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136 results on '"Williams, C.T."'

4. In situ mapping of growth lines in the calcitic prismatic layers of mollusc shells using X-ray absorption near-edge structure (XANES) spectroscopy at the sulphur K-edge

Author

Dauphin, Y., Cuif, J.P., Doucet, J., Salome, M., Susini, J., and Williams, C.T.

Subjects
Marine biology -- Research, Sulfur -- Physiological aspects, Shells -- Growth, Shells -- Composition, Electron microscopy -- Usage, Calcite -- Physiological aspects, Magnesium -- Physiological aspects, Company growth, Biological sciences
Abstract

The microstructure and composition, including chemical speciation of sulphur (S), of two mollusc shells were investigated using a combination of scanning electron microscopy, X-ray absorption near-edge structure spectroscopy (XANES) and electron probe microanalysis (EPMA). The shell of Pinna is composed of monocrystalline, and Pinctada, of polycrystalline, calcite prisms separated by organic-rich walls. Sulphur speciation information from XANES spectra using a scanning X-ray microscope showed that the protein S content of the interprismatic walls is higher than the S[O.sup.4] content, whereas the reverse is true for the intraprismatic structures. High-spatial-resolution XANES maps for the different S species across adjacent calcite prisms confirm their distinctive distributions in the molluscan shells and illustrate the presence of narrow, submicron transverse growth features. On a larger scale, a series of wider growth zones, incorporating the submicron zones, are aligned parallel to each other and cross-cut many calcite prisms. EPMA element maps for magnesium (Mg) and S demonstrate that these growth increments are compositionally zoned, comprising alternating layers of high mineral (Mg-rich) and high organic (S-rich) components. Additionally, these maps confirm that the organic interprismatic walls have lower Mg and higher S than the intraprismatic structures.

Published
2003

5. Ventricular Assist Device Patient Phenotypes: What Attributes Describe Long Term Survival?

Author

Hariri, I.M., primary, Hannawi, B., additional, Grafton, G., additional, Nemeh, H.W., additional, Chamogeorgakis, T., additional, Lanfear, D.E., additional, Apostolou, D., additional, Selektor, Y., additional, Williams, C.T., additional, Tita, C., additional, Tanaka, D., additional, Myers, S.L., additional, Kirklin, J.K., additional, Pagani, F.D., additional, and Cowger, J.A., additional

Published
2020
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7. Hydrogen bonding effects on aspartate ester reactions

Author

Williams, C.T., Wicks, D.A., and Jarrett, W.L.

Subjects
Aspartate, Hydrogen bonding, Nuclear magnetic resonance spectroscopy, Esters, Carbonyl compounds, Monomers, Metals, metalworking and machinery industries
Abstract

Abstract Michael addition reactions were utilized to form A[B.sub.2] type monomers and esterified to form polyaspartate esters (PASPE). FTIR and NMR spectroscopic methods indicate that a relatively linear architecture was [...]

Published
2009

8. Description of a new species of Orseolia (Diptera: Cecidomyiidae) from Paspalum in West Africa, with notes on its parasitoids, ecology and relevance to natural biological control of the African rice gall midge, O. oryzivora

Author

Harris, K.M., Williams, C.T., Okhidievbie, O., LaSalle, J., and Polaszek, A.

Abstract

Field sampling of grasses growing in and near rice fields at 12 sites in Nigeria during April/May 1994 recorded the presence of galls on Paspalum scrobiculatumat densities of up to 10.9 galls per m2. These galls were induced by Orseolia bonzii Harris, sp. n., which is described. This species is morphologically close to, but distinct from, the African rice gall midge, Orseolia oryzivora Harris & Gagné, with which it has been confused in earlier studies of that pest species. In host-transfer experiments O. bonzii did not transfer to rice, Oryza sativa. Six hymenopterous parasitoids were reared from galls of O. bonzii and the most abundant of these were Platygaster diplosisae Risbec, Aprostocetus nr. procerae (Risbec) and Neanastatusnr. cinctiventris Girault. Host-transfer experiments with the Platygasterand Aprostocetus species from O. bonzii on Paspalum indicated that the Platygaster may not transfer onto O. oryzivora on rice whereas the Aprostocetus does. The overlap between the parasitoid faunas of the two species of Orseolia is potentially useful as it may be possible to enhance the natural biological control of O. oryzivora by manipulating parasitoid populations on Paspalum

Published
2017

9. The host range, annual cycle and parasitoids of the African rice gall midge Orseolia oryzivora (Diptera: Cecidomyiidae) in central and southeast Nigeria

Author

Williams, C.T., Okhidievbie, O., Harris, K.M., Ukwungwu, M.N., Williams, C.T., Okhidievbie, O., Harris, K.M., and Ukwungwu, M.N.

Abstract

Host range experiments and field sampling in Nigeria produced no evidence that African rice gall midge, Orseolia oryzivora Harris - Gagné, can develop on plants other than Oryza species. Sampling in three outbreak areas during 1994 showed that the insect's annual cycle varied according to the agroecological zone and rice cropping pattern. In the humid forest zone, Orseolia oryzivora persisted through the short dry season on ratoons of cultivated rice Oryza sativa at a rainfed site and on dry season rice crops at an irrigated one. In contrast, at rainfed sites in the moist savannah zone the pest survived the longer dry season on the perennial wild rice O. longistaminata, while ratoons and volunteers of O. sativa provided 'bridges' between the wild host and wet season rice crops. Early in the wet season at rainfed sites, galls of Orseolia oryzivora were not found at high density on wild rice, ratoons or volunteers. The heavy infestations which developed by October resulted primarily from rapid multiplication on rice crops themselves during the wet season. At all 13 sites sampled, the large majority of galls were found on fallow or cropped rice fields, rather than in ditches, bunds or uncultivated wetland, irrespective of the time of year or the hosts involved. From gall dissections, the parasitoids Aprostocetus procerae (Risbec) and Platygaster diplosisae Risbec caused over 30% mortality at some sites by October but generally increased too late to prevent crop damage. Implications of the results for the management of Orseolia oryzivora are discussed

Published
2017

12. Drive Line Infections Are Not Associated with an Increased Incidence of Thromboembolic Complications in Patients on Continuous Flow LVAD Support

Author

Xuereb, L., primary, Kaur, B., additional, Akrawe, S., additional, Rashty, J., additional, Nemeh, H.W., additional, Borgi, J., additional, Tita, C., additional, Selektor, Y., additional, Velez, M., additional, Lanfear, D.E., additional, Williams, C.T., additional, Paone, G., additional, and Morgan, J.A., additional

Published
2016
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14. Couches coquillières de l'huître perlière Pinctada margaritifera : correspondance entre microstructure et composition

Author

Farre, B., Brunelle, A., Laprévote, O., Cuif, J.P., Williams, C.T., Dauphin, Y., Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Substances Naturelles (ICSN), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Dpt of Mineral & Palaeontology, and The Natural History Museum

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Published
2011

15. Biomineralization in Mollusc shells

Author

Dauphin, Y., Cuif, J.P., Salomé, M., Williams, C.T., Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), Dpt of Mineral & Palaeontology, and The Natural History Museum

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

16. Caractéristiques chimiques et structurales de l'aragonite biogénique

Author

Farre, B., Dauphin, Y., Meibom, A., Salome, M., Williams, C.T, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Published
2008

17. Distribution of chemical components in coral skeletons provides evidence for an overall control of crystallization at a submicrometer scale

Author

Baronnet, Alain, Cuif, J.P., Dauphin, Y., Farre, B., Williams, C.T., Université Paul Cézanne - Aix-Marseille 3, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

18. Microstructures and compositions of multilayered shells of Haliotis (Mollusca, Gastropoda). Biomineralization: from paleontology to materials science

Author

Dauphin, Y., Williams, C.T., Salomé, M., Susini, J., Cuif, J.P., Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Edi. Univ. Santiago (Chile)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

19. Co-existence of calcite and aragonite in Cretaceous belemnite rostra

Author

Dauphin, Y., Williams, C.T., Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Published
2007

20. Nanostructures of the calcitic and aragonitic crystals of the pearl oyster shells and distribution of their mineralizing matrices

Author

Farre, B., Meibom, A., Salomé, M., Williams, C.T., Dauphin, Y., Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and CRINON, Evelyne

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

Geophysical Research Abstracts, 9, 01643, 1607-7962/gra/EGU2007-A-01643

Published
2007

21. Aragonitic rostra of the Turonian belemnitid Goniocamax : arguments from diagenesis

Author

Dauphin, Y., Williams, C.T., Barkskov, I.-S., Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and CRINON, Evelyne

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

22. The chemical compositions of dentine and enamel from recent reptile and mammal teeth –variability in the diagenetic changes of fossil teeth

Author

Dauphin, Y., Williams, C.T., CRINON, Evelyne, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

24. Critères de validité des informations paléoenvironnementales : distribution des phases organiques minéralisantes et préservation des nanostructures

Author

Blamart, D., Cuif, J.P., Dauphin, Y., Rollion-Bard, C., Salomé, M., Susini, J., Williams, C.T., CRINON, Evelyne, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2006

25. Microstructures and chemical composition of giant avian eggshells

Author

Dauphin, Y., Cuif, J.P., Salomé, M., Susini, J., Williams, C.T., Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and CRINON, Evelyne

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2006

26. Microstructure et composition des tests de Mollusques : le cas du gastéropode Haliotis

Author

Dauphin, Y., Cuif, J.P., Williams, C.T., Salomé, M., Susini, J., CRINON, Evelyne, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Published
2006

27. Modifications diagénétiques et biais induits dans les reconstitutions paléoenvironnementales basées sur les dents de vertébrés

Author

Dauphin, Y., Williams, C.T., Quantin, Cécile, Massard, P., CRINON, Evelyne, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Published
2006

28. Comparative diagenesis of fossile reptile and mammal teeth

Author

Dauphin, Y., Williams, C.T, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

p. 16 & poster

Published
2005

29. Assessing the structural and compositional changes in ancient biogenic Ca-carbonates : the aragonite skeletons of Triassic corals as a case-study of measurement reliability

Author

Cuif, J.P., Blamart, D., Dauphin, Y., Meibom, A., Rollion-Bard, C., Salomé, M., Susini, J., Williams, C.T, CRINON, Evelyne, Interactions et dynamique des environnements de surface (IDES), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2005

41. Testing palaeo-environmental proxies in Jurassic belemnites: Mg/Ca, Sr/Ca, Na/Ca, delta 18O and delta 13C

Author

McArthur, J.M., Doyle, P., Leng, Melanie, Reeves, K., Williams, C.T., Garcia-Sanchez, R., Howarth, R.J., McArthur, J.M., Doyle, P., Leng, Melanie, Reeves, K., Williams, C.T., Garcia-Sanchez, R., and Howarth, R.J.

Abstract

We test the hypothesis that the noise in belemnite records through time results from changing climate. We do so by comparing palaeo-proxies (Mg/Ca, Sr/Ca, Na/Ca, δ18O, δ13C) in two species of Toarcian belemnites, Acrocoelites (Odontobelus) vulgaris (14 specimens) and Acrocoelites (Acrocoelites) subtenuis (10 specimens), deposited in a period of time that was short relative to the timescale of climate change. The specimens are interpreted to have been regurgitated from the stomach of a marine predator and so were deposited together in a geological instant of Early Jurassic time. In A. (O.) vulgaris, isotopic and elemental palaeo-proxies group tightly, suggesting that this belemnite occupied a restricted environmental niche. In A. (A.) subtenuis, elemental and isotopic compositions spread more widely, suggesting that this species occupied a greater range of habitats. Possible sexual dimorphism in A. (O.) vulgaris is reflected in bimodal Mg/Ca and differing intra-rostral distribution of Mg in putative dimorphs; concentrations decline by 30% from apical line to rim in specimens with high Mg/Ca, but are largely invariant radially in specimens with lower Mg/Ca. Sexual dimorphism in A. (A.) subtenuis yields a bimodality in size, Mg/Ca, and intra-rostral distribution of Mg; larger specimens have a higher Mg/Ca, and Mg concentrations that increase along radial traverses from apical line to rim, whilst the smaller specimens show a mid-rostral minimum in Mg concentration. Radial profiles of concentrations for Sr and Na vary little in all forms. Toarcian belemnites of these species thus show strong biofractionation effects on Mg/Ca, and little or no observable biofractionation of Sr/Ca or Na/Ca. It follows that much of the noise in belemnite records results from biofractionation, and from a cosmopolitan life-style of some belemnite species, rather than climate-change. For Toarcian belemnites, we suggest that Sr/Ca is the best indicator of palaeo-temperature.

Published
2007

42. Incorporation of REE into leucophanite:a compositional and structural study

Author

Mortensen, Henrik Friis, Balic Zunic, Tonci, Williams, C.T., Garcia-Sanchez, R., Mortensen, Henrik Friis, Balic Zunic, Tonci, Williams, C.T., and Garcia-Sanchez, R.

Abstract

The crystal structures of nine, and the chemical compositions of ten, natural samples of leucophanite, ideally NaCaBeSi2O6F, were investigated. The analysed samples display a large compositional variation with trace-element abundances >50,000 ppm, primarily due to rare earth elements (REE). Fromthese data, we propose a substitution scheme for the incorporation of REE for Ca, with additional Na substituting for Ca and the generation of vacancies to ensure charge balance. Compositional zonation was observed in some samples; this zonation correlates with variations in cathodoluminescence. The crystal structure of the nine analysed samples could all be refined in space group P212121. We found no evidence for a reduction of symmetry with increased trace-element concentration. Various twin combinations were observed and these seem related to crystallization conditions rather than structural or chemical factors.

Published
2007

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