Les éléments de parure au Paléolithique supérieur en Belgique

Considering that body ornaments are, through the choice of the elements, good cultural markers, along with the transitional geographical position of Belgium in the Palaeolithic, an up-to-date study of the body ornaments has been undertaken to catch the diffusion and contact phenomenon next to the influences in the lithic industries between regions. Despite the fact that the observations made take cultural value once they are considered in a broader frame than the actual political boarders of the country, cultural and chronological tendencies in terms of “fashions” within the Belgian material have nevertheless confirmed their informational potential.     

Les foraminifères du Paléocène et de l'Éocène basal du sillon nord-pyrénéen (Aquitaine, France)

This paper presents for the first time the inventory of the Paleocene and Lower Eocene foraminifers located in the North Pyrenean trough, between the Atlantic Ocean and the neighbourhood of the town Pau. They have been studied from three outcrops. The Bidart Beach section shows the Lasseube Formation from the Cretaceous/Paleogene boundary to the base of the P 3a zone. The Loubieng Quarry section, near Orthez, represents the upper P 3a zone and the lower P 3b zone as well as the Lasseube Formation / Pont Labau Formation boundary. The interval between the upper part of the P 3b zone and the upperest part of the P 5 zone crops out along the Gan - Rébénacq road with a hiatus located at the Paleocene / Eocene boundary, the whole interval belonging to the Pont Labau Formation. 394 taxons of foraminifers are present in this formations: 349 benthic and 45 planktonic species. The Velasco type benthic foraminifers show a middle bathyal depositional environment, with a paleobathymetry included between 500-600 m and 1000 m: Nuttallides truempyi, Osangularia velascoensis, Bulimina trinitatensis. The Midway type species which were transported by the turbidite currents from the lower to middle neritic environments are frequent as well as the Cretaceous reworked species. The species number is low: 29 in the iridium layer of the Cretaceous/Paleogene boundary (P 0 zone). Fauna grows rich quickly in the Pα zone reaching 129 species. The diversity grows up progressively from P α to the P 4a zone (NP 8). The disappearances are rare until his horizon, but their number is bigger than the number of appearances from the P 4b zone. It reaches their maximum between the P 4c zone and the P 5 zone. It shows that the decline of the Paleocene fauna begins around 2 million years before the thermal event of the Paleocene / Eocene boundary in the Aquitaine sections. The disappearances stay important in the Lower Eocene - Ypresian, but the appearance of lots of Eocene species show that the fauna renewal is located in this stage. The Cretaceous taxa dominate in the Paleocene benthonic fauna. The appearance or the disappearance of some species has a stratigraphic value in the Aquitaine region: the disappearance of Coryphostoma incrassata in the P 1b zone, the appearances of Plectina dalmatina, Elongobula grata (P α); Bulimina tuxpamensis (P 2); Tritaxilina cubensis, Thalmannita madrugaensis (P 3a); Svenia bulbosa (P 3b); Discorbis perovalis (P 4a/NP 7); Elongobula pulchra, E. pupa, Asterigerina bartoniana, Neorotalia gr. tuberculata (P 4a/NP 8); Bigenerina pannonica, Pentellina pseudosaxorum (P 5/NP 9-10).     

Effets du platine chez Brachydanio rerio (Téléostéen, Cyprinidé). I. Toxicité aiguë: bioaccumulation et histopathologie intestinales

Acute toxicity, accumulation and histological effects produced by various concentrations of platinum (H₂PtCl₆) in the intestine of Brachydanio rerio were investigated. Degenerative (lysis and necrosis of mucosal cells, changes in submucosa structure) and adaptative (fusion between villi) responses were revealed. The extent and the severity of the intestinal alterations were time- and concentration-dependent. Intestinal recovery was noted after 15 days of exposure to a sublethal Pt concentration (16 μg/L) followed by 64-day depuration. The characterization of the intestine responses in fish that were experimentally exposed to Pt can provide a basis for recognizing toxicity syndromes and should in fine be of use in the early prognosis of the effects of environmental aquatic Pt pollution.     

L'Intestin chez les Mugilidae (Poissons; Téléostéens) a différentes étapes de leur croissance I. Aspects morphologiques et histologiques

The intestine of Mugilidae (Pisces; Teleostei) at different growth stages. I. Morphological and histological aspects A morphological and histological study of the intestine of Mugilidae (Mugil cephalus, Liza aurata, Liza ramada and Liza saliens) has been carried out from the larval to the adult stages. The allometric relationship between length of intestine and standard length of fish are represented by regression lines correlated with species and kind of diet. S.E.M. observations on the intestinal mucosa surface show finger-like villi, as in Mammals. Histologically, the mucosa structure appears similar to that in others Teleosteans. The gobblet cells are scarce in the larval stages but very numerous in the juvenile stages; furthermore, they are more abundant in the posterior than the anterior part of the intestine (respectively 25 and 10%). Change in the feeding habits observed in young stages has no effect on the features of the intestine but notably increases its relative length.     

L'Intestin chez les Mugilidae (Poissons Téléostéens) à différentes étapes de leur croissance: II. Aspects ultrastructuraux et cytophysiologiques

The Intestines of the Mugilidae (Pisces Teleostei) at different growth stages. II-Ultrastructural and cytophysiological aspects The ultrastructures and functions of the columnar cells of the intestinal epithelia are characterized, from the larva to the adult stage: major transformations of the endoplasmatic reticulum, passage of SER/RER from 1 to 3, noticeable encrease of Golgi activity, development of lamellar structures forming a “mitochondrial pump” together with the basal mitochondria, at all levels of the intestine. Localized mainly in the posterior region of the juvenil stages, pinocytosis of the alimentary proteins and the associated lytic processus extend in the adult to the anterior region. Lipid absorption takes place essentially in the anterior part, resulting at all stages of development in the presence of lipid particles in the SER and in the intercellular spaces, and in the adult only in rare free lipid droplets in the cytoplasma. Correlations are rare between the evolution of organelles and cellular inclusions observed during the growth and the diet.     

Organisation spatiale des fibres de collagène de la plaque basale des écailles des Téléostéens

Spatial organization of collagenous fibrils in the basal plate of elasmoid scales has been studied in 36 species among 24 teleost families which include the whole order. Angle measurements of the various fibrillary directions were performed on fracture surfaces in frozen scales observed with the scanning electron microscope. The organization of the basal plate is arrayed in three basic patterns. The most remarkable one, found in the more "primitive" families, is a double twisted plywood with a left-handed rotation of the fibrillary directions. The remaining two are an orthogonal plywood, more or less regular, and an "intermediate" plywood, both found among the more "advanced" families. However, an orthogonal plywood is also observed in some "primitive" families, for example in Clupeidae and Salmonidae. We tentatively interpret the left-handed double twisted plywood of the lower teleosteans and of Amiidae as a synapomorphy in relation to the primitive condition of an actinopterygian lineage. On the other hand, within the teleosts, we would consider that the double twisted plywood is a plesiomorphic condition and that the orthogonal plywood is an apomorphy among the "advanced" teleosts families.