Metapopulation dynamics of Primula vulgaris

Primula vulgaris Huds. shows a patchy distribution within its forest habitat. Each patch is viewed as a local population within a metapopulation. Patches are associated with gaps in the canopy and the foundation and extinction of local populations are coupled with forest canopy dynamics. This study analyses the system formed by local populations and their forest environment with the aim of understanding the factors that affect P. vulgaris metapopulation dynamics. Data was collected on the demography of local populations in patches in different light conditions, and on the changes in the canopy brought about by the forest regeneration cycle. These were combined to model the effect of forest disturbance regime and seed dispersal on metapopulation dynamics and overall abundance of P. vulgaris in the forest. The demography of local populations varied spatially in forest patches under different light conditions. Population growth rate (ƛ) was higher in brighter patches than in closed canopy patches. Population under closed canopy conditions may show negative growth rates which may result in eventual extinction. The system of forest patches is a dynamic one: canopy gaps are constantly opening and closing. Canopy closure occurs at an exponential rate and the structure of the forest (i.e., proportion of patches with different light conditions) depends largely on the disturbance regime (i.e., rate of gap creation).Simulation results showed that higher disturbance regimes produced higher metapopulation growth rate and higher overall P. vulgaris abundance in the forest. Long-distance seed dispersal reduced overall P. vulgaris abundance because it implied an amount of seed loss; however, it increased metapopulation growth rate, as it allowed the colonisation of newly-opened gaps. Under low disturbance regimes, P. vulgaris may form non-equilibrium metapopulations. Whether there is a balance between colonisations and extinctions depends on the effectiveness of seed dispersal in allowing the occupation of gaps

LA MERCANTILIZACIÓN DE LA EDUCACIÓN SUPERIOR

El presente trabajo tiene como objetivo identificar y analizar como la educación va cambiando su naturaleza esencialmente pública por una privada, y como lo anterior coloca a la educación superior como un producto dentro del mercado, donde la regla general es la libre competencia y la libre concurrencia. Los métodos dogmáticos, exegético y analítico fueron utilizados para el estudio de las diferentes doctrinas y legislación aplicables al caso, para obtener resultados y conclusiones que comprueban las problemáticas planteadas y que determinan que como consecuencia del crecimiento de la demanda de educación superior y ante la imposibilidad o incapacidad del Estado para prestar con eficiencia estos servicios, la iniciativa privada coadyuva y se beneficia obteniendo grandes ganancias económicas, provocando el mismo Estado una competencia desleal con las Instituciones de Educación Superior públicas

Factores implicados en la regulación del desarrollo de las vías del dolor.

En el presente trabajo de tesis doctoral hemos querido investigar aspectos de la regulación de las neuronas sensoriales periféricas que participan en la detección del dolor y, para ello, hemos estudiado la contribución de la neurotrofina BDNF y de la metaloproteasa MT-5 al desarrollo y mantenimiento de esta población sensorial de indudable inetrés biomédico. Los aspectos más destacables de los hallazgos pueden resumirse en: 1) hemos identificado por primera vez la dependencia trófica postnatal de neuronas nociceptivas de la neurotrofina BDNF, 2) la implicación de una metaloproteasa en la fisiología del dolor a través de acciones específicas en el crecimiento de las fibras nociceptivas y en su interacción con mastocitos de la piel. Ambos resultados son novedosos y contribuyen a una mejor comprensión de la percepción del dolor a nivel periférico

Splitting of separatrices in Hamiltonian systems with one and a half degrees of freedom

The splitting of separatrices for Hamiltonians with $1{1\over 2}$ degrees of freedom $$h(x,t /\varepsilon ) = h^{0}(x) + \mu \varepsilon ^{p} h^{1}(x,t /\varepsilon )$$ is measured. We assume that $h^{0}(x)= h^{0}(x_{1},x_{2})= x_{2}^{2}/2+V(x_{1})$ has a separatrix $x^{0}(t)$, $h^{1}(x,\theta )$ is $2\pi$-periodic in $\theta$, $\mu$ and $\varepsilon >0$ are independent small parameters, and $p\ge 0$. Under suitable conditions of meromorphicity for $x_{2}^{0}( u )$ and the perturbation $h^{1}(x^{0}( u ),\theta )$, the order $\ell$ of the perturbation on the separatrix is introduced, and it is proved that, for $p \ge \ell$, the splitting is exponentially small in $\varepsilon$, and is given in first order by the Melnikov function

Sal&dona

En este trabajo se va a presentar la plataforma digital Sal&dona (web y aplicación móvil) que aglutina ofertas de comercios y ofrece a los usuarios la posibilidad de donar los descuentos recibidos, promoviendo el consumo responsable. Ello se realizará mediante aquellos comercios que quieran promocionarse de una manera diferente y aumentar su fidelización de clientes ideológicamente

Do systemic collaboration and network governance matter? Living Labs beyond user-driven innovation

Despite the emergence and fast expansion of Living Lab (LL) around the world, little research has been conducted on the concept of LL from the perspective of both technological and social innovation and network governance. This paper critically reviews literature on the LL concept and other ‘innovation labs’ involving cross-border collaboration between private, public, and third sectors. Furthermore, we develop a framework outlining key analytical dimensions (context and aims, innovation types, stakeholders, partnership models, supporting, institutional environments, collaboration and network governance practices) and discuss findings from a study of an international sample of 120 LLs

Hacia una pedagogía de los valores en la Educación Superior

Se analiza el Proyecto Educativo como vía para desarrollar la educación en valores del estudiante de la Educación Superior en Cuba, lo cual puede generalizarse a otros contextos educativos. Se ofrecen las premisas y requerimientos para la concepción de un Proyecto Educativo científicamente fundamentado en las leyes y regularidades del proceso pedagógico En las bases psicopedagógicas para el diagnóstico se trata de precisar el lugar que ocupan los valores en la estructura de la personalidad y su relación con otras categorías psicológicas. Se concluye proponiendo que se tomen como base las esferas de actuación del estudiante universitario: las dimensiones curricular, sociopolítica y extensionista. El conteni-do esencial de las mismas se ha integrado en categorías que se podrán explorar mediante indicadores

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

Instability of high dimensional Hamiltonian systems: Multiple resonances do not impede diffusion

Abstract. We consider models given by Hamiltonians of the form H ( I;';p;q;t ; " ) = h ( I )+ n X j =1 1 2 p 2 j + V j ( q j ) + "Q ( I;';p;q;t ; " ) where I 2I R d ;' 2 T d , p;q 2 R n , t 2 T 1 . These are higher di- mensional analogues, both in the center and hyperbolic directions, of the models studied in [DLS03, DLS06a, GL06a, GL06b]. All these models present the large gap problem . We show that, for 0 < " 1, under regularity and explicit non- degeneracy conditions on the model, there are orbits whose action variables I perform rather arbitrary excursions in a domain of size O (1). This domain includes resonance lines and, hence, large gaps among d -dimensional KAM tori. The method of proof follows closely the strategy of [DLS03, DLS06a]. The main new phenomenon that appears when the di- mension d of the center directions is larger than one, is the exis- tence of multiple resonances. We show that, since these multiple resonances happen in sets of codimension greater than one in the space of actions I , they can be contoured. This corresponds to the mechanism called di usion across resonances in the Physics literature. The present paper, however, di ers substantially from [DLS03, DLS06a]. On the technical details of the proofs, we have taken advantage of the theory of the scattering map [DLS08], not avail- able when the above papers were written. We have analyzed the conditions imposed on the resonances in more detail. More precisely, we have found that there is a simple condition on the Melnikov potential which allows us to conclude that the res- onances are crossed. In particular, this condition does not depend on the resonances. So that the results are new even when applied to the models in [DLS03, DLS06a]Preprin