35,832 research outputs found

    The diversity and welfare of older migrants in Europe

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    This paper sets the scene and provides a conceptual framework for the articles in this special issue. They present the findings of research on European residents who have reached or are on the threshold of old age and whose current circumstances have been strongly influenced by a migration across an international border. Such ‘older migrants’ are scattered throughout Europe and they have especially diverse characteristics. They include some of the most deprived and socially excluded, and some of the most affluent and accomplished, but all to a greater or lesser extent are disadvantaged through an interaction between social policies and their ‘otherness’ by living in a foreign country. Some claim attention through the severity of their unmet health and welfare needs and poor capacity to access advice and treatment, while the affluent groups are of great interest to social gerontology because of their enterprising, developmental and positive approaches to old age. They include among the most innovative of the latest generation of older people, who pursue new combinations of family responsibilities, leisure pursuits and income generation. The paper proposes that the concept ‘human capital’ summarises variations in preparedness for old age, that is, the resources by which people cope with demands for income, roles, treatment, care and support. A typology of the ‘welfare position’ of international migrants in contemporary Europe is presented

    Three body resonances in two meson-one baryon systems

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    We report four Σ\Sigma's and three Λ\Lambda's, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave (1/2)+(1/2)^+ resonances. We solve Faddeev equations in the coupled channel approach. The invariant mass of one of the meson-baryon pairs and that of the three particles have been varied and peaks in the squared three body TT-matrix have been found very close to the existing SS = -1, JP=1/2+J^P= 1/2^+ low lying baryon resonances. The input two-body tt-matrices for meson-meson and meson-baryon interaction have been calculated by solving the Bethe-Salpeter equation with the potentials obtained in the chiral unitary approach.Comment: corrected version, new channels evaluated, new references adde

    Transport coefficients of heavy baryons

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    We compute the transport coefficients (drag and momentum diffusion) of the low-lying heavy baryons Λc\Lambda_c and Λb\Lambda_b in a medium of light mesons formed at the later stages of high-energy heavy-ion collisions. We employ the Fokker-Planck approach to obtain the transport coefficients from unitarized baryon-meson interactions based on effective field theories that respect chiral and heavy-quark symmetries. We provide the transport coefficients as a function of temperature and heavy-baryon momentum, and analyze the applicability of certain nonrelativistic estimates. Moreover we compare our outcome for the spatial diffusion coefficient to the one coming from the solution of the Boltzmann-Uehling-Uhlenbeck transport equation and we find a very good agreement between both calculations. The transport coefficients for Λc\Lambda_c and Λb\Lambda_b in a thermal bath will be used in a subsequent publication as input in a Langevin evolution code for the generation and propagation of heavy particles in heavy-ion collisions at LHC and RHIC energies.Comment: 26 pages, 12 figures. Title changed. Small additions and corrections. Version accepted for publication by Physical Review D journa

    Solution to Faddeev equations with two-body experimental amplitudes as input and application to J^P=1/2^+, S=0 baryon resonances

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    We solve the Faddeev equations for the two meson-one baryon system ππN\pi\pi N and coupled channels using the experimental two-body tt-matrices for the πN\pi N interaction as input and unitary chiral dynamics to describe the interaction between the rest of coupled channels. In addition to the N∗(1710)N^*(1710) obtained before with the ππN\pi\pi N channel, we obtain, for Jπ=1/2+J^\pi=1/2^+ and total isospin of the three-body system I=1/2I=1/2, a resonance peak whose mass is around 2080 MeV and width of 54 MeV, while for I=3/2I=3/2 we find a peak around 2126 MeV and 42 MeV of width. These two resonances can be identified with the N∗(2100)N^* (2100) and the Δ(1910)\Delta (1910), respectively. We obtain another peak in the isospin 1/2 configuration, around 1920 MeV which can be interpreted as a resonance in the Na0(980)N a_0(980) and Nf0(980)N f_0(980) systems.Comment: published versio

    A Compound model for the origin of Earth's water

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    One of the most important subjects of debate in the formation of the solar system is the origin of Earth's water. Comets have long been considered as the most likely source of the delivery of water to Earth. However, elemental and isotopic arguments suggest a very small contribution from these objects. Other sources have also been proposed, among which, local adsorption of water vapor onto dust grains in the primordial nebula and delivery through planetesimals and planetary embryos have become more prominent. However, no sole source of water provides a satisfactory explanation for Earth's water as a whole. In view of that, using numerical simulations, we have developed a compound model incorporating both the principal endogenous and exogenous theories, and investigating their implications for terrestrial planet formation and water-delivery. Comets are also considered in the final analysis, as it is likely that at least some of Earth's water has cometary origin. We analyze our results comparing two different water distribution models, and complement our study using D/H ratio, finding possible relative contributions from each source, focusing on planets formed in the habitable zone. We find that the compound model play an important role by showing more advantage in the amount and time of water-delivery in Earth-like planets.Comment: Accepted for publication in The Astrophysical Journa
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