21,703 research outputs found

    Altruism, Fertility, and the Value of Children: Health Policy Evaluation and Intergenerational Welfare

    Get PDF
    This paper accounts for the value of children and future generations in the evaluation of health policies. This is achieved through the incorporation of altruism and fertility in "value of life" type of framework. We are able to express adults' willingness to pay for changes in child mortality and also to incorporate the welfare of future generations in the evaluation of current policies. Our model clarifies a series of puzzles from the literature on the "value of life" and on intergenerational welfare comparisons. We show that, by incorporating altruism and fertility into the analysis, the estimated welfare gain from recent reductions in mortality in the U.S. easily doubles.

    Combining exclusive semi-leptonic and hadronic B decays to measure |V_ub|

    Get PDF
    The Cabibbo-Kobayashi-Maskawa matrix element |V_ub| can be extracted from the rate for the semi-leptonic decay B -> pi + l + antineutrino_l, with little theoretical uncertainty, provided the hadronic form factor for the B -> pi transition can be measured from some other B decay. In here, we suggest using the decay B -> pi J\psi. This is a color suppressed decay, and it cannot be properly described within the usual factorization approximation; we use instead a simple and very general phenomenological model for the b d J\psi vertex. In order to relate the hadronic form factors in the B -> pi J\psi and B -> pi + l + antineutrino_l decays, we use form factor relations that hold for heavy-to-light transitions at large recoil.Comment: Latex, 7 pages, no figure

    Avaliação de ferramentas para detecção de interações epistáticas para fenótipos quantitativos em estudos de associação genômica ampla.

    Get PDF
    Variações genéticas presentes em uma população podem estar associadas a muitas características como susceptibilidade a doenças em humanos (ex: diabetes, câncer, e doenças psiquiátricas). Atualmente, tecnologias de genotipagem de baixo custo, baseadas em marcadores moleculares do tipo polimorfismo de base única Single Nucleotide Polymorphism (SNP) são utilizados para identificar variações desse tipo associadas com doenças. Tais estudos, são denominados, estudos de associação genômica ampla, Genome Wide Association Studies (GWAS). No caso de espécies de interesse agropecuário, essas variações genéticas estão relacionadas a características que podem impactar ganhos de qualidade e produção. Portanto, é de extrema importância a utilização de novos métodos computacionais para identificação desses marcadores, já que isto pode contribuir para a seleção de indivíduos superiores, considerando os traços fenotípicos de interesse em espécies animais utilizadas em programas de melhoramento coordenados pela Empresa Brasileira de Pesquisa Agropecuária (Embrapa)

    An extended formalism for preferential attachment in heterogeneous complex networks

    Full text link
    In this paper we present a framework for the extension of the preferential attachment (PA) model to heterogeneous complex networks. We define a class of heterogeneous PA models, where node properties are described by fixed states in an arbitrary metric space, and introduce an affinity function that biases the attachment probabilities of links. We perform an analytical study of the stationary degree distributions in heterogeneous PA networks. We show that their degree densities exhibit a richer scaling behavior than their homogeneous counterparts, and that the power law scaling in the degree distribution is robust in presence of heterogeneity

    On the quantumness of correlations in nuclear magnetic resonance

    Full text link
    Nuclear Magnetic Resonance (NMR) was successfully employed to test several protocols and ideas in Quantum Information Science. In most of these implementations the existence of entanglement was ruled out. This fact introduced concerns and questions about the quantum nature of such bench tests. In this article we address some issues related to the non-classical aspects of NMR systems. We discuss some experiments where the quantum aspects of this system are supported by quantum correlations of separable states. Such quantumness, beyond the entanglement-separability paradigm, is revealed via a departure between the quantum and the classical versions of information theory. In this scenario, the concept of quantum discord seems to play an important role. We also present an experimental implementation of an analogous of the single-photon Mach-Zehnder interferometer employing two nuclear spins to encode the interferometric paths. This experiment illustrate how non-classical correlations of separable states may be used to simulate quantum dynamics. The results obtained are completely equivalent to the optical scenario, where entanglement (between two field modes) may be present

    Group theory for structural analysis and lattice vibrations in phosphorene systems

    Get PDF
    Group theory analysis for two-dimensional elemental systems related to phosphorene is presented, including (i) graphene, silicene, germanene and stanene, (ii) dependence on the number of layers and (iii) two stacking arrangements. Departing from the most symmetric D6h1D_{6h}^{1} graphene space group, the structures are found to have a group-subgroup relation, and analysis of the irreducible representations of their lattice vibrations makes it possible to distinguish between the different allotropes. The analysis can be used to study the effect of strain, to understand structural phase transitions, to characterize the number of layers, crystallographic orientation and nonlinear phenomena.Comment: 24 pages, 3 figure
    corecore