500 research outputs found
Lattice calculation of SU(3) flavor breaking ratios in B - anti-B mixing
We present an unquenched lattice calculation for the SU(3) flavor breaking
ratios of the heavy-light decay constants and the matrix
elements. The calculation was performed on lattices with two
dynamical flavors of domain-wall quarks and inverse lattice spacing GeV. Heavy quarks were implemented using an improved lattice
formulation of the static approximation. In the infinite heavy-quark mass limit
we obtain , , where the first error is statistical and the second systematic.Comment: 23 pages, 8 figures, RevTeX4; mentioned existence of 1/m_b
corrections, minor changes improving readabilit
Improved interpolating fields for hadrons at non-vanishing momentum
We demonstrate that a reduction in the noise-to-signal ratio may be obtained
for hadrons at non-zero momenta whilst maintaining a good overlap with the
ground state through a generalisation of Gaussian/Wuppertal smearing. The use
of an anisotropic smearing wavefunction is motivated by the physical picture of
a boosted hadron.Comment: 7 pages, 6 figures, poster presented at the 30th International
Symposium on Lattice Field Theory (Lattice 2012), Cairns, Australia, June
24-29, 201
The importance of vitamin D and omega-3 PUFA supplementation: a nonpharmacologic immunomodulation strategy to halt autoimmunity
The large, randomized, double-blind, placebo-controlled trial VITAL (Vitamin D and omega 3 trial) recently confirmed that vitamin D and omega-3 polyunsaturated fatty acid (PUFA) co-supplementation (VIDOM) can reduce the incidence of autoimmune diseases. Based on these relevant results, this commentary summarizes the molecular mechanisms behind the anti-inflammatory and immunomodulatory properties of vitamin D and omega-3 PUFAs. We also describe the potential bidirectional interplay between vitamin D metabolism and omega-3 PUFA metabolism that underlies the rationale for VIDOM co-supplementation and that may contribute to enhance the anti-inflammatory and immunomodulatory actions of vitamin D and omega-3 PUFAs when these compounds are administered in combination
Non-perturbative renormalization of the static axial current in two-flavour QCD
We perform the non-perturbative renormalization of matrix elements of the
static-light axial current by a computation of its scale dependence in lattice
QCD with two flavours of massless O(a) improved Wilson quarks. The
regularization independent factor that relates any running renormalized matrix
element of the axial current in the static effective theory to the
renormalization group invariant one is evaluated in the Schroedinger functional
scheme, where in this case we find a significant deviation of the
non-perturbative running from the perturbative prediction. An important
technical ingredient to improve the precision of the results consists in the
use of modified discretizations of the static quark action introduced earlier
by our collaboration. As an illustration how to apply the renormalization of
the static axial current presented here, we connect the bare matrix element of
the current to the B_s-meson decay constant in the static approximation for one
value of the lattice spacing, a ~ 0.08 fm, employing large-volume N_f=2 data at
beta=5.3.Comment: 33 pages including figures and tables, latex2e, uses JHEP3.cls;
version published in JHEP, small additions, results unchange
The impact of vegan diet in the prevention and treatment of type 2 diabetes: A systematic review
A protective effect of vegan diets on health outcomes has been observed in previous studies, but its impact on diabetes is still debated. The aim of this review is to assess the relationship between vegan diets and the risk for type 2 diabetes (T2D) along with its effect on glycemic control and diabetes-related complications. In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, Pubmed and Cochrane library databases were systematically searched for all relevant studies. Seven observational and eight randomized controlled (RCTs) studies were included. The methodological quality of studies was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies and the Cochrane Risk of Bias Tool for RCTs. We found that a vegan diet is associated with lower T2D prevalence or incidence and in T2D patients decreases high glucose values and improves glucose homeostasis, as reported from the majority of included studies. This approach seems to be comparable to other recommended healthful eating models, but as it may have potential adverse effects associated with the long-term exclusion of some nutrients, appropriate nutritional planning and surveillance are recommended, particularly in specific groups of diabetic patients such as frail elderly, adolescents, and pregnant or breastfeeding women
Improved interpolating fields for hadrons at non-zero momentum
We generalize Gaussian/Wuppertal smearing in order to produce non-spherical
wave functions. We show that we can achieve a reduction in the noise-to-signal
ratio for correlation functions of certain hadrons at non-zero momentum, while
at the same time preserving a good projection on the ground state.Comment: 10 pages, 7 figures. Version accepted for publication in EPJ
Nucleon electromagnetic form factors in two-flavour QCD
We present results for the nucleon electromagnetic form factors, including
the momentum transfer dependence and derived quantities (charge radii and
magnetic moment). The analysis is performed using O(a) improved Wilson fermions
in Nf=2 QCD measured on the CLS ensembles. Particular focus is placed on a
systematic evaluation of the influence of excited states in three-point
correlation functions, which lead to a biased evaluation, if not accounted for
correctly. We argue that the use of summed operator insertions and fit
ans\"atze including excited states allow us to suppress and control this
effect. We employ a novel method to perform joint chiral and continuum
extrapolations, by fitting the form factors directly to the expressions of
covariant baryonic chiral effective field theory. The final results for the
charge radii and magnetic moment from our lattice calculations include, for the
first time, a full error budget. We find that our estimates are compatible with
experimental results within their overall uncertainties.Comment: 22 pages, 10 figures, citations modifie
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