Comportamiento del estaño durante la fusión y la solidificación

Se estudia el comportamiento del Sn analíticamente puro durante la solidificación controlada de pequeñas muestras, utilizando métodos calorimétricos y curvas de enfriamiento asistidas por cálculo. Dado que la solidificación se produce siempre después de un sobre-enfriamiento inicial, se analiza la dependencia de este sobre-enfriamiento máximo alcanzado en función de la velocidad de enfriamiento de la muestra. Se comprobó también que el valor del sobre-enfriamiento depende de la temperatura máxima alcanzada por el líquido antes del enfriamiento, hallándose un cambio en el comportamiento cuando el líquido se eleva por encima de los 723K aproximadamente. Si bien este comportamiento continúa en estudio, se lo atribuye a algún cambio en las propiedades del Sn en estado líquido.The behavior of small samples of analytically pure Sn during controlled solidification was studied by use of scanning calorimetry and cooling curves analysis. Since the solidification always occurs after an initial under-cooling, the dependence of the maximum value reached is analyzed against the cooling rate of the sample. It was also found that the value of the under-cooling depends on the maximum temperature reached by the liquid prior to cooling,a behavior change was found when the liquid is over-heated above 723K approximately. This behavior is still under study, but we assume that some kind of liquid-state change could be present

Mid-Season High-Resolution Satellite Imagery for Forecasting Site-Specific Corn Yield

Citation: Peralta, N.R.; Assefa, Y.; Du, J.; Barden, C.J.; Ciampitti, I.A. Mid-Season High-Resolution Satellite Imagery for Forecasting Site-Specific Corn Yield. Remote Sens. 2016, 8, 848.This technical note presents the first Sentinel-2 data service platform for obtaining atmospherically-corrected images and generating the corresponding value-added products for any land surface on Earth (http://s2.boku.eodc.eu/). Using the European Space Agency’s (ESA) Sen2Cor algorithm, the platform processes ESA’s Level-1C top-of-atmosphere reflectance to atmospherically-corrected bottom-of-atmosphere (BoA) reflectance (Level-2A). The processing runs on-demand, with a global coverage, on the Earth Observation Data Centre (EODC), which is a public-private collaborative IT infrastructure in Vienna (Austria) for archiving, processing, and distributing Earth observation (EO) data (http://www.eodc.eu). Using the data service platform, users can submit processing requests and access the results via a user-friendly web page or using a dedicated application programming interface (API). Building on the processed Level-2A data, the platform also creates value-added products with a particular focus on agricultural vegetation monitoring, such as leaf area index (LAI) and broadband hemispherical-directional reflectance factor (HDRF). An analysis of the performance of the data service platform, along with processing capacity, is presented. Some preliminary consistency checks of the algorithm implementation are included to demonstrate the expected product quality. In particular, Sentinel-2 data were compared to atmospherically-corrected Landsat-8 data for six test sites achieving a R2 = 0.90 and Root Mean Square Error (RMSE) = 0.031. LAI was validated for one test site using ground estimations. Results show a very good agreement (R2 = 0.83) and a RMSE of 0.32 m2/m2 (12% of mean value)

Modeling the Mg I from the NUV to MIR. I. The solar case

Context. Semi-empirical models of the solar atmosphere are used to study the radiative environment of any planet in our Solar System. There is a need for reliable atomic data for neutral atoms and ions in the atmosphere to obtain improved calculated spectra. Atomic parameters are crucial to computing the correct population of elements through the whole stellar atmosphere. Although there is very good agreement between the observed and calculated spectra for the Sun, there is still a mismatch in several spectral ranges due to the lack of atomic data and the inaccuracies thereof, particularly for neutrals such as Mga» I. Aims. To represent many spectral lines of Mga» I from the near-ultraviolet to the mid-infrared correctly, it is necessary to add and update the atomic data involved in the atomic processes that drive their formation. Methods. The improvements made to the Mga» I atomic model are as follows: i) 127 strong lines, including their broadening data, were added. ii) To obtain these new lines, we increased the number of energy levels from 26 to 85. iii) Photoionization cross-section parameters were added and updated. iv) Effective collision strength (I' ij ) parameters were updated for the first 25 levels using the existing data from the convergent close-coupling calculations. One of the most significant changes in our model is given by the new I' ij parameters for transitions involving levels between 26 and 54, which were computed with a multiconfiguration Breit-Pauli distorted-wave (DW) method. For transitions involving superlevels, we calculated the I' ij parameters with the usual semi-empirical formulas. Results. More than 100 transitions were added to our calculations, increasing our capability of reproducing important features observed in the solar spectra. We found a remarkable improvement in matching the solar spectra for wavelengths higher than 30 000 Å when our new DW I' ij data were used in the model.Fil: Peralta, Juan Ignacio. Universidad Nacional de Tres de Febrero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Vieytes, Mariela Cristina. Universidad Nacional de Tres de Febrero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Mid-Season High-Resolution Satellite Imagery for Forecasting Site-Specific Corn Yield

A timely and accurate crop yield forecast is crucial to make better decisions on crop management, marketing, and storage by assessing ahead and implementing based on expected crop performance. The objective of this study was to investigate the potential of high-resolution satellite imagery data collected at midgrowing season for identification of within-field variability and to forecast corn yield at different sites within a field. A test was conducted on yield monitor data and RapidEye satellite imagery obtained for 22 cornfields located in five different counties (Clay, Dickinson, Rice, Saline, and Washington) of Kansas (total of 457 ha). Three basic tests were conducted on the data: (1) spatial dependence on each of the yield and vegetation indices (VIs) using Moran’s I test; (2) model selection for the relationship between imagery data and actual yield using ordinary least square regression (OLS) and spatial econometric (SPL) models; and (3) model validation for yield forecasting purposes. Spatial autocorrelation analysis (Moran’s I test) for both yield and VIs (red edge NDVI = NDVIre, normalized difference vegetation index = NDVIr, SRre = red-edge simple ratio, near infrared = NIR and green-NDVI = NDVIG) was tested positive and statistically significant for most of the fields (p < 0.05), except for one. Inclusion of spatial adjustment to model improved the model fit on most fields as compared to OLS models, with the spatial adjustment coefficient significant for half of the fields studied. When selected models were used for prediction to validate dataset, a striking similarity (RMSE = 0.02) was obtained between predicted and observed yield within a field. Yield maps could assist implementing more effective site-specific management tools and could be utilized as a proxy of yield monitor data. In summary, high-resolution satellite imagery data can be reasonably used to forecast yield via utilization of models that include spatial adjustment to inform precision agricultural management decisions.Sociedad Argentina de Informática e Investigación Operativ

Mental and Physical Health and Hygienic, Nutritional and Daily Habits during Quarantine in COVID-19 Pandemic

Introduction: The outbreak of the new coronavirus (COVID-19) was declaredas a pandemic by the World Health Organization in March 2020. TheArgentinian government adopted a preventive social isolation and lockdownstrategy as an exceptional measure in this critical world context. This lockdownstrategy has kept a large number of people in isolation and affectedmany aspects of people?s lives. Objective: To describe the physical and mentalhealth status and possible changes in hygienic, nutritional and, daily habitsduring quarantine in the COVID-19 pandemic. Materials and Method: Anonline anonymous survey was sent to the general population of Buenos Airescity, 434 people answered the questionnaire. Results: Fifty-one percent ofrespondents were between 40 and 70 years old. Most respondents were female(75.8%) and had higher education (62.2%). Thirty point eight percent had apre-existing disease and in 50.7% of these cases, the usual symptoms experiencedby respondents remained unchanged. The onsets of anxiety (38.2%),depression symptoms (27.9%), sleep disorders (20.5%), and irritability(27.2%) were reported during the isolation period. Also, changes in eatinghabits (55.5%) were reported. Significant improvement was reported in personalhygiene (80.2%) and home cleaning (81.3%) habits. It was also observedthat despite the isolation some people continued doing physical activity.Conclusions: Respondents did not report significant changes in the symptomsof their preexisting diseases and had a positive mindset towards personalhygiene and home cleaning. Also, reported continuity in physical activity during isolation. However, the onset of psychiatric symptoms such as anxiety, depression, irritability and sleep problems, and, changes in eating habits were observed during the quarantine.Fil: Dillon, Carol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Universidad de Palermo; ArgentinaFil: Pérez Leguizamón, Patricio Rosendo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Castro, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Guelar, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Garcia, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Feldman, Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Leis, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Romano, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Peralta, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Rojas, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Maggi, Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Viaggio, María Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentin

Aproximación a estrategias de diseño para la re densificación de tejidos existentes.

Ponencia presentada en el 1º Encuentro de Investigadores que estudian la ciudad de Córdoba. Mar del Plata, Buenos Aires. 2014La ciudad entendida como la construcción cultural del hombre por excelencia, es el lugar donde ocurren las cosas. La ciudad como soporte físico espacial de la simultaneidad de la vida y las personas. La ciudad como fruto del trabajo colectivo de una sociedad. En tanto acumulación histórica se expresa como superposición de estratos y fenómenos constituyéndose en el soporte material donde se ponen de manifiesto los conflictos sociales y la disputa de intereses diversos. La ciudad crece y esa es su característica desde que es ya nuestra segunda naturaleza. Crece la población, crecen las necesidades, crecen las respuestas. El territorio se transforma conforme las lógicas urbanas predominantes en cada época, casi siempre por detrás de las modificaciones que tiene lugar en las estructuras sociales, aunque de manera persistente estableciendo cambios y permanencias. El debate es acerca de como crece, cuanto, donde, con quien. No obstante, entre el impacto de los cambios denominados ?globales? juntamente a la persistencia de la ciudad moderna ?aumento de las asimetrías en el acceso al suelo, a la vivienda, equipamiento e infraestructura; estrategias de integración regional y procesos de descentralización - desconcentración que vienen modificando la continuidad espacial y afectando a los centros tradicionales y al espacio urbano en su conjunto?, la creciente necesidad de direccionar los procesos de crecimiento cada vez más multi - direccionales y complejos, el concepto de ?renovación urbana? ha adquirido desde la teoría y la práctica urbana nuevos significados, que aún, en sus distintas acepciones encuentra a la ciudad construida como protagonista del desarrollo. En este contexto, es de suma importancia el estudio de los procesos involucrados en el concepto de renovación urbana, las formas de intervención en la ciudad construida. Se trata, por un lado, de contrarrestar el crecimiento extensivo y fragmentado con políticas y acciones que tiendan a un crecimiento intensivo, tal comos señala J. Borja (1998:53) ??la ciudad del mañana se construye reinventando la ciudad del pasado y diseñando ciudad en las fronteras de la ciudad actual??. Intentar estas transformaciones dirigidas a partir de fuertes apuestas en nuevos programas, nuevas actividades, articulados con nuevos esquemas de movilidad valorizando y reposicionando amplios sectores de la ciudad construida. La ciudad compacta es un sistema de mayor complejidad que puede reducir el consumo de recursos mediante la intensificación de los usos y la generación continua de relaciones entre sus componentes. Articulada con una diversidad de tejidos urbanos que favorezcan la legibilidad de la ciudad por parte de sus habitantes es posible trabajar para la existencia de una identidad colectiva caracterizada por su legibilidad, sentido de pertenencia, accesibilidad, soporte de cooperación, diversidad y capacidad de contener una trama de continuidad con el resto de los tejidos.Fil: Faraci, Mariano. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Litvin, Federico. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Barrionuevo, Juan Ignacio. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Kustich, Iván. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Peralta, Diego. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Madrid, Daniel. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Massanet, Agustín. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Piccardo, Mariano. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Zuzaya, Elizabeth. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaEstudios Urbanos (Planeamiento y Desarrollo

Clogging transition of many-particle systems flowing through bottlenecks

When a large set of discrete bodies passes through a bottleneck, the flow may become intermittent due to the development of clogs that obstruct the constriction. Clogging is observed, for instance, in colloidal suspensions, granular materials and crowd swarming, where consequences may be dramatic. Despite its ubiquity, a general framework embracing research in such a wide variety of scenarios is still lacking. We show that in systems of very different nature and scale -including sheep herds, pedestrian crowds, assemblies of grains, and colloids- the probability distribution of time lapses between the passages of consecutive bodies exhibits a power-law tail with an exponent that depends on the system condition. Consequently, we identify the transition to clogging in terms of the divergence of the average time lapse. Such a unified description allows us to put forward a qualitative clogging state diagram whose most conspicuous feature is the presence of a length scale qualitatively related to the presence of a finite size orifice. This approach helps to understand paradoxical phenomena, such as the faster-is-slower effect predicted for pedestrians evacuating a room and might become a starting point for researchers working in a wide variety of situations where clogging represents a hindrance.Fil: Zuriguel, Iker. Universidad de Navarra; EspañaFil: Parisi, Daniel Ricardo. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hidalgo, Raúl Cruz. Universidad de Navarra; EspañaFil: Lozano, Celia. Universidad de Navarra; EspañaFil: Janda, Álvaro. University of Edinburgh; Reino UnidoFil: Gago, Paula Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional La Plata. Departamento de Ingeniería Mecánica; ArgentinaFil: Peralta, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional La Plata. Departamento de Ingeniería Mecánica; ArgentinaFil: Ferrer, Luis Miguel. Universidad de Zaragoza; EspañaFil: Pugnaloni, Luis Ariel. Universidad Tecnológica Nacional. Facultad Regional La Plata. Departamento de Ingeniería Mecánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Clément, Eric. Universite Pierre et Marie Curie; Francia. Université Paris Diderot - Paris 7; FranciaFil: Maza, Diego. Universidad de Navarra; EspañaFil: Pagonabarraga, Ignacio. Universidad de Barcelona; EspañaFil: Garcimartín, Angel. Universidad de Navarra; Españ

Magnesium Inhibits Wnt/β-Catenin Activity and Reverses the Osteogenic Transformation of Vascular Smooth Muscle Cells

Magnesium reduces vascular smooth muscle cell (VSMC) calcification in vitro but the mechanism has not been revealed so far. This work used only slightly increased magnesium levels and aimed at determining: a) whether inhibition of magnesium transport into the cell influences VSMC calcification, b) whether Wnt/β-catenin signaling, a key mediator of osteogenic differentiation, is modified by magnesium and c) whether magnesium can influence already established vascular calcification. Human VSMC incubated with high phosphate (3.3 mM) and moderately elevated magnesium (1.4 mM) significantly reduced VSMC calcification and expression of the osteogenic transcription factors Cbfa-1 and osterix, and up-regulated expression of the natural calcification inhibitors matrix Gla protein (MGP) and osteoprotegerin (OPG). The protective effects of magnesium on calcification and expression of osteogenic markers were no longer observed in VSMC cultured with an inhibitor of cellular magnesium transport (2-aminoethoxy-diphenylborate [2-APB]). High phosphate induced activation of Wnt/β-catenin pathway as demonstrated by the translocation of β-catenin into the nucleus, increased expression of the frizzled-3 gene, and downregulation of Dkk-1 gene, a specific antagonist of the Wnt/β-catenin signaling pathway. The addition of magnesium however inhibited phosphate-induced activation of Wnt/β-catenin signaling pathway. Furthermore, TRPM7 silencing using siRNA resulted in activation of Wnt/β-catenin signaling pathway. Additional experiments were performed to test the ability of magnesium to halt the progression of already established VSMC calcification in vitro. The delayed addition of magnesium decreased calcium content, down-regulated Cbfa-1 and osterix and up-regulated MGP and OPG, when compared with a control group. This effect was not observed when 2-APB was added. In conclusion, magnesium transport through the cell membrane is important to inhibit VSMC calcification in vitro. Inhibition of Wnt/β-catenin by magnesium is one potential intracellular mechanism by which this anti-calcifying effect is achieved