Moments of Structure Functions in Full QCD

Moments of the quark density distribution, moments of the quark helicity distribution, and the tensor charge are calculated in full QCD. Calculations of matrix elements of operators from the operator product expansion have been performed on $16^3 \times 32$ lattices for Wilson fermions at $\beta = 5.6$ using configurations from the SESAM collaboration and at $\beta = 5.5$ using configurations from SCRI. One-loop perturbative renormalization corrections are included. Selected results are compared with corresponding quenched calculations and with calculations using cooled configurations.Comment: Lattice 2000 (Hadronic Matrix Elements), 4 pages, 5 figure

B_K from quenched overlap QCD

We present an exploratory calculation of the standard model Delta S=2 matrix element relevant for indirect CP violation in K -> pi pi decays. The computation is performed with overlap fermions in the quenched approximation at beta=6.0 on a 16^3x32 lattice. The resulting bare matrix element is renormalized non-perturbatively. Our preliminary result is B_K^{NDR}(2 GeV)=0.61(7), where the error does not yet include an estimate of systematic uncertainties.Comment: 3 pages, 2 figures, Lattice2002(matrixel). Parallel session talk by L. Lellouch at the 20th International Symposium on Lattice Field Theory (Lattice 2002), Boston, Massachusetts, 24-29 June 200

Recent advances in analytical approaches for the standardization and quality of polyphenols of propolis

Analytical approaches utilized for the characterization of polyphenols from propolis useful for the determination of its quality is investigated in this study. A qualitative and quantitative evaluation of propolis bioactive molecules is of interest in medicine and nutraceuticals. Recent powerful analytical techniques are of great utility to separate and quantify polyphenols in extracts and finished products due to their capacity to produce typical fingerprints and a reliable identification of many components. According to this, an HPLC-UV-MS procedure was validated and applied for the characterization and quantification of bioactive substances in propolis and for an accurate assessment of their content in extract samples. By using this analytical approach, we obtained specific compositions related to brown propolis acquired from different geographic areas (and preparations and treatment). This is more important by considering the scientific opinion of European Food Safety Authority (EFSA) which provided a negative response related to health claims of propolis and its polyphenols. These results prove that HPLC-MS is an attractive tool for the standardization and quality control of propolis and may be realistically applied to screen raw material and to evaluate finished commercial preparations and nutraceutical benefits

Numerical Exploration of the RI/MOM Scheme Gauge Dependence

The gauge dependence of some fermion bilinear RI/MOM renormalization constants is studied by comparing data which have been gauge-fixed in two different realizations of the Landau gauge and in a generic covariant gauge. The very good agreement between the various sets of results and the theory indicates that the numerical uncertainty induced by the lattice gauge-fixing procedure is below the statistical errors of our data sample which is of the order of (1-1.5)%.Comment: 3 pages, 2 figures, Lattice2002(theoretical

On the discretization of physical momenta in lattice QCD

The adoption of two distinct boundary conditions for two fermions species on a finite lattice allows to deal with arbitrary relative momentum between the two particle species, in spite of the momentum quantization rule due to a limited physical box size. We test the physical significance of this topological momentum by checking in the continuum limit the validity of the expected energy-momentum dispersion relations.Comment: 9 pages, 3 figures; references added; no changes in text or results; version accepted for pubblication in Phys. Lett.

Moments of Nucleon Light Cone Quark Distributions Calculated in Full Lattice QCD

Moments of the quark density, helicity, and transversity distributions are calculated in unquenched lattice QCD. Calculations of proton matrix elements of operators corresponding to these moments through the operator product expansion have been performed on $16^3 \times 32$ lattices for Wilson fermions at $\beta = 5.6$ using configurations from the SESAM collaboration and at $\beta = 5.5$ using configurations from SCRI. One-loop perturbative renormalization corrections are included. At quark masses accessible in present calculations, there is no statistically significant difference between quenched and full QCD results, indicating that the contributions of quark-antiquark excitations from the Dirac Sea are small. Close agreement between calculations with cooled configurations containing essentially only instantons and the full gluon configurations indicates that quark zero modes associated with instantons play a dominant role. Naive linear extrapolation of the full QCD calculation to the physical pion mass yields results inconsistent with experiment. Extrapolation to the chiral limit including the physics of the pion cloud can resolve this discrepancy and the requirements for a definitive chiral extrapolation are described.Comment: 53 Pages Revtex, 26 Figures, 9 Tables. Added additional reference and updated referenced data in Table I

Factors influencing the first thousand days of life

The first 1,000 days is a vulnerable phase in which parents, institutions and health professionals should create early interventions for the proper development and promotion of good health

One loop matching coefficients for a variant overlap action--and some of its simpler relatives

I present one-loop perturbative calculations of matching coefficients between matrix elements in continuum regulated QCD and lattice QCD with overlap fermions, with emphasis a recently-proposed variant discretization of the overlap. These fermions have extended (``fat link'') gauge connections. The scale for evaluation of the running coupling constant (in the context of the Lepage-Mackenzie fixing scheme) is also given. A variety of results (for additive mass renormalization, local currents, and some non-penguin four-fermion operators) for naive, Wilson, clover, and overlap actions are shown.Comment: 17 pages, Revtex, 11 postscript figures. COLO-HEP-48

Mechano-chemical activation: an ecological safety process in the production of materials to stone conservation

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