Precarización laboral y trabajo en plataformas digitales : el caso de Uber en la Ciudad de México de 2013-2021

Aurora Rebeca de la Rosa-Zapata (2022, [Tesis de doctorado])

"El propósito de esta investigación es analizar la dinámica laboral que subyace al modelo de negocios de la plataforma Uber a partir del estudio de su operación la Ciudad de México, desde su introducción hasta el año 2021".

Empleo precario; México; Aspectos sociales; Empleo precario; Aspectos tecnológicos; Trabajo y trabajadores; Aspectos económicos; Medios digitales; Aspectos laborales; Internet; Empresas comerciales extranjeras CIENCIAS SOCIALES CIENCIAS ECONÓMICAS ECONOMÍA DEL CAMBIO TECNOLÓGICO ECONOMÍA DEL CAMBIO TECNOLÓGICO

Contrasting spatial patterns in active-fire and fire-suppressed mediterranean climate old-growth mixed conifer forests

Danny L. Fry  (2014, [Artículo])

In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha-1, and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥56%) in large patches (≥10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.

article, climate, controlled study, ecosystem fire history, forest structure, geographic distribution, geographic mapping, land use, mathematical computing, mathematical model, Mexico, spatial analysis, taiga, United States, comparative study, conife CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA