23,345 research outputs found

    The success factors for SMEs: Empirical evidence

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    This paper empirically analyzes the success factors for SMEs. Particularly, the paper intends to analyze if firm age, human resource costs, debt, venture capital funding, investment in innovation and productivity are success factors for SMEs. The effects were tested using static and dynamic panel data, on a data set of 200 Portuguese SMEs. The use of dynamic panel data is important in order to control for: endogeneity; time-invariant characteristics; possible collinearity between independent variables; effects from possible omission of independent variables; elimination of non-observable individual effects; and, the correct estimation of the relationship between the dependent variable in the previous and current periods. Our results reveal a positive impact on success of: human resource costs; investments in innovation; productivity; and, venture capital funding. We also confirm the negative impact of firm age and debt. Also, the results show evidence of persistence in success for the case of one of the success proxies used

    Tuning the metamagnetism of an antiferromagnetic metal

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    We describe a `disordered local moment' (DLM) first-principles electronic structure theory which demonstrates that tricritical metamagnetism can arise in an antiferromagnetic metal due to the dependence of local moment interactions on the magnetisation state. Itinerant electrons can therefore play a defining role in metamagnetism in the absence of large magnetic anisotropy. Our model is used to accurately predict the temperature dependence of the metamagnetic critical fields in CoMnSi-based alloys, explaining the sensitivity of metamagnetism to Mn-Mn separations and compositional variations found previously. We thus provide a finite-temperature framework for modelling and predicting new metamagnets of interest in applications such as magnetic cooling

    Final state interaction in D+Kπ+π+D^+\to K^-\pi^+\pi^+ with KπK\pi I=1/2 and 3/2 channels

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    The final state interaction contribution to D+D^+ decays is computed for the Kπ+π+K^-\pi^+\pi^+ channel within a light-front relativistic three-body model for the final state interaction. The rescattering process between the kaon and two pions in the decay channel is considered. The off-shell decay amplitude is a solution of a four-dimensional Bethe-Salpeter equation, which is decomposed in a Faddeev form. The projection onto the light-front of the coupled set of integral equations is performed via a quasi-potential approach. The S-wave KπK\pi interaction is introduced in the resonant isospin 1/21/2 and the non-resonant isospin 3/23/2 channels. The numerical solution of the light-front tridimensional inhomogeneous integral equations for the Faddeev components of the decay amplitude is performed perturbatively. The loop-expansion converges fast, and the three-loop contribution can be neglected in respect to the two-loop results for the practical application. The dependence on the model parameters in respect to the input amplitude at the partonic level is exploited and the phase found in the experimental analysis, is fitted with an appropriate choice of the real weights of the isospin components of the partonic amplitude. The data suggests a small mixture of total isospin 5/25/2 to the dominant 3/23/2 one. The modulus of the unsymmetrized decay amplitude, which presents a deep valley and a following increase for KπK\pi masses above 1.51.5 GeV, is fairly reproduced. This suggests the assignment of the quantum numbers 0+0^+ to the isospin 1/2 K(1630)K^*(1630) resonance

    Resonant x-ray scattering study on multiferroic BiMnO3

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    Resonant x-ray scattering is performed near the Mn K-absorption edge for an epitaxial thin film of BiMnO3. The azimuthal angle dependence of the resonant (003) peak (in monoclinic indices) is measured with different photon polarizations; for the σπ\sigma\to\pi' channel a 3-fold symmetric oscillation is observed in the intensity variation, while the σσ\sigma\to\sigma' scattering intensity remains constant. These features are accounted for in terms of the peculiar ordering of the manganese 3d orbitals in BiMnO3. It is demonstrated that the resonant peak persists up to 770 K with an anomaly around 440 K; these high and low temperatures coincide with the structural transition temperatures, seen in bulk, with and without a symmetry change, respectively. A possible relationship of the orbital order with the ferroelectricity of the system is discussed.Comment: 14 pages, 4 figure

    The impact of ancestral population size and incomplete lineage sorting on Bayesian estimation of species divergence times

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    MdR was supported by Biotechnology and Biological Sciences Research Council (UK) grant BB/J009709/1 awarded to ZY

    Queijos probióticos, alimentos lácteos nutritivos e funcionais.

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    bitstream/item/48476/1/Midia-Queijos-probioticos.pd

    Ácidos graxos: qual a relação com a saúde?

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    bitstream/item/48457/1/Midia-Acidos-graxos.pd

    Immunization and Aging: a Learning Process in the Immune Network

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    The immune system can be thought as a complex network of different interacting elements. A cellular automaton, defined in shape-space, was recently shown to exhibit self-regulation and complex behavior and is, therefore, a good candidate to model the immune system. Using this model to simulate a real immune system we find good agreement with recent experiments on mice. The model exhibits the experimentally observed refractory behavior of the immune system under multiple antigen presentations as well as loss of its plasticity caused by aging.Comment: 4 latex pages, 3 postscript figures attached. To be published in Physical Review Letters (Tentatively scheduled for 5th Oct. issue
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