249 research outputs found
The decay of the and its nature as a molecule
We investigate the decay of with the assumption
that the is dynamically generated from the
interaction. In addition to the tree level diagrams that proceed via , we take into account also the final
state interactions of and . The
partial decay width and mass distributions of are
evaluated. We get a value for the partial decay width which, within errors, is
in fair agreement with the experimental result. The contribution from the tree
level diagrams is dominant, but the final state interactions have effects in
the mass distributions. The predicted mass distributions are significantly
different from phase space and tied to the nature of the
state.Comment: Published versio
Study of and interactions in and relationship to the , states
We use the local hidden gauge approach in order to study the and
interactions for isospin I=1. We show that both interactions via
one light meson exchange are not allowed by OZI rule and, for that reason, we
calculate the contributions due to the exchange of two pions, interacting and
noninteracting among themselves, and also due to the heavy vector mesons. Then,
to compare all these contributions, we use the potential related to the heavy
vector exchange as an effective potential corrected by a factor which takes
into account the contribution of the others light mesons exchange. In order to
look for poles, this effective potential is used as the kernel of the
Bethe-Salpeter equation. As a result, for the interaction we find
a loosely bound state with mass in the range MeV, very close to
the experimental value of the reported by Belle Collaboration. For
the case, we find a cusp at MeV for all spin
cases.Comment: 23 pages, 20 figure
Wave functions of composite hadron states and relationship to couplings of scattering amplitudes for general partial waves
In this paper we present the connection between scattering amplitudes in
momentum space and wave functions in coordinate space, generalizing previous
work done for s-waves to any partial wave. The relationship to the wave
function of the residues of the scattering amplitudes at the pole of bound
states or resonances is investigated in detail. A sum rule obtained for the
couplings provides a generalization to coupled channels, any partial wave and
bound or resonance states, of Weinberg's compositeness condition, which was
only valid for weakly bound states in one channel and s-wave. An example,
requiring only experimental data, is shown for the meson indicating that
it is not a composite particle of but something else
Isospin breaking and - mixing in the reaction
We make a theoretical study of the and
reactions with an aim to determine the
isospin violation and the mixing of the and resonances.
We make use of the chiral unitary approach where these two resonances appear as
composite states of two mesons, dynamically generated by the meson-meson
interaction provided by chiral Lagrangians. We obtain a very narrow shape for
the production in agreement with a BES experiment. As to the amount
of isospin violation, or and mixing, assuming constant
vertices for the primary and
production, we find results which
are much smaller than found in the recent experimental BES paper, but
consistent with results found in two other related BES experiments. We have
tried to understand this anomaly by assuming an I=1 mixture in the
wave function, but this leads to a much bigger width of the mass
distribution than observed experimentally. The problem is solved by using the
primary production driven by followed by , which induces an extra singularity in the loop functions needed to
produce the and resonances. Improving upon earlier work
along the same lines, and using the chiral unitary approach, we can now predict
absolute values for the ratio which are in fair agreement with experiment. We also show that the same
results hold if we had the resonance or a mixture of these two
states, as seems to be the case in the BES experiment
A Link between Parental Psychopathology and Preschool Depression: Take Care of Parents to Take Care of Children
There is a lot of evidence in the literature showing that early-onset depression determines an emotional and cognitive vulnerability for psychiatric disorders in subsequent years.
Aims: The first aim of this outcome research was to analyze the impact of parental support treatment in a sample of depressed preschool children divided into two groups of comparison (under-reactive and over-reactive) through evolution in the Clinical Global Impression (CGI). The second aim was to analyze the correlation between the presence of parental psychopathology and the severity of children's disorders.
Methods: Our clinical sample consisted of 32 preschool-age children with a final diagnosis of MDD. The children's assessment included a psychiatric assessment to establish a diagnosis of MDD, confirmed by means of a semi-structured interview, which was administered again one month after the end of parental treatment. All the parents began a six-month parent training treatment conducted by experienced child psychiatrists, whereas children were not treated. During this period, the Clinical Global Impression Scale (CGI) was filled out monthly in order to observe the evolution of the children's disorders.
Results: Post-hoc tests showed a significant difference from before the treatment to after the treatment only in the over-reactive group (p = 0.00). Regarding parental psychiatric disorders, in the over-reactive group, only 3 children had no parents with psychopathology. In the under-reactive group, no child lacked a parent with psychopathology.
Conclusion: Parent training treatment seems to be a valid intervention to improve preschool depression, especially in over-reactive groups, and to prevent dysfunctional parental styles connected to parental psychopathology
Functional assessment of cancer therapy questionnaire for breast cancer (FACT-B+4): Italian version validation
BACKGROUND:
Improvements in breast cancer diagnosis and treatment led to an increased incidence of survivors' rate. The healthcare system has to face new problems related not only to the treatment of the disease, but also to the management of the quality of life after the diagnosis. The aim of this study was to validate the Italian version of the Functional Assessment of Cancer Therapy - Breast (FACT-B+4) questionnaire and to evaluate its reliability.
METHODS:
The questionnaire was administered twice, with an interval of three days between each administration, to a cohort of women of the Breast Surgical Unit, PoliclincoUmberto I. Cronbach's alpha was used as a measure of the internal consistency of the Italian version.
RESULTS:
The Italian version of the tool was administered to 55 subjects. The Cronbach's alpha for most scores registered values >0.7, both at baseline and at the follow-up analysis, therefore the subscale showed good internal consistency.
CONCLUSIONS:
The Italian version of FACT-B+4 demonstrated acceptable reliability properties in the Breast Unit patients. The use of this questionnaire seemed to be effective and in line with the results derived from the English and Spanishversions. Internal consistency and validity had similar performance results
The decay in the molecular picture
From a picture of the X(3872) where the resonance is a bound state of
, we evaluate the decay width into the
channel, which is sensitive to the internal structure of this state.
For this purpose we evaluate the loops through which the X(3872) decays into
its components, and the and the photon are radiated from these
components. We use the local hidden gauge approach extrapolated to SU(4) with a
particular SU(4) breaking. The radiative decay involves anomalous couplings and
we obtain acceptable values which are compared to experiments and results of
other calculations.
Simultaneusly, we evaluate the decay rate for the X(3872) into and , and the results obtained for the ratio of these
decay widths are compatible with the experiment.
We also show the grossly unacceptable results that come from taking only the
component.Comment: 17 pages, 2 figure
Meson-baryon components in the states of the baryon decuplet
We apply an extension of the Weinberg compositeness condition on partial waves of L = 1 and resonant states to determine the weight of the meson-baryon component in the Delta(1232) resonance and the other members of the baryon decuplet. We obtain an appreciable weight of pi N in the Delta(1232) wave function, of the order of 60%, which looks more natural when one recalls that experiments on deep inelastic and Drell Yan give a fraction of pi N component of 34% for the nucleon. We also show that, as we go to higher energies in the members of the decuplet, the weights of the meson-baryon component decrease and they already show a dominant part for a genuine, non-meson-baryon, component in the wave function. We write a section to interpret the meaning of the Weinberg sum rule when it is extended to complex energies and another one for the case of an energy-dependent potential
Development of the Gastrointestinal Tract in Newborns as a Challenge for an Appropriate Nutrition: A Narrative Review
The second and third trimesters of pregnancy are crucial for the anatomical and functional development of the gastrointestinal (GI) tract. If premature birth occurs, the immaturity of the digestive and absorptive processes and of GI motility represent a critical challenge to meet adequate nutritional needs, leading to poor extrauterine growth and to other critical complications. Knowledge of the main developmental stages of the processes involved in the digestion and absorption of proteins, carbohydrates, and lipids, as well as of the maturational phases underlying the development of GI motility, may aid clinicians to optimize the nutritional management of preterm infants. The immaturity of these GI systems and functions may negatively influence the patterns of gut colonization, predisposing to an abnormal microbiome. This, in turn, further contributes to alter the functional, immune, and neural development of the GI tract and, especially in preterm infants, has been associated with an increased risk of severe GI complications, such as necrotizing enterocolitis. Deeper understanding of the physiological colonization patterns in term and preterm infants may support the promotion of these patterns and the avoidance of microbial perturbations associated with the development of several diseases throughout life. This review aims to provide a global overview on the maturational features of the main GI functions and on their implications following preterm birth. We will particularly focus on the developmental differences in intestinal digestion and absorption functionality, motility, gut–brain axis interaction, and microbiomes
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