Our Lady of Guadalupe: Sources in English

According to tradition, the Virgin of Guadalupe appeared to Juan Diego, an Indian, on a hill near the outskirts of Mexico City on a December morning in 1531. Before the Conquest, the site of her apparition, Tepeyac, had been a sacred place dedicated to the Aztec goddess, Tonantzin. Her image, imprinted on Juan Diego's mantle, was one of a brown-skinned madonna with pre-Columbian vestiges, and struck a chord with her early supplicants. A cult soon developed around "La Morenita." She was adopted as a symbol of Mexican nationalism, and has become a rallying point for political and social movements from the Mexican countryside of the insurgents to the fields of California's farmworkers. To her devotees, La Virgen de Guadalupe invokes faith, hope, and compassion; she embraces the cause of the poor, the ignored, the voiceless, the oppressed. In short, La Reina de México and Emperatriz de las Américas, as she is often referred to, has left a profound impact of the religious and cultural life of Mexicans and Mexican Americans.UT Librarie

An extension problem for the CR fractional Laplacian

We show that the conformally invariant fractional powers of the sub-Laplacian on the Heisenberg group are given in terms of the scattering operator for an extension problem to the Siegel upper halfspace. Remarkably, this extension problem is different from the one studied, among others, by Caffarelli and Silvestre.Comment: 33 pages. arXiv admin note: text overlap with arXiv:0709.1103 by other author

No hay cama pa tanta gente

La nación Colombiana está pasando por una de sus peores crisis en cuanto a su sistema de salud, casi nunca hemos visto los problemas que estamos afrontando en el tiempo actual, había problemas de cobertura y servicio, pero de quiebra general nunca

No hay cama pa tanta gente

La nación Colombiana está pasando por una de sus peores crisis en cuanto a su sistema de salud, casi nunca hemos visto los problemas que estamos afrontando en el tiempo actual, había problemas de cobertura y servicio, pero de quiebra general nunca

Precision of the Dpp gradient

Morphogen concentration gradients provide positional information by activating target genes in a concentration-dependent manner. Recent reports show that the gradient of the syncytial morphogen Bicoid seems to provide precise positional information to determine target gene domains. For secreted morphogenetic ligands, the precision of the gradients, the signal transduction and the reliability of target gene expression domains have not been studied. Here we investigate these issues for the TGF-β-type morphogen Dpp. We first studied theoretically how cell-to-cell variability in the source, the target tissue, or both, contribute to the variations of the gradient. Fluctuations in the source and target generate a local maximum of precision at a finite distance to the source. We then determined experimentally in the wing epithelium: (1) the precision of the Dpp concentration gradient; (2) the precision of the Dpp signaling activity profile; and (3) the precision of activation of the Dpp target gene spalt. As captured by our theoretical description, the Dpp gradient provides positional information with a maximal precision a few cells away from the source. This maximal precision corresponds to a positional uncertainly of about a single cell diameter. The precision of the Dpp gradient accounts for the precision of the spalt expression range, implying that Dpp can act as a morphogen to coarsely determine the expression pattern of target genes

Critical Point in Self-Organized Tissue Growth

We present a theory of pattern formation in growing domains inspired by biological examples of tissue development. Gradients of signaling molecules regulate growth, while growth changes these graded chemical patterns by dilution and advection. We identify a critical point of this feedback dynamics, which is characterized by spatially homogeneous growth and proportional scaling of patterns with tissue length. We apply this theory to the biological model system of the developing wing of the fruit fly \textit{Drosophila melanogaster} and quantitatively identify signatures of the critical point.Comment: 5 pages, 3 figure

Participation in higher education: Barriers and opportunities for non-traditional students in higher education in Germany and Spain

This paper explores participation in higher education in Germany and Spain through two case studies from the RANLHE project. There is one case in each national context (Germany and Spain) based on biographical interviews undertaken between 2008 and 2010. Social, economic and cultural dimensions are explored in order to better understand the German and Spanish contexts. In addition, we look at the comparison of the two cultural and institutional contexts, searching for a more complex description of the processes related to access, retention, completion and learning in higher education from a European and transnational perspective. These issues are connected to social challenges regarding inequalities and social class

Eliminación de cromo utilizando humedales de flujo sub-superficial horizontal

Los humedales se incluyen entre los llamados sistemasnaturales de tratamiento, donde los contaminantes presentesen las aguas residuales son removidos a través de procesos físicos, químicos y biológicos de forma natural.Las Tenerías son industrias con grandes volúmenes deaguas residuales contaminadas. En Cuba la tenería deCaibarien de la provincia de Villa Clara no cuenta con unsistema óptimo de tratamiento para sus residuales, por loque el vertido del mismo al medio es un problema de consideración, máxime si tenemos en cuenta la presencia desulfuros y metales pesados como el Cromo.En este trabajo se construye a escala de laboratorioun humedalartificial de flujo sub-superficial para su evaluación en la remoción de cromo de las aguas residuales de la industria, obteniéndose una eficiencia entre el 88 % y el 92%. Este es el elemento de mayor interés en el trabajo, ya que es conocido el daño que representa para la salud humana y el medio ambiente al ser este un elemento persistente