3,148 research outputs found
Evolución histórica de los vehÃculos aéreos no tripulados hasta la actualidad
The origin and development of unmanned aviation has been almost matched that of manned aviation, starting both from an almost common point. As in conventional manned aviation, military applications, have been the motor of technological development and the potential applications of these types of systems throughout much of the twentieth century and early twenty-first century. Finally it has been in relatively recent times that these systems are experiencing an impressive boom due to the discovery of the wide variety of commercial and civil operations that are able to perform very effectively. This paper attempts to summarize the historical evolution that these systems have suffered and in the end, to present a quick analysis of the major civil / commercial applications, trying to provide an overview of the main types of systems, their classification and general configuration.Peer Reviewe
Estimation of effective diffusion coefficient and its effect on effectiveness factor for hds catalytic process: a multi-scale approach
Effectiveness factors have great relevance in multiphase reactors modeling since they are the conventional way of incorporating the effects of intra-particle resistance reaction rate. This work determines the description level effect of catalytic pellet microstructure on mass and energy effective transport coefficients prediction, isothermal and no isothermal. For such a purpose some results about on evaluation of the effective diffusivity and conductivity with the methodology of volume averaging were applied. The obtained results along with a Langmuir–Hinshelwood/Hougen–Watson kinetic expression were applied to establish the concentration and temperature fields in a catalytic particle. The evaluation of concentration field and effectiveness factors were developed using two different models: pseudohomogeneous mass and energy transport model for a catalytic particle with reaction in all domain, and heterogeneous mass and energy transport model with fluid-catalytic surface interphase reaction for a realistic porous structure model. The results show the differences in concentration and temperature profiles between both models and consequently in effectiveness factors. This could be ascribed to the form of evaluation of effective transport coefficients used in the pseudo-homogeneous model, and presumably to the simple shape of the unit cells used for the solution of the closure problem for the average transport equations with homogeneous reaction
Tuning a hybrid SA based algorithm applied to Optimal Sensor Network Design
El problema de diseño de una red de sensores en plantas de proceso (Sensor Network Design Problem, SNDP) consiste en determinar las variables de proceso que deben ser medidas, a fin de alcanzar el grado de conocimiento requerido de dicha planta. Proponemos resolver el problema SNDP en plantas de tamaño y complejidad creciente utilizando un algoritmo hÃbrido basado en Recocido Simulado (Hybrid Simulated Annealing, HSA) como metaheurÃstica principal y Búsqueda Tabú con Oscilación Estratégica como metaheurÃstica subordinada. Investigamos los ajustes de los parámetros de control para obtener el mejor desempeño del HSA. Los resultados experimentales indican que el HSA puede efectivamente encontrar una solución de buena calidad en tiempos de computo razonable. Mas a ´ un, HSA muestra buenas ´ caracterÃsticas en la solución de SNDP en comparación con algoritmos propuestos en la literatura.Sensor network design problem (SNDP) in process plants includes the determination of which process variables should be measured to achieve a required degree of knowledge about the plant. We propose to solve the SNDP problem in plants of increasing size and complexity using a hybrid algorithm based on Simulated Annealing (HSA) as main metaheuristic and Tabu Search embedded with Strategic Oscillation (SOTS) as a subordinate metaheuristic. We studied the tuning of control parameters in order to improve the HSA performance. Experimental results indicate that a high-quality solution in reasonable computational times can be found by HSA effectively. Moreover, HSA shows good features solving SNDP compared with proposals from the literature.Fil: Hernandez, Jose Luis. Universidad Nacional de RÃo Cuarto. Facultad de IngenierÃa; ArgentinaFil: Salto, Carolina. Universidad Nacional de la Pampa. Facultad de IngenierÃa. Departamento de Informatica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Minetti, Gabriela Fabiana. Universidad Nacional de la Pampa. Facultad de IngenierÃa. Departamento de Informatica; ArgentinaFil: Carnero, Mercedes del Carmen. Universidad Nacional de RÃo Cuarto. Facultad de IngenierÃa; ArgentinaFil: Bermudez, Carlos Alberto. Universidad Nacional de la Pampa. Facultad de IngenierÃa. Departamento de Informatica; ArgentinaFil: Sanchez, Mabel Cristina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - BahÃa Blanca. Planta Piloto de IngenierÃa QuÃmica. Universidad Nacional del Sur. Planta Piloto de IngenierÃa QuÃmica; Argentin
Ileal apparent and standardized amino acid digestibility of soybean and colza meal in diets for finishing pigs
Agri-food chains generate by-products such as soybean and colza meal for animal feed. Their nutritional value is variable and should be analysed for better quality control before their inclusion in balanced diets. The objective was to determine the content and ileal apparent and standardized digestibility of protein and amino acids (AA) of soybean (PS) and colza meal (PC) as a source of protein in diets for finishing pigs. The experimental units were arranged in a 3×3 Latin square design repeated. The treatments (T) were T1: PS+corn starch, T2: PC+corn starch, and T3: corn starch (Control), which were randomly assigned to six pigs cannulated in distal ileum (PV 75±1.2 kg). The variables were contents and apparent ileal and standardized ileal digestibility of amino acids in soybean and colza meal. To determine digestibility, chromic oxide was added to the diets. The protein and fat contents were higher in the soybean meal. Ash, crude fibre, neutral detergent fibre, acid detergent fibre, phosphorus and calcium contents were higher in the colza meal. Essential amino acid content was higher in soybean meal, but methionine was higher in colza meal. Apparent ileal digestibility (DIA) of total amino acids was similar (p > 0.05) among protein ingredients; but for lysine and threonine it was higher (p ≤ 0.05) in soybean meal, except methionine. Methionine DIA was 89.78 %, 3.88 % higher (p ≤ 0.05) in colza meal. Standardized ileal digestibility (DIE) of total amino acids was similar (p > 0.05) among ingredients, but lysine and threonine were higher (p ≤ 0.05) in soybean meal. DIE was different (p ≤ 0.05) among ingredients for all amino acids except methionine. Ileal and standardized digestibility of all amino acids were higher in soybean meal, except methionine, which was higher in colza meal. The DIA of total amino acids was similar in both protein ingredients, except lysine and threonine in soybean meal and methionine in colza meal
Efecto de 2 y 4 meses de práctica de fútbol en el desarrollo osteogénico de niños prepuberales
Football for children and young people has been used as a tool to improve health and prevent future diseases. The aim of this study was to investigate, the effect of 2- and 4-month participation in an osteogenic sport such as football on the variables of bone mineral content and bone mineral density in pre-pubertal children. Twenty under-10 children (9.5 ± 1.4 years old) who were doing football training 3 hours a week and were at the Tanner I stage were included. Bone mineral density and bone mineral content values were measured using a dual energy X-ray absorber. The results showed an increase in the values of bone mineral content and total bone mineral density after two months of practice (p<0.05; TE: 0.11 and TE: 0.27 respectively), significantly higher values after four months of practice compared to the initial value and the value after two months (p<0.05; TE: 0.40 and TE: 0.13 respectively). Significant increase in bone mineral content and bone mineral density in the legs after two and four months of practice (p<0.05; TE: 0.43 and TE: 0.40 respectively). Our data suggest that a 2- and 4-month recreational football training programme is beneficial for the osteogenic development and health of children during the pre-pubertal stage.El fútbol en edad infantil o juvenil se ha utilizado como una herramienta para mejorar la salud y prevenir futuras enfermedades. El objetivo de este estudio fue investigar) el efecto de la participación de 2 y 4 meses en un deporte osteogénico como el fútbol en las variables de contenido mineral óseo y densidad mineral ósea en niños prepuberales. Se incluyeron 20 niños de categorÃa sub-10 (9,5 ± 1,4 años) que realizaban entrenamiento de fútbol 3 horas a la semana y se encontraban en la etapa de Tanner I. Los valores de densidad mineral ósea y contenido mineral óseo se midieron mediante un absorciómetro de rayos X de doble energÃa. Los resultados mostraron un incremento de los valores de contenido mineral óseo y densidad mineral ósea total tras los dos meses de práctica (p<0,05; TE: 0,11 y TE: 0,27 respectivamente), valores significativamente mayores tras cuatro meses de práctica en comparación con el valor inicial y el valor tras dos meses (p<0,05; TE: 0,40 y TE: 0,13 respectivamente). Aumento significativo de contenido mineral óseo y densidad mineral ósea en las piernas a los dos y cuatro meses de práctica (p<0,05; TE: 0,43 y TE: 0,40 respectivamente). Los datos sugieren que un programa de entrenamiento de fútbol recreativo de 2 y 4 meses es beneficioso para el desarrollo osteogénico y la salud de los niños durante la etapa prepuberal
Versatile Graphene-Based Platform for Robust Nanobiohybrid Interfaces
Technologically useful and robust graphene-based interfaces for devices
require the introduction of highly selective, stable, and covalently bonded
functionalities on the graphene surface, whilst essentially retaining the
electronic properties of the pristine layer. This work demonstrates that highly
controlled, ultrahigh vacuum covalent chemical functionalization of graphene
sheets with a thiol-terminated molecule provides a robust and tunable platform
for the development of hybrid nanostructures in different environments. We
employ this facile strategy to covalently couple two representative systems of
broad interest: metal nanoparticles, via S-metal bonds, and thiol-modified DNA
aptamers, via disulfide bridges. Both systems, which have been characterized by
a multi-technique approach, remain firmly anchored to the graphene surface even
after several washing cycles. Atomic force microscopy images demonstrate that
the conjugated aptamer retains the functionality required to recognize a target
protein. This methodology opens a new route to the integration of high-quality
graphene layers into diverse technological platforms, including plasmonics,
optoelectronics, or biosensing. With respect to the latter, the viability of a
thiol-functionalized chemical vapor deposition graphene-based solution-gated
field-effect transistor array was assessed
Preliminary report on the July 10–11, 2015 explosive eruption at Volcán de Colima: Pyroclastic density currents with exceptional runouts and volume
http://dx.doi.org/10.1016/j.jvolgeores.2015.11.022Reporte preliminar acerca de una de las últimas etapas eruptivas de Volcán de Colima, análisis realizado a partir de técnicas de percepción remotaOn July 10–11, 2015 an eruption occurred at Colima volcano produced 10.5 km long pyroclastic density currents (PDCs) along the Montegrande, and 6.5 km long along the San Antonio ravines. The summit dome was destroyed and a new crater excavated and breached to the south. This new breach connects to a narrow channel that descends along Colima's southern flank and was used by a subsequent lava flow. The Montegrande PDCs represent the longest and hottest flow of this type recorded during the past 30 years but are still smaller in comparison to the 15-km long PDCs produced during the 1913 Plinian eruption. Data obtained from field reconnaissance, lahar monitoring stations, and satellite imagery suggest that at least six PDCs occurred. The two largest PDCs (H/L 0.2) were able to surmount topographic barriers or bends. Based on field reconnaissance and digital elevation models extracted from SPOT satellite imageries we estimate a minimum volume for the valley-pond and distal fan deposits of 4.5 × 106 m3. After one week, the deposits were still hot with burning trees on the surface and millimeter-sized holes from which fumes were emanating. The juvenile components of the deposits consist of gray dense blocks and vesicular dark-gray blocks and bombs with bread-crust textures and cooling joints. The mineral association of these rocks consists of plagioclase + clinopyroxene + orthopyroxene + FeTi-oxides ± olivine and resorbed hornblende in a dark glassy matrix that corresponds to an andesitic composition.CONACY
Virtual research and learning communities in Latin America : The CEVALE2VE case
New strategies for the adaptation of higher scientific education to the requirements of the network society are briefly discussed, in particular the pivotal role played by virtual research and learning communities in the Latin American region. The Centro Virtual de Altos Estudios de Altas Energias (CEVALE2VE) is singled out in reference to the virtual graduate course on particle physics that was given at several Venezuelan and Colombian national universities and research institutions during the semesters September 2014 - February 2015 and March 2016 - July 2016. Different course implementation aspects are reviewed to encourage and facilitate similar regional initiatives in the near future.Peer reviewe
Shoc2/Sur8 Protein Regulates Neurite Outgrowth
The Shoc2 protein has been implicated in the positive regulation of the Ras-ERK pathway by increasing the functional binding interaction between Ras and Raf, leading to increased ERK activity. Here we found that Shoc2 overexpression induced sustained ERK phosphorylation, notably in the case of EGF stimulation, and Shoc2 knockdown inhibited ERK activation. We demonstrate that ectopic overexpression of human Shoc2 in PC12 cells significantly promotes neurite extension in the presence of EGF, a stimulus that induces proliferation rather than differentiation in these cells. Finally, Shoc2 depletion reduces both NGF-induced neurite outgrowth and ERK activation in PC12 cells. Our data indicate that Shoc2 is essential to modulate the Ras-ERK signaling outcome in cell differentiation processes involved in neurite outgrowth.This work was supported by FIS grant (PI10/00815) to JLO; CIBERNED to MC; SAF2008-01951, Comunidad Autónoma de Madrid (CAM) S-SAL-0202-2006-01 and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) to TI; FIS grant PI12/00775 and ISCIII-RETIC (Red Temática de Investigación Cooperativa en Cáncer) RD12/0036/0027 from the Instituto de Salud Carlos III to PSG; and FIS grants (PI09/0562 and PI13/00703), ISCIII-RETIC (RD06/0020/0003 and RD12/0036/0021), and the Spanish Association Against Cancer (AECC) to JMR. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S
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