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See detailGlacial-interglacial rain ratio variations: effect on atmospheric CO2 levels and sedimentary carbonate preservation/dissolution processes
Munhoven, Guy ULg

Conference (2006, February 10)

A reduction of the carbonate-carbon to organic-carbon export rain ratio during glacial times is commonly advanced to explain an important part of the observed glacial-interglacial atmospheric CO2 ... [more ▼]

A reduction of the carbonate-carbon to organic-carbon export rain ratio during glacial times is commonly advanced to explain an important part of the observed glacial-interglacial atmospheric CO2 variation. This hypothesis was tested and side-effects on the evolution of carbonate preservation/dissolution in the surface sediment explored with a multi-box model (MBM) of the ocean carbon cycle, fully coupled to a new transient advection-diffusion-reaction model (called MEDUSA) representing early diagenesis processes of carbonate minerals in the surface sediment. MEDUSA explicitly considers the role of organic matter remineralisation in the sediment column to enhance calcite (and aragonite) dissolution. It is fully bi-directional and takes chemical erosion into account in times when carbonate dissolution makes the sediment mixed-layer collapse faster than the sediment supply to the surface is able to counterbalance. Coupled model experiments were run for 240,000 years, forced by variable sea-level, temperature and salinity histories, and variable continental weathering inputs. Various scenarios for the evolution of the rain ratio over glacial to interglacial periods were adopted. A peak reduction of the rain ratio by 40% at the Last Glacial Maximum (LGM) was found to produce a net atmospheric pCO2 reduction of about 30ppm, on top of a 60ppm reduction produced by changing continental shelf carbonate accumulation and changing continental weathering inputs. The overall 90ppm oscillation compares well with the observed data. However, the effect on the model sedimentary record is clearly at odds with actual sediment records. The changes related to continental shelf processes and variable weathering flux depress the calcite saturation horizon by about 1km at the LGM; if rain ratio variations are also considered, that depression increases by another km. An assessment of the respective contributions from various model parameters will be presented. [less ▲]

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See detailGlacial-interglacial variability of atmospheric CO2 due to changing continental silicate rock weathering: A model study
Munhoven, Guy ULg; Francois, Louis ULg

in Journal of Geophysical Research (1996), 101(D16), 21423-21437

An 11-box model of the oceanic carbon cycle including sedimentary processes is used to explore the role chemical weathering of continental silicate rocks might play in driving atmospheric CO2 levels on ... [more ▼]

An 11-box model of the oceanic carbon cycle including sedimentary processes is used to explore the role chemical weathering of continental silicate rocks might play in driving atmospheric CO2 levels on glacial-interglacial timescales. Histories for the consumption of CO2 by silicate rock weathering processes are derived from the marine Ge/Si record. Taking the major uncertainties in the knowledge of the Ge and Si cycles into account, several histories for the evolution of the riverine dissolved silica fluxes are calculated from this record. The investigation of the systematics between riverine dissolved silica and bicarbonate fluxes under different weathering regimes leads us to the tentative conclusion that although there is no correlation between dissolved silica and total bicarbonate concentrations in the major rivers, there may exist a negative correlation between weathering intensity and the ratio of dissolved silica to bicarbonate derived from silicate weathering alone. With this correlation as a working hypothesis, it is possible to interpret the dissolved silica fluxes in terms of equivalent CO2 consumption rates. The calculated histories indicate that glacial rates of CO2 consumption by chemical silicate rock weathering could have been twice, and possibly up to 3.5 times, as high as they are today. When used to force the carbon cycle model, they are responsible for glacial-interglacial pCO2 variations in the atmosphere of typically 50–60 ppm and up to 95–110 ppm. These variations are superimposed to a basic oscillation of 60 ppm generated by the model, mainly in response to coral reef buildup and erosion processes. The total pCO2 signal has an amplitude of about 80–90 ppm and up to 125–135 ppm. Although these large amplitudes indicate that silicate weathering processes should be taken into account when studying glacial-interglacial changes of CO2 in the atmosphere, it also raises new problems, such as too high CO2 levels during the period from 110–70 kyr B.P., requiring further study. [less ▲]

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See detailGlacial/interglacial instabilities of the Western Boundary Under Current during the last 365 kyr from Sm/Nd ratios of the sedimentary clay-size fractions at ODP site 646 (Labrador Sea)
Fagel, Nathalie ULg; Hillaire-Marcel, Claude ULg

in Marine Geology (2006), 232(1-2), 87-99

We present 40 Sm-Nd isotope measurements of the clay-size (< 2 mu m) fractions of sediments from the Southern Greenland rise (ODP-646) that span the last 365 kyr. These data track changes in the relative ... [more ▼]

We present 40 Sm-Nd isotope measurements of the clay-size (< 2 mu m) fractions of sediments from the Southern Greenland rise (ODP-646) that span the last 365 kyr. These data track changes in the relative supply of fine particles carried into the deep Labrador Sea by the Western Boundary Under Current (WBUC) back to the fourth glacial-interglacial cycles. Earlier studies revealed three general sources of particles to the core site: (i) Precambrian crustal material from Canada, Greenland, and/or Scandinavia (North American Shield-NAS), (ii) Palaeozoic or younger crustal material from East Greenland, NW Europe, and/or western Scandinavia (Young Crust-YQ and (iii) volcanic material from Iceland and the Mid-Atlantic Ridge (MAR). Clay-size fractions from glacial sediments have the lowest Nd isotopic ratios. Supplies of young crustal particles were similar during glacial oxygen isotope stages (OIS) 2, 6, and 10. In contrast the mean volcanic contributions decreased relative to old craton material from OIS 10 to OIS 6 and then from OIS 6 to OIS 2. The glacial OIS 8 interval displays a mean Sm/Nd ratio similar to those of interglacials OIS 1, 5, and 9. Compared with other interglacials, OIS 7 was marked by a higher YC contribution but a similar similar to 30% MAR supply. The overall NAS contribution dropped by a factor of 2 during each glacial/interglacial transition, with the MAR contribution broadly replacing it during interglacials. To decipher between higher supplies and/or dilution, particle fluxes from each end member were estimated. Glacial NAS fluxes were systematically higher than interglacial fluxes. During the time interval examined, fine particle supplies to the Labrador Sea were strongly controlled by proximal ice-margin erosion and thus echoed the glacial stage intensity. In contrast, the WBUC-carried MAR supplies from the eastern basins did not change significantly throughout the last 365 kyr, except for a marked increase in surface-sediments that suggests unique modem conditions. Distal WBUC-controlled inputs from the Northern and NE North Atlantic seem to have been less variable than proximal supplies linked with glacial erosion rate. (c) 2006 Elsevier B.V All rights reserved. [less ▲]

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See detailGlacial–interglacial rain ratio changes: Implications for atmospheric CO2 and ocean–sediment interaction
Munhoven, Guy ULg

in Deep-Sea Research Part II, Topical Studies in Oceanography (2007), 54(5-7), 722-746

A reduction of the carbonate-carbon to organic-carbon export rain ratio during glacial times has been advanced to explain the glacial–interglacial atmospheric CO2 variations. This hypothesis is tested and ... [more ▼]

A reduction of the carbonate-carbon to organic-carbon export rain ratio during glacial times has been advanced to explain the glacial–interglacial atmospheric CO2 variations. This hypothesis is tested and implications for the dynamics of sedimentary carbonate preservation and dissolution are explored with a multi-box model (MBM) of the ocean carbon cycle, fully coupled to a new transient early diagenesis model (called MEDUSA). A peak reduction of the rain ratio by 40% at the Last Glacial Maximum (LGM) was found to produce a net atmospheric pCO2 reduction of about 40 ppm. Changing shelf carbonate accumulation rates and continental weathering inputs produced a 55–60 ppm reduction. The combination of the two mechanisms generates a pCO2 change of 90–95 ppm, which compares well with the observed data. However, the resulting model sedimentary record does not conform to actual sedimentary records. The changes related to continental shelf processes and variable weathering flux depress the calcite saturation horizon (CSH) by about 1 km at the LGM; if rain ratio variations are also considered, that depression increases by another km. In addition to this large amplitude for the CSH, possibly due to the adopted box-model approach, the changing rain ratio also leads to transition zone changes in the model sedimentary record that are opposite in phase with data-based reconstructions. Realistic changes in the aragonite fraction of the carbonate rain were found to have only a minimal impact on atmospheric pCO2. Finally, chemical erosion of deep-sea sediment was shown to reduce the amplitude of variation of the sedimentary CCD by about 10–20%. It may provide a mechanism to improve the model-data agreement. [less ▲]

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See detailGlageon: une coupe du Givetien en Avesnois (France). Sédimentologie, Coraux, géologie régionale, diagenèse
Boulvain, Frédéric ULg; Coen-Aubert, M.; Mansy, J. L. et al

in Bulletin de la Société Belge de Géologie (1995), 103(1-2), 171-203

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See detailA glance on characterization of almond kernels from five varieties cultivated in eastern Morocco
Houmy, Nadia; Abid, M.; Addi, M. et al

Poster (2016, February 05)

The Green Morocco Plan is established for 2008-2020 to improve productivity in the agriculture sector and to plant more productive perennial tree crops such as almonds that are better suited for Morocco's ... [more ▼]

The Green Morocco Plan is established for 2008-2020 to improve productivity in the agriculture sector and to plant more productive perennial tree crops such as almonds that are better suited for Morocco's climate. Belgian Development Agency support almond orchards extension in eastern Morocco in purpose to achieve socio-economic improvement. This research is part of a local project (PROFAO) for development of almond in eastern Morocco. The present study evaluates some almond oil parameters fiber and protein content of five almond varieties (Beldi, Fournat, Ferraduel/Ferragnes and Marcona). The aim is to classify varieties on the basis of kernels content of oil and their richness of fibers. Significant variations were found among the five almond varieties examined. Almond oil content ranged from 48 % for Fournat to aproximativly 60 % for Marcona & Beldi. Fatty acids (FA) profiles are slightly different. Oleic acid ranged from 58 % for Marcona to 68 % for Beldi; linoleic acid ranged from 20 % for Beldi to 30 % for Marcona. Saturated FA (palmitic and stearic) were found at levels lesser than 10 %. In almond press cake, total protein content varied between 55 % for Beldi and 48 % for Fournat. The highest total fiber content was found for Fournat (25 %), however Beldi present the lowest rate (16 %). We conclude that Marcona & Beldi would be interesting varieties for almond oil; Fournat seems to be interesting for its richness in fiber. [less ▲]

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See detailGlance on preliminary nutritional data ORISCAV-LUX Survey
Alkerwi; Guillaume, Michèle ULg

Conference (2009)

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See detailGlances at the EC Nitrate Directive implementation in the Walloon Region of Belgium
Marcoen, Jean Marie ULg

Scientific conference (2006, July 04)

Detailed reference viewed: 27 (4 ULg)
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See detailThe Glasgow Coma Scale: time for critical reappraisal?
Laureys, Steven ULg; Bodart, Olivier ULg; Gosseries, Olivia ULg

in Lancet Neurology (2014), Vol 13

Detailed reference viewed: 36 (4 ULg)
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See detailGlass eel swimming behaviour during their estuarine migration: new insights from video tracking analysis
Delcourt, Johann ULg; bolliet, Valérie; Ylieff, Marc ULg et al

Conference (2010, July)

Detailed reference viewed: 71 (8 ULg)
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See detailGlass production in late antiquity
Van Wersch, Line ULg; Mathis, François ULg; Dupuis, Thomas ULg et al

Poster (2009)

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See detailGlass production in Merovingian time
Van Wersch, Line ULg; Mathis, François ULg; Othmane, G. et al

Poster (2010, May)

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See detailGlass transition phenomena applied to powdered amorphous food carbohydrates
Ronkart, Sebastien N; Blecker, Christophe ULg; Deroanne, Claude et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2009), 13(1), 177-186

Glass transition phenomena applied to powdered amorphous food carbohydrates. During these last fifteen years, some food technologists and scientists have become aware of the importance of the glass ... [more ▼]

Glass transition phenomena applied to powdered amorphous food carbohydrates. During these last fifteen years, some food technologists and scientists have become aware of the importance of the glass transition, a thermal property of glassy or amorphous material, in food preparation processes. Recent studies have successfully correlated this fundamental notion to technofunctional changes within the powder. The aim of this paper is to present in a non exhaustive manner the relationship between glass transition characteristics and applications in food technology (caking, alterations, etc.). [less ▲]

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See detailGlauben, wissen, feuern. Wirtschaftsjournalistische Kollokationen rund ums Management
Hümmer, Christiane; Münzberg, Franziska ULg

in Große, Sybille (Ed.) Angewandte Linguistik. Zwischen Theorien, Konzepten und der Beschreibung sprachlicher Äußerungen. (FS für Gerda Haßler) (2013)

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See detailGlaucome ou cataracte ? Sur l’emploi des dérivés de glaukos en ophtalmologie antique
Marganne, Marie-Hélène ULg

in History & Philosophy of the Life Sciences (1979), 1(2), 199-214

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See detailGlial but not neuronal development in the cochleo-vestibular ganglion requires Sox10.
Breuskin, Ingrid ULg; Bodson, Morgan ULg; Thelen, Nicolas ULg et al

in Journal of Neurochemistry (2010), 114(6), 1827-39

The cochleo-vestibular ganglion contains neural crest-derived glial cells and sensory neurons that are derived from the neurogenic otic placode. Little is known about the molecular mechanisms that ... [more ▼]

The cochleo-vestibular ganglion contains neural crest-derived glial cells and sensory neurons that are derived from the neurogenic otic placode. Little is known about the molecular mechanisms that regulate the tightly orchestrated development of this structure. Here, we report that Sox10, a high-mobility group DNA-binding domain transcription factor that is required for the proper development of neural crest cell derivatives, is specifically expressed in post-migratory neural crest cells in the cochleo-vestibular ganglion. Using Sox10-deficient mice, we demonstrate that this transcription factor is essential for the survival, but not the generation, of the post-migratory neural crest cells within the inner ear. In the absence of these neural crest-derived cells, we have investigated the survival of the otocyst-derived auditory neurons. Surprisingly, auditory neuron differentiation, sensory target innervation and survival are conserved despite the absence of glial cells. Moreover, brain-derived neurotrophic factor expression is increased in the hair cells of Sox10-deficient mice, a compensatory mechanism that may prevent spiral ganglion neuronal cell death. Taken together, these data suggest that in the absence of neural crest-derived glial cells, an increase trophic support from hair cells promotes the survival of spiral ganglion neurons in Sox10 mutant mice. [less ▲]

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See detailGlial control of neuronal excitability in mammals: I. Electrophysiological and isotopic evidence in culture.
Moonen, Gustave ULg; FRANCK, G.; SCHOFFENIELS, E.

in Neurochemistry International (1980), 2c

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See detailGlial organization in the developing reeler neocortex
Gadisseux, J.-F.; Evrard, Ph; Misson, Jean-Paul ULg et al

in Neuroscience (1988)

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See detailGlial process elongation and branching in the developing murine neocortex: A qualitative and quantitative immunohistochemical analysis
Takahashi, Takao; Misson, Jean-Paul ULg; Caviness, Verne S

in Journal of Comparative Neurology (The) (1990), 302

Detailed reference viewed: 20 (1 ULg)
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See detailLa gliceraldehido-3-fosfato deshidrogenasa plastidial es esencial para el desarrollo de polen maduro en Arabidopsis thaliana
Muñoz-Bertomeu, Jesús; Cascales - Miñana, Borja ULg; Flores-Tornero, Maria et al

Poster (2009, September)

Detailed reference viewed: 16 (0 ULg)