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See detailDiscrimination of two geographically distinct populations of sea bass Dicentrarchus labrax, using stable isotopic signatures of mercury (δ202Hg, Δ199Hg)
Cransveld, Alice ULg; Amouroux, David; Koutrakis, Emmanuil et al

Poster (2014, May 15)

Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on ... [more ▼]

Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on mercury's biogeochemical cycle at both local and global scale. In the present work, we investigate the possibility to use mercury isotopic signature in fish as a tool to discriminate different polluted areas and potential pollution sources. Indeed, Hg can exhibit both mass-dependent (MDF) and mass-independent fractionation (MIF). While MDF may occur during biological cycling inter alia and could be used to understand bioaccumulation processes, MIF provides a unique fingerprint of specific chemical pathways, such as photochemical transformations. In this context, information provided by Hg isotopes would help to improve environmental management strategies. A preliminary set of four and ten juvenile common sea bass, Dicentrarchus labrax were collected from the North Sea and the Aegean Sea respectively. T-Hg was analysed by direct mercury analyser (DMA), speciation by gas chromatography inductively coupled plasma mass spectrometer (GC-ICP-MS) and Hg isotope analysis were performed using cold vapour generation with multicollector ICP-MS. Total Hg concentrations in all tissues were higher in individuals from the North Sea ( Hgtot muscle=1,14 ± 0,48 mg.kg-1 dw) than from Greece (0,60 ± 0,06 mg.kg-1 dw). Speciation analysis shows that MeHg is the predominant form of Hg in muscle (89% MeHg on average) but not in liver (51% MeHg on average). Isotopic mass dependent values (δ202Hg) values were always higher in muscle than in liver and related to Hg species distribution. For mass independent isotopic signature, sea bass from the Aegean Sea had a systematically higher Δ199Hg value than individuals from the North sea (e.g.: 0,56 ± 0,05‰ and 0,32 ± 0,06‰ respectively in muscle). While mass dependent isotopic signature probably reflects some internal Hg metabolism, mass independent isotopic signature seems definitely site dependent. Such isotopic discrimination might be in agreement with difference in both mercury sources and cycling in the North and Aegean Seas. These preliminary results indicate that Hg isotopes may thus help to discriminate fish from different areas. This promising outcome must be further confirmed by extending the number of individuals and locations to be investigated. [less ▲]

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See detailDiscrimination positive et mobilité scolaire
Bouchat, Thérèse-Marie; Delvaux, Bernard; Hindryckx, Geneviève ULg

Report (2005)

Detailed reference viewed: 48 (8 ULg)
See detailDiscrimination self/non-self
Heinen, Ernst ULg

in Encyclopedia of Life Sciences (2005)

Detailed reference viewed: 18 (4 ULg)
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See detailDiscrimination thresholds of the reverberation in large volumes by naïve listeners
Billon, Alexis ULg; Embrechts, Jean-Jacques ULg

in Proceedings of the Acoustics 2012 Nantes conference (2012, April)

Detailed reference viewed: 26 (0 ULg)
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See detailLes discriminations à l'école
Italiano, Patrick ULg; Jacquemain, Marc ULg

Report (2014)

Le document fait la synthèse d'une enquête réalisée par le CLEO pour le Centre pour l'Egalité des chances entre 2010 et 2012. Il analyse la perception des discrimination par les enseignants, leur gravité ... [more ▼]

Le document fait la synthèse d'une enquête réalisée par le CLEO pour le Centre pour l'Egalité des chances entre 2010 et 2012. Il analyse la perception des discrimination par les enseignants, leur gravité, leurs évolutions. La synthèse montre que la discrimination liée au fonctionnement même du système scolaire sert de "toile de fond" à toutes les autres [less ▲]

Detailed reference viewed: 91 (9 ULg)
See detailLes discriminations et la désaffiliation des jeunes issus de l’immigration
Perrin, Nathalie ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 7 (0 ULg)
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See detailDiscriminative stimulus effects of ethanol with a conditioned taste aversion procedure: lack of acetaldehyde substitution
Quertemont, Etienne ULg

in Behavioural Pharmacology (2003), 14(4), 343-350

Acetaldehyde has been suggested to mediate a number of the pharmacological and behavioural effects of ethanol. Recently, several studies investigated the role of acetaldehyde in the subjective effects of ... [more ▼]

Acetaldehyde has been suggested to mediate a number of the pharmacological and behavioural effects of ethanol. Recently, several studies investigated the role of acetaldehyde in the subjective effects of ethanol, but obtained conflicting results. With the discriminative taste aversion (DTA) procedure, high acetaldehyde doses were shown to substitute for the discriminative stimulus effects of ethanol. In contrast, the operant drug discrimination protocol failed to show any substitution effect of acetaldehyde. Several methodological differences between the two procedures could explain these discrepancies, and particularly the absence of an individual discrimination criterion in the DTA procedure. In the present study, the DTA procedure was adapted to introduce such a criterion. In addition, the effects of acetaldehyde were compared with those of other drugs, for which the substitution effects for ethanol are well known. Rats were trained to discriminate 1.0 g/kg ethanol from saline in a DTA protocol. When the rats met the criterion of ethanol discrimination, various doses of several drugs were tested for their ethanol stimulus substitution effects: ethanol, acetaldehyde, dizocilpine, diazepam and nicotine. The results showed a clear dose-dependent discrimination of ethanol stimulus effects. In addition, dizocilpine fully substituted for ethanol, while diazepam only partially substituted. In contrast, both acetaldehyde and nicotine failed to substitute for ethanol. These results show that acetaldehyde is not significantly involved in the subjective and discriminative stimulus effects of ethanol. Acetaldehyde up to toxic doses did not substitute for the ethanol discriminative stimulus in the DTA protocol, when non-specific effects were carefully controlled. [less ▲]

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See detailDiscriminative stimulus effects of ethanol: Lack of interaction with taurine
Quertemont, Etienne ULg; Grant, Kathleen A.

in Behavioural Pharmacology (2004), 15(7), 495-501

Recent microdialysis studies showed that ethanol administration increases the release of taurine in various rat brain regions, and it was suggested that this increase in extracellular concentrations of ... [more ▼]

Recent microdialysis studies showed that ethanol administration increases the release of taurine in various rat brain regions, and it was suggested that this increase in extracellular concentrations of taurine might mediate some of the neurochemical effects of ethanol. Previous drug discrimination studies showed that positive modulators of the GABA(A) receptor consistently substituted for ethanol discriminative stimulus effects. Since taurine is also believed to modulate GABA(A) receptor activity, this study addressed the hypothesis that taurine mediates the discriminative stimulus effects of ethanol due to GABA(A) activation. Male Long-Evans rats were trained to discriminate water from either 1 or 2 g/kg ethanol. In a first experiment, various taurine doses (0-500 mg/kg) were tested to investigate whether taurine substitutes for ethanol. In a second experiment, rats were pretreated with either 500 mg/kg taurine or an equivalent volume of saline before testing for ethanol discrimination with various ethanol doses (0-2.0 g/kg). The results showed that taurine does not substitute for ethanol at any tested doses. In addition, taurine pretreatments failed to modify the dose-response curve for ethanol discrimination. These results demonstrate that taurine is not directly involved in mediating the discriminative stimulus effects of ethanol. It is therefore very unlikely that the brain release of taurine observed after ethanol administration is implicated in the major pharmacological effects of ethanol, i.e. positive modulation of GABA(A) receptor, that mediate its discriminative stimulus effects. [less ▲]

Detailed reference viewed: 16 (0 ULg)
See detailDiscussant
Martiniello, Marco ULg

Scientific conference (2015)

Detailed reference viewed: 13 (0 ULg)
See detailDiscussant
Martiniello, Marco ULg

Scientific conference (2009, January 28)

Detailed reference viewed: 3 (0 ULg)
See detailDiscussant and Reporter at the Colloquium: “Multiculturalism, Minorities and Citizenship”
Martiniello, Marco ULg

Scientific conference (1997, April 18)

Detailed reference viewed: 4 (0 ULg)
See detailDiscussant in the Colloquium: “Rethinking Ethnic and Racial Studies”
Martiniello, Marco ULg

Scientific conference (1997, May 16)

Detailed reference viewed: 2 (0 ULg)
Peer Reviewed
See detailDiscussant Panel on "Public-Private Partnerships: New Governance Arrangements"
Remy, Céline ULg

Conference (2014, November 27)

Detailed reference viewed: 17 (2 ULg)