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See detailDiscrimination en prix
Aliaj, Arjeta ULiege

Master's dissertation (2010)

Detailed reference viewed: 44 (10 ULiège)
See detailDiscrimination et désaffiliation des jeunes issus de l’immigration
Perrin, Nathalie ULiege

Conference given outside the academic context (2014)

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See detailDiscrimination of animals treated with growth promoters
Scippo, Marie-Louise ULiege; Degand, Guy ULiege; Gaspar, Pol et al

in Meat Focus International (1993)

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See detailDiscrimination of deciduous tree species from time series of unmanned aerial system imagery
Lisein, Jonathan ULiege; Michez, Adrien ULiege; Claessens, Hugues ULiege et al

in PLoS ONE (2015), 10(11),

Technology advances can revolutionize Precision Forestry by providing accurate and fine forest information at tree level. This paper addresses the question of how and particularly when Unmanned Aerial ... [more ▼]

Technology advances can revolutionize Precision Forestry by providing accurate and fine forest information at tree level. This paper addresses the question of how and particularly when Unmanned Aerial System (UAS) should be used in order to efficiently discriminate deciduous tree species. A time series of high resolution UAS imagery was collected to cover the growing season from leaf flush to leaf fall. Full benefit was taken of the temporal resolution of UAS acquisition, one of the most promising features of small drones. The disparity in forest tree phenology is at the maximum during early spring and late autumn. But the phenology state that optimized the classification result is the one that minimizes the spectral variation within tree species groups and, at the same time, maximizes the phenologic differences between species. Sunlit tree crowns (5 deciduous species groups) were classified using a Random Forest approach for monotemporal, two-date and three-date combinations. The end of leaf flushing was the most efficient single-date time window. Multitemporal datasets definitely improve the overall classification accuracy. But single-date high resolution orthophotomosaics, acquired on optimal time-windows, result in a very good classification accuracy (overall out of bag error of 16%). [less ▲]

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See detailDiscrimination of epidemic and sporadic isolates of Serratia marcescens by three typing methods
Chetoui, Hafid; Delhalle, Edmond; Rousseaux, Danièle et al

Poster (1995, September)

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See detailDiscrimination of grassland species and their classification in botanical families by laboratory scale NIR hyperspectral imaging: preliminary results
Dale, Laura ULiege; Thewis, André ULiege; Boudry, Christelle ULiege et al

in Talanta (2013), 116

The objective of this study was to discriminate by a NIR line scan hyperspectral imaging, taxonomic plant families comprised of different grassland species. Plants were collected from semi-natural meadows ... [more ▼]

The objective of this study was to discriminate by a NIR line scan hyperspectral imaging, taxonomic plant families comprised of different grassland species. Plants were collected from semi-natural meadows of the National Apuseni Park, Apuseni Mountains, Gârda area (Romania) according to botanical families. Chemometric tools such as PLS-DA were used to discriminate distinct grassland species, and assign the different species to botanical families. Species within the Poacea family and Other Botanical Families could be distinguished (R2=0.91 and 0.90, respectively) with greater accuracy than those species in the Fabacea family (R2=0.60). A correct classification rate of 99% was obtained in the assignment of the various species to the proper family. Moreover a complete study based on wavelength selection has been performed in order to identify the chemical compound related to each botanical family and therefore to the possible toxicity of the plant. This work could be considered as a first step for the development of a complete procedure for the detection and quantification of possible toxic species in semi-natural meadows used by grazing animals. [less ▲]

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See detailDiscrimination of Isobaric Leu/Ile Residues by MALDI In-source Decay Mass Spectrometry
Asakawa, Daiki; Smargiasso, Nicolas ULiege; De Pauw, Edwin ULiege

in Journal of the American Society for Mass Spectrometry (2013), 24(2), 297-300

MALDI in-source decay (ISD) has been used for the top-down sequencing of proteins. The use of 1,5-diaminonapthalene (1,5-DAN) gave strong intensity of w ions, which are informative fragments and can be ... [more ▼]

MALDI in-source decay (ISD) has been used for the top-down sequencing of proteins. The use of 1,5-diaminonapthalene (1,5-DAN) gave strong intensity of w ions, which are informative fragments and can be helpful for the distinction of the isobaric amino acids, Leu and Ile. Our data suggests that the w fragments are formed from z* radical fragment by unimolecular dissociation and high abundance of w ions in MALDI-ISD with 1,5-DAN can be understood as resulting from the low collision rate in the MALDI plume. The MALDI-ISD with 1,5-DAN could be a useful method for the top-down sequencing of proteins including discrimination of Leu and Ile near the C-terminal end. [less ▲]

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See detailDiscrimination of mercury contamination sources and pathways using Hg stable isotopes in the European seabass, Dicentrarchus labrax
Cransveld, Alice ULiege

Doctoral thesis (2017)

Mercury (Hg) is a persistent toxic compound whose amount in the global biosphere has at least tripled since industrialization. The biogeochemical cycle of mercury is particularly complex because elemental ... [more ▼]

Mercury (Hg) is a persistent toxic compound whose amount in the global biosphere has at least tripled since industrialization. The biogeochemical cycle of mercury is particularly complex because elemental mercury is very volatile, has a long residence time in the atmosphere and thus can potentially reach locations that are very distant from the initial emission source. Since the 70’s, many international organisations (OECD, EU, UNEP) have implemented different policies to reduce Hg pollution. However, for these policies to be efficient, the polluters/Hg sources have to be fully assessed and identified. So, there is a crucial need to trace Hg sources and to assess the quantitative impact of local versus global Hg sources on ecosystems. Recently, the study of the seven Hg stable isotopes has emerged as a new promising technique affording to explore the Hg cycle both in situ and in laboratory. Mercury stable isotopes display both mass dependent fractionation (MDF, reported as δ202Hg) and mass independent fractionation (MIF, reported as Δ199Hg and Δ201Hg). The combination of both values should allow to trace back sources and pathways of Hg and methylmercury (MeHg). But, so far, few studies have considered Hg isotopes in marine vertebrates. Thus, the general objective of this thesis was to study a marine predator, the European seabass, Dicentrarchus labrax, to explore the possibility of using mercury stable isotopes to investigate Hg sources and pathways in European coastal waters. Our specific objectives were to characterize the Hg profile (THg, MeHg and isotopy) of wild populations of seabass, to assess whether Hg isotopes differed between populations and could give indications on Hg sources, with special attention paid to differentiate local versus global Hg sources. We also wanted to explore internal variation of Hg profiles by comparing several tissues. And, we wanted to validate our interpretations of in situ results by experimentally evaluating the potential fractionation between muscle and liver tissues of D. labrax, and between the diet and fish tissues. To fulfill our objectives, we split the thesis in 3 axes. First, juvenile seabass were collected in seven geographically distinct locations: the Agiasma lagoon in the northern Aegean Sea (AeS), the North Sea (NS) along Belgian and English coasts, the Seine estuary (SE), the Turkish coast of the Black Sea (BS), the Marano and Grado lagoons in the northern Adriatic Sea (NAS), the Portuguese lagoon, Ria de Aveiro, at two distinct sites: a very contaminated one (RAC) and a least contaminated one (RAR). v Our results showed seabass displayed extremely variable THg (Total mercury) concentrations amongst locations. Environmental contamination of the fish habitats seemed to be the main driving factor of THg concentrations in their tissues. Then, we showed that the populations also had distinct Hg isotopic niches (using SIBER on Hg stable isotopes, a premiere!), and that Hg isotopes (Δ199Hg and δ202Hg) could be used as a discriminating tool. We showed that Hg isotopes also told more about the origin of THg contaminating juvenile seabass: Δ199Hg values indicated a rather coastal MeHg source while δ202Hg could be linked with the global versus local Hg origin. Some populations like AeS were thought to be affected mainly by background, global Hg source, while other sites such as RAC (and SE and NAS) that were more heavily contaminated, would undergo a strong influence of local contamination. The previous observations were made in muscle tissue. Since different tissues often have distinct turnover times and different affinity for pollutants, the second axis of this thesis aimed at comparing liver and muscle results. So, we investigated the liver tissue of the very same individuals than in axis 1. The THg RATIO (THgliver/THgmuscle) was very variable amongst populations. We found that Hg organotropism (affinity for different organs) was influenced by the overall contamination level and maybe also by the food regime (via the %MeHg in diet). The Hg isotope composition also differed between muscle and liver of wild seabass. Hg speciation was most probably not the only cause of such a difference, and there was certainly an internal fractionating process (MDF). We even found serious indication of mercury demethylation happening in seabass, although demethylation in fish had yet to be proven. This is what our 3rd axis addressed. We exposed captive juvenile seabass to environmentally relevant THg concentrations through the diet. Observations confirmed in situ results: Hg organotropism depends on the %MeHg in diet, and THg RATIOs < 1 are to be related to the extremely small proportion of inorganic Hg in the seabass diet. Most of all, we found strong and concordant indications of demethylation process occurring in seabass that would be responsible for the systematically distinct δ202Hg values observed between muscle and liver. In conclusion, our findings constitute the first large scale Hg stable isotope study, on a single fish species, from European coastal waters. They demonstrate the interest and relevance of using Hg stable isotopes to investigate the Hg cycle and sources on both small and large scales and show the possibility to differentiate between global and local Hg sources. This takes a crucial sense in the current context where tracing Hg contamination sources is necessary to implement efficient environmental policies. [less ▲]

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See detailDiscrimination of parasitized aphids by a hoverfly predator: effects on larval performance, foraging, and oviposition behavior
Almohamad, Raki; Verheggen, François ULiege; Francis, Frédéric ULiege et al

in Entomologia Experimentalis et Applicata (2008), 128(1), 73-80

The choice of oviposition site by female aphidophagous predators is crucial for offspring performance, especially in hoverflies whose newly hatched larvae are unable to move over large distance. Predator ... [more ▼]

The choice of oviposition site by female aphidophagous predators is crucial for offspring performance, especially in hoverflies whose newly hatched larvae are unable to move over large distance. Predator and parasitoid interactions within the aphidophagous guild are likely to be very important in influencing the choices made by predatory hoverfly females. In the present study, the foraging and oviposition behavior of the aphidophagous hoverfly Episyrphus balteatus DeGeer (Diptera: Syrphidae) was investigated with respect to the parasitized state of its aphid prey, Acyrthosiphon pisum Harris (Homoptera: Aphididae), that were parasitized by Aphidius ervi Haliday (Hymenoptera: Aphidiidae). We also recorded the number of eggs laid by hoverfly females when subjected to parasitized aphids. Furthermore, we studied the influence of being fed with parasitized aphids on hoverfly larval performance. Hoverfly females did not exhibit any preference for plants infested with unparasitized or aphids parasitized for 7 days. On the other hand, plants infested with mummies or exuvia were less attractive for E. balteatus. These results were correlated with (i) the number of eggs laid by E. balteatus females and (ii) larval performance. Thus, our results demonstrate that E. balteatus behavior is affected by parasitoid presence through their exploitation of aphid colonies. Indeed, hoverfly predators select their prey according to the developmental state of the parasitoid larvae. [less ▲]

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See detailDiscrimination of pure grassland species using NIR Hyperspectral Imaging
Dale, Laura ULiege; Bogdan, Anca Dorina; Pacurar, Florin Simion et al

Poster (2012, June 03)

The objective of this study was to discriminate by hyperspectral imaging system, SWIR ImSpector N25E, different pure grassland species (Festuca rubra L., Trifolium repens L., Agrostis capillaris L ... [more ▼]

The objective of this study was to discriminate by hyperspectral imaging system, SWIR ImSpector N25E, different pure grassland species (Festuca rubra L., Trifolium repens L., Agrostis capillaris L., Hieracium aurantiacum L., Arnica montana L.) into grassland species mixtures. All the samples were collected from natural meadows of the National Apuseni Park, Apuseni Mountains, Gârda area (Romania). The samples were air-dried, then prepared using the protocol for NIRS analysis adapted on the scanning linear system. For images acquisition, the Hyper See program was used. Then a model build under MatLab (PLS–DA) was used to discriminate pure species from the mixtures of two or three species. This analysis was carried out in order to see, on images obtained previously from the floristic composition of experimental parcels, if the pure species are or are not recognized according to the spectral data base. More than 99% correct predictions for species discrimination were obtained. This study should guide us to verify if a toxic species is present or not in natural meadows used as food for animals. The floristic composition of a meadow can be determinate only if we have in the data base, spectra for each identified species, as being part of the mixture. [less ▲]

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See detailDiscrimination of shifts in a soil microbial community assosciated with TNT-contamination using a functional ANOVA of 16S rRNA hybridized to oligonucleotide microarrays
Eyers; Smoot, J. C.; Smoot, L. M. et al

in Environmental Science & Technology (2006), 40

A functional ANOVA analysis of the thermal dissociation of RNA hybridized to DNA microarrays was used to improve discrimination between two soil microbial communities. Following hybridization of in vitro ... [more ▼]

A functional ANOVA analysis of the thermal dissociation of RNA hybridized to DNA microarrays was used to improve discrimination between two soil microbial communities. Following hybridization of in vitro transcribed 16S rRNA derived from uncontaminated and 2,4,6- trinitrotoluene contaminated soils to an oligonucleotide microarray containing group- and species-specific perfect match (PM) probes and mismatch (MM) variants, thermal dissociation was used to analyze the nucleic acid bound to each PM-MM probe set. Functional ANOVA of the dissociation curves generally discriminated PM-MM probe sets when Td values (temperature at 50% probe-target dissociation) could not. Maximum discrimination for many PM and MM probes often occurred at temperatures greater than theTd. Comparison of signal intensities measured prior to dissociation analysis from hybridizations of the two soil samples revealed significant differences in domain-, group-, and species-specific probes. Functional ANOVA showed significantly different dissociation curves for 11 PM probes when hybridizations from the two soil samples were compared, even though initial signal intensities for 3 of the 11 did not vary. [less ▲]

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See detailDiscrimination of three genetically close Aspergillus species by using high resolution melting analysis applied to indoor air as case study.
Libert, Xavier; Packeu, Ann; Bureau, Fabrice ULiege et al

in BMC Microbiology (2017), 17(1), 84

BACKGROUND: Indoor air pollution caused by fungal contamination is suspected to have a public health impact. Monitoring of the composition of the indoor airborne fungal contaminants is therefore important ... [more ▼]

BACKGROUND: Indoor air pollution caused by fungal contamination is suspected to have a public health impact. Monitoring of the composition of the indoor airborne fungal contaminants is therefore important. To avoid problems linked to culture-dependent protocols, molecular methods are increasingly being proposed as an alternative. Among these molecular methods, the polymerase chain reaction (PCR) and the real-time PCR are the most frequently used tools for indoor fungal detection. However, even if these tools have demonstrated their appropriate performance, some of them are not able to discriminate between species which are genetically close. A solution to this could be the use of a post-qPCR high resolution melting (HRM) analysis, which would allow the discrimination of these species based on the highly accurate determination of the difference in melting temperature of the obtained amplicon. In this study, we provide a proof-of-concept for this approach, using a dye adapted version of our previously developed qPCR SYBR(R)Green method to detect Aspergillus versicolor in indoor air, an important airborne fungus in terms of occurrence and cause of health problems. Despite the good performance observed for that qPCR method, no discrimination could previously be made between A. versicolor, Aspergillus creber and Aspergillus sydowii. METHODS: In this study, we developed and evaluated an HRM assay for the discrimination between A. versicolor, Aspergillus creber and Aspergillus sydowii. RESULTS: Using HRM analysis, the discrimination of the 3 Aspergillus species could be made. No false positive, nor false negatives were observed during the performance assessment including 20 strains of Aspergillus. The limit of detection was determined for each species i.e., 0.5 pg of gDNA for A. creber and A. sydowii, and 0.1 pg of gDNA for A. versicolor. The HRM analysis was also successfully tested on environmental samples. CONCLUSION: We reported the development of HRM tools for the discrimination of A. versicolor, A. creber and A. sydowii. However, this study could be considered as a study case demonstrating that HRM based on existing qPCR assays, allows a more accurate identification of indoor air contaminants. This contributes to an improved insight in the diversity of indoor airborne fungi and hence, eventually in the causal link with health problems. [less ▲]

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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 ULiege; 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 ULiege

Report (2005)

Detailed reference viewed: 80 (8 ULiège)
See detailDiscrimination self/non-self
Heinen, Ernst ULiege

in Encyclopedia of Life Sciences (2005)

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

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

Detailed reference viewed: 37 (0 ULiège)
See detailDiscriminations "ethno-raciales": comprendre, pour agir dans la relation d'aide?
Collin, Jonathan ULiege

Scientific conference (2017)

Cette conférence a d'abord examiné l'évolution sémantique observée - du racisme aux discriminations - et la manière de concevoir l'adjectif "ethno-raciales" que j'y associe. Quelques données chiffrées ... [more ▼]

Cette conférence a d'abord examiné l'évolution sémantique observée - du racisme aux discriminations - et la manière de concevoir l'adjectif "ethno-raciales" que j'y associe. Quelques données chiffrées relatives aux discriminations en Belgique et en Europe furent ensuite présentées. Enfin, une analyse en termes de gestion publique du stigmate et des interactions - interethniques - en face à face (Erving Goffman notamment) fut proposée. [less ▲]

Detailed reference viewed: 34 (6 ULiège)