684 research outputs found
Dependence of Variational Perturbation Expansions on Strong-Coupling Behavior. Inapplicability of delta-Expansion to Field Theory
We show that in applications of variational theory to quantum field theory it
is essential to account for the correct Wegner exponent omega governing the
approach to the strong-coupling, or scaling limit. Otherwise the procedure
either does not converge at all or to the wrong limit. This invalidates all
papers applying the so-called delta-expansion to quantum field theory.Comment: Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of
paper (including all PS fonts) at
http://www.physik.fu-berlin.de/~kleinert/34
Measuring nutritional knowledge using Item Response Theory and its validity in European adolescents
Objective: To analyse the Nutritional Knowledge Test (NKT) using Item Response Theory (ITR) analysis and to assess the construct validity of the Nutritional Knowledge Scale (NKTS) and its associations with adolescent food group consumption and nutritional biomarkers.
DesignCross-sectional study: SettingMulticentre investigation conducted in ten European cities.ParticipantsAdolescents aged 12·5-17·5 years (n 3215) who completed over 75 % of the NKT.
Results: Factor analysis indicated that the NKT can be analysed with a one-dimensional model. Eleven out of twenty-three items from the NKT presented adequate parameters and were selected to be included in the NKTS. Nutrition knowledge was positively associated with consumption of fruits, cereals, dairy products, pulses, meat and eggs, and fish, as well as with blood concentrations of vitamin C, Ă-carotene, n-3 fatty acids, holo-transcobalamin, cobalamin and folate; nutrition knowledge was negatively associated with intake of olives and avocado, alcohol and savoury snacks.
Conclusions: The NKTS assessed nutritional knowledge adequately and it is proposed as a new tool to investigate this subject in future studies
Changes in vegetation cover of the Pantanal wetland detected by Vegetation Index: a strategy for conservation
Genetic diversity of cultivated accessions and wild species of rubber tree using ESTâSSR markers
Load-bearing capacity of a red-yellow latosol cultivated with coffee plants subjected to different weed managements
Oviposition preference of the neotropical brown stink bug Euschistus heros on artificial substrates of different colors
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
Data from the Pierre Auger Observatory are analyzed to search for
anisotropies near the direction of the Galactic Centre at EeV energies. The
exposure of the surface array in this part of the sky is already significantly
larger than that of the fore-runner experiments. Our results do not support
previous findings of localized excesses in the AGASA and SUGAR data. We set an
upper bound on a point-like flux of cosmic rays arriving from the Galactic
Centre which excludes several scenarios predicting sources of EeV neutrons from
Sagittarius . Also the events detected simultaneously by the surface and
fluorescence detectors (the `hybrid' data set), which have better pointing
accuracy but are less numerous than those of the surface array alone, do not
show any significant localized excess from this direction.Comment: Matches published versio
Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at GeV
We present first measurements of the evolution of the differential transverse
momentum correlation function, {\it C}, with collision centrality in Au+Au
interactions at GeV. {\it C} exhibits a strong dependence
on collision centrality that is qualitatively similar to that of number
correlations previously reported. We use the observed longitudinal broadening
of the near-side peak of {\it C} with increasing centrality to estimate the
ratio of the shear viscosity to entropy density, , of the matter formed
in central Au+Au interactions. We obtain an upper limit estimate of
that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.
Anålise de diversidade genética do gene da osteopontina em bovinos da raça girolando
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