Search results for "Stone"
showing 10 items of 1137 documents
Interface behaviour of bonded CFRP-Calcarenite stone joints
2010
This paper presents the results of an experimental study investigating the interface behaviour between calcarenite stone and Carbon Fibre Reinforced Polymer (CFRP) reinforcement. The analysis of the results has allowed to deduce the local behaviour at the interface, which can be modelled by means of a bi-linear shear stress-slip law, according to several codes. The experimental investigation was carried out on specimens subjected to double shear pulling tests by varying the bond length of the CRFP strips. Tests enabled determination of the bond strength of the joint and the effective bond length. The parameters of the stress-slip law were calibrated on the experimental results in order to c…
Molecular phylogeny of the spider family Sparassidae with focus on the genus Eusparassus and notes on the RTA-clade and ‘Laterigradae’
2013
The phylogeny of the spider family Sparassidae is comprehensively investigated using four molecular markers (mitochondrial COI and 16S; nuclear H3 and 28S). Sparassidae was recovered as monophyletic and as most basal group within the RTA-clade. The higher-level clade Dionycha was not but monophyly of RTA-clade was supported. No affiliation of Sparassidae to other members of the 'Laterigradae' (Philodromidae, Selenopidae and Thomisidae) was observed, and the crab-like posture of this group assumed a result of convergent evolution. Only Philodromidae and Selenopidae were found members of a supported clade, but together with Salticidae and Corinnidae, while Thomisidae was nested within the hig…
Dix ans d'archéologie forestière dans le Châtillonnais (Côte-d'Or) : enclos, habitats, parcellaires
2010
National audience; Ces recherches sur les ensembles de structures de pierre sous forêt sont mises en œuvre depuis dix ans et sont inté- grées depuis 2003 dans le P.C.R. ‘Vix et son Environnement', dirigé par C. Mordant, S. Wirth et B. Chaume. Les vestiges étudiés sont implantés dans deux milieux géographiques distincts mais contigus : le plateau calcaire recouvert par la forêt domaniale de Châtillon, et les rebords de la Digeanne et du Brevon qui entaillent ce plateau à l'est et au sud. La prospection présente ici des caractères particuliers liés au couvert forestier. Les relevés G.P.S. sont intégrés dans un S.I.G. et constituent la base de cette étude, dans un va et vient…
Rod–coil copolymers from oligo(p-benzamide) foldamers
2007
Self assembling rod–coil copolymers were synthesized in which oligo(p-benzamide) rods up to the octamer were prepared via iterative solution synthesis employing the acid labile 2,4-dimethoxybenzyl amide protective group.
Light-dependent CK2-mediated phosphorylation of centrins regulates complex formation with visual G-protein.
2008
AbstractCentrins are Ca2+-binding EF-hand proteins. All four known centrin isoforms are expressed in the ciliary apparatus of photoreceptor cells. Cen1p and Cen2p bind to the visual G-protein transducin in a strictly Ca2+-dependent way, which is thought to regulate light driven movements of transducin between photoreceptor cell compartments. These relatively slow motile processes represent a novel paradigm in light adaptation of photoreceptor cells.Here we validated specific phosphorylation as a novel regulator of centrins in photoreceptors. Centrins were differentially phosphorylated during photoreceptor dark adaptation. Inhibitor treatments revealed protein kinase CK2 as the major protein…
Chronology of the oldest supracrustal sequences in the Palaeoarchaean Barberton Greenstone Belt, South Africa and Swaziland
2016
Abstract Zircon age data for felsic metavolcanic rocks of the Sandspruit and Theespruit formations, the two oldest supracrustal components in the Palaeoarchaean Barberton Greenstone Belt, show that these two successions are time-equivalent and constitute one single volcanic event at ca. 3530 Ma. The Sandspruit felsic rocks are ubiquitously metasomatized, intensely deformed and intruded by, and tectonically interlayered with, ca. 3450 Ma granitoid sills that are probably part of the Theespruit Pluton. One metasomatized Sandspruit sample contains abundant metamorphic zircons with a weighted mean 207Pb/206Pb age of 3220.1 ± 1.6 Ma, reflecting a widespread metamorphic event in parts of the east…
Sm–Nd, Rb–Sr and Pb–Pb dating of silicic carbonates from the early Archaean Barberton Greenstone Belt, South Africa
1998
Abstract Two silicic carbonate sequences occurring in the Onverwacht Group (OG) and the overlying Fig Tree Group (FTG) of the early Archaean Barberton Greenstone Belt, South Africa, contain silicified dolomites with primary structures and textures. They occur with volcanic rocks dated by single zircons. The associated Onverwacht felsic volcanics have an age of ∼3440–3416 Ma, whereas the Fig Tree volcanics are ∼3225 Ma old. Therefore, the depositional age of both sequences is between 3440 and 3225 Ma. Pb-isotopic data for different parts of a single OG whole rock sample form a linear array corresponding to a Pb–Pb age of 2632±99 Ma. Sm–Nd and Rb–Sr isotopes were analysed in four whole rock s…
Single zircon ages for felsic to intermediate rocks from the Pietersburg and Giyani greenstone belts and bordering granitoid orthogneisses, northern …
2000
Abstract Previous models for the temporal evolution of greenstone belts and surrounding granitoid gneisses in the northern Kaapvaal Craton can be revised on the basis of new single zircon ages, obtained by conventional UPb dating and PbPb evaporation. In the Pietersburg greenstone belt, zircons from a metaquartz porphyry of the Ysterberg Formation yielded an age of 2949.7±0.2 Ma, while a granite intruding the greenstones, and deformed together with them, has an age of 2853 + 19/−18 Ma. These data show felsic volcanism in this belt to have been coeval with felsic volcanism in the Murchison belt farther east, and the date of ∼2853 Ma provides an older age limit for deformation in the region…
Characterization, provenance, and tectonic setting of Fig Tree greywackes from the Archaean Barberton Greenstone Belt, South Africa
1999
Abstract In this study, mineralogical and geochemical data, as well as Sr and Nd isotopic compositions of early Archaean greywackes from the Fig Tree Group are presented to provide further information about the evolution of the Barberton Greenstone Belt (BGB) of the Kaapvaal Craton, South Africa. The chemical data on the collected greywackes from the BGB suggest limited chemical modification of the source rocks. The Eu/Eu * anomaly is negative with an average value of 0.76 which is slightly higher than that of Eu-depleted crustal rocks (0.65). High Cr and Ni concentrations and a Cr/Ni ratio of about 1.6 indicate derivation from ultramafic sources without fractionation. Although rounded zirc…
Age and evolution of a late Archean to Paleoproterozoic upper to lower crustal section in the Wutaishan/Hengshan/Fuping terrain of northern China
2005
Abstract The Taihangshan–Wutaishan area forms part of the central North China Craton and consists of three main components: the Hengshan and Fuping complexes, containing predominantly ductilely deformed late Archean to Paleoproterozoic high-grade granitoid orthogneisses, intruded by mafic dykes of gabbroic composition, and the low-grade late Archean Wutai greenstone belt, developed between the high-grade terrains and consisting of bimodal volcanic rocks and metasediments, associated with coeval granitoids. Zircon dating shows that both the Hengshan and Fuping complexes were intruded by major granitoid bodies between 2.52 and 2.48 Ga, with rare occurrences of 2.7 Ga gneisses. Wutai granitoid…