410 research outputs found
Resonances and the Weinberg--Tomozawa 56-baryon --35-meson interaction
Vector meson degrees of freedom are incorporated into the
Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian by using a scheme which
relies on spin--flavor SU(6) symmetry. The corresponding Bethe-Salpeter
approximation successfully reproduces previous SU(3)--flavor WT results for the
lowest-lying s--wave negative parity baryon resonances, and it also provides
some information on the dynamics of the heavier ones. Moreover, it also
predicts the existence of an isoscalar spin-parity bound
state (strangeness +1) with a mass around 1.7--1.8 GeV, unstable through
decay. Neglecting d-wave KN decays, this state turns out to be quite narrow
( MeV) and it might provide clear signals in reactions like
by looking at the three body
invariant mass.Comment: Talk given at the IVth International Conference on Quarks an Nuclear
Physics, Madrid, June 5th-10th 2006. Minor correction
Quark-mass dependence of baryon resonances
We study the quark-mass dependence of J^P = \frac12^- s-wave and J^P =
\frac32^- d-wave baryon resonances. Parameter-free results are obtained in
terms of the leading order chiral Lagrangian. In the 'heavy' SU(3) limit with
m_\pi =m_K \simeq 500 MeV the s-wave resonances turn into bound states forming
two octets plus a singlet representations of the SU(3) group. Similarly the
d-wave resonances turn into bound states forming an octet and a decuplet in
this limit. A contrasted result is obtained in the 'light' SU(3) limit with
m_\pi =m_K \simeq 140 MeV for which no resonances exist.Comment: 8 pages, three figures, talk presented at HYP200
Exotic dynamically generated baryons with C1
We follow a model based on the SU(8) symmetry for the interaction of mesons
with baryons. The model treats on an equal footing the pseudo-scalars and the
vector mesons, as required by heavy quark symmetry. The T-matrix calculated
within an unitary scheme in coupled channels has poles which are interpreted as
baryonic resonances.Comment: 5 pages. Proceedings for Chiral10 workshop, Valencia, June 21-24 201
Odd Parity Light Baryon Resonances
We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian
within a coupled channel unitary approach in order to calculate the T-matrix
for meson-baryon scattering in s-wave. The building blocks of the scheme are
the pion and nucleon octets, the rho nonet and the Delta decuplet. We identify
poles in this unitary T-matrix and interpret them as resonances. We study here
the non exotic sectors with strangeness S=0,-1,-2,-3 and spin J=1/2, 3/2 and
5/2. Many of the poles generated can be associated with known N, Delta, Sigma,
Lambda and Xi resonances with negative parity. We show that most of the
low-lying three and four star odd parity baryon resonances with spin 1/2 and
3/2 can be related to multiplets of the spin-flavor symmetry group SU(6). This
study allows us to predict the spin-parity of the Xi(1620), Xi(1690), Xi(1950),
Xi(2250), Omega(2250) and Omega(2380) resonances, which have not been
determined experimentally yet.Comment: New appendix and references adde
Influence of gender determinants on informal care and health service utilization in Spain: Ten years after the approval of the equality law
The existence of gender inequalities in health, in the use of health services, and in the development of informal care has been demonstrated throughout scientific literature. In Spain, a law was passed in 2007 to promote effective equality between men and women. Despite this, different studies have shown that the previous gender inequalities are still present in Spanish society. For all these reasons, the objective of this paper is to study the differences by sex in informal care and in the use of emergency care, and to identify the existence of gender inequalities in Spain 10 years after the adoption of the aforementioned equality law. In this case, we development a cross-sectional study based on the 2017 Spanish National Health Survey of the Spanish population aged 16 and over. To analyze the influence of gender determinants on informal care and emergency care utilization, logistic regressions were performed, model 1 was adjusted for age, and model 2 was further adjusted too by the variables of the Andersen care demand model. The results showed that informal care and the use of the emergency care continues to be higher in women than in men. Informal care in women was related to a higher level of education. In emergency care, the older the age, the lower the probability of utilization, and living in a rural municipality was related to a higher probability of utilization for both sexes. Finally, we concluded that there is still a need for studies that analyze gender inequalities in different contexts, such as the informal care and the use of health services. This is especially relevant in Spain, where economic changes have led to a change in roles, mainly for women, and new management strategies are needed to achieve equity in care and effective equality between men and women
Investigating the relationship between stress and self-rated health during the financial crisis and recession in 2008: The mediating role of job satisfaction and social support in Spain
Background: the 2008 financial crisis and subsequent recession had a strong impact on employment and certain health indicators, such as mental health. Many studies carried out with diverse samples attest to the negative influence of stress on health. However, few studies focus on stress and self-rated health among the Spanish workforce, or analyse which variables can act as a buffer against the negative effects of stress on self-perceived health. Aim: to analyse the mediator role of social support and job satisfaction in the relationship between work-related stress and self-rated health among the Spanish working population between 2006 and 2017. Method: repeated cross-sectional study using Spanish Surveys from 2006 to 2017, a total of 32.105 participants (47.4% women) aged 16 years and over (M = 42.3, SD = 10.7) answered a series of questions about work-related stress (PV), self-rated health (CV), job satisfaction, and social support (mediator variables) through the National Health Survey (NHS) prevalences of work-related stress, self-rated health, job satisfaction, and social support were calculated (standardised by age). We performed mediation/moderation analysis with Macro Process for SPSS to analyse the role of social support and job satisfaction in the relationship between self-rated health and work-related stress among the Spanish working population. Results: three mediation analyses were conducted, one for each time point in the study period. The results revealed a significant direct association between stress and job satisfaction. In the 2006 model, both job satisfaction and social support acted as mediators between stress and self-rated health, while in the 2011 and 2017 models, only job satisfaction acted as a mediator. The data reveal that the working population in Spain has a good capacity for resilience, since no drop in health indicators was observed. Conclusion: following the economic recession, employment has partially recovered. However, social and employment policies are required to help the population face the recent situation triggered by the Coronavirus crisis. Š 2021 by the authors. Licensee MDPI, Basel, Switzerland
D mesic nuclei
The energies and widths of several D^0 meson bound states for different
nuclei are obtained using a D-meson selfenergy in the nuclear medium, which is
evaluated in a selfconsistent manner using techniques of unitarized
coupled-channel theory. The kernel of the meson-baryon interaction is based on
a model that treats heavy pseudoscalar and heavy vector mesons on equal
footing, as required by heavy quark symmetry. We find D^0 bound states in all
studied nuclei, from 12C up to 208Pb. The inclusion of vector mesons is the
keystone for obtaining an attractive D-nucleus interaction that leads to the
existence of D^0-nucleus bound states, as compared to previous studies based on
SU(4) flavor symmetry. In some cases, the half widths are smaller than the
separation of the levels, what makes possible their experimental observation by
means of a nuclear reaction. This can be of particular interest for the future
PANDA@FAIR physics program. We also find a D^+ bound state in 12C, but it is
too broad and will have a significant overlap with the energies of the
continuum.Comment: 13 pages, 6 figures, 2 table
Clood CBR: towards microservices oriented case-based reasoning.
CBR applications have been deployed in a wide range of sectors, from pharmaceuticals; to defence and aerospace to IoT and transportation, to poetry and music generation; for example. However, a majority of these have been built using monolithic architectures which impose size and complexity constraints. As such these applications have a barrier to adopting new technologies and remain prohibitively expensive in both time and cost because changes in frameworks or languages affect the application directly. To address this challenge, we introduce a distributed and highly scalable generic CBR system, Clood, which is based on a microservices architecture. This splits the application into a set of smaller, interconnected services that scale to meet varying demands. Experimental results show that our Clood implementation retrieves cases at a fairly consistent rate as the casebase grows by several orders of magnitude and was over 3,700 times faster than a comparable monolithic CBR system when retrieving from half a million cases. Microservices are cloud-native architectures and with the rapid increase in cloud-computing adoption, it is timely for the CBR community to have access to such a framework
Double and the Interaction
The - effective interaction, in the channel , in the
nuclear medium is fitted to the available binding energies,
, of double hypernuclei:
He, Be and
B. The mesonic decay of these hypernuclei is also
investigated. Finally, this effective interaction is used to predict the
binding energies and mesonic decays widths of heavier double
hypernuclei.Comment: 4 pages, (latex file, postscript-file and 3 Postscript-figures
included
Low-lying even parity meson resonances and spin-flavor symmetry
A study is presented of the wave meson-meson interactions involving
members of the nonet and of the octet. The starting point is an
SU(6) spin-flavor extension of the SU(3) flavor Weinberg-Tomozawa Lagrangian.
SU(6) symmetry breaking terms are then included to account for the physical
meson masses and decay constants, while preserving partial conservation of the
axial current in the light pseudoscalar sector. Next, the matrix amplitudes
are obtained by solving the Bethe Salpeter equation in coupled-channel with the
kernel built from the above interactions. The poles found on the first and
second Riemann sheets of the amplitudes are identified with their possible
Particle Data Group (PDG) counterparts. It is shown that most of the low-lying
even parity PDG meson resonances, specially in the and sectors,
can be classified according to multiplets of the spin-flavor symmetry group
SU(6). The , and some resonances cannot be
accommodated within this SU(6) scheme and thus they would be clear candidates
to be glueballs or hybrids. Finally, we predict the existence of five exotic
resonances ( and/or ) with masses in the range 1.4--1.6 GeV,
which would complete the , , and multiplets of
SU(3)SU(2).Comment: 43 pages, 2 figures, 61 tables. Improved discussion of Section II. To
appear in Physical Review
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