1,512 research outputs found

    The role of generation status and acculturation in the academic achievement of Latina/o college students

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    Abstract only availableOf the 2.9 million Latinas/o students (17% of all high school students in the U.S.) enrolled in secondary education, only 53.2% of these students are expected to graduate from high school, and only 28.2% of these graduates were expected to attend higher education. In hopes of promoting the college success of Latina/o students, researchers have identified factors related to their educational attrition rate in secondary and college education. Although acculturation is widely viewed as a critical factor, research has yielded inconsistent findings about its role in Latinas/o student adjustment. Some studies have suggested that integration is associated with better academic outcomes whereas others support the importance of assimilation. One potential explanation for the conflicting findings regarding optimal acculturation patterns is that most prior research has failed to consider the role of generational status. For instance, one recent study found that identifying as bicultural (having a strong sense of both their ethnic identity and their American identity) was especially important for first and second generation students. In the present study, we investigated the interrelationships among acculturation, generation status, college self-efficacy, and achievement in a sample of 472 (268 female, 204 male) Mexican American college students. We hypothesized that acculturation would interact with generation status to determine student outcomes. Specifically, we expected strong Mexican and Anglo Orientation to be most beneficial in determining GPA for first generation students. Using hierarchical linear regression we found evidence of an interaction between generation status and Mexican Orientation but not Anglo Orientation. The findings help expand the limited research on the impact of generational status on college achievement in Mexican American students. Additionally, the discussion will focus on implications for evolving theories intended to explain the academic achievement and attrition among Latino/a students.MU Undergraduate Research Scholars Progra

    Creativity, pedagogical, and educational innovation: analysis of the perception of a group of Chilean teachers

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    Este estudio se circunscribe al ámbito de la educación, la didáctica y la metodología en el trabajo de aula. Se analizan los resultados de una investigación con enfoque cuantitativo, que tuvo por objetivo identificar la percepción y experiencias acerca de la creatividad, innovación pedagógica y educativa -estas dos últimas nociones no siempre claras y distinguibles en la teoría y los estudios empíricos- en un grupo de docentes que recién inicia su proceso de formación en un programa de postgrado de Magíster en Didáctica, dictado por la Escuela de Educación del Campus Los Ángeles de la Universidad de Concepción, de la provincia y región de Biobío, Chile. La investigación tuvo un alcance descriptivo y como principal técnica de recolección de datos se utilizó un cuestionario de opinión con preguntas abiertas. Los principales hallazgos señalan que el profesorado en general y en un porcentaje mayoritario valora la creatividad, entiende el concepto de innovación pedagógica, pero tiene dificultades para identificar la diferencia entre esta última y la innovación educativa debido a su amplitud conceptual. Además, los resultados señalan que si bien el profesorado cree que la innovación es necesaria y tiene buena predisposición a ella en el ámbito de su labor pedagógica-docente, no siempre se generan las condiciones favorables para su implementación en los establecimientos educativos.This study is circumscribed to the scope of education, didactics, and classroom methodology. The results of an investigation with a quantitative approach will be analyzed, whose aim was to identify the perception and experiences related to creativity, as well as to pedagogical and educational innovation - the two latter concepts not always clear and distinguishable in theory and empirical studies. The research was done in a group of teachers who were just beginning their training process in a Graduate Degree in Didactics, taught in the School of Education at the Los Angeles Campus of the Universidad de Concepción, in the region of Biobío, Chile. The investigation had a descriptive approach and the main method for data collection was an opinion questionnaire with open questions. The main findings show that teachers in general and in a high percentage appreciate creativity, understand the concept of pedagogical innovation, but have difficulties to identify the difference between the latter and educational innovation due to its conceptual breadth. Furthermore, the results show that while teachers believe that innovation is necessary and that they are willing to do it in their pedagogical teaching activity, favorable conditions to implement it in schools are not always generated

    Soliton dynamics in finite nonlocal media with cylindrical symmetry

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    The effect of finite boundaries in the propagation of spatial nonlocal solitons in media with cylindrical symmetry is analyzed. Using Ehrenfest's theorem together with the Green's function of the nonlinear refractive index equation, we derive an analytical expression for the force exerted on the soliton by the boundaries, verifying its validity by full numerical propagation. We show that the dynamics of the soliton are determined not only by the degree of nonlocality, but also by the boundary conditions for the refractive index. In particular, we report that a supercritical pitchfork bifurcation appears when the boundary condition exceed a certain threshold value

    Comparative Genomics Analysis of a New Exiguobacterium Strain from Salar de Huasco Reveals a Repertoire of Stress-Related Genes and Arsenic Resistance

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    Indexación: Web of Science; Scopus.The Atacama Desert hosts diverse ecosystems including salt flats and shallow Andean lakes. Several heavy metals are found in the Atacama Desert, and microorganisms growing in this environment show varying levels of resistance/tolerance to copper, tellurium, and arsenic, among others. Herein, we report the genome sequence and comparative genomic analysis of a new Exiguobacterium strain, sp. SH31, isolated from an altiplanic shallow athalassohaline lake. Exiguobacterium sp. SH31 belongs to the phylogenetic Group II and its closest relative is Exiguobacterium sp. S17, isolated from the Argentinian Altiplano (95% average nucleotide identity). Strain SH31 encodes a wide repertoire of proteins required for cadmium, copper, mercury, tellurium, chromium, and arsenic resistance. Of the 34 Exiguobacterium genomes that were inspected, only isolates SH31 and S17 encode the arsenic efflux pump Acr3. Strain SH31 was able to grow in up to 10 mM arsenite and 100 mM arsenate, indicating that it is arsenic resistant. Further, expression of the ars operon and acr3 was strongly induced in response to both toxics, suggesting that the arsenic efflux pump Acr3 mediates arsenic resistance in Exiguobacterium sp. SH31.http://journal.frontiersin.org/article/10.3389/fmicb.2017.00456/ful

    DASH Adaptation Algorithm Based on Adaptive Forgetting Factor Estimation

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    The wide adoption of multimedia service capable mobile devices, the availability of better networks with higher bandwidths, and the availability of platforms offering digital content has led to an increasing popularity of multimedia streaming services. However, multimedia streaming services can be subject to different factors that affect the quality perceived by the users, such as service interruptions or quality oscillations due to changing network conditions, particularly in mobile networks. Dynamic Adaptive Streaming over HTTP (DASH), leverages the use of content-distribution networks and the capabilities of the multimedia devices to allow multimedia players to dynamically adapt the quality of the media streaming to the available bandwidth and the device characteristics. While many elements of DASH are standardized, the algorithms providing the dynamic adaptation of the streaming are not. The adaptation is often based on the estimation of the throughput or a buffer control mechanism. In this paper, we present a new throughput estimation adaptation algorithm based on a statistical method named Adaptive Forgetting Factor (AFF). Using this method, the adaptation logic is able to react appropriately to the different conditions of different types of networks. A set of experiments with different traffic profiles show that the proposed algorithm improves video quality performance in both wired and wireless environments.Comment: 11 page

    In situ enzymatic generation of Au/Pt nanoparticles as an analytical photometric system: proof of concept determination of tyramine

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    In situ enzymatic generation of bimetallic nanoparticles, mainly Au/Pt, overcomes the drawbacks (continuous absorbance drift, modest LOQ, and long-time reaction) observed when AuNP alone are produced. In this study, Au/Pt nanoparticles have been characterized by EDS, XPS, and HRTEM images using the enzymatic determination of tyramine with tyramine oxidase (TAO) as a model. Under experimental conditions, the Au/Pt NPs show an absorption maximum at 580 nm which can be related to the concentration of tyramine in the range 1.0 × 10-6M to 2.5 × 10-4M with a RSD of 3.4% (n = 5, using 5 × 10-6M tyramine). The Au/Pt system enables low LOQ (1.0 × 10−6 M), high reduction of the absorbance drift, and a significant shortening of the reaction time (i.e., from 30 to 2 min for a [tyramine] = 1 × 10−4M); additionally, a better selectivity is also obtained. The method has been applied to tyramine determination in cured cheese and no significant differences were obtained compared to a reference method (HRP:TMB). The effect of Pt(II) seems to involve the previous reduction of Au(III) to Au(I) and NP generation from this oxidation state. Finally, a three-step (nucleation-growth-aggregation) kinetic model for the generation of NPs is proposed; this has enabled us to obtain a mathematical equation which explains the experimentally observed variation of the absorbance with time

    Influence of the level of neurological deficit on the efficacy of cell therapy in a model of severe traumatic brain injury

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    Objetivo: Determinar si el nivel de déficit neurológico influye en la eficacia de la terapia celular con células madre mesenquimales (CMM) de la médula ósea en un modelo experimental crónico de lesión cerebral traumática. Material y métodos: Se sometió a ratas Wistar adultas a un modelo de lesión cerebral traumática. Dos meses después, se clasificaron en función de su nivel de déficit neurológico mediante dos tests funcionales: Escala de valoración sensitivo-motora y Tiempo de permanencia en la zona interior (Video-Tracking-Box test, VTB test). Se inyectó suero salino solo o CMM en suero salino en el tejido cerebral dañado de los animales que obtuvieron la clasificación neurológica de lesión moderada o grave según el nivel permanente de su déficit funcional. Todos los animales se evaluaron durante los dos meses siguientes para determinar la posible eficacia de la administración de las CMM. Al finalizar el estudio, los animales se eutanasiaron y se estudiaron sus cerebros. Resultados: Se constata una recuperación funcional significativa en los animales con lesión moderada que recibieron las CMM, pero no en los animales con lesión grave cuando se compara con los controles. Conclusiones: Las conclusiones obtenidas sugieren que la gravedad de la lesión neurológica puede influir en la potencial eficacia de la terapia celular cuando es aplicada en una lesión cerebral traumática crónicaObjective: To study if the level of neurological deficit influences the efficacy of cell therapy with bone marrow stromal cells (BMSC), in an experimental model of chronic traumatic brain injury (TBI). Material and methods: Adult Wistar rats were subjected to a model of traumatic brain injury. Two months later they were classified according to their level of neurological deficit. For that, two functional tests: Scale of sensory- motor assessment and time spent in the inner zone in the Video-Tracking-Box test, were used. Saline alone or BMSC in saline was injected into the damaged brain tissue of animals suffering a permanent level of functional deficit classified as moderate or severe. All experimental groups were evaluated during the next two months to determine the potential effectiveness of the intracerebral administration of BMSC. At the end of the study animals were euthanized and their brains were studied. Results: The results show a significant functional recovery in animals with moderate injury who received BMSC, but there was no significant recovery in animals with severe traumatic brain injury when compared with controls. Conclusion: The severity of neurologic injury may influence the potential efficacy of cell therapy applied to chronic TBIEsta investigación ha sido financiada por FUNDACIÓN MAPFR

    Endogenous neurogenesis after traumatic brain injury and its modulation by cell therapy

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    Objetivo: Estudiar la neurogénesis inducida por una lesión traumática cerebral y su modulación mediante terapia celular. Material y métodos: Se realizó un modelo de lesión cerebral traumática en ratas Wistar adultas causando un daño cerebral grave. Transcurridos dos meses de la lesión, se administraron intralesionalmente células madre estromales (CME) alogénicas obtenidas de médula ósea, o suero fisiológico. Se estudió histológicamente la zona subventricular (ZSV) de cada animal al objeto de valorar la neurogénesis endógena espontánea tras la lesión y su posible modificación por la administración intracerebral de CME. Igualmente, se valoró la modificación de los déficit funcionales tras el tratamiento. Resultados: Se detectó un aumento en la neurogénesis endógena en el grupo tratado con CME respecto del control. Este hallazgo estuvo asociado a una progresiva mejoría en la respuesta motora y sensorial en el grupo de animales que recibieron CME comparado con el grupo de animales control. Conclusiones: La eficacia de la terapia celular para revertir los déficit funcionales secundarios a una lesión traumática cerebral parece correlacionarse con un incremento de la neurogénesis endógena a nivel de la SVZObjective: To study the neurogenesis induced by traumatic brain injury and its modulation by cell therapy. Material and methods: We performed a model of traumatic brain injury in adult Wistar rats, causing severe brain damage. After 2 months of injury, allogeneic bone marrow stromal cells (BMSC) or saline were administered intralesionally. We studied histologically the subventricular zone (SVZ) of each animal, in order to assess endogenous neurogenesis after traumatic brain injury and its possible modulation by intracerebral administration of BMSC. Furthermore, we studied the modification of neurological deficits after BMSC administration. Results: We detected a rise in endogenous neurogenesis in the group treated with BMSC with respect to the control. This finding was associated with a progressive improvement in motor and sensory response in the group of animals that received BMSC compared with control animals. Conclusion: The efficacy of cell therapy using BMSC appears to correlate with an increase of endogenous neurogenesis at SVZ levelEsta investigación ha sido financiada por FUNDACIÓN MAPFR

    Aplicación de la estadística en temáticas de administración de empresas

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    El presente artículo da cuenta de una experiencia de aula desarrollada en el Instituto de Educación Continua de la Universidad de Los Lagos de Osorno – Chile con alumnos y alumnas del primer año de la carrera Técnico Universitario en Administración de Empresas, quienes en el módulo de Estadística desarrollaron investigaciones en sus lugares de trabajo sobre temas propios de su profesión. Los estudiantes formaron equipos de trabajo y eligieron problemáticas relacionadas a sus carreras, luego aplicaron cuestionarios para recolectar información, presentaron los datos recopilados en tablas y gráficos de los cuales obtuvieron estadígrafos que permitieron establecer conclusiones. Para la descripción y análisis de los resultados, cada equipo realizó un informe escrito sobre la investigación. Como resultado de la experiencia se logró que los estudiantes se introdujeran en una problemática propia de su área laboral, investigaran y recopilaran información sobre el tema y pudieran visualizar a la estadística como una disciplina potencialmente útil para su formación profesional y futura vida laboral
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