El ciclo porcino y sus indicadores : período 1980 - 1991

p.49-57El análisis económico de la producción porcina de la Argentina en el período comprendido entre los año 1980 y 1991 demuestra 3 variaciones cíclicas, así como la estacionalidad de la producción con un máximo de cabezas comercializadas en agosto hasta noviembre y un descenso a partir de diciembre hasta julio. El número de cabezas de ganado porcino comercializado disminuyó considerablemente a lo largo de estos 12 años, así como también el volumen registrado en el M ercado de Liniers del 61 por ciento al 20 por ciento. Los precios en cambio sufrieron un leve aumento. Se estudiaron como indicadores del ciclo porcino la relación porcino-maíz, porcino-sorgo, porcino-vacuno, porcino-pollo y porcino-reproductores vendidos en Palermo. De el análisis estadístico de los indicadores sólo se observa altas correlaciones entre el precio de los reproductores en Palermo-precio de los capones del mismo año en Liniers

Data-driven Models to Anticipate Critical Voltage Events in Power Systems

This paper explores the effectiveness of data-driven models to predict voltage excursion events in power systems using simple categorical labels. By treating the prediction as a categorical classification task, the workflow is characterized by a low computational and data burden. A proof-of-concept case study on a real portion of the Italian 150 kV sub-transmission network, which hosts a significant amount of wind power generation, demonstrates the general validity of the proposal and offers insight into the strengths and weaknesses of several widely utilized prediction models for this application.Comment: In proceedings of the 11th Bulk Power Systems Dynamics and Control Symposium (IREP 2022), July 25-30, 2022, Banff, Canad

Accretion and photodesorption of CO ice as a function of the incident angle of deposition

Non-thermal desorption of inter- and circum-stellar ice mantles on dust grains, in particular ultraviolet photon-induced desorption, has gained importance in recent years. These processes may account for the observed gas phase abundances of molecules like CO toward cold interstellar clouds. Ice mantle growth results from gas molecules impinging on the dust from all directions and incidence angles. Nevertheless, the effect of the incident angle for deposition on ice photo-desorption rate has not been studied. This work explores the impact on the accretion and photodesorption rates of the incidence angle of CO gas molecules with the cold surface during deposition of a CO ice layer. Infrared spectroscopy monitored CO ice upon deposition at different angles, ultraviolet-irradiation, and subsequent warm-up. Vacuum-ultraviolet spectroscopy and a Ni-mesh measured the emission of the ultraviolet lamp. Molecules ejected from the ice to the gas during irradiation or warm-up were characterized by a quadrupole mass spectrometer. The photodesorption rate of CO ice deposited at 11 K and different incident angles was rather stable between 0 and 45$^{\circ}$. A maximum in the CO photodesorption rate appeared around 70$^{\circ}$-incidence deposition angle. The same deposition angle leads to the maximum surface area of water ice. Although this study of the surface area could not be performed for CO ice, the similar angle dependence in the photodesorption and the ice surface area suggests that they are closely related. Further evidence for a dependence of CO ice morphology on deposition angle is provided by thermal desorption of CO ice experiments

Nature-Inspired Interconnects for Self-Assembled Large-Scale Network-on-Chip Designs

Future nano-scale electronics built up from an Avogadro number of components needs efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the Networks-on-Chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design trade-offs and properties of an irregular, abstract, yet physically plausible 3D small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, the number of switch nodes, the distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nano-scale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local 2D and 3D regular topologies

eHealth literacy scale: a nursing analysis and Italian validation

Background: One of the scales most used to measure quickly and easily eHealth Literacy is the eHealth LiteracyScale (eHEALS); however, there was no validation of this scale in Italian. Therefore, the aim of this study was to adapt and validate the eHealth Literacy Scale (eHEALS) to the italian context. Methods: Italian translation of eHEALS was administered along unit to another two scale for measure lifestyle habits self-esteem and life satisfaction). A sample of 650 university students aged between 18 and 45 years was selected. An exploratory factor analysis, confirmatory factor analysis, analysis of invariance, reliability, stability and bivariate correlations were performed. Results: Exploratory factor analysis revealed a monofactorial structure that explained 67% of variance. Reliability of 0.87 and test-retest correlation of 0.78 was obtained. The questionnaire was invariant by gender. Regarding the criterion validity, a statistically significant and positive correlations between 0.05 and 0.15 with three indicators was obtained (self-esteem, lifestyle habits and life satisfaction). The italian version of the eHEALS tested in this work has shown to be a valid and reliable scale to measure eHealth competence in university students

Phasing diffuse scattering. Application of the SIR2002 algorithm to the non-crystallographic phase problem

A new phasing algorithm has been used to determine the phases of diffuse elastic X-ray scattering from a non-periodic array of gold balls of 50 nm diameter. Two-dimensional real-space images, showing the charge-density distribution of the balls, have been reconstructed at 50 nm resolution from transmission diffraction patterns recorded at 550 eV energy. The reconstructed image fits well with scanning electron microscope (SEM) image of the same sample. The algorithm, which uses only the density modification portion of the SIR2002 program, is compared with the results obtained via the Gerchberg-Saxton-Fienup HIO algorithm. In this way the relationship between density modification in crystallography and the HiO algorithm used in signal and image processing is elucidated.Comment: 7 pages, 12 figure

Theory of Room Temperature Ferromagnet V(TCNE)_x (1.5 < x < 2): Role of Hidden Flat Bands

Theoretical studies on the possible origin of room temperature ferromagnetism (ferromagnetic once crystallized) in the molecular transition metal complex, V(TCNE)_x (1.5<x<2) have been carried out. For this family, there have been no definite understanding of crystal structure so far because of sample quality, though the effective valence of V is known to be close to +2. Proposing a new crystal structure for the stoichiometric case of x=2, where the valence of each TCNE molecule is -1 and resistivity shows insulating behavior, exchange interaction among d-electrons on adjacent V atoms has been estimated based on the cluster with 3 vanadium atoms and one TCNE molecule. It turns out that Hund's coupling among d orbitals within the same V atoms and antiferromagnetic coupling between d oribitals and LUMO of TCNE (bridging V atoms) due to hybridization result in overall ferromagnetism (to be precise, ferrimagnetism). This view based on localized electrons is supplemented by the band picture, which indicates the existence of a flat band expected to lead to ferromagnetism as well consistent with the localized view. The off-stoichiometric cases (x<2), which still show ferromagnetism but semiconducting transport properties, have been analyzed as due to Anderson localization.Comment: Accepted for publication in J. Phys. Soc. Jpn. Vol.79 (2010), No. 3 (March issue), in press; 6 pages, 8 figure

Las políticas públicas de ciencia y tecnología agropecuarias y su efecto sobre el desarrollo de la producción de pequeños rumiantes en Argentina

En el sector de los pequeños rumiantes (PPR) en Argentina prevalecen pequeños y medianos productores, con escaso dinamismo tecnológico y empresarial, para los cuales los procesos de aprendizaje se desarrollan con una participación central de Instituciones de Ciencia y Tecnología como fuentes de generación de conocimientos aplicados a través de la asistencia integral que pueden ser determinantes para la adopción de tecnologías adecuadas. Se analizaron los efectos de las políticas públicas sobre CTI orientadas a promover el desarrollo de los PPR, conformando un mapa de relaciones. La investigación de tipo cualitativa consideró ovinos y caprinos, describiendo el contexto y permitiendo dar cuenta de su particularidad y complejidad, yendo de lo particular a lo general. Se relevó la información publicada, se contactaron actores relacionados con el sector y se determinaron distintos niveles y modalidades de participación de las ICyT y la existencia de espacios de interacción entre los diferentes grupos de actores que intervienen en el sector. Se encontraron diversos tipos de políticas públicas en ciencia y tecnología que ofrecen oportunidades al sector y se determinaron distintos niveles y modalidades de participación de las ICyT y la existencia de espacios de interacción o vínculos entre los diferentes grupos de actores que intervienen. A fin de identificar el rol funcional de cada actor y cómo se vinculan a nivel nacional, se aplicó el modelo funcional de sistemas de innovación, identificándose cuatro tipos de actores que intervienen en la trama. Se recomiendan dos aspectos centrales para ser considerados en el diseño de estrategias y acciones en materia de CTI orientadas a la producción de pequeños rumiantes, trabajar con una perspectiva sistémica del mismo y fortalecer los vínculos conformando redes interinstitucionales que permitan profundizar los avances en el conocimiento, dar respuestas tecnológicas orientadas a necesidades concretas