1000 resultados para Ion lourd et rapide
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Examination of samples from eight outcrops from Albian and Cenomanian of Estremadura, induced to take a census of sixty-two species and subspecies of Ostracodes among which fifteen are new and described here. Their associations pennited - first, to characterize three faunistic sets: a lower and middle Albian set with a mediolittoral and infralittoral (shallow marine} sedimentation; an upper Albian s.l. (near formations of Rudists}; a lagoonal lower Cenomanian; - on the other hand, to state local comparisons with the middle Cretaceous of Southern France, of the South-pyrenean Zone (Sierra d' Aulet: district of Sopeira), of the district of Oviedo (Northwestern Spain), and of the Aragonese Iberian Range (Aragon and Maestrazgo), placing in a prominent position faunistic exchanges of Ostracodes between the above-mentioned regions and the Estremadura, during the lower Cenomanian.
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This paper presents a resume of the results achieved by researchers of the Centro de Estratigrafia e Paleobiologia da U. N. L. on the Neogene of Algarve, since 1977. The detailed study of several profiles as well as that af calcareous nannoplanton, planktonic foraminifera, ostracoda, fishes and mammals allowed to obtain data and correlation elements leading to a new interpretation of the Miocene of Algarve. It was possible to date and to characterize the following units: a) Carbonate formation of Lagos-Portimão, of marine facies, ascribed to the Lower Miocene (Aquitanian? and mainly Burdigalian), possibly attaining the Lower Langhian. b) Essentially arenaceous series of continental facies with a marine intercalation of Arrifão, Olhos de Água and Auramar Hotel beach, middle Miocene (Langhian-Serravallian) in age. c) Marine (tripoli, conglomerates, sands and limestones) deposits of Tunes-Mem Moniz, Ponte das Lavadeiras (Faro), Arroteia (Fuzeta) and Luz de Tavira, corresponding, at least partially, to the first part of the upper Miocene (Lower Tortonian). d) Cacela formation with three members: The lower member (conglomerates and sands), the middle (yellow silts) and the upper ones (gray silts), uppermost Tortonian and mainly Messinian in age. An interpretation of the tectonic and paleogeographic evolution of the portuguese littoral during the Miocene is also presented considering its insertion in the meridional part of the Peninsula (Guadalquivir depression, Betic massif basins and in the spanish Levant in general). Comparisons among the Neogene vulcanism of this region and similar manifestations documented in Algarve (basanite of Figueira-Portimão, etc) are established.
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A bone breccia from Goldra, near Loulé, is studied. It corresponds to the infilling of a karst depression, consisting of: rather worn and probably transported dolomite pebbles at the bottom; accumulations of frequently burnt bone scraps, much broken and with acute edges (no transport), certainly debris of human food, suggesting habitat level (s); in association with the former, stone (flint, quartz, quartzite, graywacke) rather uncharacteristic artifacts that seem compatible with middle and upper Paleolithic, or with Epipaleolithic; and small mammal teeth and bones. Fauna includes an extinct species, Microtus brecciensis recognized for the first time in Portugal. It is not older than Riss-Wiirm interglacial, and may be of this age or later, maybe that of one of wurm's first interstades. Fauna points out to a varied landscape with open country and woods; and to a rather warm and dry temperate, or dry subtropical mediterranean climate. Climate differences should not be significant in comparison with the extant situation. The presence of the mammal species found so far is consistent with modern distribution.
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A mammal (Anoplotherium cf. commune) and a land tortoise (Geochelone is. gen.] sp.) from the Ludian (Uppermost Eocene) locality of Côja have been identified. Age can be more accurately established now, from level 3 to level 5 in the Ludian stage, probably 4. Relationships between Côja's feldspathic sands, a correlative unit «Arenitos de Vale Furado», and the paroxysmal phase of pyrenean orogeny are confirmed.
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Two eocene ziphodont crocodillans (Ilberosuchus and Pristichampsus) are dealt with. Their distinction seems possible, even with isolated teeth. The association of both in some localities may account for some previous identification difficulties. Geographical and stratigraphical distribution indicated: for Pristichampsus from Germany to Spain, Cuisan to to Upper Lutetian; for Iberosuchus from France to Portugal, lower Lutetian to Bartonian and maybe Ludian.
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Teeth and astragali were used for a biometrical study concerning suids from V-a (upper Burdigalian) and V-b (Langhian) divisions from Lisbon's Miocene series. The Hyotherium (V-b) are identical to those from french localities, hence they all belong in the same species H. soemmeringi. Bunolistriodon populations from V-a and V-b are homogenous; no significant difference between them has been found, inspite of different geological age. Both may be ascribed to B. lockharti. No evolutive trend was detected. The presence of another form close to the north african B. massai could not be confirmed either. French localities' Bunolistriodon populations also seem homogenous and conspecific with those from Lisbon. Notwithstanding its essentially homogenous character, there can be distinguished two sets in both V-a and V-b populations according to M3 size; this remains to be explained, since the last molars are the most likely to show a broad range of variation and are not unequivocally related to sexual dimorphism. Classification of the rare Tayassuidae has been confirmed. All known taxa are shown (see tableau I).
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These work presents the quantitative and qualitative inventory and the stratigraphic distribution of fossil plants (spores, pollens, sterns, leaves and seeds) recognized the Miocene of the portuguese part of Tagus basin. For each lithostratigraphic unit, associations with ecological (paleoclimatic) meaning are defined. It was also possible to follow the evolution of the vegetation and the climate during the considered cronostratigraphic interval which includes most of the Miocene (Aquitanian to lower-middle Tortonian).
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New elements about the stratigraphy of the Serra de Candeeiros Dogger and Lower «Lusitanian» are presented. The Lower Aalenian was recognized for the first time. Bathonian (more than 50 metres thick) is dated on brachiopods and foraminifera. It corresponds to a series of massive micritic, biodetritical, coral-reef, chaetetid, bryozoa and oolitic-limestones. Callovian (120 m) begins by whitish or yellowish limestones with ammonites and brachiopods of the Gracilis zone. It is followed by regressive limestone sequences ending with thick oncolitic layers. The «Lusitanian» base is formed by greyish lagoon brackish limestones; it lies unconformably on the Dogger, with or without angular and/or cartographic unconformity. This radical facies change is related to tectonic deformation of several blocks between the Nazaré and Tagus faults during Oxfordian times.
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In Portugal, Carixian is generally represented by alternative layers of marly limestones characterized by nodule and lumpy levels. These layers are particularly developped [show preferential development] on passage areas to a sedimentary basin, particularly along the slope of tilted blocks between the Meseta and Berlenga's horst. This facies is included in the range of the «nodular limestone» and of the «ammonitico-rosso». Limestones are radiolaria micrites with fragments of pelagic organisms (ammonoids, thin shelled gastropods). These layers can be affected by intensive bioturbation (Brenha) which is responsible for dismantlement, specially where the initial thickness does not exceed a few centimetres. This process can lead to the isolation of residual nodules (Brenha, São Pedro de Muel, Peniche) which can be mobilised by massive sliding (Peniche). The isolated elements, shell fragments or residual nodules, can also be incrustated, thus developing oncolitic cryptalgal structures. At Brenha the lump structure developed progressively into a sequence overlapping the normal sedimentary one (thick limestone beds alternating with bituminous shales). Cryptalgal structures correspond to rather unstable environment conditions on mobile margins. These structures are known in deep pelagic sediments corresponding to well defined events of the geodynamic evolution (end of the initial rifting). Cryptalgal accretions disappear towards the sedimentary basin, and the nodular levels are less important. In the articulation areas with the Tomar platform, small mounds and cupules (Alcabideque) developed within the alternating marly-limestone levels. They represent the so called «mud mounds» of metric dimensions. The upper part of these «mud mounds» is hardened, showing track remains and supporting some brachiopods and pectinids. Hence the lumpy facies of Portugal is included among the range of sedimentaty environments and can be used as «geodynamic tracer».
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The synthetic study of the uppermost Cretaceous of the Beira Litoral (fauna, flora) confirms its upper Campanian-Maastrichtian age. It shows the presence of a tropical to subtropical climate in an area constituted by a low coastal plain only occasionally linked to the sea, saturated with fresh water and possessing accordingly, a predominantely freshwater fauna (Viso, Aveiro); this plain changed towards the interior into a drier more forested zone with a more abundant terrestrial fauna which includes mammals (Taveiro). A thorough study of the chelonian Rosasia, abundant on the coastal plain, was made possible thanks to the discovery of a skull: it demonstrates that the genus belongs to the family Bothremydidae, revalided here. The composition of this family is presented, its phylogenetic and paleobiogeographic relation with the other pleurodires are analyzed, and its diagnosis established. The family is constituted of three groups; Rosasia belongs to one of these, the Bothremys group.
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The study of new abundant coral crops and a systematic revision of the historic collections allow us to extend significantly the data about the Upper Oligocene and Miocene Scleractinia of the French atlantic basins. The SW and W-NW France faunas have been considered, and complete lists of the different defined taxa are presented. The generallines of the evolution of this group are specified, and linked to the paleoclimatic and paleobiogeographic changes.
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The behavior of copper(II) complexes of pentane-2,4-dione and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, [Cu(acac)(2) (1) and [Cu(HFacac)(2)(H2O)] (2), in ionic liquids and molecular organic solvents, was studied by spectroscopic and electrochemical techniques. The electron paramagnetic resonance characterization (EPR) showed well-resolved spectra in most solvents. In general the EPR spectra of [Cu(acac)(2)] show higher g(z) values and lower hyperfine coupling constants, A(z), in ionic liquids than in organic solvents, in agreement with longer Cu-O bond lengths and higher electron charge in the copper ion in the ionic liquids, suggesting coordination of the ionic liquid anions. For [Cu(HFacac)(2)(H2O)] the opposite was observed suggesting that in ionic liquids there is no coordination of the anions and that the complex is tetrahedrically distorted. The redox properties of the Cu(II) complexes were investigated by cyclic voltammetry (CV) at a Pt electrode (d = 1 mm), in bmimBF(4) and bmimNTf(2) ionic liquids and, for comparative purposes, in neat organic solvents. The neutral copper(II) complexes undergo irreversible reductions to Cu(I) and Cu(0) species in both ILs and common organic solvents (CH2Cl2 or acetonitrile), but, in ILs, they are usually more easier to reduce (less cathodic reduction potential) than in the organic solvents. Moreover, 1 and 2 are easier to reduce in bmimNTf(2) than in bmimBF(4) ionic liquid. (C) 2013 Elsevier B.V. All rights reserved.
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Cahiers d'ethnomusicologie, V.22, pp. 223-237
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Cet article se propose réfléchir à la présence créatrice du performer depuis la notion d’ambiance du choréographe japonais Y. Amagatzu. La notion d’ambiance est décrite par Yoshio Amagatzu comme une spatialité émergente de la rencontre des sujets – performers et public – dans l’espace performatif ; une spatialité sensible exprimant le potentiel de cette rencontre avec une « force orientatrice » spécifique. Mon approche s’intéresse en particulier aux conditions d’accordage (attunement) du performer au potentiel de cette spatialité émergente et aux effets de cette « adhérence perceptive» sur sa présence créatrice. Une approche qui m’a mené à étendre la notion de mouvement à l’espace de la relation performative, au delà des contours visibles du corps physique.
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Congrès de l’Association de Sociologues de Langue Française, Comité de Recherche n° 21 « Transactions Sociales », Istambul