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Cultural eutrophication is the leading cause of water quality degradation worldwide. The traditional monitoring of eutrophication is time-consuming and not integrative in space and time. Here, we examined the use of carbon (δ13C) and nitrogen (δ15N) isotopic composition to track the degree of eutrophication in a bay of Lake Titicaca impacted by anthropogenic (urban, industrial and agricultural wastewater) discharges. Our results show increasing δ13C and decreasing δ15N signatures in macrophytes and suspended particulate matter with distance to the wastewater source. In contrast to δ15N and δ13C signatures, in-between aquatic plants distributed along the slope were not only affected by anthropogenic discharges but also by the pathway of carbon uptake, i.e., atmospheric (emerged) vs aquatic (submerged). A binary mixing model elaborated from pristine and anthropogenic isotope end-members allowed the assessment of anthropogenically derived C and N incorporation in macrophytes with distance to the source. Higher anthropogenic contribution was observed during the wet season, attributed to enhanced wastewater discharges and leaching of agricultural areas. For both seasons, eutrophication was however found naturally attenuated within 6 to 8 km from the wastewater source. Here, we confirm that carbon and nitrogen stable isotopes are simple, integrative and time-saving tools to evaluate the degree of eutrophication (seasonally or annually) in anthropogenically impacted aquatic ecosystems.

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Monomethylmercury (MMHg) concentrations in aquatic biota from Lake Titicaca are elevated although the mercury (Hg) contamination level of the lake is low. The contribution of sediments to the lake MMHg pool remained however unclear. In this work, seven cores representative of the contrasted sediments and aquatic ecotopes of Lake Titicaca were sliced and analyzed for Hg and redox-sensitive elements (Mn, Fe, N and S) speciation in pore-water (PW) and sediment to document early diagenetic processes responsible for MMHg production and accumulation in PW during organic matter (OM) oxidation. The highest MMHg concentrations (up to 12.2 ng L-1 and 90% of THg) were found in subsurface PWs of the carbonate-rich sediments which cover 75% of the small basin and 20% of the large one. In other sediment facies, the larger content of OM restricted MMHg production and accumulation in PW by sequestering Hg in the solid phase and potentially also by decreasing its bioavailability in the PW. Diagenetically reduced S and Fe played a dual role either favoring or restricting the availability of Hg for biomethylation. The calculation of theoretical diffusive fluxes suggests that Lake Titicaca bottom sediments are a net source of MMHg, accounting for more than one third of the daily MMHg accumulated in the water column of the Lago Menor. We suggest that in the context of rising anthropogenic pressure, the enhancement of eutrophication in high altitude Altiplano lakes may increase these MMHg effluxes into the water column and favor its accumulation in water and biota.

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En este artículo se presentan las cifras de prevalencia de los problemas de alcoholismo a los que se enfrenta el médico general en México. Estas cifras se basan en las investigaciones que se han llevado a cabo en el Instituto Mexicano de Psiquiatría (IMP). Posteriormente se comenta el papel que se el médico general puede desempeñar en la prevención secundaria de los problemas relacionados con el consumo de alcohol. Por último, se informa brevemente sobre un proyecto de investigación que la Organización Mundial de la Salud (OMS) estás coordinando en once países y en el cual participa México, por intermedio del IMP. Desde hace varios años, el IMP realiza estudios epidemiológicos para conocer la prevalencia de los trastornos psiquiátricos en la práctica médica general. Los ha efectuado en diversos medios que abarcan diferentes contextos socioculturales, como son los centros de salud de la Secretaría del mismo nombre (SSA), las unidades familiares del Instituto Mexicano del Seguro Social (IMSS) y un hospital general privado, el Hospital Español; los primeros atienden a la población económicamente más desamparada; los del IMSS, a obreros y trabajadores asalariados, y el último, a personas de las clases sociales media, media alta y alta. Los estudios han seguido el clásico diseño epidemiológico inglés, que se devide en dos etapas. Las primera emplea como procedimiento de tamizaje (screening) o de identificación de los casos psiquiátricos, un cuestionario autoaplicable. La segunda consiste en confirmar la existencia de los casos psiquiátricos y en establecer un diagnóstico de acuerdo con la clasificación de enfermedades de la OMS. En la primera etapa se utilizó el Cuestionário General de Salud de Goldberg y en la segunda, una entrevista psiquiátrica estructurada del mismo autor...

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The present paper reports the most relevant results from an epidemiologic survey that was carried out in a hospital's general practice service in Mexico. The survey comprises several issues such-as: the validity and standardization of the General Health Questionnaire (GHQ), a screening instrument, designed for the early detection of mental disorders, which is validated against the clinical criteria expressed through the Standardized Psychiatric Interview (SPI), the prevalence of psychiatric disorders which includes type of syndromes and affected subgroups, the relation between the ratings of the SPI and the scales of the GHQ (somatic symptoms, sleep disturbances, social disfunction and severe depression) with demographic variables. From the population attending the service during a period of 5 weeks, a total of 619 patients, to whom the GHQ was administered, were randomly selected. From this sample 364 patients were separately interviewed by means of the SPI. No significant differences were found between the sample and the population regarding age, sex, and educational level. The prevalence of mental disorders obtained for the mixed population was of 34%, being of 26% for men and of 36% for women. The only risk factor found for both populations was the low educational level of the head of the family. In the multiple regression analysis, significant differences were found among some groups in spite of the low predictive power of the studied variables.

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En la presente investigación llevada a cabo en México, en la consulta externa de un hospital general en un período de 5 semanas, se reportanlos resultados más relevantes sobre: la validez y estandarización de un instrumento de detección temprana de casos, el Cuestionario General de Salud (CGS), utilizando como criterio de validez externa la Entreviosta Psiquiátrica Estandarizada (EPE); la prevalencia de transtornos psiquiátricos, grupo diagnóstico y subgrupos afectados; la relación entre las puntuaciones obtenidas entre la EPE y las subescalas de CGS (AU)

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RESUMO

En la presente investigación llevada a cabo en México, en la consulta externa de un hospital general en un período de 5 semanas, se reportanlos resultados más relevantes sobre: la validez y estandarización de un instrumento de detección temprana de casos, el Cuestionario General de Salud (CGS), utilizando como criterio de validez externa la Entreviosta Psiquiátrica Estandarizada (EPE); la prevalencia de transtornos psiquiátricos, grupo diagnóstico y subgrupos afectados; la relación entre las puntuaciones obtenidas entre la EPE y las subescalas de CGS

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RESUMO

The present paper reports the most relevant results from an epidemiologic survey that was carried out in a hospitals general practice service in Mexico. The survey comprises several issues such-as: the validity and standardization of the General Health Questionnaire (GHQ), a screening instrument, designed for the early detection of mental disorders, which is validated against the clinical criteria expressed through the Standardized Psychiatric Interview (SPI), the prevalence of psychiatric disorders which includes type of syndromes and affected subgroups, the relation between the ratings of the SPI and the scales of the GHQ (somatic symptoms, sleep disturbances, social disfunction and severe depression) with demographic variables. From the population attending the service during a period of 5 weeks, a total of 619 patients, to whom the GHQ was administered, were randomly selected. From this sample 364 patients were separately interviewed by means of the SPI. No significant differences were found between the sample and the population regarding age, sex, and educational level. The prevalence of mental disorders obtained for the mixed population was of 34

, being of 26

for men and of 36

for women. The only risk factor found for both populations was the low educational level of the head of the family. In the multiple regression analysis, significant differences were found among some groups in spite of the low predictive power of the studied variables.

RESUMO

Se comparo la eficacia del medico general con la del Cuestionario General de Salud de Goldberg en el descubrimiento de trastornos emocionales en la poblacion que asiste a la consulta externa de un hospital general. De la frecuencia total (33.3%) de trastornos emocionales estimada para esta poblacion, el medico general descubrio unicamente 15.9%, lo cual permitio identificar la tendencia del mismo hacia la sobreestimacion de los sujetos sin trastornos. El Cuestionario General de Salud mostro mayor eficacia al descubrir 25.6% de los pacientes con trastornos emocionales. Los resultados favorecen la utilizacion de instrumento como el cuestionario como medida de apoyo para el medico en el descubrimiento de trastornos mentales

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