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See detailIsotopic abundance in the CN coma of comets: Ten years of measurements
Schulz, R.; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in Planetary and Space Science (2008), 56

Over the past 10 years the isotopic ratios of carbon ([SUP]12[/SUP]C/[SUP]13[/SUP]C) and nitrogen ([SUP]14[/SUP]N/[SUP]15[/SUP]N) have been determined for a dozen comets, bright enough to allow obtaining ... [more ▼]

Over the past 10 years the isotopic ratios of carbon ([SUP]12[/SUP]C/[SUP]13[/SUP]C) and nitrogen ([SUP]14[/SUP]N/[SUP]15[/SUP]N) have been determined for a dozen comets, bright enough to allow obtaining the required measurements from the ground. The ratios were derived from high-resolution spectra of the CN coma measured in the B[SUP]2[/SUP]â [SUP]+[/SUP]â X[SUP]2[/SUP]â [SUP]+[/SUP] (0, 0) emission band around 387 nm. The observed comets belong to different dynamical classes, including dynamically new as well as long- and short-period comets from the Halley- and Jupiter-family. In some cases the comets could be observed at various heliocentric distances. All values determined for the carbon and nitrogen isotopic ratios were consistent within the error margin irrespective of the type of comet or the heliocentric distance at which it was observed. Our investigations resulted in average ratios of [SUP]12[/SUP]C/[SUP]13[/SUP]C=91±21 and nitrogen [SUP]14[/SUP]N/[SUP]15[/SUP]N=141±29. Whilst the value for the carbon isotopic ratio is in good agreement with the solar and terrestrial value of 89, the nitrogen isotopic ratio is very different from the telluric value of 272. [less ▲]

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See detailIsotopic abundance of nitrogen and carbon in distant comets
Manfroid, Jean ULg; Jehin, Emmanuel ULg; Hutsemekers, Damien ULg et al

in Astronomy and Astrophysics (2005), 432(Letters), 5-8

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios have been determined in comets C/1995 O1 (Hale-Bopp), C/2001 Q4 ... [more ▼]

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios have been determined in comets C/1995 O1 (Hale-Bopp), C/2001 Q4 (NEAT) and C/2003 K4 (LINEAR) at heliocentric distances of, respectively, 2.7, 3.7 and 2.6 AU. These ratios have also been measured at rË 1 AU. No significant differences were found between all determinations, nor with the value obtained for other comets. If confirmed, the discrepancy between the nitrogen isotopic ratios from optical and millimeter measurements on CN and HCN would rule out HCN as a major parent of the cometary CN radicals. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programmes 270.C-5043, 073.C-0525 and 274.C-5015). [less ▲]

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See detailIsotopic abundances of carbon and nitrogen in Jupiter-family and Oort Cloud comets
Hutsemekers, Damien ULg; Manfroid, Jean ULg; Jehin, Emmanuel ULg et al

in Astronomy and Astrophysics (2005), 440(Letters), 21-24

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P ... [more ▼]

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P/1981 Q1 Howell, and in the chemically peculiar Oort Cloud comet C/1999 S4 (LINEAR). By comparing these measurements to previous ones derived for six other Oort Cloud comets (including one of Halley-type), we find that both the carbon and nitrogen isotopic ratios are constant within the uncertainties. The mean values are [SUP]12[/SUP]C/[SUP]13[/SUP]C ~= 90 and [SUP]14[/SUP]N/[SUP]15[/SUP]N ~=145 for the eight comets. These results strengthen the view that CN radicals originate from refractory organics formed in the protosolar molecular cloud and subsequently incorporated in comets. [less ▲]

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See detailIsotopic and geochemical constraints on the evolution of the Mazury granitoids (NE Poland)
Baginski, Boguslaw; Duchesne, Jean-Clair ULg; Martin, Hervé et al

in Koslowski, A.; Wiszniewska, Janina (Eds.) Granitoids in Poland (2007)

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See detailIsotopic Composition and sources of Organic Carbon Pools within the Tana River Basin, (Kenya)
Tamooh, F.; Van Den Meersche, K.; Borges, Alberto ULg et al

Poster (2011)

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See detailIsotopic constraints on the Cenozoic evolution of the carbon cycle
François, Louis ULg; Godderis, Y.

in Chemical Geology (1998), 145(3-4), 177-212

In the last few years, several models have been built to explore the Cenozoic evolution of the carbon and strontium cycles. Of particular interest is the study of the impact on the carbon cycle of major ... [more ▼]

In the last few years, several models have been built to explore the Cenozoic evolution of the carbon and strontium cycles. Of particular interest is the study of the impact on the carbon cycle of major mountain uplifts such as the Himalayan orogeny. To explain the Cenozoic increase in the measured seawater strontium isotopic ratio, it was recently proposed that the Himalyan uplift could be responsible for an enhanced consumption of atmospheric CO2 by continental silicate weathering. Here, a new model of the carbon cycle evolution over Cenozoic times is presented. It calculates the various fluxes involved in the organic and inorganic components of the carbon cycle from the seawater delta C-13, the biological isotopic fractionation in the ocean and the seafloor spreading rate. The model equilibrates the budgets of the carbon and alkalinity cycles on the million year timescale, assuming as many previous investigators that the system remains close to equilibrium. The validity of this equilibrium approximation is examined critically. Various sensitivity experiments are performed in order to test the impact of the model parameters on the results. The calculated history of the carbonate deposition rate is consistent with the available reconstruction. The continental silicate weathering rate calculated by the model appears to be widely insensitive to the model parameters, showing three distinct evolutions over the Cenozoic. The model indeed suggests a time of relative constancy of the silicate weathering flux before 40 Ma, followed by a period of slow decrease until 15 Ma and finally a marked increase up to the present. In a progressively cooler world, this evolution may be interpreted as a change from a 'chemically' controlled to a 'physically' controlled weathering regime. The evolution of continental silicate weathering thus partly appears decoupled from the increase in the observed seawater strontium isotopic ratio. For this reason, the evolution of the calculated riverine Sr-87/ Sr-86 ratio shows a strong increase over the Cenozoic, from about 0.710 to 0.712. However, this increase may largely be reduced by considering the recycling of a pelagic carbonate reservoir increasing over the Cenozoic or by assuming that seafloor basalt weathering is a CO2- or climate-dependent process. (C) 1998 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailIsotopic constraints on the genesis of the anorthosite suite of rocks
Demaiffe, Daniel; Weis, Dominique; Michot, Jean et al

in Chemical Geology (1986), 57

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See detailIsotopic ratios and elemental contents as indicators of seagrass C processing and sewage influence in a tropical macrotidal ecosystem (Madagascar, Mozambic channel)
Lepoint, Gilles ULg; Frederich, Bruno ULg; Gobert, Sylvie ULg et al

in Scientia Marina (2008), 72(1), 109-117

Isotopic ratios and elemental concentrations of carbon and nitrogen were measured in seven seagrass species colonising different tidal flats near Toliara (SW Madagascar) in order to determine the ... [more ▼]

Isotopic ratios and elemental concentrations of carbon and nitrogen were measured in seven seagrass species colonising different tidal flats near Toliara (SW Madagascar) in order to determine the potential use of these parameters for assessing C processing and sewage use by tropical seagrasses. Nitrogen concentrations measured in upper intertidal seagrasses near Toliara were almost twice those measured on the tidal flat near a healthy mangrove situated 20 km away from Toliara town. At Toliara Beach, δ15N values were correlated with the N concentrations of Halodule sp., one of the dominant species on the tidal flat. This correlation did not exist for Halophila ovalis, the other dominant species. An increase in N concentrations and δ15N values demonstrates the influence of sewage coming directly onto Toliara Beach on the N cycles of intertidal seagrasses. Nevertheless, this influence seems restricted to the upper littoral zone and was not the main cause of seagrass die-off. On the other hand, at the mangrove site, δ15N values were not correlated with the N concentrations of Halodule sp. or Thalassia hemprichii, showing that natural δ15N variability is driven by other factors than the δ15N of N sources. Moreover, inter-individual variability of δ15N values was greater than inter-specific or inter-site variability, making the δ15N difficult to interpret in the context of human-disturbance influence on the N cycle of tropical seagrasses. δ13C values were close to -9‰, indicating the use of HCO 3– as an inorganic carbon source by the seven investigated species. Contrary to our hypothesis, variation between sites and location on the tidal flat was limited, suggesting limited impact on δ13C values of sewage, emersion duration and mechanisms for HCO 3– incorporation. [less ▲]

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See detailIsotopic Ratios in Comets: Status and Perspectives
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Hutsemekers, Damien ULg et al

in Earth, Moon, and Planets (2009), 105

Isotopic abundance ratios are excellently suited to probe the origin of solar system matter. We review the recent measurements of the isotopic ratios of the light elements (D/H, [SUP]12[/SUP]C/[SUP]13 ... [more ▼]

Isotopic abundance ratios are excellently suited to probe the origin of solar system matter. We review the recent measurements of the isotopic ratios of the light elements (D/H, [SUP]12[/SUP]C/[SUP]13[/SUP]C, [SUP]16[/SUP]O/[SUP]18[/SUP]O, [SUP]14[/SUP]N/[SUP]15[/SUP]N, [SUP]32[/SUP]S/[SUP]34[/SUP]S) in cometary dust and gas and discuss briefly their implications. Special emphasis will be put on the determinations and progress performed in the field over the past years thanks to high resolution spectroscopy of cometary comae obtained with the ESO Very Large Telescope. Future perspectives from space missions and ground-based observations with new large and extremely large telescopes operating in the optical, infrared and submillimeter wavelengths will be presented. [less ▲]

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See detailIsotopic tracing of sediment components that are assimilated by epibiontic juveniles of Holothuria scabra (Holothuroidea)
Plotieau, Thomas; Lepoint, Gilles ULg; Lavitra, Thiery et al

in Journal of the Marine Biological Association of the United Kingdom (in press)

Despite H. scabra’s wide distribution and status as one of the best candidates for sustaining the development of tropical sea cucumber aquaculture, very few data are available regarding the organic ... [more ▼]

Despite H. scabra’s wide distribution and status as one of the best candidates for sustaining the development of tropical sea cucumber aquaculture, very few data are available regarding the organic fraction it assimilates in practice. In this study we report experimental results where H. scabra’s diet was supplemented with various 15N-labelled organic fractions of sediment. We used juveniles weighing between 38- 88 mg at the beginning of the experiment (ca. 2 cm long and 30 days old). Their growth was measured over a four week period and their 15N composition recorded. The results showed that H. scabra juveniles assimilated all added organic components from both dissolved and particulate fractions of the sediment. Bacteria seem to be an important food source for juveniles, even more so than microphytobenthos (diatoms). [less ▲]

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See detailIsotopically labeled proteome as an internal standard for multiple reaction monitoring-based biomarker quantification.
Turtoi, Andrei ULg; Castronovo, Vincenzo ULg

in Expert Review of Proteomics (2012), 9(3), 245-8

Multiple reaction monitoring is a mass spectrometry technology used to selectively identify and quantify a known molecule in a complex mixture. The technology has gained favor in proteomic applications ... [more ▼]

Multiple reaction monitoring is a mass spectrometry technology used to selectively identify and quantify a known molecule in a complex mixture. The technology has gained favor in proteomic applications, especially for biomarker quantification in human samples. For this purpose, employment of internal standard consisting of isotopically (heavy) labeled proteins is currently considered the best way of normalizing sample preparation and correcting for different ionization efficiencies. However, synthesis of heavy-labeled proteins is considered laborious and expensive. The work outlined here presents an efficient strategy of utilizing isotope-labeled amino acids in cell culture to produce heavy-labeled proteins. These are then spiked into serum and serve as internal standards to relatively quantify a large number of target proteins. The method has been applied to quantify 72 proteins in the sera of pancreatic cancer patients with remarkable efficiency and accuracy. [less ▲]

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See detailIsotropic continuum damage/repair model for alveolar bone remodelling
Mengoni, Marlène ULg; Ponthot, Jean-Philippe ULg

in Journal of Computational & Applied Mathematics (2010), 234

Several authors have proposed mechanical models to predict long term tooth movement, considering both the tooth and its surrounding bone tissue as isotropic linear elastic materials coupled to either an ... [more ▼]

Several authors have proposed mechanical models to predict long term tooth movement, considering both the tooth and its surrounding bone tissue as isotropic linear elastic materials coupled to either an adaptative elasticity behavior or an update of the elasticity constants with density evolution. However, tooth movements obtained through orthodontic appliances result from a complex biochemical process of bone structure and density adaptation to its mechanical environment, called bone remodeling. This process is far from linear reversible elasticity. It leads to permanent deformations due to biochemical actions. The proposed biomechanical constitutive law, inspired from Doblaré and García (2002) [30], is based on a elasto-viscoplastic material coupled with Continuum isotropic Damage Mechanics (Doblaré and García (2002) [30] considered only the case of a linear elastic material coupled with damage). The considered damage variable is not actual damage of the tissue but a measure of bone density. The damage evolution law therefore implies a density evolution. It is here formulated as to be used explicitly for alveolar bone, whose remodeling cells are considered to be triggered by the pressure state applied to the bone matrix. A 2D model of a tooth submitted to a tipping movement, is presented. Results show a reliable qualitative prediction of bone density variation around a tooth submitted to orthodontic forces. [less ▲]

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See detailAn isozyme study in Bilberry (Vaccinium myrtillus ) 2. Mating system and genetic structure
Jacquemart, Anne Laure; Mahy, Grégory ULg; Raspé, Olivier et al

in Belgian Journal of Botany (1994), 127

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See detailISSD : An Interactive Software for Structural Design
Latteur, Pierre ULg; Lejeune, Marc

(1998, February)

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See detailISSD : Interactive Software for Structural Design
Latteur, Pierre ULg; Houdart, Sebastien; Rebora

Software (2009)

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See detailIssledovanie stoyanki Kulbulak v 2009 g.
Derevianko, A.P.; Kolobova, K.A.; Flas, Damien ULg et al

in Problems of archaeology, ethnography and anthropology of Siberia and adjacent territories: material of the 17th annual session of the Institute of Archaeology and Ethnography, SBRAS (2009)

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See detailIssledovanie stoyanki Kulbulak v 2010 godou
Derrevianko, A.P.; Kolobova, K.A.; Pavlenok, K.K. et al

in Problems of archaeology, ethnography and anthropology of Siberia and adjacent territories: material of the 18th annual session of the Institute of Archaeology and Ethnography, SBRAS (2010)

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See detailThe issue of third in same-sex (lesbian) parenting
Naziri, Despina ULg

Conference (2013, June 24)

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