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
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
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 footprint. While the median PTF field has been imaged 40 times in \textit{R}-band,
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 -band observations, 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
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
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
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
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 and the velocity normal to the layers,
, 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
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.
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
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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