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See detailImpact of soil management on earthworm diversity according to differential plowing and plant residue incorporation
Lemtiri, Aboulkacem ULg; Alabi, Taofic; Zirbes, Lara ULg et al

Poster (2012, July 02)

Earthworms are largely distributed in terrestrial ecosystems and their abundance and diversity in soils are significantly affected by biotic (macro- and micro-organisms) and abiotic factors: soil ... [more ▼]

Earthworms are largely distributed in terrestrial ecosystems and their abundance and diversity in soils are significantly affected by biotic (macro- and micro-organisms) and abiotic factors: soil properties (pH, texture, structure…); agricultural management system and climate change. Here, tillage effect of earthworm population combined with crops residual management was investigated and correlated with soils properties. From wheat experimental field plots, the diversity of earthworm according to the field crop management was assessed. Application of particular crop production practices such as the integration of different levels of crop residues, diverse parts of wheat straws, at the field level regulate earthworm diversity and population abundance. Indeed, tillage reduced earthworm population with a 35% rate also corresponding to changes in soil properties. Agricultural practices had to be adapted to include consideration on macro-invertebrate abundance and diversity to maintain efficient soil fertility and allow sustainable crop production [less ▲]

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See detailThe impact of soil texture on the selection of nesting sites by the Malachite Kingfisher (Alcedinidae: Alcedo cristata Pallas 1764)
Kisasa Kafutshi, Robert ULg; Aloni Komanda, Jules

in Ostrich: Journal of African Ornithology (2011), 82(3), 243-246

The first granulometrical analysis of soil samples from nesting banks of the Malachite Kingfisher Alcedo cristata is reported. In total 56 samples from the Kinshasa area were analysed. Three standardised ... [more ▼]

The first granulometrical analysis of soil samples from nesting banks of the Malachite Kingfisher Alcedo cristata is reported. In total 56 samples from the Kinshasa area were analysed. Three standardised particle size fractions were determined in all groups of samples (percentage of sand, clay and silt). Mean particle percentage of soil samples from banks occupied by Malachite Kingfishers averaged 10.8 ± 6.1 of silt, 11.6 ± 6.5 of clay and 81.4 ± 11.4 of sand. A significant difference was found in the proportion of clay between banks with and without kingfisher nests. The results of the present study hence suggest that, as has been documented in other burrowing bird species, soil texture determines the selection of nesting sites in the Malachite Kingfisher. Our results indicate that even a slight difference in the proportion of clay can substantially affect the suitability of banks for the establishment of nests. In fact, burrowing birds must find suitable soils whose structure allows for a good compromise between stability and hardness to dig out, which poses an energy challenge just before the breeding season. [less ▲]

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See detailImpact of sowing density and nitrogen fertilization on Rumex obtusifolius L. development in organic winter cereal crops
Stilmant, Didier; Bodson, Bernard ULg; Losseau, Céline

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 237-343

The control of Rumex obtusifolius L. (broad-leafed dock) is very important in organic farming systems. Indeed, concerns about managing this weed without the use of herbicides is one of the major factors ... [more ▼]

The control of Rumex obtusifolius L. (broad-leafed dock) is very important in organic farming systems. Indeed, concerns about managing this weed without the use of herbicides is one of the major factors limiting the uptake of these systems by conventional farmers. Against this backround, we analyzed the impact of two management practices on the development of R. obtusifolius populations in two winter cereal trials: spelt (triticum spelta [L.] thell.) and triticale (xtriticosecale [A.Camus]Wittm.). The management factors were sowing density (SD) and nitrogen fertilization (NF) at the tillering stage. The results showed that and increase in SD and NF led to stronger crop growth and better soil coverage by the end of sping, demonstrated by a significant decrease in photosynthetic active radiation (PAR) at soil level. However, although there was an SD effect, it was too weak in April to restrict an increase in R. obtusifolius populations through the recruitment of new R. obtusifulius plants. An increase in R. obtusifolius population density was also linked to an increase in the NF level, illustrating the nitrophilic character of this weed. Although an increase in SD and NF at the tillering stage led to a higher canopy density, these two practices failed to reduce R. Obtusifolius density in the cereal crops. Nevertheless, cereal yields were shown to be maintained or improved. Our results indicate that, even when combining weed harrowing and some cultural weed control methods, this perennial weed is difficult to control. [less ▲]

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See detailImpact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990–2010, using the regional climate model MAR
Franco, Bruno ULg; Fettweis, Xavier ULg; Lang, Charlotte et al

in Cryosphere (The) (2012), 6

With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the ... [more ▼]

With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with diminishing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an intelligent interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model, needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries. [less ▲]

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See detailThe impact of sperm precedence in malathion resistance transmission in populations of the red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)
Haubruge, Eric ULg; Arnaud, Ludovic; Mignon, Jacques ULg

in Journal of Stored Products Research (1997), 33(2), 143-146

Malathion resistance in the red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is actually a worldwide problem, and studies on resistance transmission are needed to improve ... [more ▼]

Malathion resistance in the red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is actually a worldwide problem, and studies on resistance transmission are needed to improve insecticide resistance management. Females of Tribolium castaneum commonly mate with several males, and the last batch of male sperm preferentially fertilizes subsequent eggs. This phenomenon, a particular form of sexual selection, helps to increase resistance transmission in populations of stored product insects. We confirmed the last male sperm precedence and, in the absence of further matings, examined the evolution of mixed susceptible and malathion-resistant progeny during a 3-month period. The proportion of resistant phenotypes in female progeny was 99.6 and 3%, respectively, after the first mating with a resistant male and the second mating with a susceptible one. When females thus mated twice were isolated from males, the proportion of the resistant phenotype increased to 34.1% after 30 days. From 72 days onwards, this proportion ranged from 14.2 to 29.7%. (C) 1997, Published by Elsevier Science Ltd. [less ▲]

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See detailImpact of steam explosion treatment on chemical configuration of Tall Fescue lignin : structural elucidation using NMR spectroscopy
Maniet, Guillaume ULg; Jacquet, Nicolas ULg; Gillet, Sébastien ULg et al

Poster (2014, November 24)

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass ... [more ▼]

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass could be used to produce high value products. To achieve this objective, pretreatment processes are required to allow the breakdown of lignocellulosic structure and increase accessibility of the material. In this way, steam explosion is a thermo-mechano-chemical pretreatment which allows the opening of lignocellulosic material structural components and includes modifications of the physical properties of the material, hydrolysis of hemicellulosic components and modification of the chemical structure of lignin [1]. This study is focused on the impact of various steam explosion treatments on the chemical configuration of tall fescue lignin. NMR analyses perform on the Festuca L. pretreated samples show variations of links with treatment intensity. Observations show double phenomen :re-polymerization and depolymerization of the lignin structure during steam explosion process [2]. In parallel, HPSEC analyses show modifications in the molecular weight of the lignin obtained after the steam explosion treatment. [less ▲]

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See detailImpact of storage and handling on metabolites in a human plasma standard reference material
Eppe, Gauthier ULg; Dodder, Nathan; Lippa, Katrice et al

Conference (2010, June)

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See detailImpact of storage at 4°C on the study of sludge drying emissions
Fraikin, Laurent ULg; Herbreteau, Benjamin; Chaucherie, Xavier et al

Conference (2010, September)

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See detailImpact of storage duration on the emissions of ammonia and VOC during the convective drying of urban residual sludges
Fraikin, Laurent ULg; Herbreteau, Benjamin; Chaucherie, Xavier et al

in Tsotsas, E.; Metzger, T.; Peglow, M. (Eds.) Proceedings of IDS 2010 - Drying 2010 (2010, October)

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See detailImpact of Storage Duration on the Gaseous Emissions during Convective Drying of Urban Residual Sludges
Fraikin, Laurent ULg; Salmon, Thierry ULg; Herbreteau, B. et al

in Chemical Engineering and Technology (2011), 34(7), 1172--1176

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See detailImpact of strenous exercise on the release of cardiac biomarkers
LE GOFF, Caroline ULg; MELON, Pierre ULg; Kaux, Jean-François ULg et al

in Meeusen, R; Duchateau, J; Roelands, B (Eds.) et al Book of Abstracts of the 17th annual Congress of the ECSS (2012, July)

Background: Cardiac troponins (cTn) are considered as the best biomarkers for detection of myocardial cell injury and NT-proBNP as the best for the cardiac insufficiency. In this study, cTnT was measured ... [more ▼]

Background: Cardiac troponins (cTn) are considered as the best biomarkers for detection of myocardial cell injury and NT-proBNP as the best for the cardiac insufficiency. In this study, cTnT was measured by new commercially available high-sensitive methods in subjects undergoing the Maasmarathon. Our aim was to compare cTnT and NT-proBNP levels in sportive subjects before and after a strenuous exercise. Materials and Methods: Twenty eight subjects (26 ♂, 42.5±11yo) underwent a race of 42.195 kilometers between Visé (Belgium) and Maastricht (The Netherlands). We drowned blood samples before (T0), just after (T1) and three hours after the race (T3). For all patients, cTnT concentrations were measured by high sensitive methods (hsTnT, Roche Diagnostics) on heparin plasma. The NT-proBNP was also determined with the kit Roche on heparin plasma. The protocol was approved by the ethics committee of the University of Liège (Belgium). All subjects gave their informed consent. All statistical analyses were performed using Medcalc version 8.1 for Windows. p-value <0.01 was regarded as statistically significant. Results and discussion: A significant difference between hsTnT concentrations at T0 and T1 (p<0.0001) was measured as well as between T0 and T3 (p<0.001) for NT-proBNP, but not between T1 and T3. This observation appeared only after a strenuous exercise but today this type of exercise is not reproduce easier in a laboratory of sport. Moreover, at this moment, nobody knows if these observations would have cardiac consequences at long terms. Conclusions: Measurement of cardiac troponins by high sensitive methods allows detecting significant release of biomarkers from the heart during exercise. The levels of NT-proBNP were found significantly increased but in less extent than TnThs. We think that the TnThs could be an interesting marker in the future to help sport medicine to detect risk of developing a cardiac problem. [less ▲]

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See detailImpact of strenuous exercise on the release of cardiac biomarkers
LE GOFF, Caroline ULg; MELON, Pierre ULg; Kaux, Jean-François ULg et al

in Biochimica Clinica (2013, May), 37(SS), 545

Background: Cardiac troponins (cTn) are considered as the best biomarkers for detection of myocardial cell injury and NT-proBNP as the best for the cardiac insufficiency. In this study, cTnT was measured ... [more ▼]

Background: Cardiac troponins (cTn) are considered as the best biomarkers for detection of myocardial cell injury and NT-proBNP as the best for the cardiac insufficiency. In this study, cTnT was measured by new commercially available high-sensitive methods in subjects un-dergoing the Maasmarathon. Our aim was to compare cTnT and NT-proBNP levels before and after the stress tests, in sportive subjects. Methods: Twenty eight subjects (26 ♂, 42.5±11yo) underwent a race of 42.195 kilometers be-tween Visé (Belgium) and Maastricht (The Netherlands). We drowned blood sample before (T0), just after (T1) and three hours after the race (T3). In all patients, cTnT concentrations were measured by high sensitive methods (hsTnT, Roche Diagnostics) on heparin plasma. The NT-proBNP was also determined with the kit Roche on heparin plasma. The protocol was approved by the ethics committee of the University of Liège (Belgium). All subjects gave their informed consent. All statistical analyses were performed using Medcalc version 8.1 for Windows. p-value <0.01 was regarded as statistically significant. Results: There was a significant difference between hsTnT concentrations at T0 and T1 (p<0.0001), and between T0 and T3 (p<0.001) for NT-proBNP, but not between T1 and T3. This observation appeared only after a strenuous exercise but today this type of exercise is not reproduce easier in a laboratory of sport. Moreover, at this moment, nobody knows if these observations would have cardiac consequences at long terms. Conclusions: Measurement of cardiac troponins by high sensitive methods allows detecting significant release of biomarkers from the heart during exercise. The value of NT-proBNP are also significant but less than TnThs. We think that the TnThs could be an interesting tool in the future to help sport medicine to detect risk of developing a cardiac problem in the future or a sudden death. [less ▲]

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See detailImpact of successive freezing-thawing cycles on 3-T magnetic resonance images of the digits of isolated equine limbs
Bolen, Géraldine ULg; Haye, Dimitri; Dondelinger, Robert ULg et al

in American Journal of Veterinary Research (2011), 72(6), 780-790

The purpose of this study was to assess the impact of freezing and thawing on MR images of equine feet examined ex vivo. Nine equine cadaver digits were first imaged at room temperature (T0). Among the 9 ... [more ▼]

The purpose of this study was to assess the impact of freezing and thawing on MR images of equine feet examined ex vivo. Nine equine cadaver digits were first imaged at room temperature (T0). Among the 9 digits, 3 (group 1) were imaged in a 3 Tesla MR system after one and after 2 freezing-thawing cycles. Digits of group 1 were thawed in a cold room at 4°C for 36h. Three other digits (group 2) were imaged after one freezing-thawing cycle. Digits of group 2 were thawed in a cold room at 4°C and then rescanned after 24h at room temperature. The last 3 digits (group 3) were scanned after one freezing-thawing cycle. Digits of group 3 were thawed at room temperature for 24h. Sequences used were Spin Echo (SE) T1, Turbo Spin Echo (TSE) T2 and proton density (PD), Short Tau Inversion Recovery (STIR), Double Echo Steady State (DESS), 3D Gradient Echo (GE) T1 and 2D GE T2*. Images obtained on the fresh limbs at room temperature were subjectively compared side by side to images obtained at the different freezing-thawing cycles. A quantitative analysis to assess signal change between examinations was realized by measuring signal to noise ratio (SNR). Visibility and margination of the anatomical structures of the foot and overall image quality were subjectively considered unchanged except for the hoof where the lamina was considered less visible distally after freezing and thawing in the GE T2* and in TSE T2 and PD sequences. Quantitative analysis demonstrated SNR changes in the bone marrow only in the distal phalanx in the SE T1 sequence when the feet were thawed at room temperature. When the feet were thawed in a cold room at 4°C, bone marrow SNR changes were present in the SE T1, GE T1 and TSE PD sequences. Signal changes were significant in the synovial recess when the thawing process was made at 4°C and not when the thawing process was at ambient temperature. The soft tissue structures and the hoof capsule showed significant changes with an increase of SNR, except in STIR, after freezing and thawing at 4°C and at room temperature. SNR changes in the soft tissues were mainly present in GE sequences. [less ▲]

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See detailThe Impact of Surface Higher Order Differentiability in Two-dimensional Contact Elements
Nguyen, Duc Tue ULg; RAUCHS, Gast; PONTHOT, Jean-Philippe

in Journal of Computational and Applied Mathematics (2013), 246C

The aim of this work is to propose new contact elements of higher order of differentiability for analysing two-dimensional frictionless contact problems. Several methods were proposed in the literature to ... [more ▼]

The aim of this work is to propose new contact elements of higher order of differentiability for analysing two-dimensional frictionless contact problems. Several methods were proposed in the literature to solve the problem caused by the lack of continuity resulting from the discretization. Among them are Bézier interpolation, Hermitian interpolation and splines. One of the difficulties in using Hermitian interpolation is to verify the partition of unity. Therefore, new elements that satisfy the C1 and C2 continuity at the interface are presented in this paper. These new contact elements are based on Hermitian polynomials for ensuring a higher order of continuity. The advantage is that this approach can be easily developed not only for linear elements but also for quadratic elements with higher order of differentiability. The performance of different surface representations is assessed through a comparison with a C0 surface discretization. Some numerical examples are used for assessing the accuracy and the convergence behaviour. [less ▲]

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See detailThe impact of surface higher order differentiability in two-dimensional contact elements
Nguyen, Duc-Tué; Rauchs, Gast; Ponthot, Jean-Philippe ULg

in Journal of Computational & Applied Mathematics (2013), 246

The aim of this work is to propose new contact elements of higher order of differentiability for analysing two-dimensional frictionless contact problems. Several methods were proposed in the literature to ... [more ▼]

The aim of this work is to propose new contact elements of higher order of differentiability for analysing two-dimensional frictionless contact problems. Several methods were proposed in the literature to solve the problem caused by the lack of continuity resulting from the discretization. Among them are Bézier interpolation, Hermitian interpolation and splines. One of the difficulties in using Hermitian interpolation is to verify the partition of unity. Therefore, new elements that satisfy the C1 and C2 continuity at the interface are presented in this paper. These new contact elements are based on Hermitian polynomials for ensuring a higher order of continuity. The advantage is that this approach can be easily developed not only for linear elements but also for quadratic elements with higher order of differentiability. The performance of different surface representations is assessed through a comparison with a C0 surface discretization. Some numerical examples are used for assessing the accuracy and the convergence behaviour [less ▲]

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See detailImpact of surface properties of lactic acid bacteria on the stability of emulsions
Ly, M. H.; Waché, Y.; Bouchez-Naïtali, M. et al

in Proceedings of the 2nd Mercosur Congress on Chemical Engineering – ENPROMER and 4th Mercosur Congress on Process Systems Engineering (2005, August)

Bacteria have physicochemical surface properties which depend on the chemical composition of the cell surface. These characters proceed from several type of physicochemical interactions and are involved ... [more ▼]

Bacteria have physicochemical surface properties which depend on the chemical composition of the cell surface. These characters proceed from several type of physicochemical interactions and are involved in attachment processes of microorganisms to surfaces. Thus they are of interest in several areas, as biomedicine, formation of biofilms and adhesion to apolar surfaces. Moreover, food matrix are complex heterogeneous media, which structure settles on interaction forces between molecules (van der Waals, electrostatic or structural forces…). When bacteria are present in a matrix, it is probable that their surface interacts with the other constituents. So far, few studies have mentioned this subject. In order to understand the involvement of cells surface properties in a food matrix, the effect of surface properties of lactic bacteria on the stability of model emulsions were studied. The results showed that the choice of a bacterium according to its surface properties may have a strong impact on the stability and on the behavior of an emulsion. [less ▲]

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See detailImpact of surfactants on the biotransformation of methyl ricinoleate into γ-decalactone by Yarrowia lipolytica
Aguedo, Mario ULg; Waché, Y.; Coste, F. et al

in Journal of Molecular Catalysis B : Enzymatic (2004), 29(1-6), 31-36

Surfactants play a key role in the biotechnological degradation of hydrophobic substrates, however this role is often misunderstood. During the biotransformation of methyl ricinoleate into the aroma ... [more ▼]

Surfactants play a key role in the biotechnological degradation of hydrophobic substrates, however this role is often misunderstood. During the biotransformation of methyl ricinoleate into the aroma compound γ-decalactone by the yeast Yarrowia lipolytica, a direct contact occurs between the surface of the cells and the small droplets of substrate. The impact of a series of surfactants on this process was investigated. Both ionic surfactants tested were toxic towards the yeast. This effect may be linked to a decrease in the cell membrane integrity. The interfacial area of the emulsion varied according to the non-ionic surfactant used, and this factor was correlated with the productivity of the biotransformation. By evaluating the effect of surfactants on the capacity of the cells to adhere to decane (MATH test), it was shown that the adhesion of methyl ricinoleate on yeast surface is not a rate-limiting point for the process. © 2004 Elsevier B.V. All rights reserved. [less ▲]

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