69 research outputs found

    Baryonic Resonances from Baryon Decuplet-Meson Octet Interactions and the Exotic Resonance S=1, I=1, J^P=3/2-

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    Using the lowest order chiral Lagrangian we study s-wave interactions of the baryon decuplet with the octet of pseudoscalar mesons. We find two bound states in the flavour SU(3) limit corresponding to the octet and decuplet representations. These are found to split into eight different trajectories in the complex plane when the SU(3) symmetry is broken gradually. Finally, we are able to provide a reasonable description for a good number of 4-star 3/2- resonances listed by the Particle Data Group. In particular, the Xi(1820), the Lambda(1520) and the Sigma(1670) states are well reproduced. We predict a few other resonances and also evaluate the couplings of the observed resonances to the various channels from the residues at the poles of the scattering matrix from where partial decay widths into different channels can be evaluated.Comment: Talk given at 10th International Conference on the Structure of Baryons (Baryon 2004) at Palaiseau (France), 25-29 October 200

    Self-rated health in Europe and its determinants: Does generation matter?

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    Objectives: To analyse the influence of micro- and macro-factors on self-rated health, and the role of generation on this relationship. Methods: Cross-sectional study using data from European Health Interview Surveys from 14 European countries. Individuals were divided into four generations (“silent generation”, “baby boomers”, and “generation X” and “Y”). We conducted multilevel analyses for each generation to study the influence of individual and national explanatory variables on self-rated health. Results: Age showed an exponential effect in older generations. Education and employment presented the strongest association with low self-rated health, especially in “baby boomers” and women (low education: OR 3.5; 95% CI 3.2–3.9). Tobacco showed a negative effect in younger generations. Overweight and low physical activity were negatively associated with self-rated health regardless of generation. Countries from the Eastern welfare system showed the highest risk of low self-rated health and this association was higher in men for “silent generation” (OR 4.7; 95% CI 3.0–7.6). Conclusions: The influence of individual and national factors on self-rated health varies regarding generation. The target generation and the demographic structure of a country should be taken into account to develop more accurate health policies

    Recession, employment and self-rated health: a study on the gender gap

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    Objectives: Employment status and economic recession have been associated with negative effects on self-rated health, and this effect differs by gender. We analysed the effects of the Spanish economic recession in terms of self-rated health, its differential effect among genders and its influence on gender gap. Study design: Repeated cross-sectional study using Spanish health surveys (2001–2014). Methods: Logistic regression models were conducted to explore the association between self-rated health and employment status and its evolution over time and gender. To test the impact of the economic recession, pooled data regression models were conducted. Results: In this study, we considered 104,577 subjects. During the last 15 years, women have entered the labour market, leading to wide changes in the Spanish traditional family roles. Instead of an increasing proportion of women workers, gender employment differences persist. Therefore, in 2014, the prevalence of workers was 55.77% in men, whereas in women, it was 44.01%. Self-rated health trends during the economic recession differ by gender, with women improving slightly their self-rated health from a low self-rated health prevalence of 38.76% in 2001 to 33.78% in 2014. On the contrary, men seem more vulnerable to employment circumstances, which have led to substantial reduction in the gender gap. Conclusions: Although a gender gap persists, the change in socio-economic roles seems to increase women's self-rated health, reducing this gap. It is important to promote women's labour market inclusion, even in economic recession periods

    Annual variations of Castanea airbone pollen at thirteen spanish sites

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    Evolution of physical training in football

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    En el ámbito del deporte, ha venido siendo demostrado, que uno de los factores más importantes para que el deportista pueda rendir en las mejores condiciones es el de tener una buena preparación física. Independientemente del perfeccionamiento técnico, apoyo médico, nutrición, nuevos materiales, etc. La preparación física ha experimentado en los últimos años una evolución extraordinaria, tanto en cantidad como en calidad. En las últimas décadas las ciencias del deporte han evolucionado enormemente, producto de ello son los avances aparecidos en la preparación física en el fútbol a todos sus niveles. En este artículo se analizan las principales tendencias que históricamente han venido empleándose para la mejora de las diferentes cualidades físicas que implican la práctica de este deporte, con el objetivo de alcanzar el mejor rendimiento posible

    Photoproduction of KK^* for the study of Λ(1405)\Lambda(1405)

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    The photo-induced KK^* vector meson production is investigated for the study of the Λ(1405)\Lambda(1405) resonance. This reaction is particularly suited to the isolation of the second pole in the Λ(1405)\Lambda(1405) region which couples dominantly to the KˉN\bar K N channel. We obtain the mass distribution of the Λ(1405)\Lambda(1405) which peaks at 1420 MeV, and differs from the nominal one. Combined with several other reactions, like the πpK0πΣ\pi^- p \to K^0 \pi \Sigma which favours the first pole, this detailed study will reveal a novel structure of the Λ(1405)\Lambda(1405) state.Comment: 13 pages, 8 figures, 2 table

    The σ\sigma meson in a nuclear medium through two pion photoproduction

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    We present theoretical results for (γ,π0π0)(\gamma, \pi^0 \pi^0) production on nucleons and nuclei in the kinematical region where the scalar isoscalar ππ\pi \pi amplitude is influenced by the σ\sigma pole. The final state interaction of the pions modified by the nuclear medium produces a spectacular shift of strength of the two pion invariant mass distribution induced by the moving of the σ\sigma pole to lower masses and widths as the nuclear density increases.Comment: 14 pages, 7 figure

    Nuclear medium modification of the F2 structure function

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    We study the nuclear effects in the electromagnetic structure function F2(x,Q^2) in nuclei in the deep inelastic lepton nucleus scattering process by taking into account Fermi motion, binding, pion and rho meson cloud contributions. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations for nuclear matter. The ratios over deuteron structure function are obtained and compared with the recent JLAB results for light nuclei with special attention to the slope of the x distributions. This magnitude shows a non trivial A dependence and it is insensitive to possible normalization uncertainties. The results have also been compared with some of the older experiments using intermediate mass nuclei.Comment: 19 pages, 8 figures. This version matches accepted version to be published in Nuclear Physics

    Baryon Resonances

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    In this talk I show recent results on how many excited baryon resonances appear as systems of one meson and one baryon, or two mesons and one baryon, with the mesons being either pseudoscalar or vectors. Connection with experiment is made including a discussion on old predictions and recent results for the photoproduction of the Λ(1405)\Lambda(1405) resonance, as well as the prediction of one 1/2+1/2^+ baryon state around 1920 MeV which might have been seen in the γpK+Λ\gamma p \to K^+ \Lambda reaction.Comment: Talk given at the 10th International Conference on Hypernuclear and Strange Particle Physics, Tokai, Japan, Sptember 200

    Associations between udder health and reproductive performance in United Kingdom dairy cows

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    The objective of this research was to evaluate the relationship between udder health and reproductive performance in UK dairy cows. Data from 80 herds were restructured such that each unit of data represented a 2-d period during lactation where a cow was at risk of becoming pregnant. Multilevel discrete-time survival models were then used within a Bayesian framework to explore associations between reproductive outcomes and a variety of potential explanatory variables. Separate models were constructed using 2 different univariate binary outcomes: a cow becoming pregnant during a risk period and a cow becoming pregnant as a result of a given service. Potential explanatory variables included occurrence of clinical mastitis and a categorical representation of individual cow somatic cell count (SCC), both at a variety of timings relative to the risk period. Posterior predictions were used to assess model fit and to check model building assumptions. These demonstrated that the model represented the data well. Within-sample Monte Carlo simulation (i.e., use of the model to predict outcomes for cases within the data set, repeated over a large number of iterations) was used to illustrate results as posterior predicted relative risks. A negative association was found between reproductive performance and cases of clinical mastitis over a wide time frame relative to the risk period (from 28 d before to 70 d after the risk period). A similar negative association with the probability of a service leading to a pregnancy (pregnancy rate) was observed over the same time frame. Higher SCC recordings (i.e., those more likely to be associated with an intramammary infection) were also associated with decreased reproductive performance, especially where an individual cow SCC of greater than 399,000/mL was recorded in the 30 d following a risk period or service. This research demonstrates that both clinical and subclinical mastitis are associated with a reduction in reproductive performance, and that this influence varies in magnitude but can be exerted over a prolonged period
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