42 resultados para Allen, Aaron S
Resumo:
Catalonia was the only Mediterranean region among the early followers of the British Industrial Revolution in the second third of the nineteenth century. The roots of this industrialisation process can be traced back to the seventeenth and eighteenth centuries when the Catalan economy became successfully integrated in international trade and the region enjoyed an intensification of its agrarian and proto-industrial activities. These capitalist developments were subsequently reinforced by a successful printed calico manufacturing business concentrated in the city of Barcelona. Although the factory system was largely adopted by the cotton industry in the 1840s, the diffusion of the spinning jenny had occurred earlier in the 1790s. In this paper, in line with Allen (2009a, 2009b), we explore whether relative factor prices played a role in the widespread adoption of the spinning jenny in Catalonia.
Resumo:
Catalonia was the only Mediterranean region among the early followers of the British Industrial Revolution in the second third of the nineteenth century. The roots of this industrialisation process can be traced back to the seventeenth and eighteenth centuries when the Catalan economy became successfully integrated in international trade and the region enjoyed an intensification of its agrarian and proto-industrial activities. These capitalist developments were subsequently reinforced by a successful printed calico manufacturing business concentrated in the city of Barcelona. Although the factory system was largely adopted by the cotton industry in the 1840s, the diffusion of the spinning jenny had occurred earlier in the 1790s. In this paper, in line with Allen (2009a, 2009b), we explore whether relative factor prices played a role in the widespread adoption of the spinning jenny in Catalonia.
Resumo:
High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.
Resumo:
Stalled replication forks are sources of genetic instability. Multiple fork-remodeling enzymes are recruited to stalled forks, but how they work to promote fork restart is poorly understood. By combining ensemble biochemical assays and single-molecule studies with magnetic tweezers, we show that SMARCAL1 branch migration and DNA-annealing activities are directed by the single-stranded DNA-binding protein RPA to selectively regress stalled replication forks caused by blockage to the leading-strand polymerase and to restore normal replication forks with a lagging-strand gap. We unveil the molecular mechanisms by which RPA enforces SMARCAL1 substrate preference. E. coli RecG acts similarly to SMARCAL1 in the presence of E. coli SSB, whereas the highly related human protein ZRANB3 has different substrate preferences. Our findings identify the important substrates of SMARCAL1 in fork repair, suggest that RecG and SMARCAL1 are functional orthologs, and provide a comprehensive model of fork repair by these DNA translocases.
Resumo:
De acuerdo con los planteamientos de la Terapia Cognitiva (TC) de Aaron Beck y la terapia Racional Emotivo Conductual (TREC) de Albert Ellis, el mantenimiento de creencias rígidas y actitudes disfuncionales constituyen factores de vulnerabilidad a los trastornos psicológicos. En base a estos planteamientos, la adecuada evaluación de las creencias y actitudes disfuncionales es fundamental, no sólo para saber cuáles están en el origen y mantenimiento de la perturbación emocional que puede aquejar a una persona, sino también para su cambio y prevención, e incluso para la promoción de actitudes más funcionales o saludables.El presente estudio se centra específicamente en el análisis de las similitudes y diferencias existentes entre los instrumentos de evaluación de las creencias y actitudes disfuncionales elaborados desde tales enfoques teóricos. Concretamente, entre el Inventario de Actitudes y Creencias (ABI) y la Escala de Actitudes Disfuncionales (DAS) desarrollados desde la perspectiva de la TREC y la TC, respectivamente. Para ello se han administrado sendos cuestionarios a una muestra de 156 estudiantes universitarios con un rango de edad comprendido entre los 19 y 57 años (media: 22.03; desviación típica: 5.09), y sus puntuaciones se han sometido a diversos análisis de correlación (de Spearman y canónica) y de regresión para verificar el grado de variancia compartida, así como a un análisis factorial de componentes principales (ACP) para comprobar la estructura de la agrupación de las escalas respectivas...
Resumo:
High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.
Resumo:
La reciente implantación y extensión de la red de alta velocidad ferroviaria en España está permitiendo relanzar un debate que en muchas ciudades no había sido resuelto de forma satisfactoria: la integración del ferrocarril en el medio urbano. En muchos casos, la llegada del nuevo tren se ha convertido en un instrumento urbanístico de primer orden, ya que conlleva una transformación de gran calado. En este artículo se realiza una lectura transversal, a través de las experiencias de diferentes ciudades españolas, para desarrollar una clasificación de las formas de integración de la alta velocidad ferroviaria y su impacto en la estructura urbana.
Resumo:
Objective: To compare lower incisor dentoalveolar compensation and mandible symphysis morphology among Class I and Class III malocclusion patients with different facial vertical skeletal patterns. Materials and Methods: Lower incisor extrusion and inclination, as well as buccal (LA) and lingual (LP) cortex depth, and mandibular symphysis height (LH) were measured in 107 lateral cephalometric x-rays of adult patients without prior orthodontic treatment. In addition, malocclusion type (Class I or III) and facial vertical skeletal pattern were considered. Through a principal component analysis (PCA) related variables were reduced. Simple regression equation and multivariate analyses of variance were also used. Results: Incisor mandibular plane angle (P < .001) and extrusion (P = .03) values showed significant differences between the sagittal malocclusion groups. Variations in the mandibular plane have a negative correlation with LA (Class I P = .03 and Class III P = .01) and a positive correlation with LH (Class I P = .01 and Class III P = .02) in both groups. Within the Class III group, there was a negative correlation between the mandibular plane and LP (P = .02). PCA showed that the tendency toward a long face causes the symphysis to elongate and narrow. In Class III, alveolar narrowing is also found in normal faces. Conclusions: Vertical facial pattern is a significant factor in mandibular symphysis alveolar morphology and lower incisor positioning, both for Class I and Class III patients. Short-faced Class III patients have a widened alveolar bone. However, for long-faced and normal-faced Class III, natural compensation elongates the symphysis and influences lower incisor position.
Resumo:
En aquesta nota aportem noves dades corològiques de Trifolium diffusum Ehrh. als Països Catalans i confi rmem la seva presència a Catalunya.
Resumo:
En la present nota indiquem un seguit de novetats corològiques per a la flora vascular dels massissos de les Guilleries i del Collsacabra.
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Juncus rechingeri es una especie anual afín a Juncus bufonius L. que fue recientemente reportada como nueva para Europa por Romero Zarco (2008). Hasta entonces sólo se conocía su distribución asiática (Afganistán -de donde proviene el tipo-, Anatolia, Pakistán, Irán y Asia central), pero no se conocía su presencia en el Mediterráneo oeste.
Resumo:
A Monte Carlo simulation study of the vacancy-assisted domain growth in asymmetric binary alloys is presented. The system is modeled using a three-state ABV Hamiltonian which includes an asymmetry term. Our simulated system is a stoichiometric two-dimensional binary alloy with a single vacancy which evolves according to the vacancy-atom exchange mechanism. We obtain that, compared to the symmetric case, the ordering process slows down dramatically. Concerning the asymptotic behavior it is algebraic and characterized by the Allen-Cahn growth exponent x51/2. The late stages of the evolution are preceded by a transient regime strongly affected by both the temperature and the degree of asymmetry of the alloy. The results are discussed and compared to those obtained for the symmetric case.