Data-driven deep-learning methods for the accelerated simulation of Eulerian fluid dynamics

Deep-learning (DL) methods for the fast inference of the temporal evolution of fluid-dynamics systems, based on the previous recognition of features underlying large sets of fluid-dynamics data, have been studied. Specifically, models based on convolution neural networks (CNNs) and graph neural networks (GNNs) were proposed and discussed. A U-Net, a popular fully-convolutional architecture, was trained to infer wave dynamics on liquid surfaces surrounded by walls, given as input the system state at previous time-points. A term for penalising the error of the spatial derivatives was added to the loss function, which resulted in a suppression of spurious oscillations and a more accurate location and length of the predicted wavefronts. This model proved to accurately generalise to complex wall geometries not seen during training. As opposed to the image data-structures processed by CNNs, graphs offer higher freedom on how data is organised and processed. This motivated the use of graphs to represent the state of fluid-dynamic systems discretised by unstructured sets of nodes, and GNNs to process such graphs. Graphs have enabled more accurate representations of curvilinear geometries and higher resolution placement exclusively in areas where physics is more challenging to resolve. Two novel GNN architectures were designed for fluid-dynamics inference: the MuS-GNN, a multi-scale GNN, and the REMuS-GNN, a rotation-equivariant multi-scale GNN. Both architectures work by repeatedly passing messages from each node to its nearest nodes in the graph. Additionally, lower-resolutions graphs, with a reduced number of nodes, are defined from the original graph, and messages are also passed from finer to coarser graphs and vice-versa. The low-resolution graphs allowed for efficiently capturing physics encompassing a range of lengthscales. Advection and fluid flow, modelled by the incompressible Navier-Stokes equations, were the two types of problems used to assess the proposed GNNs. Whereas a single-scale GNN was sufficient to achieve high generalisation accuracy in advection simulations, flow simulation highly benefited from an increasing number of low-resolution graphs. The generalisation and long-term accuracy of these simulations were further improved by the REMuS-GNN architecture, which processes the system state independently of the orientation of the coordinate system thanks to a rotation-invariant representation and carefully designed components. To the best of the author’s knowledge, the REMuS-GNN architecture was the first rotation-equivariant and multi-scale GNN. The simulations were accelerated between one (in a CPU) and three (in a GPU) orders of magnitude with respect to a CPU-based numerical solver. Additionally, the parallelisation of multi-scale GNNs resulted in a close-to-linear speedup with the number of CPU cores or GPUs.Open Acces

Definition of a New Level One Test Case Measurements of Equilibrium Radiation from an Inductively Coupled Plasma in the Near-UV to Near-IR Spectral Region for a Titan-Type N2-CH4 Mixture. Preliminary Results

A test case, using a similar methodology and experimental set-up than previous test case TC5-Level 1 is presented in this paper. An inductively coupled plasma torch, working at atmospheric pressure, is used to create N2-CH4 Titan-like plasma (98%N2 - 2%CH4). The operating frequency and power are 64 MHz and 3 kW respectively. This kind of apparatus allows obtaining plasma in chemical and quasi-thermal equilibrium The spectral measurements cover the [300-800] nm range and are performed inside the induction coil. Each interesting spectrum is calibrated and compared to the line-by-line spectral code SPARTAN used for the simulation of the radiative emission of entry-type plasma. Finally, a discussion is proposed about the nucleation phenomenon which is occurred in the ICP torch with the N2-CH4 plasma. Preliminary studies show the synthesis of nanostructured carbon on the quartz tube.Comment: Radiation of High Temperature Gases in Atmospheric Entry, Heraklion : Greece (2008

TIPOS DE COMPORTAMIENTOS DE COMPRA UNIVERSITARIOS: CASO SANTA CRUZ DE LA SIERRA- BOLIVIA

The present work has the objective of identifying and describing the university purchasing behavior of the students of the city of Santa Cruz de la Sierra - Bolivia, with the purpose that the universities can direct their marketing efforts in a more effective way. What is more, the aim is to identify the degree or percentage of influence that the marketing stimuli generated by universities have on the decision-making process of student choice. For this purpose, a descriptive research is designed, configuring a self-administered questionnaire, designed on the basis of the Purchase Behavior Model - PDC of Blackwell, Miniard and Engel. The sample is applied to all the private universities in Santa Cruz, being a very significant number. For the analysis, multivariate data analysis is used: factor analysis  techniques, as well as cluster analysis. In the results, it is possibleto identify three types of behaviors, describing and naming for easy identification to each of them with the following names and in the following proportions: The Estimark (8.9%), The Intex (85%) and the Rationals (6.1%). It is concluded that in the decision making of a student by a university, the factors that most influence are the internal ones, such as the characteristics of their personality, and the external factors such as their culture. The marketing stimuli generated by universities barely influence the decision-making process in students (only 8.9%.) These findings, allow to generate future lines of investigationand a greater discussion for the marketing specialists of higher education institutions.El presente artículo tiene el objetivo de identificar y describir el comportamiento de compra universitario de los estudiantes de la ciudad de Santa Cruz de la Sierra – Bolivia, con el propósito de que las universidades puedan dirigir de una manera más efectiva sus esfuerzos de marketing. Asimismo, se busca identificar el grado o porcentaje de influencia que tienen los estímulos de marketing que generan las universidades en la toma de decisiones de elección de los estudiantes. Para este fin, se diseña una investigación descriptiva, configurando un cuestionario auto administrado, diseñado sobre la base del Modelo de Comportamiento de Compra - PDC de Blackwell, Miniard y Engel. La muestra se aplica a las universidades privadasde esa ciudad, siendo un número muy significativo. Para el análisis se recurre al análisis multivariado de datos: las técnicas de análisis factorial y el análisis de clústeres. En los resultados se logran identificar tres tipos de comportamientos: los Estimark (8,9 %), los Intex (85 %) y los Racionales (6,1 %). Se concluye que, en la toma de decisiones de un estudiante por una universidad, los factores que más influyen son los internos, como las características de su personalidad, y también los factores externos, como su cultura. Los estímulos de marketing que generan las universidades apenas influyen en un 8,9 %. Los hallazgos encontrados permiten generar líneas futuras de investigación y una mayor discusión para los especialistas de marketing de estas instituciones

Stress-mediated hyperactivity and anhedonia resistant to diazepam and fluoxetine in Drosophila

Distresses may induce behavioral phenotypes constituting heuristic models for psychopharmacology studies. In several species, including Drosophila, antidepressants counteract stress-induced phenotypes allowing the use of these models to test new psychoactive drugs. Here, we developed a novel and time-efficient protocol to provoke stress-induced phenotypes in Drosophila for the study of psychopharmacological agents. In the first experiment, flies (n = 12/groups) were exposed to a random-sequence of different types of stresses during nearly 24 h (including social isolation, fasting, heat, and electric shock), a protocol named short-term variable stress (SVS). Second, flies were exposed to a single stressful stimulus (social isolation, fasting, heat shock or electric shock, n = 12/groups). Next, flies submitted to SVS protocol were treated with vehicle, diazepam or fluoxetine (n = 12/groups). At the end of the stress protocols, behavioral phenotypes were evaluated in the open field (OF) and sucrose preference tests. In comparison to the unstressed group, flies exposed to SVS exhibited hyperactivity, as well as shorter times exploring the boundaries of the OF. In contrast to fasting stress, SVS reduced sucrose preference in flies. By analyzing the effects of individual stimuli on fly behavior, fasting and electric shock appear to be the predominant influences on the SVS-induced behaviors. Although fluoxetine or diazepam reduced the initial locomotor activity of flies, no treatment prevented the sequelae of SVS. Altogether, this study provides a time-efficient model system for the study of stress-mediated hyperactivity and anhedonia-like state resistant to fluoxetine and diazepam. The applications of SVS in Drosophila to preclinical psychopharmacology require further studies.LAY SUMMARY Exposition to unpredictable stress plays a significant role in psychiatric disorder’s onset. Behavioral traits of these disorders can be partially modeled in rodents aimed at developing psychopharmacological therapies. However, studies in rodents were questioned by ethical issues. Focused on 3Rs principles, we developed a preclinical model for stress and psychopharmacology research in Drosophila. Variable stress induced behavioral alterations, including hyperlocomotion and reduced preference for sucrose in flies. However, behavioral alterations were resistant to fluoxetine and diazepam.Fil: Ramos Hryb, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Ramirez, Mauro Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Lino de Oliveira, Cilene. Universidade Federal de Santa Catarina; BrasilFil: Pagani, Mario Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentin

Plan de Gestión Eléctrica para reducir costos de facturación en el Hospital de Alta Complejidad Virgen de la Puerta Red - Asistencial La Libertad Essalud 2018

El siguiente trabajo de investigación designado: “Plan de gestión eléctrica para reducir costos de facturación en el hospital de alta complejidad Virgen de la Puerta red asistencial la Libertad EsSalud 2018”, cumple con de las políticas de ahorro energético, que promueve el MEM, mediante la Dirección General de Eficiencia Energética, de la misma forma con la norma ISO 14001, en lo concerniente a la conservación de los recursos naturales. El HACVP de Red Asistencial la Libertad EsSalud 2018, es una Institución consagrada a la salud, utilizando diversos equipos biomédicos, iluminación, motores eléctricos, que usan la energía eléctrica para su funcionamiento; es por ello que se plantea un plan de gestión eléctrica para reducir costos de facturación, cuyas acciones planteadas, verificaran su consumo de energía, la eficiencia. Dentro de las tareas a optar, se indica que es necesario implementar un plan de gestión eléctrica, optar por nuevas tecnologías en el sistema de iluminación así como la gestión del cambio de la tarifa eléctrica, el uso adecuado de los transformadores de distribución, Los resultados alcanzados en la indagación se obtuvieron a través de razonamientos técnicos de ingeniería, siendo indispensable además la evaluación económica, la cual se realizó mediante la aplicación de herramientas financieras como el TIR, VAN,PRI, B/C, herramientas que permitieron la evaluación de la rentabilidad del proyecto. Si se lograra implementar las propuestas del estudio, se contaría con plan de gestión energética eléctrica sostenible en el tiempo, según la evaluación realizada se estima un ahorro económico es de S/ 271 068.69 anuales. Finalmente se concluye que de implementarse que las acciones planteadas en el plan de gestión eléctrica estas lograran mejorar la eficiencia del sistema eléctrico, reducir las pérdidas de energía eléctrica, dando como resultado una reducción en los costos de facturación de energía eléctrica

Efectos de abono orgánicos sobre los rendimientos productivos del cultivo del maíz

La investigación se efectuó en una finca del municipio de Siuna RAAN, utilizando un BCA. El mejor rendimiento se logró utilizando como abono el compuesto orgánico denominado bocachi

Pastureland Management, and Influence on the Economic Response of Breeding Herds

The influence of the main pastureland components on the economic response of breeding herds at the Rescate de Sanguily Company was studied from January 2012 to December 2014. Six breeding farms from Ricardo Flores Farm were chosen in the municipality of Jimaguayú, province of Camagüey, Cuba. Variables of pastureland, and forage resources in general were used. To determine the main components that led to variability of breeding units, a Principal Component Analysis was performed; components with values above the unit were selected. Stocking rates variables over 0.60 were chosen too. The elements related with pastureland management in breeding units were defined (forage area with native and cultivated grass), which explain the more than 40 % variance in all the units under the study. Forage balance is negative in the units, as a result of poor agro technical management of grasslands; however, the expensesincome ratio is positive (between CUP $2 500 and$17 600), caused by the low feeding costs. Activities and resources linked to pasture and forage agro techniques must be prioritized, along with the completion of forage areas