La descentralización de los servicios de educación en Colombia

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La descentralización de los servicios de salud en Colombia

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La descentralización de los servicios de educación y salud en Colombia

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El libre desarrollo de la personalidad en los flujos migratorios

[ES] El análisis sobre la figura del paternalismo legal, en contraposición al libre desarrollo de la personalidad, con especial incidencia en materia de extranjería, más concretamente, en la figura del inmigrante, nos lleva a orientar el estudio de esta figura sobre el fenómeno de la inmigración por razones de variada índole. A nadie le resulta extraño el revuelo social y político que está levantando este asunto .La inmigración, aparte de ser un tema que afecta a diversos aspectos, hay que analizarla en todas las facetas en las que repercute: la limitación que supone al libre desarrollo de la personalidad de un individuo que decide trasladarse a un lugar diferente al de su nacionalidad como vía para desarrollar en libertad su personalidad, también como hecho social, jurídico, económico y cultural, que suscita problemas poblacionales de discriminación, integración y xenofobia, y muchos otros aspectos.

Eco-evolutionary Dynamics of Individual-Based Food Webs

The past decade has seen the rise of high resolution datasets. One of the main surprises of analysing such data has been the discovery of a large genetic, phenotypic and behavioural variation and heterogeneous metabolic rates among individuals within natural populations. A parallel discovery from theory and experiments has shown a strong temporal convergence between evolutionary and ecological dynamics, but a general framework to analyse from individual-level processes the convergence between ecological and evolutionary dynamics and its implications for patterns of biodiversity in food webs has been particularly lacking. Here, as a first approximation to take into account intraspecific variability and the convergence between the ecological and evolutionary dynamics in large food webs, we develop a model from population genomics and microevolutionary processes that uses sexual reproduction, genetic-distance-based speciation and trophic interactions. We confront the model with the prey consumption per individual predator, species-level connectance and prey–predator diversity in several environmental situations using a large food web with approximately 25,000 sampled prey and predator individuals. We show higher than expected diversity of abundant species in heterogeneous environmental conditions and strong deviations from the observed distribution of individual prey consumption (i.e. individual connectivity per predator) in all the environmental conditions. The observed large variance in individual prey consumption regardless of the environmental variability collapsed species-level connectance after small increases in sampling effort. These results suggest (1) intraspecific variance in prey–predator interactions has a strong effect on the macroscopic properties of food webs and (2) intraspecific variance is a potential driver regulating the speed of the convergence between ecological and evolutionary dynamics in species-rich food webs. These results also suggest that genetic–ecological drift driven by sexual reproduction, equal feeding rate among predator individuals, mutations and genetic-distance-based speciation can be used as a neutral food web dynamics test to detect the ecological and microevolutionary processes underlying the observed patterns of individual and species-based food webs at local and macroecological scales.

Chapter Six – Individual Trait Variation and Diversity in Food Webs

In recent years, there has been a renewed interest in the ecological consequences of individual trait variation within populations. Given that individual variability arises from evolutionary dynamics, to fully understand eco-evolutionary feedback loops, we need to pay special attention to how standing trait variability affects ecological dynamics. There is mounting empirical evidence that intra-specific phenotypic variation can exceed species-level means, but theoretical models of multi-trophic species coexistence typically neglect individual-level trait variability. What is needed are multispecies datasets that are resolved at the individual level that can be used to discriminate among alternative models of resource selection and species coexistence in food webs. Here, using one the largest individual-based datasets of a food web compiled to date, along with an individual trait-based stochastic model that incorporates Approximate Bayesian computation methods, we document intra-population variation in the strength of prey selection by different classes or predator phenotypes which could potentially alter the diversity and coexistence patterns of food webs. In particular, we found that strongly connected individual predators preferentially consumed common prey, whereas weakly connected predators preferentially selected rare prey. Such patterns suggest that food web diversity may be governed by the distribution of predator connectivity and individual trait variation in prey selection. We discuss the consequences of intra-specific variation in prey selection to assess fitness differences among predator classes (or phenotypes) and track longer term food web patterns of coexistence accounting for several phenotypes within each prey and predator species.

En defensa de la forma : Poesía social y realismo en la obra temprana de Juan L. Ortiz

La obra poética de Juan L. Ortiz resuelve de una manera inédita en la literatura argentina la tensión que existe entre política y poesía. Su relación con el Partido Comunista, con ciertos escritores del grupo de Boedo y luego, centralmente, con González Tuñón, allá por la década de 1930-1940, no redundan en una adaptación de su obra a los postulados determinantes del realismo. Por partida doble, diremos, Ortiz rechaza al realismo. En un primer momento, frente al realismo de Boedo decide "envainar la espada", teniendo a la vista los resultados estéticos de aquel programa. Luego, de cara a la evolución que suponía la idea del realismo en Tuñón hacia mediados de 1930, opta por mantener un ritmo propio y reflejar la enorme crisis política que se vivía (con España como epicentro) sin quebrar su forma personal del decir. Una voz tendiente a la sutileza, a resaltar el aspecto musical del lenguaje en relación con el paisaje y loalusivo. Lo que lo hace original, entonces, es justamente el hecho de colocar la cuestión social y política dentro de esa intimidad, gracias a una concepción dialéctica de su poesía, que está en la base de su programa estético