Resumen El grado de calidad de piezas fabricadas por inyección de termoplásticos se puede establecer por el peso del producto, apariencia y mínimos defectos. Adicionalmente, las condiciones del proceso de inyección pueden inducir un efecto en el desempeño mecánico de las piezas inyectadas, donde los esfuerzos residuales de la pieza inyectada generados en el procesamiento pueden promover la formación de grietas o fallas prematuras del producto durante su uso al aplicarle una carga o fuerza externa. El propósito del presente trabajo es evaluar el efecto que genera el procesamiento por inyección en una pieza inyectada en el desempeño mecánico de esta. Para tal fin, se inyectaron probetas bajo diferentes condiciones de proceso y posteriormente estas fueron sometidas a pruebas mecánicas de flexión, algunas piezas fueron llevadas a un tratamiento térmico de recocido “annealing”, con el fin de obtener una relajación molecular que permita reducir sus esfuerzos internos o residuales generados durante el proceso de inyección. Adicionalmente, se hizo una evaluación cualitativa de la distribución de esfuerzos residuales en las piezas inyectadas mediante la técnica de fotoelasticidad, para complementar y validar los resultados de las pruebas mecánicas. Se halló en los resultados de las muestras inyectadas a temperatura de molde de 50 ºC una mayor liberación de esfuerzos residuales de acuerdo con las imágenes de fotoelasticidad analizadas y un mayor porcentaje de incremento en la resistencia a la flexión de estas piezas al aplicar el tratamiento térmico. Lo que podría sugerir una mayor generación de esfuerzos residuales a esta temperatura de molde con respecto a la temperatura de molde recomendada de 80 ºC. El efecto de tratamiento térmico mejora significativamente el desempeño mecánico de todas las piezas evaluadas a las diferentes condiciones de proceso.

Abstract The quality of parts manufactured by thermoplastics injection molding can be evaluated based on product weight, appearance, and presence of defects. Furthermore, the conditions of the injection process can significantly influence the mechanical performance of the molded parts. Residual stresses generated during plastic processing may contribute to the formation of cracks or premature failures when the product is subjected to external loads or forces. This study aims to evaluate the effects of the injection process on an injected part and how they affect its mechanical performance. For this purpose, specimens were injected under different process conditions and, subsequently, employed in a. Some parts were also subjected to annealing (a thermal treatment) to induce molecular relaxation, which helps to reduce internal or residual stresses generated during the injection process. Additionally, a qualitative evaluation of the distribution of residual stresses in the injected parts was conducted using the s technique to complement and validate the results of the mechanical tests. The results of the specimens injected at a mold temperature of 50°C showed a greater release of residual stresses, as indicated in photoelasticity images analyzed here, and a noticeable increase in flexural strength if the heat treatment had been applied. This suggests that more residual stresses are produced at 50°C than at the recommended mold temperature of 80°C. The heat treatment significantly improved the mechanical performance of all the parts injected in this study under different processing conditions.

ABSTRACT Objective: To estimate the heritability (h2) of age at first parturition (AFP), longevity (L), useful life (UL), and productivity (P), as well as the genetic (rg) and phenotypic correlations between those traits in Brown Swiss and Holstein cows in Northwestern Honduras. Materials and methods: Cattle were raised under tropical conditions and intensive management. The model for AFP assessed the effect of contemporary group (herd, year and birth season combination) as fixed. The model used for L, UL and P included the contemporary group, age group at first calving and their interaction. Data were analyzed using restricted maximum likelihood procedure, adjusted to a univariate and to a bivariate animal model. Results: The h2 estimated for AFP, L, UL and P were 0.16, 0.18, 0.25 and 0.09, respectively, in Brown Swiss cows, and 0.53, 0.49, 0.7 and 0.22, respectively in Holstein. Negative but favorable rg among Brown Swiss cow traits ranged from 0.31 to 0.46 between AFP and the other traits. However, for Holsteins cows, positive rg among AFP and the other traits here studied varied from 0.49 to 0.96. In both cattle breeds, rg among L, UL and P, traits were positive. Conclusions: For all traits evaluated low to medium heritability's for BS suggest that a slow genetic improvement could be achieved if independent selection of traits is applied, and better response could be expected for H breed. For both breeds the positive rg among L, UL and P suggest thar similar selection criteria could be used.

RESUMEN Objetivo: Estimar heredabilidades (h2) de edad al primer parto (AFP), longevidad (L), vida útil (UL) y productividad (P), y las correlaciones fenotípicas y genéticas (rg) entre esos caracteres en vacas Suizo Pardo (SP) y Holstein en el Noroeste de Honduras. Materiales y métodos: El ganado fue criado en condiciones tropicales y manejado intensivamente. El modelo para AFP incluyó el grupo contemporáneo (GC, combinación de hato, año y época de nacimiento) como fijo. Para L, UL y P, el modelo incluyó al GC, grupo de edad al primer parto y su interacción. Los datos se analizaron utilizando el procedimiento de máxima verosimilitud restringida (REML), ajustado a un modelo animal univariado y bivariado. Resultados: Las h2 estimadas para AFP, L, UL y P fueron 0.16, 0.18, 0.25 y 0.09, en vacas SP; y 0.53, 0.49, 0.7 y 0.22 en H, respectivamente. Las rg fueron negativas pero favorables para las vacas SP en un rango de 0.31 a 0.46 entre AFP y los otros rasgos. Sin embargo, para las vacas H, se encontró una rg positiva entre AFP y las demás características que osciló entre 0.49 y 0.96. En ambas razas, las rg entre L, UL y P fueron positivas. Conclusiones: Para los rasgos evaluados, la h2 baja a media para BS sugiere que la mejora genética sería lenta si se aplicará selección independiente esperándose una mejor respuesta para la raza H. Para ambas razas las rg positivas sugieren que se podrían utilizar criterios de selección similares para L, UL y P.

Abstract Background: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, patients with chronic kidney disease vulnerable to suffering more severe COVID-19 disease and worse outcomes have been identified Objectives: Our study's aim was to determine the incidence, characteristics, and outcomes of SARS-CoV-2 infection in patients of hemodialysis (HD) units in Mexico and to describe the availability of confirmatory testing Methods: This study was multicentric study of 19 HD units, conducted between March 2020 and March 2021 Results: From a total of 5779 patients, 955 (16.5%) cases of suspicious COVID-19 were detected; a SARS-CoV-2 reverse transcription polymerase chain reaction test was done in only 50.6% of patients. Forty-five percentages were hospitalized and 6% required invasive mechanical ventilation (IMV). There was no significant difference in mortality between confirmed (131/483) and suspicious (124/472) cases (p = 0.74). The percentage of patients in need of hospitalization, IMV, and deceased was greater than in the rest of the study population Conclusions: The study revealed that 49.4% of the cases were not confirmed, a worrisome observation given that this is a highly vulnerable population (higher probability of contagion and worse outcomes), in which 100% of patients should have a confirmatory test

Abstract Lateral abdominal herniae are rare, they usually occur after trauma, vascular or renal surgery, their incidence is less than 2%. Since 1906 there are just about 250 reported cases and there are many treatment options, including laparoscopic approach, direct muscle approximation with sutures, mesh, suture anchors and, even, conservative treatment. We present the case of a 30 year old male who suffers a motorcycle crash that results in a posttraumatic flank hernia. He was treated with a delayed abdominal wall reconstruction using polypropylene mesh and a fascia lata graft. There is no algorithm or specific treatment for lateral abdominal herniae and, because of its low incidence, little is known about their evolution and long-term results of the distinct reconstruction techniques. It's possible to reconstruct the abdomen wall early or delay it, depending on the abdominal cavity contamination and the patient's general condition.

Resumen Objetivo: El objetivo del presente estudio fue determinar el efecto de la suplementación con extracto de Passiflora ligularis (granadilla), sobre algunos marcadores de inflamación crónica de bajo grado asociados al sobrepeso en un modelo de ratones albinos alimentados con dieta alta en grasa. Materiales y métodos: Se utilizaron 36 ratones albinos, distribuidos en un diseño irrestrictamente al azar, en 3 tratamientos y 12 repeticiones. Los tratamientos representaron un grupo con dieta control, un segundo tratamiento con dieta alta en grasa y un grupo que recibió alimento alto en grasa y suplementación con 3g/L de extracto de Passiflora ligularis en el agua de bebida. Pasados 49 días, se evaluaron las variables consumo de alimento, consumo de agua y ganancia de peso, además se evaluaron las concentraciones séricas de los marcadores de inflamación IL-6 y TNF-α. Resultados: La suplementación con extracto de Passiflora ligularis redujo (p < 0,05) la ganancia de peso de los ratones, en comparación con los animales que recibieron la dieta alta en grasa sin suplementación, los niveles séricos de TNF- α en los ratones suplementados no presentaron diferencias con ninguno de los dos grupos control, mientras que las cantidades de IL-6 no fueron afectados por los tratamientos. Conclusión: La concentración de 3g/L en el agua de bebida el extracto de Passiflora ligularis disminuyó la ganancia de peso producida por el aumento de la grasa en la dieta, y redujo la medición del marcador de inflamación sérico TNF-α, indicando un efecto benéfico sobre el riesgo asociado a la inflamación crónica de bajo grado.

Abstract Objective: The objective of this study was to determine the effect of the supplementation with Passiflora ligularis (granadilla) extract on some low-grade chronic inflammation markers associated with overweight in a model of albino mice fed a high-fat diet. Materials and methods: thirty-six albino mice were used, distributed in an unrestrictedly random design in 3 treatments and 12 repetitions. The treatments represented a group with a control diet, a second treatment with a high-fat diet, and a group that received high-fat food and supplementation with 3g/L of Passiflora ligularis extract in the drinking water. After 49 days, the variables food consumption, water consumption, and weight gain were evaluated, in addition to the serum concentration of the inflammation markers IL-6 and TNF-α. Results: Supplementation with Passiflora ligularis extract reduced (p < 0.05) the weight gain of mice compared to animals that received the high-fat diet without supplementation. Serum levels of TNF-α on supplemented mice did not show differences with neither of both control groups while the amounts of IL-6 were not affected by the treatments. Conclusion: The concentration of 3g/L in the drinking water of the of Passiflora ligularis extract decreased the weight gain produced by the increase fat in diet and reduced the measurement of the serum inflammation marker TNF-α indicating a beneficial effect on the risk associated with chronic low-grade inflammation.

Abstract Objective: to describe the clinical presentation, diagnosis, and surgical treatment of a patient with superior mesenteric artery syndrome or Wilkie syndrome combined with the nutcracker syndrome or left renal vein compression syndrome in a tertiary referral center in a Latin American country. Case description: a 25-year-old male patient from the United States who attended for a year of weight loss and intestinal obstruction episodes of unknown etiology after multiple imaging studies. Endoscopic studies were performed without findings. While in the recovery room, he developed abdominal pain requiring admission to the emergency service. The CT enterography showed dilation of the colon loops and small intestine with a decrease of the aortomesenteric (AOM) angle and the gastrointestinal series with the filiform passage of the contrast medium. Conservative management was attempted as initial therapy with intolerance to enteric nutritional support. Finally, we initially opted for surgical treatment, with a slow recovery process, but in the end, with a resolution of symptoms and weight gain. Conclusion: Wilkie syndrome is a rare disease and a diagnostic challenge in patients with weight loss and abdominal pain. We described a superior mesenteric artery compression case in which diagnosis was achieved with multiple diagnostic strategies and complete resolution after surgical treatment. The decreased aortomesenteric angle may compress the superior mesenteric artery and the left renal vein. In this case, it resulted in a combined Wilkie and nutcracker syndrome.

Resumen Objetivo: describir la presentación clínica, el diagnóstico y el tratamiento quirúrgico de un paciente con síndrome de la arteria mesentérica superior o síndrome de Wilkie combinado con síndrome de cascanueces o síndrome de compresión de la vena renal izquierda, en un centro de alta complejidad de un país latinoamericano. Descripción del caso: paciente masculino de 25 años, procedente de Estados Unidos, quien consultó por un año de pérdida de peso y episodios de obstrucción intestinal de etiología desconocida tras múltiples estudios de imagen. Se le realizaron estudios endoscópicos sin hallazgos; en la sala de recuperación desarrolló dolor abdominal que requirió ingreso al servicio de urgencias. La enterotomografía mostró dilatación de asas de colon e intestino delgado, con disminución del ángulo aortomesentérico y la serie gastrointestinal con paso filiforme del medio de contraste. Se intentó el manejo conservador como terapia inicial, con intolerancia al soporte nutricional entérico. Finalmente, se optó por el tratamiento quirúrgico, con un proceso de recuperación tórpido inicialmente, pero al final con resolución de los síntomas y aumento de peso. Conclusión: el síndrome de Wilkie es una enfermedad rara y un desafío diagnóstico en pacientes con pérdida de peso y dolor abdominal. Describimos un caso de compresión de la arteria mesentérica superior en el que se logró el diagnóstico con múltiples estrategias diagnósticas y resolución completa luego del tratamiento quirúrgico. La disminución del ángulo aortomesentérico puede comprimir la arteria mesentérica superior, así como la vena renal izquierda, que en ese caso resultó en un síndrome combinado de Wilkie y de cascanueces.

Abstract Chronic kidney disease (CKD) in the diabetic patient is mainly a consequence of long-term diabetes mellitus itself. In Mexico approximately 50% of patients on dialysis are diabetics and this will could increase in the coming years. New therapeutic options available, combined with lifestyle changes, have improved glycemic control and may contribute to delay the onset as well as the progression of CKD. International scientific societies have developed clinical guidelines for the diagnosis and management of CKD in diabetics, although in some points, these recommendations are not adapted to the Mexican reality. We hereby present the conclusions of the consensus reached by Mexican specialists on diabetic nephropathy.

Resumen La enfermedad renal crónica (ERC) del paciente diabético es frecuentemente una consecuencia directa de la diabetes mellitus (DM) de larga evolución y se la conoce como nefropatía diabética. En México cerca del 50% de los pacientes en terapia sustitutiva de la función renal tienen ERC por DM, y este porcentaje podría aumentar en los próximos años. Nuevas opciones terapéuticas, combinadas con cambios en el estilo de vida, han mejorado el control de la glucemia y pueden contribuir sustancialmente a retrasar la aparición o la progresión a estadios avanzados de la ERC. Las sociedades científicas internacionales han elaborado guías clínicas para el diagnóstico y manejo de la nefropatía diabética, sin embargo, en algunos puntos estas recomendaciones no se adaptan a la realidad mexicana. Se presentan las conclusiones de un consenso realizado por especialistas mexicanos sobre diabetes y ERC, con especial énfasis en el uso de los inhibidores del cotransportador de sodio-glucosa.

Abstract Bat ectoparasites have a complex natural history narrowly tied to their hosts at ecological, behavioral, and evolutionary scales. As flying and social organisms, bats represent a potential mechanism of dispersal, a source of feeding, and a roost for ectoparasite reproduction. The chiggerflea Hectopsylla pulex (Siphonaptera: Tungidae) is widely distributed across the Neotropics. Females of this ectoparasite have been found in their neosomal form on bats of the family Molossidae, Noctilionidae, Phyllostomidae, and Vespertilionidae. Here we present the record of infestation of chiggerfleas on the Argentine bat, Eptesicus furinalis (Vespertilionidae) in Colombia, representing the first record of the flea on this species, and providing novel genetic information of this poorly known flea species.

RESUMO Identificar e classificar as informações disponíveis sobre o COVID-19 e o tratamento oftalmológico de acordo com o nível de evidência, dentro de quatro tópicos principais de interesse: evidência do vírus nas lágrimas e na superfície ocular, infecção pela via conjuntival, manifestações oculares e recomendações de melhores práticas. Foi realizada uma revisão estruturada no PubMed, ScienceDirect, LILACS, SciELO, Biblioteca Cochrane e Google Scholar no COVID-19 e oftalmologia. A planilha de Níveis de Evidência 2011 do Oxford Centre for Evidence Based Medicine 2011 foi usada para avaliações de qualidade. Mil e dezoito itens foram identificados na busca; Foram incluídos 26 registros na síntese qualitativa, que incluiu 6 revisões de literatura, 10 séries de casos ou estudos transversais, 4 relatos de casos e 6 descrições de intervenções. Dezessete dos 26 registros (65%) foram classificados como nível 5 no sistema de classificação da metodologia Oxford CBME, o restante foi no nível 4. As evidências geradas no COVID-19 e na oftalmologia até o momento são limitadas, embora isso seja compreensível dadas as circunstâncias. Tanto a possível presença de partículas virais em lágrimas e conjuntiva quanto o potencial de transmissão conjuntival permanecem controversos. As manifestações oculares não são frequentes e podem se assemelhar a infecção viral da superfície ocular. A maioria das recomendações baseia-se nas estratégias implementadas pelos países asiáticos durante surtos anteriores de coronavírus. Há necessidade de estudos aprofundados avaliando essas estratégias no cenário da SARS-CoV-2. Enquanto isso, os planos para a aplicação dessas medidas devem ser implementados com cautela, levando em consideração o contexto de cada país e submetidos a auditorias periódicas.

ABSTRACT To identify and classify available information regarding COVID-19 and eye care according to the level of evidence, within four main topics of interest: evidence of the virus in tears and the ocular surface, infection via the conjunctival route, ocular manifestations, and best practice recommendations. A structured review was conducted in PubMed, ScienceDirect, LILACS, SciELO, the Cochrane Library and Google Scholar on COVID-19 and ophthalmology. The Oxford Centre for Evidence Based Medicine 2011 Levels of Evidence worksheet was used for quality assessments. 1018 items were identified in the search; 26 records were included in the qualitative synthesis, which encompassed 6 literature reviews, 10 case series or cross-sectional studies, 4 case reports, and 6 intervention descriptions. Seventeen out of 26 records (65%) were categorized as level 5 within the Oxford CBME methodology grading system, the rest were level 4. The evidence generated on COVID-19 and ophthalmology to date is limited, although this is understandable given the circumstances. Both the possible presence of viral particles in tears and conjunctiva, and the potential for conjunctival transmission remain controversial. Ocular manifestations are not frequent and could resemble viral infection of the ocular surface. Most recommendations are based on the strategies implemented by Asian countries during previous coronavirus outbreaks. There is a need for substantive studies evaluating these strategies in the setting of SARS-CoV-2. In the meantime, plans for applying these measures must be implemented with caution, taking into account the context of each individual country, and undergo regular evaluation.

To identify and classify available information regarding COVID-19 and eye care according to the level of evidence, within four main topics of interest: evidence of the virus in tears and the ocular surface, infection via the conjunctival route, ocular manifestations, and best practice recommendations. A structured review was conducted in PubMed, ScienceDirect, LILACS, SciELO, the Cochrane Library and Google Scholar on COVID-19 and ophthalmology. The Oxford Centre for Evidence Based Medicine 2011 Levels of Evidence worksheet was used for quality assessments. 1018 items were identified in the search; 26 records were included in the qualitative synthesis, which encompassed 6 literature reviews, 10 case series or cross-sectional studies, 4 case reports, and 6 intervention descriptions. Seventeen out of 26 records (65%) were categorized as level 5 within the Oxford CBME methodology grading system, the rest were level 4. The evidence generated on COVID-19 and ophthalmology to date is limited, although this is understandable given the circumstances. Both the possible presence of viral particles in tears and conjunctiva, and the potential for conjunctival transmission remain controversial. Ocular manifestations are not frequent and could resemble viral infection of the ocular surface. Most recommendations are based on the strategies implemented by Asian countries during previous coronavirus outbreaks. There is a need for substantive studies evaluating these strategies in the setting of SARS-CoV-2. In the meantime, plans for applying these measures must be implemented with caution, taking into account the context of each individual country, and undergo regular evaluation.

Identificar e classificar as informações disponíveis sobre o COVID-19 e o tratamento oftalmológico de acordo com o nível de evidência, dentro de quatro tópicos principais de interesse: evidência do vírus nas lágrimas e na superfície ocular, infecção pela via conjuntival, manifestações oculares e recomendações de melhores práticas. Foi realizada uma revisão estruturada no PubMed, ScienceDirect, LILACS, SciELO, Biblioteca Cochrane e Google Scholar no COVID-19 e oftalmologia. A planilha de Níveis de Evidência 2011 do Oxford Centre for Evidence Based Medicine 2011 foi usada para avaliações de qualidade. Mil e dezoito itens foram identificados na busca; Foram incluídos 26 registros na síntese qualitativa, que incluiu 6 revisões de literatura, 10 séries de casos ou estudos transversais, 4 relatos de casos e 6 descrições de intervenções. Dezessete dos 26 registros (65%) foram classificados como nível 5 no sistema de classificação da metodologia Oxford CBME, o restante foi no nível 4. As evidências geradas no COVID-19 e na oftalmologia até o momento são limitadas, embora isso seja compreensível dadas as circunstâncias. Tanto a possível presença de partículas virais em lágrimas e conjuntiva quanto o potencial de transmissão conjuntival permanecem controversos. As manifestações oculares não são frequentes e podem se assemelhar a infecção viral da superfície ocular. A maioria das recomendações baseia-se nas estratégias implementadas pelos países asiáticos durante surtos anteriores de coronavírus. Há necessidade de estudos aprofundados avaliando essas estratégias no cenário da SARS-CoV-2. Enquanto isso, os planos para a aplicação dessas medidas devem ser implementados com cautela, levando em consideração o contexto de cada país e submetidos a auditorias periódicas.

Resumen Introducción. Staphylococcus aureus resistente a la meticilina (SARM) es un microorganismo que coloniza las fosas nasales y diferentes partes del cuerpo, lo cual se considera un factor de riesgo para adquirir infecciones invasivas, especialmente en pacientes sometidos a cirugía cardiovascular. Objetivo. Determinar la colonización nasal por SARM y establecer las características clínicas en pacientes programados para cirugía cardiovascular. Materiales y métodos. Se hizo un estudio descriptivo entre febrero y diciembre de 2015. Se incluyeron pacientes adultos programados para cirugía cardiovascular en el Hospital Universitario San Ignacio de Bogotá. La colonización se identificó mediante reacción en cadena de la polimerasa (Polymerase Chain Reaction, PCR) en tiempo real en muestras obtenidas mediante hisopados nasales. Los pacientes fueron descolonizados con mupirocina al 2,0 % intranasal dos veces al día y baños con gluconato de clorhexidina al 4 % del cuello hacía abajo durante cinco días, al cabo de lo cual se hizo una PCR de control. Resultados. Se incluyeron 141 pacientes, 52 hospitalizados y 89 ambulatorios. Del total, 19 (13,4 %) tenían colonización nasal por SARM, correspondientes a 9 (17,3 %) de los 52 hospitalizados y 10 (11,2 %) de los 89 ambulatorios. Todos los pacientes sometidos a descolonización tuvieron resultado negativo en la PCR al final del proceso y ninguno presentó infección del sitio operatorio por S. aureus. Conclusiones. Se demostró colonización nasal por SARM tanto en los pacientes hospitalizados como en los ambulatorios. La descolonización con mupirocina fue efectiva para erradicar el estado de portador a corto plazo, lo que podría tener efecto en las tasas de infección del sitio operatorio en las cirugías cardiovasculares.

Abstract Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is a microorganism that colonizes nostrils and different parts of the body, which is considered a risk factor to acquire invasive infections, especially in cardiovascular surgery patients. Objective: To determine the frequency of nasal colonization by MRSA and to establish the clinical characteristics in patients scheduled for cardiovascular surgery. Materials and methods: This was a descriptive study conducted between February and December, 2015. We included adult patients scheduled for cardiovascular surgery at the Hospital Universitario San Ignacio in Bogotá, Colombia. Colonization was identified by real-time PCR from nasal swabs. Colonized patients were treated with mupirocin 2.0% intranasally twice a day and bathed with chlorhexidine 4% from the neck downwards for five days. At the end of this treatment, PCR control was carried out. Results: We included 141 patients with a percentage of nasal colonization of 13.4% (19/141). There were 52 hospitalized patients and 89 outpatients with a percentage of nasal colonization of 17.3% (9/52), and 11.2% (10/89), respectively. All colonized patients who received treatment had a negative PCR at the end of the regime and none of the participating patients had a surgical site infection by S. aureus at the end of the study. Conclusions: Nasal colonization was observed both in hospitalized patients and outpatients. Decolonization treatment with mupirocin was effective to eradicate the carrier state in the short term, which could impact the rates of surgical wound infection associated with cardiovascular surgery.

Resumen La enfermedad de Alzheimer es un desorden neurodegenerativo-progresivo que afecta la producción de lenguaje y las capacidades de pensamiento de los pacientes. La integridad del cerebro es destruida con el paso del tiempo por interrupciones en las interacciones entre neuronas y células, requeridas para su funcionamiento normal. La enfermedad incluye el deterioro de habilidades comunicativas por un habla deficiente, que usualmente contiene información inservible, baja densidad de ideas y habilidades gramaticales. Adicionalmente, los pacientes presentan dificultades para encontrar palabras apropiadas y así estructurar oraciones. Por lo anterior, hay investigaciones en curso que buscan detectar la enfermedad considerando el deterioro de la producción de lenguaje. Así mismo, se están usando técnicas de procesamiento de lenguaje natural para detectar patrones y reconocer las discapacidades del lenguaje de los pacientes. Por su parte, este artículo se enfoca en el uso de características basadas en embebimiento y frecuencia de palabras, además de hacer una nueva aproximación con características gramaticales para clasificar la enfermedad de Alzheimer. Para ello, se consideraron transcripciones de 98 pacientes con Alzheimer y 98 controles sanos del Pitt Corpus incluido en la base de datos Dementia-Bank. Un total de 1200 características de embebimientos de palabras, 1408 características de frecuencia de término inverso vs. frecuencia en documentos, y 8 características gramaticales fueron calculadas. Tres modelos fueron propuestos, basados en la extracción de dichos conjuntos de características por separado y un cuarto modelo fue basado en una estrategia de fusión temprana de los tres conjuntos de características. Los modelos fueron optimizados usando la estrategia de validación cruzada Leave-One-Out. Se alcanzaron tasas de aciertos de hasta 81.7 % usando la fusión temprana de todas las características. Además, se encontró que un pequeño conjunto de características gramaticales logró una tasa de acierto del 72.8 %. Así, los resultados indican que estas características son adecuadas para clasificar de manera efectiva entre pacientes de Alzheimer y controles sanos.

Abstract Alzheimer's Disease (AD) is a progressive neurodegenerative disorder that affects the language production and thinking capabilities of patients. The integrity of the brain is destroyed over time by interruptions in the interactions between neuron cells and associated cells required for normal brain functioning. AD comprises deterioration of the communicative skills, which is reflected in deficient speech that usually contains no coherent information, low density of ideas, and poor grammar. Additionally, patients exhibit difficulties to find appropriate words to structure sentences. Multiple ongoing studies aim to detect the disease considering the deterioration of language production in AD patients. Natural Language Processing techniques are employed to detect patterns that can be used to recognize the language impairments of patients. This paper covers advances in pattern recognition with the use of word-embedding and word-frequency features and a new approach with grammar features. We processed transcripts of 98 AD patients and 98 healthy controls in the Pitt Corpus of the Dementia-Bank database. A total of 1200 word-embedding features, 1408 Term Frequency-Inverse Document Frequency features, and 8 grammar features were extracted from the selected transcripts. Three models are proposed based on the separate extraction of such feature sets, and a fourth model is based on an early fusion strategy of the proposed feature sets. All the models were optimized following a Leave-One-Out cross validation strategy. Accuracies of up to 81.7 % were achieved using the early fusion of the three feature sets. Furthermore, we found that, with a small set of grammar features, accuracy values of up to 72.8 % were obtained. The results show that such features are suitable to effectively classify AD patients and healthy controls.

Resumen La educación virtual se ha convertido en una de las herramientas más utilizadas por los estudiantes en todos los niveles educativos, no solo por la comodidad y la flexibilidad, sino también por la posibilidad de ampliar la cobertura educativa en una población. Todos estos beneficios traen consigo múltiples problemas de seguridad y confiabilidad a la hora de evaluar el proceso de aprendizaje del estudiante, ya que las estrategias tradicionales de verificación de identidad, como la combinación de nombre de usuario y contraseña, no garantizan que el estudiante matriculado en el curso realmente realice el examen. Por lo tanto, es necesario diseñar un sistema con otro tipo de estrategia de verificación para diferenciar un usuario válido de un impostor. Este estudio propone un nuevo método de verificación, basado en el cálculo de distancias entre los modelos de mezclas gaussianas creados con diferentes tareas de escritura. El enfoque propuesto es evaluado en dos modalidades diferentes llamadas verificación intrusiva y verificación no intrusiva. El modo intrusivo proporciona una tasa de falsos positivos de 16 %, mientras el modo no intrusivo provee una tasa de falsos positivos de 12 %. Además, la estrategia propuesta para verificación no intrusiva es comparada con un trabajo previamente reportado en la literatura y los resultados muestran que nuestro enfoque reduce la tasa de error en aproximadamente un 24.3 %. La estrategia implementada no necesita hardware adicional, solo es requerido el teclado del computador para realizar la verificación, lo que hace que el sistema sea atractivo y flexible para ser usado en plataformas de educación virtual.

Abstract Virtual education has become one of the tools most widely used by students at all educational levels, not just because of its convenience and flexibility, but also because it can expand educational coverage. All these benefits also bring along multiple issues in terms of security and reliability in the evaluation the of student’s knowledge because traditional identity verification strategies, such as the combination of username and password, do not guarantee that the student enrolled in the course really takes the exam. Therefore, a system with a different type of verification strategy should be designed to differentiate valid users from impostors. This study proposes a new verification system based on distances computed among Gaussian Mixture Models created with different writing task. The proposed approach is evaluated in two different modalities namely intrusive verification and non-intrusive verification. The intrusive mode provides a false positive rate of around 16 %, while the non-intrusive mode provides a false positive rate of 12 % In addition, the proposed strategy for non-intrusive verification is compared to a work previously reported in the literature and the results show that our approach reduces the equal error rate in about 24.3 %. The implemented strategy does not need additional hardware; only the computer keyboard is required to complete the user verification, which makes the system attractive, flexible, and practical for virtual education platforms.

ABSTRACT In Chile, the manipulation for scientific purposes of terrestrial vertebrates from natural populations is conducted previous authorization of the Agricultural and Livestock Service and various Bioethics Committees. Obtaining such authorizations is becoming increasingly complex. The procedures do not fit the reality of scientific work, and they seem to be based on unjustified assessments of the effects of animal handling on natural populations. The aim of this commentary is to initiate a discussion in order to establish a norm of scientific manipulation of terrestrial vertebrates adjusted to biological reality and that does not interfere with scientific research.

RESUMEN La manipulación con fines científicos de vertebrados terrestres en poblaciones naturales chilenas se debe realizar previa autorización del SAG y de Comités de Bioética institucionales. Obtener dichas autorizaciones es cada vez más complejo; los trámites no se adecúan al quehacer científico ni al conocimiento sobre el efecto de la manipulación en las poblaciones naturales. El objetivo de este comentario es contribuir a una discusión en pos del establecimiento de una normativa de manipulación científica de vertebrados terrestres ajustada a la realidad biológica y que no entorpezca la investigación científica.

Abstract Approximately 65% of children with newly diagnosed epilepsy achieve sustained control of their epileptic seizures with the antiepileptic drug (AED) initially prescribed, and 15-20% require the combination of other AEDs. To begin treatment with an AED, basic aspects should be considered, such as the capacity for absorption, distribution, metabolism, and elimination of the drug. Treatment with an AED in pediatric patients, as for any age, must be personalized, but in these cases, the biological age and its degree of development are fundamental. Furthermore, the type of seizure, type of epileptic syndrome, comorbidity, in many cases the etiology, and even other aspects such as tolerability and availability of use must be considered. If adequate seizure control is not achieved, synergistic combinations could be used, making sure that adverse effects are not increased. Remember that a high percentage of patients initiate their epilepsy in the pediatric stage, which is why management in this age group is fundamental, and doses must always be calculated in relation to the weight of the patient.

Resumen Alrededor del 65% de los niños con epilepsia de reciente diagnóstico logran el control sostenido de sus crisis epilépticas (CE) con el fármaco antiepiléptico (FAE) inicialmente prescrito y un 15-20% requieren la combinación de otros FAE. Para el inicio del tratamiento con un FAE deben considerarse aspectos básicos como son la capacidad de absorción, distribución, metabolismo y eliminación del fármaco. El inicio de tratamiento con FAE en edad pediátrica, como en cualquier edad, tiene que ser personalizado, pero en estos casos la edad biológica y su grado de desarrollo es fundamental; así mismo, debe de tomarse en cuenta el tipo de crisis, tipo de síndrome epiléptico, la comorbilidad, en muchos casos la etiología, e incluso otros aspectos como son la tolerabilidad y la disponibilidad de uso. En caso de no lograrse un control adecuado de crisis, se deberán realizar combinaciones sinérgicas, vigilando que no se incrementen los efectos adversos. Recordemos que un alto porcentaje de pacientes inician su epilepsia en la etapa pediátrica, razón por la cual el tratamiento en este grupo de edad es fundamental y donde manejamos siempre dosis calculadas en relación al peso del paciente.