Persistence and ability in the innovation decisions

The main concern of this paper is to analyse the complementarities between the decisions to carry out both product and process innovations. We also try to identify the main determinants of the innovation activity as well as to separate the experience effect of the firm (capacities, routines as organization) from the experience effect of the manager (skills, abilities). It has been common when facing the study of technological change, to consider innovation as a homogeneous activity. The main analyses have focused on the determinants of such activity trying to explain decisions, counts or R and D expenses in the context of a unique activity. Several recent works, however, are worried about the possibility of analysing innovation distinguishing among different types according to the final purpose of this activity. We focus on two different decisions, product and process innovations, using typical discrete choice specifications (univariate and bivariate models) and also binary choice models with heterogeneity. Among the results, we find complementary but asymmetric effects concerning both decisions in static models even controlling heterogeneity. We also test whether the persistence in conducting innovation activities matter. We do so in an extensive database that provides information about manufacturing firms. Our results point towards the importance of both ability of the manager (unobserved heterogeneity) and experience of the firm (dynamics in the equation indicator)

PERSISTENCE AND ABILITY IN THE INNOVATION DECISIONS

The main concern of this paper is to analyse the complementarities between the decisions to carry out both product and process innovations. We also try to identify the main determinants of the innovation activity as well as to separate the experience effect of the firm (capacities, routines as organization) from the experience effect of the manager (skills, abilities). It has been common when facing the study of technological change, to consider innovation as a homogeneous activity. The main analyses have focused on the determinants of such activity trying to explain decisions, counts or R&D expenses in the context of a unique activity. Several recent works, however, are worried about the possibility of analysing innovation distinguishing among different types according to the final purpose of this activity. We focus on two different decisions, product and process innovations, using typical discrete choice specifications (univariate and bivariate models) and also binary choice models with heterogeneity. Among the results, we find complementary but asymmetric effects concerning both decisions in static models even controlling heterogeneity. We also test whether the persistence in conducting innovation activities matter. We do so in an extensive database that provides information about manufacturing firms. Our results point towards the importance of both ability of the manager (unobserved heterogeneity) and experience of the firm (dynamics in the equation indicator).

VNUML vs GNS3 en el desarrollo de laboratorios de redes virtuales

El aprendizaje práctico de redes de computadores es reconocido como un proceso crítico que permite a los estudiantes consolidar los conceptos introducidos en las lecciones teóricas. En este sentido, las tecnologías de virtualización están adquiriendo gran relevancia debido a que permiten desarrollar laboratorios de redes de computadores con un reducido coste de despliegue y gestión. Este artículo presenta un análisis comparativo entre GNS3 y VNUML, que son herramientas de virtualización open-source que han sido empleadas para el desarrollo de laboratorios de red virtuales para llevar a cabo el proceso de enseñanza-aprendizaje en las asignaturas Arquitectura de Redes y Arquitectura de Redes Avanzadas del Grado en Ingeniería Informática impartido en la Universidad de Murcia. El estudio presenta las principales ventajas y/o deficiencias de cada herramienta tanto para profesores como alumnos y se identifican los escenarios en los que parece más adecuada su utilización.SUMMARY -- The practical learning of computer networks is known to be a critical process in order to allow students to consolidate the concepts introduced in theoretical lessons. In this sense, virtualization technologies are becoming popular since they allow to set up a computer network laboratory with a reduced deployment and management cost. This paper presents a comparative analysis performed between GNS3 and VNUML, which are open-source tools for virtualization that have been used for developing virtual network laboratories that support the teaching-learning process in the Networks Architecture and Advanced Networks Architecture subjects of the Computer Engineering degree at the University of Murcia. The study presents the main advantages and/or deficiencies of each tool not only for professors but also for students and identifies the scenarios where the use of each tool seems to be more appropriate.Peer Reviewe

Splitting of separatrices in Hamiltonian systems and symplectic maps

Poincar\'e, Melnikov and Arnol'd introduced the standard method for measuring the splitting of separatrices of Hamiltonian systems. It is based on the study of the zeros of the so-called Melnikov integral, a vectorial function for three or more degrees of freedom, that gives the first-order behavior. In the most interesting cases, it turns out that the splitting is exponentially small with respect of the parameter of the perturbation, and that means that the remainder has to be bounded very carefully. The mechanism for obtaining rigorously this exponentially small splitting for the one and a half degrees of freedom Hamiltonians is reviewed, and the main ideas for its generalization to more degrees of freedom are presented. Concerning symplectic maps, the Melnikov function is not an integral anymore, but an infinite sum. Nevertheless, for meromorphic perturbations of $2D$-area preserving maps, the Melnikov function turns out to be an elliptic function, and moreover can be evaluated via residues. Furthermore, general results on non-integrability can be provided. For instance, the elliptic billiard turns out to be non-integrable when perturbed by any non-trivial entire perturbation. For more degrees of freedom, using variational arguments, the Melnikov vectorial function for a symplectic map can be deduced from a scalar function (the Melnikov potential), and the splitting of separatrices associated to hyperbolic points can also be easily detected in several situations, for instance for generalized standard maps

Stability of the phase motion in race-track microtrons

We model the phase oscillations of electrons in race-track microtrons by means of an area preserving map with a fixed point at the origin, which represents the synchronous trajectory of a reference particle in the beam. We study the nonlinear stability of the origin in terms of the synchronous phase —the phase of the synchronous particle at the injection. We estimate the size and shape of the stability domain around the origin, whose main connected component is enclosed by an invariant curve. We describe the evolution of the stability domain as the synchronous phase varies. We also clarify the role of the stable and unstable invariant curves of some hyperbolic (fixed or periodic) points.Peer ReviewedPostprint (author's final draft

Bent-core liquid crystalline cyanostilbenes : fluorescence switching and thermochromism

The authors from ICMA greatly appreciate financial support from the Spanish Government (MINECO-FEDER project MAT2012-38538-C03-01), the Aragon's Government and FSE (project E04) and the Jae PreDoc-CSIC (M. M.-A.) fellowship program.Fluorescent bent-core molecules, bearing one or two cyanostilbene units in the lateral structure and different positions of the cyano group (α- or β-isomers), are described with the aim of modulating the molecular packing and fluorescence properties. These compounds give rise to a variety of crystal polymorphs and bent-core liquid crystalline phases (SmCP, Colr and B6), offering the unique chance to study the fluorescence properties of the cyanostilbene structure in different phases. Experimental and computational studies elucidate geometrical and electronic properties of these bent-core structures but especially the fluorescence properties (spectral positions, quantum yields and decay curves), in a detailed comparison between diluted solutions, in dichloromethane (DCM) or poly(methylmethacrylate) (PMMA), and condensed phases. Quantum yields as high as 70% have been obtained in some diluted solutions (PMMA) and condensed phases. Remarkably, the quantum yield values depend on the position of the cyano group, being higher for β- than for the α-isomers due to the higher radiative rates and lower non-radiative rates of the former. The photophysical characterization in the condensed phase focuses on RT studies with solid samples and different processing, and show that, upon aggregation, interactions between the cyanostilbene groups result in changes of the emission spectra and dynamics compared to the diluted systems in DCM and PMMA, giving rise to H-aggregations of varying strength. Furthermore, the compounds exhibit thermochromism, showing a green-yellow fluorescence in the pristine crystalline phase that changes to blue on heating to the liquid crystal phase. This journal isPostprintPeer reviewe

FIRST REVIEW OF THE LYNCODONTINI MATERIAL (MUSTELIDAE, CARNIVORA, MAMMALIA) FROM THE LOWER PLEISTOCENE ARCHAEO-PALAEONTOLOGICAL SITES OF ORCE (SOUTHEASTERN SPAIN)

Two archaeo-palaeontological Lower Pleistocene sites of Orce (Baza Basin, SE Spain), Fuente Nueva 3 (1.3 Ma) and Barranco León (1.4 Ma), preserve some of the earliest evidences of human presence in the European continent. During the 2013 field season, a small Lyncodontini mustelid mandible was found at Fuente Nueva-3. This finding was accompanied by a lower canine (c1), also from the same site, and a lower fourth premolar (p4) from Barranco León. Here, we report on the morphological and biometrical study of these materials, in comparison to other Eurasian Pliocene-Pleistocene species of the tribe Lyncodontini. The analyses revealed an affinity between the taxon from Fuente Nueva-3 and Barranco León with the small-sized European species Martellictis ardea (Gervais, 1848-1852), allowing us to ascribe the described material to the latter species. The presence of M. ardea in the sites of Orce is the southernmost occurrence of the species in the Iberian Peninsula and an important finding in the scarce fossil record of Lyncodontini in Europe

ObRa and ObRe are differentially expressed in adipose tissue in aged food-restricted rats: Effects on circulating soluble leptin receptor levels

Copyright (2005) The Endocrine Society .The paper can be found at the following URL on the website http://endo.endojournals.org