De acuerdo con las proyecciones del Consejo Nacional de Población (Conapo), la Zona Metropolitana de la Ciudad de México (zmcm) albergará una población de más de 21 millones de habitantes para 2020. Suponiendo que estas estimaciones fueran correctas, es importante prever en dónde se llevará a cabo este crecimiento y cómo afectará la estructura urbana. En este ensayo se analizan tres escenarios de expansión metropolitana elaborados conforme a diferentes supuestos de densidad poblacional y estimados mediante un análisis estadístico espacial por medio del Sistema de Información Geográfica (SIG). Los resultados revelan una expansión de la superficie urbana para el año 2020, según el escenario, de entre 38 mil y 56 mil hectáreas. Se concluye que se requieren de modelos de administración pública metropolitana conjunta para controlar la forma de expansión y para regular los usos de suelo de la ZMCM. AbstractAccording to the forecasts of the National Population Council (Conapo), by 2020, the Mexico City Metropolitan Zone (MCMZ) will house a population of over 21 million in­habitants. Assuming that these estimates are correct, it is important to predict where this growth will take place and how it will affect the urban structure. This essay analyzes three scenarios of metropolitan expansion drawn up on the basis of different assumptions of population density and estimates through a spatial statistical analysis using the Geographical Information System. The results reveal an expansion of the urban area by the year 2020, according to the scenario, of between 38,000 and 56,000 hectares. The authors conclude that models of joint metropolitan public administration are required to control the form of expansion and regulate mcmz land uses.

The significance of Latin America (LA) in the global food supply is large and prominent. The livestock sector at this time faces social-ecological challenges that will be accentuated in the future and will be incredibly challenging for small and medium producers. We conducted a systematic literature review to understand the role of LA cattle ranching in the current sustainability debate. In addition, we identified the main components of cattle ranching social-ecological systems and evaluated the institutional and ecological interactions of livestock studies by identifying spatial and temporal scales. Our results show a broad debate on livestock sustainability in LA; nevertheless, efforts to measure sustainability and analyze cattle ranching systemically are scarce. The study of LA cattle ranching in the 21st century was geographically concentrated on the main producing countries (Mexico, Colombia, Brazil, and Argentina) and was consistently promoted by government and academic institutions aiming to understand management strategies that improve yields. However, it less often focused on analyzing their impacts on ecosystems and climate. The complexity and dynamism of cattle ranching in LA make it necessary to address sustainable planning from a systemic approach to guide viable transformations through spatial scales.

The original outbreak of SARS-CoV-2 virus (COVID-19) occurred in the province of Wuhan, China, in November 2019 [1]. It then spread rapidly worldwide and was categorized as a pandemic by the World Health Organization (WHO) in 2020 [2]. During the progress of the pandemic in several regions of the world, it was observed that being […]

(2008). First Late Jurassic dinosaur bones from Chile. Journal of Vertebrate Paleontology: Vol. 28, No. 2, pp. 529-534.

Background. The COVID-19 pandemic has caused an exponential increase in the demand for medical care worldwide. In Mexico, the COVID Medical Units (CMUs) conversion strategy was implemented. Objective. To evaluate the CMU coverage strategy in the Mexico City Metropolitan Area (MCMA) by territory. Materials. The CMU directory was used, as were COVID-19 infection and mobility statistics and Mexican 2020 census information at the urban geographic area scale. The degree of urban marginalization by geographic area was also considered. Method. Using descriptive statistics and the calculation of a CMU accessibility index, population aggregates were counted based on coverage radii. In addition, two regression models are proposed to explain (1) the territorial and temporal trend of COVID-19 infections in the MCMA and (2) the mobility of the COVID-infected population visiting medical units. Results. The findings of the evaluation of the CMU strategy were (1) in the MCMA, COVID-19 followed a pattern of contagion from the urban center to the periphery; (2) given the growth in the number of cases and the overload of medical units, the population traveled greater distances to seek medical care; (3) after the CMU strategy was evaluated at the territory level, it was found that 9 out of 10 inhabitants had a CMU located approximately 7 km away; and (4) at the metropolitan level, the lowest level of accessibility to the CMU was recorded for the population with the highest levels of marginalization, i.e., those residing in the urban periphery.