Looking for what it means to learn to program and how it is taught at schools

Este escrito recupera la demanda estudiantil de encontrarle sentido a aquello que están aprendiendo en escuelas técnicas de Córdoba capital que enseñan programación. A través de una análisis de caso se realizó una investigación cualitativa en la que se construyeron categorías a medida que se analizaron entrevistas, observaciones y grupos focales en escuelas técnicas con orientación en programación. Como emergente de ello, se identificó que el grupo estudiantil vinculaba al trabajo en computación como algo poco visible que se relacionaba directamente a no encontrarle sentido ni utilidad a eso que estaban aprendiendo. Esto nos permite abordar algunas reflexiones sobre la importancia, no sólo de aquello que vayamos a enseñar (contenido) sino también de cómo lo haremos (su forma), lo cual nos posibilita seguir aportando al desarrollo de una didáctica de las Ciencias de la Computación.This paper recovers the student's demand to make sense of learning programming in technical schools in Córdoba city. Through a case analysis, a qualitative research was carried out in which categories were built as interviews, observations and focus groups in technical schools oriented to programming were analyzed. As a result, it was identified that the student group linked the work in computing as something not very visible that was directly related to not finding meaning or usefulness in what they were learning. This allows us to address some reflections on the importance, not only of what we are going to teach (content) but also how we are going to teach it (its form), which allows us to continue contributing to the development of the didactics of Computer Science.Sociedad Argentina de Informática e Investigación Operativ

Size-dependence of volatile and semi-volatile organic carbon content in phytoplankton cells

The content of volatile and semivolatile organic compounds (VOC and SOC), measured as exchangeable dissolved organic carbon (EDOC), was quantified in 9 phytoplanktonic species that spanned 4 orders of magnitude in cell volume, by disrupting the cells and quantifying the gaseous organic carbon released. EDOC content varied 4 orders of magnitude, from 0.0015 to 14.12 pg C cell−1 in the species studied and increased linearly with increasing phytoplankton cell volume following the equation EDOC (pg C cell−1) = −2.35 × cellular volume (CV, μm3 cell−1) 0.90 (± 0.3), with a slope (0.90) not different from 1 indicating a constant increase in volatile carbon as the cell size of phytoplankton increased. The percentage of EDOC relative to total cellular carbon was small but varied 20 fold from 0.28 to 5.17%, and no obvious taxonomic pattern in the content of EDOC was appreciable for the species tested. The cell release rate of EDOC is small compared to the amount of carbon in the cell and difficult to capture. Nonetheless, the results point to a potentialf flux of volatile and semivolatile phytoplankton-derived organic carbon to the atmosphere that has been largely underestimated and deserves further attention in the future.This is a contribution to the “Malaspina 2010” COSOLIDER project funded by the Spanish Ministry of Science and Innovation (CSD2008-00077).Peer reviewedPeer Reviewe

The subjective metric of remembered colors: A Fisher-information analysis of the geometry of human chromatic memory.

In order to explore the metric structure of the space of remembered colors, a computer game was designed, where players with normal color vision had to store a color in memory, and later retrieve it by selecting the best match out of a continuum of alternatives. All tested subjects exhibited evidence of focal colors in their mnemonic strategy. We found no concluding evidence that the focal colors of different players tended to cluster around universal prototypes. Based on the Fisher metric, for each subject we defined a notion of distance in color space that captured the accuracy with which similar colors where discriminated or confounded when stored and retrieved from memory. The notions of distance obtained for different players were remarkably similar. Finally, for each player, we constructed a new color scale, in which colors are memorized and retrieved with uniform accuracy

UrdA Controls Secondary Metabolite Production and the Balance between Asexual and Sexual Development in Aspergillus Nidulans

The genus Aspergillus includes important plant pathogens, opportunistic human pathogens and mycotoxigenic fungi. In these organisms, secondary metabolism and morphogenesis are subject to a complex genetic regulation. Here we functionally characterized urdA, a gene encoding a putative helix-loop-helix (HLH)-type regulator in the model fungus Aspergillus nidulans. urdA governs asexual and sexual development in strains with a wild-type veA background; absence of urdA resulted in severe morphological alterations, with a significant reduction of conidial production and an increase in cleistothecial formation, even in the presence of light, a repressor of sex. The positive effect of urdA on conidiation is mediated by the central developmental pathway (CDP). However, brlA overexpression was not sufficient to restore wild-type conidiation in the Delta urdA strain. Heterologous complementation of Delta urdA with the putative Aspergillus flavus urdA homolog also failed to rescue conidiation wild-type levels, indicating that both genes perform different functions, probably reflected by key sequence divergence. UrdA also represses sterigmatocystin (ST) toxin production in the presence of light by affecting the expression of aflR, the activator of the ST gene cluster. Furthermore, UrdA regulates the production of several unknown secondary metabolites, revealing a broader regulatory scope. Interestingly, UrdA affects the abundance and distribution of the VeA protein in hyphae, and our genetics studies indicated that veA appears epistatic to urdA regarding ST production. However, the distinct fluffy phenotype of the Delta urdA Delta veA double mutant suggests that both regulators conduct independent developmental roles. Overall, these results suggest that UrdA plays a pivotal role in the coordination of development and secondary metabolism in A. nidulans.This research and The APC was supported by the Department of Biological Sciences at Northern Illinois University. The research at CIB-CSIC was funded by MINECO/FEDER/EU (grant BFU2015-66806-R). The research at UPV/EHU was funded by grant EHUA15/08

Regeneración de la superficie ocular: stem cells/células madre y técnicas reconstructivas Regeneration of the ocular

La córnea es un tejido transparente constituido microscópicamente por 5 capas bien diferenciadas. El epitelio corneal es esencial para la transparencia corneal y se encuentra en continua renovación a lo largo de la vida a partir de la población de células madre limbocorneales. La localización de estas células madre limbocorneales parece residir en las capas basales del epitelio limbocorneal, de vital importancia para mantener el microambiente de estas células madre limbocorneales, que depende de una variedad de factores intrínsecos y extrínsecos. La insuficiencia límbica se produce cuando ocurre una pérdida parcial o total de estas células madre limbocorneales. Este cuadro lleva a una opacificación corneal con la consiguiente pérdida de visión. En estos casos, el trasplante corneal supone únicamente un reemplazo temporal del epitelio corneal; es necesario llevar a cabo un tratamiento previo con trasplante de limbo autólogo o alogénico, que permita regenerar la población de células limbocorneales dañadas. Para disminuir el riesgo que supone el trasplante de limbo en el ojo donante, se han propuesto técnicas de cultivo de células limbocorneales a partir de pequeñas biopsias limbocorneales

Evaluación de la respuesta serológica contra IBR a partir de la utilización de vacunas polivalentes disponibles en el mercado.

La Rinotraqueítis infecciosa bovina (IBR) es una enfermedad de distribución mundial que provoca grandes pérdidas económicas en nuestro país y el mundo. En la provincia de La Pampa se ha reportado su presencia y amplia distribución territorial. En general la prevención de IBR ha estado centrada en la utilización de vacunas polivalentes. El objetivo del presente trabajo fue evaluar la respuesta serológica a través de los niveles de anticuerpos presentes. Para ello se utilizaron 3 vacunas comerciales polivalentes que contenían en su formulación Herpesvirus bovino tipo 1 (BVH1) inactivado. Se utilizaron 4 grupos de terneros. G1 estuvo integrado por 14 animales, G2 y G3 por 13 animales y G4 o control (-) por 9 animales. Los animales fueron vacunados en dos oportunidades con un intervalo de 21 días. Para la detección de anticuerpos se utilizó un kit de ELISA. Al finalizar el ensayo al día 42 el porcentaje de animales que presentaron anticuerpos vacunales contra IBR fue del 42,8%, 61,5% y 38,4% para los grupos G1, G2 y G3 respectivamente y de 0% para los animales de G4 o grupo control (-). Las medias geométricas del IRPC (Índice Relativo x 100) en la misma fecha fueron de 16,31; 27,7 y 15,12 para los grupos G1, G2 y G3 respectivamente. Las vacunas utilizadas desarrollaron anticuerpos contra IBR en todos los grupos inoculados existiendo diferencias en el porcentaje de animales positivos de cada grupo. Los niveles de anticuerpos generados por las diferentes vacunas no presentaron diferencias significativas entre sí. Por último, se encontraron diferencias significativas entre el nivel de anticuerpos generado por las vacunas y los niveles obtenidos por pasaje viral

Mechanical barriers and transforming growth factor beta inhibitor on epidural fibrosis in a rabbit laminectomy model

Background: TGF-β has been described as a mediator of fibrosis and scarring. Several studies achieved reduction in experimental scarring through the inhibition of TGF-β. Fibroblasts have been defined as the cell population originating fibrosis, blocking fibroblast invasion may impair epidural fibrosis appearance. For this purpose, biocompatible materials used as mechanical barriers and a TGF-β inhibitor peptide were evaluated in the reduction of epidural fibrosis. Methods: A L6 laminectomy was performed in 40 New Zealand white rabbits. Divided into four groups, each rabbit was assigned to receive either collagen sponge scaffold (CS group), gelatin-based gel (GCP group), P144® (iTGFβ group), or left untreated (control group). Four weeks after surgery, cell density, collagen content, and new bone formation of the scar area were determined by histomorphometry. Two experienced pathologists scored dura mater adhesion, scar density, and inflammatory infiltrate in a blinded manner. Results: In all groups, laminectomy site was filled with fibrous tissue and the dura mater presented adhesions. Only GCP group presented a significant reduction in collagen content and scar density. Conclusion: GCP treatment reduces epidural fibrosis although did not prevent dura mater adhesion completely

Early Proterozoic calc-alkaline and Middle Proterozoic tholeiitic dyke swarms from Central-Eastern Argentina: Petrology, geochemistry, Sr-Nd isotopes and tectonic implications

The Rio de La Plata craton in Argentina (Azul and Tandil regions) is characterized by Early Proterozoic (2·0 Ga) calc-alkaline and Middle Proterozoic (1·6 Ga) tholeiitic dyke swarms intruding the crystalline basement involved in the Transamazonian Orogeny (2·2-1·9 Ga). The calc-alkaline dykes have andesitic and rhyolitic compositions and trend east-west, whereas the tholeiitic dykes mainly trend N30°W and are represented by basalts with low (0·9-1·7 wt %) and high TiO2 (up to 3·7 wt %). The calc-alkaline dykes have primitive mantle (PM)-normalized trace element patterns enriched in Rb, Ba, K, La, Ce and Nd, and significant negative Nb and Ti anomalies. These dykes are characterized by εt(Nd) values of - 3 to - 4, similar to those of the EMI mantle component. Low-TiO2 tholeiitic dykes have low incompatible-element (IE) contents and PM-IE patterns with slightly positive or negative Nb spikes. They have variable εt(Nd) values (-0·5 to 12·1), which mainly reflect derivation from a depleted source mantle. High-TiO2 tholeiitic dykes have more enriched IE-PM patterns and are characterized by εt(Nd) values (-1·4 to -7·5) typical of an enriched source mantle. Chemical and isotopic data and melting modelling indicate that both calc-alkaline and tholeiitic dykes originated by different melting degrees of a heterogeneous source mantle, the variable IE enrichment of which may have occured in Late Archaean to Early Proterozoic times. The emplacement of the calc-alkaline dykes is associated with the transtensional stage of the Transamazonian Orogeny, whereas the tholeiitic dykes reflect extensional tectonics succeeding the Transamazonian event. The calc-alkaline and tholeiitic dykes are similar in emplacement age and characteristics to metamorphosed granites and volcanic rocks outcropping within the Namaqua fold belts of southwestern Africa (Richtersveld and Witberg-Aggeneys-Gamsberg provinces); this may indicate that the Rio de La Plata craton and southwestern Africa were contiguous in Early-Middle Proterozoic times.Facultad de Ciencias Naturales y MuseoLaboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológic

Obtención de biomasa de microalga Chlorella vulgaris en un banco de prueba de fotobiorreactores de columna de burbujeo

Dada la agudización de la situación socioeconómica y medioambiental que se enfrenta en la actualidad, los investigadores buscan nuevas alternativas para sustituir el combustible fósil convencional, siendo una salida, los biocombustibles obtenidos a partir de microalgas. El objetivo de esta investigación fue la obtención de biomasa en un banco de prueba de fotobiorreactores de columna de burbujeo, utilizando una cepa de Chlorella vulgaris en medio Bristol. Se dimensionó el fotobiorreactor y se evaluó la influencia de las variables pH y concentración de nitrógeno, con y sin presencia de oligoelementos, sobre la productividaddel crecimiento de la biomasa de microalgas. Seencontró que en el intervalo estudiado (pH entre 6 y 8 y concentración de NaNO3 entre 0,5 y 1 g/L) estas variables no tienen un efecto significativo en el crecimiento, mientras que la presencia de oligoelementos favorece este