975 resultados para Caldwell, Robert Ernest, 1858-1904.
Rebelión en Galápagos: la hacienda "Progreso" de Manuel J. Cobos en la isla San Cristóbal, 1879-1904
Resumo:
El presente artículo es una investigación histórica, y una lectura desde el mirador de la teoría de los movimientos sociales, de la rebelión de los trabajadores de la hacienda “Progreso” de la isla San Cristóbal (Chatham) en Galápagos. La hipótesis que guía este trabajo es saber si el sistema socio-económico y de gobierno determinan o no el carácter violento de la acción colectiva. Se trata de un estudio de caso, para lo cual presentamos una aproximación al sistema socio-económico de la hacienda “Progreso” como forma social de producción supeditada al modo de producción capitalista, en el cual se inscribe la rebelión de Chatham. Seguidamente echamos mano del instrumental teórico de los movimientos sociales para elaborar una interpretación y exponer algunas reflexiones acerca de la violencia colectiva.
Resumo:
Mid-latitude weather systems are key contributors to the transport of atmospheric water vapour, but less is known about the role of the boundary layer in this transport. We expand a conceptual model of dry boundary-layer structure under synoptic systems to include moist processes, using idealised simulations of cyclone waves to investigate the three-way interaction between the boundary layer, atmospheric moisture and large-scale dynamics. Forced by large-scale thermal advection, boundary-layer structures develop over large areas, analogous to the daytime convective boundary layer, the nocturnal stable boundary layer and transitional regimes between these extremes.
Resumo:
The radiative forcing due to a distinct pattern of persistent contrails that form into contrail-induced cirrus near and over the UK is investigated in detail for a single case study during March 2009. The development of the contrail-induced cirrus is tracked using a number of high-resolution polar orbiting and lower-resolution geostationary satellite instruments and is found to persist for a period of around 18 h, and at its peak, it covers over 50,000 km2. The shortwave (SW) and longwave (LW) radiative forcing of the contrail-induced cirrus is estimated using a combination of geostationary satellite instruments, numerical weather prediction models, and surface observation sites. As expected, the net radiative effect is a relatively small residual of the much stronger but opposing SW and LW effects, locally totaling around 10 W m−2 during daylight hours and 30 W m−2 during nighttime. A simple estimate indicates that this single localized event may have generated a global-mean radiative forcing of around 7% of recent estimates of the persistent contrail radiative forcing due to the entire global aircraft fleet on a diurnally averaged basis. A single aircraft operating in conditions favorable for persistent contrail formation appears to exert a contrail-induced radiative forcing some 5000 times greater (in W m−2 km−1) than recent estimates of the average persistent contrail radiative forcing from the entire civil aviation fleet. This study emphasizes the need to establish whether similar events are common or highly unusual for a confident assessment of the total climate effect of aviation to be made.