Abstract A neural network and a genetic algorithm were used in a hybrid method to get the optimal design parameters of an Agave angustifolia Haw. green leaf shredder. First, a prototype of an experimental machine was built using the design parameters recommended by the literature and calculated using linear equations. Then, the shredder prototype was subjected to experiments. The defibration data with different blade adjustments were obtained with experimental values. The data was configured and trained with an artificial neural network to establish a correlation between the defibration quality and the design parameters. The multi-objective optimization method based on genetic algorithms determined the optimal design parameters of the shredder’s functional mechanical elements. The best point was obtained from the least number of broken fibers (2.83%) and the most waste (73.15%). The method used proved suitable to optimize the design parameters; this was based on actual data obtained by experiments performed with the prototype and then modeled through artificial intelligence methods such as neural networks to determine an optimal solution using evolutionary genetic algorithm methods.

ABSTRACT Stargardt's disease and the flavimaculatus fund are variants of the same nosological entity. They constitute the most frequent juvenile macular dystrophy and common cause of central vision loss in adults under 50 years of age. A 35-year-old female patient who was diagnosed with Stargardt's disease currently suffers from low visual capacity. We present findings of a localized macular lesion in the foveal region of the bronzed and pale aspect in the temporal region of the optic papilla. At the histological level, a cluster of lipofuscin-like material is produced in the cells of the retinal pigment epithelium by the mutation of the ABCA4 gene. The incidence of Stargardt disease is around one person affected by 10,000 people and usually affects adolescents and young adults under 20 years old.

RESUMEN La enfermedad de Stargardt y el fondo flavimaculatus son variantes de una misma entidad nosológica, que constituyen la distrofia macular juvenil más frecuente, y una causa común de pérdida de visión central en adultos menores de 50 años. Se trata de una paciente femenina de 35 años con enfermedad de Stargardt, atendida en una unidad básica avanzada en salud del municipio de Vila Nova do Piauí, Brasil, que actualmente presenta baja capacidad visual. Se presenta una lesión macular localizada en la región foveal, de aspecto bronceado y pálido en la región temporal de la papila óptica. A nivel histológico, se produce un cúmulo de material tipo lipofuscina en las células del epitelio pigmentario de la retina, por la mutación del gen ABCA4. La incidencia de la enfermedad de Stargardt se sitúa alrededor de una persona afectada entre 10 000 y suele afectar a adolescentes y adultos jóvenes.

Abstract The article takes as its point of reference some Marta Sanz's works –the essay No tan incendario (2014) and some of her novels: Animales domésticos (2003), Black, black, black (2010), Un buen detective no se casa jamás (2012), Daniela Astor y la caja negra (2013) y Farándula (2015)– in order to study the fundamental characteristics of her literatura and, specially, the importance of the commitment, of the fight against hegemonic thinking and of the critical attitude.

Resumen A través del análisis del ensayo No tan incendiario (2014) y de algunas de sus principales novelas –Animales domésticos (2003), Black, black, black (2010), Un buen detective no se casa jamás (2012), Daniela Astor y la caja negra (2013) y Farándula (2015)–, el artículo expone algunas de las características de la literatura de Marta Sanz, referidas, fundamentalmente, a la forma en la que a través de ella se canaliza una actitud comprometida y crítica que intenta oponerse a los discursos dominantes que emanan desde los focos de poder.

Introduction: The first permanent molar is a fundamental tooth to determine the mastication pattern during the whole life, it is vital to develop and maintain a proper occlusion. Objective: describing the premature loss of the first permanent molar. Materials and Methods: an observational, descriptive and transversal study was carried out in the primary school Antonio López Coloma in the area of Mexico neighborhood in Colon municipality, Matanzas province, in the period from January to March 2015, in 169 children 6 to 11 years old. They were study variable, age, sex and the location of the missing tooth. Results: the 3 % of the students lost the first permanent molar, the 40 % of 11 years old boys loss this tooth. The girls represented the 60 % of the studied. Conclusions: The investigated mainly the female sex in the age of 11 lost the first permanent molar very early. The left lower first molar had the highest incidence.

Introducción: el primer molar permanente es un diente fundamental al determinar el patrón de masticación durante toda la vida y desempeñar un papel primordial para desarrollar y mantener una oclusión apropiada. Objetivo: describir la pérdida prematura del primer molar permanente. Materiales y Métodos: se realizó estudio observacional, descriptivo, transversal en la escuela primaria “Antonio López Coloma” del Consejo popular México, del municipio Colón, provincia Matanzas, en el periodo comprendido de enero a marzo del 2015 en 169 niños las edades 6 a 11 años. Se estudiaron variables como: edad sexo, y localización del molar ausente. Resultados: el 3% de los estudiados perdió el primer molar permanente, el 40 % de niños con 11 años tuvo pérdida de este diente, las féminas representaron el 60 % de los estudiados. Conclusiones: los estudiados en la edad de 11 años con predominio del sexo femenino presentaron pérdida prematura del primer molar permanente, en los que resaltó el primer molar inferior izquierdo.

This study analysed the association between character strengths and happiness and global health in adolescents by gender. The participants comprised 117 high-school students (μ =16.90, σ =.81) from Málaga (Spain). All participants completed the Values in Action 120-Items Questionnaire (VIA-120), the 12-Item General Health Questionnaire (GHQ-12), and the Happiness Item. The results showed higher levels of character strengths and lower levels of temperance and religiousness in the humanity score. Moderately significant associations were found between all character strengths and general health, happiness, and especially hope. Boys had significantly higher scores on zest, prudence, self-regulation, and hope (Student t test). The study suggests that character strengths could contribute to increased life satisfaction and health among adolescents.

El presente estudio examina las fortalezas psicológicas propuestas por el Modelo VIA (Values In Action) en adolescentes, y sus relaciones con la felicidad y la salud mental, considerando las diferencias de sexo. La muestra estuvo constituida por 117 estudiantes de bachillerato (μ =16.90, σ =.81) de Málaga, quienes completaron el Cuestionario de Fortalezas Humanas (VIA-120), el Cuestionario de Salud General (GHQ-12) y el Ítem único de Felicidad. Los resultados muestran un predominio de las fortalezas incluidas en el valor de humanidad, en detrimento de las de templanza y la fortaleza espiritualidad. Se hallaron correlaciones moderadas entre todas las fortalezas del valor trascendencia con la felicidad y la salud mental, encontrándose la correlación más fuerte entre dichas variables con la fortaleza optimismo. Por otro lado, se han observado en los varones medias superiores a las mujeres en vitalidad, prudencia, autorregulación y optimismo. El estudio corrobora que las fortalezas son recursos psicológicos que favorecen otras características positivas, siendo el sexo una variable que influye en los resultados.

RESUMO A idade Chapadmalalan (Plioceno) é caracterizada por uma grande diversidade dos Glyptodontidae. A maioria dos táxons é reconhecida a partir de carapaças dorsais parciais e/ou tubos caudais, enquanto que as principais características diagnósticas estão relacionadas com a morfologia particular das superfícies expostas dos osteodermas. Algumas espécies são importantes sob o ponto de vista biogeográfico. O Chapadmalalan Superior é baseado na biozona de Paraglyptodon chapadmalensis. Uma reavaliação do material tipo e referido, aliado a novos achados procedentes das formações Chapadmalal e El Polvorín, indica que a diversidade de Glyptodontidae é menor do que se supunha. A morfologia particular das superfícies expostas dos osteodermas utilizada para a caracterização de algumas espécies na realidade se deve a alterações tafonômicas, que resultaram em um padrão de ornamentação não real. Assim, o Glytodontinae P. chapadmalensis deve ser substituído como fóssil guia, uma vez que nem essa espécie nem as incluídas nos gêneros Urotherium, Trachycalyptus e Lomaphorus são bem caracterizadas. Levando-se em conta a diversidade dos Glyptodontidae para esse intervalo, os Glyptodontinae são muito raros (contrastando com a sua abundância no Pleistoceno), enquanto que Eosclerocalyptus, "Plohophorini" (Plohophorus) e Doedicurinae (cf. Eleutherocercus antiquus) são os táxons mais registrados.

ABSTRACT A large diversity of Glyptodontidae has been proposed as characterizing the Chapadmalalan Age (Pliocene). Most of these taxa were recognized on the basis of partial dorsal carapaces and/or caudal tubes, whereas the main diagnostic characteristic is a particular morphology of the exposed surface of the osteoderms. From a biostratigraphic point of view some species are biostratigraphically important. The Upper Chapadmalalan is based on the Paraglyptodon chapadmalensis biozone. Both the re-evaluation of the type and referred materials and new significant findings from the Chapadmalal and El Polvorín Formations indicate that the diversity of Pliocene Glyptodontidae is more limited than previously supposed. The particular morphology of the exposed surface of the osteoderms that characterizes some of the species actually corresponds to a taphonomic alteration, which results in a non-real ornamentation pattern. Thus, the Glyptodontinae P. chapadmalensis must be replaced as a fossil guide because neither this species nor the species included in the genera Urotherium, Trachycalyptus and Lomaphorus are well characterized. Taking into account the diversity of Glyptodontidae for this lapse, the Glyptodontinae are very scarce (a situation that contrasts with its records in the Pleistocene), whereas Eosclerocalyptus, "Plohophorini" (Plohophorus) and Doedicurinae (cf. Eleutherocercus antiquus) are among the most recorded taxa.

The decomposition of the solid solution of potassium jarosite with chromium(VI) in Ca(OH)2 media was studied in the present work. According to experimental results, the incorporation of CrO42- into the crystal structure of jarosite resulted in a solid solution with the following approximate formula: [K0.86(H3O)0.14]Fe2.67[(SO4)1.23(CrO4)0.77][(OH)5.01(H2O)0.99]. The experimental data describe a reaction based on the shrinking core model with chemical control for spherical particles. A reaction order of n = 0.67 and an activation energy (Ea) of 63.75 kJ mol-1 were obtained in the induction period (tind). The progressive conversion period is characterized by the diffusion of K+, SO42- and CrO42- ions into the solution. In this stage, n = 1.99 with respect to OH-, and Ea = 51.56 kJ mol-1. The CrO42- diffusion is slower compared to that of sulfate, a slight amount of chromate is adsorbed in the layer of the solid residue consisting on Fe(OH)3. Finally, the equations that satisfactorily describe the reaction process were established from the data obtained.

Background: periodontal diseases are frequent affections among the population of Cuba and around the world. Young people diagnosed with chronic gingivitis predominate in the municipality of Colon, Province of Matanzas; therefore it is necessary to study the risk factors allowing designing and elaborating working and educative strategies. Aim: to identify risk factors related with chronic gingivitis among young people aged 15-18 years. Materials and methods: an observational, cross-sectional, descriptive study was carried out in the period January-April 2013 in a universe of 370 school students. The universe was totally studied. The studied variables were the following: demographic, risk factors and level of knowledge. The oral examination was carried out with a classification set and periodontal explorer in a mobile dental chair. The obtained results were expressed in tabular form using absolute numbers and percentages. The participation in the study was approved through informed consent. Outcomes: female sex predominated over the male one in 57.8 %; 83.3 % of the male studied students were affected; the deficient oral hygiene was present in 70.3 % of the cases, followed by smoking with 12.4 %. 71.7 % of the students had an unsatisfactory level of knowledge. Conclusions: there was a predominance of the female in the studied universe. Most of the male students had gingivitis. The deficient oral hygiene and smoking were the main related factors. An unsatisfactory level of knowledge predominated.

Introducción: las enfermedades periodontales son afecciones frecuentes en la población del mundo y de Cuba. En el municipio Colón, de la provincia de Matanzas, predominan jóvenes con diagnóstico de gingivitis crónica, lo que hace necesario el estudio de factores de riesgo, que permitan diseñar y elaborar estrategias de trabajo y de tipo educativas. Objetivo: identificar los factores de riesgos relacionados con la gingivitis crónica en jóvenes de 15 a 18 años. Materiales y métodos: se realizó un estudio observacional, descriptivo, transversal, en los meses de enero-abril 2013, en un universo de 370 escolares. Se estudiaron las siguientes variables: demográficas, factores de riesgo y nivel de conocimiento. En un sillón móvil se realizó examen bucal con set de clasificación y sonda periodontal. Los resultados obtenidos se expresaron en forma tabular, con el uso de cifras absolutas y porcentaje. La entrada al estudio fue aprobada mediante el consentimiento informado. Resultados: el sexo femenino predominó en 57,8 % sobre el masculino; el 83,3 % de los estudiantes masculinos se encontró afectado; la higiene bucal deficiente se reflejó en el 70,3 %, seguida del tabaquismo con 12,4 %. El 71,7 % presentó un nivel no satisfactorio de conocimiento. Conclusiones: las féminas predominaron en correspondencia con el universo estudiado. Los varones en su mayoría presentaron gingivitis. La higiene bucal deficiente y el tabaquismo se destacan entre los factores de riesgo relacionados. Predominó un nivel insatisfactorio de conocimiento.

The first permanent molar is one of the most important dental structures for the development of a physiologic occlusion and an adequate masticatory function; these teeth play an important role in the development and maintenance of an appropriate dental occlusion; they are very predisposed to dental caries after their eruption, around the age of 6 years. A cross-sectional, descriptive, observational study was carried out in the school Rene Fraga Moreno, of Colon municipality, province of Matanzas, with the aim of determining the first permanent molar lost in children aged 6-12 years, in the period from November 2012 to January 2013. The universe were 395 schoolchildren aged 6-12 years; the sample was composed by 41 children, with at least the lost of one of the four first molars. As a result there it was the prevalence of children aged 12 years, with the absence of the first molars, representing 31, 7 %; the male gender was the most represented one with 65, 8 %, and the 12 years age group presented 61, 5 % of students with inadequate buccal hygiene. We observed that 87, 8 % of the studied schoolchildren had a cariogenic diet; the more frequently absent first molar was the first right low molar with 60. 9 %. The male gender was the most affected by this disorder. The inadequate buccal hygiene predominated. The cariogenic diet prevailed in all ages. The first right low molar was the most frequently found lost in the mouth of these children.

El primer molar permanente es una de las estructuras dentarias más importantes para el desarrollo de una oclusión fisiológica y una adecuada función masticatoria, estos dientes desempeñan un papel primordial en el desarrollo y mantenimiento de una oclusión dentaria apropiada, son muy susceptibles a la caries dental, después de su erupción, alrededor de los 6 años. Se realizó un estudio observacional, descriptivo, transversal en la escuela René Fraga Moreno del municipio Colón, provincia de Matanzas con el objetivo de determinar la pérdida del primer molar permanente en los niños de 6 a 12 años, en el periodo comprendido de noviembre del 2012 a enero del 2013. El universo fue 395 estudiantes comprendidos en las edades 6-12 años, la muestra la conformaron 41 niños con,al menos, la pérdida de uno de los cuatro primeros molares. Como resultado, prevalecieron los de 12 años, con los primeros molares ausentes, representando el 31.7 %; el sexo masculino fue el más representado con 65,8 %, el grupo de edad de 12 años presentó un 61.5 % de estudiantes con higiene bucal inadecuada. Se observó que un 87.8 % de los estudiantes estudiados consumían dieta cariogénica, el primer molar que más ausente se encontró en la boca de estos niños fue el primer molar inferior derecho con 60.9 %. Esta afección afectó más al sexo masculino. Predominó la higiene bucal inadecuada. En todas las edades prevaleció la dieta cariogénica. El primer molar inferior derecho fue el que más se ausentó en la boca de estos niños.

The used sample was a solid plumbojarosite-argentian jarosite-hydronium jarosite solution. The stoichiometry of the alkaline decomposition and cyanide reaction in alkaline medium were studied. Alkaline decomposition shows an induction period, as well as a conversion period. Results on the reaction order and activation energy are consistent with the spherical particle model with decreasing core and chemical control. Six partial models and three global models were developed in order to describe its basic behavior. In every case the models were validated and tested for a plumbojarosite conversion of X = 0.75

La muestra utilizada es una solución sólida de plumboja-rosita-arjentojarosita-hidroniojarosita. Se estudió la estequiometría de la reacción de descomposición y la de cianuración en medio alcalino. La descomposición alcalina muestra un periodo de inducción y un periodo de conversión. Los resultados de orden de reacción y energía de activación son consistentes con el modelo de núcleo decreciente y control químico. Se desarrollaron seis modelos parciales y tres modelos globales para describir su comportamiento básico. En todos los casos los modelos fueron validados y probados para una conversión de plumbojarosita de X = 0.75.

We carried out a cross sectional, descriptive, observational study in patients assisting the odontological clinic of Píritu, Falcon State, Venezuela, in the period from June to December 2011, who were dental caries urgencies; the aim was identifying caries behavior in ages from 4 to 12 years; dental caries were classified according to the lesions location and deepness; the most frequently found acute pulpy pathologies, and the risk factors were diagnosed. With a directed sample of 160 children, the information was obtained using different techniques, like patients and relatives questioning, extra oral and intra oral observation, groping, and teeth exploration and percussion. As a result we found a higher percent of the male gender and the age group from 7 to 9 years; most of the cases were transitory pulp diseases, and the most affected teeth sides were the occlusal sides and surface dentina; the most common risk factors associated to caries appearing were dental bacterial plaque and cariogenic diet.

Se realizó un estudio observacional, descriptivo y transversal en los pacientes que acudieron a la clínica odontológica de Píritu, estado Falcón, Venezuela, en el período de junio a diciembre de 2011, y resultaron ser urgencia por caries dental. Con el objetivo de identificar el comportamiento de la misma, en las edades de 4 a 12 años, se clasificó la caries dental según localización y profundidad de las lesiones, se diagnosticó las patologías pulpares agudas encontradas con mayor frecuencia, y los factores de riesgo. Con una muestra dirigida de 160 niños; la información se obtuvo a través de diferentes técnicas, tales como: interrogatorio a pacientes y familiares, observación clínica extraoral e intraoral, palpación, exploración y percusión de los dientes. Como resultados se obtuvieron: mayor porcentaje en el sexo masculino y en el grupo 7 a 9 años, mayor aporte de los casos la pulpitis transitoria, donde las caras de los dientes más afectadas resultaron las caras oclusales y dentina superficial, los factores de riesgo más relacionados con la aparición de la caries, fueron placa dentobacteriana y dieta cariogénica.

This paper studies and determines the dispersion properties (Jg, Eg and Db), kinetics parameters and hydrodynamics of the process and its effect on the recovery of silver contained in spent diluted fixers by techniques of ion flotation in columns. The experimental results show silver recoveries of 97 % using sodium isopropyl xanthate (SIX) 0.06 g-L-1 and 0.04 g-L-1 of frother, at a Jg of 1.0 cm-s-1 and Jl of 0.72 cm-s-1. Xanthate-promoter combinations do not improve the separation; however, recoveries of 91.5% are achieved. The control of pH at 6.0 during the ion flotation of silver helps to improve the separation, compared to pH values of 7.0 and 8.0. The kinetic constant of apparent flotation k (min-1) maintains a linear behavior with the recovery and the dispersion properties, until reaching a slope change in the plot of Eg Vs Jg, where the system changes bubble flow regime, from homogeneous to turbulent.

Este estudio investiga y determina las propiedades de la dispersión (Jg, Eg y Db), los parámetros cinéticos y la hidrodinámica del sistema y su efecto en la recuperación de plata contenida en líquidos fijadores diluidos agotados, mediante la flotación iónica en columnas. Los resultados experimentales muestran recuperaciones de plata del 97 %, usando xantato isopropílico de sodio (XIS) en concentración de 60 mg L-1 y 40 mg L-1espumante, Jg de 1.0 cm·s-1, y Jl de 0.72 cm s -1. Combinaciones de xantato y promotor no mejoran la separación, sin embargo, se logran recuperaciones del 91.5%. El control del pH en 6.0durante la flotacióniónica de plata contribuyea mejorar la separación respecto a los pH de 7.0 y 8.0. La constante cinética de flotación aparente mantiene un comportamiento lineal con la recuperación y las propiedades de la dispersión, hasta el cambio de pendiente en el grafico de Eg Vs Jg, donde el sistema cambia de régimen de flujo de homogéneo a turbulento.