1,538 research outputs found

    Resurgent vector-borne diseases as a global health problem.

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    Vector-borne infectious diseases are emerging or resurging as a result of changes in public health policy, insecticide and drug resistance, shift in emphasis from prevention to emergency response, demographic and societal changes, and genetic changes in pathogens. Effective prevention strategies can reverse this trend. Research on vaccines, environmentally safe insecticides, alternative approaches to vector control, and training programs for health-care workers are needed

    Thermoelectric cross-plane properties on p- and n-Ge/SixGe1-x superlattices

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    Silicon and germanium materials have demonstrated an increasing attraction for energy harvesting, due to their sustainability and integrability with complementary metal oxide semiconductor and micro-electro-mechanical-system technology. The thermoelectric efficiencies for these materials, however, are very poor at room temperature and so it is necessary to engineer them in order to compete with telluride based materials, which have demonstrated at room temperature the highest performances in literature [1]. Micro-fabricated devices consisting of mesa structures with integrated heaters, thermometers and Ohmic contacts were used to extract the cross-plane values of the Seebeck coefficient and the thermal conductivity from p- and n-Ge/SixGe1-x superlattices. A second device consisting in a modified circular transfer line method structure was used to extract the electrical conductivity of the materials. A range of p-Ge/Si0.5Ge0.5 superlattices with different doping levels was investigated in detail to determine the role of the doping density in dictating the thermoelectric properties. A second set of n-Ge/Si0.3Ge0.7 superlattices was fabricated to study the impact that quantum well thickness might have on the two thermoelectric figures of merit, and also to demonstrate a further reduction of the thermal conductivity by scattering phonons at different wavelengths. This technique has demonstrated to lower the thermal conductivity by a 25% by adding different barrier thicknesses per period

    Dengue Hemorrhagic Fever in Bantul, Jogyakarta, Indonesia

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    An epidemiological investigation of DHF outbreak was done from November to Desember 1976 in Bantul, which is an agricultural district located 25 kilometers south east Jogjakarta, Central Jawa. One hundred and twenty six cases were studied and 97 or 73% were confirmed as dengue infecti­on, the case fatality rate was 3.1%. The median age was 7 years and male to female ratio was 1:1.8. Clinically the observed cases ranged in severity from undifferentiated fever to shock and death. Dengue type, 1, 3 and 4 were isolated but dengue 3 was the predominant virus with 60% (27) isolates. Dengue type 1 and 4 were isolated also in equal numbers. Both A. Aegypti and A. albopictus showed a diversity of breeding habitats. While A. aegypti preferred the large cement tans and A. Albopictus cut bamboo stumps, there was considerable overlapping many breeding sites were shared by the 2 species

    The role of pathology in an investigation of an outbreak of West Nile encephalitis in New York, 1999.

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    An outbreak of encephalitis occurred in New York City in late August 1999, the first caused by West Nile virus in North America. Histopathologic and immunopathologic examinations performed on human autopsy materials helped guide subsequent laboratory and epidemiologic investigations that led to identification of the etiologic agent
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