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See detailImpact of microbiological processes on the cycling of Fe in Antarctic sea-ice during Spring
Schoemann, Véronique; Lannuzel, Delphine; Becquevort, Sylvie et al

Poster (2006, February)

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See detailImpact of Missing Data on Phylogenies Inferred from Empirical Phylogenomic Data Sets
Roure, Béatrice; Baurain, Denis ULg; Philippe, Hervé

in Molecular Biology and Evolution (2013), 30(1), 197-214

Progress in sequencing technology allows researchers to assemble ever-larger supermatrices for phylogenomic inference. However, current phylogenomic studies often rest on patchy data sets, with some ... [more ▼]

Progress in sequencing technology allows researchers to assemble ever-larger supermatrices for phylogenomic inference. However, current phylogenomic studies often rest on patchy data sets, with some having 80% missing (or ambiguous) data or more. Though early simulations had suggested that missing data per se do not harm phylogenetic inference when using sufficiently large data sets, Lemmon et al. (Lemmon AR, Brown JM, Stanger-Hall K, Lemmon EM. 2009. The effect of ambiguous data on phylogenetic estimates obtained by maximum likelihood and Bayesian inference. Syst Biol. 58:130-145.) have recently cast doubt on this consensus in a study based on the introduction of parsimony-uninformative incomplete characters. In this work, we empirically reassess the issue of missing data in phylogenomics while exploring possible interactions with the model of sequence evolution. First, we note that parsimony-uninformative incomplete characters are actually informative in a probabilistic framework. A reanalysis of Lemmon's data set with this in mind gives a very different interpretation of their results and shows that some of their conclusions may be unfounded. Second, we investigate the effect of the progressive introduction of missing data in a complete supermatrix (126 genes × 39 species) capable of resolving animal relationships. These analyses demonstrate that missing data perturb phylogenetic inference slightly beyond the expected decrease in resolving power. In particular, they exacerbate systematic errors by reducing the number of species effectively available for the detection of multiple substitutions. Consequently, large sparse supermatrices are more sensitive to phylogenetic artifacts than smaller but less incomplete data sets, which argue for experimental designs aimed at collecting a modest number (∼50) of highly covered genes. Our results further confirm that including incomplete yet short-branch taxa (i.e., slowly evolving species or close outgroups) can help to eschew artifacts, as predicted by simulations. Finally, it appears that selecting an adequate model of sequence evolution (e.g., the site-heterogeneous CAT model instead of the site-homogeneous WAG model) is more beneficial to phylogenetic accuracy than reducing the level of missing data. [less ▲]

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See detailImpact of mitral regurgitation and myocardial viability on left ventricular reverse remodeling after cardiac resynchronization therapy in patients with ischemic cardiomyopathy.
Senechal, Mario; Lancellotti, Patrizio ULg; Magne, Julien ULg et al

in American Journal of Cardiology (2010), 106(1), 31-7

This study investigated the impact of ischemic mitral regurgitation (MR) severity and viability on left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT) in patients with ... [more ▼]

This study investigated the impact of ischemic mitral regurgitation (MR) severity and viability on left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT) in patients with ischemic cardiomyopathy. Severe MR and ischemic cardiomyopathy have been associated with lack of LV reverse remodeling after CRT. Fifty-seven consecutive patients with ischemic MR, LV ejection fraction < or =35%, QRS duration > or =120 ms, and intraventricular dyssynchrony > or =50 ms were prospectively included. Stress echocardiography was performed before CRT implantation. Viability in the region of the LV pacing lead was defined as the presence of viability in 2 contiguous segments. Response to CRT at 6 months was defined by evidence of > or =15% LV decrease in end-systolic volume. Severe MR was defined by an effective regurgitant orifice (ERO) area > or =20 mm(2). Thirty-three patients (58%) were responders at follow-up. Baseline ERO area and prevalence of severe MR were not different between responders and nonresponders (19 +/- 11 vs 21 +/- 13 mm(2), p = 0.67; 52% vs 53%, p = 0.84). In responders, MR was decreased by 58% (ERO 19 +/- 12 to 8 +/- 6 mm(2)). In the presence of viability in the region of the pacing lead, 74% (n = 29 patients) were responders (sensitivity 88%, specificity 58%); in the subgroup of patients with viability in the region of the pacing lead and severe MR, 83% (n = 17 patients) were responders. In conclusion, LV remodeling is frequent and ischemic MR decrease important in patients with viability in the region of the pacing lead without regard to MR severity. [less ▲]

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See detailImpact of mixing imperfections on yeast bioreactor performances: Scale-down reactor concept and related experimental tools
Delvigne, Frank ULg; Blaise, Yannick ULg; Destain, Jacqueline ULg et al

in Cerevisia and Biotechnology (2012), 37

A method combining environmental data extracted from the dissolved oxygen profile of a fed-batch bioreactor and a dynamic discrete Markov chain model has been presented in order to give more insight about ... [more ▼]

A method combining environmental data extracted from the dissolved oxygen profile of a fed-batch bioreactor and a dynamic discrete Markov chain model has been presented in order to give more insight about the glucose and dissolved oxygen fluctuations experienced by the microorganisms during cultivation in heterogeneous bioreactor. The fed-batch cultivation of Saccharomyces cerevisiae has been performed in a well-mixed and a partitioned scale-down reactor (SDR). The analysis of the environmental sequences has shown extended time lengths for the glucose availability and depletion sequences in the case of the SDR under a DO-controlled fed-batch culture. The Markov chain model developed in this work is able to capture the stochastic environmental events, i.e. in our case the environmental states experienced by the microorganisms crossing the tubular part of the SDR. The simulation results show clearly an extension of the starvation periods in the case of the culture performed in the SDR. The simulations have been performed at the single cells level allowing future improvements of our model and notably in the context of the population segregation phenomena occurring in fed-batch cultures. As a perspective, flow cytometry has been presented as a high-throughput analytical tool for the investigation of yeast physiology at the single cell level and in process-related conditions. [less ▲]

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See detailImpact of Mn oxides on Fe mobilization during podzolization
Cornelis, Jean-Thomas ULg; Titeux, Hugues; Caignet, Isabelle et al

Poster (2014)

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See detailImpact of model resolution on simulated wind, drifting snow and surface mass balance in Terre Adelie, East Antarctica
Lenaerts, J. T. M.; van den Broeke, Michiel R.; Scarchilli, Claudio et al

in Journal of Glaciology (2012), 58(211), 821

This paper presents the impact of model resolution on the simulated wind speed, drifting snow climate and surface mass balance (SMB) of Terre Ade ́lie and its surroundings, East Antarctica. We compare ... [more ▼]

This paper presents the impact of model resolution on the simulated wind speed, drifting snow climate and surface mass balance (SMB) of Terre Ade ́lie and its surroundings, East Antarctica. We compare regional climate model simulations at 27 and 5.5 km resolution for the year 2009. The wind speed maxima in Terre Ade ́lie and the narrow glacial valleys of Victoria Land are better represented at 5.5 km resolution, because the topography is better resolved. Drifting snow sublimation is >100 mm a−1 in regions with high wind speeds. Our results indicate a strong feedback between topography, wind gradients and drifting snow erosion. As a result, SMB shows much more local spatial variability at 5.5 km resolution that is controlled by drifting snow erosion, whereas the large-scale SMB gradient is largely determined by precipitation. Drifting snow processes lead to ablation in the narrow glacial valleys of Victoria Land. The integrated SMB equals 86 Gt. Although wind climate, drifting snow processes and SMB variability are better represented at 5.5 km, the area-integrated SMB is not significantly different between the simulations at 27 and 5.5 km. A horizontal resolution of 27 km is sufficient to realistically simulate ice-sheet wide SMB. [less ▲]

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See detailThe impact of model-based therapeutics on glucose control in an intensive care unit
Chase, JG; Hann, CE; Desaive, Thomas ULg et al

in Proceedings of the 4th European Congress for Medical and Biomedical Engineering (eMBEC 2008) (2008)

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See detailThe impact of model-based therapeutics on glucose control in an intensive care unit
Hann, C. E.; Chase, J. G.; Desaive, Thomas ULg et al

in IFMBE Proceedings (2008), 22

This paper investigates the impact of fast parameter identification methods, which do not require any forward simulations, on model-based glucose control, using retrospective data in the Christchurch ... [more ▼]

This paper investigates the impact of fast parameter identification methods, which do not require any forward simulations, on model-based glucose control, using retrospective data in the Christchurch Hospital Intensive Care Unit. The integral-based identification method has been previously clinically validated and extensively applied in a number of biomedical applications; and is a crucial element in the presented model-based therapeutics approach. Common non-linear regression and gradient descent approaches are too computationally intense and not suitable for the glucose control applications presented. The main focus in this paper is on better characterizing and understanding the importance of the integral in the formulation and the effect it has on model-based drug therapy control. As a comparison, a potentially more natural derivative formulation which has the same computation speed advantages is investigated, and is shown to go unstable with respect to modelling error which is always present clinically. The integral method remains robust. © 2009 Springer Berlin Heidelberg. [less ▲]

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See detailImpact of morphosyntactic complexity in sentence comprehension in children with SLI
Leclercq, Anne-Lise ULg; Majerus, Steve ULg; Jacob, Laura et al

Poster (2010, June)

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See detailThe impact of Motherhood on Women's Retirement Income : Six EU countries
Bould, Sally; Crespi, Isabella; Krekula, Clary et al

Conference (2014, July 17)

women have to face to a higher risk of widowhood but the incidence of divorce is also greater. Those life events have an impact on their economic security. Nevertheless, this impact is not the same in ... [more ▼]

women have to face to a higher risk of widowhood but the incidence of divorce is also greater. Those life events have an impact on their economic security. Nevertheless, this impact is not the same in each country.... [less ▲]

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See detailImpact of mutations affecting ND mitochondria-encoded Subunits on the activity and assembly of complex I in chlamydomonas. Implication for the structural organization of the enzyme
Cardol, Pierre ULg; Matagne, René-Fernand ULg; Remacle, Claire ULg

in Journal of Molecular Biology (2002), 319(5), 1211-1221

The mitochondrial rotenone-sensitive NADH:ubiquinone oxidoreductase (complex 1) comprises more than 35 subunits, the majority of which are encoded by the nucleus. In Chlamydomonas reinhardtii, only five ... [more ▼]

The mitochondrial rotenone-sensitive NADH:ubiquinone oxidoreductase (complex 1) comprises more than 35 subunits, the majority of which are encoded by the nucleus. In Chlamydomonas reinhardtii, only five components (ND1, ND2, ND4, ND5 and ND6) are coded for by the mitochondrial genome. Here, we characterize two mitochondrial mutants (dum5 and dum17) showing strong reduction or inactivation of complex I activity: dum5 is a IT deletion in the 3' UTR of nd5 whereas dum17 is a IT deletion in the coding sequence of nd6. The impact of these mutations and of mutations affecting nd1, nd4 and nd4/nd5 genes on the assembly of complex I is investigated. After separation of the respiratory complexes by blue native (BN)-PAGE or sucrose gradient centrifugation, we demonstrate that the absence of intact ND1 or ND6 subunit prevents the assembly of the 850 kDa whole complex, whereas the loss of ND4 or ND4/ND5 leads to the formation of a subcomplex of 650 kDa present in reduced amount. The implications of our findings for the possible role of these ND subunits on the activity of complex I and for the structural organization of the membrane arm of the enzyme are discussed. In mitochondria from all the strains analyzed, we moreover detected a 160210 kDa fragment comprising the hydrophilic 49 kDa and 76 kDa subunits of the complex I peripheral arm and showing NADH dehydrogenase activity. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailImpact of Mycosphaerella fijiensis toxins on banana antioxidant systems.
Busogoro, J. P.; Olivier, T.; Leiva, M. et al

Poster (2006)

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See detailImpact of Myzus persicae infestation on the volatile emission of Arabidopsis thaliana Col-0.
Hien, Truong Thi Dieu ULg; Delaplace, Pierre ULg; Francis, Frédéric ULg et al

Poster (2012, July 22)

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant ... [more ▼]

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant volatile emission, most of them either compare the influences of various herbivore species on one plant species or the impact of a given herbivore on several host plant species. Moreover, informations related to the influence of insect density as well as the infestation duration are still needed. Here, we showed that a sucking insect – Myzus persicae (green peach aphid) induced the volatile emission from Arabidopsis thaliana Columbia wild-type (A.thaliana Col-0) under laboratory conditions based on results obtained by solid-phase micro-extraction coupled with gas chromatography - mass spectrometry (SPME-GC/MS). The released volatile blend was discussed in relation to related biosynthesis pathways and functions. These included terpenoids, green leaf volatiles, alcohols and isothiocyanate. The qualitative and overall proportion of volatile components differed depended on the number and residence duration of aphids on leaves. By studying the effects of sucking insect stresses to plant, we not only aim to contribute to the fundamental understanding of the emission of volatile components in the interaction between plants and pests, but also to provide standardised and easy to use assays to assess A.thaliana volatile changes according to cross stresses, including both biotic and abiotic ones in ongoing experiments. [less ▲]

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See detailThe impact of naturally-occurring, trans-placental bluetongue virus serotype-8 infection on reproductive performance in sheep.
Saegerman, Claude ULg; Bolkaerts, Benoit; Baricalla, Christine et al

in Veterinary Journal (2011), 187(1), 72-80

Infection with bluetongue virus serotype (BTV)-8 occurred in ruminants in 2006 in Central-Western Europe. The trans-placental passage of this virus has been demonstrated in naturally- and experimentally ... [more ▼]

Infection with bluetongue virus serotype (BTV)-8 occurred in ruminants in 2006 in Central-Western Europe. The trans-placental passage of this virus has been demonstrated in naturally- and experimentally-infected cattle and in experimentally-infected sheep. Trans-placental transmission is potentially important in the 'over-wintering' of this virus and its subsequent impact on reproductive performance. This epidemiological study was carried out on a sheep flock in Belgium that had experienced a severe outbreak of BTV-8 infection, and where the seroprevalence had increased from 1.3% to 88% between January and November 2007. In total, 476 lambs and 26 aborted fetuses from 300 ewes, lambing at four distinct time periods, were investigated between November 2007 and May 2008. The following evidence suggested that BTV-8 infection occurred in utero: (1) positive PCR results from splenic tissue from aborted fetuses (n=4); (2) fetal malformations suggestive of BTV infection (n=10); (3) positive PCR results from red blood cells in-lambs (n=7), and (4) the presence of antibody at birth in viable lambs prior to the intake of colostrum (n=9). The evidence provided by this investigation strongly suggests that trans-placental BTV-8 infection occurs in naturally-infected sheep and the impact of infection on the reproductive performance of such a naive flock was considerable, with up to 25% of ewes aborting and with flock fertility reduced by 50%. The contribution of in utero-infected lambs to the over-wintering of BTV appears limited. [less ▲]

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See detailImpact of net metering programs on optimal load management in US residential housing – a case study
Georges, Emeline ULg; Braun, J. E.; Groll, E. et al

in Proceedings of 9th International Conference on System Simulation in Buildings (2014, December 11)

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See detailImpact of new technology on cognitive and organizational processes in surgery
Blavier, Adelaïde ULg

Scientific conference (2005, January 04)

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See detailImpact of noise correction on diffusion kurtosis estimation
André, Elodie ULg; Balteau, Evelyne ULg; Phillips, Christophe ULg et al

in Proceedings of the International Society for Magnetic Resonance in Medicine ... Scientific Meeting and Exhibition. International Society For Magnetic Resonance in Medicine. Scientific Meeting and Exhibition (2012), 20

Detailed reference viewed: 17 (7 ULg)