974 resultados para Boîte homéo


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El artículo forma parte de un monográfico de la revista dedicado a la iconografía en la enseñanza de la historia. - Todos los artículos de este monográfico han sido elaborados por el equipo del Departamento de Didáctica de las Ciencias Sociales de la Universidad de Valladolid

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El art??culo forma parte de un monogr??fico dedicado a los yacimientos arqueol??gicos de la Sierra de Atapuerca

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Relacionar determinados factores cognitivos, perceptivos y psicomotores con la capacidad de escribir correcta o incorrectamente. 153 sujetos: 76 del grupo experimental y 77 del grupo de control, elegidos por maestros de 11 centros, según el criterio de identificar a aquellos que presentaran escritura ilegible o evidentes errores en la ejecución de letras sin que tengan diagnosticada ninguna deficiencia mental física o sensorial. Una vez conocidos los sujetos de la prueba, se han administrado las pruebas en sala distinta al aula de clase en dos sesiones y con la sóla presencia del examinador. Para la recogida de los datos familiares se elaboró un pequeño cuestionario cerrado donde los padres y tutores marcaban las respuestas a las preguntas. Se envió a las familias a través de los hijos. Los datos de las pruebas se han registrado en unos protocolos de recogida de información y se han trasladado posteriormente a una base de datos para su tratamiento estadístico realizado con el programa SPSS 9.0 para windows. Test de análisis de lectoescritura, TALE, de Toro y Cervera, 1984. Test Guestáltico Visomotor de Bender (1957, Koppittz, 1995). Test de Matrices Progresivas de Raven, Escala Color (Raven, Court y Raven, 2001). Test de Goodenough (1971, Harris 1989). Balance Psicomotor de Picq y Vayer, 1977. Test de Ozeretski (revisado por Guilman, 1948). Prueba de bote de balón de elaboración propia. Dominancia lateral espontánea, de elaboración propia y Prueba de punteado de Mira Stambak, 1976. Estudio observacional analítico de tipo transversal caso-control, apareado. Se ha elegido un diseño transversal de comparación de grupos homogéneos (experimental y de control), neutralizando una serie de variables que pudieran afectar a la fiabilidad de los resultados (edad, género y nivel sociocultural). Se comprueba que los niños que escriben con mala letra presentan niveles inferiores de desarrollo cognitivo, afectivo y motor que los que escriben correctamente aunque no presentan niveles inferiores de desarrollo del lenguaje. Además, presentan menor destreza a nivel motor fino (no grueso) e inferior nivel de desarrolo perceptivo-motor. Entre los niños que escriben con mala letra hay más proporción de zurdos y de varores.

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Se lleva a cabo una indagación de las emociones y se destaca la importancia que tienen en la educación. Se acepta un enfoque naturalista de explicación y se enfatiza el papel fundamental del cuerpo y del cerebro para la generación de las emociones y su fundamento filogenético. Se analiza la relación entre emoción y sentimiento. A continuación, se introduce el papel de la cultura; la intencionalidad y las comunidades cognitivas en el desarrollo del homo sapiens; su sociabilidad; su educación y su evolución misma. Por último, se apela a un enfoque complementario y naturalista para explicar y entender al ser humano.

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Resumen basado en el de la publicaci??n

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Resumen tomado de la publicaci??n.

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Aquesta Tesi Doctoral està dividida en diferents capítols tots ells basats en aplicacions de macrocicles nitrogenats triolefínics de 15 membres i dels seus complexos amb metalls de transició. En primer lloc es descriu l'aplicació d'un complex macrocíclic ferrocenílic de Pd0 com a catalitzador en reaccions de Mizoroki-Heck i Suzuki emprant sals de diazoni com a agents arilants. Aquest catalitzador va proporcionar bons rendiments de productes i va poder ser recuperat i reutilitzat, essent el primer sistema catalític reciclable descrit en la reacció de Mizoroki-Heck amb sals de diazoni. La metodologia es va estendre de forma efectiva a alcohols al·lílics, però en no ser possible recuperar el catalitzador macrocíclic, es va emprar Pd(dba)2. Posteriorment es van preparar estructures macromoleculars mitjançant la introducció de diferents unitats macrocícliques sobre un espaiador. La complexació d'aquestes estructures va permetre preparar complexos tant homo (Pd0) com heterometàl·lics (Pd0, Pt0) amb bons rendiments. Els complexos homometàl·lics van resultar ser bons catalitzadors en reaccions de Suzuki i fàcilment recuperables per simple filtració. En una última part, es van preparar nous macrocicles triolefínics contenint d'un a tres grups amino lliures en l'estructura mitjançant la utilització del grup protector (2-trimetilsilil)etansulfonil (SES). Aquesta modificació estructural va permetre ampliar la capacitat coordinant dels macrocicles a altres metalls de transició, com el PdII, possibilitant noves aplicacions. Concretament es va aplicar el lligand contenint un sol grup amino lliure al reconeixement, transport i preconcentració de PdII i PtIV continguts en dissolucions aquoses.

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The [2+2+2] cycloaddition reaction involves the formation of three carbon-carbon bonds in one single step using alkynes, alkenes, nitriles, carbonyls and other unsaturated reagents as reactants. This is one of the most elegant methods for the construction of polycyclic aromatic compounds and heteroaromatic, which have important academic and industrial uses. The thesis is divided into ten chapters including six related publications. The first study based on the Wilkinson’s catalyst, RhCl(PPh3)3, compares the reaction mechanism of the [2+2+2] cycloaddition process of acetylene with the cycloaddition obtained for the model of the complex, RhCl(PH3)3. In an attempt to reduce computational costs in DFT studies, this research project aimed to substitute PPh3 ligands for PH3, despite the electronic and steric effects produced by PPh3 ligands being significantly different to those created by PH3 ones. In this first study, detailed theoretical calculations were performed to determine the reaction mechanism of the two complexes. Despite some differences being detected, it was found that modelling PPh3 by PH3 in the catalyst helps to reduce the computational cost significantly while at the same time providing qualitatively acceptable results. Taking into account the results obtained in this earlier study, the model of the Wilkinson’s catalyst, RhCl(PH3)3, was applied to study different [2+2+2] cycloaddition reactions with unsaturated systems conducted in the laboratory. Our research group found that in the case of totally closed systems, specifically 15- and 25-membered azamacrocycles can afford benzenic compounds, except in the case of 20-membered azamacrocycle (20-MAA) which was inactive with the Wilkinson’s catalyst. In this study, theoretical calculations allowed to determine the origin of the different reactivity of the 20-MAA, where it was found that the activation barrier of the oxidative addition of two alkynes is higher than those obtained for the 15- and 25-membered macrocycles. This barrier was attributed primarily to the interaction energy, which corresponds to the energy that is released when the two deformed reagents interact in the transition state. The main factor that helped to provide an explanation to the different reactivity observed was that the 20-MAA had a more stable and delocalized HOMO orbital in the oxidative addition step. Moreover, we observed that the formation of a strained ten-membered ring during the cycloaddition of 20-MAA presents significant steric hindrance. Furthermore, in Chapter 5, an electrochemical study is presented in collaboration with Prof. Anny Jutand from Paris. This work allowed studying the main steps of the catalytic cycle of the [2+2+2] cycloaddition reaction between diynes with a monoalkyne. First kinetic data were obtained of the [2+2+2] cycloaddition process catalyzed by the Wilkinson’s catalyst, where it was observed that the rate-determining step of the reaction can change depending on the structure of the starting reagents. In the case of the [2+2+2] cycloaddition reaction involving two alkynes and one alkene in the same molecule (enediynes), it is well known that the oxidative coupling may occur between two alkynes giving the corresponding metallacyclopentadiene, or between one alkyne and the alkene affording the metallacyclopentene complex. Wilkinson’s model was used in DFT calculations to analyze the different factors that may influence in the reaction mechanism. Here it was observed that the cyclic enediynes always prefer the oxidative coupling between two alkynes moieties, while the acyclic cases have different preferences depending on the linker and the substituents used in the alkynes. Moreover, the Wilkinson’s model was used to explain the experimental results achieved in Chapter 7 where the [2+2+2] cycloaddition reaction of enediynes is studied varying the position of the double bond in the starting reagent. It was observed that enediynes type yne-ene-yne preferred the standard [2+2+2] cycloaddition reaction, while enediynes type yne-yne-ene suffered β-hydride elimination followed a reductive elimination of Wilkinson’s catalyst giving cyclohexadiene compounds, which are isomers from those that would be obtained through standard [2+2+2] cycloaddition reactions. Finally, the last chapter of this thesis is based on the use of DFT calculations to determine the reaction mechanism when the macrocycles are treated with transition metals that are inactive to the [2+2+2] cycloaddition reaction, but which are thermally active leading to new polycyclic compounds. Thus, a domino process was described combining an ene reaction and a Diels-Alder cycloaddition.

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Qu’est-ce que la qualité au juste ? • Une catégorie esthétique qui relève du goût, toujours relatif ? • Une marque de commerce certifiant la fiabilité du produit, exposé à la contrefaçon ? • Une règle de déontologie appliquée à toute production humaine s’évaluant , aujourd’hui, par le service rendu, par la satisfaction du client, par la fidélisation de celui-ci ? • Le degré d’habilité technique ou professionnelle de l’artisan ? • Un jugement de valeur partagé entre l’objectivité et la subjectivité ? • Une mise en boîte brevetée ?

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El arte de la negociación es una estrategia fundamental en la toma de decisiones y un proceso mediante el cual las partes, en todas las áreas de la vida y en todas las disciplinas y profesiones, intentan resolver conflictos y llegar acuerdos, compatiblemente con sus necesidades e intereses. De una forma más sencilla, la negociación podría definirse como: “…cualquier comunicación entre dos o más personas con la intención de influenciar o persuadir” (R. Bordone, Harvard Law School, MA). Todos estos elementos destacan la importancia de desarrollar destrezas y competencias que fortalezcan este tipo de habilidad y la necesidad de conocer las reglas del juego de esta poderosa herramienta. Según la Escuela de Harvard, la forma más exitosa y provechosa de negociar es la recogida por el modelo integrativo-cooperativo, el que se base sobre premisas muy diferentes del tradicional modelo distributivo. Este último responde a nuestra forma de negociar más espontánea y lamentablemente desacertada, es decir, una forma de negociar que se reduce a un simple reparto de lo que haya sobre la mesa, sin visualizar, analizar posibles opciones negociadoras más allá de este simple reparto. Es un esquema que responde a una negociación “dura”, que se fundamenta en una concepción adversarial de las relaciones humanas (homo homini lupus, T. Hobbes), en donde hay un ganador y un perdedor, sin tintes intermedios. Al contrario, la idea con el modelo que propone la Escuela de Harvard, -el modelo integrativo-cooperativo-es uno por el que una negociación exitosa es aquella que “crea valor sobre la mesa” y que genera beneficios para todas las partes, no solo una de ellas. En otras palabras, el enfoque no es aquel por el que si uno pierde, el otro gana sino uno en el que la otra parte debe alcanzar un razonable nivel de satisfacción en sus requerimientos y demandas. Este modelo crea valor sobre la mesa inclusive más allá de los posibles beneficios que puedan conseguirse a partir de un determinado acuerdo; por ejemplo, ataja el conflicto y preserva las relaciones humanas, las que a menudo, en base al modelo tradicional (ganarperder) quedan perjudicadas. Finalmente, el modelo cooperativo es uno que abre la puerta a la empatía, la escucha activa, la transparencia y confianza; todos elementos que sin lugar a dudas facilitan las complejas relaciones interpersonales.

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Where does biology end and culture begin? While the human body is now widely accepted as being both biological and cultural, the brain is still considered by archaeologists as being a biological entity that provides the capacity for culture and is subject to no further change after the evolution of Homo sapiens. This article reviews recent research that suggests that the brain has continued to evolve at an increasing rate in recent times under the influence Of culturally created environments and that both the anatomy and function of individual brains can be manipulated by cultural behaviour. It describes an experiment in which one of us successfully changed his own brain in response to his cultural activity.

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An appropriate model of recent human evolution is not only important to understand our own history, but it is necessary to disentangle the effects of demography and selection on genome diversity. Although most genetic data support the view that our species originated recently in Africa, it is still unclear if it completely replaced former members of the Homo genus, or if some interbreeding occurred during its range expansion. Several scenarios of modern human evolution have been proposed on the basis of molecular and paleontological data, but their likelihood has never been statistically assessed. Using DNA data from 50 nuclear loci sequenced in African, Asian and Native American samples, we show here by extensive simulations that a simple African replacement model with exponential growth has a higher probability (78%) as compared with alternative multiregional evolution or assimilation scenarios. A Bayesian analysis of the data under this best supported model points to an origin of our species approximate to 141 thousand years ago (Kya), an exit out-of-Africa approximate to 51 Kya, and a recent colonization of the Americas approximate to 10.5 Kya. We also find that the African replacement model explains not only the shallow ancestry of mtDNA or Y-chromosomes but also the occurrence of deep lineages at some autosomal loci, which has been formerly interpreted as a sign of interbreeding with Homo erectus.

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Caliciviruses are a major cause of gastroenteritis in humans and cause a wide variety of other diseases in animals. Here, the characterization of protein-protein interactions between the individual proteins of Feline calicivirus (FCV), a model system for other members of the family Caliciviridae, is reported. Using the yeast two-hybrid system combined with a number of other approaches, it is demonstrated that the p32 protein (the picornavirus 2B analogue) of FCV interacts with p39 (2C), p30 (3A) and p76 (3CD). The FCV protease/RNA polymerase (ProPol) p76 was found to form homo-oligomers, as well as to interact with VPg and ORF2, the region encoding the major capsid protein VP1. A weak interaction was also observed between p76 and the minor capsid protein encoded by ORF3 (VP2). ORF2 protein was found to interact with VPg, p76 and VP2. The potential roles of the interactions in calicivirus replication are discussed.

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Human D-2Long (D-2L) and D-2Short (D-2S) dopamine receptor isoforms were modified at their N-terminus by the addition of a human immunodeficiency virus (HIV) or a FLAG epitope tag. The receptors were then expressed in Spodoptera frugiperda 9 (Sf9) cells using the baculovirus system, and their oligomerization was investigated by means of co-immunoprecipitation and time-resolved fluorescence resonance energy transfer (FRET). [H-3] Spiperone labelled D-2 receptors in membranes prepared from Sf9 cells expressing epitope-tagged D-2L or D-2S receptors, with a pK(d) value of approximate to 10. Co-immunoprecipitation using antibodies specific for the tags showed constitutive homo-oligomerization of D-2L and D-2S receptors in Sf9 cells. When the FLAG-tagged D-2S and HIV-tagged D-2L receptors were co-expressed, co-immunoprecipitation showed that the two isoforms can also form hetero-oligomers in Sf9 cells. Time-resolved FRET with europium and XL665-labelled antibodies was applied to whole Sf9 cells and to membranes from Sf9 cells expressing epitope-tagged D-2 receptors. In both cases, constitutive homo-oligomers were revealed for D-2L and D-2S isoforms. Time-resolved FRET also revealed constitutive homo-oligomers in HEK293 cells expressing FLAG-tagged D-2S receptors. The D-2 receptor ligands dopamine, R-(-) propylnorapomorphine, and raclopride did not affect oligomerization of D-2L and D-2S in Sf9 and HEK293 cells. Human D-2 dopamine receptors can therefore form constitutive oligomers in Sf9 cells and in HEK293 cells that can be detected by different approaches, and D-2 oligomerization in these cells is not regulated by ligands.