Resumen Se presenta una implementación básica del método de hidrodinámica de partículas suavizadas con compresibilidad artificial (W-SPH) para modelar fenómenos de flujo de superficie libre, y se muestra su aplicación a tres casos de interés general. Estos casos de estudio son aproximaciones bidimensionales de dos tipos de problema hidráulico conocidos: Rotura de presa sobre lecho seco y rotura de presa sobre lecho húmedo, esta última con dos variantes de profundidad de lecho. Para todos los modelos, los resultados se compararon con los datos de los perfiles de frente de avance de experimentos para los que hay datos publicados. El modelo numérico convergió a una solución estable con configuraciones de resolución relativamente bajas (2000 a 20000 partículas) y se encontró una buena correlación con las referencias experimentales y numéricas, incluso sin la aplicación de algoritmos de corrección. Las oscilaciones numéricas en el campo de densidad produjeron pequeñas crestas y vórtices artificiales, pero no interfirieron demasiado con el comportamiento macroscópico del fluido, excepto por cierto retraso en la velocidad de las ondas superficiales. La elección de desarrollar un código fuente autónomo completamente original, aunque muy revelador, implica que el algoritmo de búsqueda de partículas vecinas utilizado incrementa considerablemente el costo computacional asociado. Según los cotejos con datos experimentales, se establecieron prioridades de optimización para el código fuente y se esbozaron algunas pautas para elegir la resolución del fluido y la densidad de frontera para casos futuros, donde los fenómenos de flujo sean similares a los estudiados. Además, la experiencia de escribir el código fuente SPH que se utilizó para resolver los modelos numéricos, muestra el camino para desarrollos futuros en el modelado de flujo de fluidos usando este método.

Abstract A basic implementation of the weakly compressible smoothed particle hydrodynamics (W-SPH) method is used to model the open surface flow phenomena of three different cases of hydraulic problems. They were all two-dimensional approximations of known hydraulics problems: dam break over dry bed and dam break over wet bed with shallow and deep variants. For all models, the results were compared quantitatively with data from waterfront profiles from previously published experiments. A qualitative approach was used to assess the general profile shape comparing the numerical hydraulic profile results with published photographs of all setups shown. The numerical model converged to a stable solution with relatively low-resolution setups (2000 to 20000 particles) and a good correlation was found with the experimental and numerical references, even without the application of correction algorithms. Numerical oscillations in the density field did produce small artificial waves and vortices, but did not interfere with the behavior of the bulk of the fluid except for some delay in the speed of surface waves. The choice of developing an entirely original, self-contained source code, although very insightful, does mean that the neighboring particle search algorithm implemented considerably increases the associated computational cost. However, using this insight along with the basis of the comparison with experimental results, optimization priorities for the source code were found and some guidelines to choose fluid resolution and boundary density can be applied for future cases where the flow phenomena are similar to those studied. Also, the experience of writing the SPH source code that was used to solve the numerical models, shows the path for future developments on fluid flow modeling using this method.

Abstract: Objective: To describe the behavior of SARS-CoV-2 epidemic among workers affiliated to the Mexican Social Security Institute. Materials and methods: We analyzed Short Term Disability Claims due to Respiratory Diseases (RD-STDC), associated hospitalizations and deaths (March 1 - December 31, 2020). We estimated the attack rate (AR) for SARS-CoV-2, and relative risks (RR) of TWD-RD, hospitalization and deaths. Results: 1 730 334 workers received at least one RD-STDC. AR was higher in women and in both sexes it was lower in >60 years old. RR of hospitalization and death were higher in men and increased with age. Compared with RD-STDC of 2015-2019, the states of Durango, Tamaulipas and Nuevo Leon had a higher RR of RD-STDC than the rest of the country. Conclusions: The SARS-CoV-2 epidemic impacted IMSS-affiliated workers significantly. We observed a 4.6 fold excess in RD-STDC compared to the expected frequency and nearly 1 million SARS-CoV-2 cases in this population. Our data suggest that the RD-STDC system can be used as an additional resource for epidemiological surveillance of emerging diseases.

Resumen: Objetivo: Describir el comportamiento de la epidemia de SARS-CoV-2 entre los trabajadores afiliados al Instituto Mexicano del Seguro Social (IMSS). Material y métodos: Se analizaron las incapacidades temporales para el trabajo por enfermedades respiratorias (ITT-ER), las hospitalizaciones y defunciones asociadas durante el periodo del 1 marzo al 31 diciembre 2020. Se estimó la tasa de ataque (TA) por SARS-CoV-2, así como los riesgos relativos (RR) de ITT-ER, hospitalización y defunción. Resultados: De los trabajadores afiliados al IMSS, 8.8% (n=1 730 334) recibió al menos una ITT-ER. La TA fue mayor en mujeres y en ambos sexos fue menor en el grupo de >60 años. Los RR de hospitalización y defunción fueron mayores en hombres y aumentaron con la edad. Comparado con las ITT-ER de 2015-2019, Durango, Tamaulipas y Nuevo León tuvieron un RR mayor de ITT-ER que el resto del país. Conclusiones: La epidemia de SARS-CoV-2 tuvo repercusiones importantes en los trabajadores afiliados al IMSS; se observó un exceso de ITT-ER de 4.6 veces respecto a la frecuencia esperada y cerca de un millón de casos de SARS-CoV-2. Los datos sugieren que el sistema de ITT-ER puede ser utilizado como elemento adicional para la vigilancia epidemiológica de enfermedades emergentes.

Background. Childhood spinal muscular atrophy is an autosomal recessive neuromuscular disease characterized by degeneration of the anterior horn cells of the spinal cord. SMA type I, the most severe form (Werdnig-Hoffmann disease) can be detected in utero or during the first months of life. Death typically occurs within the first 2 years of life. Case report. A 6-month-old female was admitted to the emergency room for severe respiratory distress. She had muscular hypotonia, intercostal muscle weakness and tongue fasciculations. Electromyography was compatible with motor polyneuropathy with axonal and myelin damage. Molecular analysis of SMN-1 gene reported homozygous for deletion of exons 7 and 8 of SMN-1 gene. Conclusions. It is imperative to recognize and diagnose this entity in order to provide genetic counseling to the family as well as to offer support and advice in the care of the patient.

Introducción. Las atrofias musculares espinales de la infancia son enfermedades neuromusculares hereditarias, autosómicas, recesivas, caracterizadas por la degeneración de las neuronas motoras del asta anterior de la médula espinal. La atrofia muscular espinal tipo I (enfermedad de Werdnig-Hoffmann) es la forma más severa. Se inicia in útero o durante los primeros meses de vida. La muerte suele ocurrir antes de los dos años de edad. Caso clínico. Lactante de 6 meses de edad que ingresa al Servicio de Urgencias por dificultad respiratoria severa. Presenta marcada hipotonía muscular, debilidad de musculatura intercostal y fasciculaciones de la lengua. La electromiografía es compatible con polineuropatía motora con daño mielínico y axonal. El análisis molecular reportó un estado homocigoto para la deleción de los exones 7 y 8 del gen SMN-1 . Con estos dos estudios se integra el diagnóstico de atrofia muscular espinal tipo 1 (enfermedad de Werdnig-Hoffmann). Conclusiones. Es importante conocer y diagnosticar esta entidad para brindar consejo genético a la familia, así como asesoramiento y apoyo en el manejo del paciente.

The objective of the present work was to analyze the transeriptional expression induced under different types of biotic and abiotic stress in Havana chili pepper (Capsicum chinense BG-3821). The studies of expression of plant genes under different conditions of biotic and abiotic stress are important because they are a strategy for understanding at molecular level, how plants act in phenomena of resistance to pathogen and abiotic growth conditions, which may expand the knowledge about molecular defense mechanisms to this type of stress in plants. For transeriptional analysis, molecular probes of R50 and R100 EST's were employed. Both are differential fragments and possibly implied in the resistance response of C.chineme BG-3S21 to infections by the pepper Huasteco yellow vein virus (PHYVV). Specificity of gene expressions corresponding to R50 and RKH) was confirmed in C. chinense plants infected by PHYVV, as well as by the Xantkomonas campestris pv, vesicatoria bacterium, and Fusarium solani fungus. Plants infected with the Phytophthora capsici nomycete did not induce the expression of these genes. Likewise, it was assessed if the expression of these genes is induced to C. chinense BG-3821 plants by application of salicylic acid (AS), jazmonate methyl, ethylene, or abiotic stress (hydric and thermal). Additionally, analysis of complementary DNA hybridization (cDNA) was conducted, for which various clones from subtractive hanks were selected, containing C. chinense BG-3821 fragments, whose expression was induced in infections of PHYVV. It was demonstrated that the gene expressions corresponding to R50 and R100 fragments are not only induced specifically by PHYVV infection, but also by X. campestris pv. vesicatoria, and F.solani, as well as by application of salicylic acid, jasmonate methyl, and ethyleue. In the analysis of arrangements, differences in the expression level of several EST's were observed for each evaluated stress condition.

El objetivo del presente trabajo fue analizar la expresión transcripcional inducida bajo diferentes tipos de estrés biótico y abiótico en plantas de chile habanero (Capsicum chinense BG-3821). Los estudios de expresión de genes de plantas bajo diferentes condiciones de estrés biótico y abiótico son importantes porgue son una estrategia para entender, a nivel molecular, cómo las plantas actúan en fenómenos de resistencia a patógenos y condiciones abióticas de crecimiento, lo que puede ampliar el conocimiento sobre los mecanismos moleculares de defensa a estos tipos de estrés en las plantas. Para el análisis transeripcional se emplearon sondas moleculares de los EST R50 y R100. Ambos son fragmentos diferenciales y posiblemente implicados en la respuesta de resistencia de C. chinense BG-3821 a infecciones por el virus huasteco vena amarilla del chile (PHYVV). Se comprobó la especificidad de la expresión de los genes correspondientes a R50 y R100 en plantas de C. chinense infectadas con PHYVV, así como por la bacteria Xanthomonas campestris pv. vesicatoria y el hongo Fusarium solani. Plantas infectadas con el oomiceto Phytophthora capsici no indujeron la expresión de estos genes. Asimismo, se evaluó si la expresión de estos genes es inducida mediante la aplicación de ácido salicílico (AS), metil Jasmonato, etileno o estrés abiótico (hídrieo y térmico) a plantas de C. chinense BG-3821, Adicionalmente, se realizó análisis de hibridación de ADN complementario (ADNc), para lo cual se seleccionaron varias clonas de bancos sustraetivos que contienen fragmentos de genes de C. chinense BG-3821 cuya expresión fue inducida en infecciones de PHYVV. Se demostró que la expresión de los genes correspondientes a los fragmentos R50 y R100 no son sólo inducidos específicamente por la infección de PHYVV, sino además por X. campestris pv. vesicatoria y F. solani, así como por la aplicación de ácido salicílico, metil jasmonato y etileno. En el análisis de arreglos se observaron diferencias en el nivel de expresión de varios EST para cada condición de estrés evaluada.

Cryptosporidium é um patógeno emergente que causa diarréia em humanos. Muitos surtos graves de criptosporodíase tem a água como possível origem da contaminação. Neste estudo foi investigada a presença do oocisto de Cryptosporidium sp. em águas de poço, usadas para consumo humano em Itaquaquecetuba - São Paulo. Os resultados evidenciaram a presença de oocistos em 2 fossas e em 8 poços analisados, mostrando o risco que esta água representa para consumo humano e a necessidade de práticas mais eficientes de desinfecção e monitoramento da presença deste parasita em amostras de águas no estado de São Paulo.

Cryptosporidium is an emergent pathogen that causes profuse diarrhea in humans. Outbreaks of human cryptosporidiosis have implicated water as a possible source of contamination. In this study the presence of Cryptosporidium sp. oocysts was investigated as well as the fecal contamination in groundwater for consumption in Itaquaquecetuba - São Paulo. Therefore, it was possible to notice that the septic tanks were located close to the wells, exposing them to risk of contamination. As a consequence of these results and observations efficient disinfecting practices and groundwater monitoring are recommended.

Foram analisadas amostras de águas subterrâneas de três cemitérios localizados em áreas geologicamente distintas de São Paulo e de Santos, Brasil, com relação às condições higiênicas e sanitárias. Para as primeiras foram considerados os coliformes totais, bactérias heterotróficas, microrganismos proteolíticos e lipolíticos. Para as sanitárias foram pesquisados coliformes fecais, estreptococos fecais, clostrídios sulfito redutores, colifagos e salmonelas. Verificou-se que as águas não apresentaram condições higiênicas satisfatórias e, em alguns casos, foram encontrados niveis altos de nitrato (75,7 mg/l). A deteção de níveis mais elevados de estreptococos fecais e de clostrídios sulfito redutores em relação aos coliformes fecais, na maior parte das amostras, parece mostrar que os dois primeiros indicadores seriam mais adequados para avaliação das condições sanitárias deste tipo de água. Foi detectada Salmonella apenas em uma amostra e não foram detectados colifagos. Na análise estatística, foram encontradas correlações significantes entre três indicadores de poluição fecal assim como entre as contagens em placas de bactérias heterotróficas aeróbias, anaeróbias e lipolíticas. Foi observada uma relação direta entre a deterioração da qualidade da água e as condições geológicas e hidrogeológicas do ambiente estudado, devendo este fator ser considerado para o planejamento e implantação de cemitérios.

Groundwater samples collected by piezometers from three cemiteries in geologically distinct areas of S. Paulo and Santos, Brazil, were analysed in order to determine their hygienic and sanitary conditions. Fecal coliformes, fecal streptococci, sulfite reducer clostridia and Salmonella were searched for the purpose of evaluating sanitary conditions, and total coliforms, heterotrophic bacteria, proteolitic and lipoli-tic microorganisms for evaluating hygienic conditions. In some samples, nitrate levels were also determined. It was discovered that these waters do not present adequate sanitary and higienic conditions and that, in some cases, nitrate levels were extremelly high (75.7 mg/l). In most samples, higher levels of fecal streptococci and sufite reducer clostridia than fecal coliforms were detected, which seems to show that the two former indicators would be more appropriate for evaluating the sanitary conditions of this kind of water. Salmonella were detected in only one of 44 samples analysed and coliphages in none. In the stastistical analysis, the correlation matrix showed significant correlations among three fecal pollution indicators, as well as among anaerobic and aerobic heterotrophs and lipolitic bacteria. A direct relationship between the deterioration of water quality and the geological and hydrogeological conditions of the environment studied was observed. When cemiteries are constructed these conditions should, therefore, be taken into consideration.

Foram analisadas amostras de águas subterrâneas de três cemitérios localizados em áreas geologicamente distintas de São Paulo e de Santos, Brasil, com relação às condições higiênicas e sanitárias. Para as primeiras foram considerados os coliformes totais, bactérias heterotróficas, microrganismos proteolíticos e lipolíticos. Para as sanitárias foram pesquisados coliformes fecais, estreptococos fecais, clostrídios sulfito redutores, colifagos e salmonelas. Verificou-se que as águas não apresentaram condições higiênicas satisfatórias e, em alguns casos, foram encontrados niveis altos de nitrato (75,7 mg/l). A deteção de níveis mais elevados de estreptococos fecais e de clostrídios sulfito redutores em relação aos coliformes fecais, na maior parte das amostras, parece mostrar que os dois primeiros indicadores seriam mais adequados para avaliação das condições sanitárias deste tipo de água. Foi detectada Salmonella apenas em uma amostra e não foram detectados colifagos. Na análise estatística, foram encontradas correlações significantes entre três indicadores de poluição fecal assim como entre as contagens em placas de bactérias heterotróficas aeróbias, anaeróbias e lipolíticas. Foi observada uma relação direta entre a deterioração da qualidade da água e as condições geológicas e hidrogeológicas do ambiente estudado, devendo este fator ser considerado para o planejamento e implantação de cemitérios.

Groundwater samples collected by piezometers from three cemiteries in geologically distinct areas of S. Paulo and Santos, Brazil, were analysed in order to determine their hygienic and sanitary conditions. Fecal coliformes, fecal streptococci, sulfite reducer clostridia and Salmonella were searched for the purpose of evaluating sanitary conditions, and total coliforms, heterotrophic bacteria, proteolitic and lipoli-tic microorganisms for evaluating hygienic conditions. In some samples, nitrate levels were also determined. It was discovered that these waters do not present adequate sanitary and higienic conditions and that, in some cases, nitrate levels were extremelly high (75.7 mg/l). In most samples, higher levels of fecal streptococci and sufite reducer clostridia than fecal coliforms were detected, which seems to show that the two former indicators would be more appropriate for evaluating the sanitary conditions of this kind of water. Salmonella were detected in only one of 44 samples analysed and coliphages in none. In the stastistical analysis, the correlation matrix showed significant correlations among three fecal pollution indicators, as well as among anaerobic and aerobic heterotrophs and lipolitic bacteria. A direct relationship between the deterioration of water quality and the geological and hydrogeological conditions of the environment studied was observed. When cemiteries are constructed these conditions should, therefore, be taken into consideration.