Resumen Este trabajo adopta las teorías de los stakeholders y de la masa crítica para estudiar la relación entre la participación de mujeres en el consejo y el desempeño financiero de empresas cotizadas en México (ROA, ROE, liquidez y precio de la acción). La investigación contribuye a la literatura latinoamericana en el ámbito de la diversidad de género y el gobierno corporativo. A través de un panel de datos y una muestra de estudio conformada por 667 observaciones-año durante el periodo 2013- 2019, los resultados demuestran un limitado avance de la representación de mujeres en los consejos de administración; pasando de un 5% en 2013 a un 7% en 2019, es decir, apenas un incremento de 2% en los últimos seis años; mientras que solamente el 4.5% de las empresas cuentan con al menos tres mujeres participando en los consejos. El análisis econométrico muestra que la presencia de mujeres en el consejo incrementa la rentabilidad sobre el capital (ROE), aunque su efecto no es significativo en la rentabilidad sobre los activos (ROA), la liquidez o el precio de la acción. Es necesario generar estrategias y leyes que motive a una mayor representación de mujeres en los consejos.

Abstract This paper adopts the stakeholder and the critical mass theories to study the relationship between the female participation on the boards and the financial performance of listed firms in Mexico (RoA, RoE, liquidity and share price). The research contributes to the Latin American literature in the field of gender diversity and corporate governance. Through a panel data and a sample of study composed bt 667 year- observations during the 2013-2019 period, the results show a limited progress of the female representation on the boards; going from 5% in 2013 to 7% in 2019, that is, just an increase of 2% in the last six years; while only 4.5% of the companies have at least three women participating in the boards. Econometric analysis shows that the presence of women on the board increases return on equity (ROE), although its effect is not significant on return on assets (ROA), liquidity or share price. It is necessary to generate strategies and laws that motivate to a higher representation of women on the boards.

ABSTRACT Background: Antibiotic resistance is considered to be the next worldwide epidemic. Urinary tract infections (UTI) are the second most common cause of infection, which also has the highest resistance frequency. Nevertheless, in high Andean regions, little is known about the antibiotic resistance. Objectives: Determine the antimicrobial resistance patterns of the enterobacteriaceae family isolated from urinary tract infections of a Peruvian Andean region. Methods: A retrospective cross-sectional review of 1717 records from the microbiology service of a private health institution from Puno - Peru, was done between the years 2014 and 2017. Antibiotic resistance by uropathogens was studied among different age groups. Statistical analysis included Chi2 test with a p<0.05. Poisson regression was used to calculate the prevalence ratio (PR) with a 95% confidence interval. Findings: There was a wide distribution of antibiotic resistance among all the antibiotics, mainly in Escherichia coli and Proteus spp. The elderly had the highest prevalence of antibiotic resistance. As age increased, resistance to all drugs also increased (p<0.01). Furthermore, the elderly had a risk probability of resistance of 1.22, 1.42, 1.20 and 1.32 to penicillins, cephalosporins, quinolones and other antibiotics respectively. Conclusion: The antimicrobial resistance patterns of the Peruvian Andean region were lower than national and international patterns.

RESUMEN Introducción: La resistencia a antibióticos es considerada la próxima epidemia mundial. Las infecciones del tracto urinario (ITU) son la segunda causa más común de infecciones y la que presenta mayor frecuencia de resistencia. Sin embargo, poco se ha reportado en regiones altos-andinas. Objetivo: Evaluar los patrones de resistencia antimicrobiana de la familia enterobacteriaceae aisladas de infecciones del tracto urinario de pacientes ambulatorios de una región altoandina peruana y sus factores asociados. Material y Métodos: Estudio transversal analítico retrospectivo, a partir de 1717 registros del Servicio de Microbiología de una institución de salud en la región Puno - Perú, entre los años 2014 al 2017. Se estudió la resistencia a antibióticos según uropatógeno en diferentes grupos etarios. Se empleó la prueba de Chi2 de Pearson y un modelo de regresión de de Poisson para calcular la razón de prevalencias (RP). En todos los análisis se consideró un valor de p<0.05 como significativo y se estimaron intervalos de confianza al 95%. Resultados: Se presentó una amplia distribución de resistencia en todos los fármacos evaluados, siendo mayor en Escherichia coli y Proteus spp. El grupo etario, ≥ 60 años, presentó la mayor prevalencia de resistencia bacteriana. A medida que la edad aumentaba, la resistencia a todos los fármacos estudiados también aumentó (p <0.01). Así mismo, los pacientes ≥ 60 años presentaron mayor probabilidad de presentar resistencia bacteriana a penicilinas, cefalosporinas y quinolonas. Conclusión: El patrón de resistencia a los antibióticos utilizados en ITUs en la zona altoandina peruana incrementa con la edad.

Resumen En Chile, los estudiantes con discapacidad intelectual (DI) asisten a escuelas especiales o a escuelas regulares con programas de integración escolar (PIE). Hasta la fecha se carece de información respecto de las oportunidades de aprendizaje (ODA) que se proporcionan a estos estudiantes en ambos contextos. El estudio que se presenta es parte de una investigación mayor, cuyo propósito es explorar las ODA de las matemáticas que se generan en centros de educación especial para estudiantes con DI. Se realizaron entrevistas semiestructuradas con profesores y directivos de escuelas especiales, con el objetivo de indagar cuáles son sus creencias sobre la enseñanza, sobre los estudiantes con DI y las matemáticas. Los resultados indican que la enseñanza a estudiantes con DI requiere de mucho tiempo de planificación, de un currículo flexible que se adapte a las necesidades individuales, de uso de material concreto y de una evaluación individualizada. Respecto de los estudiantes, los entrevistados indican que no hay fórmulas generales y que se debe tratar cada caso de manera individual. Finalmente, profesores y directivos estiman que la enseñanza de las matemáticas para estudiantes con DI son principalmente el conteo y las operaciones con números, lo cual excluye del currículo ofrecido espacios para el desarrollo de otras habilidades matemáticas.

Abstract In Chile, students with learning disabilities (LD) attend either special schools or regular schools with school integration programs (SIP). To this day, there is no information about the learning opportunities (LO) provided to these students in both contexts. The study is part of a larger research aimed at exploring the mathematics LO for students with LD in special education centers. We conducted semi-structured interviews with teachers and principals from special schools with the purpose of learning about their beliefs on teaching, students with LD, and math. Results show that teaching students with LD requires many hours of planning, a flexible curriculum adapted to their individual needs, using specific material, and individualized assessment. Regarding students, the respondents note that there are no general formulas and that each case should be handled individually. Finally, the school teachers and principals estimate that the teaching of mathematics for students with LD includes mainly counting and operations with numbers, which excludes spaces for developing other mathematical abilities from the curriculum offered.

Resumo No Chile, os estudantes com deficiência intelectual (DI) frequentam escolas especiais ou escolas normais com programas de integração escolar (PIE). Até agora não existem dados sobre as oportunidades de aprendizagem (ODA) proporcionadas aos estudantes nos dois contextos. O estudo apresentado faz parte de uma pesquisa maior, cujo propósito é explorar as ODA das matemáticas que são geradas em centros de educação especial para estudantes com DI. Realizaram-se entrevistas semiestruturadas com professores e diretivos de escolas especiais, com o objetivo de indagar quais são suas crenças sobre o ensino, sobre os estudantes com DI e as matemáticas. Os resultados assinalam que o ensino a estudantes com DI precisa de muito tempo de planejamento, de um currículo flexível que possa ser adaptado às necessidades individuas, de uso de material concreto e de uma avaliação individualizada. Em relação com os estudantes, os entrevistados indicam que não existem fórmulas gerais e que cada caso deve ser trabalhado individualmente. Finalmente, professores e diretivos consideram que o ensino das matemáticas para estudantes com DI consiste principalmente na contagem e as operações com números, o que exclui do currículo oferecido espaços para o desenvolvimento de outras habilidades matemáticas.

BACKGROUND: Pervasive introductions of non-native taxa are behind processes of homogenization of various types affecting the global flora and fauna. Chile's freshwater ecosystems encompass a diverse and highly endemic fish fauna that might be sensitive to the introduction of non-native species, an ongoing process that started two centuries ago, but has to date received little attention. Using historical (native) and present-day (native and non-native) presence-absence data sets of compositional similarity, our goal was twofold: (1) evaluate patterns of taxonomic homogenization at various spatial scales and (2) identify clusters of widely versus narrowly distributed species to assess their relative role in compositional changes. We expect that non-native species with wide distributions might have a larger influence in taxonomic homogenization than those with narrow distributions. RESULTS: Chile's fish assemblages have become increasingly homogenized during the last two centuries when evaluating changes in compositional similarity among 201 watersheds (65.3 % of total comparisons showed homogenization) distributed among six defined biotic units. Taxonomic differentiation was significantly more prevalent than taxonomic homogenization within biotic units. Among biotic units, comparisons between historical and current compositional similarity were all significantly different. We identified one cluster of non-native fishes that were distributed across the entire five or six biotic units. This cluster included Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss) as the two most representative species. A second cluster we identified included fishes such that on average spanned only one or two biotic units. CONCLUSIONS: We provide first evidence for an ongoing and large-scale process of taxonomic homogenization among Chile's watersheds occurring at various scales. Our findings provide taxonomic and biogeographic baseline information for management plans and courses of action for conservation of native fishes, many of which are endemic. We also discuss management guidelines of non-native fishes in Chile. Baseline information of both native and non-native fish taxa might be applicable to other isolated regions elsewhere.

Introduced juvenile Chinook salmon (Oncorhynchus tshawytscha) have been found co-occurring with native fishes in the Allipén River, Chile. Due to this co-occurence, the microhabitat use, microhabitat preferences, and overlap between juvenile Chinook salmon and the native catfish, Trichomycterus areolatus, were examined during the summer and fall of 2007-2008. Microhabitat preferences and overlap between juvenile Chinook salmon and the native catfish were determined using the Instream Flow Incremental Methodology and the Pianka´s index. Juvenile Chinook salmon and the native catfish microhabitat preferences varied seasonally showing a high degree of similarity and overlap between the species (higher than 80%). The results suggest the risk of negative interactions and interactive segregation over habitat processes between juvenile Chinook salmon and native catfish. As a consequence, the Chinook salmon invasion may threaten the stability of native catfish populations at Allipén River.

Juveniles del salmón Chinook (Oncorhynchus tshawytscha) introducido en el sur de Chile han sido observados co-ocurriendo con peces nativos en el río Allipén, Chile. Con objeto de identificar las potenciales implicancias ecológicas de esta invasión sobre la fauna íctica nativa, durante el verano y otoño de los años 2007-2008, se determinaron las preferencias y grado de solapamiento de microhábitat entre el salmón Chinook y el pez nativo bagre, Trichomycterus areolatus. Las preferencias y grado de solapamiento de microhábitat entre el salmón Chinook y el bagre se determinaron utilizando el método incremental para la asignación de caudales mínimos y el índice Pianka. En ambas especies, las preferencias de microhábitat variaron estacionalmente mostrando además un alto grado de similitud y solapamiento (mayor al 80%). Los resultados obtenidos sugieren una potencial interacción negativa entre el salmón Chinook y el bagre a través de una segregación interactiva por hábitat. De este modo, el actual proceso de invasión del salmón Chinook en el sur de Chile representaría una amenaza para la estabilidad de las poblaciones de bagre en el río Allipén.

In order to describe the developmental biology of the tick Argas neghmei Kohls & Hoogstraal under laboratory conditions, 40 females and 40 males were collected from chicken coops located in Calama (II Region, Chile). They were fed on chickens and maintained under two laboratory conditions: one group at 30 ± 5 ºC and 35 ± 5 % RH and another at 27 ± 5 ºC and 80 ± 5 % RH, both at 12: 12 h L:D photoperiod. The ticks were observed daily to determine larval feeding periods, preoviposition, oviposition, egg incubation as well as the frequency of egg laying, number of eggs laid, and percentage of larval hatching. Females did not lay eggs at 80 ± 5% RH, and data on the biology of this tick was obtained only at 35 ± 5% RH. The life cycle of A. neghmei lasted an average of 269 days. Feeding period of each nymphal stage as well as of adult females between oviposition events lasted less than a day. Females laid on average 1.8 egg batches and egg-laying period lasted on average 14 days, during which about 96 eggs were laid per female.

Given the importance of nitrogen fertilization in the production of tulip (Tulipa gesneriana L.) bulbs and the limited information relative to this crop in Chile, a study was conducted to characterize its growth and nitrogen uptake. Tulips were cultivated outdoors and included two deflorations. Bulbs of the variety negrita, 7-9 cm, were planted. A randomized complete blocks design was used with five treatments: 0, 70, 120, 160 and 200 kg N ha-1 and three replications. Periodically, plants were sampled to analyze their growth and N content. Accumulation of dry matter and N of the entire crop and individual plants were not significantly affected (p>0.05) by nitrogen fertilization, undoubtedly because of the high N supply from the soil. However, bulbs increased N concentration at harvest (p<0.05) and reached marketable size. Daily growth rates and N uptake by plants and individual organs exhibited similar patterns. Nitrogen fertilization should be divided: in early winter to promote later leaf expansion and then in full spring to cover the period of maximum crop growth and N uptake.

Dada la importancia de la fertilización nitrogenada en la producción de bulbos de tulipán (Tulipa gesneriana L.) y la limitada información relacionada con este cultivo en Chile, se realizó un ensayo para caracterizar su crecimiento y absorción de nitrógeno. El cultivo se realizó al aire libre e incluyó dos desbotonaduras. Se plantaron bulbos variedad negrita, tamaño 7-9 cm y se usó un diseño de bloques completos al azar con cinco tratamientos: 0, 70, 120, 160 y 200 kg N ha-1 y tres repeticiones. Se realizaron muestreos periódicos de plantas para analizar su crecimiento y contenido de N. La acumulación de materia seca y N del cultivo y de órganos individuales no fue afectada significativamente (p>0.05) por la fertilización nitrogenada, debido seguramente a un alto suministro de N del suelo. Sin embargo, los bulbos aumentaron su concentración de N a la cosecha (p<0.05) y alcanzaron un tamaño comercial. Las tasas diarias de crecimiento y absorción de N de plantas y órganos individuales presentaron patrones similares. La fertilización nitrogenada debiera fraccionarse: temprano en el invierno para promover la posterior expansión foliar, y luego en plena primavera para cubrir el período de máximo crecimiento y absorción de N del cultivo.