Counteracting Epistemicide: Social and Cultural Capital of Teachers in a Dual Language Program

This case study explored the social and cultural capital of teachers in a rural Midwestern Spanish-English dual-language immersion (DLI) program as they overcame an Anglocentric epistemological hegemony in their daily practice. Working from Bourdieu’s (1986) theory of social capital and Rios-Aguilar and Kiyama’s (2012) approach to funds of knowledge, this research demonstrated that DLI teachers faced challenges ranging from resistance by non-DLI teachers in the school afraid of losing their jobs, to a broader fear of the DLI program taking resources away from the monolingual anglophone classrooms. To overcome these challenges, the DLI teachers drew extensively on their global social networks to resuscitate knowledge systems under attack from an Anglocentric epistemology, leveraging their existing social and cultural capital to benefit the community as a whole through an authentic Spanish-language epistemology

Aprendizaje de la física por resolución de problemas: Caso de estudio en Alcalá de Henares, España (A physics problem- based- learning: Case study in Alcalá de Henares, Spain)

Se aplicó el método de aprendizaje por resolución de problemas en Física a alumnos de institutos de educación secundaria de Alcalá de Henares, España. La principal dificultad que se encuentra es que los alumnos realizan las operaciones de forma automática y no son capaces de explicar cuáles son los pasos que siguen para intentar resolver un problema y muchas veces tampoco saben por qué eligen esos pasos. Todos los grupos de alumnos dedican la mayor parte del tiempo a la realización de cálculos matemáticos. La estrategia más repetida es la de buscar los datos numéricos del problema. Consiste en leer el enunciado, identificar los datos, buscar la fórmula a emplear, reemplazar y obtener el resultado numérico. El porcentaje de alumnos que realiza la comprensión de la situación aumenta desde el segundo año, donde es bajo, hasta tercer año, donde se puede considerar satisfactorio. Los resultados también indican que existe una baja realización de acciones en los indicadores que miden la capacidad de analizar las condiciones de aplicación de las leyes o principios y la de comprobar si se cumplen las condiciones de aplicación. Se deduce que esto puede indicar una falta de comprensión del significado físico de las leyes y principios. El análisis y verificación de los resultados es el paso que registra menor número de realización, seguido del análisis del marco teórico. AbstractTo solve problems in Physics, we applied the Problem-Based Learning technique to students from secondary education institutes in Alcalá de Henares, Spain. The main difficulty which was found is that the students carried out their calculations automatically without being able to explain the steps they had followed in order to solve a problem. And even more , they often were unaware of why they chose such steps. All groups of students spent most of the time carrying out mathematical calculations. The most repetitive strategy was the one that required the extraction of numerical data from a problem. It consisted of reading the statement, identifying the data, finding the formula to apply, replacing in the data and obtaining the numerical result. The percentage of students who managed to understand the situation rose from the second year, when it was low, to the third year when it could be considered satisfactory. The results also indicated that there was a low realization of the actions related to the activity indicators analyzing the conditions of applying the laws or principles and verifying if the application conditions were fulfilled. We deduce that this can indicate a lack of understanding of the Physics law and principle meanings The analysis and verification of the results is the step which shows a lower amount of realization, followed by the analysis of the theoretical framework

Factorial structure and reliability of the academic satisfaction questionnaire on Chilean medical students

Indexación: Web of Science; Scopus.El presente estudio analiza la estructura factorial y confiabilidad del cuestionario de satisfacción académica (CSA) en una muestra de 563 estudiantes de medicina, entre 19 y 29 años (media de 20,42); provenientes de cuatro universidades chilenas. Una vez finalizada la traducción al castellano se exploró la validez de contenido de los ítems mediante un juicio de expertos. La estructura factorial del cuestionario se analizó a través de un análisis factorial exploratorio empleando el método Análisis de Ejes Principales (AEP). Los resultados preliminares de la fiabilidad y validez del instrumento han mostrado que la estructura de un factor es viable y adecuada de acuerdo a los requisitos psicométricos establecidos, aunque se recomiendan futuros estudios que evalúen su validez y confiabilidad en otros programas de pregrado.The present study examines the factorial structure and reliability of the academic satisfaction questionnaire (CSA) in a sample of 563 medical students, between 19 and 29 years (average of 20.42); from four Chilean universities. Once translated into Spanish explored the validity of the items content was evaluated through experts opinions. The factorial structure of the scale was analyzed through an exploratory factor analysis using the Principal Axis Analysis method (AEP).The preliminary results of the reliability and validity of the instrument have shown that a factor structure is viable and appropriate according to the established psychometric requirements, although future studies to evaluate its validity and reliability in other undergraduate programs are recommended.http://www.redalyc.org/articulo.oa?id=45964543200

Derivation of 30 human embryonic stem cell lines—improving the quality

We have derived 30 human embryonic stem cell lines from supernumerary blastocysts in our laboratory. During the derivation process, we have studied new and safe method to establish good quality lines. All our human embryonic stem cell lines have been derived using human foreskin fibroblasts as feeder cells. The 26 more recent lines were derived in a medium containing serum replacement instead of fetal calf serum. Mechanical isolation of the inner cell mass using flexible metal needles was used in deriving the 10 latest lines. The lines are karyotypically normal, but culture adaptation in two lines has been observed. Our human embryonic stem cell lines are banked, and they are available for researchers

Characterization of Stem-Like Cells in Mucoepidermoid Tracheal Paediatric Tumor

Stem cells contribute to regeneration of tissues and organs. Cells with stem cell-like properties have been identified in tumors from a variety of origins, but to our knowledge there are yet no reports on tumor-related stem cells in the human upper respiratory tract. In the present study, we show that a tracheal mucoepidermoid tumor biopsy obtained from a 6 year-old patient contained a subpopulation of cells with morphology, clonogenicity and surface markers that overlapped with bone marrow mesenchymal stromal cells (BM-MSCs). These cells, designated as MEi (mesenchymal stem cell-like mucoepidermoid tumor) cells, could be differentiated towards mesenchymal lineages both with and without induction, and formed spheroids in vitro. The MEi cells shared several multipotent characteristics with BM-MSCs. However, they displayed differences to BM-MSCs in growth kinectics and gene expression profiles relating to cancer pathways and tube development. Despite this, the MEi cells did not possess in vivo tumor-initiating capacity, as proven by the absence of growth in situ after localized injection in immunocompromised mice. Our results provide an initial characterization of benign tracheal cancer-derived niche cells. We believe that this report could be of importance to further understand tracheal cancer initiation and progression as well as therapeutic development

Consecuencias del estrés calórico sobre la reproducción del ganado vacuno

Heat stress represents one of the major environmental factors that adversely affect the reproductive performance of cattle. In this paper the behavioral adjustments, physical mechanisms and physiological responses to heat loss are described; bos indicus adaptive advantages with respect to bos Taurus, pathophysiology of heat stress and heat stress effects in animal reproduction, both the male and the female.El estrés calórico representa unos de los principales factores del medio ambiente que repercuten negativamente en el desempeño reproductivo del ganado vacuno. En este trabajo se describen los ajustes conductuales, mecanismos físicos y respuestas fisiológicas para la pérdida calórica; ventajas adaptativas del bos indicus con respecto al bos Taurus, fisiopatología del estrés calórico y repercusiones del estrés calórico en la reproducción animal, tanto en el macho como en la hembra

SISTEMA DE EXTRACCION DE LOS COEFICIENTES MAS OPTIMOS PARA UN MODELO NO LINEAL DE UN RF-PA (EXTRACTION SYSTEM OF THE MOST OPTIMAL COEFFICIENTS FOR A RF-PA NON-LINEAR MODEL)

ResumenEn este trabajo se desarrolla un sistema para el modelado de comportamiento de amplificadores de potencia a partir de la extracción de coeficientes basado en los kernels pares, impares y todos de un modelo polinomial con memoria, el sistema toma en cuenta los órdenes de no linealidad y nivel de memoria de corto término del dispositivo. Se implementó en una tarjeta FPGA Cyclone V para un proceso de modelado no lineal basado en banda simple previo a un proceso de predistorsión digital. Además, se desarrolló una interfaz gráfica de usuario que automatiza el proceso de extracción de coeficientes y modelado a partir de los kernels óptimos del modelo polinomial con memoria en base a la métrica NMSE como criterio para determinar la precisión del modelo que se desea calcular a partir de juego de datos de entrada-salida de un amplificador de potencia. Lo anterior se realiza una como alternativa viable de modelado para una etapa posterior de predistorsión digital como medio de reducir el efecto no deseado de recrecimiento espectral e invasión de bandas adyacentes. En este caso se presenta la opción óptima de modelado para un RF-PA de 10 W, donde la mejor precisión obtenida es de -53.48 dB NMSE superando sistemas de modelado reportados en el estado del arte.Palabras Claves: FPGA, Kernels, modelo polinomial con memoria, modelado no lineal, RF-PA. AbstractIn this work a system is developed for the behavior modeling of power amplifiers from the extraction of coefficients based on the odd, even and all kernels of a polynomial model with memory, the system takes into account the orders of non-linearity and short term memory level of the device. It was implemented on a Cyclone V FPGA card for a non-linear modeling process based on single band prior to a digital predistortion process. In addition, a graphical user interface was developed that automate the process of extraction of coefficients and modeling from the optimal kernels of the polynomial model with memory based on the NMSE metric as a criterion to determine the precision of the model to be calculated at starting from input-output data set of a power amplifier. The above is done as a viable modeling alternative for a further stage of digital predistortion as a means of reducing the unwanted effect of spectral regrowth and invasion of adjacent bands. In this case, the optimal modeling option for a 10 W RF-PA is presented, where the best precision obtained for the model found is -53.48 dB NMSE exceeding modeling systems reported in the state of the art.Keywords: FPGA, Kernels, Memory Polinomial Model, non-linear modelling, RF-PA

Human Pluripotent Stem Cells Differentiated in Fully Defined Medium Generate Hematopoietic CD34+ and CD34− Progenitors with Distinct Characteristics

Differentiation of pluripotent stem cells in vitro provides a powerful means to investigate early developmental fates, including hematopoiesis. In particular, the use of a fully defined medium (FDM) would avoid biases induced by unidentified factors contained in serum, and would also allow key molecular mediators involved in such a process to be identified. Our goal was to induce in vitro, the differentiation of human embryonic stem cells (ESC) and induced pluripotent stem cells (iPSC) into morphologically and phenotypically mature leukocytes and erythrocytes, in the complete absence of serum and feeder cells

β-Amyloid 1-42 Oligomers Impair Function of Human Embryonic Stem Cell-Derived Forebrain Cholinergic Neurons

Cognitive impairment in Alzheimer's disease (AD) patients is associated with a decline in the levels of growth factors, impairment of axonal transport and marked degeneration of basal forebrain cholinergic neurons (BFCNs). Neurogenesis persists in the adult human brain, and the stimulation of regenerative processes in the CNS is an attractive prospect for neuroreplacement therapy in neurodegenerative diseases such as AD. Currently, it is still not clear how the pathophysiological environment in the AD brain affects stem cell biology. Previous studies investigating the effects of the β-amyloid (Aβ) peptide on neurogenesis have been inconclusive, since both neurogenic and neurotoxic effects on progenitor cell populations have been reported. In this study, we treated pluripotent human embryonic stem (hES) cells with nerve growth factor (NGF) as well as with fibrillar and oligomeric Aβ1-40 and Aβ1-42 (nM-µM concentrations) and thereafter studied the differentiation in vitro during 28-35 days. The process applied real time quantitative PCR, immunocytochemistry as well as functional studies of intracellular calcium signaling. Treatment with NGF promoted the differentiation into functionally mature BFCNs. In comparison to untreated cells, oligomeric Aβ1–40 increased the number of functional neurons, whereas oligomeric Aβ1–42 suppressed the number of functional neurons. Interestingly, oligomeric Aβ exposure did not influence the number of hES cell-derived neurons compared with untreated cells, while in contrast fibrillar Aβ1–40 and Aβ1–42 induced gliogenesis. These findings indicate that Aβ1–42 oligomers may impair the function of stem cell-derived neurons. We propose that it may be possible for future AD therapies to promote the maturation of functional stem cell-derived neurons by altering the brain microenvironment with trophic support and by targeting different aggregation forms of Aβ