Novis Teófilo, El Chaco en imágenes (1887)

El libro que Isabelle Combès pone en nuestras manos corre el riesgo de convertirse en una fuente iconográfica “clásica” para abordar la historia del Chaco y sus habitantes a fines del siglo xix, como lo fue hace más de veinte años el Álbum fotográfico de las misiones franciscanas [1898] elaborado por el franciscano Doroteo Giannecchini con el material fotográfico producido por Vincenzo Mascio, editado casi un siglo después por otro franciscano, Lorenzo Calzavarini (1995). Pero, a diferencia d..

Educación basada en competencias en línea : Lecciones de EE.UU. para América Latina

Hay una creciente preocupación en los Estados Unidos y América Latina por mejorar la relevancia de la educación superior y mantener los costos bajo control. Esta realidad ha llevado a países del hemisferio a experimentar con programas alternativos como, por ejemplo, los MOOCs (Massive Open Online Courses), cursos en línea dirigidos masivamente a un amplio número de personas. Sin embargo, como explicamos más adelante, estas alternativas muchas veces sufren las mismas limitaciones que los programas tradicionales. En los Estados Unidos, diversos factores están poniendo presión en los sistemas de educación superior: los costos de matrícula han aumentado dramáticamente; los préstamos estudiantiles exceden el trillón de dólares (Edvisors, 2015); los costos para las instituciones proveedoras de servicios educativos han aumentado con el fin de mantener su competitividad en el mercado; y se espera que la ayuda financiera que ofrecen las entidades gubernamentales disminuya en los próximos años (Weise & Christensen, 2014). Estas presiones se empiezan a manifestar también en países de América Latina. Por ejemplo, en Chile el alto endeudamiento de los estudiantes terciarios motivó una ola de protestas estudiantiles y una reforma educativa significativa. Las presiones financieras se empezarán a sentir más en otros países a medida que se expande la cobertura educativa. En este contexto, la educación basada en competencias en línea (EBCEL) ha surgido como una opción viable para muchos individuos que quieren avanzar su carrera profesional. Esta nota técnica analiza la experiencia de los Estados Unidos con este tipo de “innovación disruptiva” en la educación post-secundaria. Ofrece definiciones sobre la educación basada en competencias en línea y discute su importancia; evaluamos las limitaciones de los programas universitarios tradicionales y la aparición de los programas en línea; examinamos las principales características de la EBCEL; y analizamos el impacto que han tenido algunos de estos programas en universidades estadounidenses

CONTAGION OF US SUBPRIME MORTGAGE CRISIS TO COLOMBIAN ECONOMY: MEASURED BY FINANCIAL MARKET DATA

The long-horizon event study methodology is used to document the severe impact of the US subprime mortgage crisis on the Colombian economy. The estimated parameter of a constantmean return model is used to derive the “abnormal return” on the market portfolios of Colombia over its selected event window. Analyses of the results reveal that the US subprime mortgage crisis negatively affected both the Colombian and the US equity markets almost identically in terms of cumulative percentage reductions and timing. Statistic testing results seem to support the qualitative observation. This phenomenon can be attributable to the recent multilateral and regional trade agreements that increase the flow of trade and foreign direct investment to Colombia.El estudio metodológico de horizonte largo es usado para documentar el impacto severo de la crisis de la finca raíz de Estados Unidos en la Economía Colombiana. El parámetro estimado de la constante del retorno del modelo es usado para derivar el retorno anormal en el mercado de portafolios sobre su selección de la ventana de evento. Análisis de estos resultados revelan que la crisis de la finca raíz en Estados Unidos afectó negativamente ambos mercados de acciones en Estados Unidos y Colombia casi idénticamente en términos de reducción de porcentaje cumulativo y tiempo. Resultados de pruebas estadísticas parecen soportar la observación. Este fenómeno puede ser atribuido a los recientes acuerdos de comercio multilaterales y regionales que incrementan el flujo de comercio e inversión extranjera directa a Colombia

Os nacionalismos ibéricos nos estudos sobre o romanceiro tradicional

1 As bases do problema. – 2 Contornos do(s) nacionalismo(s) ibérico(s). – 2.1 O caso português. – 2.2 O caso catalão. – 2.3 O caso galego. – 3 O comparatismo como metodologia. – 4 Que pan-hispanismo? Alguns equívocos e desconhecimentos. – 4.1 Fontes documentais e estudos críticos. – 4.2 Na atividade editorial. – 5 Palavras finaisinfo:eu-repo/semantics/publishedVersio

Substrate promiscuity of inositol 1,4,5-trisphosphate kinase driven by structurally-modified ligands and active site plasticity

D-myo-inositol 1,4,5-trisphosphate (InsP3) is a fundamental second messenger in cellular Ca2+ mobilization. InsP3 3-kinase, a highly specific enzyme binding InsP3 in just one mode, phosphorylates InsP3 specifically at its secondary 3-hydroxyl group to generate a tetrakisphosphate. Using a chemical biology approach with both synthetised and established ligands, combining synthesis, crystallography, computational docking, HPLC and fluorescence polarization binding assays using fluorescently-tagged InsP3, we have surveyed the limits of InsP3 3-kinase ligand specificity and uncovered surprisingly unforeseen biosynthetic capacity. Structurally-modified ligands exploit active site plasticity generating a helix-tilt. These facilitated uncovering of unexpected substrates phosphorylated at a surrogate extended primary hydroxyl at the inositol pseudo 3-position, applicable even to carbohydrate-based substrates. Crystallization experiments designed to allow reactions to proceed in situ facilitated unequivocal characterization of the atypical tetrakisphosphate products. In summary, we define features of InsP3 3-kinase plasticity and substrate tolerance that may be more widely exploitable

Migration and "Low-Skilled" Workers in Destination Countries

In the fourth article in a six-part PLoS Medicine series on Migration & Health, Joan Benach and colleagues discuss the specific health risks and policy needs associated with migration in destination countries, especially for low-skilled and illegal migrant workers

Substrate promiscuity of inositol 1,4,5-trisphosphate kinase driven by structurally-modified ligands and active site plasticity

D-myo-inositol 1,4,5-trisphosphate (InsP3) is a fundamental second messenger in cellular Ca2+ mobilization. InsP3 3-kinase, a highly specific enzyme binding InsP3 in just one mode, phosphorylates InsP3 specifically at its secondary 3-hydroxyl group to generate a tetrakisphosphate. Using a chemical biology approach with both synthetised and established ligands, combining synthesis, crystallography, computational docking, HPLC and fluorescence polarization binding assays using fluorescently-tagged InsP3, we have surveyed the limits of InsP3 3-kinase ligand specificity and uncovered surprisingly unforeseen biosynthetic capacity. Structurally-modified ligands exploit active site plasticity generating a helix-tilt. These facilitated uncovering of unexpected substrates phosphorylated at a surrogate extended primary hydroxyl at the inositol pseudo 3-position, applicable even to carbohydrate-based substrates. Crystallization experiments designed to allow reactions to proceed in situ facilitated unequivocal characterization of the atypical tetrakisphosphate products. In summary, we define features of InsP3 3-kinase plasticity and substrate tolerance that may be more widely exploitable

δ-Aminolevulinic acid cytotoxic effects on human hepatocarcinoma cell lines

BACKGROUND: Acute Intermittent Porphyria is a genetic disorder of heme metabolism, characterized by increased levels of porphyrin precursors, δ-aminolevulinic acid (ALA) and porphobilinogen (PBG). ALA has been reported to generate reactive oxygen species and to cause oxidative damage to proteins, subcellular structures and DNA. It is known that oxidative stress can induce apoptosis. The aim of this work was to study the cytotoxic effect of ALA on two hepatocarcinoma cell lines. RESULTS: We have determined the impact of ALA on HEP G2 and HEP 3B hepatocarcinoma cell lines survival as measured by the MTT assay. ALA proved to be cytotoxic in both cell lines however; HEP G2 was more sensitive to ALA than HEP 3B. Addition of hemin or glucose diminished ALA cytotoxicity in HEP G2 cells; instead it was enhanced in HEP 3B cells. Because apoptosis is usually associated with DNA fragmentation, the DNA of ALA treated and untreated cells were analyzed. The characteristic pattern of DNA fragmentation ladders was observed in ALA treated cells. To elucidate the mechanisms of ALA induced apoptosis, we examined its effect on p53 expression. No changes in p53 mRNA levels were observed after exposure of both cell lines to ALA for 24 h. CDK2 and CDK4 protein levels were reduced after ALA treatment at physiological concentrations

Latin Americans show wide-spread Converso ancestry and imprint of local Native ancestry on physical appearance

Historical records and genetic analyses indicate that Latin Americans trace their ancestry mainly to the intermixing (admixture) of Native Americans, Europeans and Sub-Saharan Africans. Using novel haplotype-based methods, here we infer sub-continental ancestry in over 6,500 Latin Americans and evaluate the impact of regional ancestry variation on physical appearance. We find that Native American ancestry components in Latin Americans correspond geographically to the present-day genetic structure of Native groups, and that sources of non-Native ancestry, and admixture timings, match documented migratory flows. We also detect South/East Mediterranean ancestry across Latin America, probably stemming mostly from the clandestine colonial migration of Christian converts of non-European origin (Conversos). Furthermore, we find that ancestry related to highland (Central Andean) versus lowland (Mapuche) Natives is associated with variation in facial features, particularly nose morphology, and detect significant differences in allele frequencies between these groups at loci previously associated with nose morphology in this sample.Instituto Multidisciplinario de Biología Celula

Latin Americans show wide-spread Converso ancestry and imprint of local Native ancestry on physical appearance

Historical records and genetic analyses indicate that Latin Americans trace their ancestry mainly to the intermixing (admixture) of Native Americans, Europeans and Sub-Saharan Africans. Using novel haplotype-based methods, here we infer sub-continental ancestry in over 6,500 Latin Americans and evaluate the impact of regional ancestry variation on physical appearance. We find that Native American ancestry components in Latin Americans correspond geographically to the present-day genetic structure of Native groups, and that sources of non-Native ancestry, and admixture timings, match documented migratory flows. We also detect South/East Mediterranean ancestry across Latin America, probably stemming mostly from the clandestine colonial migration of Christian converts of non-European origin (Conversos). Furthermore, we find that ancestry related to highland (Central Andean) versus lowland (Mapuche) Natives is associated with variation in facial features, particularly nose morphology, and detect significant differences in allele frequencies between these groups at loci previously associated with nose morphology in this sample.Instituto Multidisciplinario de Biología Celula