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Strategies for Primary Prevention of Coronary Heart Disease Based on Risk Stratification by the ACC/AHA Lipid Guidelines, ATP III Guidelines, Coronary Calcium Scoring...
Background: Several approaches have been proposed for risk-stratification and primary prevention of coronary heart disease (CHD), but their comparative and cost-effectiveness is unknown. Methods: We constructed a state-transition microsimulation model to compare multiple approaches to the primary prevention of CHD in a simulated cohort of men aged 45–75 and women 55–75. Risk-stratification strategies included the 2013 American College of Cardiology/American Heart Association (ACC/AHA) guidelines on the treatment of blood cholesterol, the Adult Treatment Panel (ATP) III guidelines, and approaches based on coronary artery calcium (CAC) scoring and C-reactive protein (CRP). Additionally we assessed a treat-all strategy in which all individuals were prescribed either moderate-dose or high-dose statins and all males received low-dose aspirin. Outcome measures included CHD events, costs, medication-related side effects, radiation-attributable cancers, and quality-adjusted-life-years (QALYs) over a 30-year timeframe. Results: Treat-all with high-dose statins dominated all other strategies for both men and women, gaining 15.7 million QALYs, preventing 7.3 million myocardial infarctions, and saving over $238 billion, compared to the status quo, far outweighing its associated adverse events including bleeding, hepatitis, myopathy, and new-onset diabetes. ACC/AHA guidelines were more cost-effective than ATP III guidelines for both men and women despite placing 8.7 million more people on statins. For women at low CHD risk, treat-all with high-dose statins was more likely to cause a statin-related adverse event than to prevent a CHD event. Conclusions: Despite leading to a greater proportion of the population placed on statin therapy, the ACC/AHA guidelines are more cost-effective than ATP III. Even so, at generic prices, treating all men and women with statins and all men with low-dose aspirin appears to be more cost-effective than all risk-stratification approaches for the primary prevention of CHD. Especially for low-CHD risk women, decisions on the appropriate primary prevention strategy should be based on shared decision making between patients and healthcare providers
The measurements of light high-energy ions in NINA-2 experiment
The flux of energetic light ions at low altitude is both an important input and output for self-consistent calculations of albedo particles resulting from the interaction of trapped and cosmic ray particles, with the upper atmosphere. In addition, data on the flux of light ions are needed to evaluate radiation damages on space-borne instruments and on space mission crews. In spite of that, sources of data on the flux of energetic ions at LEO are roughly limited to the AP-8 model, CREME/CREME96 codes and the SAMPEX, NOAA/TIROS satellites. The existing and operational European SAC-C/ICARE and PROBA-1/SREM instruments could also be potential sources for proton data at LEO. Although AP-8 and SAMPEX/PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes and they do not contain helium fluxes. Therefore, improved light ion radiation models are still needed. <br><br> In this paper we present a procedure to identify and measure the energy of ions that are not stopped in the NINA-2 instrument. Moreover, problems related to particles that cross the instrument in the opposite direction are addressed and shown to be a possible cause of particle misidentification. Measuring fluxes of low abundance elements like energetic helium ions requires a good characterisation of all possible sources of backgrounds in the detector. Hints to determine the several contributions to the background are presented herein and may be applied to extract an order of magnitude of energetic ions fluxes from existing data sets, while waiting for dedicated high performance instruments
Dark Matter Search Perspectives with GAMMA-400
GAMMA-400 is a future high-energy gamma-ray telescope, designed to measure
the fluxes of gamma-rays and cosmic-ray electrons + positrons, which can be
produced by annihilation or decay of dark matter particles, and to survey the
celestial sphere in order to study point and extended sources of gamma-rays,
measure energy spectra of Galactic and extragalactic diffuse gamma-ray
emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400
covers the energy range from 100 MeV to ~3000 GeV. Its angular resolution is
~0.01 deg(Eg > 100 GeV), and the energy resolution ~1% (Eg > 10 GeV). GAMMA-400
is planned to be launched on the Russian space platform Navigator in 2019. The
GAMMA-400 perspectives in the search for dark matter in various scenarios are
presented in this paperComment: 4 pages, 4 figures, submitted to the Proceedings of the International
Cosmic-Ray Conference 2013, Brazil, Rio de Janeir
The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
Precision measurements of the electron component in the cosmic radiation
provide important information about the origin and propagation of cosmic rays
in the Galaxy. Here we present new results regarding negatively charged
electrons between 1 and 625 GeV performed by the satellite-borne experiment
PAMELA. This is the first time that cosmic-ray electrons have been identified
above 50 GeV. The electron spectrum can be described with a single power law
energy dependence with spectral index -3.18 +- 0.05 above the energy region
influenced by the solar wind (> 30 GeV). No significant spectral features are
observed and the data can be interpreted in terms of conventional diffusive
propagation models. However, the data are also consistent with models including
new cosmic-ray sources that could explain the rise in the positron fraction.Comment: 11 pages, 3 figures, accepted for publication in PR
PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy
The satellite-borne experiment PAMELA has been used to make a new measurement
of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio which
extends previously published measurements down to 60 MeV and up to 180 GeV in
kinetic energy. During 850 days of data acquisition approximately 1500
antiprotons were observed. The measurements are consistent with purely
secondary production of antiprotons in the galaxy. More precise secondary
production models are required for a complete interpretation of the results.Comment: 11 pages, 3 figures, 1 table. Accepted for publication in Physical
Review Letter
Constraining Very Heavy Dark Matter Using Diffuse Backgrounds of Neutrinos and Cascaded Gamma Rays
We consider multi-messenger constraints on very heavy dark matter (VHDM) from
recent Fermi gamma-ray and IceCube neutrino observations of isotropic
background radiation. Fermi data on the diffuse gamma-ray background (DGB)
shows a possible unexplained feature at very high energies (VHE), which we have
called the "VHE Excess" relative to expectations for an attenuated power law
extrapolated from lower energies. We show that VHDM could explain this excess,
and that neutrino observations will be an important tool for testing this
scenario. More conservatively, we derive new constraints on the properties of
VHDM for masses of 10^3-10^10 GeV. These generic bounds follow from cosmic
energy budget constraints for gamma rays and neutrinos that we developed
elsewhere, based on detailed calculations of cosmic electromagnetic cascades
and also neutrino detection rates. We show that combining both gamma-ray and
neutrino data is essential for making the constraints on VHDM properties both
strong and robust. In the lower mass range, our constraints on VHDM
annihilation and decay are comparable to other results; however, our
constraints continue to much higher masses, where they become relatively
stronger.Comment: 33 pages, 21 figures, accepted for publication in JCA
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