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Résultats de la recherche (326 résultats)

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  • Late Holocene climatic changes in western equatorial Africa inferred from pollen from Lake Sinnda, southern Congo
  • Aridity ; C 14 dating ; Climatic variation ; Congo ; Holocene ; Lacustrine sediment ; Palaeoclimate ; Palynology ; Pollen diagram
  • Pollen analysis of 2 cores from the Lake Sinnda, located in one of the driest areas of the southern Congo, reveals a history of vegetation and climate in this region during the past 5000 yr. A major change centered around 3000-2500 yr B.P
  • . is indicated by an abrupt decrease in forest pollen and by a corresponding increase in grassland pollen. Concurrent drying up of the lake shows that climate, in particular aridity, was the major cause of this change. The aridity predates agriculture marked
  • by pollen of the oil palm at Lake Sinnda.
  • 1998
  • Tracing 4,000 years of environmental history in the Cuzco Area, Peru, from the pollen record
  • Agriculture ; Agroforestry ; Andes ; C 14 dating ; Holocene ; Human impact ; Impact ; Lacustrine sediment ; Land use ; Palaeo-environment ; Palynology ; Peru ; Pollen diagram
  • study is an analysis of the pollen record from Maracocha, an in-filled lake basin at 3,300 m near Ollantaytambo, which indicates an agricultural landscape more than 4,000 years ago. There also was evidence of three contrasting land-use phases associated
  • 1998
  • C 14 dating ; Erratic boulder ; European part of Russia ; Fluvioglacial features ; Historical geography ; Ladoga Lake ; Lake ; Palaeogeography ; Palaeolimnology ; Palynology ; Pollen analysis ; Quaternary ; Sedimentary structure ; Theory
  • by the Ice Age theory. With the introduction of new methods, such as pollen analysis and radiocarbon dating, these reconstructions have later become more detailed and exact.
  • 1998
  • Coastal plain ; France ; Holocene ; Human impact ; Hérault ; Languedoc-Roussillon ; Palaeobiogeography ; Pollen analysis ; Pool ; Quaternary ; Vegetation ; Vegetation dynamics
  • 1998
  • Atmospheric circulation ; Carbon ; Clay mineral ; Holocene ; Isotope analysis ; Lacustrine sediment ; Monsoon ; Oxygen 18 ; Palaeogeography ; Palaeolake ; Palynology ; Saudi Arabia ; Yemen
  • depression. The section dates from 8700 to 7200 yr B.P. and records an early phase of flooding followed by distinct lacustrine development from 7800 to 7200 yr B.P., coeval with maximum activity of the Indian monsoon. Comparison of the pollen record
  • with modern pollen deposition suggests that regional vegetation was then already of desert type and was related to strong seasonal trade winds.
  • 1998
  • Trace-element analysis of the calcareous shells of ostracodes in a sediment core from Farewell Lake provides the first limno-geochemical record for climatic reconstructions in Alaska. When compared with pollen data from the same site, this record
  • 1998
  • and pollen analysis of buried and intercalated organic horizons, and 3) on determining the origin and provenance of these deposits. The wider significance of this site for understanding the evolution of high-level aeolian deposits is then assessed.
  • 1998
  • Asian part of Russia ; C 14 dating ; Charcoal ; Climatic variation ; Forest ; Forest fire ; Geochemistry ; Holocene ; Humid environment ; Isotope analysis ; Palaeo-ecology ; Peat bog ; Pollen analysis ; Quaternary ; Siberia
  • Discussion des résultats des analyses de la carotte de tourbe et de boue organique lacustre, prélevée dans une tourbière polygonale dans la vallée de la rivière Lena, en Sibérie : datation C 14, pollens, plantes macrofossiles, stomatocystes
  • 1998
  • Australia ; C 14 dating ; Charcoal ; Coastal environment ; Estuary ; Holocene ; New South Wales ; Palaeo-environment ; Palynology ; Pollen analysis ; Sea level
  • 1998
  • France ; Haute-Garonne ; Holocene ; Midi-Pyrénées ; Palaeo-environment ; Palaeoclimate ; Palynology ; Pleistocene ; Pollen analysis ; Prehistory ; Quaternary
  • 1998
  • Diverse functions of convenience stores in the Tokyo metropolitan area : classification with sales analysis of POS data, and spatial implications
  • Cluster analysis ; Competition ; Consumer behaviour ; Honshu ; Japan ; Location ; Market ; Retail trade ; Spatial choice ; Store ; Tokyo ; Typology
  • This paper aims to analyse the functions of convenience stores. The author uses the factor analysis. - (KA)
  • 1998
  • Maximum entropy spectral analysis for the estimation of fractals in topography
  • Technical and software bulletin 1998
  • Colorado ; Fractal geometry ; Methodology ; Model ; Spatial variation ; Spectral analysis ; Texas ; Topography ; United States of America
  • The aim of this paper is to explore the use of autoregressive maximum entropy spectral analysis for the construction of power spectra, and the use of these spectra for the calculation of fractal dimension for both simulated and real topographic
  • surfaces. Comparisons will be made with one of the few published examples of the application of this estimation method for the analysis of topography and calculation of fractal dimension.
  • 1998
  • Désindustrialisation ; Développement industriel ; Emploi ; Emploi industriel ; Industrialisation ; Roumanie ; Shift-share analysis
  • Deindustrialization ; Employment ; Industrial development ; Industrial employment ; Industrialization ; Romania ; Shift-share analysis
  • Using the shift and share analysis, this paper is an essay for the understanding of the factors that direct the industrial restructuration of Romania. The article emphasizes the role of the political factor within the present industrial processes
  • 1998
  • Flood frequency analysis under non-stationarity
  • The objective of flood frequency analysis is to relate the magnitude of annual peak flow discharges to their frequency of occurrence through the use of probability distributions. In this study a time trend is investigated in the first two moments
  • , i.e. in the Mean value and the Standard Deviation (SD), and it is assumed to be a continuous function of time. Preliminary results of a flood frequency analysis for Polish rivers obtained with the IDT (Identification of Distribution and Trend) package
  • 1998
  • Grain-size analysis by laser diffractometry : comparison with the sieve-pipette method
  • Clay mineral ; Grain size distribution ; Methodology ; Soil ; Soil properties ; Soil science ; X-ray diffraction analysis
  • Results of a traditional sedimentation technique for grain-size analysis (the sieve-pipette method) were compared with those of a laser diffraction grain-size analyser, the Coulter LS-100. Milled quartz samples and silty soil samples were used
  • 1998
  • China ; Coal ; Core-periphery ; Energy resources ; Iron ; Multivariate analysis ; Oil ; Ore ; Regional development ; Regional disparities
  • The paper presents an exploratory undertaking to analyse the positive aspects of mineral activity in regional development during the past over 40 years in China. The results of applying factor analysis and cluster analysis indicate that the socio
  • 1998
  • Economic complexity as network complication : multiregional input-output structural path analysis
  • Input-output model ; Matrix analysis ; Multiplicator ; Multiregional model ; Network ; Regional economy ; Social accounting ; System
  • 1998
  • Combined analysis of digital terrain models and remotely sensed data in landscape investigations
  • This article presents a review of the combined analysis of digital terrain models (DTMs) and remotely sensed data in landscape investigations. The utilization of remotely sensed data with DTMs has become an important trend in geomatics in the past
  • 1998
  • Geomorphological and sedimentological analysis of a catastrophic flash flood in the Arás drainage basin (Central Pyrenees, Spain)
  • in the Betés subbasin. Two stages in the development of the flood have been differentiated from the sedimentological and morphological analysis of the flooded fan lobe : peak discharge and discharge decline.
  • 1998
  • A comparative analysis of nebkhas in central Tunisia and northern Burkina Faso
  • This paper reports a comparative analysis of nebkha morphology in central Tunisia and northern Burkina Faso based on a total of 473 measured nebkhas. Nebkhas are mounds composed of wind-borne sediment that accumulated around shrubs. The importance
  • 1998