The effect of ability-grouping techniques on students' perceptions of speaking tasks

Tesis (Profesor de Inglés para la Enseñanza Básica y Media, Licenciado en Educación)Un problema crítico en la enseñanza del Inglés como Lengua Extranjera en Chile es que la mayoría de los profesores no pueden interactuar con sus alumnos del colegio usando el lengua meta. Lo anterior corresponde a una falta de oportunidades de los estudiantes para practicar la habilidad de hablar a través de conversaciones y trabajo colaborativo. De acuerdo a esto, agrupar a los alumnos precisamente en clases ha demostrado incentivar dichas oportunidades. Por lo tanto, ya que el consenso en técnicas de agrupación es controversial, el presente estudio apunta a contrastar las percepciones de los alumnos de acuerdo a agrupaciones de habilidades homogéneas y heterogéneas comparando dos segundos medios en un colegio chileno subvencionado. Por una parte el Grupo A fue organizado homogéneamente de acuerdo a sus competencias en el idioma mediante una prueba de diagnóstico para que los estudiantes con nivel similar estuvieran juntos. Por otra parte, el Grupo B fue organizado heterogéneamente para que los estudiantes con diferentes niveles estuvieran juntos. Este experimento siguió un diseño de comparación y fue utilizado un instrumento correspondiente a un cuestionario con una escala Likert para medir las percepciones de los estudiantes de acuerdo a las técnicas de agrupación. La aplicación consistió en seis clases para ambos grupos en tratamiento, las cuales incluyeron los seis tipos de actividades colaborativas de tres tipos diferentes de tarea. Las actividades y sus respectivos tipo de actividades son, de la primera a la última: “Juego de Roles” y “Entrevista” (Tarea Interpersonal), “Quién soy yo” y “Debate” (Tarea Transaccional), “Contar una Historia” y “Presentación de Afiche” (Tarea Extensiva). Consecuentemente, el principal hallazgo del estudio muestra que todos los estudiantes (ambos grupos, A y B) percibieron las técnicas de agrupación positivamente. Finalmente, contrastando ambas técnicas de agrupación, los estudiantes del Grupo B (heterogéneo) percibieron la mayor parte de las actividades más positivamente que el Grupo A (homogéneo)One critical problem in Chilean EFL teaching is that most teachers cannot interact with school learners using the target language. The latter corresponds to a shortage of opportunities for learners to practice the speaking skill through conversation and collaboration. Accordingly, grouping learners accurately in classes have proved to encourage the referred opportunities. Therefore, since consensus on grouping techniques is controversial, the current study aimed to contrast learners‟ perceptions on Homogeneous and Heterogeneous ability-grouping by comparing two tenth grade courses in a Chilean subsidized school. On the one hand, Group A was arranged homogeneously in compliance with learners‟ low, middle, or high ability level diagnosed in an oral pretest, so learners with similar level were together. On the other hand, Group B was arranged heterogeneously so learners with different levels were gathered. This experiment followed a comparison-group design and used as an instrument a questionnaire with a Likert scale to measure learners‟ perceptions on grouping techniques. The application consisted on six lessons for both treatment groups, which featured six different collaborative activities taken from three different types of tasks. The activities and their respective type of task are, from first to last: Role Play and Interview (Interpersonal tasks), Who am I and Debate (Transactional tasks), Story Telling and Poster Presentation (Extensive tasks). Consequently, the main finding of the study shows that all learners (from both, Groups A and B) perceived grouping techniques positively. Finally, when contrasting both grouping techniques, learners from Group B (Heterogeneous) perceived most of the activities more positively than Group A (Homogeneous)

Free radical scavenging and cytotoxic activity of five commercial standardized extracts (red wine, green tea, pine bark, polygonum and pomegranate)

The objective of extract standardization is to obtain optimum and consistent quality of herbal preparations with defined components. This paper presents the radical scavenging effect of extracts against DPPH free radical (2,2-diphenyl-1-picrylhydrazyl) and cytotoxic activity in vitro on the cervical cancer cell line HeLa of five commercial standardized extracts rich in phenolic compounds: red wine (Vitis vinifera), green tea (Camellia sinensis), pine bark (Pinus maritime), polygonum (Polygonum cuspidatum), and pomegranate (Punica granatum). It shows radical scavenging activity in the following order, according to their median effective concentration (EC<sub50): P. cuspidatum 85 µg/ml, C. sinensis 11 µg/ml, P. maritima 7 µg/ml, V. vinifera 6 µg/ml, P. granatum 1 µg/ml and for positive control, vitamin E was 21 µg/ml. The cytotoxic activity, according to their half maximal inhibitory concentration (IC50) was: P. granatum 22 µg/ml, C. sinensis 13.4 µg/ml, P. cuspidatum 12.8 µg/ml, P. maritima 11 µg/ml, and V. vinifera 7 µg/ml and for positive control, Triton X-100 was 3 µg/ml. Our results indicate that low concentrations of red wine, pomegranate, and pine bark extracts have high radical scavenging effect as well as cytotoxic activity on HeLa cells. Therefore, these extracts may be an important source for phytopharmaceuticals development.Key words: Radical scavenging, cytotoxicity, HeLa cells, standardized extracts

Antibacterial and Antibiofilm Activity of Methanolic Plant Extracts against Nosocomial Microorganisms

Biofilm is a complex microbial community highly resistant to antimicrobials.The formation of biofilms in biotic and abiotic surfaces is associated with high rates of morbidity and mortality in hospitalized patients. New alternatives for controlling infections have been proposed focusing on the therapeutic properties of medicinal plants and their antimicrobial effects. In the present study the antimicrobial and antibiofilm activities of 8 methanolic plant extracts were evaluated against clinical isolated microorganisms. Preliminary screening by diffusion well assay showed the antimicrobial activity of Prosopis laevigata, Opuntia ficus-indica, and Gutierrezia microcephala. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined ranging from 0.7 to >15 mg/mL. The specific biofilm formation index (SBF) was evaluated before and after the addition of plant extracts (MBC × 0.75). Opuntia ficus-indica caused the major reduction on SBF in dose-dependent manner. Cytotoxic activity of plant extracts was determined using brine shrimp lethality test (Artemia salina L.). Lethal Dose concentration (LD50 values) of the plant extracts was calculated. LD50 values for P. laevigata and G. microcephalawere 141.6 and 323.

Estudio de la actividad biológica de los extractos de tres plantas de la familia Boraginaceae

Tesis (Doctor en Ciencias con Acentuación en Química de productos Naturales) UANL, 2010.UANLhttp://www.uanl.mx

Antiurolithic activity of Berberis trifoliate extract on induced urolithiasis in rats by zinc disc implantation

Background: In clinical therapy, there is no satisfactory drug available for treatment of urolithiasis, especially for the prevention of their recurrence. The aim of this work was to evaluate in vivo antiurolithic activity of methanolic extract of Berberis trifoliata leaves.Material and methods: Urolithiasis was induced in Wistar rats by zinc disc implantation in urinary bladder. Upon postsurgical recovery, different doses of the methanolic extract of B. trifoliata leaves (50, 100 and 150 mg/kg body weight) were administered orally to zinc disc implanted rats for a period of 20 days. Antiurolithiatic activity was evaluated by measuring the difference between the weight of the implanted zinc discs at the time of implantation and the final weight of the dried calculi taken out from the bladder at the end of the 20 days period of treatment.Results: Extract of B. trifoliata significantly reduced calculi deposition around the implanted zinc disc at all doses (50, 100, and 150 mg/kg).Conclusion: Treatment with methanolic extract of B. trifoliata is useful agent against the kidney stone formation.Keywords: Antiurolithic, Berberis trifoliata, urolithiasis, zinc disc implantation

Protocolos de atendimento da avulsão de dentes permanentes em crianças

A lesão de avulsão, por definição, é o deslocamento completo de um dente para fora do seu alvéolo, devido a traumas acidentais ou não acidentais. Desta forma, é considerada como a saída de uma peça dentária, cortando o fornecimento de sangue pulpar e expondo as células do ligamento periodontal ao ambiente externo. É importante que o clínico tenha conhecimento dos protocolos de tratamento para dentes traumatizados, a fim de que se realize um tratamento de maneira adequada, e com isso aumentar a hipótese de sucesso, embora não se possa garantir um prognóstico favorável a longo prazo. Para isso, a Associação Internacional de Traumatologia Dental (IADT) propõe um guia atualizado para orientar os profissionais. O objetivo deste trabalho foi realizar uma revisão sistemática integrativa sobre a avulsão de dentes permanentes, adquirir informações sobre etiologia, protocolos de tratamento emergente e contínuo, possíveis sequelas e prognósticos. Foi realizada uma pesquisa sumariada e analisada, sobre a avulsão de dentes permanentes em crianças, através das bases de dados: PuBmed, Medline, Google Acadêmico, SciELO e livros de especialidade Odontopediatria dos últimos quinze anos. Com a finalidade de extrair conclusões da evidência científica procurada. Foram identificados treze artigos os quais foram selecionados para sua leitura na integra e incluídos no presente trabalho de investigação. Pode-se concluir que os Médicos Dentistas devem conhecer os protocolos atualizados dos tratamentos da avulsão dentária na dentição permanente de forma a atuar corretamente em situações de urgência, com vista a um prognóstico favorável

Bactericidal Activity, Isolation and Identification of Most Active Compound from 20 Plants used in Traditional Mexican Medicine Against Multidrug-Resistant Bacteria

Abstract Background and Objective: Plants are used in Mexico as traditional medicine for the treatment of diverse illnesses such as stomach pain, fever, diarrhea, insomnia, flu and other respiratory diseases. Twenty were selected to determine their bactericidal activity. The aim of this study was the isolation of molecules from plants used in Mexican traditional medicine. Materials and Methods: Using chromatographic procedures, the responsible bactericidal molecules from rosemary was extracted and then identified by spectroscopic analysis IR, 1H NMR, 13C NMR, DEPT, HSQC and GC-MS. Measures of central tendency were determined by statistical analysis. Results: Ten of these plants showed bactericidal activity against multidrug-resistant bacteria. This biological activity was reported for Carya illinoensis against Pseudomonas aeruginosa , also for Equisetum robustum , Stevia rebaudiana and Castela texana against Methicillin resistant Staphylococcus aureus (MRSA). The methanolic extract of Rosmarinus officinalis (rosemary) showed important bactericidal activity against MRSA (ATCC BAA-44) and clinically isolated MRSA. Conclusion: Rosemary’s bactericidal molecules were isolated and then identified as a mixture of betulinic, oleanolic and ursolic acid (MIC = 725 µg mLG1). Key words: Rosmarinus officinalis , multidrug-resistance, MRSA, thin layer chromatography, flash chromatography, 1H NMR, 13C NMR, triterpenic acid

Psychological health in Chilean women based on the history of mistreatment

AbstractIn this paper we have studied the circumstances of violence and the influence of social support in the mental health of a sample of 97 Chilean women. The results highlighted the importance of perceived social support on the health of women. It was concluded that living with the person responsible for the aggressions predicts better mental health than the abandonment of the relationship by either one

Predictive methodology of the dynamics of the number of COVID-19 cases: application to China, Belgium, and South Korea

Objetivos: Se han desarrollado múltiples metodologías basadas en la teoría de la probabilidad para establecer predicciones de epidemias de dengue, malaria, VIH, obesidad, entre otras. Esta investigación tuvo como objetivo desarrollar un nuevo método de predicción de la dinámica del número de casos de COVID-19 para China, Bélgica y Corea del Sur, basado en la teoría de la probabilidad que permite evaluar y comparar su crecimiento.   Materiales y métodos: Se establecieron rangos de probabilidad del número de casos de COVID-19, los cuales fueron asignados a cada uno de los valores diarios del número de casos de COVID-19 reportados por China Bélgica y Corea del Sur evaluados durante 74, 50 y 50 días, respectivamente. Se calculó la frecuencia y probabilidad de cada rango diario para cada país. Se calculó su probabilidad total y la probabilidad de la dinámica en intervalos de 8 días consecutivos y se compararon los valores entre países para evaluar sus diferencias.   Resultados: se establecieron valores de probabilidad de 1.21E-30, 2.03E-22 y 3.15E-12 para China, Bélgica y Corea del Sur, lo que permite diferenciar cuantitativamente las características de su dinámica. Las diferencias de probabilidad de los subespacios de 8 días variaron de 0,003 a 1, lo que permitió evaluar los cambios temporales en la dinámica.   Conclusión: los rangos establecidos para la evaluación del número de casos de COVID-19 permiten diferenciar el comportamiento de las epidemias entre países y estratificar la severidad de la expansión, destacando un orden matemático subyacente para este fenómeno que permite predecir cuantitativamente su dinámica espacio-temporal y indirectamente, la eficacia de las políticas de salud pública implementadas para cada país.Objectives: Multiple methodologies based on probability theory have been developed to establish predictions of dengue, malaria, HIV, obesity epidemics, among others. This research aimed to develop a new method for predicting the dynamics of the number of COVID-19 cases for China, Belgium, and South Korea based on the probability theory that allows the evaluation and comparison of their increment. Material and methods: Probability ranges of the number of COVID-19 cases were established, which were assigned to each of the daily number of COVID-19 cases reported by China, Belgium, and South Korea that were evaluated during 74, 50, and 50 days respectively. The frequency and probability of each daily range for each country was calculated. Their total probability and the probability of the dynamics in intervals of 8 consecutive days were calculated, and the values between countries were compared to evaluate their differences. Results: Probability values of 1.21E-30, 2.03E-22, and 3.15E-12 were established for China, Belgium, and South Korea, which allows the quantitative differentiation of the characteristics of their dynamics. The probability differences of the 8-day subspaces ranged from 0.003 to 1, allowing the temporal changes in the dynamics to be evaluated. Conclusion: The ranges established for the evaluation of the number of COVID-19 cases allow to differentiate the behavior of epidemics between countries and to stratify the severity of expansion. Highlighting an underlying mathematical order for this phenomenon permitted quantitatively predict its spatiotemporal dynamic and indirectly, the efficacy of public health politics implemented for each country

Predictive methodology of the dynamics of the number of COVID-19 cases: application to China, Belgium, and South Korea

Objetivos: Se han desarrollado múltiples metodologías basadas en la teoría de la probabilidad para establecer predicciones de epidemias de dengue, malaria, VIH, obesidad, entre otras. Esta investigación tuvo como objetivo desarrollar un nuevo método de predicción de la dinámica del número de casos de COVID-19 para China, Bélgica y Corea del Sur, basado en la teoría de la probabilidad que permite evaluar y comparar su crecimiento.   Materiales y métodos: Se establecieron rangos de probabilidad del número de casos de COVID-19, los cuales fueron asignados a cada uno de los valores diarios del número de casos de COVID-19 reportados por China Bélgica y Corea del Sur evaluados durante 74, 50 y 50 días, respectivamente. Se calculó la frecuencia y probabilidad de cada rango diario para cada país. Se calculó su probabilidad total y la probabilidad de la dinámica en intervalos de 8 días consecutivos y se compararon los valores entre países para evaluar sus diferencias.   Resultados: se establecieron valores de probabilidad de 1.21E-30, 2.03E-22 y 3.15E-12 para China, Bélgica y Corea del Sur, lo que permite diferenciar cuantitativamente las características de su dinámica. Las diferencias de probabilidad de los subespacios de 8 días variaron de 0,003 a 1, lo que permitió evaluar los cambios temporales en la dinámica.   Conclusión: los rangos establecidos para la evaluación del número de casos de COVID-19 permiten diferenciar el comportamiento de las epidemias entre países y estratificar la severidad de la expansión, destacando un orden matemático subyacente para este fenómeno que permite predecir cuantitativamente su dinámica espacio-temporal y indirectamente, la eficacia de las políticas de salud pública implementadas para cada país.Objectives: Multiple methodologies based on probability theory have been developed to establish predictions of dengue, malaria, HIV, obesity epidemics, among others. This research aimed to develop a new method for predicting the dynamics of the number of COVID-19 cases for China, Belgium, and South Korea based on the probability theory that allows the evaluation and comparison of their increment. Material and methods: Probability ranges of the number of COVID-19 cases were established, which were assigned to each of the daily number of COVID-19 cases reported by China, Belgium, and South Korea that were evaluated during 74, 50, and 50 days respectively. The frequency and probability of each daily range for each country was calculated. Their total probability and the probability of the dynamics in intervals of 8 consecutive days were calculated, and the values between countries were compared to evaluate their differences. Results: Probability values of 1.21E-30, 2.03E-22, and 3.15E-12 were established for China, Belgium, and South Korea, which allows the quantitative differentiation of the characteristics of their dynamics. The probability differences of the 8-day subspaces ranged from 0.003 to 1, allowing the temporal changes in the dynamics to be evaluated. Conclusion: The ranges established for the evaluation of the number of COVID-19 cases allow to differentiate the behavior of epidemics between countries and to stratify the severity of expansion. Highlighting an underlying mathematical order for this phenomenon permitted quantitatively predict its spatiotemporal dynamic and indirectly, the efficacy of public health politics implemented for each country