Broad-area electron-beam-assisted etching of silicon in sulfur hexafluoride

Includes bibliographical references (page 1583).Silicon etching rates up to 250 Å/min have been observed in an electron-beam-generated He plus SF6 plasma. The etch rate was found to increase linearly with electron beam current density and to be practically independent of the electron acceleration voltage in the range investigated (170-260 V). Profiles of the resulting features show that etching is anisotropic with a vertical-to-horizontal ratio of 2.5 to 3

Thermal behaviour of natural ester based oil used in distribution transformers

This work compares the thermal behavior of a distribution transformer when using as dielectric liquid a mineral oil or natural esters. These cases have been analyzed using Finite Elements Method (FEM) at the software COMSOL Multiphysics® with a 3D-symmetrical model through the Heat Transfer in Solid module. The results of simulations show a higher values of maximum temperature in mineral oil submerged transformer than in natural ester, for the same operational conditions

Effects of splitter Blade Length on disc pump performance

The disc pump operates using boundary layer principle and viscous drag with a relatively low efficiency. There are methods to increase head and efficiency, one of them is the placing of blades sectors or splitter blades in discs. This method has been applied only in the low viscosity fluids pumping (v < 0.1 stokes). This study describe an experimental research in a hight viscocity fluid (v = 2 stokes) with exit angle (32 = 35° and different splitter blades Lengths (Ls) (75, 50, 25%). The purpose is to determinate the splitter blades length that achieves the most effective combination between the blade effect and boundary layer effect in order to increase the energy transmission efficiency from the impeller to the fluid. As result, it can be established that the use of spliter blades is an alternative to increase the performance of the disc pump. The highest efficiency and head were obtained for the gapsize between two discs (b) of 12 mm using a 50% spliter blades length of the main blade length

La evaluación de la Educación Física y las políticas educativas en Colombia. Avatares entre la mente, el papel y el contexto. El caso de Manizales y Villamaría (Caldas)

El presente articulo pretende consolidar los resultados de dos trabajos de investigación desarrollados por los autores en la ciudad de Manizales y el municipio de Villamaría, Caldas, Colombia, los cuales se realizaron con el fin de obtener, no solamente, una descripción sino también, la interpretación y comprensión de las ideas, prácticas evaluativas, instrumentos utilizados por los docentes en su planeación y la aplicación en las clases de Educación Física y su relación con las políticas actuales de evaluación en Colombia. Ambos trabajos estuvieron enmarcados en un enfoque cualitativo, estructurados mediante un diseño emergente y utilizando la codificación como una forma sistemática de desarrollar y refinar las interpretaciones dadas por los docentes y practicantes del área, con el fin de tratar de comprender las ideas y las estrategias evaluativas utilizadas

Predicting aging-related decline in physical performance with sparse electrophysiological source imaging

Objective: We introduce a methodology for selecting biomarkers from activation and connectivity derived from Electrophysiological Source Imaging (ESI). Specifically, we pursue the selection of stable biomarkers associated with cognitive decline based on source activation and connectivity patterns of resting-state EEG theta rhythm, used as predictors of physical performance decline in aging individuals measured by a Gait Speed (GS) slowing. Methods: Our two-step methodology involves estimating ESI using flexible sparse-smooth-nonnegative models, from which activation ESI (aESI) and connectivity ESI (cESI) features are derived. The Stable Sparse Classifier method then selects potential biomarkers related to GS changes. Results and Conclusions: Our predictive models using aESI outperform traditional methods such as the LORETA family. The models combining aESI and cESI features provide the best prediction of GS changes. Potential biomarkers from activation/connectivity patterns involve orbitofrontal and temporal cortical regions. Significance: The proposed methodology contributes to the understanding of activation and connectivity of GS-related ESI and provides features that are potential biomarkers of GS slowing. Given the known relationship between GS decline and cognitive impairment, this preliminary work opens novel paths to predict the progression of healthy and pathological aging and might allow an ESI-based evaluation of rehabilitation programs

CBT system (Computer Based Training) of the Aircraft a-37b, used in the earth course of the combat air command No. 3 (CAMCOM-3) of the Colombian Air Force (FAC)

This article shows the implementation of an integrated and updated education system in the Combat Air Command No.3 as a school of the A-37B team, to give theoretical and virtual practice instruction optimizing strategic processes, increasing productivity, reducing operational and administrative costs in order to promote the commitment and development of human capital to crewmembers of the A-37B team; At the same time, promote technological development and innovation in the personnel that make up the Unit. In this work, the importance of the use of ICT in the educational field and the great contribution it presents in the Colombian Armed Forces is made known

Indicadores edáficos de calidad en suelos con y sin laboreo en cultivo de batata con distintos antecesores

Fueron delimitadas dos áreas de manejo de suelos en INTA IPAF NEA, con distintas historias de laboreo de suelo e iguales cultivos de cobertura antecesora. Luego fue diseñado un experimento factorial anidado en bloques, que consideró los factores laboreo y antecesor como fuentes de variación. El área “sin laboreo” tuvo con anterioridad cuatro años de cultivo de Mucuna cinza, en forma continua con resiembra. El área “con laboreo” tuvo cultivos de algodón, maní, maíz, con sus respectivas labranzas. Una vez delineado el experimento, el cultivo de batata fue trasplantado en 2011, 2012, 2013 de forma convencional en ambas áreas, sobre doce tratamientos antecesores. En cada uno fueron registradas las variables edáficas, físicas, químicas, biológicas: densidad aparente (DAP), infiltración básica (IB), porosidad total (PT), distribución de macroporos (MP), mesoporos (MSP), microporos (MCP), estabilidad de agregados (EA), pH, conductividad eléctrica (CE), carbono orgánico total (COT), nitrógeno total (NT), fósforo extractable (Pe), calcio (Ca), magnesio (Mg), potasio (K), sodio (Na), capacidad de intercambio catiónico (CIC), respiración (AB), carbono en la biomasa microbiana (CBM), coeficientes metabólicos (qCO2), fluoresceína difosfato (FDA) , fosfatasa ácida (Pasa), glomalinas (PROT) e hifas (H) arbúsculos (A) y vesículas (V) de micorrizas. En suelos sin laboreo hubo interacción significativa con (AB) y (Pasa). La (AB) presentó niveles más altos en suelos sin laboreo, difiriendo a favor en los tratamientos de cobertura precedente de Sorgo o Batata consociada + Canavalia, con relación a Maíz, Mucuna, Canavalia y barbechos. La (Pasa) presentó niveles más altos en los tratamientos Maíz, con relación a tratamientos Canavalia y Batata consociada + Canavalia más bajos. El (K) presento niveles más altos en los tratamientos antecesores Maíz Blanco Duro y Azteca, con relación a Avena y monocultivo de BatataTwo soil management areas differing in tilling history but with the same previous cover crops were established at INTA IPAF NEA. A factorial experiment with two factors, tilling and previous crop, was set up using a nested randomized block design. The “nontilled” area had Mucuna cinza in the four previous years in a continuous crop where reseeding occurred. The tilled area had been cropped with cotton, peanut, and maize. Sweetpotato was transplanted in 2011, 2012, and 2013 on twelve previous crops treatments. The following edaphic, physical, chemical, and biological variables were recorded: apparent density (DAP), basic infiltration (IB), total porosity (PT), distribution of macro pores (DM), medium size pores (MSP) and micro pores (MCP), aggregate stability (EA), pH, electric conductivity (CE), total organic carbon (COT), total nitrogen(NT), extractable phosphorus (Pe), calcium (Ca), magnesium (Mg), potassium (K), sodium (Na),cationic exchangeable capacity (CIC), respiration (AB), microbial biomass carbon (CBM), metabolic coefficients (qCO2), fluorescein diphosphate (FDA) , acid phosphatase (Pasa), glomalins (PROT) and hiphae (H), arbuscules (A), and vesicles (V) of mycorrhizae. In non-tillage soils there was a significant interaction for AB and Pasa. In not tilled soils, AB was higher when the previous cover crop was sorghum or sweetpotato+Canavalia association as compared to maize, Mucuna, Canavalia and fallow; while Pasa was higher in treatments with maize as compared with Canavalia and sweetpotato associated with Canavalia. Potassium showed the highest values when the previous crop was maize Blanco Duro and Azteca as compared to oats or mono cropped sweetpotato.EEA San PedroFil: Ullé, Jorge Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Espindola, José Antonio. EMBRAPA Agrobiologia; BrasilFil: Martínez, Fortunato. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación y Desarrollo Tecnológico para la Agricultura Familiar Region NEA; ArgentinaFil: Martí, Héctor Rubén. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Faggioli, Valeria Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juarez; ArgentinaFil: Ortega y Villasana, Pilar. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Investigación y Desarrollo Tecnológico para la Agricultura Familiar Región NEA; Argentin

Factors associated with cognitive impairment in Latin American older adults: A cross‐sectional observational study of COVID‐19 confinement

INTRODUCTION: The effects of COVID-19 confinement have been severe, especially in older adults. Therefore, we analyzed the factors associated with cognitive impairment (CI) in Latin America (LA). METHODS: We conducted a cross-sectional observational study with a total of 5245 older adults from 10 countries in LA. Measurement: We used the Telephone Montreal Cognitive Assessment (T-MoCA) and the Eight-item Informant Interview to Differentiate Aging and Dementia (AD8) scale. RESULTS: We found that age, depressive symptomatology, bone fractures, being widowed, having a family member with dementia, and unemployment were associated with an increased risk of CI. In contrast, higher education, hypertension with continuous treatment, quarantine, and keeping stimulating cognitive and physical activities were associated with a lower probability of CI. No significant association was found between suffering from diabetes or being retired and CI. DISCUSSION: It is essential to conduct follow-up studies on these factors, considering their relationship with CI and the duration of confinement

Study protocol and rationale of the “Cogniaction project” a cross-sectional and randomized controlled trial about physical activity, brain health, cognition, and educational achievement in schoolchildren

Background: Education and health are crucial topics for public policies as both largely determine the future wellbeing of the society. Currently, several studies recognize that physical activity (PA) benefits brain health in children. However, most of these studies have not been carried out in developing countries or lack the transference into the education field. The Cogni-Action Project is divided into two stages, a cross-sectional study and a crossover-randomized trial. The aim of the first part is to establish the associations of PA, sedentarism, and physical fitness with brain structure and function, cognitive performance and academic achievement in Chilean schoolchildren (10–13 years-old). The aim of the second part is to determinate the acute effects of three PA protocols on neuroelectric indices during a working memory and a reading task. Methods: PA and sedentarism will be self-reported and objectively-assessed with accelerometers in a representative subsample, whilst physical fitness will be evaluated through the ALPHA fitness test battery. Brain structure and function will be assessed by magnetic resonance imaging (MRI) in a randomized subsample. Cognitive performance will be assessed through the NeuroCognitive Performance Test, and academic achievement by school grades. In the second part 32 adolescents (12–13 year-old) will be cross-over randomized to these condition (i) “Moderate-Intensity Continuous Training” (MICT), (ii) “Cooperative High-Intensity Interval Training” (C-HIIT), and (iii) Sedentary condition. Neuroelectric indices will be measures by electroencephalogram (EEG) and eye-tracking, working memory by n-back task and reading comprehension by a reading task

Kelps’ long-distance dispersal: role of ecological/oceanographic processes and implications to marine forest conservation

Long-distance dispersal is one of the main drivers structuring the distribution of marine biodiversity. This study reports the first occurrence of Macrocystis pyrifera and Durvillaea antarctica rafts on the southwestern warm temperate coast of the Atlantic Ocean. Our results indicate that an extreme meteo-oceanographic event, characterized by a northward, displacement of cold sub-Antarctic oceanic waters driven by an extratropical cyclone, could account for these unusual occurrences. A niche model based on known current distribution and maximum entropy principle (MAXENT), revealed the availability of suitable habitats at lower latitudes, outside their actual distribution edges. The distributional boundaries, mainly driven by temperature and irradiance, suggest the existence of environmental suitability in warm temperate areas, as well as in the Northern Hemisphere off Atlantic and Asian coasts. These theoretical edges and respective environmental drivers agree with the physiological affinities of both species, supporting the hypothesis that these variables act as limiting factors for their occurrences in tropical or warmer areas. Emerging regions can function as refuges and stepping-stones, providing substrate with adequate habitat conditions for recruitment of propagules, allowing eventual colonization. Long dispersal events reinforce the need for an extensive discussion on selective management of natural dispersion, biological invasions, refuge mapping and conservation initiatives in a transnational perspective.Agência financiadora / Número do subsídio Portuguese Fundacao para a Ciencia e Tecnologia (FCT) SFRH/BPD/111003/2015 PTDC/MAR-EST/6053/2014 Conselho Nacional de Desenvolvimento Cientifico e Tecnológico CNPq 306917/2009-2 Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior CAPES/PNPD 02828/09-0 CAPES/PNADB 2338000071/2010-61 Polito: CNPQ Universal 447109/2014-6 Instituto Nacional de Ciencia e Tecnologia para Mudancas Climaticas (INCT-MC) ProspecMar-Islands-Sustainable prospecting in Ocean Islands: Biodiversity, Chemistry, Ecology and Biotechnology, Boticario Foundation 1051-20152 Rede Coral Vivo, Brazilian Research Network on Global Climate Change REDEALGAS, Brazilian Research Network on Global Climate Change FAPESC-Foundationinfo:eu-repo/semantics/publishedVersio