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Search Results: 1 - 10 of 3941 matches for " Odin Gilles Serge "
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Description et illustration de quarante-quatre gilianelles (microproblematica) et de dix autres microproblematica du Crétacé de la coupe stratotypique de Tercis (limite Campanien-Maastrichtien), Sud-Ouest France [Description and illustration of forty-four gilianelles (microproblematica) and ten other microproblematica of the Cretaceous of the stratotype section at Tercis (Campanian-Maastrichtian boundary), South-West France]
Odin Gilles Serge
Carnets de Géologie , 2008,
Abstract: L'étude des microfossiles extraits par acétolyse des niveaux carbonatés indurés de la série campano-maastrichtienne du stratotype de limite à Tercis (Landes, France) a permis de découvrir 44 taxons attribués au groupe des gilianelles (microproblematica appartenant probablement aux Protistes, Protozoaires, Rhizopodes) ainsi que dix autres microproblematica. 281 vues au microscope électronique et 183 vues au microscope optique permettent d'illustrer, chez les gilianelles, 36 espèces, et 8 sous-espèces appartenant à 15 genres dont 14 nouveaux. Les nouveaux genres sont : Tercensella, Azymella, Numismella, Aturella, Scutellella, Corniculum, Caccabella, Orculiella, Pennigerella, Corbella, Aquilegiella, Pocillella, Coraliella, Obbella. Chez les autres microproblematica, neuf espèces et une sous-espèce sont proposées appartenant à sept genres nouveaux : Globulella, Piperella, Vasculum, Lucernellus, Cimicellus, Tubella, Pilella. Cette première revue d'ensemble avec identification des taxons a conduit à caractériser précisément un groupe dont l'identité et la cohérence sont établies d'après les caractères morphologiques du corps des tests et des expansions qu'ils portent et leur ornementation. Ces critères, utilisés de fa on ordonnée permettent de proposer un classement rationnel qui pourra être confirmé par d'autres observations pour devenir une classification. L'étude de la répartition stratigraphique indique qu'ils constituent un remarquable outil de datation relative dans le site stratotypique et son voisinage immédiat où ils permettent d'individualiser des intervalles de dép t de l'ordre de 0,1 Ma, plus fins que la plupart de ceux obtenus d'après les nombreux groupes de microfossiles ou de macrofossiles classiques étudiés pour qualifier ce stratotype. Le repérage de la limite Campanien-Maastrichtien peut se faire grace à la lignée des aturelles ; elle se situe au début de la zone d'existence de l'aturelle édentée (Aturella edentula).Following acetolysis, microproblematica were collected from indurated carbonates sampled from the stratotype section of the Campanian-Maastrichtian boundary at Tercis (Landes, France). 44 taxa of the gilianelles group (microproblematica probably pertaining to the Protista, Protozoans, Rhizopods) as well as ten other microproblematica were discriminated. To document the taxa in this paper 281 scanning electronic microscope images and 183 optical microscope images are presented. The gilianelles encompass 36 species, and 8 subspecies referred to 15 genera of which 14 are new. The new genera are: Tercensella, Azymella, Numismella, Atu
Traces de volcanisme explosif dans le Campanien pyrénéen aux alentours du stratotype de limite Campanien-Maastrichtien à Tercis (SO France, N Espagne). Repérage biostratigraphique avec une étude particulière du foraminifère Radotruncana calcarata [Traces of explosive volcanism in the Pyrenean Campanian around the Campanian-Maastrichtian boundary type section at Tercis (SW France, N Spain). Biostratigraphy with emphasis on the foraminifer Radotruncana calcarata]
Odin Gilles Serge
Carnets de Géologie , 2010,
Abstract: Pyroclastic material including idiomorphic crystals of sanidine, biotite, and apatite, first identified in the type section at Tercis are contemporaneous with the Radotruncana calcarata (planktonic foraminifer) total range zone. A search was undertaken to define the palaeogeographical extent and to determine the importance of these remains of a previously unknown Campanian regional alkaline volcanic episode. A preliminary biostratigraphical search was carried out in the Tercis area and in the western Pyrenees followed by detailed micropalaeontological studies in southwestern France and northern Spain. The findings from five upper Campanian platform and flysch facies are reported in detail and deductions from three others are summarized. First, The microfaunal count of the boundary stratotype at Tercis has been increased by the use of acetolytic techniques to disaggregate indurated carbonates. So isolated tests of some key biostratigraphic markers are documented for the first time. The paucity in specimens of Radotruncana calcarata previously seen in thin sections from the type outcrop is not due to a scarcity of this particular taxon but to a general dearth of globotruncanids in the platform facies deposits of the Aturian Basin. The study shows that acetolysis multiplies the power of investigation of indurated limestones. Thus, the abundance and diversity of microproblematica discovered and studied in the stratotype section since 2006 has been confirmed and two new forms of incertae sedis are reported, one of which is called here Velafer ovatus. Today, 70 species of microproblematica are recognized at Tercis. These microproblematica allow a chronologic calibration of the deposits like or even more precise than those obtainable using ammonites or planktonic foraminifers. Sections sampled in the western Pyrenean flysch facies include the stratigraphic interval comprising the total range zone of Rd. calcarata for which we suggest here a duration of 0.80 ±0.05 Ma. No microproblematica were found in these deep detrital facies. All sections reaching the Campanian-Maastrichtian boundary contain a Contusotruncana (foraminifer) of which the morphology, illustrated anew from 3 discrete sections, is consistent with that of the specimens identified at this level in the Tercis type-section; they were called C. contusa or C. contusa?/C. patelliformis? These micropalaeontological studies substantiate the choice of Tercis as the best section in the world for location of the stratotype of the Campanian-Maastrichtian stage boundary; they show again its striking regional a
Nouvelles études micropaléontologiques sur le stratotype de la limite Campanien-Maastrichtien à Tercis (SO France) : compléments sur les ostracodes extraits par acétolyse
Andreu Bernard,Odin Gilles Serge
Carnets de Géologie , 2008,
Abstract: Une nouvelle étude de la microfaune, obtenue par acétolyse des niveaux indurés dans le Campanien-Maastrichtien de la carrière de Tercis, a permis de récolter 22 espèces additionnelles au regard de l'étude publiée en 2001 et de porter ainsi à 75 espèces, réparties sur 34 genres reconnus et 4 indéterminés, la biodiversité en ostracodes de ce site. Des espèces de petite taille, généralement rares, rapportées aux genres Aversovalva, Bythoceratina et Eucytherura ont par ailleurs été recueillies. Les associations de genres et d'espèces d'ostracodes sont caractéristiques du Campanien-Maastrichtien, dans un environnement de plate-forme carbonatée ouverte.
Nouvelles études micropaléontologiques sur le stratotype de la limite Campanien-Maastrichtien à Tercis (SO France) : les gilianelles (microproblematica) extraites par acétolyse [New micropalaeontological studies on the stratotype of the Campanian-Maastrichtian boundary at Tercis (SW France): the gilianelles (microproblematica) extracted through acetolysis]
Odin Gilles Serge,Lethiers Alexandre
Carnets de Géologie , 2006,
Abstract: The Campanian-Maastrichtian stratotype section at Tercis (SW France) consists mainly of hard calcareous levels. Their treatment using acetolysis left residues among which for the first time well-preserved free microfossils were obtained (These levels had been studied previously only through thin sections). Within these residues, a wealth of calcareous shells of unknown affinity (incertae sedis) occur. These previously undescribed fossils are documented herein with photographs and drawings. Optical observations are synthesised in computer assisted drawings which depict 36 discrete forms. Scanning electron microscopy documented the nannostructures of these tests which led to the recognition of 30 forms with a common organisation and nannostructure. These are the microproblematica group called "gilianelles". The remaining six forms of incertae sedis do not share the same characteristics. According to morphological observations, a planktonic existence is inferred for most of the incertae sedis. The simple organisation and small size of the gilianelles suggest that they may represent a new Order of Rhizopod Protozoans. Their stratigraphical distribution has been established in the stratotype section of the "Grande Carrière" at Tercis (SW France). This distribution shows an extraordinary rate of turn-over with some taxa having a range of less than 1 Ma.
New micropalaeontological studies on the type section of the Campanian-Maastrichtian at Tercis (SW France): new ostracodes obtained using acetolysis
Andreu Bernard,Odin Gilles Serge
Carnets de Géologie , 2008,
Abstract: Through the use of acetolysis new micropalaeontological studies on the type section of the Campanian-Maastrichtian boundary at Tercis (SW France) we obtained additional information on ostracodes. Acetolysis on hard carbonates levels of the Tercis quarry found 22 species in addition to those of the studies published in 2001. Today, 75 species are recognized: they represent 34 known genera, and 4 currently unidentified. Small species usually rare of the genera Aversovalva, Bythoceratina and Eucytherura were collected. All of the assemblages (of both genera and species) are characteristic of a Campanian-Maastrichtian open carbonate platform environment.
Stage boundaries, global stratigraphy, and the time scale: towards a simplification
Odin Gilles Serge,Gardin Silvia,Robaszynski Francis,Thierry Jacques
Carnets de Géologie , 2004,
Abstract: This paper examines four facets of stratigraphic terminology and usage considered faulty and proposes corrective measures. The four perfectible areas are: (1) The system of dual nomenclature requiring discrete terminologies for the superpositional and temporal aspects of rock units. (2) The premise that a GSSP establishes the base of a stage as being coincident with the top of the preceding stage rather than simply defining it as the boundary between stages. (3) The rejection of supplementary (auxiliary) sections that would broaden the knowledge of a GSSP and enlarge the area in which it is easily usable. (4) The current dual system of nomenclature for Precambrian and Phanerozoic strata is accepted, but a third system is proposed for strata formed in the last 3 to 5 Ma. In addition, the paper advocates a broader use of a limited number of conventions but warns against their proliferation; units shortened thereby would be more difficult to recognize. It points out the clear distinction between these conventions - a matter of administration and general compliance - and knowledge - a domain where free expression of opinion is indispensable -.
The Universal Review (1888-1890): Transformative Processes in Late-Victorian Journal Publishing
Odin Dekkers
TS·> Tijdschrift voor Tijdschrift-studies , 2011,
Abstract: De Universal Review (1888-1890) was een ambitieuze poging om een deel van de laat-Victoriaanse tijd-schriftenmarkt aan te boren door binnen het genre van de review een aantal innovaties in te voeren. De drijvende kracht achter het tijdschrift was Harry Quilter (1851-1907), schilder, journalist en fanatiek pleitbezorger van de eerste generatie prerafa litische kunstenaars. Quilter had geen enkele ervaring op het gebied van tijdschriftredactie, maar dat weerhield hem er niet van om uit eigen middelen een duur en rijkelijk ge llustreerd tijdschrift te starten dat, in tegenstelling tot de concurrentie, geen specifieke politieke of religieuze agenda had. Hij slaagde erin een groot aantal contribuanten van naam en uiteenlopende signatuur bij het tijdschrift te betrekken, waaronder inmiddels gecanoniseerde auteurs als Alphonse Daudet, Henry James, Leo Tolstoi en Guy de Maupassant. Het tijdschrift werd aanvankelijk gunstig ontvangen; er was met name veel lof voor de kwaliteit van de illustraties. Ondanks het grote aantal bijdragen van hoge kwaliteit kwam het einde van de Universal Review toch al snel in zicht. Dit artikel beoogt niet zozeer een analyse van de inhoud van het tijdschrift te geven, als wel van het samenspel van factoren dat leidde tot de ondergang van dit nog niet eerder onderzochte periodiek, mede in een poging meer zicht te krijgen op een aantal veranderingsprocessen die de tijdschriftenwereld in Engeland op dat moment onderging.
Pistes forestières et imaginaire
Gilles Couix,Corinne Lafay,Marie-Serge Lebon
Mappemonde , 1990,
Abstract: L'utilisation de chorèmes comme d'un alphabet susceptible de traduire des concepts, permet de proposer une représentation de l'imaginaire, celle de la forêt mythique de Bretagne, et de la confronter à celle de la réalité, la forêt bretonne actuelle.
The TCL1A Oncoprotein Interacts Directly with the NF-κB Inhibitor IκB
Virginie Ropars, Gilles Despouy, Marc-Henri Stern, Serge Benichou, Christian Roumestand, Stefan T. Arold
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006567
Abstract: The T cell leukaemia/lymphoma 1A (TCL1A) oncoprotein plays key roles in several B and T cell malignancies. Lacking enzymatic activity, TCL1A's transforming action was linked to its capacity to co-activate the protein kinase AKT via binding to its pleckstrin homology (PH) domain. However, perturbation of AKT signalling alone was recently shown insufficient to explain TCL1A oncogenesis, suggesting that TCL1A has additional cellular partners. Searching for such additional targets, we found that TCL1A binds specifically and directly to the ankyrin domain of IκB, the inhibitor of the NF-κB transcription factors. Through binding assays and a structural analysis by small angle X-ray scattering, we show that TCL1A and IκB interact in yeast-two-hybrid systems, when transiently overexpressed in 293 cells, and as recombinant proteins in vitro. We further establish that the association between TCL1A and IκB is compatible with AKT binding to TCL1A, but incompatible with IκB binding to NF-κB. By interfering with the inhibition of NF-κB by IκB, TCL1A may increase the concentration of free NF-κB molecules sufficiently to trigger expression of anti-apoptotic genes. Thus our data suggest an additional route by which TCL1A might cause cancer.
Cinnamaldehyde and cinnamaldehyde derivatives reduce virulence in Vibrio spp. by decreasing the DNA-binding activity of the quorum sensing response regulator LuxR
Gilles Brackman, Tom Defoirdt, Carol Miyamoto, Peter Bossier, Serge Van Calenbergh, Hans Nelis, Tom Coenye
BMC Microbiology , 2008, DOI: 10.1186/1471-2180-8-149
Abstract: Our results indicate that cinnamaldehyde and several substituted derivatives interfere with AI-2 based QS without inhibiting bacterial growth. The active compounds neither interfered with the bioluminescence system as such, nor with the production of AI-2. Study of the effect in various mutants suggested that the target protein is LuxR. Mobility shift assays revealed a decreased DNA-binding ability of LuxR. The compounds were further shown to (i) inhibit biofilm formation in several Vibrio spp., (ii) result in a reduced ability to survive starvation and antibiotic treatment, (iii) reduce pigment and protease production in Vibrio anguillarum and (iv) protect gnotobiotic Artemia shrimp against virulent Vibrio harveyi BB120.Cinnamaldehyde and cinnamaldehyde derivatives interfere with AI-2 based QS in various Vibrio spp. by decreasing the DNA-binding ability of LuxR. The use of these compounds resulted in several marked phenotypic changes, including reduced virulence and increased susceptibility to stress. Since inhibitors of AI-2 based quorum sensing are rare, and considering the role of AI-2 in several processes these compounds may be useful leads towards antipathogenic drugs.Vibriosis, caused by Vibrio spp., is a major disease of marine fish and shellfish and is an important cause of economic loss in aquaculture [1,2]. Until recently prophylactic antibiotics were extensively used in aquaculture [3,4]. However, overuse of antibiotics resulted in increased rates of resistance so that novel approaches are required to manage vibriosis [5]. A possible novel target is the bacterial communication system. Bacteria monitor their population densities through the production and sensing of small signal molecules called autoinducers, a process entitled as quorum sensing (QS). To date three types of QS systems have been identified in Vibrio spp. [6]. Acylated homoserine lactones (AHL) are used as signal molecules in the LuxM/N QS system [7], while in the CqsA/S system, (S)-3-hydro
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