28,144 research outputs found

    How Has the Portuguese Innovation Capability Evolved? Estimating a Time Series of the Stock of Technological Knowledge, 1960-2001

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    The importance of promoting innovation has been elevated up to a status of official standard since the Lisbon European Summit in 2000. Here research and development (R&D) was singled out as an essential element of the foundation on which innovation could be built. R&D has been a growing area of investigation namely at level of firms micro studies aimed at uncovering firms’ innovation capability. At the macro level, the relevance of R&D for countries’ innovation capability has been, in a dynamic perspective, more often presumed rather than effectively tested. This latter limitation is, to a large extent, explained by the paucity of aggregated continuous time series on innovation indicators specifically those based on R&D expenditures. This paper aims at filling this gap by providing an estimate of the Portuguese innovation capability over the two last four decades based on the accumulated R&D efforts. Such indicator, albeit preliminary, will desirably endorse new investigation on the Portuguese catching-up process and, in this way, might inform present and future public programs related to R&D policies in particular and innovation policies in general.Innovation; R&D expenditures; measurement, economic growth

    Universality of trap models in the ergodic time scale

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    Consider a sequence of possibly random graphs GN=(VN,EN)G_N=(V_N, E_N), N≄1N\ge 1, whose vertices's have i.i.d. weights {WxN:x∈VN}\{W^N_x : x\in V_N\} with a distribution belonging to the basin of attraction of an α\alpha-stable law, 0<α<10<\alpha<1. Let XtNX^N_t, t≄0t \ge 0, be a continuous time simple random walk on GNG_N which waits a \emph{mean} WxNW^N_x exponential time at each vertex xx. Under considerably general hypotheses, we prove that in the ergodic time scale this trap model converges in an appropriate topology to a KK-process. We apply this result to a class of graphs which includes the hypercube, the dd-dimensional torus, d≄2d\ge 2, random dd-regular graphs and the largest component of super-critical Erd\"os-R\'enyi random graphs

    An empirical analysis of structural models of corporate debt pricing

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    This paper tests empirically the performance of three structural models of corporate bond pricing, namely Merton (1974), Leland (1994) and Fan and Sundaresan (2000). While the first two models overestimate bond prices, the Fan and Sundaresan model reveals an extremely good performance. When considering the prediction of credit spreads, the three models under-estimate market spreads but, again, Fan and Sundaresan has a better performance. We find rating, maturity and asset volatility effects in the prediction power, as the models under-estimate less the spreads of riskier firms and of bonds with better rating quality and longer maturity. Moreover, our results reveal the existence of a new industry effect. Spread errors are systematically related to some bond- and firm-specific variables, as well as term structure variables.structural models, corporate debt valuation, empirical credit spreads

    FDI, income inequality and poverty : a time series analysis of Portugal, 1973–2016

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    Using time series data for Portugal between 1973 and 2016, this paper examines to what extent, inward FDI contributes to income inequality and poverty in the long-run. It was found that increased flows of inward FDI are associated with a less unequal income distribution and lower poverty rates. The results further suggest that, in the Portuguese case there is mutual causality between inward FDI and poverty in the long run, i.e., FDI significantly reduces poverty, and lower levels of poverty lead to higher inward FDI flows. In the case of inequality, the evidence shows that FDI does not contribute to higher (or lower) income inequality. Instead, more unequal income distributions significantly and negatively impact on inward FDI in the long run. Finally, human capital emerged as a key determinant to mitigate income inequality and circumvent poverty, contributing, indirectly, to fostering additional FDI inflows. Such results call for integrated public policy interventions that emphasize social and institu- tional dimensions.info:eu-repo/semantics/publishedVersio

    Lepton masses and mixings in orbifold models with three Higgs families

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    We analyse the phenomenological viability of heterotic Z(3) orbifolds with two Wilson lines, which naturally predict three supersymmetric families of matter and Higgs fields. Given that these models can accommodate realistic scenarios for the quark sector avoiding potentially dangerous flavour-changing neutral currents, we now address the leptonic sector, finding that viable orbifold configurations can in principle be obtained. In particular,it is possible to accomodate present data on charged lepton masses, while avoiding conflict with lepton flavour-violating decays. Concerning the generation of neutrino masses and mixings, we find that Z(3) orbifolds offer several interesting possibilities.Comment: 28 pages, 11 figures. References adde

    The importance of Intermediaries organizations in international R&D cooperation: an empirical multivariate study across Europe

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    Despite the large number of publications related to business cooperation in R&D and the wide perception of the importance of intermediary institutions in the R&D cooperation process, empirical studies on its role are scarce, scattered and fragmented. Moreover, the academic work developed in this area is basically of a theoretical nature, whereas the international perspective of R&D cooperation is seldom approached. Departing from a unique database that includes 473 R&D cooperation projects developed within the 6th Framework Programme, involving firms and intermediaries from all European Union countries, this paper gauges the determinants of the importance attached to Intermediaries, through a direct survey to the organizations involved. Based on an estimation of the multivariate model, this study demonstrates that the importance given to Intermediaries depends more on project features than on the characteristics of the participating organizations. In particular, the nationality of participating organizations and the promoter emerged with a strong explanatory power: ceteris paribus, projects with at least one participant from the United Kingdom tend to assign greater importance to intermediaries in international R&D cooperation. Unambiguously, results evidence that the innovating capacity of an organization emerges (both positively and significantly) associated with a greater importance attached to Intermediaries.R&D Cooperation; Intermediaries; International projects; Europe

    Spontaneous CP Violation in the Next-to-Minimal Supersymmetric Standard Model Revisited

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    We re-examine spontaneous CP violation at the tree level in the context of the next-to-minimal supersymmetric standard model (NMSSM) with two Higgs doublets and a gauge singlet field. We analyse the most general Higgs potential without a discrete Z_3 symmetry, and derive an upper bound on the mass of the lightest neutral Higgs boson consistent with present experimental data. We investigate, in particular, its dependence on the admixture and CP-violating phase of the gauge singlet field, as well as on tan(beta). To assess the viability of the spontaneous CP violation scenario, we estimate epsilon_K by applying the mass insertion approximation. We find that a non-trivial flavour structure in the soft-breaking A terms is required to account for the observed CP violation in the neutral kaon sector. Furthermore, combining the minimisation conditions for spontaneous CP violation with the constraints coming from K0-K0bar mixing, we find that the upper bound on the lightest Higgs-boson mass becomes stronger. We also point out that the electric dipole moments of electron and neutron are a serious challenge for SUSY models with spontaneous CP violation.Comment: 19 pages, LaTeX2e, 5 figures; matches the published versio
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