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See detailEffectiveness of temporary implants in teenage patients: a prospective clinical trial
LAMBERT, France ULg; BOTILDE, Gaëlle ULg; LECLOUX, Geoffrey ULg et al

in Clinical Oral Implants Research (2016)

Abstract Aims: The objective of this study was to assess prospectively the outcomes of extra-narrow diameter implants (XNDI) placed in teenage patients as a temporary restorative option. Material and ... [more ▼]

Abstract Aims: The objective of this study was to assess prospectively the outcomes of extra-narrow diameter implants (XNDI) placed in teenage patients as a temporary restorative option. Material and Methods: Twenty consecutive young patients presenting one or several missing teeth received XNDI that were immediately restored with composite, Polymethylmethacrylate (Acrylic) or ceramic crown. Clinical and radiographical outcomes were assessed for a minimum follow-up period of 1 year. Additionally, each patient completed retrospectively a satisfaction questionnaire using Visual Analog Scale (VAS). Results: A total of 30 implants were placed and followed for a period of 1–7.4 years (mean: 3.59 years). One implant failed after 3 weeks and was replaced successfully. No further biological complications occurred during the follow-up period, leading to an implant survival rate of 96.6%. The patient satisfaction evaluations displayed high levels of comfort and function. Conclusion: Immediately restored XNDI to replace missing teeth on teenager patients seems to be an effective temporary restorative option to replace missing teeth in young patients. Composite or ceramic crowns should be preferred. Clinical trials with long-term follow-ups and the assessment of passive egression are needed. [less ▲]

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See detailTen years of atmospheric methane from ground-based NDACC FTIR observations
Bader, Whitney ULg; Bovy, Benoît ULg; Conway, S. et al

in Atmospheric Chemistry & Physics Discussions (2016), 2016

Changes of atmospheric methane (CH4) since 2005 have been evaluated using Fourier Transform Infrared (FTIR) solar observations performed at ten ground-based sites, all members of the Network for Detection ... [more ▼]

Changes of atmospheric methane (CH4) since 2005 have been evaluated using Fourier Transform Infrared (FTIR) solar observations performed at ten ground-based sites, all members of the Network for Detection of Atmospheric Composition Change (NDACC). From this, we find an increase of atmospheric methane total columns that amounts to 0.31 ± 0.03 % year-1 (2-sigma level of uncertainty) for the 2005–2014 period. Comparisons with in situ methane measurements at both local and global scales show good agreement. We used the GEOS-Chem Chemical Transport Model tagged simulation that accounts for the contribution of each emission source and one sink in the total methane, simulated over the 2005–2012 time period and based on emissions inventories and transport. After regridding according to NDACC vertical layering using a conservative regridding scheme and smoothing by convolving with respective FTIR seasonal averaging kernels, the GEOS-Chem simulation shows an increase of atmospheric methane of 0.35 ± 0.03 % year-1 between 2005 and 2012, which is in agreement with NDACC measurements over the same time period (0.30 ± 0.04 % year-1, averaged over ten stations). Analysis of the GEOS-Chem tagged simulation allows us to quantify the contribution of each tracer to the global methane change since 2005. We find that natural sources such as wetlands and biomass burning contribute to the inter-annual variability of methane. However, anthropogenic emissions such as coal mining, and gas and oil transport and exploration, which are mainly emitted in the Northern Hemisphere and act as secondary contributors to the global budget of methane, have played a major role in the increase of atmospheric methane observed since 2005. Based on the GEOS-Chem tagged simulation, we discuss possible cause(s) for the increase of methane since 2005, which is still unexplained. [less ▲]

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See detailInvestigating the Effect of Plant Root Exudates and of Saponin on Polycyclic Aromatic Hydrocarbons Solubilization in Brownfield Contaminated Soils
Davin, Marie ULg; Fauconnier, Marie-Laure ULg; Colinet, Gilles ULg

Conference (2016, August 08)

In Wallonia, there are 6,000 estimated brownfields (rising to over 3.5 million in Europe) that require remediation. Polycyclic Aromatic Hydrocarbons (PAHs) are a class of recalcitrant carcinogenic ... [more ▼]

In Wallonia, there are 6,000 estimated brownfields (rising to over 3.5 million in Europe) that require remediation. Polycyclic Aromatic Hydrocarbons (PAHs) are a class of recalcitrant carcinogenic/mutagenic organic compounds of major concern as they accumulate in the environment and represent 17% of all encountered pollutants. As an alternative to environmentally aggressive, expensive and often disruptive soil remediation strategies, a lot of research has been directed to developing techniques targeting organic pollutants. The following experiment, based on the observation that PAHs soil content decreases in the presence of plants, aimed at improving our understanding of the underlying mechanisms involved in phytoremediation. It focusses on plant root exudates and whether they improve PAHs solubilization, which would make them more available for bioremediation by soil microorganisms. The effect of saponin, a natural surfactant found in some plant roots such as members of the Fabaceae family, on PAHs solubilization was also investigated as part of the implementation of the experimental protocol. The experiments were conducted on soil collected from a brownfield in Saint-Ghislain (Belgium) and presenting weathered PAHs contamination. Samples of soil were extracted with different solutions containing either plant root exudates or commercial saponin. Extracted PAHs were determined in the different aqueous solutions using High-Performance Liquid Chromatography and Fluorimetric Detection (HPLC-FLD). Both root exudates of alfalfa (Medicago sativa L.) or red clover (Trifoliumpratense L.) and commercial saponin were tested in different concentrations. Distilled water was used as a control. First of all, results show that PAHs are more extracted using saponin solutions than distilled water and that the amounts generally rise with the saponin concentration. However, the amount of each extracted compound diminishes as its molecular weight rises. Also, it appears that passed a certain surfactant concentration, PAHs are less extracted. This suggests that saponin might be investigated as a washing agent in polluted soil remediation techniques, either for ex situ or in situ treatments, as an alternative to synthetic surfactants. On the other hand, preliminary results on experiments using plant root exudates also show differences in PAHs solubilization compared to the control solution. Further results will allow discussion as to whether or not there are differences according to the exudates provenance and concentrations. [less ▲]

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See detailMEASUREMENT OF MOISTURE DIFFUSIVITY BY INVESTIGATION OF SORPTION ISOTHERM AND MODELING MOISTURE TRANSFER OF MORTAR SUBMITED TO CONVECTIVE DRYING
Kahlerras, Loubna ULg; BELHAMRI, Azeddine; Fraikin, Laurent ULg et al

in Proceedings of The 20th International Drying Symposium (IDS 2016) (2016, August 08)

This work reports the results of experimental study concerning convective drying of cement mortar and the influence of water-to cement ratios (W/C) used for the preparation of mortar, on moisture changes ... [more ▼]

This work reports the results of experimental study concerning convective drying of cement mortar and the influence of water-to cement ratios (W/C) used for the preparation of mortar, on moisture changes. The first experimental campaign was a convective dryer; in the purpose to obtain the drying curves of mortar and the influence of water to cement ratios (W/C) on drying kinetics. A second experimental campaign aims to characterize from textural and hydric point of view, the materials, by mean of DVS (dynamic vapor sorption) In order to obtain sorption cycles and identify the moisture diffusivity coefficient of mortar. The pore size distribution is obtained from sorption cycles and completed by MIP. The contribution of each components of the microstructure to the diffusion is studied. Finally X-ray microtomography is used to measuring the moisture content in the internal structure of mortars during drying. [less ▲]

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See detailMajor Changes in Growth Rate and Growth Variability of Beech (Fagus sylvatica L.) Related to Soil Alteration and Climate Change in Belgium
Latte, Nicolas ULg; Perin, Jérôme ULg; Kint, Vincent et al

in Forests (2016), 7(174),

Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth ... [more ▼]

Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L.) were investigated for the past 80 years in Belgium, using non-linear mixed effects models on ring-width chronologies of 149 mature and dominant beech trees (87–186 years old). The effects of the developmental stage (i.e., increasing tree size) were filtered out in order to focus on time-dependent growth changes. Beech radial growth was divided into a low-frequency signal (=growth rate), mainly influenced by forest management and atmospheric deposition, and into a high-frequency variability (≈mean sensitivity), mainly influenced by climate change. Between 1930 and 2008, major long-term and time-dependent changes were highlighted. The beech growth rate has decreased by about 38% since the 1950–1960s, and growth variability has increased by about 45% since the 1970–1980s. Our results indicate that (1) before the 1980s, beech growth rate was not predominantly impacted by climate change but rather by soil alteration (i.e., soil compaction and/or nitrogen deposition); and (2) since the 1980s, climate change induced more frequent and intense yearly growth reductions that amplified the growth rate decrease. The highlighted changes were similar in the two ecoregions of Belgium, although more pronounced in the lowlands than in the uplands. [less ▲]

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See detailGreenland Ice sheet [in "State of the Climate in 2015"]
Tedesco, M.; Box, J.; Cappelen, J. et al

in Bulletin of the American Meteorological Society (2016), 97(8),

The Greenland Ice Sheet, with the capacity to contribute ~7 m to sea level rise, experienced melting over more than 50% of its surface for the first time since the record melt of 2012.

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See detailIntercomparison of in-situ NDIR and column FTIR measurements of CO2 at Jungfraujoch
Schibig, M. F.; Mahieu, Emmanuel ULg; Henne, S. et al

in Atmospheric Chemistry and Physics (2016), 16(15), 9935--9949

We compare two CO2 time series measured at the High Alpine Research Station Jungfraujoch, Switzerland (3580 m a.s.l.), in the period from 2005 to 2013 with an in situ surface measurement system using a ... [more ▼]

We compare two CO2 time series measured at the High Alpine Research Station Jungfraujoch, Switzerland (3580 m a.s.l.), in the period from 2005 to 2013 with an in situ surface measurement system using a nondispersive infrared analyzer (NDIR) and a ground-based remote sensing system using solar absorption Fourier transform infrared (FTIR) spectrometry. Although the two data sets show an absolute shift of about 13 ppm, the slopes of the annual CO2 increase are in good agreement within their uncertainties. They are 2.04±0.07 and 1.97±0.05 ppm yr-1 for the FTIR and the NDIR systems, respectively. The seasonality of the FTIR and the NDIR systems is 4.46±1.11 and 10.10±0.73 ppm, respectively. The difference is caused by a dampening of the CO2 signal with increasing altitude due to mixing processes. Whereas the minima of both data series occur in the middle of August, the maxima of the two data sets differ by about 10 weeks; the maximum of the FTIR measurements is in the middle of January, and the maximum of the NDIR measurements is found at the end of March. Sensitivity analyses revealed that the air masses measured by the NDIR system at the surface of Jungfraujoch are mainly influenced by central Europe, whereas the air masses measured by the FTIR system in the column above Jungfraujoch are influenced by regions as far west as the Caribbean and the USA. The correlation between the hourly averaged CO2 values of the NDIR system and the individual FTIR CO2 measurements is 0.820, which is very encouraging given the largely different sampling volumes. Further correlation analyses showed, that the correlation is mainly driven by the annual CO2 increase and to a lesser degree by the seasonality. Both systems are suitable to monitor the long-term CO2 increase, because this signal is represented in the whole atmosphere due to mixing. [less ▲]

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See detailIncentives and barriers to environmental inequality mobilization: A case-study analysis in Wallonia, Belgium
Lejeune, Zoé ULg; Teller, Jacques ULg

in Environmental Science and Policy (2016)

Environmental inequality scholarship has sought to shed light on the unequal environmental conditions borne by poor people and racial minorities, and to challenge public policies. Most studies are ... [more ▼]

Environmental inequality scholarship has sought to shed light on the unequal environmental conditions borne by poor people and racial minorities, and to challenge public policies. Most studies are concerned either with assessing the unequal distribution of environmental amenities and disamenities or with exploring the theoretical foundations of environmental justice movements. We propose an original approach to environmental inequality, focused not only on the unequal distribution of environmental burdens but also on two other types of factors: the capacity to mobilize and engage in community organizations on the one hand and the spatial dimension of environmental inequalities on the other. The evidence for this study is from an opinion survey carried out in 2012 with 1298 individuals. We use a two-step cluster analysis method to compute a classification system based on four categories of variables: socio-economic, environmental, spatial, and social capital. [less ▲]

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See detailAlternative electron transport to oxygen in green microalgae during induction and steady-state photosynthesis
Franck, Fabrice ULg; de Marchin, Thomas; Fratamico, Anthony ULg et al

Conference (2016, August 06)

In this study, we used combined fluorescence-based electron transport and oxygen measurements during steady-state photosynthesis to evaluate the responses to low and high CO2 in Chlamydomonas reinhardtii ... [more ▼]

In this study, we used combined fluorescence-based electron transport and oxygen measurements during steady-state photosynthesis to evaluate the responses to low and high CO2 in Chlamydomonas reinhardtii grown in photobioreactors at different light intensities. We present a method to quantify alternative electron transport to O2 from the relationship between the apparent quantum yields of oxygen evolution and of electron transport at PSII while taking into account the variations in the proportion of energy absorbed by PSII. We used this approach to evidence a significant O2-dependent alternative electron transport in low CO2 cells. We showed that this alternative electron transport represented up to 60% of the total electron transport in low CO2 cells even when the CO2 limitation had been removed by bicarbonate addition. In contrast, no significant alternative electron transport was detected in high CO2 cells. We also analysed alternative electron transport to O2 and its relationship with the fluorescence induction process during photosynthetic induction after dark-adaptation in several microalgal species. We show that a distinct sub-phase of the fluorescence decline after the fast OJIP rise is caused by alternative electron transport to O2 and is dependent on the pre-acclimatation of the cells to different CO2 supply conditions. The involvement of mitorespiration, chlororespiration and FLV proteins in alternative electron transport to O2 is discussed on the basis of results obtained with mutants, inhibitors and FLV protein expression. [less ▲]

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See detailLes limites de la papyrologie : papyrologie et enseignement universitaire
Marganne, Marie-Hélène ULg

Conference (2016, August 05)

Which dangers is Papyrology exposed to? How to overcome these obstacles? Assets. Disadvantages. Ideas for Solutions.

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See detailOn the effect of microstructural anisotropy on the mechanical and thermophysical properties of Ti6Al4V processed by Laser Beam Melting
Mertens, Anne ULg; Paydas, Hakan ULg; Rigo, Olivier et al

Conference (2016, August 05)

Laser beam melting (LBM) is a strongly directional process in which a metallic powder is deposited layer by layer in a powder bed and molten locally according to the desired shape. When processing Ti6Al4V ... [more ▼]

Laser beam melting (LBM) is a strongly directional process in which a metallic powder is deposited layer by layer in a powder bed and molten locally according to the desired shape. When processing Ti6Al4V, it is well known that the latest layer tends to solidify epitaxially on the previous layers, thus giving rise to elongated columnar primary β(BCC) crystals extending over several successive layers. These primary β grains then transforms into the α(HCP) structure upon cooling. The present work aimed at studying the microstructural anisotropy of LBM Ti6Al4V, as well as its consequences on the mechanical and thermophysical properties (i.e. thermal expansion and thermal conductivity). In order to gain a deeper undestanding of thermal phenomena in the LBM of Ti6Al4V, great care was also taken to characterize the thermophysical properties over a wide temperature range from room temperature. [less ▲]

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See detailPlaying RPG Maker? Amateur Game Design and Video Gaming
Hurel, Pierre-Yves ULg

Conference (2016, August 04)

Game creation tools like Game Maker or RPG Maker democratize game making and facilitate the development of amateur game design. The best known among these programs have dynamic web-communities with active ... [more ▼]

Game creation tools like Game Maker or RPG Maker democratize game making and facilitate the development of amateur game design. The best known among these programs have dynamic web-communities with active members making thousands of games. However, as of now, there is little research on amateur game design except for modding or education fields. In this paper I argue that approaching amateur game making in these relations with video game playing allows a better understanding of game creation tools’ users. To support my argument, I will lean on the early results of the exploratory step of my ongoing research. [less ▲]

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See detailThe np- Control Charts with the Guaranteed In-Control Performance
Faraz, Alireza ULg; Heuchenne, Cédric ULg

E-print/Working paper (2016)

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in ... [more ▼]

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in-control average run length (ARL0) value in monitoring stage. The adjusted limits ensure that ARL0 would take a value greater than the desired value (say, B) with a certain specified probability, that is Pr⁡(ARL_0>B)=1-ρ. We finally provide users with tables which with practitioners do not need to do bootstrapping Phase I data set to obtain the control limit thresholds. [less ▲]

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See detailLes rouleaux composites répertoriés dans le Catalogue des papyrus littéraires grecs et latins du CEDOPAL
Marganne, Marie-Hélène ULg

Conference (2016, August 04)

Les rouleaux littéraires composites préfigurent-ils les codices miscellanei tels que définis par Edoardo Crisci (Segno e Testo, 2, 2004, pp. 109-144) ? Après avoir examiné les quelques exemplaires ... [more ▼]

Les rouleaux littéraires composites préfigurent-ils les codices miscellanei tels que définis par Edoardo Crisci (Segno e Testo, 2, 2004, pp. 109-144) ? Après avoir examiné les quelques exemplaires répertoriés dans le Catalogue des papyrus littéraires grecs et latins du CEDOPAL (http://cipl93.philo.ulg.ac.be/Cedopal/MP3/dbsearch.aspx), leur nature, leur présentation et l'organisation de leur contenu, on s'est interrogé sur leur contexte de production et d'utilisation en vue de répondre à cette question. [less ▲]

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See detailETUDE DE FAISABILITE DU PROJET D’ECLAIRAGE PUBLIC PAR DES LAMPADAIRES SOLAIRES DU CAMPUS 2 DE L’UNIVERSITE DE DOUALA
Koagne Nkuate, Michael; Guembou Shouop, Cébastien Joel ULg; Djaowe, Samuel

Conference (2016, August 04)

Dans le cadre de sa politique énergétique et de promotion des énergies renouvelables, le Gouvernement Camerounais, à travers le Ministère de l’Eau et de l’Energie (MINEE), a fait appel à l’expertise des ... [more ▼]

Dans le cadre de sa politique énergétique et de promotion des énergies renouvelables, le Gouvernement Camerounais, à travers le Ministère de l’Eau et de l’Energie (MINEE), a fait appel à l’expertise des sociétés « Chinoise et vietnamienne (HUAWEI), en vue de le soutenir dans le programme du développement de son potentiel énergétique. Pourtant, un certain nombre d’entreprises locales (SINTEC 3D, K&M ENGINEERING, TECHNO CAMER …) s’intéressent de plus en plus à la valorisation et à la vulgarisation des énergies renouvelables. Pour ce faire, nous avons pensé à la proposition du savoir-faire, de la disponibilité locale d’une main d’œuvre qualifiée en matière d’électrification par énergie solaire. Ceci a l’endroit des institutions, des bailleurs de fond, des ONG ainsi qu’aux autorités étatiques Camerounaises. Nous avons ainsi travaillé sur des thèmes tels que : Modèle d’électrification rurale pour localités de moins de 1000 habitants l’extrême nord Cameroun ; méthode simple de calcul et de choix des équipements solaires pour une application domestique ; ainsi que sur le thème étude de faisabilité du projet d’éclairage public par des lampadaires solaires au campus 2 de l’université de douala. C’est ainsi qu’une mission d’étude s’est rendue au sein du Campus en janvier 2016. Les détails de cette mission sont présentés dans les annexes ci-jointes. Plusieurs objectifs sont lies à cette etude: éclairer les espaces (au sein du Campus 2 de l’université de Douala) allant de l’amphi Stanislas Melonné jusqu'à la faculté des sciences passant par l’ENSET et par l’amphi George Gango par des lampadaires solaires. Le projet permettra d’accroitre la disponibilité et la sécurité de l’approvisionnement en énergie tout en valorisant et en vulgarisant les énergies renouvelables (devenu de plus en plus incontournables). Ce projet a également pour but de promouvoir les nouvelles technologies pour un développement durable du Cameroun (programme mondial des énergies propres) et de faire valoir les ressources naturelles et humaines disponibles (soleil en permanence, jeunes ingénieurs de l’ISS,…). [less ▲]

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See detailTechniques et Méthodes nucléaires : Application de la Spectrométrie Gamma au Cameroun
Moyo N., Maurice; Kayo, Steve; Ngelem M., Eric J. et al

Poster (2016, August 04)

L’imaginaire populaire est de plus en plus pessimiste au sujet du mot nucléaire, utilisées selon eux, uniquement pour détruire, en cas de guerre. Une idée reçue, mais presque imposée par l'attitude des ... [more ▼]

L’imaginaire populaire est de plus en plus pessimiste au sujet du mot nucléaire, utilisées selon eux, uniquement pour détruire, en cas de guerre. Une idée reçue, mais presque imposée par l'attitude des pays développés qui donnent l'impression de recourir au nucléaire, le plus souvent, à des fins militaires. Pourtant, les applications du nucléaire sont utiles dans des domaines aussi variés que l'agriculture, la médecine, la détection des fuites dans les barrages, la surveillance de la qualité de l'air, des eaux, des sols, des matériaux de construction, des denrées alimentaires etc. Au Cameroun, l'utilisation des rayonnements ionisants (énergie nucléaire) est en pleine croissance. Ce, spécifiquement dans les domaines médical et industriel. La radioprotection est de plus en plus l’objet des recherches et des mesures au Cameroun. Des techniques d’analyse nucléaires sont également utilisées pour déterminer les risques radiologiques lies aux rayonnements naturels provenant de l’environnement. Dans ce cadre, l’unité de recherche « Physique Fondamentale » de l’université de Douala en collaboration avec l’ANRP (Agence Nationale de RadioProtection) utilise la spectrométrie gamma pour quantifier et qualifier l’exposition des camerounais aux rayonnements. Deux mémoires de master ont à cette occasion révéler le niveau d’exposition due aux rayonnements provenant du sol de l’Université de Douala d’une part et d’autre part l’exposition due aux matériaux de construction dans la ville de Douala. Les études sur les matériaux de construction (ciment utilisé dans la ville de Douala) ont permis d’observer que l’activité spécifique dans les échantillons de ciment varie d’un radionucléide à l’autre. L’estimation des paramètres radiologiques comme (l’activité du radium équivalent Raeq, l’indice du risque externe (Hex) et interne (Hin), le taux de dose absorbée dans l’air et la dose effective annuelle (AEDE) ont montré que l’utilisation comme matériaux de construction du ciment analysé était sans risque particulier. [less ▲]

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See detailINVESTIGATION OF 238U, 235U, 137CS AND 133XE IN SOILS FROM THE UNIVERSITY OF DOUALA-CAMEROON
Ndontchueng Moyo, Maurice; Guembou Shouop, Cébastien Joel ULg; Ngelem Mekontso, Eric Jilbert et al

Conference (2016, August 04)

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