Development of thermodynamically consistent machine-learning equations of state: Application to the Mie fluid

A procedure for deriving thermodynamically consistent data-driven equations of state (EoS) for fluids is presented. The method is based on fitting the Helmholtz free energy using artificial neural networks to obtain a closed-form relationship between the thermophysical properties of fluids (FE-ANN EoS). As a proof-of-concept, an FE-ANN EoS is developed for the Mie fluids, starting from a database obtained by classical molecular dynamics simulations. The FE-ANN EoS is trained using first- (pressure and internal energy) and second-order (e.g., heat capacities, Joule–Thomson coefficients) derivative data. Additional constraints ensure that the data-driven model fulfills thermodynamically consistent limits and behavior. The results for the FE-ANN EoS are shown to be as accurate as the best available analytical model while being developed in a fraction of the time. The robustness of the “digital” equation of state is exemplified by computing physical behavior it has not been trained on, for example, fluid phase equilibria. Furthermore, the model’s internal consistency is successfully assessed using Brown’s characteristic curves

STAR: A Computerized Tutorial in General Psychology

This study investigated the use of a computerized tutorial--Self-Test and Review (STAR)--in a computer-managed general psychology course. STAR consists of four major modules which provide the student with a variety of learning exercises, including practice quizzes, practice final exams, performance reviews, and structured study questions. The purpose of the study was to determine whether students would choose STAR as a study tool, the effect of lecture versus self-paced settings on the use of STAR, whether students who used STAR would perform better than those who did not, and the effect of the timing of feedback in STAR on performance. Students were enrolled in either a lecture or self-paced setting. Students in lecture sections met in the classroom for a traditional lecture, discussion, and classroom activities. Students in self-paced sections met in a computer-managed testing center. Analyses of data on course performance and STAR usage indicate that: (1) 49% of the 1,136 subjects used STAR; (2) lecture versus self-paced settings did not affect the use of STAR; (3) the timing of feedback did not have an impact on performance; and (4) students who used the STAR tutorial performed well in the course and, as a whole, better than those students who did not use the tutorial. It is concluded that, while the results were generally positive, the findings of the study create other research questions concerning the impact of modification of lecture settings, the impact of STAR tutorials in other course formats, and the ways in which STAR influences student comprehension

Environmentally induced phenotypic variation in wild yellow-bellied marmots

We thank all the marmoteers who helped in data collection and 2 anonymous reviewers who helped us to clarify our message. AM-C was supported by a Fulbright Fellowship, and JGAM was supported by Fond Québécois de Recherche sur la Nature et les Technologies. KBA was supported by the National Science Foundation between 1962 and 2000. DTB was supported by the National Geographic Society, UCLA (Faculty Senate and the Division of Life Sciences), a Rocky Mountain Biological Laboratory research fellowship, and by the National Science Foundation (IDBR-0754247 and DEB-1119660 to DTB as well as DBI 0242960 and 0731346 to the Rocky Mountain Biological Laboratory).Peer reviewedPostprin

Human cones appear to adapt at low light levels: Measurements on the red—green detection mechanism

AbstractRecent physiological evidence suggests that cones do not light adapt at low light levels. To assess whether adaptation is cone-selective at low light levels, the red-green detection mechanism was isolated. Thresholds were measured with a large test flash, which stimulated the L and M cones in different fixed amplitude ratios, on different colored adapting fields. Thresholds were plotted in L and M cone contrast coordinates. The red-green mechanism responded to an equally-weighted difference of L and M cone contrast on each colored field, demonstrating equivalent, Weberian adaptation of the L and M cone signals. The L and M cone signals independently adapted for illuminance levels as low as 60 effective trolands (e.g. M-cone trolands. Since this adaptation is entirely selective to cone type, it suggests that the cones themselves light-adapt. The red-green detection contour on reddish fields was displaced further out from the origin of the cone contrast coordinates, revealing an additional sensitivity loss at a subsequent, spectrally-opponent site. This second-site effect may arise from a net “red” or “green” signal that represents the degree to which the L and M cones are differently hyperpolarized by the steady, colored adapting field. Such differential hyperpolarization is compatible with equivalent, Weberian adaptation of the L and M cones

Risk Assessment Due to Debris Flows in Paz de Río-Colombia

Paz de Río is an important economic area of Colombia where iron mines produce most of the mineral for the steel production in the country. Along the La Chapa creek some debris flows have occurred since 1963 producing economic losses and human deaths at Santa Teresa village. Economical losses are related to disruption of the main access to La Chapa iron mine facilities, and flooding of Paz de Río due to damming of Chicamocha River, the main drainage system of the region, which is blocked by debris flows. The local authority for Natural Disaster Management (CREPAD) jointly with the Universidad Nacional de Colombia carries out the risk evaluation related to potential debris flows along the creek. The study models the debris flow using the FLO2D software considering the geological, geomorphologic, topographic and hydrological setting of the area. As main sediment source we considered the potential volume of material supplied by a large landslide at the upper part of the creek basin, known locally as the Mesa Alta landslide, whereas sediment production due to landslides within the basin was considered as point inflows along the creek. Physical vulnerability was evaluated by using the Leone (1999) approach, which considers the flow height and its relation with the structure height, whereas social vulnerability was evaluated by considering factors as population density, people age, literacy level and economical income. Risk assessment was based on the Liu and Lei (2003) approach in which risk is defined graphically considering critical threshold curves obtained from vulnerability and hazard values. Risk for different elements within the influence area of the creek was evaluated and mitigation measures including engineering works were proposed, the influence of these measures on hazard and risk was also evaluated

Associação entre participação em programa de assistência alimentar e sobrepeso

OBJETIVO Investigar associação entre participação no programa de assistência alimentar e sobrepeso/obesidade, segundo nível de pobreza. MÉTODOS Estudo transversal com dados sobre 46.217 mulheres não gestantes e não lactantes, de Lima, Peru, obtidos de pesquisas, com representatividade nacional, nos anos de 2003, 2004, 2006 e 2008-2010. A variável dependente foi o sobrepeso/obesidade e a independente foi a participação no programa de assistência alimentar. Utilizou-se regressão de Poisson; os modelos foram estratificados por nível socioeconômico familiar para todo o país, por área de residência (Lima versus o resto do país; urbano versus residência rural) e anos de estudo (2003-2006 versus 2008-2010). Os modelos foram ajustados por idade, nível acadêmico, urbanização e ano de estudo. RESULTADOS Participar do programa de assistência alimentar associou-se com risco aumentado de sobrepeso/obesidade para as mulheres que viviam em domicílios sem indicadores de pobreza (PR = 1,29; IC95% 1,06;1,57). Quando estratificados por área de residência, foram observadas associações similares para as mulheres que vivem em Lima e em áreas urbanas; não foram encontradas associações entre a participação no programa de assistência alimentar e sobrepeso/obesidade entre as mulheres que vivem fora de Lima ou em áreas rurais, independentemente de sua condição de pobreza. CONCLUSÕES Participar do programa de assistência alimentar associou-se com sobrepeso/obesidade para mulheres não pobres. Estudos adicionais serão necessários em países que enfrentam ambas as faces da má nutriçã[email protected] The objective of this study was to investigate the association between food assistance program participation and overweight/obesity according to poverty level. METHODS A cross-sectional analysis of data from 46,217 non-pregnant and non-lactating women in Lima, Peru was conducted; these data were obtained from nationally representative surveys from the years 2003, 2004, 2006, and 2008-2010. The dependent variable was overweight/obesity, and the independent variable was food assistance program participation. Poisson regression was used to stratify the data by family socioeconomic level, area of residence (Lima versus the rest of the country; urban versus rural), and survey year (2003-2006 versus 2008-2010). The models were adjusted for age, education level, urbanization, and survey year. RESULTS Food assistance program participation was associated with an increased risk of overweight/obesity in women living in homes without poverty indicators [prevalence ratio (PR) = 1.29; 95% confidence interval (CI) 1.06;1.57]. When stratified by area of residence, similar associations were observed for women living in Lima and urban areas; no associations were found between food assistance program participation and overweight/obesity among women living outside of Lima or in rural areas, regardless of the poverty status. CONCLUSIONS Food assistance program participation was associated with overweight/obesity in non-poor women. Additional studies are required in countries facing both aspects of malnutrition.Revisión por pare

Associação entre participação em programa de assistência alimentar e sobrepeso

OBJECTIVE The objective of this study was to investigate the association between food assistance program participation and overweight/obesity according to poverty level. METHODS A cross-sectional analysis of data from 46,217 non-pregnant and non-lactating women in Lima, Peru was conducted; these data were obtained from nationally representative surveys from the years 2003, 2004, 2006, and 2008-2010. The dependent variable was overweight/obesity, and the independent variable was food assistance program participation. Poisson regression was used to stratify the data by family socioeconomic level, area of residence (Lima versus the rest of the country; urban versus rural), and survey year (2003-2006 versus 2008-2010). The models were adjusted for age, education level, urbanization, and survey year. RESULTS Food assistance program participation was associated with an increased risk of overweight/obesity in women living in homes without poverty indicators [prevalence ratio (PR) = 1.29; 95% confidence interval (CI) 1.06;1.57]. When stratified by area of residence, similar associations were observed for women living in Lima and urban areas; no associations were found between food assistance program participation and overweight/obesity among women living outside of Lima or in rural areas, regardless of the poverty status. CONCLUSIONS Food assistance program participation was associated with overweight/obesity in non-poor women. Additional studies are required in countries facing both aspects of malnutrition.OBJETIVO Investigar associação entre participação no programa de assistência alimentar e sobrepeso/obesidade, segundo nível de pobreza. MÉTODOS Estudo transversal com dados sobre 46.217 mulheres não gestantes e não lactantes, de Lima, Peru, obtidos de pesquisas, com representatividade nacional, nos anos de 2003, 2004, 2006 e 2008-2010. A variável dependente foi o sobrepeso/obesidade e a independente foi a participação no programa de assistência alimentar. Utilizou-se regressão de Poisson; os modelos foram estratificados por nível socioeconômico familiar para todo o país, por área de residência (Lima versus o resto do país; urbano versus residência rural) e anos de estudo (2003-2006 versus 2008-2010). Os modelos foram ajustados por idade, nível acadêmico, urbanização e ano de estudo. RESULTADOS Participar do programa de assistência alimentar associou-se com risco aumentado de sobrepeso/obesidade para as mulheres que viviam em domicílios sem indicadores de pobreza (PR = 1,29; IC95% 1,06;1,57). Quando estratificados por área de residência, foram observadas associações similares para as mulheres que vivem em Lima e em áreas urbanas; não foram encontradas associações entre a participação no programa de assistência alimentar e sobrepeso/obesidade entre as mulheres que vivem fora de Lima ou em áreas rurais, independentemente de sua condição de pobreza. CONCLUSÕES Participar do programa de assistência alimentar associou-se com sobrepeso/obesidade para mulheres não pobres. Estudos adicionais serão necessários em países que enfrentam ambas as faces da má nutrição

La universidad y la técnica

Una especie de abismo se abrió desde un principio entre la universidad, sus inquietudes, sus orientaciones y sus glorias académicas y el mundo de nuestras gentes en su mayoría campesinas, que a puro músculo y con un espíritu colectivo ejemplar se dieron a la tarea de dominar el ambiente geográfico y echar las bases de una economía auténtica y nacional. Esta ha sido en mi sentir la raíz de todos los males que se han anotado a la universidad y la razón de su fracaso cuando a los problemas palpitantes de la realidad del país le ha tocado hacerle frente. Mientras en el siglo pasado y aun en el presente las gentes campesinas de Colombia abrían trochas y caminos, extraíanrudimentariamente el oro de las minas y sin elementos, sin técnica, sin organización y sin estímulos bien conducidos en medio de un ambiente económicamente colonial, arraigaban la industria cafetera, explotaban la quina y el caucho, extendían el tabaco en lucha constante con los agentes del gobierno, estructuraban una industria de caña de azúcar, luchaban por extraer la subsistencia personal y nacional de los aromáticos granos del cacao, reemplazaban montes y selvas por dehesas y ganados y erigían las espigasdel maíz como emblema auténtico de su vida colectiva mientras que la universidad se encastillaba en altas y meticulosas consideraciones sobre extraños y complicados problemas. El contacto de las gentes con la universidad apenas se establecía cuando el hijo del campesino lograba incorporarse en ella en un mundo tan diferente del de los suyos, o cuando los universitarios por elemental llamado revolucionario de sus mentes y de su sangre unían sus gritos de rebelión a los gritos de los campesinos en los campos de las guerras civiles después de las cuales sin haber logradonada practico, retornaba la universidad a su castillo de marfil y el campesino más pobre y agotado sin armas de lucha volvía a su terca brega por subsistir por crear riquezay por incorporar sus esfuerzos al patrimonio nacional