Search results for " Physical Geography"
showing 6 items of 6 documents
Cooling and societal change during the Late Antique Little Ice Age from 536 to around 660 AD
2016
Societal upheaval occurred across Eurasia in the sixth and seventh centuries. Tree-ring reconstructions suggest a period of pronounced cooling during this time associated with several volcanic eruptions. Climatic changes during the first half of the Common Era have been suggested to play a role in societal reorganizations in Europe1,2 and Asia3,4. In particular, the sixth century coincides with rising and falling civilizations1,2,3,4,5,6, pandemics7,8, human migration and political turmoil8,9,10,11,12,13. Our understanding of the magnitude and spatial extent as well as the possible causes and concurrences of climate change during this period is, however, still limited. Here we use tree-ring…
Isotope fractionation of zinc in the paddy rice soil-water environment and the role of 2’deoxymugineic acid (DMA) as zincophore under Zn limiting con…
2021
Non-traditional stable isotope systems are increasingly used to study micronutrient cycling and acquisition in terrestrial ecosystems. We previously proposed for zinc (Zn) a conceptual model linking observed isotope signatures and fractionations to biogeochemical processes occurring in the rice soil environment and we suggested that 2’deoxymugineic acid (DMA) could play an important role for rice during the acquisition of Zn when grown under Zn limiting conditions. This proposition was sustained by the extent and direction of isotope fractionation observed during the complexation of Zn with DMA synthesised in our laboratory. Here we report a new set of experimental data from field and labor…
Late Frasnian Atrypida (Brachiopoda) from the Ardenne shelf (southern Belgium)
2004
OMC: An Optical Monitoring Camera for INTEGRAL - Instrument description and performance
2003
The Optical Monitoring Camera (OMC) will observe the optical emission from the prime targets of the gammaray instruments onboard the ESA mission INTEGRAL, with the support of the JEM-X monitor in the X-ray domain. This capability will provide invaluable diagnostic information on the nature and the physics of the sources over a broad wavelength range. Its main scientific objectives are: ( 1) to monitor the optical emission from the sources observed by the gamma- and X-ray instruments, measuring the time and intensity structure of the optical emission for comparison with variability at high energies, and ( 2) to provide the brightness and position of the optical counterpart of any gamma- or X…
Importance des récentes variations pluviométriques à Djibouti et besoins de quantification de leurs impacts
2014
Ces dernières décennies, l’Afrique de l’Est souffre d’une longue et lente détérioration pluviométrique. De 2007 à 2011, la ville de Djibouti a enregistré un déficit de 73% des précipitations moyennes annuelles par rapport à la moyenne de 30 ans (1981-2010). Pour caractériser la sécheresse actuelle, nous analysons une série pluviométrique reconstruite pour Djibouti-Ville de 1901 à 2013, les données de terrain permettant d’illustrer les impacts de ces variations pluviométriques. Les précipitations enregistrées à Djibouti ne présentent aucune tendance sur le long terme (1901-2013). Par contre, ces dernières années montrent une très grande variabilité: le suivi de la moyenne pluviométrique sur …
Ecosystem service approach for land use management in agroecosystems in the mosaic-type landscape
2020
Promocijas darbs ir secīgu pētījumu kopa, kuras ietvaros ir izstrādāta daudzkritēriju lēmumu pieņemšanas atbalsta shēma zemes izmantošanas pārvaldības uzlabošanai mozaīkveida ainavu agroekosistēmās. Darba ietvaros tika aprobēts autoloģistiskās binārās regresijas modelis zemes izmantošanas maiņas virzītājspēku novērtēšanai Vidzemes augstienes mozaīkveida ainavā. Darba tapšanas laikā tika izstrādāta ekosistēmu pakalpojumu novērtēšanas un kartēšanas metode agroekosistēmām Vidzemes augstienē, un tālāk tā tika aprobēta visās Baltijas valstīs. Iegūtie rezultāti tika iestrādāti daudzkritēriju lēmumu pieņemšanas atbalsta rīkā un ir izmantojami teritoriju plānošanā un zemes pārvaldībā. Daudzkritērij…