In Neotropical rain forests, fresh mammal dung, especially that of howler monkeys, constitutes an important resource used by dung beetles as food and for oviposition and further feeding by their larvae. Tropical rain forest destruction, fragmentation, and subsequent isolation causing reductions in numbers of and the disappearance of howler monkeys may result in decreasing numbers of dung beetles, but this has not been documented. In this study, we present information on the presence of howlers and dung beetles in 38 isolated forest fragments and 15 agricultural habitats. Howler monkeys were censused by visual means, while dung beetles were sampled with traps baited with a mixture of howler, cow, horse, and dog dung. Results indicated that loss of area and isolation of forest fragments result in significant decrements in howlers and dung beetles. However, dung beetle abundance was found to be closely related to the presence of howler monkeys at the sites and habitats investigated. Scenarios of land management designed to reduce isolation among forest fragments may help sustain populations of howler monkeys and dung beetles, which may have positive consequences for rain forest regeneration.

We project an important increase in the prevalence of ESRD for 2025 which will be greater in the Mexican states with more marginality. This will increase health inequities already present and represent important challenges for health care financing, especially if no action is taken to control the causes and progression of ESRD.

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El presente trabajo plantea una visión general en torno al panorama actual del mundo laboral desde la práctica administrativa principalmente. Se hace un recuento somero de los principales acontecimientos históricos que han marcado un hito en el desarrollo y evolución del derecho del trabajo; se plasma una serie de concepciones consideradas básicas en relación con las nociones de derecho administrativo, derecho del trabajo y derecho social. Posteriormente se establecen los parámetros de la compleja función administrativa mediante la cual se materializan las normas de nuestro orden jurídico que regulan la actividad administrativa y rigen los derechos individuales y colectivos de los trabajadores. Asimismo, se fija el marco de actuación en materia laboral que guía las tareas del Ejecutivo Federal en general, y de la Secretaría del Trabajo y Previsión Social en lo particular. A manera de conclusión se pondera el importante papel que el derecho administrativo tiene en el ámbito de aplicación del derecho laboral.