Les premières étapes de la colonisation de l’Europe et l’arrivée de l’Homme sur les rives de la Méditerranée

Over recent years, many discoveries have renewed our knowledge about the oldest stone industries and also about the behaviour and lifestyle of the hominids that made them, not only in East Africa, but also in the Near East, in Trans Caucasia and in southern Europe. If the first tools making hominids appear in East Africa as early as 2.55 million years ago, they are present in the Levant a little over 2 million years ago, as early as 1.81 million years ago at the gates of Europe in Trans-Caucasia, and a little over 1.4 million years ago on the Mediterranean coasts of Europe.     

Nouvelles recherches sur l’identité culturelle et stylistique de la grotte Chauvet et sur sa datation par la méthode du C

The discovery of Chauvet cave, at Vallon-Pont-d’Arc (Ardèche), in 1994, was an important event for our knowledge of palaeolithic parietal art as a whole. Its painted and engraved figures, thanks to their number (425 graphic units), and their excellent state of preservation, provide a documentary thesaurus comparable to that of the greatest sites known, and far beyond what had already been found in the group of Rhône valley caves (Ardèche and Gard). But its study – when one places it in its natural regional, cultural and thematic framework – makes it impossible to see it as an isolated entity of astonishing precocity. This needs to be reconsidered, and the affinities that our research has brought to light are clearly incompatible with the very early age which has been attributed to it. And if one extends this examination to the whole of the Franco-Cantabrian domain, the conclusion is inescapable: although Chauvet cave displays some unique characteristics (like every decorated cave), it belongs to an evolved phase of parietal art that is far removed from the motifs of its origins (known from art on blocks and on shelter walls dated by stratigraphy to the Aurignacian, in France and Cantabrian Spain). The majority of its works are therefore to be placed, quite normally, within the framework of the well-defined artistic creations of the Gravettian and Solutrean. Moreover, this phase of the Middle Upper Palaeolithic (26,000–18,000) coincides with a particularly intensive and diversified local human occupation, unknown in earlier periods and far less dense afterwards in the Magdalenian. A detailed critique of the treatment of the samples subjected to AMS radiocarbon dating makes it impossible to retain the very early age (36,000 cal BP) attributed by some authors to the painted and engraved figures of Chauvet cave.     

Influence relative de la BAP et de l'IBA sur la néoformation de bourgeons et de racines sur les plantules du Biota orientalis (Cupressacées)

Relative influence of BAP and IBA on the induction of adventitious buds and roots on plantelts of Biota orientalis (Cupressaceae)
Both cytokinin (BAP) and auxin (IBA) have an influence upon the intensity of adventitious bud induction in vitro on hypocotyls of Biota orientalis .
Increase in either the concentration or the length of contact with cytokinin enhances the mean number of neoformed buds per explant, while that of auxin results in an increase of the mean number of reactive explants as well as in the nature of neoformations. Auxin contributes to a restoration of the induction when the length of contact with cytokinin is too short. However, this synergism is only observed when the contract with IBA is simultaneous or follows that with contract with BAP.
Rhizogenesis is also influenced by the auxin-cytokinin balance. An increase in the duration of contact with IBA is always followed by an increased in the mean number of explants forming roots. This organogenesis may be partially or completely inhibited if the duration of contact with cytokinin – before, simultaneously or after that with auxin- exceeds two weeks.     

La stratigraphie et le Paléolithique du complexe saalien dans la région de la Saale et de l’Elbe

Some sediment sequences were known in the Elbe-Saale region. They enable a subdivision of the Saale complex, that is from Neumark Nord (Geisel valley), from Weimar-Ehringsdorf and Bad Kösen-Lengefeld (Saale valley). According to it, there are two interglacials between the Saalian groundmoraine (s.str.) and the Eemian. They are characterized by a strong subcontinental climatic influence, which could not be observed in the other interglacials of the Elbe-Saale region. The interglacials are connected with find horizons from the Middle Palaeolithic. They are concisely described here with their inventories.     

Action de la kinétine sur la croissance et la teneur en chlorophylles des racines

Lens roots form chlorophylls in well-developed chloroplasts when they are cultivated in continuous light. Chlorophyll accumulation was increased when kinetin (10^?4M) was added for a short time (24 h) of treatment. For a long time (72 h), the increase of chlorophyll content was reduced when roots were cultivated in light and with kinetin. When the roots were transferred from light to dark, chlorophyll content was decreased. This reduction was inhibited when roots were treated with kintin. From these present result it was supposed that kinetin acts on the catabolism and the anabolism of chlorophyll. The necessity of kinetin for chloroplast from amyloplast maturation and differentiation was discussed.     

Influence de l'intensité et de la longueur d'onde de la lumière sur le rendement des radicaux libres dans les semences de tomate et de carotte

Influence of light intensity and wavelength on the yield of free radicals in seeds of tomato and carrot.
Seeds of tomato ( Lycopersicum esculentum L. cv. Gribovsky-1180) and carrot ( Daucus carota L. cv. Santanet) were irradiated by continuous light of different wavelengths (white, blue, green, red, far-red and He-Ne laser) and different power density. Free radical output was measured using Electron Spin Resonance spectra (ESR). The dependence of the content of free radicals (FR) on the light power density was established. The yield of FR in the seeds irradiated with monochromatic light of the same power density was inversely proportional to the wavelength. The ESR spectra showed maximum absolute number of FR for white light. Successive irradiations gave cumulative effects on the output of free radicals in both directions: increase by the action of white light and decrease by the action of red and far-red light. The contact of irradiated seeds with steam decreased the amount of FR.     

Caractérisation de la production particulaire par l’oursin Echinometra mathaei sur les récifs Indo-Pacifiques : influence des peuplements coralliens et implications sur la dynamique sédimentaire

The characteristics of the sedimentary grains produced by the sea urchin Echinometra mathaei were described from two reef sites: a fringing Acropora-dominated reef at La Reunion island (Indian Ocean) and a barrier Porites-dominated reef at Moorea island (French Polynesia). The composition of the sediment produced by Echinometra was determined from SEM observations. The size and shape of the particles were measured by using image analysis method. The grain diameters range between a few micrometres and 2 mm, with a large predominance (more than 80 %) of particles smaller than 400 μm. The grain size distribution is dependent on the nature of the grazed substratum. Echinometra individuals collected at La Reunion on branching Acropora colonies produce a higher proportion of particles smaller than 200 μm compared to those collected at Moorea on massive Porites colonies. At Moorea, more grains having a diameter comprised between 200 and 500 μm are produced. The microstructure of coral substrata affects the mean particle diameter, which is 192,17 μm for a Acropora substratum and 244,69 μm for a Porites substratum. Since the sediment derived from Acropora erosion is finer, the proportion of suspended material that is exported from the reef is greater at La Reunion than at Moorea. We estimate that, for similar erosion rates and hydrodynamic conditions, the production of sands by Echinometra mathaei is higher and the retention of this erosional sediment more effective on reefs dominated by massive Porites than on Acropora-dominated reefs. This result is in accordance with the proportions of suspension-moving grains that have been previously measured on Moorea and La Reunion reefs. This study highlighted the effect of coral communities on the production of particles related to the bioerosion and on the sedimentary budget.     

Donnè Structurales et Ultrastructurales Nouvelles sur la Conjugaison de Paramecium caudatum.

The morphologic phenomena of the conjugation of Paramecium caudatum are analysed by transverse sectioning of couples at the level of the junction zone. This orientation allows exact determination of the adjacent surfaces (which strongly suggests the absence of a paroral cone) and their relation to the ciliary fields. The modifications of the outer pellicle are studied with the electron microscope. It is shown that cytoplasmic communications occur at the top of the ridges which limit the periciliary depressions. The kinetosomes remain apparently intact but cilia and trichocysts disappear. An active role by the latter organelles is suggested for the union of the two conjugants.     

Réflexion sur l’extension de l’Ibéromaurusien au Maghreb à la fin du Pléistocène

This paper proposes a new reflection about the late Pleistocene climate impact on the iberomausian coastal expansion. A recent advancement of palaeoenvironment knowledge allows us from now to apprehend a context and circumstances in which are developed diverse late Pleistocene cultures in the Maghreb. This article tries to understand a cultural dynamic of this period by the light of a contemporary climatic evolution.     

Effet de la chimiothérapie sur la fonction testiculaire et ovarienne

Recent advances in the treatment of cancer now permits long-term remissions and can cure a large amount of young. It is now well established that infertility and premature menopause are common consequences of successeful treatment. Much is known about the fertility and sexual effects of chemotherapy and allow development of new strategies to reduce infertilty. Alkylating agents are among the most commonly used chemotherapy agents and are for the most part highly gonadotoxic. Other drugs like cisplatin, vinca alkaloids, epipodophyllotoxins and antibiotics have moderate intrinsic toxicity whereas antimetabolites exert little if any toxic effect. Nevertheless, drugs are often used in combinations which are more toxic than single agents. Gonadal toxicity is usually dose dependant. Infertility is more frequent in males than in females and prepubertal girls have better prognosis though prepubertal ovaries are profoundly affected by chemotherapy. The onset of chemotherapy-related ovarian failure is age related but the risk of premature menopause still exists in women who recover menstrual cycles after amenorrhea. Fertility is usually worse after Hodgkin’s disease and testes cancer than after other cancers. No teratognesis in the offspring was published so far after chemotherapy. Nevertheless, men and women should be expressly discouraged from being party to a conception while they are receiving cancer therapy. Adults surviving to cancer should wait at least two years after completion of therapy before attempting parenthood.     

Effet de divers sels alcalins sur la croissance et la nutrition minérale de Lemna minor L

Lemna minor L. was grown in aseptic culture solutions. With sodium chloride or lithium chloride in the solution, the plant increased in yield. Tolerance of Lemna minor to relatively high level of sodium explains the presence of this plant in brackish waters. A low quantity of potassium is required for optimal growth. Sodium was added to nutrient solutions as chloride or sulphate. At equivalent levels the sodium content of the plant was somewhat higher under sulphate salinity.     

Imagerie hybride dans l’embolie pulmonaire aiguë : apport de la TDM couplée à la tomoscintigraphie de ventilation et de perfusion

Purpose

V/P-SPECT lung scan can be combined with computerized tomography (CT) from hybrid camera. We investigated if CT data could be use only with perfusion scans for the diagnosis of acute pulmonary embolism (PE).

Patients and methods

In a retrospective study, 75 consecutives patients, referred for suspicion of PE, underwent SPECT ventilation and perfusion scans coupled with a CT on Symbia T2. The perfusion images (P-SPECT) were classified as normal or abnormal with systematized (segmental and sub-segmental) or not systematized perfusion abnormalities. The ventilation images (V-SPECT) were considered as normal or abnormal in light of perfusion defects. The same was done for CT images. Correlations between V-SPECT and CT were studied.

Results

Hence, 28 patients had a normal P-SPECT and did not have PE. Patients (47) had an abnormal P-SPECT (among them, 16 turned out to have PE and 31 did not). There were 192 perfusion abnormalities of which 81 were segmental and 81 sub-segmental. Corresponding to these abnormalities, V-SPECT and CT were concordant in 83 % of the cases. When not-concordant, V-SPECT abnormalities with normal CT were found in 14 % of the cases and CT abnormalities with normal V-SPECT were found in 3 % of the cases. According to the EANM guidelines for PE diagnosis, sensitivity was 88 % and specificity 93 % with V/P-SPECT and 100 % and 83 % respectively with CT/P-SPECT (p = NS).

Conclusion

V/P-SPECT remains slightly more specific for the diagnosis of PE. However, this study demonstrates that CT/P-SPECT obtained with hybrid camera could be used for PE diagnosis with performances similar to V/P-SPECT. If these results would be confirmed on larger populations, this could lead to a significant reduction of scanning time which would improve patient comfort and reduce the camera load.