1,313 research outputs found
Nonvolatile read/write memory element - A concept
Memory, with limited number of programming cycles, is achieved by using verticle, fusible links in series with oxide breakthrough elements. Memory elements are fabricated with integrated circuit technology and are ideal for low power digital computer application
B-meson decay constants: a more complete picture from full lattice QCD
We extend the picture of -meson decay constants obtained in lattice QCD
beyond those of the , and to give the first full lattice QCD
results for the , and . We use improved NonRelativistic QCD
for the valence quark and the Highly Improved Staggered Quark (HISQ) action
for the lighter quarks on gluon field configurations that include the effect of
, and quarks in the sea with quark masses going down to
physical values. For the ratio of vector to pseudoscalar decay constants, we
find = 0.941(26), = 0.953(23) (both
less than 1.0) and = 0.988(27). Taking correlated
uncertainties into account we see clear indications that the ratio increases as
the mass of the lighter quark increases. We compare our results to those using
the HISQ formalism for all quarks and find good agreement both on decay
constant values when the heaviest quark is a and on the dependence on the
mass of the heaviest quark in the region of the . Finally, we give an
overview plot of decay constants for gold-plated mesons, the most complete
picture of these hadronic parameters to date.Comment: 20 pages, 9 figures. Minor updates to the discussion in several
places and some additional reference
Opening the Rome-Southampton window for operator mixing matrices
We show that the running of operators which mix under renormalization can be
computed fully non-perturbatively as a product of continuum step scaling
matrices. These step scaling matrices are obtained by taking the "ratio" of Z
matrices computed at different energies in an RI-MOM type scheme for which
twisted boundary conditions are an essential ingredient. Our method allows us
to relax the bounds of the Rome-Southampton window. We also explain why such a
method is important in view of the light quark physics program of the RBC-UKQCD
collaborations. To illustrate our method, using n_f=2+1 domain-wall fermions,
we compute the non-perturbative running matrix of four-quark operators needed
in K->pipi decay and neutral kaon mixing. Our results are then compared to
perturbation theory.Comment: 8 pages, 7 figures. v2: PRD version, minor changes and few references
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About the parabolic relation existing between the skewness and the kurtosis in time series of experimental data
In this work we investigate the origin of the parabolic relation between
skewness and kurtosis often encountered in the analysis of experimental
time-series. We argue that the numerical values of the coefficients of the
curve may provide informations about the specific physics of the system
studied, whereas the analytical curve per se is a fairly general consequence of
a few constraints expected to hold for most systems.Comment: To appear in Physica Script
One-loop matching of improved four-fermion staggered operators with an improved gluon action
We present results for one-loop matching factors of four-fermion operators
composed of HYP-smeared staggered fermions. We generalize previous calculations
by using the tree-level improved Symanzik gauge action. These results are
needed for our companion numerical calculation of and related matrix
elements. We find that the impact on one-loop matching factors of using the
improved gluon action is much smaller than that from the use of either HYP
smearing or mean-field improvement. The one-loop coefficients for mean-field
improved, HYP-smeared operators with the Symanzik gauge action have a maximum
magnitude of , indicating that perturbation theory is
reasonably convergent.Comment: 11 pages, 16 figures, references are update
The relative influence of demographic, individual, social, and environmental factors on physical activity among boys and girls
Background: This study aimed to evaluate the associations of selected demographic, individual, social, and environmental factors with moderate-to-vigorous physical activity (MVPA) in a sample of children and adolescents.
Methods: MVPA was assessed among youth (n = 294) 10-17-years-old using the ActiGraph accelerometer. Youth completed measures of demographic and individual variables related to physical activity (PA), perceived social support by parents and peers, and perceived neighborhood characteristics. Parents completed the long-form of the International Physical Activity Questionnaire. The Physical Activity and Media Inventory was used to measure the home environment and Geographical Information Systems software was used to measure the physical neighborhood environment. Bivariate correlations and hierarchical multiple regression were conducted stratified by gender.
Results: Boys participated in significantly more MVPA than girls. In hierarchical analyses, peer support, home PA equipment, and temperature were significantly associated with MVPA among boys whereas distance to the school they attended was associated with MVPA among girls. The final models accounted for 25% and 15% of the variance in MVPA among boys and girls, respectively.
Conclusions: Important differences exist among the individual, social, and environmental factors related to MVPA between boys and girls. Boys\u27 levels of activity appear to be influenced by factors closely linked to unstructured and social types of activities whereas girls\u27 activities relate to internal and external barriers as well as their proximity to their schools. The prospective contribution of these important individual, social, and environmental factors to changes in MVPA among children and adolescents remains to be determined
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