1,599 research outputs found
Comparing phenomenological recipes with a microscopic model for the electric amplitude in strangeness photoproduction
Corrections to the Born approximation in photo-induced strangeness production
off a proton are calculated in a semi-realistic microscopic model. The vertex
corrections and internal contributions to the amplitude of the reaction are included on the one-loop level. Different
gauge-invariant phenomenological prescriptions for the modification of the Born
contribution via the introduction of form factors and contact terms are
discussed. In particular, it is shown that the popular minimal-substitution
method of Ohta corresponds to a special limit of the more realistic approach.Comment: 10 pages, 6 figures in the tex
Dynamics of diproton formation in the and reactions in the GeV region
Mechanisms for the production of diproton pairs, , in the
reaction are studied at proton beam energies 0.5 -- 2 GeV in
kinematics similar to those of backward elastic scattering. This reaction
provides valuable information on the short-range and interactions
that is complementary to that investigated in the well known and
processes. The reaction is related to the
subprocesses and using two different
one--pion--exchange (OPE) diagrams. Within both these models a reasonable
agreement could be obtained with the data below 1GeV. The similar energy
dependence of the and cross sections and the small
ratio of about 1.5% in the production of to deuteron final states
follow naturally within the OPE models.Comment: 10 pages, 7 figures, Late
Confirmation of taxonomic status of black yeast-like fungus by three gene phylogeny
Status of black melanin-containing yeast-like fungus Exophiala alcalophila isolated from microorganism complex of hermetic damaged in conditions of indoor high humidity in Kiev, Ukraine is proved by combined phylogenetic analysis based on sequences of the internal transcribed spacer 1 (ITS1), the 5.8S gene and the internal transcribed spacer 2 (ITS2) nrDNA, beta-tubulin gene and translation elongation factor 1-alpha gene. Sequences of the mentioned genes of Ukrainian specimen of E. alcalophila are for the first time submitted to the GenBank
A Possibility to Observe Short-Range NN Properties in the Deuteron Breakup
Quasi-binary reaction of the deuteron breakup with the final
proton-proton pair in the
state is analyzed at initial energies GeV in the kinematics
of backward elastic pd-scattering . On the basis of the main
mechanisms of the process, including initial and final state
interaction, we show that unpolarized cross section and spin observables of
this reaction exhibit important properties of the half-off-shell
-scattering amplitude, which are relevant to the nucleon-nucleon
interaction at short distances.Comment: 9 pages, Latex, 3 Postscript figure
Compton scattering on the nucleon at intermediate energies and polarizabilities in a microscopic model
A microscopic calculation of Compton scattering on the nucleon is presented
which encompasses the lowest energies -- yielding nucleon polarizabilities --
and extends to energies of the order of 600 MeV. We have used the covariant
"Dressed K-Matrix Model" obeying the symmetry properties which are appropriate
in the different energy regimes. In particular, crossing symmetry, gauge
invariance and unitarity are satisfied. The extent of violation of analyticity
(causality) is used as an expansion parameter.Comment: 35 pages, 15 figures, using REVTeX. Modified version to be published
in Phys. Rev. C, more extensive comparison with data for Compton scattering,
all results unchange
Rotational covariance and light-front current matrix elements
Light-front current matrix elements for elastic scattering from hadrons with
spin~1 or greater must satisfy a nontrivial constraint associated with the
requirement of rotational covariance for the current operator. Using a model
meson as a prototype for hadronic quark models, this constraint and its
implications are studied at both low and high momentum transfers. In the
kinematic region appropriate for asymptotic QCD, helicity rules, together with
the rotational covariance condition, yield an additional relation between the
light-front current matrix elements.Comment: 16 pages, [no number
СТАН МІКРОБІОЦЕНОЗУ НИЖНІХ СТАТЕВИХ ШЛЯХІВ ТА ЗАХОДИ ЙОГО КОРЕКЦІЇ У ЖІНОК З ПОЗАМАТКОВОЮ ВАГІТНІСТЮ.
The article presents some information on therapeutic approaches to the management of women with an ectopic pregnancy before, during and after surgery, to improve the efficiency of recovery microbiocenosis lower genital tract that can contribute to improving in general reproductive health of this group of patients.В статье представлена информация про особенности ведения женщин с внематочной беременностью до, во время и после оперативного лечения для повышения эффективности восстановления микробиоценоза нижних отделов половых путей, что в последующем может способствовать улучшению репродуктивного здоровья этой группы пациентов. У статті представлена інформація про особливості ведення жінок з позаматковою вагітністю до, під час і після оперативного лікування для підвищення ефективності відновлення мікробіоценозу нижніх відділів статевих шляхів, що в подальшому може сприяти поліпшенню репродуктивного здоров'я цієї групи пацієнтів
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