ABSTRACT Environmental surveillance of water sources is important to monitoring viral hepatitis transmission in clinical settings. This study investigated the circulation of hepatitis A (HAV) and E (HEV) viruses in sewage and clinical samples from Argentina. Between 2016 and 2017, 80 raw sewage samples and 86 clinical samples (stool and serum) from suspected cases of hepatitis A and hepatitis E were obtained. HAV and HEV were tested by both real-time and nested PCR. Positive samples were sequenced for genotype determination and phylogenetic analysis. Overall, HAV was recovered in 39% of sewage samples and 61.1% of clinical samples. HEV was detected in 22.5% of sewage samples and 15.9% of clinical samples. HAV was found more frequently in sewage during the winter and in clinical samples in spring; HEV was more prevalent in sewage during summer and in clinical samples in autumn. All HAV isolates belonged to genotype IA and HEV isolates belonged to genotype 3, the most prevalent genotypes in South America. High prevalence of HAV and HEV in environmental and clinical samples in Mendoza, Argentina was observed. These findings reinforce the importance of environmental surveillance and implementation of health strategies to control the spread of HAV and HEV in developing countries.

Abstract Coronary artery disease (CAD) and ischemic heart disease (IHD) are often indistinctly used terms. Both combined have generated, over the past years, concerns about sex disparities in their presentation. From an epidemiological perspective, females have several disadvantages regarding the prevention, diagnosis, and treatment of CAD. Most of the general cardiovascular risk factors affect women more frequently, or with a higher morbidity and mortality association. Besides, atypical manifestations of the disease and uncommon forms of CAD represent a diagnostic challenge for clinicians. Even if current treatments for CAD have no apparent sex bias, women representation in clinical trials and treatment patterns analyzed in clinical practice refuse this statement. Several disparities are caused by inevitable sex-particularities, but many of them are more social, cultural, and dogmatic beliefs that have to be addressed and overhaul. (CAD IHD (IHD terms generated years presentation perspective prevention diagnosis frequently association Besides clinicians bias statement sexparticularities, sexparticularities particularities, particularities sex-particularities social cultural overhaul

Since the onset of the COVID-19 pandemic, scientists and health care workers provided information based on scientific evidence for the general public, increasing their exposure on social and mainstream media. Society witnessed science-in-the-making while scientists and health care workers were dedicated to improve understanding and develop tools for the diagnosis, treatment, prevention and control of this novel disease. This study aims to assess the impact of the ongoing COVID-19 pandemic on adolescents’ perception of science, scientists and health care workers; to understand whether it changed their career choices; and to learn about the resulting first-year applications and enrollments in scientific and medical careers for the 2020-2021 school year in Mexico. We conducted a voluntary national anonymous online survey and analyzed the official database of the National Association of Universities and Higher Education Institutions in Mexico (ANUIES) to answer these questions. With 983 valid responses (CI 95%) we found that by mid-2021, 9 out of 10 respondents aged 14-19 in Mexico had a positive perception of science; that the ongoing pandemic improved their perception of science (69%), scientists (70%) and health care workers (72%); and that their experience during the pandemic changed their career choices to pursue science (23%) and health care (28%) careers. The selected main reason (40-50%) for studying science and health care careers was “liking that type of knowledge”; while only 3% agreed that the pandemic was the main reason for their choice. A thorough analysis of the official ANUIES database showed an increase in first-year applications for scientific (22%) and health care (17%) careers for the 2020-2021 school year compared to the previous, non-pandemic 2019-2020 school year. Enrollment was partly limited by the number of places available. With this study we conclude that a silver lining of the COVID-19 pandemic could be the improvement of the perception of science, scientists and health care workers and possibly, the creation of a new generation of scientists, medical doctors, and health care workers. Future studies would need to investigate the duration and further positive consequences of this pandemic effect and to understand whether these results are consistent in other parts of the world where adolescents experienced different public policies, public messages and COVID-19 outcomes.

ABSTRACT Fluvial systems are the most threatened ecosystems in the world by the development of anthropogenic activities. Advancing in the knowledge of the ecology of these systems is the basis for the creation of adequate management measures for the conservation of these systems. This study provides relevant background information on the structure of macroinvertebrate and fish assemblages in six tributary rivers of the Biobío River Basin, a basin characterised by high hydrological alteration and fragmentation index. Our results describe a good environmental condition in the rivers evaluated, with the Lirquén, Quilme and Mininco rivers standing out as water courses with a high richness and diversity of macroinvertebrate and fish species. Structurally, these rivers are a refuge for native fish species classified as Endangered (Nematogenys inermis, Bullockia maldonadoi, Percilia irwini, Diplomystes nahuelbutaensis). In this sense, the fundamental role of these as reservoirs of species and the importance at basin level of maintaining the connectivity of these tributaries with the main course, and not only the conservation of each river in a segregated way, is pointed out.

RESUMEN Los sistemas acuáticos continentales son los ecosistemas más amenazados del mundo por el desarrollo de actividades antropogénicas. Avanzar en el conocimiento de la ecología de estos sistemas, es la base para la creación de medidas de manejo adecuadas para la conservación de estos sistemas. Este estudio, proporciona antecedentes relevantes de la estructura de los ensambles de macroinvertebrados y peces en seis ríos tributarios de la cuenca del río Biobío, caracterizada por una alta alteración hidrológica e índice de fragmentación. Nuestros resultados describen una buena condición ambiental en los ríos evaluados, destacando los ríos Lirquén, Quilme y Mininco, como cursos de agua con alta riqueza y diversidad de especies de macroinvertebrados y peces. De manera estructural, estos ríos constituyen un refugio para especies de peces nativas catalogadas en categorías de conservación En Peligro (Nematogenys inermis, Bullockia maldonadoi, Percilia irwini, Diplomystes nahuelbutaensis). En este sentido, se señala el rol fundamental de estos como reservorios de especies y la importancia a nivel de cuenca de mantener la conectividad de estos tributarios con el curso principal, y no solo la conservación de cada río de manera segregada.

Abstract Purpose: Fama-French model (FFM) has been successful in helping to predict the financial markets, but investors have been interested in creating more sophisticated models to better predict the performance of the stock market. The objective of the extended version is to create a more robust econometric model to better predict the performance of the Mexican Stock Market. Design/methodology/approach: The study divides the Mexican Stock Market into six different portfolios. The criteria to build those portfolios are the same one used in Fama-French (1992). The study comprises 78 stocks listed in the Mexican Stock Market that are analyzed monthly during 1997-2018. The study analyzes the period before and after the 2008-2009 financial crisis to identify whether there are important changes. The estimation applies the traditional and an extended version of the FFM that include macroeconomic variables such as country risk, economic activity, inflation rate, and exchange rate and some financial variables recommended in the literature. Findings: Results indicate that classic FFM variables are statistically significant in most cases, but relevant macroeconomic variables such as the interest rate, exchange rate and country risk stand out for being weakly relevant in most of the portfolios. However, it is noticed that some of these macroeconomic variables became relevant for different portfolios only after the 2008-2009 crisis, especially in portfolios which include small market capitalization firms. Research limitations/implications: The study includes the stocks listed in the Mexican Stock Market. One limitation is the small number of stocks available, which reduces the possibility of creating well diversified portfolios. This study includes 78 stocks. The stocks removed from the sample are from firms that were not listed during six consecutive months or whose market capitalization did not change in the same period. Outlier data were removed from the sample to capture in better way the general performance of the stock market. Practical implications: The objective of the extended version is to create a more robust econometric model than the traditional model. It is expected that such estimations can be helpful to investors to make better decisions when they try to predict performance in the stock market. Social implications: An extended version of the FFM can be helpful to investors to make better decisions when they try to predict performance in the stock market. Originality/value: To the best of our knowledge there are no more studies in the literature of the Mexican financial market that apply the same methodology.

Abstract This study analyzes the exchange rate pass-through effect on the Consumer Price Index (CPI) in Mexico's main border and 27 non-border metropolitan cities. The period examined includes monthly data from January 2002 to December 2019. A vector autoregressive model (VAR) is used, which includes formal employment at the city level as a proxy to economic development, interest rates, nominal exchange rates, each analyzed city’s CPI, U.S. consumer prices, energy commodity prices and control variables such as service sector employment share and large firm employment share. Impulse response functions are constructed. Results for the 2002-2016 period indicate that exchange rate changes primarily affect border cities. Different arguments are included to justify such results. Pass-through values are also found to increase in general for all cities when the period 2017-2019 (January 2017 when important gasoline price shocks started previous its price liberalization in December 2017) is included in the regressions.

Resumen Se estudia el efecto traspaso del tipo de cambio en el Índice de Precios al Consumidor (INPC) en áreas metropolitanas fronterizas y 27 no-fronterizas de México. El periodo abarca de enero 2002 a diciembre 2019 y se utilizan datos mensuales. Se emplea un modelo de vectores autoregresivos (VAR), que incluye empleo formal a nivel ciudad como proxy del desempeño económico, tasas de interés, tipo de cambio nominal, índices de precios de cada ciudad analizada, el índice de precios en USA, precios de commodities de energía y variables de control como el peso de los servicios y la participación de empresas grandes en el empleo de cada ciudad. Funciones de impulso respuesta son construidas. Los resultados para 2002-2016 indican que el tipo de cambio afecta en mayor intensidad a las ciudades fronterizas. Se incluyen diversos argumentos que justifican dichos resultados. Se encuentra adicionalmente, que los valores de traspaso aumentan en forma general cuando se incluye 2017-2019, periodo donde en enero de 2017 comenzaron importantes variaciones en el precio de la gasolina, previo a su liberalizacion en diciembre de 2017.

Abstract Litsea parvifolia is an ever-green shrub of the Lauraceae family whose foliar biomass is its main component. Its leaves are harvested and marketed in and around the southeastern region of Saltillo municipality, Coahuila State. Fresh, it has culinary and medicinal use; dry, it is used as condiment. In order to regulate its use and determining its stock, an allometric model was selected to estimate the dry foliar biomass and the elaboration of a production table of the standing shrubs was planned as well. Natural populations were evaluated, recording the total height (H, cm) and mean diameter (Dp, cm) of the shrub crown, considering all categories of height and cover of standing shrubs and dry leaf biomass (Bfs, g). Ten allometric models were evaluated using the PROC MODEL procedure in SAS, version 9.4. Dp and H are correlated with laurel Bfs. The Schumacher-Hall model in its non-linear form is statistically reliable (p <0.0001) as it records the best statistics, with presence of heteroscedasticity, corrected effect with a weighted regression with variance structure (Dp 2 H) -0.5 , obtaining an R 2 aj . of 0.82, S xy of 18.41 g and a CV of 44.93 %. The model can be used to estimate the production of Bfs in places with similar ecological characteristics to the study area.

Resumen Litsea parvifolia es un arbusto, perenne de la familia Lauraceae, cuya biomasa foliar es su componente principal. Sus hojas se aprovechan y comercializan en el sureste de Saltillo y alrededores. En fresco, tiene uso culinario y medicinal; en seco, como condimento. Con el propósito de generar información básica para la regulación de su aprovechamiento, se planteó seleccionar un modelo alométrico para predecir la biomasa foliar seca y elaborar una tabla de producción para arbustos en pie. Se evaluaron algunas poblaciones naturales, en las que se registró la altura total (H) y diámetro promedio (Dp) de todos los individuos en pie y se determinó la biomasa foliar seca (Bfs). Se probaron nueve modelos alométricos mediante el procedimiento PROC MODEL en SAS 9.4, para elegir aquel con el mayor coeficiente de determinación ajustado ( R 2 a j .); el valor más bajo en la raíz cuadrada media del error ( R C M E), en el coeficiente de variación ( C V) y en la suma de cuadrados de los residuales (SCR); además de la significancia de sus parámetros ( P ≤ 0.05). El Dp y la H se correlacionaron con la Bfs. El modelo Schumacher-Hall no lineal es confiable estadísticamente (p < 0.0001), registra los mejores estadísticos, con presencia de heteroscedasticidad, efecto corregido con regresión ponderada con estructura de varianza (Dp 2 H) -0.5 , una R 2 Aj . de 0.82, S xy de 18.41 g y un CV de 44.93 %. El modelo puede usarse para predecir la producción de Bfs en sitios con características ecológicas similares al área de estudio.

Abstract Background: Fragmentation (establishment of barriers e.g., hydropower dams, reservoirs for irrigation) is considered one of the greatest threats to conservation of river systems worldwide. In this paper we determine the fragmentation status of central Chilean river networks using two indices, namely Fragmentation Index (FI) and Longest Fragment (LF). These are based on the number of barriers and their placement as well as river length available for fish movement. FI and LF were applied to eight Andean river basins of central Chile in order to assess their natural, current (2018) and future (2050) fragmentation at the doorstep of a hydropower boom. Subsequently, we exemplify the use of these indices to evaluate different placement scenarios of new hydropower dams in order to maximize hydropower use and at the same time minimize impact on fish communities. Results: In the natural scenario 4 barriers (waterfalls) were present. To these 4 barriers, 80 new ones of anthropogenic origin were added in the current (2018) scenario, whereas 377 new barriers are expected in near future (2050). Therefore, compared to the ‘natural’ scenario, in 2050 we expect 115-fold increase in fragmentation in analysed river systems, which is clearly reflected by the increase of the FI values in time. At the same time, the LF diminished by 12% on average in the future scenario. The fastest increase of fragmentation will occur in small and medium rivers that correspond to 1st, 2nd and 3rd Strahler orders. Finally, case study on configuration of potential hydropower plants in the Biobio basin showed that hydropower output would be maximized and negative effects on fish communities minimised if new hydropower plants would be located in tributaries of the upper basin. Conclusions: Fragmentation of Chilean Andean river systems is expected to severely increase in near future, affecting their connectivity and ecological function as well as resilience to other anthropogenic stressors. Indices proposed here allowed quantification of this fragmentation and evaluation of different planning scenarios. Our results suggest that in order to minimise their environmental impact, new barriers should be placed in tributaries in the upper basin and river reaches above existing barriers.

Resumo Objetivo Os sistemas fluviais do Chile central são curtos, íngremes e fluem rapidamente. Eles são caracterizados por regimes de descarga dominados por chuvas e neve derretida. A fauna de invertebrados desses sistemas fluviais é altamente endêmica. O objetivo do presente estudo foi descrever a estrutura da comunidade de invertebrados em oito sistemas fluviais na região central do Chile (33-39°S), utilizando co-ocorrência de espécies e modelos nulos de compartilhamento de nichos. Métodos Amostras de invertebrados foram coletadas de rios chilenos centrais (33-39 ° S), os dados foram analisados com as espécies de coocorrência e os modelos nulos de compartilhamento de nichos para determinar potenciais padrões de estruturação. Resultados Os resultados revelaram a presença de padrões não estruturados em coocorrência, considerando cada local, bem como todos os locais, que é mais provavelmente um efeito da presença de muitas espécies repetidas nos locais estudados. A sobreposição de nicho revelou a existência de competição interespecífica em cada local e entre locais Os resultados obtidos para estes sistemas fluviais corroboram observações dos rios patagônicos chilenos. Conclusão O presente estudo contribui para a compreensão dos padrões biogeográficos e ecológicos das comunidades de invertebrados nos rios da região central do Chile e, como tal, constitui a base para estudos ecológicos mais complexos.

Abstract Aim River systems of Central Chile are short, steep and fast flowing. They are characterized by discharge regimes dominated by rainfall and snowmelt. Invertebrate fauna is highly endemic. This study aimed to describe the community structure of invertebrate in eight river systems in Central Chile (33-39°S) using species co-occurrence and niche sharing null models. Methods Invertebrate samples were collected from Central Chilean rivers (33-39°S), data were analyzed co-occurrence species and niche sharing null models for determine potential structuring patterns. Results The results revealed the presence of non-structured patterns in co-occurrence considering each site as well as all sites, that is most probably an effect of presence of many repeated species in the studied sites. Furthermore, we found the existence of niche overlap due to interspecific competition at each site and among all sites. The results obtained from these river systems corroborate observations from Chilean Patagonian Rivers. Conclusion This study contributes to understanding of biogeographical and ecological patterns of invertebrate communities in central Chilean Rivers and provide foundations for more complex ecological studies.

ABSTRACT We document movement patterns and home range of Diplomystes camposensis, an endemic and threatened freshwater catfish from Chile. We tracked the movements of seven individuals of different body size (13.5 to 19 cm SL) using portable radio telemetry equipment to investigate movement patterns in relation to day/night activity and habitat use in the San Pedro River (Valdivia Basin). Tracked movements and model-based analyses revealed that D. camposensis has a large home range and high mobility. The average home range was 0.068163 ± 0.033313 km2, and the average area of higher activity was 0.005646 ± 0.011386 km2. The mean linear home range was 387.4 m. The results also showed that movements were longer during the night, supporting nocturnal habits. Movements tended to be in an upstream direction for some individuals, although these differences were not significant when data was pooled. Large home range and movements suggest that the species may require large river areas to meet ecological demands, an aspect that could be severely affected by fragmentation. These results, along with previously published genetic data, suggest that the conservation of D. camposensis would be seriously threatened by hydromorphological alterations (e.g. lack of connectivity), such as those resulting from dam building.

RESUMEN En este trabajo documentamos patrones de movimiento y estimación de ámbito de hogar de Diplomystes camposensis, un siluriforme endémico y amenazado del Sur de Chile. Por medio de radio telemetría, se monitorearon 7 individuos con un rango de tamaño entre 13.5 y 19 cm de longitud estándar, para evaluar patrones de movimiento con respecto al uso de hábitat y tiempo de actividad (dia/noche) en la zona del Río San Pedro, Cuenca del Río Valdivia. Los resultados muestran que D. camposensis tiene un ámbito de hogar grande y una alta movilidad. El ámbito de hogar fue de 0.068163 ± 0.033313 km2 con un área promedio de mayor actividad de 0.005646 ± 0.011386 km2. El ámbito de hogar lineal medio fue de 387.4 m. Los resultados también mostraron que la especie presenta una mayor actividad por la noche y una tendencia hacia un mayor flujo de movimiento en dirección aguas arriba, aunque esto último no fue significativo. Un ámbito de hogar grande y su alta movilidad sugieren que la especie podría requerir de amplias zonas del río para satisfacer sus demandas ecológicas. Al igual que estudos previos con datos genéticos, estos resultados sugieren que la especie D. camposensis se vería perjudicada por alteraciones en la hidromorfología del cauce (e.g. falta de conectividad) tales como aquellas que resulten de la construcción de represas.

Abstract: Cryoablation is an energy alternative to radiofrequency for ablation of various arrhythmias, where its unique biophysical properties offer a greater safety profile. Since its first use for the surgical treatment of different arrhythmias until its conceptualization in the current technical transcatheter, cryoablation has proven not to be only a safe source of energy, but also an effective source in the long-term. While the radiofrequency has been the energy most used for isolation of pulmonary veins in atrial fibrillation ablation, technological advances in cryoballon have managed to simplify the procedure without sacrificing its effectiveness. Cryoablation has been widely used for arrhythmias located in high-risk locations, such as the ablation of the atrioventricular nodal reentrant tachycardia and septal accessory pathways, due to its theoretical null risk of complete AV block. This review intends to give the clinical applications of the cryothermy through a thorough understanding of their biophysical basis.

Resumen: La crioablación es una energía alternativa a la radiofrecuencia para la ablación de diferentes arritmias, en la que sus propiedades biofísicas únicas ofrecen un perfil de seguridad mayor. Desde su utilización para el tratamiento quirúrgico de diversas arritmias hasta su conceptualización en la técnica transcatéter actual, la crioablación ha probado no solo ser una fuente segura de energía, sino una fuente eficaz a largo plazo. Mientras que la radiofrecuencia ha sido la energía más utilizada para el aislamiento de venas pulmonares en la ablación de fibrilación auricular, los avances tecnológicos con criobalón han logrado simplificar el procedimiento sin sacrificar su eficacia. La crioablación ha sido ampliamente utilizada para arritmias localizadas en sitios de alto riesgo, como la ablación de la taquicardia por reentrada intranodal AV y vías accesorias septales por su nulo riesgo teórico de bloqueo AV completo. Esta revisión tiene la intención de dar a conocer las aplicaciones clínicas de la criotermia a través del entendimiento profundo de sus bases biofísicas.

This work was undertaken to investigate the effect of variations of the feed rate on a fed-batch set-up used to degrade xenobiotics. The mixture of substrates was composed of PCP, 2,4,6 TCP and 2,3,5,6 TeCP (pentachlorophenol, 2,4,6 trichlorophenol and 2,3,5,6 tetrachlorophenol respectively). Two acclimated bacteria isolated from soil were used: Pseudomonas aeruginosa and Achromobacter sp. nov. The different flow rates tested were: I: 0.5 m·ℓmin¹, II: 1.67 m·ℓmin¹ and III: 2.00 m·ℓmin-1. Our results show that during fed-batch operation the 2,4,6 TCP exhibits an earlier degradation than the other compounds, for all of the flow rates tested. This indicates that in this case the degradation of the most recalcitrant compounds (PCP and 2,3,5,6 TeCP) is benefited by the increase in biomass of bacteria, due to the metabolisation of a less recalcitrant compound (2,4,6 TCP). The defined parameter, specific degradation rate (SDR), was demonstrated to be very useful for comparing the degradation abilities at different flow rates of a fed-batch system. The degradation efficiencies were shown to be higher than 90% for all of the cases and to decrease as the feed rate increases. However, the SDR, a parameter that involves the rate of degradation and the biomass, increases as the flow rate increases. At a feed flow rate of 2 m·ℓmin-1 SDR reaches a maximum of 12.476 x 10-10 mgCP-h-1-CFU-1. Finally, among the feed flows tested, taking into account both the degradation efficiency and the SDR, 2 m·ℓmin-1 is the most convenient flow rate for chlorophenol degradation in fed-batch systems. An even higher degradation efficiency (97%) can be achieved by using the feed rate of 2 m·ℓmin-1 followed by an additional batch post-treatment of 2 h, with a SDR of 13.136 x 10-10 mg CP-h-1-CFU-1.

En el presente artículo se describe el uso del aceite de higuerilla como combustible alternativo en motores diesel. Para este fin, se obtiene biodiesel a partir de aceite de higuerilla mediante el proceso de transesterificación. Se prueban tres mezclas de biodiesel (B5%, B10% y B20%) en un motor diesel, para el cual se midieron los siguientes parámetros: la potencia, el consumo de combustible, la temperatura del motor, y los gases de combustión;las mezclas fueron caracterizadas mediante la densidad, viscosidad, índice de refracción y calor de combustión. Se determinó que el uso del aceite de higuerilla en la mezcla genera un aumento en la viscosidad y el consumo de combustible, además también influye en la reducción del poder calorífico, potencia del motor, los gases de combustión como el CO y CO2, los óxidos de azufre, los hidrocarburos, la opacidad en los humos del escape del motor y ocasiona un equilibrio en el rendimiento observado en el motor diesel, manifiesto en las temperaturas del motor.

Castor oil trans esterification has been evaluated as a source of alternative biodiesel. Three mixtures of biofuel (B5% B10% and B20%) were tested in a diesel engine. Power, fuel consumption, temperature and exhaust emissions were measured. Also, densities, viscosities, refractive indexes and combustion heats of the mixtures were determined. The use of biodiesel mixtures produces an increase of viscosity and fuel consumption, decreasing the heating and engine power, reducing the combustion gases like CO, CO2, sulfur oxides, hydrocarbons, and lowering the opacity of exhaust emissions. Additionally, a balance in the observed diesel engine performance was evidenced by the engine temperatures.