Search results for " United-States"
showing 3 items of 3 documents
2016
AbstractUnderstanding the dynamics of zoonotic pathogens in their reservoir host populations is a prerequisite for predicting and preventing human disease epidemics. The human infection risk of Puumala hantavirus (PUUV) is highest in northern Europe, where populations of the rodent host (bank vole, Myodes glareolus) undergo cyclic fluctuations. We conducted a 7-year capture-mark-recapture study to monitor seasonal and multiannual patterns of the PUUV infection rate in bank vole populations exhibiting a 3-year density cycle. Infected bank voles were most abundant in mid-winter months during years of increasing or peak host density. Prevalence of PUUV infection in bank voles exhibited a regul…
Brown Carbon Aerosol in Urban Xi'an, Northwest China: The Composition and Light Absorption Properties.
2018
Light-absorbing organic carbon (i.e., brown carbon or BrC) in the atmospheric aerosol has significant contribution to light absorption and radiative forcing. However, the link between BrC optical properties and chemical composition remains poorly constrained. In this study, we combine spectrophotometric measurements and chemical analyses of BrC samples collected from July 2008 to June 2009 in urban Xi'an, Northwest China. Elevated BrC was observed in winter (5 times higher than in summer), largely due to increased emissions from wintertime domestic biomass burning. The light absorption coefficient of methanol-soluble BrC at 365 nm (on average approximately twice that of water-soluble BrC) w…
Modéliser la suburbanisation
2002
L’histoire de la suburbanisation de la population et de l’emploi, principalement aux Etats-Unis, permet d’identifier trois caracteristiques du phenomene. 1/ La suburbanisation se traduit par un etalement urbain tel que population et emploi s’accroissent plus en peripherie qu’au centre. 2/ La suburbanisation fait emerger de nouvelles concentrations d’activites dans la peripherie des villes-centres et donne naissance a des structures urbaines multicentriques. 3/ La suburbanisation differencie les contenus et les fonctions economiques des centres et recompose les centralites urbaines. Dans ce cadre, la suburbanisation se presente selon des modalites differentes selon les epoques et les regions…