879 resultados para BLACK HOLES
Resumo:
En el momento en que se activa la discusión del concepto de lo juvenil y de observar las representaciones e imaginarios que acompañan a este grupo etareo de la sociedad contemporánea, empiezan a aparecer nuevas nociones sobre las diferentes autoidentificaciones que circundan a los jóvenes. En este sentido se puede entender que los jóvenes son parte de un grupo social especial, sobre el cual recaen unos privilegios económicos de tiempo y de edad, de ahí que generalmente, el joven se distingue porque en cierta forma no se ha independizado de su familia nuclear, factor que ha facilitado para ser parte de nuevas formas del consumo en las industrial culturales y de construcciones de identidad a partir del consumo musical. Desde el relacionamiento del joven con el consumo de artefactos culturales, se pueden entender las construcciones identitarias que establece bajo parámetros muy específicos, de ahí que la cultura juvenil nos lleva a entender las identidades musicales que circundan en la sociedad juvenil contemporánea, identidades que parten desde el Rap, el Hip – Hop, el Reggae hasta el Rock, el Metal y el Black Metal. Este último segmento identitario de las culturas juveniles llama la atención porque aparenta ser una construcción que contiene unos valores sociales nuevos, puesto que la música (Black Metal) que guía dicha identidad tiene el propósito de romper los estereotipos sociales, religiosos, morales y políticos. Al establecerse el Black Metal como una cultura juvenil con un alto consumo en la ciudad de Quito nos encontramos con que los jóvenes pertenecientes a esta cultura tienen una concepción de familia que deviene de una construcción tradicional de la sociedad, pero que a su vez ellos reinterpretan y se rea-propian de esta forma de ser y estar en el mundo; de ahí que la noción de familia al interior del Black Metal no se construye como una entidad que es contraria a la concepción tradicional, por el contrario contiene parámetros monógamos heterosexuales. Se advierte además que se reformulan las prácticas de la sexualidad y la importancia que se le da a las mismas en la concepción de la construcción de una familia propia que se intenta sea adaptativa y que no reprima la construcción identitaria de los futuros hijos.
Resumo:
La presente tesis es un trabajo de investigación que trata sobre la aplicación del Modelo Black and Scholes para valorar empresas en el entorno ecuatoriano. Para tener una lógica sencilla y ordena se ha divido el trabajo en cuatro capítulos, los cuales tienen un objetivo específico cada uno y en su conjunto buscan responder las hipótesis planteadas en la tesis. El primer capítulo proporciona una idea general sobre los aspectos teóricos de la valoración de empresas, en este capítulo se encuentra la definición, los conceptos básicos, una explicación de cada uno de los métodos más importantes que se conoce actualmente. El propósito del capítulo es entender la valoración de empresas en su conjunto. El segundo capítulo se orienta en las bases conceptuales desarrolladas por el modelo Black and Scholes referente a valoración de opciones y su comparación con otros modelos, se toma este enfoque debido a que se cuenta con suficiente información para entender adecuadamente el modelo. La finalidad del capítulo es comprender el modelo de Black and Scholes para la valoración de opciones. El tercer capítulo analiza la aplicación del modelo Black and Scholes en la valoración de empresas a través de estudios previos, los fundamentos, las variables que se requieren y la forma de obtener las mismas. El capítulo tiene como propósito analizar la valoración de empresas aplicando el modelo Black and Scholes. El último capítulo se centra en realizar la aplicación práctica en el entorno ecuatoriano de valorar empresas a través del modelo Black and Scholes, en el mismo se describe paso a paso como se realizó la valoración y se detalla los resultados obtenidos. El objetivo del capítulo es aplicar los conocimientos desarrollados y obtener resultados que permitan tener fundamentos suficientes para obtener las conclusiones finales.
Resumo:
Understanding source-sink dynamics of game birds is essential to harvest and habitat management but acquiring this information is often logistically and financially challenging using traditional methods of population surveys and banding studies. This is especially true for species such as the American Black Duck (Anas rubripes), which have low breeding densities and extensive breeding ranges that necessitate extensive surveys and banding programs across eastern North America. Despite this effort, the contribution of birds fledged from various landscapes and habitat types within specific breeding ranges to regional harvest is largely unknown but remains an important consideration in adaptive harvest management and targeted habitat conservation strategies. We investigated if stable isotope (δD, δ13C, δ15N) could augment our present understanding of connectivity between breeding and harvest areas and so provide information relevant to the two main management strategies for black ducks, harvest and habitat management. We obtained specimens from 200 hatch-year Black Duck wings submitted to the Canadian Wildlife Service Species Composition Survey. Samples were obtained from birds harvested in Western, Central, and Eastern breeding/harvest subregions to provide a sample representative of the range and harvest rate of birds harvested in Canada. We sampled only hatch-year birds to provide an unambiguous and direct link between production and harvest areas. Marine origins were assigned to 12%, 7%, and 5% of birds harvested in the Eastern, Central, and Western subregions, respectively. In contrast, 32%, 9%, and 5% of birds were assigned, respectively, to agricultural origins. All remaining birds were assigned to nonagricultural origins. We portrayed probability of origin using a combination of Bayesian statistical and GIS methods. Placement of most eastern birds was western Nova Scotia, eastern New Brunswick, Prince Edward Island, and southern Newfoundland. Agricultural birds from the Central region were consistent with the Saguenay region of Québec and the eastern claybelt with nonagricultural birds originating in the boreal. Western nonagricultural birds were associated with broad boreal origins from southern James Bay to Lake of the Woods and east to Cochrane, Ontario. Our work shows that the geographic origins, landscape, and habitat associations of hatch-year Black Ducks can be inferred using this technique and we recommend that a broad-scale isotopic study using a large sample of Canadian and US harvested birds be implemented to provide a continental perspective of source-sink population dynamics.
Resumo:
The diffuse and regular reflectances of five optically absorbing coatings frequently used in optical systems, were measured over the 0.32-14.3 mu m wavelength range, before and after exposure to heat and intense optical radiation. The measured coatings included Nextel Velvet Black, an anodised coating and NPL Super Black. The anodised coating exhibited substantial variations in its diffuse and regular reflectance values after thermal and simulated solar ageing. Solar and thermal ageing of the Nextel Velvet Black resulted in increases of its reflectance. However, thermal ageing tended to decrease the reflectance of the other paint samples examined. Thermal and solar ageing of the NPL Super Black resulted in only minor changes in its reflectance characteristics. All measurements are traceable to the UK National Standards.
Resumo:
This paper illustrates the opportunities afforded by the adoption of postcolonial discourse in development geography, drawing specifically on issues of transnationalism, hybridity and inbetweeness. The utility of such notions and associated approaches is illustrated by the authors' current research on the migration of young, second generation and foreign-born 'Bajan-Brits' to the small Caribbean island nation of Barbados, the homeland of their parents. Focussing on issues of 'race' and gender, the paper examines the experiences of return migration among this cohort from an interpretative perspective framed within postcolonial discourse. It argues that notwithstanding the considerable sociocultural problems of adjustment encountered, these Bajan-Brit 'returnees' may be seen as occupying positions of relative economic privilege. Theirs is a liminal space derived by virtue of having been born and/or raised in the UK and being of the black 'race'. Accordingly, they are demonstrated to be both advantaged and disadvantaged; both transnational and national; and black but, in some senses, symbolically white.
Resumo:
The research presented in this article centres on an under-researched demographic group of young return migrants, namely, second-generation Barbadians, or 'Bajan-Brits', who have decided to 'return' to the birthplace of their parents. Based on 51 in-depth interviews, the essay examines the experiences of second-generation return migrants from an interpretative perspective framed within post-colonial discourse. The article first considers the Bajan-Brits and issues of race in the UK before their decision to migrate. It is then demonstrated that on 'return', in certain respects, these young, black English migrants occupy a liminal position of cultural, racial and economic privilege, based on their 'symbolic' or 'token' whiteness within the post-colonial context of Barbados. But this very hybridity and inbetweeness means that they also face difficulties and associated feelings of social alienation and discrimination. The ambivalent status of this transnational group of migrants serves to challenge traditional notions of Barbadian racial identity.
Resumo:
With both climate change and air quality on political and social agendas from local to global scale, the links between these hitherto separate fields are becoming more apparent. Black carbon, largely from combustion processes, scatters and absorbs incoming solar radiation, contributes to poor air quality and induces respiratory and cardiovascular problems. Uncertainties in the amount, location, size and shape of atmospheric black carbon cause large uncertainty in both climate change estimates and toxicology studies alike. Increased research has led to new effects and areas of uncertainty being uncovered. Here we draw together recent results and explore the increasing opportunities for synergistic research that will lead to improved confidence in the impact of black carbon on climate change, air quality and human health. Topics of mutual interest include better information on spatial distribution, size, mixing state and measuring and monitoring. (c) 2006 Elsevier Ltd. All rights reserved.