Qualitative social differentiation in tertiary education in Spain

[cat] En aquest treball, s'estudia si la hip��tesi de la desigualtat efectivament mantinguda ���effectively maintained inequality��� es cumpleix a Espanya. Es postula que en les transicions terci��ries a Espanya, les influ��ncies dels pares no es manifesten tant a trav��s de la probabilitat de fer la transici��, sin�� m��s aviat a trav��s de les difer��ncies qualitatives associades a aquesta transici�� en termes de les qualitats dels programes educatius. Analitzem dues caracter��stiques qualitatives dels estudis universitaris: la durada del programa i el seu prestigi acad��mic. Identifiquem per a quins individus la influ��ncia parental ��s m��s important en cada cas.

Growth factor- and cytokine-driven pathways governing liver stemness and differentiation.

Liver is unique in its capacity to regenerate in response to injury or tissue loss. Hepatocytes and other liver cells are able to proliferate and repopulate the liver. However, when this response is impaired, the contribution of hepatic progenitors becomes very relevant. Here, we present an update of recent studies on growth factors and cytokine-driven intracellular pathways that govern liver stem/progenitor cell expansion and differentiation, and the relevance of these signals in liver development, regeneration and carcinogenesis. Tyrosine kinase receptor signaling, in particular, c-Met, epidermal growth factor receptors or fibroblast growth factor receptors, contribute to proliferation, survival and differentiation of liver stem/progenitor cells. Different evidence suggests a dual role for the transforming growth factor (TGF)-�� signaling pathway in liver stemness and differentiation. On the one hand, TGF-�� mediates progression of differentiation from a progenitor stage, but on the other hand, it contributes to the expansion of liver stem cells. Hedgehog family ligands are necessary to promote hepatoblast proliferation but need to be shut off to permit subsequent hepatoblast differentiation. In the same line, the Wnt family and ��-catenin/T-cell factor pathway is clearly involved in the maintenance of liver stemness phenotype, and its repression is necessary for liver differentiation during development. Collectively, data indicate that liver stem/progenitor cells follow their own rules and regulations. The same signals that are essential for their activation, expansion and differentiation are good candidates to contribute, under adequate conditions, to the paradigm of transformation from a pro-regenerative to a pro-tumorigenic role. From a clinical perspective, this is a fundamental issue for liver stem/progenitor cell-based therapies.

Ancient DNA of the extinct Lava shearwater (Puffinus olsoni) from the Canary Islands reveals incipient differentiation within the P. puffinus complex

The loss of species during the Holocene was, dramatically more important on islands than on continents. Seabirds from islands are very vulnerable to human-induced alterations such as habitat destruction, hunting and exotic predators. For example, in the genus Puffinus (family Procellariidae) the extinction of at least five species has been recorded during the Holocene, two of them coming from the Canary Islands.

Niche Differentiation and Fine-Scale Projections for Argentine Ants Based on Remotely Sensed Data

Modeling ecological niches of species is a promising approach for predicting the geographic potential of invasive species in new environments. Argentine ants (Linepithema humile) rank among the most successful invasive species: native to South America, they have invaded broad areas worldwide. Despite their widespread success, little is known about what makes an area susceptible - or not - to invasion. Here, we use a genetic algorithm approach to ecological niche modeling based on high-resolution remote-sensing data to examine the roles of niche similarity and difference in predicting invasions by this species. Our comparisons support a picture of general conservatism of the species' ecological characteristics, in spite of distinct geographic and community contexts

Biochemical differentiation between Ophidion Barbatum and o. Rochei (Pisces, Ophidiidae)

El g��nere Ophidion esta representat al Mediterrani per dues esp��cies, 0. barbatum L. i O.rochei M��ller. S��n dues esp��cies molt similars en aspecte i dif��cils d'identificar nom��s apartir dels seus car��cters morfol��gics externs. El treball descriu en primer lloc, i a partir de dades obtingudes per t��cniques electrofor��tiques, alguns marcadors bioqu��mics que permetendiferenciar les dues esp��cies. En segon lloc, i a partir del c��lcul de la 'Dist��ncia Gen��ticade Nei', es fa una estimaci�� del temps de diverg��ncia entre O. barbatum i 0. rochei