968 resultados para Watson, Richard, 1737-1816.
Resumo:
Durante los años del colapso de la monarquía española, el Virreinato del Perú estuvo gobernado por Fernando de Abascal, quien, en alianza con la élíte de Lima, aplicó una política de represión en términos ideológicos y militares ante cualquier intento separatista o revolucionario, tanto dentro de su jurisdicción virreinal como fuera de ella, entre cuyos territorios vecinos estaban Quito, Chile y Charcas. Asimismo, mediante esta estrategia, el Virreinato de Lima intentó recuperar parte de la influencia perdida en América del Sur como consecuencia de la aplicación de las reformas borbónicas, especialmente durante la segunda mitad del siglo XVIII. El presente artículo pone atención a la respuesta de Lima contra al movimiento insurgente desatado en Quito a partir de 1809.
Resumo:
Las mujeres presas en el Hospicio de Quito durante los primeros treinta años de existencia constituyen el objeto de estudio del presente trabajo. A través de este sector circunscrito de la plebe quiteña se identifican algunas características sobre la forma en que “desde arriba” se proyectan las políticas y los mecanismos de control y algunas agencias que “desde abajo” se activan frente a la situación de disciplinamiento en la ciudad. Para abordar estas dos perspectivas se recurre a documentación oficial y a la búsqueda del “deber ser” institucional, al mismo tiempo que se procura recuperar la voz de los sectores subalternos, particularmente de las mujeres. El trabajo se asienta por lo tanto, en buena medida, en aquella documentación primaria que permite escuchar algunas de las preocupaciones de las mujeres relacionadas con sus experiencias. Específicamente se detectan algunas prácticas que activan frente a las injusticias que perciben y su reacción frente al incumplimiento de los objetivos de la institución definidos en el discurso ilustrado que justificaron su creación. Ambos temas traducen la percepción que tienen los sectores subalternos respecto a su rol y al del Hospicio.
Resumo:
Este estudio se propone recuperar las voces de algunas mujeres presas en el Hospicio Jesús, María y José, fundado en Quito en 1786, en el marco de las políticas sociales borbónicas de control de la población marginal de la ciudad. El Hospicio, creado para recluir a sujetos considerados improductivos –fundamentalmente, pobres-mendigos, ociosos y lazarinos–, también castigó con el encierro a mujeres imputadas de transgresiones sociales, con la intensión de redimirlas a partir del trabajo en la producción textil. Bajo la perspectiva de los nuevos enfoques respecto al concepto de control social, se pueden identificar algunos mecanismos que activaron las mujeres presas para elevar reclamos cuando percibían injusticias o para demandar su libertad. Esta perspectiva permite abordar el tema del control social bajo una doble visión: la forma como se proyecta el control desde «arriba», articulando diversas instancias de autoridad, y las respuestas de los sectores subalternos «desde abajo», activando no solo mecanismos de resistencia, sino también de agencia.
Resumo:
It has been previously demonstrated that extensive activation in the dorsolateral temporal lobes associated with masking a speech target with a speech masker, consistent with the hypothesis that competition for central auditory processes is an important factor in informational masking. Here, masking from speech and two additional maskers derived from the original speech were investigated. One of these is spectrally rotated speech, which is unintelligible and has a similar (inverted) spectrotemporal profile to speech. The authors also controlled for the possibility of “glimpsing” of the target signal during modulated masking sounds by using speech-modulated noise as a masker in a baseline condition. Functional imaging results reveal that masking speech with speech leads to bilateral superior temporal gyrus (STG) activation relative to a speech-in-noise baseline, while masking speech with spectrally rotated speech leads solely to right STG activation relative to the baseline. This result is discussed in terms of hemispheric asymmetries for speech perception, and interpreted as showing that masking effects can arise through two parallel neural systems, in the left and right temporal lobes. This has implications for the competition for resources caused by speech and rotated speech maskers, and may illuminate some of the mechanisms involved in informational masking.
Resumo:
Temperature-programmed reaction measurements supported by scanning tunneling microscopy have shown that phenylacetylene and iodobenzene react on smooth Au(111) under vacuum conditions to yield biphenyl and diphenyldiacetylene, the result of homocoupling of the reactant molecules. They also produce diphenylacetylene, the result of Sonogashira cross-coupling, prototypical of a class of reactions that are of paramount importance in synthetic organic chemistry and whose mechanism remains controversial. Roughened Au(111) is completely inert toward all three reactions, indicating that the availability of crystallographically well-defined adsorption sites is crucially important. High-resolution X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy show that the reactants are initially present as intact, essentially flat-lying molecules and that the temperature threshold for Sonogashira coupling coincides with that for C−I bond scission in the iodobenzene reactant. The fractional-order kinetics and low temperature associated with desorption of the Sonogashira product suggest that the reaction occurs at the boundaries of islands of adsorbed reactants and that its appearance in the gas phase is rate-limited by the surface reaction. These findings demonstrate unambiguously and for the first time that this heterogeneous cross-coupling chemistry is an intrinsic property of extended, metallic pure gold surfaces: no other species, including solvent molecules, basic or charged (ionic) species are necessary to mediate the process.
Resumo:
Asymmetric catalysis is of paramount importance in organic synthesis and, in current practice, is achieved by means of homogeneous catalysts. The ability to catalyze such reactions heterogeneously would have a major impact both in the research laboratory and in the production of fine chemicals and pharmaceuticals, yet heterogeneous asymmetric hydrogenation of C═C bonds remains hardly explored. Very recently, we demonstrated how chiral ligands that anchor robustly to the surface of Pd nanoparticles promote asymmetric catalytic hydrogenation: ligand rigidity and stereochemistry emerged as key factors. Here, we address a complementary question: how does the enone reactant adsorb on the metal surface, and what implications does this have for the enantiodifferentiating interaction with the surface-tethered chiral modifiers? A reaction model is proposed, which correctly predicts the identity of the enantiomer experimentally observed in excess.
Resumo:
Field experiments were conducted to quantify the natural levels of post-dispersal seed predation of arable weed species in spring barley and to identify the main groups of seed predators. Four arable weed species were investigated that were of high biodiversity value, yet of low to moderate competitive ability with the crop. These were Chenopodium album, Sinapis arvensis, Stellaria media and Polygonum aviculare. Exclusion treatments were used to allow selective access to dishes of seeds by different predator groups. Seed predation was highest early in the season, followed by a gradual decline in predation over the summer for all species. All species were taken by invertebrates. The activity of two phytophagous carabid genera showed significant correlations with seed predation levels. However, in general carabid activity was not related to seed predation and this is discussed in terms of the mainly polyphagous nature of many Carabid species that utilized the seed resource early in the season, but then switched to carnivory as prey populations increased. The potential relevance of post-dispersal seed predation to the development of weed management systems that maximize biological control through conservation and optimize herbicide use, is discussed.
Resumo:
Field experiments were conducted to quantify the natural levels of post-dispersal seed predation of arable weed species in spring barley and to identify the main groups of seed predators. Four arable weed species were investigated that were of high biodiversity value, yet of low to moderate competitive ability with the crop. These were Chenopodium album, Sinapis arvensis, Stellaria media and Polygonum aviculare. Exclusion treatments were used to allow selective access to dishes of seeds by different predator groups. Seed predation was highest early in the season, followed by a gradual decline in predation over the summer for all species. All species were taken by invertebrates. The activity of two phytophagous carabid genera showed significant correlations with seed predation levels. However, in general carabid activity was not related to seed predation and this is discussed in terms of the mainly polyphagous nature of many Carabid species that utilized the seed resource early in the season, but then switched to carnivory as prey populations increased. The potential relevance of post-dispersal seed predation to the development of weed management systems that maximize biological control through conservation and optimize herbicide use, is discussed.