920 resultados para 983
Resumo:
Exemplaire incomplet de son premier feuillet, avec lequel a disparu le nom de son auteur ; il est dédié à un sultan de Constantinople, dont les titres sont donnés au recto du premier feuillet, et dont le nom, Mourad III, fils de Selim II, se lit au feuillet 17 recto. Il se compose de tableaux astrologiques et astronomiques, dans lesquels on trouve les planètes figurées dans des médaillons, des prédictions, en particulier par les mouvements réflexes des membres. En tête de cet almanach, se voient des tableaux chronologiques, dans lesquels se trouve résumée l'histoire des dynasties antéislamiques de la Perse et des dynasties musulmanes qui ont précédé les Osmanlis.
Resumo:
Contient : 1° « Les Meditacions et clameurs de la glorieuse vierge Marie sur la Passion, complainte de Nostre Dame à l'Estache », en vers ; 2° « Le Livre du Tresor de sapience, lequel fist et composa maistre JEHAN JARSON » ; 3° L'Art de bien vivre, moralité en vers ; 4° « Les Enseignemens ARISTOTE de quantes natures contient l'omme en soy » ; 5° « L'Exposicion des fables Ysopet »
Resumo:
u.a. Semmeringfeier; Pessimismus; Deutscher Kaiser; Materialismus; Maria Magdalena; Sozialismus; Politik; Ungarn; König Humbert; Schopenhauer Rezeption in Japan; Buddhismus; China; Marokko; Russland; Waterloo; Giacomo Leopardi;
Resumo:
At ODP Site 983, relative geomagnetic paleointensity and planktic and benthic delta18O records have been acquired for the last 350 kyr. The mean sedimentation rate in this interval is 11.3 cm/kyr. Magnetic properties and hysteresis ratios indicate that pseudo-single domain magnetite is the remanence carrier. Volume susceptibility (kappa), anhysteretic (ARM) and isothermal (IRM) remanence values vary by a factor of 3-4, well within the criteria usually cited for paleointensity studies. Natural remanent magnetization (NRM) is normalized by ARM and IRM to acquire the paleointensity proxy. Arithmetic means of NRM/ARM and NRM/IRM, calculated for five demagnetization steps in the 25-45 mT range, constitute the relative paleointensity estimates. Some paleointensity lows (particularly those at ~40, ~120 and ~188 ka) are associated with directional excursions of the field, especially the event at ~188 ka (referred to here as the Iceland Basin Event) that constitutes a short-lived polarity reversal. For the last 200 kyr, the records can be correlated with other high-resolution paleointensity records such as those from the Labrador Sea, Mediterranean/Somali Basin and Sulu Sea, implying that the millennial scale features are globally synchronous. A labeling system for paleointensity features is proposed that ties prominent highs and lows to oxygen isotope stages.
Resumo:
The grain size of deep-sea sediments provides an apparently simple proxy for current speed. However, grain size-based proxies may be ambiguous when the size distribution reflects a combination of processes, with current sorting only one of them. In particular, such sediment mixing hinders reconstruction of deep circulation changes associated with ice-rafting events in the glacial North Atlantic because variable ice-rafted detritus (IRD) input may falsely suggest current speed changes. Inverse modeling has been suggested as a way to overcome this problem. However, this approach requires high-precision size measurements that register small changes in the size distribution. Here we show that such data can be obtained using electrosensing and laser diffraction techniques, despite issues previously raised on the low precision of electrosensing methods and potential grain shape effects on laser diffraction. Down-core size patterns obtained from a sediment core from the North Atlantic are similar for both techniques, reinforcing the conclusion that both techniques yield comparable results. However, IRD input leads to a coarsening that spuriously suggests faster current speed. We show that this IRD influence can be accounted for using inverse modeling as long as wide size spectra are taken into account. This yields current speed variations that are in agreement with other proxies. Our experiments thus show that for current speed reconstruction, the choice of instrument is subordinate to a proper recognition of the various processes that determine the size distribution and that by using inverse modeling meaningful current speed reconstructions can be obtained from mixed sediments.
Resumo:
A geochemical study of sediments from Ocean Drilling Program Site 983 was conducted to examine low-frequency variations in carbonate content as expressed by blue-band reflectance (450-500 nm) over the last 1.2 Ma. Sedimentary percent organic carbon, percent carbonate, and excess barium (Ba[ex]) were used as the primary tools to evaluate the factors responsible for these long-term changes. We observe positive correlation between the mass-accumulation rate of various biogenic components and the mass-accumulation rate of Ba(ex), especially in sediments younger than ~600 ka. Deeper in the section (~600-1200 ka), the correlation between Ba(ex) and the other biogenic tracers is weak. The lack of correlation between Ba(ex) and biogenic carbonate likely results either from a higher supply of terrigenous material at that time (which confounds Ba[ex] estimation), or remobilization of Ba resulting from low pore-water sulfate ion concentrations, or both. Nonbiogenic sediments at Site 983, represented by Th, K2O, and the molar Ti/Al ratio, exhibit cyclic variations that represent mixing between continental and oceanic (i.e., basaltic) terrigenous sources. The timing of these cycles matches that of the major glacial-interglacial cycles, which suggests that they result from the supply of continental material as ice-rafted debris during glacial periods and fine-grained basaltic material by bottom currents during interglacial periods. Given these observations, the most likely causes for the low-frequency carbonate variations observed in the Site 983 sediments are shifts in surface productivity and, to a lesser extent, dilution by the input of terrigenous material.