2,803 research outputs found

    Factores que influyen en la reprobación en la educación media superior bajo un modelo por competencias

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    En este trabajo se identificaron algunos factores que influyen en la reprobación estudiantil en el nivel medio superior, trabajando bajo un modelo por competencias, en el área de matemáticas. La investigación se realizó en la Escuela Industrial y Preparatoria Técnica “Pablo Livas” (EIPTPL) perteneciente a la Universidad Autónoma de Nuevo León, analizando la unidad de aprendizaje Matemáticas I, la cual se imparte en el segundo semestre, correspondiente al semestre Enero-Junio 2014. Los factores que se consideraron fueron al docente, las actividades que se realizan, el programa analítico y el propio estudiante. La recopilación de datos se realizó a través de una encuesta, que se aplicó a una muestra representativa de estudiantes inscritos a la unidad de aprendizaje Matemáticas II y que hubiesen reprobado la primera oportunidad de Matemáticas I. Se obtuvieron resultados que nos permiten determinar al docente junto con las actividades como principales factores que afectan a los estudiantes para reprobar Matemáticas I

    El “velo de maya” en la tradición filosófica hindú. Un diálogo comparado con El mundo como voluntad y representación de Schopenhauer

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    En este trabajo de fin de grado se realiza un estudio comparado entre la tradición hindú y el pensamiento de Schopenhauer. El objetivo es analizar el significado filosófico originario de maya o “velo de maya” en las fuentes hindúes y, posteriormente, compararlo con el usado por Schopenhauer en El mundo como voluntad y representación. La primera parte muestra la evolución de maya en la etapa prefilosófica y considerada sagrada, los Vedas, en la época brahmánica y en una de las escuelas clásicas más importantes de este pensamiento oriental, la escuela vedanta. El análisis realizado se basa en el comentario de algunos pasajes, extraídos de los libros sagrados más destacados de cada periodo mencionado; en concreto, los fragmentos proceden del Rig Veda, de las Upanishads y de la Āgamasastrā. En la segunda parte se analiza el concepto filosófico de maya empleado por Schopenhauer en su obra cumbre, haciendo hincapié tanto en el significado otorgado a nivel cognoscitivo, así como en el moral. Por último, se cruzan los significados empleados en la tradición hindú, explicada en la primera parte, con los encontrados en El mundo como voluntad y representación para evaluar sus semejanzas y diferencias. La tesis principal es que el filósofo de Dänzig usa el concepto de maya de forma correcta a nivel general, pero comete imprecisiones y errores cuando relaciona la teoría sobre maya con sus propias tesis, influenciada por Kant, al que critica y matiza, ajustando la sabiduría de los Vedas, el pensamiento brahmánico y el vedanta a su exposición

    Valence band offset of the ZnO/AlN heterojunction determined by X-ray photoemission spectroscopy

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    The valence band offset of ZnO/AlN heterojunctions is determined by high resolution x-ray photoemission spectroscopy. The valence band of ZnO is found to be 0.43±0.17 eV below that of AlN. Together with the resulting conduction band offset of 3.29±0.20 eV, this indicates that a type-II (staggered) band line up exists at the ZnO/AlN heterojunction. Using the III-nitride band offsets and the transitivity rule, the valence band offsets for ZnO/GaN and ZnO/InN heterojunctions are derived as 1.37 and 1.95 eV, respectively, significantly higher than the previously determined values

    Respiratory syncytial virus hospitalization in children in northern Spain

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    Objectives: Understanding respiratory syncytial virus (RSV) morbidity may help to plan health care and future vaccine recommendations. We aim to describe the characteristics and temporal distribution of children diagnosed with RSV admitted in a Spanish hospital. Methods: Descriptive study for which the hospital discharges of children < 5 years of age with RSV infection were analyzed. The information was extracted from the hospital discharge database of a reference pediatric hospital in northern Spain for the 2010-2011 to 2014-2015 RSV seasons. Results: Six hundred and forty-seven hospitalizations of children with RSV infection were analyzed, 94% of which occurred between the second week of November and the last week of March. Most children (72%) were under one year of age and 95% were previously healthy infants. Infants born from October to December had the highest risk of hospitalization in the first year of life. The median length of hospital stay of children with and without comorbidities was six and three days, respectively. 6.5% of the hospitalized cases were admitted to the pediatric intensive care unit; this percentage was higher among children < 2 months (adjusted odds ratio 4.15; 95% confidence interval: 1.37-12.61) or with comorbidities (adjusted odds ratio 4.15; 95% confidence interval: 1.53-11.28). The case lethality was 0.3%. Conclusions: The risk of hospitalizations for RSV is high during the first year of life and increases among infants born in the fall. Being under two months of age and presenting comorbidities are the main risk factors associated to pediatric intensive care unit admission

    Experimental increase in baseline corticosterone level reduces oxidative damage and enhances innate immune response

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    Glucocorticoid (GC) hormones are significant regulators of homeostasis. The physiological effects of GCs critically depend on the time of exposure (short vs. long) as well as on their circulating levels (baseline vs. stress-induced). Previous experiments, in which chronic and high elevation of GC levels was induced, indicate that GCs impair both the activity of the immune system and the oxidative balance. Nonetheless, our knowledge on how mildly elevated GC levels, a situation much more common in nature, might influence homeostasis is limited. Therefore, we studied whether an increase in GC level within the baseline range suppresses or enhances condition (body mass, hematocrit and coccidian infestation) and physiological state (humoral innate immune system activity and oxidative balance). We implanted captive house sparrows Passer domesticus with either 60 days release corticosterone (CORT) or control pellets. CORT-treated birds had elevated baseline CORT levels one week after the implantation, but following this CORT returned to its pre-treatment level and the experimental groups had similar CORT levels one and two months following the implantation. The mass of tail feathers grown during the initial phase of treatment was smaller in treated than in control birds. CORT implantation had a transient negative effect on body mass and hematocrit, but both of these traits resumed the pre-treatment values by one month post-treatment. CORT treatment lowered oxidative damage to lipids (malondialdehyde) and enhanced constitutive innate immunity at one week and one month post-implantation. Our findings suggest that a relatively short-term (i.e. few days) elevation of baseline CORT might have a positive and stimulatory effect on animal physiology

    Effect of temperature on RNA silencing of a negative-stranded RNA plant virus: Citrus psorosis virus

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    Citrus psorosis virus (CPsV), genus Ophiovirus, causes a bark scaling disease of citrus. CPsV virions are kinked filaments with three negative-stranded RNA molecules (vRNA) and a 48 kDa coat protein. The effect of temperature on symptom expression, virus accumulation and RNA silencing was examined in sweet orange seedlings (Citrus sinensis) graft-inoculated with three different CPsV isolates and grown in a glasshouse at 26/18°C or 32/26°C (day/night). Most plants kept in the cooler glasshouse showed a shock reaction in the first flush with shoot necrosis, and then moderate to intense chlorotic flecking and spotting in young leaves, whereas plants incubated at 32/26°C did not exhibit shoot necrosis, and young leaf symptoms were milder. Virus titre estimated by ELISA and by northern and dot blot hybridization paralleled symptom intensity, with significantly higher virus accumulation in plants incubated at 26/18°C. The amount of CPsV-derived small RNAs (CPsV-sRNAs) slightly increased at 32/26°C, with the ratio of CPsV-sRNA/vRNA being higher at 32/26°C than at 26/18°C. These results suggest that (i) CPsV infection induces RNA silencing in citrus plants, (ii) symptom intensity is associated with virus accumulation, and (iii) temperature increase enhances the RNA silencing response of citrus plants and decreases virus accumulation.Facultad de Ciencias Exacta

    TOMATO AGAMOUS1 and ARLEQUIN/TOMATO AGAMOUS-LIKE1 MADS-box genes have redundant and divergent functions required for tomato reproductive development

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    [EN] Within the tomato MADS-box gene family, TOMATO AGAMOUS1 (TAG1) and ARLEQUIN/TOMATO AGAMOUS LIKE1 (hereafter referred to as TAGL1) are, respectively, members of the euAG and PLE lineages of the AGAMOUS clade. They perform crucial functions specifying stamen and carpel development in the flower and controlling late fruit development. To gain insight into the roles of TAG1 and TAGL1 genes and to better understand their functional redundancy and diversification, we characterized single and double RNAi silencing lines of these genes and analyzed expression profiles of regulatory genes involved in reproductive development. Double RNAi lines did show cell abnormalities in stamens and carpels and produced extremely small fruit-like organs displaying some sepaloid features. Expression analyses indicated that TAG1 and TAGL1 act together to repress fourth whorl sepal development, most likely through the MACROCALYX gene. Results also proved that TAG1 and TAGL1 have diversified their functions in fruit development: while TAG1 controls placenta and seed formation, TAGL1 participates in cuticle development and lignin biosynthesis inhibition. It is noteworthy that both TAG1 and double RNAi plants lacked seed development due to abnormalities in pollen formation. This seedless phenotype was not associated with changes in the expression of B-class stamen identity genes Tomato MADS-box 6 and Tomato PISTILLATA observed in silencing lines, suggesting that other regulatory factors should participate in pollen formation. Taken together, results here reported support the idea that both redundant and divergent functions of TAG1 and TAGL1 genes are needed to control tomato reproductive development.This work was supported by the Spanish Ministry of Economy and Competitiveness (Grant Numbers AGL2012-40150-C03-01, AGL2012-40150-C03-02 and AGL2015-64991-C3-1-R); and the European Commission through the JAE-Doc Program of the Spanish National Research Council (CSIC) (Grant Number AGL2012-40150-C03-01 to B.P.).Giménez Caminero, ME.; Castañeda, L.; Pineda Chaza, BJ.; Pan, IL.; Moreno Ferrero, V.; Angosto, T.; Lozano, R. (2016). TOMATO AGAMOUS1 and ARLEQUIN/TOMATO AGAMOUS-LIKE1 MADS-box genes have redundant and divergent functions required for tomato reproductive development. Plant Molecular Biology. 91(4-5):513-531. https://doi.org/10.1007/s11103-016-0485-4S513531914-

    Effect of temperature on RNA silencing of a negative-stranded RNA plant virus: Citrus psorosis virus

    Get PDF
    Citrus psorosis virus (CPsV), genus Ophiovirus, causes a bark scaling disease of citrus. CPsV virions are kinked filaments with three negative-stranded RNA molecules (vRNA) and a 48 kDa coat protein. The effect of temperature on symptom expression, virus accumulation and RNA silencing was examined in sweet orange seedlings (Citrus sinensis) graft-inoculated with three different CPsV isolates and grown in a glasshouse at 26/18°C or 32/26°C (day/night). Most plants kept in the cooler glasshouse showed a shock reaction in the first flush with shoot necrosis, and then moderate to intense chlorotic flecking and spotting in young leaves, whereas plants incubated at 32/26°C did not exhibit shoot necrosis, and young leaf symptoms were milder. Virus titre estimated by ELISA and by northern and dot blot hybridization paralleled symptom intensity, with significantly higher virus accumulation in plants incubated at 26/18°C. The amount of CPsV-derived small RNAs (CPsV-sRNAs) slightly increased at 32/26°C, with the ratio of CPsV-sRNA/vRNA being higher at 32/26°C than at 26/18°C. These results suggest that (i) CPsV infection induces RNA silencing in citrus plants, (ii) symptom intensity is associated with virus accumulation, and (iii) temperature increase enhances the RNA silencing response of citrus plants and decreases virus accumulation.Facultad de Ciencias Exacta

    Prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated sewage sludges

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    Treated sludge from wastewater treatment plants (WWTPs) is commonly used in agriculture as fertilizers and to amend soils. The most significant health hazard for sewage sludge relates to the wide range of pathogenic microorganisms such as protozoa parasites.The objective of this study was to collect quantitative data on Cryptosporidium oocysts and Giardia cysts in the treated sludge in wastewater treatment facilities in Spain. Sludge from five WWTPs with different stabilization processes has been analysed for the presence of Cryptosporidium and Giardia in the raw sludge and after the sludge treatment. A composting plant (CP) has also been assessed. After a sedimentation step, sludge samples were processed and (oo)cysts were isolated by immunomagnetic separation (IMS) and detected by immunofluorescence assay (IFA). Results obtained in this study showed that Cryptosporidium oocysts and Giardia cysts were present in 26 of the 30 samples (86.6%) of raw sludge samples. In treated sludge samples, (oo)cysts have been observed in all WWTP's analysed (25 samples) with different stabilization treatment (83.3%). Only in samples from the CP no (oo)cysts were detected. This study provides evidence that (oo)cysts are present in sewage sludge-end products from wastewater treatment processes with the negative consequences for public health.We appreciate the financial support provided by Entidad Publica Saneamiento Aguas (EPSAR).Amoros Muñoz, I.; Moreno Trigos, MY.; Reyes-Sosa, MB.; Moreno-Mesonero, L.; Alonso Molina, JL. (2016). Prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated sewage sludges. Environmental Technology. 37(22):2898-2904. doi:10.1080/09593330.2016.1168486S28982904372
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