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Wastewater treatment and simultaneous production of value-added products with microalgae represent a sustainable alternative. Industrial wastewater, characterized by high C/N molar ratios, can naturally improve the carbohydrate content in microalgae without the need for any external source of carbon while degrading the organic matter, macro-nutrients, and micro-nutrients. This study aimed to understand the treatment, reuse, and valorization mechanisms of real cooling tower wastewater (CWW) from a cement-processing industry mixed with domestic wastewater (DW) to produce microalgal biomass with potential for synthesis of biofuels or other value-added products. For this purpose, three photobioreactors with different hydraulic retention times (HRT) were inoculated simultaneously using the CWW-DW mixture. Macro- and micro-nutrient consumption and accumulation, organic matter removal, algae growth, and carbohydrate content were monitored for 55 days. High COD (> 80%) and macronutrient removals (> 80% of N and P) were achieved in all the photoreactors, with heavy metals below the limits established by local standards. The best results showed maximum algal growth of 1.02 g SSV L-1 and 54% carbohydrate accumulation with a C/N ratio of 31.24 mol mol-1. Additionally, the harvested biomass presented a high Ca and Si content, ranging from 11 to 26% and 2 to 4%, respectively. Remarkably, big flocs were produced during microalgae growth, which enhanced natural settling for easy biomass harvesting. Overall, this process represents a sustainable alternative for CWW treatment and valorization, as well as a green tool for generating carbohydrate-rich biomass with the potential to produce biofuels and fertilizers.

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OBJECTIVES: To determine the time to reverse transcription-polymerase chain reaction (RT-PCR) negativity after the first positive RT-PCR test, factors associated with longer time to RT-PCR negativity, proportion of children seroconverting after proven severe acute respiratory syndrome coronavirus 2 infection, and factors associated with the lack of seroconversion. STUDY DESIGN: The Epidemiological Study of Coronavirus in Children of the Spanish Society of Pediatrics is a multicenter study conducted in Spanish children to assess the characteristics of coronavirus disease 2019. In a subset of patients, 3 serial RT-PCR tests on nasopharyngeal swab specimens were performed after the first RT-PCR test, and immunoglobulin G serology for severe acute respiratory syndrome coronavirus 2 antibodies was performed in the acute and follow-up (<14 and ≥14 days after diagnosis) phase. RESULTS: In total, 324 patients were included in the study. The median time to RT-PCR negativity was 17 days (IQR, 8-29 days), and 35% of patients remained positive more than 4 weeks after the first RT-PCR test. The probability of RT-PCR negativity did not differ across groups defined by sex, disease severity, immunosuppressive drugs, or clinical phenotype. Globally, 24% of children failed to seroconvert after infection. Seroconversion was associated with hospitalization, persistence of RT-PCR positivity, and days of fever. CONCLUSIONS: Time to RT-PCR negativity was long, regardless of the severity of symptoms or other patient features. This finding should be considered when interpreting RT-PCR results in a child with symptoms, especially those with mild symptoms. Seroprevalence and postimmunization studies should consider that 11 in 4 infected children fail to seroconvert.

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La pandemia por COVID-19 generó un gran impacto en la salud mental en los profesionales de salud y más aún por los que trabajan en primera línea. El objetivo principal fue conocer el impacto psicológico estado ansiedad y depresión en trabajadores de salud frente al covid-19 en el cantón La Troncal. Se realizó un estudio descriptivo, corte transversal, correlativo, comparativo, con enfoque cuantitativo, los datos fueron secundarios (n=100), se evaluó la Escala de Ansiedad y Depresión de Goldberg (GADS). Se realizó un análisis descriptivo mediante porcentajes, frecuencias, medidas de tendencia central y percentiles, también se hizo un análisis de diferencia de medias de dos grupos mediante la prueba t de Student para muestras independientes y el coeficiente de correlación de Pearson (r), encontrando edad media de la población es 34.57 años, tiempo medio que labora dentro de la institución 4.63 años, participó mayoritariamente el género femenino (n=70), Enfermeras (n=37), lugar de trabajo en iguales condiciones. En cuanto a la ansiedad está presente (n=81), pero la depresión está ausente (n=89). En género tienen igual ansiedad y depresión, el centro de salud Tipo C tiene mayor nivel de ansiedad. Y entre la ansiedad y el tiempo que labora una relación negativa (r= -0.2), es decir a mayor tiempo que labora dentro de la institución menor es el nivel de ansiedad. En conclusión, se debe realizar programas de intervención para disminuir los problemas de salud mental en los profesionales del cantón la Troncal.

The COVID-19 pandemic generated a great impact on the mental health of health professionals and even more so for those working on the front line. The main objective was to know the psychological impact of the state of anxiety and depression in health workers in the canton of La Troncal. A descriptive, cross-sectional, correlative, comparative, quantitative, cross-sectional study was carried out with a quantitative approach, the data were secondary (n=100), and the Goldberg Anxiety and Depression Scale (GADS) was evaluated. A descriptive analysis was carried out using percentages, frequencies, measures of central tendency and percentiles, an analysis of the difference of means of two groups was also made using Student's t-test for independent samples and Pearson's correlation coefficient (r), finding that the mean age of the population was 34.57 years, mean time working in the institution was 4.63 years, the majority of participants were women (n=70), nurses (n=37), workplace in the same conditions. Anxiety is present (n=81), but depression is absent (n=89). In gender have equal anxiety and depression, Type C health center has higher level of anxiety. There is a negative relationship (r= -0.2) between anxiety and working time, i.e. the longer the time spent working in the institution, the lower the level of anxiety. In conclusion, intervention programs should be carried out to reduce mental health problems among professionals in the canton of La Troncal.

A pandemia COVID-19 teve um grande impacto sobre a saúde mental dos profissionais de saúde, especialmente aqueles que trabalham na linha de frente. O principal objetivo era determinar o impacto psicológico da covid-19 nos trabalhadores da saúde no cantão de La Troncal em termos de ansiedade e depressão. Um estudo descritivo, transversal, correlacional, comparativo, quantitativo, transversal foi realizado com uma abordagem quantitativa, os dados eram secundários (n=100), e a Escala de Ansiedade e Depressão Goldberg (GADS) foi avaliada. Uma análise descritiva foi realizada utilizando porcentagens, freqüências, medidas de tendência central e percentis, uma análise da diferença entre as médias de dois grupos também foi realizada utilizando o teste t de Student para amostras independentes e o coeficiente de correlação de Pearson (r), encontrando a idade média da população em 34,57 anos, o tempo médio de trabalho na instituição em 4,63 anos, a maioria dos participantes eram mulheres (n=70), enfermeiras (n=37), e o local de trabalho estava nas mesmas condições. A ansiedade está presente (n=81), mas a depressão está ausente (n=89). No gênero, eles têm ansiedade e depressão iguais, o centro de saúde tipo C tem um nível mais alto de ansiedade. Existe uma relação negativa entre ansiedade e tempo de trabalho (r= -0,2), ou seja, quanto maior o tempo de trabalho na instituição, menor é o nível de ansiedade. Em conclusão, devem ser implementados programas de intervenção para reduzir os problemas de saúde mental entre os profissionais do cantão de La Troncal.

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This study aimed to investigate a mixed microalgae culture's capacity to simultaneously remove nutrients and organic matter from industrial effluents while producing carbohydrate-rich biomass. A culture initially dominated by filamentous cyanobacteria Geitlerinema sp. was inoculated in a lab-scale stirred tank photobioreactor, operating at 10, 8, and 6 days hydraulic retention time (HRT). The results show that different HRT led to different inorganic carbon profiles and N:P ratios in the culture, influencing microbial changes, and carbohydrate content. Hence, higher N-NH4+ removal efficiencies were obtained at HRT of 10 d and decreased with decreasing HRT. Whereas, complete depletion of P-PO43- was achieved only at HRT of 8 d and 6 d. Also, the highest COD removal efficiency (60%) was achieved at 6 d of HRT. The maximum accumulation of carbohydrates was achieved at HRT of 8 d, which presented an N:P ratio of 22:1 and carbon availability, recording a constant carbohydrate content of 57% without any additional carbon source. Furthermore, this operational condition reached the best biomass production of 0.033 g L-1d-1 of easy-settling cyanobacteria dominated culture. According to the results, this process presents an alternative to recycling industrial effluents and, at the same time, grow valuable biomass, closing a loop for sustainable economy.

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Microbial mineralization of atrazine was characterized in soils and liquid media in the presence of nitrogen fertilizer concentrations representing typical field applications. The mineralization of atrazine in soils varied between 6 and 99% after 18 d of incubation. Half-lives of between 0.99 and more than 18 d were obtained. Mineralization kinetics and degree are related by a reciprocal trend to concentrations of available nitrogen in the soil. In liquid media, half-lives were calculated as 0.12 d in the absence of fertilizer nitrogen and as 79 d in the presence of 1,000 mg/L of KNO3-N. Only 20% of atrazine was mineralized after 18 d of incubation in the presence of this concentration of KNO3-N, whereas greater than 90% mineralization occurred after 2 d of incubation in liquid medium without KNO3-N. The results demonstrate that the mineralization of atrazine is inhibited even at fertilizer nitrogen levels lower than typical field applications. Inhibition in soil is lower than that in liquid medium, possibly because of the higher complexity of the soil system. This may explain why atrazine that infiltrates to the groundwater is persistent. The microbial consortium of the soils was characterized, and seven species were identified. The degrading capacity of these species suggests that only three species are involved in the degradation of atrazine.

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