9,068 research outputs found
Coronary heart disease risks associated with high levels of HDL cholesterol.
BackgroundThe association between high-density lipoprotein cholesterol (HDL-C) and coronary heart disease (CHD) events is not well described in individuals with very high levels of HDL-C (>80 mg/dL).Methods and resultsUsing pooled data from 6 community-based cohorts we examined CHD and total mortality risks across a broad range of HDL-C, including values in excess of 80 mg/dL. We used Cox proportional hazards models with penalized splines to assess multivariable, adjusted, sex-stratified associations of HDL-C with the hazard for CHD events and total mortality, using HDL-C 45 mg/dL and 55 mg/dL as the referent in men and women, respectively. Analyses included 11 515 men and 12 925 women yielding 307 245 person-years of follow-up. In men, the association between HDL-C and CHD events was inverse and linear across most HDL-C values; however at HDL-C values >90 mg/dL there was a plateau effect in the pattern of association. In women, the association between HDL-C and CHD events was inverse and linear across lower values of HDL-C, however at HDL-C values >75 mg/dL there were no further reductions in the hazard ratio point estimates for CHD. In unadjusted models there were increased total mortality risks in men with very high HDL-C, however mortality risks observed in participants with very high HDL-C were attenuated after adjustment for traditional risk factors.ConclusionsWe did not observe further reductions in CHD risk with HDL-C values higher than 90 mg/dL in men and 75 mg/dL in women
Letters
While my wife and I were on a recent visit to the USSR, we visited with several refusenik families. These people were all members of the Jewish religion and were being helped, in some form or other, by synagogues and/or other Jewish organizations in the free world
A Buffer Stocks Model for Stabilizing Price of Staple Food with Considering the Expectation of Non Speculative Wholesaler
This paper is a study of price stabilization in the
staple food distribution system. All stakeholders experience
market risks due to some possibility causes of price volatility.
Many models of price stabilization had been developed by
employing several approaches such as floor-ceiling prices,
buffer funds, export or import taxes, and subsidies. In the
previous researches, the models were expanded to increase the
purchasing price for producer and decrease the selling price
for consumer. Therefore, the policy can influence the losses for
non-speculative wholesaler that is reflected by the descending
of selling quantity and ascending of the stocks. The objective of
this model is not only to keep the expectation of both producer
and consumer, but also to protect non-speculative wholesaler
from the undesirable result of the stabilization policy. A
nonlinear programming model was addressed to determine the
instruments of intervention program. Moreover, the result
shows that the wholesaler behavior affects the intervention
costs.
Index Terms Buffer stocks, Price stabilization, Nonlinear
programming, Wholesaler behavior
Universal simulation of Hamiltonian dynamics for qudits
What interactions are sufficient to simulate arbitrary quantum dynamics in a
composite quantum system? Dodd et al. (quant-ph/0106064) provided a partial
solution to this problem in the form of an efficient algorithm to simulate any
desired two-body Hamiltonian evolution using any fixed two-body entangling
N-qubit Hamiltonian, and local unitaries. We extend this result to the case
where the component systems have D dimensions. As a consequence we explain how
universal quantum computation can be performed with any fixed two-body
entangling N-qudit Hamiltonian, and local unitaries.Comment: 13 pages, an error in the "Pauli-Euclid-Gottesman Lemma" fixed, main
results unchange
Robust Ising Gates for Practical Quantum Computation
I describe the use of techniques based on composite rotations to combat
systematic errors in controlled phase gates, which form the basis of two qubit
quantum logic gates. Although developed and described within the context of
Nuclear Magnetic Resonanace (NMR) quantum computing these sequences should be
applicable to any implementation of quantum computation based on Ising
couplings. In combination with existing single qubit gates this provides a
universal set of robust quantum logic gates.Comment: 3 Pages RevTex4 including 2 figures. Will submit to PR
Specializing Interpreters using Offline Partial Deduction
We present the latest version of the Logen partial evaluation system for logic programs. In particular we present new binding-types, and show how they can be used to effectively specialise a wide variety of interpreters.We show how to achieve Jones-optimality in a systematic way for several interpreters. Finally, we present and specialise a non-trivial interpreter for a small functional programming language. Experimental results are also presented, highlighting that the Logen system can be a good basis for generating compilers for high-level languages
Quantum search without entanglement
Entanglement of quantum variables is usually thought to be a prerequisite for
obtaining quantum speed-ups of information processing tasks such as searching
databases. This paper presents methods for quantum search that give a speed-up
over classical methods, but that do not require entanglement. These methods
rely instead on interference to provide a speed-up. Search without entanglement
comes at a cost: although they outperform analogous classical devices, the
quantum devices that perform the search are not universal quantum computers and
require exponentially greater overhead than a quantum computer that operates
using entanglement. Quantum search without entanglement is compared to
classical search using waves.Comment: 9 pages, TeX, submitted to Physical Review Letter
Crossing the Brown Dwarf Desert Using Adaptive Optics: A Very Close L-Dwarf Companion to the Nearby Solar Analog HR 7672
We have found a very faint companion to the active solar analog HR 7672 (HD
190406; GJ 779; 15 Sge). Three epochs of high resolution imaging using adaptive
optics (AO) at the Gemini-North and Keck II Telescopes demonstrate that HR
7672B is a common proper motion companion, with a separation of 0.79" (14 AU)
and a 2.16 um flux ratio of 8.6 mags. Using follow-up K-band spectroscopy from
Keck AO+NIRSPEC, we measure a spectral type of L4.5+/-1.5. This is the closest
ultracool companion around a main sequence star found to date by direct
imaging. We estimate the primary has an age of 1-3 Gyr. Assuming coevality, the
companion is most likely substellar, with a mass of 55-78 Mjup based on
theoretical models. The primary star shows a long-term radial velocity trend,
and we combine the radial velocity data and AO imaging to set a firm
(model-independent) lower limit of 48 Mjup. In contrast to the paucity of brown
dwarf companions at <~4 AU around FGK dwarfs, HR 7672B implies that brown dwarf
companions do exist at separations comparable to those of the giant planets in
our own solar system. Its presence is at variance with scenarios where brown
dwarfs form as ejected stellar embryos. Moreover, since HR 7672B is likely too
massive to have formed in a circumstellar disk as planets are believed to, its
discovery suggests that a diversity of physical processes act to populate the
outer regions of exoplanetary systems.Comment: Astrophysical Journal, in pres
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