures, submitted to Phys. Rev.
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