Risks of dengue secondary infective biting associated with aedes aegypti in home environments in Monterrey, Mexico

Abstract. Secondary dengue virus infections are a major risk for developing dengue hemorrhagic fever. Recent exposure to infectious bites of Aedes aegypti (L.) females in previously diagnosed dengue cases fulfills the epidemiological model of dengue hemorrhagic fever. A study was comprised of 357 (89.2%) dengue and 43 (10.8%) dengue hemorrhagic fever cases confirmed by laboratory tests and clinical manifestations. An entomological survey was done in homes and backyards. Concurrently, a questionnaire was used to assess the impact of healthpromotion campaigns through knowledge of the vector and its epidemiological role. Seventy-six (28.4%) of the 268 (67.0%) total wet or dry oviposition sites were positive for the presence of larvae or pupae, while adult Ae. aegypti were found in 32 (8.0%). One hundred thirty-two (33%) householders who formerly had dengue fever or dengue hemorrhagic fever had knowledge of either larval or adult dengue vector stages. According to gender distribution, 145 (36.2%) and 14 (3.5%) of the males confirmed with cases of dengue and dengue hemorrhagic fever lived in houses with 17.9 and 2% of the Ae. aegypti larval and pupal habitats. Houses with females who had dengue and dengue hemorrhagic fever were 212 (53%) and 29 (7.3%), with containers with immature Ae. aegypti in 19.4 and 7%, respectively. Lack of sustainability of government-targeted health education campaigns is the major problem for involving communities in prevention and control of dengu

Mathematical modeling of a catalytic pyrolysis depolymerization process

Catalytic Pyrolysis of polymers is a process which is gaining relevance due to several economic and ecological reasons. The process exists since more than two decades ago, but only now seems to be viable for the production of fuels in a sustainable and economic manner. On the other hand, although several attempts have been made to model the process, these attempts have used oversimplifications and empirical approaches that do not contribute much to the understanding and improvement of the process. In this paper we present a new and detailed approach to the modeling of this process based on the mechanism of carbenium ions, valid for zeolite type catalysts, the family of the most effective catalysts used in this process. The model starts from the full molecular weight distribution of the polymer to be processed, and describes in detail how the polymer is broken into simpler species that can be used as fuels after proper separation processes. The model is built from first principles based on the most viable kinetic mechanisms known and available kinetic constants with minimum data fitting, resulting in a large system of ordinary differential equations that are solved numerically. The model predictions are compared with previously published data for model systems and are applied to the depolymerization of high density polyethylene