RESUMO
Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial-interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can provide continuous archives of upstream glacial activity, but few such records extend beyond the last glacial cycle. Here a piston core from Lake Junín in the uppermost Amazon basin provides the first, to our knowledge, continuous, independently dated archive of tropical glaciation spanning 700,000 years. We find that tropical glaciers tracked changes in global ice volume and followed a clear approximately 100,000-year periodicity. An enhancement in the extent of tropical Andean glaciers relative to global ice volume occurred between 200,000 and 400,000 years ago, during sustained intervals of regionally elevated hydrologic balance that modified the regular approximately 23,000-year pacing of monsoon-driven precipitation. Millennial-scale variations in the extent of tropical Andean glaciers during the last glacial cycle were driven by variations in regional monsoon strength that were linked to temperature perturbations in Greenland ice cores1; these interhemispheric connections may have existed during previous glacial cycles.
RESUMO
Since February 1977, five patients with cholera apparently acquired the infection from the riverine environment in Queensland. A total of 13 rivers have now yielded at least one isolate of Vibrio cholerae 01 biovar El Tor. Investigations indicate that the organism, including toxigenic strains, can survive and multiply in the riverine environment. No human or animal reservoirs and no ecological niches were identified and no route of importation or dissemination of the organism was discovered. The microbiological examination of faeces in all medical laboratories in Australia should include methods for detecting the cholera organism as a routine. When confronted with a cholera infection, medical practitioners should obtain a history of recent travel, both in Australia and overseas.
Assuntos
Cólera/etiologia , Reservatórios de Doenças , Água Doce , Água , Adulto , Austrália , Pré-Escolar , Cólera/epidemiologia , Cólera/prevenção & controle , Monitoramento Ambiental , Monitoramento Epidemiológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População , Vibrio cholerae/isolamento & purificação , Abastecimento de ÁguaRESUMO
In a coke oven study conducted by NIOSH, selected chemical analyses of airborne particulates, vapors, and metals in the emissions from five coke ovens were done. Eight sampling procedures and seven analytical techniques were used to analyze samples collected for the study. Six of the analytical methods used are discussed.