6,631 research outputs found
A meson-baryon molecular interpretation for some excited baryons
We explore the possibility that some of the five narrow resonances
recently observed at LHCb could correspond to pentaquark states, structured as
meson-baryon bound states or molecules. The interaction of the low-lying
pseudoscalar mesons with the ground-state baryons in the charm ,
strangeness and isospin 0 sector is built from t-channel vector meson
exchange, using effective Lagrangians. The resulting s-wave coupled-channel
unitarized amplitudes show the presence of two structures with similar masses
and widths to those of the observed and .
The identification of these resonances with the meson-baryon bound states found
in this work would also imply assigning the values for their
spin-parity. An experimental determination of the spin-parity of the
would help in disentangling its structure, as the
quark-based models predict its spin-parity to be either or .Comment: 9 pages, 4 figure
The reaction in coupled channel chiral models up to next-to-leading order
We study the meson-baryon interaction in S-wave in the strangeness S=-1
sector using a chiral unitary approach based on a next-to-leading order chiral
SU(3) Lagrangian. We fit our model to the large set of experimental data in
different two-body channels. We pay particular attention to the reaction, where the effect of the next-to-leading order
terms in the Lagrangian are sufficiently large to be observed, since at tree
level the cross section of this reaction is zero. For these channels we improve
our approach by phenomenologically taking into account effects of the high spin
hyperonic resonances.Comment: 8 pages, 4 figures, presented at the II Russian-Spanish Congress
"Particle and Nuclear Physics at all Scales and Cosmology", Saint-Petersburg,
October 1-4, 2013. arXiv admin note: text overlap with arXiv:1311.5025; and
with arXiv:hep-ph/0505239 by other author
Which could be the role of Hybrid Fibre Coax in Next Generation Access networks?
Next generation access networks (NGAN) will support a renewed communication structure where opportunities lie in the provision of ubiquitous broadband connectivity, a wide variety of new applications, appealing contents and a general support to the sustainable growth of diverse sectors. From their deployment it is expected a wealth of innovations, jobs creation and a new wave of economic growth. In this paper we discuss which could be the role of Hybrid Fibre Coax (HFC) in the Next Generation Access Network (NGAN) roadmap. Thus, we propose a simplified model for making approximate cost calculations for HFC deployment based on the geographic and sociodemographic characteristics of Spain. Considering the latest evolution of HFC based on DOCSIS 3.0 from integrated (I-CMTS) towards modular (M-CMTS), the results from the model are compared with the most competitive NGAN for ultrabroadband speeds: Fibre to the Home (FTTH) based on Gigabitcapable Passive Optical Networks (GPON
Zebrafish as animal model for aquaculture nutrition research.
The aquaculture industry continues to promote the diversification of ingredients used in aquafeed in order to achieve a more sustainable aquaculture production system. The evaluation of large numbers of diets in aquaculture species is costly and requires time-consuming trials in some species. In contrast, zebrafish (Danio rerio) can solve these drawbacks as an experimental model, and represents an ideal organism to carry out preliminary evaluation of diets. In addition, zebrafish has a sequenced genome allowing the efficient utilization of new technologies, such as RNA-sequencing and genotyping platforms to study the molecular mechanisms that underlie the organism's response to nutrients. Also, biotechnological tools like transgenic lines with fluorescently labeled neutrophils that allow the evaluation of the immune response in vivo, are readily available in this species. Thus, zebrafish provides an attractive platform for testing many ingredients to select those with the highest potential of success in aquaculture. In this perspective article aspects related to diet evaluation in which zebrafish can make important contributions to nutritional genomics and nutritional immunity are discussed
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