Modulation de la Réponse du Xyléme selon la Nature de l'Agression Vasculaire

Modulation of the xylem response to different types of vascular aggressions The evolution of cells lining the vessels in the stem xylem of carnation was compared in sham-stressed (s. e.), V. dabliae-infected (i V. d.) and P. cinerescens-infected (i P. c.) plants. All experimental stresses triggered ultrastructural changes leading to the appearance of new cell types. In parallel, vacuolar polyphenols were metabolized and dense-core vesicles appeared. These were early and independant phenomena. In all cases the reactions of carnation xylem were stronger against Verticillium than against Phialophora. Differences in vascular gummosis were disclosed whatever the criterion used (speed of installation, relative importance of the phenomenon, level of structural complexity, dynamics of appearance of the different structures). The possible relations between cell structures and gummous secretions were investigated by means of comparison of an efficient defence system (i V. d.) with a deficient one (i P. c.). All the criteria selected for analysis confirm that faced with a specific parasite the host response was disrupted. In other words, the biosynthetic pathways normally used by the plant after a fungal aggression were blocked, slowed or diverted. The differences in the responses of carnation to Verticillium and Phialophora give a picture of parasite specificity in agreement with the model recently proposed by de Wit (1981) for tomato/Cladosporium fulvum.     

Réexamen du contexte géologique,chrono- et biostratigraphique du site de Moulin Quignon à Abbeville (Vallée de la Somme,France)

The geological context of the discoveries made by Boucher de Perthes at Moulin Quignon in 1863–1864 was examined through the testimonies left by himself, by his detractors, then by geologists and archaeologists who later worked on the alluvial deposits of the Somme at Abbeville. This critical approach has been completed by specific studies, through a restricted excavation performed at Carpentier Quarrya locality known since the end of the 19th century as a sequence analogous to Moulin Quignon, and by a series of new analyses (microvertebrate, malacofauna, dating). The main results of these studies confirm the fluvial nature of the ‘archaeological’ layers at Moulin Quignon that correspond to a high terrace of the Somme River, about 40 m above the current valley incision at Abbeville. Dating results provide an age of 584 ± 48 ka for the fluvial levels at Carpentier Quarry, in good agreement with the available biostratigraphic data, inferred from malacofaunas collected at both Moulin Quignon (Boucher de Perthes collection) and Carpentier Quarry, and from mammals fauna recovered since the end of the 19th century from the white marl at Carpentier Quarry which allow the allocation of these alluvial deposits to an interglacial stage of the second half of the Cromerian, the marine isotopic stage (MIS) 15. From these data and taking into account the identification of the human remains of Moulin Quignon as an anatomically modern man, the contemporaneity of these remains with the alluvial deposits of a high terrace of the Somme River is virtually impossible and supports the hypothesis of a hoax. Besides, it is possible that at least some of the lithic material collected at the time of the discovery by Boucher de Perthes could derive from fluvial levels dated of approximately 600,000 years. They would be then the oldest evidence of a human presence in the Somme Valley.     

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.     

L'analogie et la représentation de l'art primitif à la fin du XIX siècle

In this paper, we will examine the foundations of Western representation of Paleolithic art at the end of the nineteenth century. Taking the period of 1864-1902 into account, we will prove the leading role of analogy between “modern primitive societies” and “prehistoric societies” in the very definition of “primitive art”. According to us, the representation of the “primitive artist” at that time was largely based in comparison between art which came from modern primitive societies living in Africa, Australia or America, and prehistoric art which was authenticated at about 1865. Through this examination, we will show the way in which analogy functions as a main category in the construction of scientific knowledge.     

Apports du site de Montclus (Gard) à l’origine et à la filiation du Montclusien (Mésolithique)

The Baume of Montclus is located in the Cèze valley (Gard). This site gave its name to a prehistoric tool-age, the Montclusian, which parted from the Sauveterrian. Middle and Upper Montclusian are present in Montclus, unlike the Lower Montclusian. The Montclusian industry, which starts here in about 8000 BP, includes a very high proportion of hypermicrolithes. It is followed by a Castelnovian industry from around 7000 BP. This one features very different Montclusian, showing thus a break. The Castelnovian survives in Montclus while the Cardial is already settled in Châteauneuf-les-Martigues and sites around the Ardèche river. After these Montclusian levels appear Cardial and Chassean layers. Neolithisation has been very gradual here, affecting tools first before the arrival of ceramic, around 6500 BP. What is the origin of Montclusian? And what could have become? Its origin might be further west with the Causses and Languedoc, where levels are rather similar. The Sauveterrian origin has long been established. But research shows a great diversity among the Sauveterrian originated industries. What the Montclusian was going to become is to discovered from the Lower Montclusian, quite original, and which should be found in other site. Montclusian might be on the geographic and cultural boderline of 2 districts: one being located west of the Rhône river, influenced by Sauveterrian, and which gave birth to Montclusian, the other east of the Rhône river bears witness to Castelnovian.     

Cancer de la prostate : utilité de la TEP-TDM à la F-fluorocholine

In oncology, positron emission computed tomography (PET/CT) has become an essential tool for initial staging, response evaluation and follow-up of cancer patients. Most of the frequent tumors (lung, breast, esophagus, and lymphomas) are highly avid for ¹⁸F-fluorodeoxyglucose (¹⁸FDG), but prostate cancer has not demonstrated significant uptake of FDG. The development of new tracers labeled with ¹⁸F such as choline analogs allowed already to obtain interesting results particularly in patients with biological relapse and inconclusive conventional imaging work-up. The impact of ¹⁸F-flurocholine PET/CT on patient management needs to be validated in large studies, but many centers use already this examination in order to guide further management, including radiotherapy planning.     

Un habitat de la fin du Mésolithique dans le Centre-Ouest de la France : L’Essart à Poitiers (Vienne)

The excavation of L’Essart (Poitiers) makes it possible for the first time in the west of France to understand a very particular habitat, along a river and very much marked by the firing activities. The substrate of the site assigns the shape of a dome surrounded to the east by the Clain River, to the west by a channel. Abundant vestiges allotted to the recent Neolithic lay in the lower half of a layer of brown silts. Immediately subjacent, a level of ten centimetres, located at the top of orange silts, contained burnt stones structures: 39 hearths (circular area posed flat approximately one meter of diameter) and 14 dismantled hearths. It is dated from the final Mesolithic by the extremely abundant lithic material discovered in the layer. Lithic industry is carried out in a preferential way on bajocians flints available on the slope (62%) and oxfordians flints (8%) known to approximately two kilometres. The principal characters of this industry are a frontal exploitation of core, a production of prismatic blades, many notches of Montbani type on the blades, asymmetrical trapezoids with concave truncations (of which Trapezoids of Payré), right-angled trapezoids with concave truncations, scalene triangles with flat retouches and arrows of Montclus. The analogies with Retzian (Vendée and Loire-Atlantique) are certainly numerous, but it is rather about a relationship in a vaster unit that remains to define. The non anecdotic presence of the arrows of Montclus involves the discussion on the question of the zones of contacts between Neolithic and Mesolithic of the second half of the VI^th millenium BC.     

Application d'une méthode d'analyse du territoire à partir de la situation des marqueurs graphiques à l'intérieur de la Péninsule Ibérique : le Tage International

This paper, analyses the graphic evidences of the boundaries of Tagus between Spain and Portugal from the perspective of the model defended by our team. This model proposes the existence of the relationship between graphic markers: paintings, engravings in the open air, decorations over dolmens and menhirs, understood as a compact ideological group fixed in the organization social system of European producing people and metallurgical that occupying this landscape. This argument attempt to verify the possibilities of applying a pre-defined model in an area in which have been developed investigation models, focused to study megalithic monuments, menhirs, habitational areas, paints and engravings that shows symbolic expressions of the tradition to justify the property of rich areas in natural resources in what metallurgical have a remarkable importance.     

La Réorganisation Infraciliaire au Cours de la Conjugaison et l'Origine du Primordium Buccal dans le Genre Euplotes

L'infraciliature ventrale est presque entièrement détruite lors de la conjugaison: la totalité des structures buccales, tous les cirres fronto-ventraux et transversaux, certains cirres caudaux. Le retour à l'état végétatif s'effectue en 2 étapes. Première Etape.–Différenciation d'un nouvel ensemble de cirres, dépourvu du cirre 1/I (selon la nomenclature de Wallengren); néoformation, à partir d'une ébauche située sur le territoire présomptif du cirre manquant, d'une partie des structures buccales (la moitié antérieure de la frange adorale de membranelles). Deuxième Etape.–Remplacement de tous les cirres par un nouvel ensemble comportant le cirre 1/I; différenciation des structures buccales manquantes (moitié postérieure de la frange adorale, ciliature parorale) Les rapports morphogénétiques entre le cirre 1/I et la ciliature parorale suggèrent que le territoire de ce “cirre paroral” est homologue des territoires stomatogènes d'autres Hypotriches tels que Kahliella et Stylonychia. SYNOPSIS. During conjugation of Euplotes, the ventral ciliature, including the entire oral apparatus, all the fronto-ventral and transverse cirri, and some of the caudal cirri, is nearly completely lost. As followed in silver-stained preparations, the redifferentiation of the ciliature proceeds in 2 steps. The first step entails differentiation of a new complement of cirri, except for cirrus 1/I (according to the nomenclature of Wallengren), and neoformation of the anterior part of the adoral zone of membranelles (AZM) from a primordium located in an area that would be expected to give rise to the missing 1/I cirrus. The 2nd step involves replacement of all the cirri, including 1/I, and completion of the oral apparatus by redifferentiation of the posterior half of the AZM and of the paroral ciliature. The spatial morphogenetic relationships between cirrus 1/I and the paroral ciliature suggest that the area of this “paroral cirrus” is homologous with the stomatogenic areas of other Hypotrichida, such as Kahliella and Stylonychia.     

Introduction à l’étude du site de Longgupo

The site of Longgupo, discovered in 1984, is located south of the crossing of the Three Gorges of the Yangtze, in the eastern part of Chongqing Province. Situated on the limestone slope of the Miaoyu Valley, three excavation campaigns have been carried out since 1985. The first two seasons took place from 1985–1988 and 1997–1998, directed by W.B. Huang and the last campaign from 2003–2006 by E. Boëda and Y.M. Hou. After the first two campaigns, the presence of several bones, with an estimated age of 1.9 My, notably including a mandible fragment attributed to a hominid² and the discovery of more than 20 lithic artifacts incited not only great interest in the scientific community, but controversy as well since these data contradicted diffusion models of the first hominids out of Africa. Paleoanthropological data often being privileged over other data, including lithic artifacts, the anthropic nature of the site was contested. Yet the few artifacts from the initial excavations irrefutably demonstrate their manufacture by humans, in particular those in exogenous stone. To definitively re-establish the authenticity of this site by applying the latest investigative methods, a new Franco-Chinese campaign was organized. The objective of the 2003–2006 field seasons focused on understanding and analysis of the archaeological data in their geomorphological and stratigraphic contexts.     

Révision taphonomique et techno-typologique des deux ensembles attribués au Châtelperronien de la Roche-à-Pierrot à Saint-Césaire

The Chatelperronian from la Roche-à-Pierrot in Saint-Césaire is characterized by its strong “Mousterian component”. It was discovered in a layer named Ejop, which had originally been sub-divided in two parts (Ejop SUP and Ejop INF). Up to now, the industry coming from these two sub-layers had been analyzed together without discriminating lithics discovered within the upper part from the ones discovered within the lower part. Here we present the results of our taphonomical and techno-typological analysis of the lithic industry attributed to each of the two sub-layers, including the artifacts discovered in 1993, in order to test if the strong “Mousterian component” of Ejop is shared by Ejop SUP as well as by Ejop INF. We show that the raw materials used at the site originate mostly from the local environment in both sub-layers, and that they are from a relatively low quality. Despite the small number of artifacts coming from Ejop INF, they are characteristics from a technological and typological point of view of the Mousterian, and not of the Chatelperronian. In contrast, the analyses of Ejop SUP cores show that method (volumetric blade production) and technic (marginal percussion) used are characteristic of the Chatelperronian. In Ejop SUP, scrapers still count for about half of the retouched stone-tools. Morphology and debitage technique for retouched stone-tools vary depending on the stone-tool type (end-scrapers and Chatelperron backed pieces are usually made out of blades removed with marginal percussion). Yet, it is not possible to separate within Ejop SUP two components, one Mousterian and the other one specific of the Chatelperronian, according to edge and surface damages of retouched stone-tools. We show that that Saint-Césaire Ejop layer contains two different sub-layer, a Mousterian one Ejop INF, and a Chatelperronian one, Ejop SUP. In the current state of knowledge on the site, it is not possible to decide whether the high proportion of scrapers in Ejop SUP is a testimony of retention of ancient method of production (if not ancient way of using stone-tools as hypothesized by Guilbaud et al.) or of post-depositional integration of Mousterian objects within a Chatelperronian context.     

Étude polarographique de la mobilisation du fer de la ferritine

Polarographic study of the mobilization of ferritin ironPolarographic study allows to propose a model for mobilization of ferritin iron: an equilibrium exists between iron core and small quantities of iron outside the protein.These iron atoms would be lying on electron acceptor sites including SH groups. The number of sites is dependent on iron content of ferritin.Therefore, the iron could be removed by the action of reducing agents such as xanthine oxidase or ascorbic acid, and then chelated by a complexing agent.