1,333 research outputs found
Delta isobar masses, large N_c relations, and the quark model
Motivated by recent remarks on the Delta+ mass and comparisons between the
quark model and relations based on large-N_c with perturbative flavor breaking,
two sets of Delta masses consistent with these constraints are constructed.
These two sets, based either on an experimentally determined mass splitting or
a quark model of isospin symmetry breaking, are shown to be inconsistent. The
model dependence of this inconsistency is examined, and suggestions for
improved experiments are made. An explicit quark model calculation and mass
relations based on the large-N_c limit with perturbative flavor breaking are
compared. The expected level of accuracy of such relations is realized in the
quark model, except for mass relations spanning more than one SU(6)
representation. It is shown that the Delta0 and Delta++ pole masses and Delta0
- Delta+ = (Delta- - Delta++)/3 about 1.5 MeV are more consistent with model
expectations than the analogous Breit-Wigner masses and their splittings.Comment: 10 pages, including 1 eps figure, revte
Joint modeling with time-dependent treatment and heteroskedasticity: Bayesian analysis with application to the Framingham Heart Study
Medical studies for chronic disease are often interested in the relation
between longitudinal risk factor profiles and individuals' later life disease
outcomes. These profiles may typically be subject to intermediate structural
changes due to treatment or environmental influences. Analysis of such studies
may be handled by the joint model framework. However, current joint modeling
does not consider structural changes in the residual variability of the risk
profile nor consider the influence of subject-specific residual variability on
the time-to-event outcome. In the present paper, we extend the joint model
framework to address these two heterogeneous intra-individual variabilities. A
Bayesian approach is used to estimate the unknown parameters and simulation
studies are conducted to investigate the performance of the method. The
proposed joint model is applied to the Framingham Heart Study to investigate
the influence of anti-hypertensive medication on the systolic blood pressure
variability together with its effect on the risk of developing cardiovascular
disease. We show that anti-hypertensive medication is associated with elevated
systolic blood pressure variability and increased variability elevates risk of
developing cardiovascular disease.Comment: 34 pages, 4 figure
Erythrocyte Long-Chain Omega-3 Fatty Acid Levels are Inversely Associated with Mortality and with Incident Cardiovascular Disease: The Framingham Heart Study
Background: The extent to which omega-3 fatty acid status is related to risk for death from any cause and for incident cardiovascular disease (CVD) remains controversial. Objective: To examine these associations in the Framingham Heart Study. Design: Prospective and observational. Setting: Framingham Heart Study Offspring cohort. Measurements: The exposure marker was red blood cell levels of eicosapentaenoic and docosahexaenoic acids (the Omega-3 Index) measured at baseline. Outcomes included mortality (total, CVD, cancer, and other) and total CVD events in participants free of CVD at baseline. Follow-up was for a median of 7.3 years. Cox proportional hazards models were adjusted for 18 variables (demographic, clinical status, therapeutic, and CVD risk factors). Results: Among the 2500 participants (mean age 66 years, 54% women), there were 350 deaths (58 from CVD, 146 from cancer, 128 from other known causes, and 18 from unknown causes). There were 245 CVD events. In multivariable-adjusted analyses, a higher Omega-3 Index was associated with significantly lower risks (P-values for trends across quintiles) for total mortality (P = .02), for non-CVD and non-cancer mortality (P = .009), and for total CVD events (P = .008). Those in the highest (\u3e6.8%) compared to those in the lowest Omega-3 Index quintiles (\u3c4.2%) had a 34% lower risk for death from any cause and 39% lower risk for incident CVD. These associations were generally stronger for docosahexaenoic acid than for eicosapentaenoic acid. When total cholesterol was compared with the Omega-3 Index in the same models, the latter was significantly related with these outcomes, but the former was not. Limitations: Relatively short follow-up time and one-time exposure assessment. Conclusions: A higher Omega-3 Index was associated with reduced risk of both CVD and all-cause mortality
Upanaha Sveda and its modification - A Critical Review
A fired building is best saved by pouring water , in the same way tropical problems are successfully managed by tropical treatment rather than systemic treatment. Upanaha is an ideal tropical treatment. Pradeha, Sankara/Panda Sveda, Bandhana are three varieties of Upanaha. It helps in reducing Vata Dosha, Sheeta (coldness), Shoola (pain), Sthambha (stiffness), Gouravatha (heaviness). It induces sweating and brings Doshavilayana. Sveda helps in Gatravinamana (increase the flexibility of body). Upanaha an Ayurvedic tropical treatment needs to evolve or adapt according to time so that it is easy to practice without changing its efficacy. Here an effort made to bring some modification in Upanaha
Stochastic series expansion method for quantum Ising models with arbitrary interactions
A quantum Monte Carlo algorithm for the transverse Ising model with arbitrary
short- or long-range interactions is presented. The algorithm is based on
sampling the diagonal matrix elements of the power series expansion of the
density matrix (stochastic series expansion), and avoids the interaction
summations necessary in conventional methods. In the case of long-range
interactions, the scaling of the computation time with the system size N is
therefore reduced from N^2 to Nln(N). The method is tested on a one-dimensional
ferromagnet in a transverse field, with interactions decaying as 1/r^2.Comment: 9 pages, 5 figure
Ceramide remodeling and risk of cardiovascular events and mortality
BackgroundRecent studies suggest that circulating concentrations of specific ceramide species may be associated with coronary risk and mortality. We sought to determine the relations between the most abundant plasma ceramide species of differing acyl chain lengths and the risk of coronary heart disease (CHD) and mortality in communityâbased samples. Methods and ResultsWe developed a liquid chromatography/mass spectrometry assay to quantify plasma C24:0, C22:0, and C16:0 ceramides and ratios of these veryâlongâchain/longâchain ceramides in 2642 FHS (Framingham Heart Study) participants and in 3134 SHIP (Study of Health in Pomerania) participants. Over a mean followâup of 6Â years in FHS, there were 88 CHD and 90 heart failure (HF) events and 239 deaths. Over a median followâup time in SHIP of 5.75Â years for CHD and HF and 8.24Â years for mortality, there were 209 CHD and 146 HF events and 377 deaths. In metaâanalysis of the 2 cohorts and adjusting for standard CHD risk factors, C24:0/C16:0 ceramide ratios were inversely associated with incident CHD (hazard ratio per average SD increment, 0.79; 95% confidence interval, 0.71â0.89; P<0.0001) and inversely associated with incident HF (hazard ratio, 0.78; 95% confidence interval, 0.61â1.00; P=0.046). Moreover, the C24:0/C16:0 and C22:0/C16:0 ceramide ratios were inversely associated with allâcause mortality (C24:0/C16:0: hazard ratio, 0.60; 95% confidence interval, 0.56â0.65; P<0.0001; C22:0/C16:0: hazard ratio, 0.65; 95% confidence interval, 0.60â0.70; P<0.0001). ConclusionsThe ratio of C24:0/C16:0 ceramides in blood may be a valuable new biomarker of CHD risk, HF risk, and allâcause mortality in the community
Semiclassical energy formulas for power-law and log potentials in quantum mechanics
We study a single particle which obeys non-relativistic quantum mechanics in
R^N and has Hamiltonian H = -Delta + V(r), where V(r) = sgn(q)r^q. If N \geq 2,
then q > -2, and if N = 1, then q > -1. The discrete eigenvalues E_{n\ell} may
be represented exactly by the semiclassical expression E_{n\ell}(q) =
min_{r>0}\{P_{n\ell}(q)^2/r^2+ V(r)}. The case q = 0 corresponds to V(r) =
ln(r). By writing one power as a smooth transformation of another, and using
envelope theory, it has earlier been proved that the P_{n\ell}(q) functions are
monotone increasing. Recent refinements to the comparison theorem of QM in
which comparison potentials can cross over, allow us to prove for n = 1 that
Q(q)=Z(q)P(q) is monotone increasing, even though the factor Z(q)=(1+q/N)^{1/q}
is monotone decreasing. Thus P(q) cannot increase too slowly. This result
yields some sharper estimates for power-potential eigenvlaues at the bottom of
each angular-momentum subspace.Comment: 20 pages, 5 figure
Recommended from our members
American Heart Association Cardiovascular Genome-Phenome Study: Foundational Basis and Program
The Unified Method: I Non-Linearizable Problems on the Half-Line
Boundary value problems for integrable nonlinear evolution PDEs formulated on
the half-line can be analyzed by the unified method introduced by one of the
authors and used extensively in the literature. The implementation of this
general method to this particular class of problems yields the solution in
terms of the unique solution of a matrix Riemann-Hilbert problem formulated in
the complex -plane (the Fourier plane), which has a jump matrix with
explicit -dependence involving four scalar functions of , called
spectral functions. Two of these functions depend on the initial data, whereas
the other two depend on all boundary values. The most difficult step of the new
method is the characterization of the latter two spectral functions in terms of
the given initial and boundary data, i.e. the elimination of the unknown
boundary values. For certain boundary conditions, called linearizable, this can
be achieved simply using algebraic manipulations. Here, we present an effective
characterization of the spectral functions in terms of the given initial and
boundary data for the general case of non-linearizable boundary conditions.
This characterization is based on the analysis of the so-called global
relation, on the analysis of the equations obtained from the global relation
via certain transformations leaving the dispersion relation of the associated
linearized PDE invariant, and on the computation of the large asymptotics
of the eigenfunctions defining the relevant spectral functions.Comment: 39 page
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