983 resultados para C. Grandis L. Osbeck


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Six sites (759-764) were drilled on the Exmouth Plateau during Ocean Drilling Program Leg 122. Nannofossilrich Cenozoic sediments were recovered at all six sites, reflecting the open-ocean conditions that prevailed over the Exmouth Plateau during the Cenozoic. Calcareous nannofossils are abundant, diverse (250 different species identified), and generally well preserved throughout the composite lower Paleocene to Quaternary section. The diversity and preservation of nannofossils permits a high degree of stratigraphic resolution at each site. Site 762 on the central part of the Exmouth Plateau contains an almost unbroken Cenozoic record (only Miocene Zones NN3, NN8, and NN10 are missing). This site may prove to be a useful Cenozoic biostratigraphic and biomagnetochronologic reference section for the eastern Indian Ocean.

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Calcareous nannofossils are abundant in the Paleogene sediments recovered during Ocean Drilling Program Leg 120. Although no continuous Paleogene section was obtained, Sites 747 through 751 complemented each other so as to provide a virtually complete composite stratigraphic section. The calcareous nannofossil biostratigraphy at Sites 747, 748, and 749 is discussed. Correlation of calcareous nannofossil biozones and magnetozones at these sites suggests some diachrony with low-latitude areas, as well as on a regional basis. Changes in calcareous nannofossil diversity throughout the Paleogene are analyzed and interpreted as reflecting major paleoclimatic events.

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A relatively complete lower Paleocene to lower Oligocene sequence was recovered from the Southern High of Shatsky Rise at Sites 1209, 1210, and 1211. The sequence consists of nannofossil ooze and clay-rich nannofossil ooze. Samples from these sites have been the target of intensive calcareous nannofossil biostratigraphic investigations. Calcareous nannofossils are moderately preserved in most of the recovered sequence, which extends from nannofossil Zones CP1 to CP16. Most traditional zonal markers are present; however, the rarity and poor preservation of key species in the uppermost Paleocene and lower Eocene inhibits zonal subdivision of part of this sequence.

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Six sites were drilled on the southern Iberia Abyssal Plain during Ocean Drilling Program (ODP) Leg 173. Three holes (1067A, 1068A, and 1069A) recovered Eocene sediments consisting of thinly bedded turbidite deposits with interbedded hemipelagic sediments (Bouma sequence Te) deposited near the calcite compensation depth. The hemipelagic sediments are barren of nannofossils, necessitating the use of the turbidite deposits to erect an Eocene biostratigraphy for these holes. Moderately preserved, diverse assemblages of nannofossils were recovered from silty clays (Bouma sequence Td) and poorly preserved, less diverse assemblages were recovered from sandy/silty clays (Bouma sequence Tc). Hole 1067A has a continuous record of sedimentation (Subzones CP9a-CP14a) and Holes 1068A and 1069A have similar continuous records (Subzones CP9a-CP12a), although all holes contain barren intervals. Holes 1067A, 1068A, 1069A, 900A (ODP Leg 149), and 398D (Deep Sea Drilling Project Leg 47B) display a similar increase in mass accumulation rates in the lowermost middle Eocene. A reliable Eocene biostratigraphy has been erected using nannofossil data from turbidite sequences, allowing for correlation between Iberia Abyssal Plain sites.

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25 datasets (13 fossil leaf and pollen assemblages, 12 quantitative palaeoclimatic datasets) are provided in order to analyse Early Miocene palaeoclimate in Kazakhstan. The rich fossil record in Kazakhstan documents that during the Oligocene and Early Miocene this area in Central Eurasia was densely forested with warm-temperate deciduous trees and shrubs of the so-called "Turgayan flora". 29 fossil floras from 13 localities have been selected for a quantitative analysis of the Aquitanian (early Early Miocene) climate situation in Kazakhstan. The assessed mean annual temperatures generally place around 15 °C, while values of mean annual precipitation are of about 1000 mm. In combination with several other climate parameters estimated (temperatures of warmest and coldest months, precipitation rates of wettest, driest and warmest months), these data reflect uniform climatic conditions over several thousands of square kilometres. Data of temperature parameters show slight spatial differentiations, with generally cooler mean annual temperatures and higher seasonality (i.e. warmer summers and colder winters) in the north-eastern part of the study area compared with the south-western area around Lake Aral. As compared with palaeoclimate estimates for the European and East Asian Aquitanian, the central part of the Eurasian continent reveals evident signals of higher seasonality and slightly increased continentality.

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Five sites were drilled on the Iberia Abyssal Plain, west of the Iberian Peninsula. Four holes (897C, 897D, 899B, and 900A) yielded Eocene sediments that consist of turbidites and contourites. The Eocene section above the continental crust at Site 900 is continuous (from nannofossil Zones NP10 to NP20) and considerably expanded because of the site's relatively shallow depth, which remained consistently above the carbonate compensation depth (CCD). Sites 897 and 898, situated in deeper water above the ocean/continent transition, on the other hand, have noncontinuous, relatively short Eocene sections (from Zones NP14 to NP20 at Site 897 and from Zones NP19 to NP20 at Site 899). Nannofossils are abundant, diverse, and moderately to poorly preserved; they provide the primary means of dating the Eocene sediments recovered during Leg 149.

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Attributed to Alphonse Cerfberr by the Catalogue of the Bibliothèque nationale.

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Mode of access: Internet.

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The Pd(II) and Pt(II) complexes with triazolopyrimidine C-nucleosides L-1 (5,7-dimethyl-3-(2',3',5'-tri-O-benzoyl-beta-D-ribofuranosyl-s-triazolo)[4,3-a]pyrimidine), L-2 (5,7-dimethyl-3-beta-D-ribofuranosyl-s-triazolo [4,3-a]pyrimidine) and L-3 (5,7-dimethyl[1,5-a]-s-triazolopyrimidine), [Pd(en)(L-1)](NO3)(2), (Pd(bpy)(L-1)](NO3)(2), cis-Pd(L-3)(2)Cl-2, [Pd-2(L-3)(2)Cl-4]center dot H2O, cis-Pd(L-2)(2)Cl-2 and [Pt-3(L-1)(2)Cl-6] were synthesized and characterized by elemental analysis and NMR spectroscopy. The structure of the [Pd-2(L-3)(2)Cl-4]center dot H2O complex was established by Xray crystallography. The two L-3 ligands are found in a head to tail orientation, with a (PdPd)-Pd-... distance of 3.1254(17) angstrom.L-1 coordinates to Pd(II) through N8 and N1 forming polymeric structures. L-2 coordinates to Pd(II) through N8 in acidic solutions (0.1 M HCl) forming complexes of cis-geometry. The Pd(II) coordination to L-2 does not affect the sugar conformation probably due to the high stability of the C-C glycoside bond. (c) 2006 Elsevier B.V. All rights reserved.

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Lo scopo di questa tesi è quello di verificare il livello di conoscenza riguardo alla trigonometria negli studenti del 4 anno della Scuola Secondaria di II grado e in quelli iscritti al primo anno del corso di studi in Matematica. Per analizzare al meglio le conoscenze che dovrebbero avere gli studenti, è stato osservato come affrontano questo argomento i libri di testo della scuola e quelli universitari. Sono stati osservati anche gli esercizi proposti dai libri, gli obiettivi di apprendimento e le indicazioni nazionali previste dal ministero.

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Grâce à l'élaboration de sa théorie opératoire du développement cognitif, Jean Piaget fut, sans contredit, l'un des auteurs les plus écoutés dans ce domaine. Il a mis en lumière une série de stades du développement cognitif allant du niveau sensori-moteur en passant par le niveau des opérations concrètes pour finalement aboutir à celui des opérations formelles qui obéissent à des lois précises de construction (Piaget, 1964). Parmi celles-ci, Piaget affirme l'universalité du développement de ces stades en ce sens que tous les sujets passent par la même séquence. Il s'est très peu intéressé aux différences inter-individuelles. Ce qui explique que la très grande majorité de ses travaux ont portés sur l'observation de sujets normaux (Inhelder, 1963). Ce fut donc d'autres chercheurs qui ont tenté d'appliquer la pensée piagétienne à des catégories précises de sujets. Dans cette veine, la présente recherche s'intéresse à l'application de cette pensée aux déficients profonds. C'est l un moyen utile de tester l'universalité de la séquence de développement proposée par Piaget. Le relevé de documentation sur cette question proposée par Klein et Safford (1977) permet de constater qu'il est relativement aisé de trouver des recherches s’intéressant à l'étude du fonctionnement cognitif des déficients mentaux lgers atteignant la période des opérations concrètes mais qu'il est beaucoup plus difficile d'en trouver qui s'attardent au fonctionnement cognitif des déficients profonds. Il est pourtant possible d'en trouver quelques-unes (Ciccheti et Sroufe, 1976; Inhelder, 1963; Kahn, 1976; Lambert et Vanderlinden, 1977; Rogers, 1977; Silverstein et al., 1975; Wohlueter et Sindberg, 1975; Woodward, 1959). Les résultats divergent. De plus, une analyse approfondie des méthodologies utilisées suffit à convaincre que le débat demeure ouvert sur cette question. Des améliorations méthodologiques sont apportées dans cette recherche. La présente étude analyse donc le fonctionnement sensori-moteur des déficients profonds en le comparant à celui de sujets normaux de même âge mental qu'eux. Les déficients mentaux sont divisés en deux groupes selon qu'il y ait ou non présence de trouble lsionnel. Tous les sujets font face aux items de l'échelle de la poursuite visuelle et de la permanence de l'objet ainsi que celle des relations entre les objets dans l'espace construits par Uzgiris et Hunt (1975). Les résultats sont ensuite tour à tour présentés et interprétés.