428 research outputs found
Las dificultades para la educación integradora desde la perspectiva de futuros maestros de inglés
El presente artÃculo presenta y analiza los hallazgos de un estudio de naturaleza cualitativa sobre las percepciones que expresan futuros maestros especialistas de inglés en el transcurso de las Prácticas de Enseñanza sobre la integración y la atención a las necesidades educativas especiales en el aula ordinaria. El análisis de los datos textuales aportados por los informantes, además de revelar las ideas que éstos sostienen en torno a la integración, evidencia una frecuente ausencia de experiencias de enseñanza auténticamente integradoras durante ese perÃodo crÃtico de formación profesional
Multimetallic (de)hydrogenation catalysed processes
The use of different metals working together in a
synergistic way, allows synthetic transformations that are not
achievable by other means. The metal cooperation becomes
important in catalytic processes for the synthesis of sophisticated
molecules or difficult transformations. A rationale design of
multimetallic catalysed processes entails metal complexes and
reaction conditions being compatible, which in general is not
straightforward. A key feature for success found in all systems
dealing with multimetallic processes is catalyst stability. The use of
robust metal complexes increases the probability of success in the
search of tandem catalytic processes. This microreview is based on
the recent and most important findings of multimetallic catalysed
processes that involved (de)hydrogenation reactions. The field
constitutes a research area that is full of potential and can be
foreseen that relevant applications will be described in the near
future.MINECO (CTQ2015-69153-C2-2-R), Generalitat Valenciana (AICO/2015/039),
Universitat Jaume I (P1.1B2015-09
Suministro de feedback a ensayos sobre diarios en un programa de prácticas de enseñanza: propuesta de una modalidad apoyada en TICs y estudio de percepciones del alumnado
Una de las estrategias recomendadas como favorecedoras de procesos de reflexión sobre la enseñanza en programas de formación inicial de profesorado es el suministro de comentarios a las tareas de escritura reflexiva que en ellos se proponen habitualmente. Partiendo de un modelo reflexivo de formación, este artÃculo presenta una modalidad de suministro de feedback que precisa del concurso de las TICs como medios de agilizar dicho suministro y facilitar un diálogo escrito entre formador y estudiante para maestro; además, el artÃculo presenta y discute los hallazgos de un estudio en torno a las percepciones del alumnado sobre el medio y el procedimiento de aporte de feedback a través de la modalidad descrita .One of the strategies which are frequently mentioned as facilitative of reflection on teaching matters in
initial teacher education is the instructor's provision of feedback related to reflective assignments. Starting
from a reflective model of teacher education, this article discusses a modality of feedback provision based
on ICT as a medium to facilitate a 'written dialogue' between the prospective teacher and the educator;
besides, the article analyses the findings of a descriptive study aimed at investigating students perceptions
about the medium and the modality of feedback provision
Estudio de la eficacia de tres pelÃculas flexibles para la conservación de alimentos perecederos
Tesis (MaestrÃa en Ciencias con Especialidad en MicrobiologÃa) UANLUANLhttp://www.uanl.mx
LOS CONTAMINANTES EN EL CULTIVO E INDUSTRIALIZACION DE LA CAÑA DE AZÚCAR
Con el proceso de desincorporación de Fertimex en 1985, el consumo de fertilizantes disminuyó un poco. Sin embargo, en la presente década, el uso de fertilizantes en México se ha incrementado. Considerando que en 2006, el consumo fue de 4.3 millones de toneladas, para el 2007, la cifra aumentó a 4.7 millone
Evaluación del nivel de estrés en leoncillos (Callithrix pygmeea) mediante la medición de cortisol en heces
The pigmy marmoset or leoncillo (Callithrix pygmaea) is the smallest known platyrrhine primate species. It lives only in gallery forests in the Upper Amazon basin of Colombia, Ecuador, Peru and Brazil. Although, all the species of primates in Ecuador are threatened by human activities, pigmy marmoset is the most vulnerable, due to its limited size and the uniqueness of its diet and habitat. Considering the area of distribution, the fragmentation of the forests, and the illegal traffic of pets, the populations of C. pygmaea have been seriously affected. As a result, this primate, has been included in the list of vulnerable species in Ecuador. The objective of this research project was to determine the levels of stress to which 3 populations of leoncillos from the eastern zone of Ecuador are subjected due to the previously mentioned factors. As an indicator of the level of stress, cortisol content in feces was used. A total of 92 samples were analyzed corresponding to the populations of Puyo, Tiputini and San Pablo, from which only 52 were included for the statistical analyses. Different levels of stress were determined among the three populations (ANOVA, p=0.00033). The population from Puyo was the one with the highest level of stress in comparison with the populations from Tiputini and San Pablo (Tukey p=0.0043848 and p=0.0006135) respectively. The non-invasive method to determinate the levels of cortisol in the feces samples, seems to be a reliable and safe technique; nevertheless, for a major reliability of the results it would be suitable to enhance the information about the time of collection of the sample, the sex, the age and the previous activities of the individuals.El tità pigmeo o leoncillo (Callithrix pygmaea), es la especie de primates platirrinos más pequeña. Habita en bosques siempre verdes de tierras bajas inundables de la AmazonÃa de Colombia, Ecuador, Perú, Bolivia y Brasil. Aunque todas las especies de primates en el Ecuador están amenazadas por las actividades humanas, ésta es una de las más vulnerables, debido a su tamaño reducido y a la especificidad de su alimentación y hábitat. Considerando su área de distribución y los problemas de fragmentación de los bosques, junto con el tráfico ilegal de mascotas, la población de C. pygmaea se ha visto seriamente afectada, por lo que actualmente ha sido incluida en la lista de especies vulnerables en el Ecuador. El objetivo de esta investigación fue determinar los niveles de estrés a los que están sometidas tres poblaciones de leoncillos del oriente ecuatoriano debido a los factores mencionados anteriormente. Como indicador del nivel de estrés se usó el contenido de cortisol en heces de leoncillos. Se analizaron 92 muestras de las poblaciones del Puyo, Tiputini y San Pablo de las cuales 52 fueron incluidas para los análisis estadÃsticos. Se determinó diferentes niveles de estrés en las tres poblaciones (ANOVA, p=0.00033). La población de Puyo es la que presentó mayor nivel de estrés en comparación con Tiputini y San Pablo (Tukey p=0.0043848 y p=0.0006135) respectivamente. El método no invasivo de determinación de los niveles de cortisol en muestras de heces, parece ser una técnica confiable, sin embargo para mayor confiabilidad de los resultados serÃa conveniente complementar la información respecto de las horas de colección de la muestra, el sexo, la edad del individuo y sus actividades previas
Detection of Listeria monocytogenes in artisanal soft cheeses from different street markets of Ecuador
L. monocytogenes is one of the most important bacteria related with foodborne diseases.
It causes an infectious disease known as listeriosis, which reports a significant impact
on public health due to its high mortality rate (20-30% even with treatment)...L. monocytogenes es una de las bacterias más importantes relacionadas con las
enfermedades transmitidas por los alimentos. Causa una enfermedad infecciosa
conocida como listeriosis, que reporta un impacto significativo en la salud pública
debido a su alta tasa de mortalidad (20-30% incluso con tratamiento)..
Enhancement of gold catalytic activity and stability by immobilization on the surface of graphene
The catalytic performance of gold complexes is evaluated at the molecular level and when supported onto reduced graphene oxide (rGO). Gold complexes of general formula [(NHC)AuX] catalyse the synthesis of indoles via intramolecular hydroamination reaction of alkynes. The catalytic properties of the molecular gold complexes are highly improved when supported onto graphene. Faster reaction rates and higher catalyst stability are observed for the immobilized gold complexes. The use of graphene as support of molecular complexes has a positive benefit in the catalytic gold properties in terms of activity and stabilityThe authors thank the financial support from MINECO (CTQ2015-69153-C2-2-R), Generalitat Valenciana (AICO/2015/039) and Universitat Jaume I (P1.1B2015-09). D. V-E thanks MINECO for a FPU grant (FPU15/03011
Ruthenium molecular complexes immobilized on graphene as active catalysts for the synthesis of carboxylic acids from alcohol dehydrogenation
Ruthenium complexes containing N-heterocyclic carbene ligands functionalized
with different polyaromatic groups (pentafluorophenyl, anthracene, and pyrene) are
immobilized onto the surface of reduced graphene oxide. The hybrid materials composed of
organometallic complexes and graphene are obtained in a single-step process. The hybrid
materials are efficient catalysts for the synthesis of carboxylic acids from the dehydrogenation
of alcohols in aqueous media. The catalytic materials can be recycled up to ten times without
significant loss of activity. The catalytic activity of the pyrene derivative, Pyr-Ru (3) is enhanced
when the ruthenium complex is anchored onto the surface of graphene. The carbonaceous
material limits the degradation of the ruthenium complex resulting in increased activity and
requiring lower catalyst loadings. The catalytic process of the pyrene hybrid material is
heterogeneous in nature due to the strong interaction between the pyrene and graphene. The
catalytic process of the anthracene and pentafluorophenyl hybrid materials is governed by the
so-called ‘boomerang effect’. The ruthenium molecular complex is released from and returned
to the graphene surface during the catalytic reaction. Mechanistic insight has been obtained
experimentally and theoretically. The energy profile suggests that the rate-determining step is the water nucleophilic attack to a coordinated aldehyde complex to form a gem-diolate
complex.The authors thank the financial support from MINECO (CTQ2015-69153-C2-2-R and CTQ2015-
67461-P), Generalitat Valenciana (AICO/2015/039), Universitat Jaume I (P1.1B2015-09) and
Universidad de Zaragoza (UZ2014-CIE-01)
- …