Inestabilidad de placas plegadas prismáticas. Por el método de bandas finitas

El método de bandas finitas se emplea para determinar cargas de bifurcación de láminas plegadas prismáticas apoyadas en diafragmas en sus extremos. La formulación de estabilidad es de tipo energético y permite tratar tanto cargas sólidas como líquidas, incluyendo la influencia del movimiento de un líquido en modos de inestabilidad torsional. Se presentan ejemplos numéricos para evaluar convergencia de la solución y aplicaciones a problemas de inestabilidad torsional de vigas de pared delgada. Estudios paramétricos realizados sobre un ejemplo permiten comparar distintas formas de sección transversal en su comportamiento en pandeo.Peer Reviewe

Monitoreo de la humedad edáfica en cultivos de arándanos en el pedemonte del sistema de Tandilia

Godoy, Carlos A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Departamento de Producción Vegetal, Suelos e Ingeniería Rural. Cátedra de Fruticultura. Balcarce, Buenos Aires, Argentina.33-37El arándano es un cultivo sensible al estrés hídrico, por lo que resulta fundamental monitorear el contenido de humedad del suelo durante todo su ciclo. El objetivo de este trabajo fue construir modelos característicos de retención de humedad bajo condiciones de campo en distintos sectores de un lote cultivado con arándanos. Para ello, se estimó la humedad volumétrica con una sonda de reflectometría en el dominio temporal o TDR (del inglés “Time Domain Reflectometry”), y el potencial mátrico con tensiómetros. Las mediciones se realizaron en un lote de arándanos plantado en un suelo Argiudol típico en fase fuertemente inclinada, característico de la unidad geomorfológica serrana de la región pampeana, en el que se identificaron dos sectores con diferente textura a profundidad de raíces, franca en el más bajo, y franco-arcillosa en el más alto. La relación entre el potencial mátrico y el contenido de humedad del suelo mostró un comportamiento lineal dentro del rango de potenciales evaluados, habiéndose generado modelos de retención hídrica diferentes para cada sector del lote. Se puso en evidencia que los tensiómetros presentaron mayor precisión en el sector de textura franca

Biochar and zeolites did not improve phosphorus uptake or crop productivity in a field trial performed in an irrigated intensive farming system

Soil conditioners, such as biochar and zeolites, may play an important role in agriculture if they increase nutrient use efficiency, in particular, that of phosphorus (P), due to the depletion of phosphate rocks from which P-fertilizers are manufactured. This study report results from a field trial, where maize was grown in summer and oats in winter, and from a pot experiment with maize. In the field, the use of biochar and zeolites, along with an untreated control in combination with various P rates (0, 50, 100 and 200 kg P2O5 ha−1), was tested. In the pot experiment, six treatments were included, biochar, zeolites and a non-amended control with and without P application. Soil conditioners did not significantly influence tissue elemental composition or the dry matter (DM) yield of maize and oats in the field trial, nor the DM yield of maize in the pots. In the field trial, average maize DM yields varied from 14.3 to 15.6 t ha−1 and 11.8 to 13.7 t ha−1 and average oats DM yields from 2.1 to 2.4 t ha−1 and 3.0 to 3.2 t ha−1, respectively, in 2018 and 2019. Biochar only significantly increased total organic carbon (C); and zeolites the levels of potassium (K) in the soil, a result of their initial composition. P application increased DM yield of maize in the second year and oats in the two years of the field trial and also the DM yield of potted maize. In the pots, P application also influenced the concentration of P and several other nutrients in plant tissues and increased the labile soil P fraction. This study showed that the biochar and zeolite soil conditioners applied may not be suitable for short-term increase of crop production in soil with high agricultural potential and under intensive irrigated farming systems.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and European Regional Development Fund (ERDF) under Programme PT2020 for financial support to Centro de Investigação de Montana (CIMO) (UID/AGR/00690/2015) and Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB) (UIDB/04033/2020).info:eu-repo/semantics/publishedVersio

PROPUESTA ECONÓMICA DE AJUSTE AL SALARIO MÍNIMO EN PANAMÁ: 2021

The economic analysis of the adjustment to the minimum wage in Panama includes a historical journey from 1959 to 2021, for this, the information generated by the National Institute of Statistics and Census was used, integrating those of the Ministry of Labor and Development. Labor and the International Labor Organization. The analysis from the economic point of view used indicators that allow us to know the reality and lead to the conclusion that the biannual adjustments to the salary do not improve the level of well-being of the population and do not increase the consumption or purchasing power of the workers. For the study period, 16 executive decrees and two laws that set the minimum wage were established, which evolved since 1959, for qualified labor of B/.0.50 per hour and B/.103.99 per month; until reaching 2021, from B/. 2.76 per hour and B/.574.93 per month. A valuable source of information was the 2018 Income and Expenditure Survey, which establishes that Panamanian households allocate 17.7% of their expenses to food and 82.30% to satisfy the rest of their needs for housing, clothing, health, transportation, education, recreation, among others. Using the Engel Coefficient, which observes the existence of a close relationship between spending and the level of household income; It is concluded that the adjustment of the Minimum Wage must be 20.76%, to cover the needs of households that amount to B/.1,388.72 per month.El análisis económico del ajuste al salario mínimo en Panamá incluye un recorrido histórico a partir de 1959 hasta el 2021, para ello, se utilizó fundamentalmente la información generada por el Instituto Nacional de Estadística y Censo, integrando las del Ministerio de Trabajo y Desarrollo Laboral y la Organización Internacional del Trabajo.    El análisis desde el punto de vista económico manejó indicadores que permiten conocer la realidad y llevan a concluir que los ajustes bianuales al salario no mejoran el nivel de bienestar de la población y tampoco aumenta el consumo o poder de compra de los trabajadores. Para el periodo de estudio se establecieron 16 decretos ejecutivos y dos leyes que fijan el salario mínimo, los cuales evolucionaron desde 1959, para mano de obra calificada de B/.0.50 por hora y de B/.103.99 mensuales; hasta llegar al 2021, de B/. 2.76 por hora y B/.574.93 mensuales. Una valiosa fuente de información fue la Encuesta de Ingresos y Gastos de 2018 que establece que los hogares panameños destinan el 17.7% de sus gastos a alimentación y el 82.30% para satisfacer el resto de sus necesidades de vivienda, vestimenta, salud, transporte, educación, recreación, entre otros. Utilizando el Coeficiente de Engel, que observa la existencia de una relación estrecha entre el gasto y el nivel de ingreso de los hogares; se concluye que el ajuste del Salario Mínimo debe ser del 20.76%, para cubrir las necesidades de los hogares que ascienden a B/.1,388.72 mensuales

RECOMENDACIONES PARA LA TRANSFORMACIÓN DEL PERFIL PRODUCTIVO DE PANAMÁ POSPANDEMIA

The article is a look at the productive profile of Panama, which since its conception was designed to favorminorities since its operation generates deep distortions, which over time have been sustained by the number of subsidies; but that with the pandemic it has collapsed and that the country needs to develop a new development model with a change in its profile or productive matrix, with a focus on sustainability, equity, gender, inclusive and allows care for the environment; because it is not about generating a higher per capita income but about reducing the gap of inequality, poverty, extreme poverty throughalternatives that are not the government subsidy, already today in the region, Panama, is one of the three countries with the highest inequality, surpassed only by Brazil and Colombia; and it is one of the nine countries with the worst income distributionin the world compared to countries in Africa.In the analysis of the economic and productive profile of Panama, there are significant changes in the weight of the main branches of economic activity in the post-pandemic GDP; variations in the composition and behavior of exports and imports; the composition and trends of the energy and electrical matrix; the main environmental impacts of economic activities and the perspectives and indicators of competitiveness, productivity, chain and added value of productive activities. Finally, it culminates with the identification of the sectors with potential for the transformation of the productive profile with social inclusion, gender equality and environmental sustainability, with a view to the elaboration of a development plan for 2050.En el análisis del perfil económico y productivo de Panamá, se evidencian la existencia cambios significativos en el peso de las principales ramas de actividad económica en el PIB pospandemia; variaciones en la composición y comportamiento de las exportaciones e importaciones; la composición y tendencias de la matriz energética y eléctrica; los principales impactos ambientales de las actividades económicas y las perspectivas e Indicadores de competitividad, productividad, encadenamiento y valor agregado de las actividades productivas. Finalmente, culmina con la identificación de los sectores con potencialidad para la transformación del perfil productivo con inclusión social, equidad de género y sustentabilidad ambiental, con la mirada de la elaboración de un plan de desarrollo al 2050

New record of Podilymbus podiceps (Linnaeus, 1758) (Podicipediformes, Podicipedidae) in the Patagonian region of southern Chile

We report a new record of Podilymbus podiceps (Linnaeus, 1758) in the southern Chilean Patagonia, 120 km south of previous records on the western side of the Andes, and more than 400 km south of their known distribution area on the eastern side of the Andes. This is the southernmost record of this species in Chile and one of the southernmost records worldwide, highlighting the vagrancy of this species in southern Patagonia

Un prototipo de plataforma de ciudades inteligentes : Aplicación para la protección ciudadana en el departamento de Godoy Cruz

Como objetivo general se propone implementar una plataforma de Ciudad Inteligente en el departamento de Godoy Cruz, Mendoza, destinada a la seguridad ciudadana. Se propone recolectar datos a través de la interconexión de redes de sensores inalámbricos (WSN), que serán utilizados para integrar la plataforma de Ciudad Inteligente. La integración de WSN y Cloud Computing da lugar a infraestructuras denominadas Cloud de Sensores, las cuales pueden aplicarse a ciudades inteligentes. En este proyecto se propone aplicar una plataforma de gestión de Cloud de Sensores a aplicaciones de monitoreo y seguridad en ciudades inteligentes. Para este propósito, se adaptará una plataforma de gestión de Cloud de Sensores denominada Sensor Cirrus, la cual está destinada actualmente a agricultura de precisión. Esta plataforma ofrecerá nuevas soluciones a la comuna de Godoy Cruz, ya que brindará información para estudiar la problemática delictiva y mejorar la seguridad en la comuna. En general se espera contar con un modelo para la implementación de ciudades inteligentes apto para ser implementado en el departamento de Godoy Cruz o similares, que contribuya a solucionar problemas tales como la inseguridad.Eje: Arquitectura, Redes y Sistemas Operativos.Red de Universidades con Carreras en Informática (RedUNCI

Optimization of electrophoretic separations of thirteen phenolic compounds using single peak responses and an interactive computer technique

An interactive computer method is proposed for the electrophoretic separation of 13 phenolic compounds from extra-virgin olive oil using single peak response values. A central composite design was executed for optimization of the sodium tetraborate concentration, pH and applied voltage. Statistical models were determined for eight resolution responses and thirteen effective mobilities. Six of the resolution models had highly significant ANOVA lack of fit values, limiting their accuracies for use in Derringer´s desirability function search for optimal separation conditions. None of the 13 effective mobility models suffered from significant lack of fit. Since it is not possible to define effective mobility target values for the desirability function, an interactive computer program developed in our laboratories was applied to the single peak models. Mouse or cursor movements were executed to define experimental conditions in model simulations of the electropherogram. These simulations resulted in superior peak separations, especially for the apigenin and luteolin peaks, in 35 min, compared with those obtained in close to 50 min with the resolution models. Verification experiments performed 2 and 3 years later confirmed the robustness of the models.Um método computacional interativo foi desenvolvido para a separação eletroforética de 13 compostos fenólicos de azeite de oliva extravirgem, usando valores individuais de resposta para cada pico. Um planejamento composto central foi executado para a otimização da concentração de tetraborato de sódio, pH e voltagem aplicada. Foram determinados modelos estatísticos para oito respostas de resolução e treze de mobilidades efetivas. Seis modelos de resolução apresentaram significativa falta de ajuste após ANOVA, o que limitou sua acurácia para uso nas funções de desejabilidade de Derringer-Suich na busca pelas condições ótimas de separação. Nenhum dos 13 modelos de mobilidade efetiva apresentou falta de ajuste significativa. Visto que não foi possível definir valores alvos para as funções de desejabilidade, um programa de computador interativo, desenvolvido em nossos laboratórios, foi aplicado aos modelos individuais de cada pico. Movimentos do mouse ou do cursor foram executados para definir as condições experimentais nas simulações dos eletroferogramas. Essas simulações resultaram em uma melhor separação dos picos, especialmente para os picos de apigenina e luteolina, em 35 min, comparado aos obtidos para cerca de 50 min com os modelos de resolução. Experimentos de verificação executados 2 e 3 anos depois confirmaram a robustez dos modelos.17441753Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES