23,345 research outputs found
The success factors for SMEs: Empirical evidence
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
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 with I=1/2 and 3/2 channels
The final state interaction contribution to decays is computed for the
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
interaction is introduced in the resonant isospin and the
non-resonant isospin 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 to the dominant
one. The modulus of the unsymmetrized decay amplitude, which presents a deep
valley and a following increase for masses above GeV, is fairly
reproduced. This suggests the assignment of the quantum numbers to the
isospin 1/2 resonance
Resonant x-ray scattering study on multiferroic BiMnO3
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 channel a 3-fold symmetric oscillation
is observed in the intensity variation, while the 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
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.
bitstream/item/48476/1/Midia-Queijos-probioticos.pd
Immunization and Aging: a Learning Process in the Immune Network
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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