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See detailBack to America: tracking the origin of European introduced populations of Quercus rubra L.
Merceron, Nastasia; Leroy, Thibault; Chancerel, Emilie et al

in Genome = Génome (2017), 60

Abstract: Quercus rubra has been introduced in Europe since the end of the 17th century. It is widely distributed today across this continent and considered invasive in some countries. Here, we ... [more ▼]

Abstract: Quercus rubra has been introduced in Europe since the end of the 17th century. It is widely distributed today across this continent and considered invasive in some countries. Here, we investigated the distribution of genetic diversity of both native and introduced populations with the aim of tracing the origin of introduced populations. A large sampling of 883 individuals from 73 native and 38 European locations were genotyped at 69 SNPs. In the natural range, we found a continuous geographic gradient of variation with a predominant latitudinal component. We explored the existence of ancestral populations by performing Bayesian clustering analysis and found support for two or three ancestral genetic clusters. Approximate Bayesian Computations analyses based on these two or three clusters support recent extensive secondary contacts between them, suggesting that present-day continuous genetic variation resulted from recent admixture. In the introduced range, one main genetic cluster was not recovered in Europe, suggesting that source populations were preferentially located in the northern part of the natural distribution. However, our results cannot refute the introduction of populations from the southern states that did not survive in Europe. [less ▲]

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See detailCompte-rendu de Rebeca Martín / Joaquim Parellada (eds.): Una horma para el cuento
Ceballos Viro, Alvaro ULiege

in Iberoamericana (2017), 65

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See detailCan we use semiochemicals to control Aphis craccivoraKoch?
Bayendi-Loudit, Sandrine ULiege; Yarou, Boni Barthélémy ULiege; Boullis, Antoine ULiege et al

Poster (2017, July)

Amaranthus hybridus L. (Amaranthaceae) is among the most important vegetable crop in several sub-Saharan countries. Aphis craccivora Koch (Homoptera: Aphididae) is an aphid species that cause significant ... [more ▼]

Amaranthus hybridus L. (Amaranthaceae) is among the most important vegetable crop in several sub-Saharan countries. Aphis craccivora Koch (Homoptera: Aphididae) is an aphid species that cause significant losses in absence of chemical control. In this laboratory research, we evaluate the efficiency of informative substances (E-b-farnesene, methyl salicylate, essential oil of Ocimum gratissimum L. and Ocimum basilicum L.) to repel aphids from their host plant. Our assays were carried out in plastic trays containing twenty-five amaranth plants. In each tray, twenty apterous A. craccivora adults were placed on the central plant (release plant) associated with a semiochemical releaser containing 100 µl of the substance to be tested diluted in paraffin oil. The number of aphids was then counted on each plant surrounding plants every three-days for twelve days. We observed a significant repulsive effect of O. gratissimum and O. basilicum essential oils, that considerably reduced the aphid population on the treated plant, compared to control. However, no repulsive effect of E-b-farnesene and methyl salicylate on aphids was observed. Bioactivities of these substances and their using as alternative aphicidal in integrated pest management are discussed [less ▲]

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See detailMigraine triggers and habituation of visual evoked potentials
Lisicki Martinez, Marco ULiege; Ruiz-Romagnoli, Emiliano; Piedrabuena, Raul et al

in Cephalalgia : An International Journal of Headache (2017)

Background: Identifying specific subsets of patients within the clinical spectrum of migraine could help in personalizing migraine treatment. Profiling patients by combining clinical characteristics and ... [more ▼]

Background: Identifying specific subsets of patients within the clinical spectrum of migraine could help in personalizing migraine treatment. Profiling patients by combining clinical characteristics and neurophysiological biomarkers is largely unexplored. We studied the association between migraine attack triggers and habituation of visual evoked potentials. Methods: We personally interviewed 25 patients about their migraine triggers following a structured list, and measured the N1-P1 habituation slope over six blocks of 100 averaged pattern-reversal VEP afterwards. Results: The mean number of triggers per patient was 4.52 1.42. Habituation slopes differed significantly between subjects who reported stress as a migraine trigger (deficient VEP habituation) and subjects who did not (preserved VEP habituation). For the remaining categories, the mean amplitude slope was always positive, indicating deficient habituation, and was not significantly different between subgroups. Conclusions: Migraine patients not reporting perceived stress as a trigger for their attacks might constitute a distinct clinic-physiological subset within the migraine spectrum. [less ▲]

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See detailPerformance of gridded and along-track altimetry products in eddy manifestation in the Western Mediterranean
Karimova, Svetlana ULiege

in Proc. IGARSS 2017 (2017, July)

In the present work, we assess the performance of different sea level anomaly (SLA) products in manifesting mesoscale eddies of the Western Mediterranean. As ‘ground truth’ in this study we use eddy ... [more ▼]

In the present work, we assess the performance of different sea level anomaly (SLA) products in manifesting mesoscale eddies of the Western Mediterranean. As ‘ground truth’ in this study we use eddy manifestations found in sea surface temperature (SST) fields of the region of interest. Co-location of eddies found in thermal imagery with closed contours of the fields of SLA showed that only anticyclonic eddies exceeding approx. 70 km in diameter can be more or less sustainably manifested in the fields of SLA and its derivatives. Detection of cyclonic eddies, presumably due to their small spatial and temporal scales and non-geostrophic nature, is problematic. A preliminary analysis of the along-track SLA data seemed to support the conclusions made for the gridded SLA products. Application of a vector geometry approach to eddy detection, in its turn, seems to lead to an excess of large cyclonic eddies and thus biasing resulting mesoscale eddy statistics. [less ▲]

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See detailAn approach to automated spiral eddy detection in SAR images
Karimova, Svetlana ULiege

in Proc. IGARSS 2017 (2017, July)

Satellite derived synthetic aperture radar (SAR) imagery frequently contains manifestations of coherent structures (eddies) of different spatial scale. However, due to strong dependence of SAR imaging on ... [more ▼]

Satellite derived synthetic aperture radar (SAR) imagery frequently contains manifestations of coherent structures (eddies) of different spatial scale. However, due to strong dependence of SAR imaging on the near-surface wind speed during the SAR acquisition, such eddy manifestations can be at great extent masked by the signatures of other, mostly atmospheric, phenomena. In the present paper, we propose a method for an automated detection of eddy manifestations visualized by surfactant films presenting on the water surface. The method proposed based on sequential application of image transformations aimed at masking atmospheric phenomena and highlighting the surfactant filaments manifesting eddies in SAR images. Thus extracted dark patches are being fitted by circles, and close co-location of several such circles would be considered an eddy manifestation. [less ▲]

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See detailConclusions des 53e Journées de Fanjeaux
George, Philippe ULiege

Conference given outside the academic context (2017)

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See detailMartre, muscardin, chat sylvestre et compagnie
Schockert, Vincianne ULiege; Libois, Roland ULiege; Lambinet, Clotilde ULiege

in Blerot, Philippe (Ed.) Le grand livre de la forêt (2017)

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See detailAntarctic sea ice trophic status
Van der Linden, Fanny ULiege; Moreau, Sébastien; Champenois, Willy ULiege et al

Poster (2017, July)

The sea ice ecosystem is characterized by steep gradients in temperature, salinity, light and nutrient availability. Despite these challenging environmental conditions, sea ice provides a dynamic habitat ... [more ▼]

The sea ice ecosystem is characterized by steep gradients in temperature, salinity, light and nutrient availability. Despite these challenging environmental conditions, sea ice provides a dynamic habitat for diverse communities of microorganisms. These communities include a wide variety of organisms from different taxonomic groups such as algae, bacteria, heterotrophic protists, fungi as well as viruses [Horner et al., 1992; Deming, 2010; Thomas and Dieckmann, 2010; Poulin et al., 2011]. In the frame of the YROSIAE project (Year-Round survey of Ocean-Sea-Ice-Atmosphere Exchanges), carried out at Cape Evans in McMurdo Sound (Antarctica) from Nov. 2011 to Dec. 2012, ice cores, seawater, and brine material were collected at regular time intervals. Physical properties (salinity, temperature, texture) and biogeochemical parameters (pCO2, dissolved inorganic carbon, total alkalinity, chlorophyll-a, macro-nutrients) were analysed. We will here particularly consider changes inused dissolved inorganic carbon (DIC) and chlorophyll-a (chl-a) , used as a proxiesy of net community production and autotrophic biomass, respectively. A high spatial and temporal variability in ice algal biomass and DIC evolution were observed. From spring, very high chl-a concentrations (>2400μg.L^(-1)) were observed at the bottom of the ice, a common feature of land fast ice in the McMurdo Sound. This suggests high primary production. However Strikingly, , at the same time, nutrients at the bottom of the ice increased significantly suggesting high heterotrophyremineralisation. In the middle of the ice column, evolution of DIC is was marked by a succession of autotrophic and heterotrophic phases. The overall increase of DIC suggests that the ice interior was rather heterotroph. Such sea ice system should expel CO2. Yet, strong under-saturation in CO2 and DIC depletion appeared at the ice surface, suggesting that sea ice was taking up CO2 from the atmosphere. On the whole, land fast sea ice in McMurdo Sound appears as a puzzling ecosystem. It is able to support elevated growth of autotrophic organisms at the bottom, but still appears to be heterotrophicin parallel to high remineralization, while the top of the ice appears to be rather heterotrophic but stilland able to pump CO2 from the atmosphere. [less ▲]

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See detailN2O production and cycling within Antarctic sea ice
Kotovitch, Marie ULiege; Tison, J.-L.; Fripiat, François ULiege et al

Poster (2017, July)

Nitrous oxide (N2O) is a potent greenhouse gas that has a lifetime of 114 years in the atmosphere and a global warming potential 300 time higher than that of CO2. However there are still large ... [more ▼]

Nitrous oxide (N2O) is a potent greenhouse gas that has a lifetime of 114 years in the atmosphere and a global warming potential 300 time higher than that of CO2. However there are still large uncertainties and gaps in the understanding of the N2O cycle in polar oceans and particularly associated to sea ice. Sources and sinks of N2O are therefore poorly quantified. To date, only one study by Randall et al. 2012 present N2O measurements in sea ice. They pointed out that sea ice formation and melt has the potential to generate sea-air or air-sea fluxes of N2O, respectively. The main processes (except the transport processes) involved in the N2O cycle within the aquatic environment are nitrification and denitrification. Recent observations of significant nitrification in Antarctic sea ice shed a new light on nitrogen cycle within sea ice. It has been suggested that nitrification supplies up to 70% of nitrate assimilated within Antarctic spring sea ice. Corollary, production of N2O, a by-product of nitrification, can potentially be significant. Our recent studies in Antarctic land fast ice in McMurdo Sound, confirmed this suggestion, where N2O release to the atmosphere was estimated to reach 4µmol.m-2.yr-1. But this assessment is probably an underestimation since it only accounts for dissolved N2O while a significant amount of N2O is likely to occur in the gaseous form like N2, O2 and Ar. We will then address the new tools to measure the bulk concentration of N2O (dissolved and gaseous) in sea ice, and the production of N2O by sympagic microorganisms - what process is dominant and how much N2O is produced - based on the first time series of N2O measurement in sea ice. The determination of the isotopic composition of N2O using cavity enhanced laser absorption spectroscopy technique (Off-axis ICOS) will allow us to determine the origin of these processes. [less ▲]

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See detailWhere does the methane entrapped in Antarctic sea ice come from?
Jacques, C.; Sapart, Célia Julia ULiege; Carnat, G. et al

Poster (2017, July)

Methane (CH4) atmospheric concentrations have increased by a factor of 2.5 since the beginning of the Industrial Era, mainly because of anthropogenic activities. However, between 1999 and 2006, CH4 growth ... [more ▼]

Methane (CH4) atmospheric concentrations have increased by a factor of 2.5 since the beginning of the Industrial Era, mainly because of anthropogenic activities. However, between 1999 and 2006, CH4 growth rate declined to a near-zero level, suggesting that an equilibrium had been reached. But, from 2007 on, atmospheric concentrations underwent a renewed growth, implying major ongoing changes in the CH4 global budget (Nisbet et al., 2016). These changes challenge our understanding on the contribution of existing sources, and in particular natural sources. Sea ice can strongly affect emissions of CH4 from the ocean, but the precise mechanisms are not well understood. Sea ice has long been considered as an inert and impermeable barrier, but recent studies have highlighted the existence of gas fluxes at the atmosphere-sea ice and sea ice-seawater interfaces (Kort et al., 2012; He et al., 2013; Zhou et al., 2014; Sapart et al., 2016). However, these fluxes are to date poorly understood and quantified. To improve future climate projections, we aim to investigate the control exerted by sea ice on the CH4 atmospheric budget. To unravel the impacts of the Antarctic sea ice physical environment on biogeochemical cycles, the AWECS (Antarctic Winter Ecosystem Climate Study) expedition was conducted between the 8th of June and the 12th of August 2013 in the Weddell Sea. Such an expedition provides a rare opportunity to obtain insights on the behaviour of sea ice during winter. Ice cores specifically dedicated to the investigation of gas dynamics were collected at ten different stations. In order to determine CH4 formation and removal pathways in sea ice, we used concentration and stable isotope analysis, which can help to distinguish different processes. Here, we present and discuss our first results of the isotopic composition of CH4 (δ13C and δ D) on sea ice cores from the Weddell Sea and the Ross Ice Shelf. This new dataset will help to determine the origin of the CH4 entrapped in Antarctic sea ice and its potential impact on the current and future atmospheric CH4 budget. [less ▲]

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See detailMultiple uprising invasions of Pelophylax water frogs, potentially inducing a new hybridogenetic complex
Dufresne, Christophe; Denoël, Mathieu ULiege; Di Santo, Lionel et al

in Scientific Reports (2017), 7

The genetic era has revolutionized our perception of biological invasions. Yet, it is usually too late to understand their genesis for efficient management. Here, we take the rare opportunity to ... [more ▼]

The genetic era has revolutionized our perception of biological invasions. Yet, it is usually too late to understand their genesis for efficient management. Here, we take the rare opportunity to reconstruct the scenario of an uprising invasion of the famous water frogs (Pelophylax) in southern France, through a fine-scale genetic survey. We identified three different taxa over less than 200 km2: the autochthonous P. perezi, along with the alien P. ridibundus and P. kurtmuelleri, which have suddenly become invasive. As a consequence, the latter hybridizes and may now form a novel hybridogenetic complex with P. perezi, which could actively promote its replacement. This exceptional situation makes a textbook application of genetics to early-detect, monitor and understand the onset of biological invasions before they pose a continental-wide threat. It further emphasizes the alarming rate of amphibian translocations, both at global and local scales, as well as the outstanding invasive potential of Pelophylax aliens. [less ▲]

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See detailNew models to predict microcarriers just-suspended state in bioreactors for stem cell culturel
Loubière, Céline; Olmos, Eric; Guedon, Emmanuel et al

Conference (2017, July)

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See detailWEATHERING ON THE DEVONIAN SLATES AND CHARACTERIZATION OF A BENTONITE LAYER IN THE WESTERWALD (GERMANY)
Fontaine, François ULiege; Hamaekers, Helen; Hoffmann, Andreas et al

Conference (2017, July)

The Westerwald region is one of the largest and oldest clay mining areas of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of ... [more ▼]

The Westerwald region is one of the largest and oldest clay mining areas of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The two main goals of this study are first to improve the knowledge on the weathering processes of the Devonian slates that led to the current setting of those clay deposits by studying the mineralogical and chemical composition of the clays with depth. The second goal is to characterize a bentonite layer underneath the Miocene basalt cover using quantitative X-ray diffraction, chemical analysis, BET, cation exchange capacity and scanning electron microscope. A 20 meter deep quarry mining the Devonian bedrock in southern Westerwald has been sampled on its entire depth. The XRD results show no significant variations of the mineralogy with depth, except for the phyllosilicates. The minerals of the < 2 μm fraction are illite, kaolinite, smectite and mixed-layers minerals (vermiculite-chlorite and illite-chlorite). The proportions of the minerals in the mixed-layers chlorite-vermiculite vary with depth. At the bottom of the quarry, the proportion of vermiculite is very low while in the top, the proportion of vermiculite is higher. This is explained by the degree of the weathering, logically more intense at the top of the quarry. Trace elements compositions are currently being investigated. A 3 meter thick greenish to brownish bentonite layer has been found in the eastern part of the Westerwald region. The XRD performed on different samples of this bentonite shows a relatively heterogeneous composition: montmorillonite (60-80%), kaolinite (5-12%), illite (0-7%), goethite (2-15%), talc (0-10%), K-feldspars (0-7%), plagioclase (0-4%) and traces of amphibole and pyroxene. This bentonite is probably the result of the weathering of volcanic ashes. Since there are not many outcrops of this bentonite layer, its spatial distribution is studied by drilling. [less ▲]

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See detailCognitive brain responses during circadian wake-promotion: evidence for sleep- pressure-dependent hypothalamic activations
Reichert, Carolin Franziska; Maire, Micheline; Gabel, Virginie et al

in Scientific Reports (2017), 7(1),

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See detailViolences conjugales : un dilemme pour la justice pénale ? Leçons d’une analyse des enregistrements statistiques effectués dans les parquets belges
Vanneste, Charlotte ULiege

in Champ pénal/Penal field (2017), XIV

Drawing on the analysis of statistics regarding Intimate Partner Violence collected on a large scale at the level of the Belgian prosecutors’ offices, the article reveals a wide gap between the zero ... [more ▼]

Drawing on the analysis of statistics regarding Intimate Partner Violence collected on a large scale at the level of the Belgian prosecutors’ offices, the article reveals a wide gap between the zero tolerance rhetoric conveyed in the normative discourse and actual implementation, which is generally weak and showing divergent judicial practices in the field. Faced with this dilemma, the highly contestable impact of the zero tolerance policy observed in preventing recidivism offers a substantial argument to revisit the role of the criminal justice system in this area. [less ▲]

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See detailViolences conjugales et justice pénale
Glowacz, Fabienne ULiege; Vanneste, Charlotte ULiege

Book published by CNRS Revue.Org (2017)

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