6,179 research outputs found

    Possible scenario for MaVaN's as the only neutrino flavor conversion mechanism in the Sun

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    Mass Varying neutrino mechanisms were proposed to link the neutrino mass scale with dark energy, addressing the coincidence problem. In some scenarios this mass can present a dependence on the baryonic density felt by neutrinos, creating an effective neutrino mass that depends both on the neutrino and baryonic densities. In this article we investigate the possibility that a neutrino effective mass is the only flavour conversion mechanism acting in neutrino oscillation experiments. We present a parameterization on the environmental effects on neutrino mass that produces the right flavour conversion probabilities for solar and terrestrial neutrinos experiments.Comment: 12 pages, 4 figure

    Performance and Congestion Analysis of the Portuguese Hospital Services

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    The health care services have been characterised by a growing demand by the citizens leading to the need of more and more resources. Population aging, new pathologies and drugs as well as new treatments are some of the major factors for this. However, in hospitals, for example, consumption of a large number of inputs frequently has not corresponded to the production of the same or more proportion of outputs. Sometimes, the outputs even decline with the increase of inputs due to the influence of the congestion effect on efficiency. The heavy burden of the health sector on the state budget brings about the interest of research over its efficiency. This paper aims to assess the performance of the Portuguese hospitals and particularly the contribution of the congestion effect. We use the non-parametric technique of data envelopment analysis (DEA) for this purpose and a double-bootstrap procedure to take into account the influence of operational environment on efficiency. Afterwards, by comparing three different approaches we determine the importance of congestion in efficiency measurement and discuss its computation methodologically. The results suggest significant levels of inefficiency in 68 major Portuguese hospitals for the year 2005 and more than half of them were found to be congested.Hospitals; congestion; efficiency; DEA; Portugal

    Influence of bed elevation discordance on flow patterns and head losses in an open-channel confluence

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    Confluences play a major role in the dynamics of networks of natural and man-made open channels, and field measurements on river confluences reveal that discordance in bed elevation is common. Studies of schematized confluences with a step at the interface between the tributary and the main channel bed reveal that bed elevation discordance is an important additional control for the confluence hydrodynamics. This study aimed to improve understanding of the influence of bed elevation discordance on the flow patterns and head losses in a right-angled confluence of an open channel with rectangular cross-sections. A large eddy simulation (LES)-based numerical model was set up and validated with experiments by others. Four configurations with different bed discordance ratios were investigated. The results confirm that, with increasing bed elevation discordance, the tributary streamlines at the confluence interface deviate less from the geometrical confluence angle, the extent of the recirculation zone (RZ) gets smaller, the ratio of the water depth upstream to that downstream of the confluence decreases, and the water level depression reduces. The bed elevation discordance also leads to the development of a large-scale structure in the lee of the step. Despite the appearance of the large-scale structure, the reduced extent of the RZ and associated changes in flow deflection/contraction reduce total head losses experienced by the main channel with an increase of the bed discordance ratio. It turns out that bed elevation discordance converts the lateral momentum from the tributary to streamwise momentum in the main channel more efficiently. (C) 2019 Hohai University. Production and hosting by Elsevier B.V

    A diversidade de práticas na relação entre género, conflito e negociação

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    A presente comunicação procura, em primeiro lugar, balizar sumariamente os conceitos de conflito social e negociação. Seguidamente, entra-se numa análise de pendor crítico construtivo quanto ao “estado da arte” sobre as abordagens relativas aos estilos de gestão de conflito. Finalmente, reflecte-se sobre a relação existente entre conflito, negociação e a variável género, relação essa que suscitou mais recentemente a curiosidade psicossociológica do investigador, procurando-se apresentar algumas ideias essenciais sobre a natureza e especificidade desse mesmo relacionamento. The present communication aims at, firstly, defining briefly the concepts of social conflict and negotiation. then, there is a critical-constructive analysis about “the state of art” on the conflict management approaches. Finally, we reflect on the relationship between conflict, negotiation and the variable gender which has recently aroused the psycho-sociological curiosity of the researcher. We try to present some relevant ideas on the nature and specificity of that relationship

    The Technology of Skill Formation

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    his paper presents formal models of child development that capture the essence of recent findings from the empirical literature on child development. The goal is to provide theoretical frameworks for interpreting the evidence from a vast empirical literature, for guiding the next generation of empirical studies and for formulating policy. We start from the premise that skill formation is a life-cycle process. It starts in the womb and goes on throughout most of the adult life. Families and firms have a role in this process that is at least as important as the role of schools. There are multiple skills and multiple abilities that are important for adult success. Abilities are both inherited and created, and the traditional debate of nature versus nurture is outdated and scientifically obsolete. The technology of skill formation has two additional important characteristics. The first one is that IQ and behavior are more plastic at early ages than at later ages. Furthermore, behavior is much more malleable than IQ as individuals age. The second is that human capital investments are complementary over time. Early investments increase the productivity of later investments. Early investments are not productive if they are not followed up by later investments. The returns to investing early in the life cycle are high. Remediation of inadequate early investments is difficult and very costlyhuman capital, life cycle of skill formation

    Inequality and Growth: Uncovering the main conclusions from the empirics

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    The theme of the relationship between inequality and economic growth has gained considerable attention among economists over the last two decades. In this paper, we analyse the effect of inequality on growth, whose related literature has been producing inconclusive results. After an exhaustive study of the major empirical works in this specific research area, we are able not only to advance with some potential explanations for the apparent lack of consensus on the empirical assessment of the inequality-growth relationship, but also to achieve a better understanding of the nature of this relationship and the forces underlying it. We conclude that the disparities found in the results of the estimation of the reduced-form relationship are most likely due to three dimensions: differences in the estimation techniques, the countries and the periods included in the sample, and the variable used to measure inequality. The last two aspects have particularly important implications. First, country/region specificities play a crucial role in the relationship between inequality and growth, so more emphasis should be put on the estimation of such a relationship on a national/regional basis, rather than trying to establish universal patterns. Second, the time horizon of the analysis should be carefully chosen, as different transmission channels from inequality to growth tend to operate differently in the short and in the long-run. Third, the fact that inequality in wealth distribution has a stronger negative effect on growth than inequality in income distribution may indicate that the channels through which inequality affects growth are not the same in both distributions. Therefore, we argue that in order to produce an accurate assessment of both the reduced-form relationship and the underlying transmission channels these aspects should be accordingly considered, which has not been the case in most of the empirical literature.inequality, economic growth, transmission channels, income distribution, wealth distribution, taxation

    Definition of a technique for characterizing the expected benefits of a project

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    In the changing global economic landscape, it is vital for organizations to stay competitive and reduce their costs. Replacing outdated technology, improving business processes, and implementing new programs are some examples of activities that organizations have to do to face such demands. The increased pressure to create capital, business, and technology projects within budget, specifications, and schedule makes it necessary to avoid or at least soften risks and challenges that could compromise the desired outcomes of the project. So, it's each time more and more important to plan as much as it is possible to predict, including the benefits management. This paper aims to develop a proposition of a technique that allows the user to predict and monitor all inherent benefits to the conception of a project, aiding the work team in making decisions (especially about the feasibility of the project, or by other words, the go/no go decision), comparing projects and identifying optimizations opportunities.FCT - Fundação para a Ciência e a Tecnologia(UIDB/00319/ 2020

    Shadows and strong gravitational lensing: a brief review

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    For ultra compact objects (UCOs), Light Rings (LRs) and Fundamental Photon Orbits (FPOs) play a pivotal role in the theoretical analysis of strong gravitational lensing effects, and of BH shadows in particular. In this short review, specific models are considered to illustrate how FPOs can be useful in order to understand some non-trivial gravitational lensing effects. This paper aims at briefly overviewing the theoretical foundations of these effects, touching also some of the related phenomenology, both in General Relativity (GR) and alternative theories of gravity, hopefully providing some intuition and new insights for the underlying physics, which might be critical when testing the Kerr black hole hypothesis.Comment: 32 pages, 9 figures; Review paper in the General Relativity and Gravitation (GRG) Topical Collection "Testing the Kerr spacetime with gravitational-wave and electromagnetic observations" (Guest Editor: Emanuele Berti); v2: Typo corrected and two references adde

    A meta-regression analysis of benchmarking studies on water utilities market structure

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    This paper updates the literature on water utility benchmarking studies carried out worldwide, focusing on scale and scope economies. Using meta-regression analysis, the study investigates which variables from published studies influence these economies. Our analysis led to several conclusions. The results indicate that there is a higher probability of finding diseconomies of scale and scope in large utilities; however, only the results for scale economies are significant. Diseconomies of scale and scope are more likely to be found in publicly-owned utilities than when the ownership is mostly private; as would be expected, multi-utilities are more likely to have scale and scope economies.economies of scale; economies of scope; meta-regression analysis; water utilities
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