Fixed grid finite element analysis for 3D structural problems

Fixed Grid (FG) methodology was first introduced by García and Steven as an engine for numerical estimation of two-dimensional elasticity problems -- The advantages of using FG are simplicity and speed at a permissible level of accuracy -- Two dimensional FG has been proved effective in approximating the strain and stress field with low requirements of time and computational resources -- Moreover, FG has been used as the analytical kernel for different structural optimisation methods as Evolutionary Structural Optimisation, Genetic Algorithms (GA), and Evolutionary Strategies -- FG consists of dividing the bounding box of the topology of an object into a set of equally sized cubic elements -- Elements are assessed to be inside (I), outside (O) or neither inside nor outside (NIO) of the object -- Different material properties assigned to the inside and outside medium transform the problem into a multi-material elasticity problem -- As a result of the subdivision NIO elements have non-continuous properties -- They can be approximated in different ways which range from simple setting of NIO elements as O to complex noncontinuous domain integration -- If homogeneously averaged material properties are used to approximate the NIO element, the element stiffness matrix can be computed as a factor of a standard stiffness matrix thus reducing the computational cost of creating the global stiffness matrix. An additional advantage of FG is found when accomplishing re-analysis, since there is no need to recompute the whole stiffness matrix when the geometry changes -- This article presents CAD to FG conversion and the stiffness matrix computation based on non-continuous elements -- In addition inclusion/exclusion of O elements in the global stiffness matrix is studied -- Preliminary results shown that non-continuous NIO elements improve the accuracy of the results with considerable savings in time -- Numerical examples are presented to illustrate the possibilities of the metho

Una evaluación de línea base múltiple de la terapia de aceptación y compromiso centrada en pensamiento negativo repetitivo en trastorno por pánico

Although cognitive-behavioral therapy (CBT) is efficacious for treating panic disorder, a segment of the population is not treated due to the treatment length and the acceptability of interoceptive exposure. This study explored the efficacy of a brief protocol based on acceptance and commitment therapy (ACT) focused on repetitive negative thinking (RNT) in adults suffering from panic disorder. We designed a 4-session RNT-focused ACT protocol because previous CBT studies considered this length "ultra-brief." Additionally, although conducting exposure is consistent with the ACT model, we did not include explicit exposure exercises to increase the intervention acceptability. A randomized, multiple-baseline design across three participants was implemented with a 3-month follow-up. The effect of the intervention was evaluated through weekly scores on the Depression Anxiety and Stress Scale – 21 (DASS-21; S. H. Lovibond & P. F. Lovibond, 1995), Penn State Worry Questionnaire (PSWQ; Meyer et al., 1990), and the frequency of panic attacks. After the intervention, all participants ceased to experience panic attacks and showed clinically significant changes in the DASS-Total and PSWQ. The effect sizes comparable across designs were very large and statistically significant for the DASS-Total (d= 2.48), DASS-Depression (d= 1.45), DASS-Anxiety (d= 1.93), DASS-Stress (d= 1.63), and PSWQ (d= 2.36). All three participants also showed clinically significant changes and large effect sizes in experiential avoidance (d= 3.26), cognitive fusion (d= 3.58), and valued living (Progress: d= 0.72, Obstruction: d= 2.43). In conclusion, brief RNT-focused ACT interventions might be efficacious for treating panic disorder.Aunque la terapia cognitivo-conductual (TCC) es eficaz en el trastorno de pánico, un segmento de la población no recibe tratamiento debido a su duración y aceptabilidad de la exposición interoceptiva. Este estudio exploró la eficacia de la terapia de aceptación y compromiso (ACT) focalizada en pensamiento negativo repetitivo (PNR) en adultos con trastorno por pánico. Se diseñó un protocolo de 4 sesiones porque estudios previos han considerado esta duración como "ultra breve". Pese a que la exposición es consistente con el modelo ACT, no incluimos ejercicios de exposición explícita para aumentar la aceptabilidad de la intervención. Se implementó un diseño de línea de base múltiple aleatorizado a través de tres participantes con un seguimiento de 3 meses. El efecto de la intervención se evaluó con la Depression Anxiety and Stress Scale - 21 (DASS-21, S. H. Lovibond y P. F. Lovibond, 1995), el Penn State Worry Questionnaire (PSWQ; Meyer et al., 1990) y la frecuencia de ataques de pánico. Tras la intervención, los tres participantes dejaron de experimentar ataques de pánico y mostraron cambios clínicamente significativos en DASS-Total y PSWQ. Los tamaños del efecto comparables a través de diseños fueron muy grandes y estadísticamente significativos para DASS-Total (d = 2.48), DASS-Depresión (d = 1.45), DASS-Ansiedad (d = 1.93), DASS-Estrés (d = 1.63) y PSWQ (d = 2.36). Los participantes mostraron cambios clínicamente significativos y grandes tamaños del efecto en evitación experiencial (d = 3.26), fusión cognitiva (d = 3.58) y valores (Progreso: d = 0.72, Obstrucción: d = 2.43)

Agroecología y el diseño de sistemas agrícolas resilientes al cambio climático

Diverse, severe and location-specific impacts on agricultural production are anticipated with climate change.Temperature and water availability remain key factors in determining crop growth and productivity, predicted changes in these factors will lead to reduced crop yields. Climate induced changes in insect pest, pathogen and weed population dynamics and invasiveness could compound such effects. Undoubtedly climate and weather induced instability will affect levels of and access to food supply. Changes that will not radically modify the monoculture nature of dominant agroecosystems may temporarily moderate negative impacts. The biggest and most durable benefits will likely result from more radical agroecological measures that will strengthen the resilience of farmers and rural communities, such as diversification of agroecosytems in the form of polycultures, agroforestry systems and crop-livestock mixed systems accompanied by organic soil management, water conservation and harvesting and general enhancement of agrobiodiversity. Traditional farming systems are repositories of a wealth of principles and measures that can help modern agricultural systems become more resilient to climatic extremes. Many of these agroecological strategies that reduce vulnerabilities to climate variability include, crop diversification, maintaining local genetic diversity, animal integration, soil organic management, water conservation and harvesting, etc. Understanding the agroecological features that underlie the resilience of traditional agroecosystems is an urgent matter, as they can serve as the foundation for the design of adapted agricultural systems. Field surveys and results reported in the literature suggest that agroecosystems are more resilient when inserted in a complex landscape matrix, featuring adapted local germplasm deployed in diversified cropping systems managed with organic matter rich soils and water conservation-harvesting techniques. The identification of systems that have withstood climatic events recently or in the past and understanding the agroecological features of such systems that allowed them to resist and/or recover from extreme events is of increased urgency, as the derived resiliency principles and practices that underlie successful farms can be disseminated to thousands of farmers.Se anticipa que el cambio climático cause impactos sobre la producción agrícola que serán diversos, severos y específicos según la ubicación geográfica. La temperatura y la disponibilidad de agua siguen siendo factores clave que determinan el crecimiento de los cultivos y la productividad. Los cambios predichos en estos factores causarán una baja en el rendimiento de los cultivos. Los cambios inducidos por el clima en cuanto a las dinámicas de población de plagas de insectos, patógenos y malezas y su invasividad podrían agravar los efectos mencionados. Sin duda alguna, la inestabilidad inducida por el clima y el tiempo afectará los niveles de producción de alimentos y el abastecimiento de los mismos. Los cambios para la adaptación que no modifiquen radicalmente la naturaleza dominante del monocultivo podrían moderar temporalmente los impactos negativos. Los beneficios mayores y más duraderos provendrán de medidas agroecológicas más radicales que fortalezcan la resiliencia de los agricultores y las comunidades rurales, tales como la diversificación de los agroecosistemas en forma de policultivos, los sistemas agroforestales y los sistemas que combinen la agricultura con la ganadería, acompañados por el manejo orgánico de los suelos, la conservación y la cosecha de agua y un incremento general de la agrobiodiversidad. Los sistemas agrícolas tradicionales son depósitos de abundantes principios y medidas que pueden ayudar a que los sistemas agrícolas modernos se vuelven más resilientes a los extremos climáticos. Muchas de las estrategias agroecológicas tradicionales que reducen la vulnerabilidad a la variabilidad climática incluyen la diversificación de cultivos, el mantenimiento de la diversidad genética local, la integración de los animales, la adición de materia orgánica al suelo, la cosecha de agua, etc. Urge entender las características agroecológicas que son la base de la resiliencia de los agroecosistemas tradicionales, ya que de ahí se pueden derivar principios útiles que sirvan de base para el diseño de sistemas agrícolas adaptados. Los estudios sobre el terreno y los resultados reportados en la literatura sugieren que los agroecosistemas son más resilientes cuando están insertados en una matriz de paisaje compleja, que incluya germoplasma local adaptado utilizado en sistemas de cultivos diversificados manejados con suelos ricos en materia orgánica y técnicas de conservación-cosecha de agua. Los principios y prácticas de resiliencia en los que se basan las fincas exitosas pueden ser difundidos a miles de agricultores a través de redes campesino a campesino para ampliar las prácticas agroecológicas que incrementan la resiliencia de los agroecosistemas

Medical geography in the study of hepatitis A, in the Coffee-triangle region, Colombia, 2007-2011

Objectives: There are few studies of geographical characterization of viral hepatitis. For this reason, we after estimating the incidence rates for Hepatitis A (HAV), we developed epidemiological GIS-based maps for this viral disease, within a well-defined geographic region (the coffee triangle) in Colombia. Study design: A retrospective cross-sectional analysis of surveillance data and GIS-based developing of epidemiological maps. Methods: Surveillance cases data (2007-2011) were used to estimate annual incidence rates using reference population data, on hepatitis, to develop the first maps of HAV in the 53 municipalities of the coffee-triangle region of Colombia (departments Caldas, Quindio, Risaralda). GIS used was Kosmo® 3.1. To summarize and compare the data among municipalities and departments (as units of analysis) we generate indicators such as accumulated incidence rates (AIR) and incidence rates ratios. Results: 1518 HAV cases were reported, 47% from Quindío, 30% Caldas and 22% Risaralda. Quindio presented with the highest AIR (131.54) among all the administrative units under study (Caldas, AIR: 46.39; Risaralda, AIR: 37.62). Interestingly, the highest rates in Quindio, during the period, could be related to the increased number of cases reported in two municipalities from 2008 (Quimbaya, AIR ratio: 4.0 and Montenegro: 3.61). The causes that underlie this augmentation will be subject to further research. Conclusions: Incidence rates for HAV is still high in the region. Showing epidemiological data, particularly in maps would allow planning actions oriented to interventions at the different forms of transmission that this disease has, which is highly important for decisions in public health policies

Petrography and application of the rietveld method to the quantitative analysis of phases of natural clinker generated by coal spontaneous combustion

Fine-grained and mainly reddish color, compact and slightly breccious and vesicular pyrometamorphic rocks (natural clinker) are associated to the spontaneous combustion of coal seams of the Cerrejón Formation exploited by Carbones del Cerrejón Limited in La Guajira Peninsula (Caribbean Region of Colombia). These rocks constitute remaining inorganic materials derived from claystones, mudstones and sandstones originally associated with the coal and are essentially a complex mixture of various amorphous and crystalline inorganic constituents. In this paper, a petrographic characterization of natural clinker, aswell as the application of the X-ray diffraction (Rietveld method) by mean of quantitative analysis of its mineral phases were carried out. The RIQAS program was used for the refinement of X ray powder diffraction profiles, analyzing the importance of using the correct isostructural models for each of the existing phases, which were obtained from the Inorganic Crystal Structure Database (ICSD). The results obtained in this investigation show that the Rietveld method can be used as a powerful tool in the quantitative analysis of phases in polycrystalline samples, which has been a traditional problem in geology

Liquid crystals and their defects

These lecture notes discuss classical models of liquid crystals, and the different ways in which defects are described according to the different models.Comment: CIME lecture course, Cetraro, 201

In Vitro and In Vivo Efficacy of Ether Lipid Edelfosine against Leishmania spp. and SbV-Resistant Parasites

Leishmaniasis represents a major international health problem, has a high morbidity and mortality rate, and is classified as an emerging and uncontrolled disease by the World Health Organization. The migration of population from endemic to nonendemic areas, and tourist activities in endemic regions are spreading the disease to new areas. Unfortunately, treatment of leishmaniasis is far from satisfactory, with only a few drugs available that show significant side-effects. Here, we show in vitro and in vivo evidence for the antileishmanial activity of the ether phospholipid edelfosine, being effective against a wide number of Leishmania spp. causing cutaneous, mucocutaneous and visceral leishmaniasis. Our experimental mouse and hamster models demonstrated not only a significant antileishmanial activity of edelfosine oral administration against different wild-type Leishmania spp., but also against parasites resistant to pentavalent antimonials, which constitute the first line of treatment worldwide. In addition, edelfosine exerted a higher antileishmanial activity and a lower proneness to generate drug resistance than miltefosine, the first drug against leishmaniasis that can be administered orally. These data, together with our previous findings, showing an anti-inflammatory action and a very low toxicity profile, suggest that edelfosine is a promising orally administered drug for leishmaniasis, thus warranting clinical evaluation

Agroecology and the design of climate change resilient farming systems

Se anticipa que el cambio climático cause impactos sobre la producción agrícola que serán di- versos, severos y específicos según la ubicación geográfica. La temperatura y la disponibilidad de agua siguen siendo factores clave que determinan el crecimiento de los cultivos y la productivi- dad. Los cambios predichos en estos factores causarán una baja en el rendimiento de los cultivos. Los cambios inducidos por el clima en cuanto a las dinámicas de población de plagas de insectos, patógenos y malezas y su invasividad podrían agravar los efectos mencionados. Sin duda alguna, la inestabilidad inducida por el clima y el tiempo afectará los niveles de producción de alimentos y el abastecimiento de los mismos. Los cambios para la adaptación que no modifiquen radical- mente la naturaleza dominante del monocultivo podrían moderar temporalmente los impactos negativos. Los beneficios mayores y más duraderos provendrán de medidas agroecológicas más radicales que fortalezcan la resiliencia de los agricultores y las comunidades rurales, tales como la diversificación de los agroecosistemas en forma de policultivos, los sistemas agroforestales y los sistemas que combinen la agricultura con la ganadería, acompañados por el manejo orgánico de los suelos, la conservación y la cosecha de agua y un incremento general de la agrobiodiversidad. Los sistemas agrícolas tradicionales son depósitos de abundantes principios y medidas que pue- den ayudar a que los sistemas agrícolas modernos se vuelven más resilientes a los extremos cli- máticos. Muchas de las estrategias agroecológicas tradicionales que reducen la vulnerabilidad a la variabilidad climática incluyen la diversificación de cultivos, el mantenimiento de la diversidad genética local, la integración de los animales, la adición de materia orgánica al suelo, la cosecha de agua, etc. Urge entender las características agroecológicas que son la base de la resiliencia de los agroecosistemas tradicionales, ya que de ahí se pueden derivar principios útiles que sirvan de base para el diseño de sistemas agrícolas adaptados. Los estudios sobre el terreno y los resultados reportados en la literatura sugieren que los agroecosistemas son más resilientes cuando están insertados en una matriz de paisaje compleja, que incluya germoplasma local adaptado utilizado en sistemas de cultivos diversificados manejados con suelos ricos en materia orgánica y técnicas de conservación-cosecha de agua. Los principios y prácticas de resiliencia en los que se basan las fincas exitosas pueden ser di- fundidos a miles de agricultores a través de redes campesino a campesino para ampliar las prác- ticas agroecológicas que incrementan la resiliencia de los agroecosistemas.ABSTRACT: Diverse, severe and location-specific impacts on agricultural production are anticipated with climate change. Temperature and water availability remain key factors in determining crop growth and productivity, predicted changes in these factors will lead to reduced crop yields. Climate in- duced changes in insect pest, pathogen and weed population dynamics and invasiveness could compound such effects. Undoubtedly climate and weather induced instability will affect levels of and access to food supply. Changes that will not radically modify the monoculture nature of dominant agroecosystems may temporarily moderate negative impacts. The biggest and most durable benefits will likely result from more radical agroecological measures that will strengthen the resilience of farmers and rural communities, such as diversification of agroecosytems in the form of polycultures, agroforestry systems and crop-livestock mixed systems accompanied by organic soil management, water conservation and harvesting and general enhancement of agro- biodiversity. Traditional farming systems are repositories of a wealth of principles and measures that can help modern agricultural systems become more resilient to climatic extremes. Many of these agroecological strategies that reduce vulnerabilities to climate variability include, crop diversification, maintaining local genetic diversity, animal integration, soil organic management, water conservation and harvesting, etc. Understanding the agroecological features that underlie the resilience of traditional agroecosystems is an urgent matter, as they can serve as the foun- dation for the design of adapted agricultural systems. Field surveys and results reported in the literature suggest that agroecosystems are more resilient when inserted in a complex landscape matrix, featuring adapted local germplasm deployed in diversified cropping systems managed with organic matter rich soils and water conservation-harvesting techniques. The identification of systems that have withstood climatic events recently or in the past and understanding the agroecological features of such systems that allowed them to resist and/or recover from extreme events is of increased urgency, as the derived resiliency principles and practices that underlie suc- cessful farms can be disseminated to thousands of farmers

FIXED GRID FINITE ELEMENT ANALYSIS FOR 3D STRUCTURAL PROBLEMS

Fixed Grid (FG) methodology was first introduced by Garcia and Steven as an engine for numerical estimation of two-dimensional elasticity problems. The advantages of using FG are simplicity and speed at a permissible level of accuracy. Two-dimensional FG has been proved effective in approximating the strain and stress field with low requirements of time and computational resources. Moreover, FG has been used as the analytical kernel for different structural optimization methods as Evolutionary Structural Optimization, Genetic Algorithms (GA), and Evolutionary Strategies. FG consists of dividing the bounding box of the topology of an object into a set of equally sized cubic elements. Elements are assessed to be inside (I), outside (O) or neither inside nor outside (NIO) of the object. Different material properties assigned to the inside and outside medium transform the problem into a multi-material elasticity problem. As a result of the subdivision NIO elements have non-continuous properties. They can be approximated in different ways which range from simple setting of NIO elements as O to complex non-continuous domain integration. If homogeneously averaged material properties are used to approximate the NIO element, the element stiffness matrix can be computed as a factor of a standard stiffness matrix thus reducing the computational cost of creating the global stiffness matrix. An additional advantage of FG is found when accomplishing re-analysis, since there is no need to recompute the whole stiffness matrix when the geometry changes. This article presents CAD to FG conversion and the stiffness matrix computation based on non-continuous elements. In addition inclusion/exclusion of O elements in the global stiffness matrix is studied. Preliminary results shown that non-continuous NIO elements improve the accuracy of the results with considerable savings in time. Numerical examples are presented to illustrate the possibilities of the method

Revisión de las especies del género \u3ci\u3eEurybia\u3c/i\u3e [Illiger, 1807] de Colombia y descripción de nuevos taxa (Lepidoptera: Riodinidae)

Se revisan las especies del género Eurybia Illiger (Lepidoptera: Riodinidae) de Colombia en base al estudio de especimenes depositados en colecciones nacionales publicas y privadas. Como resultado se analizaron 20 taxones y se describen como nuevas a: E. chocoensis nueva especie, E. dardus atlantica nueva subespecie, E. molochina violacea nueva subspecie, E. rubeolata nielseni nueva subspecie y E. rubeolata rufomarginata nueva subspecie. Eurybia dardus fassli Seitz, 1916, E. franciscana caerulescens Druce, 1904 y E. dardus mestiza Salazar, Villalobos y Vargas, 2021 son restituidos a nivel subespecífico. Se crea la nueva combinación de E. rubeolata silaceana basado en el estudio de su órganos genitales. Lo anterior permite con­cluir que Colombia es uno de los países con mayor riqueza de especies de Eurybia de la región neotropical. The species of the genus Eurybia Illiger [(1807)] (Lepidoptera: Riodinidae) present in Colombia are reviewed. The specimens deposited in several official and private national collections were studied, resulting in the presence of 20 taxa and the description of one species and four subspecies. The new taxa described cor­respond to: Eurybia chocoensis new species, E. dardus atlantica new subspecies, E. molochina violacea new subspecies, E. rubeolata nielseni new subspecies and E. rubeolata rufomarginata new subspecies. Eurybia dardus fassli Seitz, 1916, E. franciscana caerulescens Druce, 1904 and E. dardus mestiza Salazar, Villalobos and Vargas, 2021 are restored at the subspecific level. The new combination E. rubeolata silaceana is created based on the study of its genitalia. The information obtained allows us to conclude that Colombia is one of the countries with the greatest richness of Eurybia species in the Neotropical region