Last 7 days
Bookmark and Share    
Peer Reviewed
See detailDo tree species influence community structure and richness of Ammonia Oxidizing Bacteria at three temperate forest sites?
Malchair, Sandrine ULg; Carnol, Monique ULg

Poster (2014, July 15)

Introduction: The relationship between biodiversity and ecosystem function remains a controversial subject with numerous open questions. In Europe, the conversion of coniferous monocultures into ... [more ▼]

Introduction: The relationship between biodiversity and ecosystem function remains a controversial subject with numerous open questions. In Europe, the conversion of coniferous monocultures into broadleaved or mixed stand is considered to face ecological and economical risks posed by coniferous monocultures. Belowground effects of such a change in the dominant tree species is however largely unknown, although bacteria regulate many soil processes and some groups, like ammonia oxidizing bacteria (AOB) are highly sensitive to environmental stress. Objectives: The aims of this study were to investigate (i) AOB community structure and richness under several tree species, (ii) microbial/environmental factors related to AOB diversity, (iii) the relationship between AOB diversity and the nitrification process. Materials and methods: Forest floor (Of, Oh) was sampled under European beech, sessile oak, Norway spruce and Douglas fir at three sites. AOB community structure and richness was assessed by PCR-DGGE and sequencing. Samples were analysed for net N mineralization, potential nitrification, basal respiration, microbial biomass, microbial or metabolic quotient, pH, total nitrogen, extractable ammonium, organic matter content and exchangeable cations. Results: AOB community structure and tree species effects on AOB diversity were site-specific. Factors regulating ammonium availability, i.e. net N mineralization or microbial biomass, were related to AOB community structure. AOB richness was not related to nitrification. Conclusions: Our research revealed that, at larger spatial scales, site specific characteristics may be more important that tree species in determining AOB richness and community structure. Within sites, tree species influence AOB diversity. The absence of a relation between AOB richness and nitrification points to a possibly role of AOB abundance, phenotypic plasticity or the implication of ammonia oxidizing archaea in this process. [less ▲]

Detailed reference viewed: 35 (2 ULg)
Peer Reviewed
See detailAre expectancies and peers involved in the relation between depressive mood, anxiety and cannabis use in adolescence?
Schmits, Emilie ULg; Quertemont, Etienne ULg; Boulard, Aurore ULg

Poster (2014, July 15)

Background: Cannabis is the most commonly used illicit drug among teenagers and depression is one of the most common psychopathologies in adolescence. The specific symptom of depressive mood is present in ... [more ▼]

Background: Cannabis is the most commonly used illicit drug among teenagers and depression is one of the most common psychopathologies in adolescence. The specific symptom of depressive mood is present in 30% to 40% of adolescents in regular school settings. Links between cannabis use and depression have been highlighted, especially in adolescence. But questions remain about the strength of the association between lifetime cannabis use, depressive mood and anxiety, and about the mechanism underpinning the link. Aim: The aim of this study was to clarify the relationship between depressive mood and lifetime cannabis use in adolescents, particularly through the mediating role of anxiety and cannabis use effect expectancies, and the moderating role of peer cannabis use. Methods: A questionnaire was administered to 1,246 Belgian teenagers aged 16–17 years. ANOVA, chi-square, logistic regressions and mediation/moderation analyses were carried out to model lifetime cannabis use. Results: Depressive mood was positively correlated with lifetime cannabis use. Social anxiety, trait-anxiety and cognitive impairment effect expectancies mediated the effect of depression on lifetime cannabis use. The direct effect of depression on lifetime cannabis use increased when mediators were introduced into the relation, revealing their suppressive effects. The number of peer cannabis users moderated this model. Conclusion: Findings are discussed in terms of potential risk factors (depressive mood) or protective factors (anxiety and expectancies) for lifetime cannabis use, including the self-medication hypothesis. [less ▲]

Detailed reference viewed: 31 (9 ULg)
Full Text
See detailNumerical modelling of mirror nozzle flow
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Mercatoris, Benoît ULg et al

Conference (2014, July 15)

Detailed reference viewed: 68 (32 ULg)
Peer Reviewed
See detailModification of Conductivity, Superhydrophilicity and Photocatalytic Activity of TiO2 Thin Films Through Carbon Nanotubes Doping
Léonard, Géraldine ULg; Remy, Simon; Malengreaux, Charline ULg et al

Poster (2014, July 15)

In this work, a superhydrophilic and photocatalytic material allowing to reduce the accumulation of electrostatic charges is developed. The superhydrophilicity and photocatalytic activity of TiO2 films ... [more ▼]

In this work, a superhydrophilic and photocatalytic material allowing to reduce the accumulation of electrostatic charges is developed. The superhydrophilicity and photocatalytic activity of TiO2 films provide the “easy-to-clean” property. Indeed, superhydrophilicity induces a very low contact angle between TiO2 and water leading to the formation of a water film at the surface of the material. The photocatalytic activity, responsible for the pollutant decomposition, is explained by the excitation of the semiconductor under UV light leading to the formation of electron-hole pairs. The electrical conductivity of semiconductor TiO2 is very low leading to the accumulation of electrostatic charges and so the surface becomes a dust trap. Multi-walled carbon nanotubes (MWCNTs) are electrical conductors and their introduction in TiO2 could increase the conductivity. The incorporation of MWCNTs can modify the superhydrophilicity of TiO2. The photoactivity can be improved by reducing the electron-hole recombination rate. MWCNTs play a role in electron transfer and allow to decrease the recombination of electron-hole pairs. Two sol-gel syntheses were studied in alcohol and water respectively. In the alcoholic medium, monolayer films are obtained by dip-coating on alkaline free glass and calcined at 300, 400 or 500°C. The thermal treatment allows to crystallize TiO2 in the anatase form. In the aqueous synthesis, monolayer film are obtained by dip-coating on alkaline free glass. The TiO2 shows already the anatase structure. The characterizations of the samples have confirmed the nanotube presence in the aqueous synthesis, and in the alcoholic synthesis at 300°C and 400°C but not at 500°C. The highest conductivity is obtained from the syntheses in alcohol and the calcination at 300°C. That sample does not exhibit a high photoactivity because of its poor crystallinity. The films without MWCNTs are superhydrophilic but the contact angle increase with the incorporation of MWCNTs. The superhydrophilicity is lost with MWCNTs introduction. MWCNTs increase the roughness, the thickness and the electron transfer of the TiO2 matrix. This induces an enhancement of the photoactivity under UV. The comparison between the two syntheses shows that the alcoholic synthesis (400°C) is the best for pure film. When MWCNTs are introduced, the improvement is higher in the case of aqueous synthesis than in the case of alcoholic synthesis. The aqueous synthesis leads to more active photocatalysts than the alcoholic synthesis. [less ▲]

Detailed reference viewed: 38 (2 ULg)
Peer Reviewed
See detailStudies of early interactions among infants aged 4 to 6 months furtherly diagnosed with autistic spectrum disorder and their developmental trajectories and outcome at 4 years old.
Boulard, Aurore ULg; Wolff, Marion; Morange-Majoux, Françoise et al

Poster (2014, July 14)

The purpose of this study is to observe and analyze the social skills of infants aged 4 to 6 months later diagnosed with autism. Through the family films collected, we compared 28 children later diagnosed ... [more ▼]

The purpose of this study is to observe and analyze the social skills of infants aged 4 to 6 months later diagnosed with autism. Through the family films collected, we compared 28 children later diagnosed with autism to 28 typically developing children strictly matched on chronological age and sex. To do this, we used the social behavior assessment scale (SBAS). This scale measures the behavior of the infant (turning his head, looking, smile, vocalize ...) in response to 5 parental stimuli (1.calling by her / his name, 2.saying peek-a-boo, a vocal sound 3.Producing , 4.filmed in silent 5.simultaneous interactions with one or more persons). Then we analyzed the responses behaviors of these children with the software "the observer". Results show evidence that, contrary to infants with typical development, infants later diagnosed as autistic made less visual contact, smile or vocalize less in response to parental stimuli. However, even if the responses of autistic children are statistically different in quantity (compared to the control group), responses to parental stimuli are still present. In a second step, we studied the developmental trajectories of children with autism. Our hypothesis was that children with a low score at the SBAS would have a lower global development score than the children with a high score at the SBAS at 3 years old. Our results validate our hypothesis. [less ▲]

Detailed reference viewed: 47 (4 ULg)
Full Text
See detailHigher Symmetries of the conformal Laplacian
Radoux, Fabian ULg

Conference (2014, July 14)

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
See detailSelf broadening coefficients and improved line intensities for the ν7 band of ethylene near 10.5 µm, and impact on ethylene retrievals from Jungfraujoch spectra
Vander Auwera, J; Fayt, A; Tudorie, M et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2014), 148

Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self broadening coefficients for the nu7 band of ... [more ▼]

Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self broadening coefficients for the nu7 band of 12C2H4. The measured self broadening coefficients exhibit a dependence on both J and Ka. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10 % for high J lines in the P branch and lower by about 5 % for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrievals of atmospheric ethylene in the 949.0-952.0 cm-1 microwindow was evaluated using a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The use of HITRAN 2012 with line intensities modified to match the present measurements led to a systematic reduction of the measured total columns of ethylene by -4.1+/-0.1 %. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Full Text
See detailLe Comité permanent R dans sa relation avec le Parlement et certains acteurs du pouvoir exécutif : cohérence ou incohérence?
Stans, David ULg

Doctoral thesis (2014)

Il est possible d’envisager dans un Etat démocratique, bien que de manière un peu restrictive, que les deux grandes formes de contrôle traditionnelles opérées sur les services de renseignement (efficience ... [more ▼]

Il est possible d’envisager dans un Etat démocratique, bien que de manière un peu restrictive, que les deux grandes formes de contrôle traditionnelles opérées sur les services de renseignement (efficience et légalité) peuvent s’exercer, de manière très générale, suivant cinq axes différents : interne (hiérarchique), exécutif (tutelle ministérielle), externe (avec une composante parlementaire), judiciaire et médiatique/société civile. Chaque axe peut être composé ou se subdiviser en divers mécanismes qui agissent parfois dans une temporalité différente. Le recours à un Comité indépendant et externe tend à répondre aux dysfonctionnements des services (interne, coordination, rétention d’information, dépassement de compétences, etc.) et au manque de capacité tant pour le Parlement que pour l’Exécutif, de mettre en œuvre leurs prérogatives dans cette matière. Il est théorique admis que pour être véritablement démocratique, le contrôle de la gouvernance du renseignement doit comporter une composante parlementaire. C’est donc à ces acteurs que nous nous sommes intéressés. Le choix a été fait en Belgique de recourir à un organe externe chargé, dans sa mission générale, de surveiller le respect des Droits et Libertés des citoyens par les services et l’Ocam mais aussi leur efficience et coordination au profit et dans le respect des compétences de certains acteurs. L’objectif du Comité n’est donc pas de remplacer les autres acteurs. Ce contrôle doit, dans sa mission générale, permettre aux acteurs de jouer leur rôle (sans les remplacer) et conduire ainsi à la réalisation d’un véritable contrôle démocratique favorisant la responsabilité de la gouvernance du renseignement tout en respectant un équilibre indispensable secret et ouverture. Nous avons donc chercher à savoir si permettre l’intervention de certains acteurs de l’Exécutif dans un mécanisme indépendant et externe, d’une certaine manière rattaché au parlement est cohérent ou non ? [less ▲]

Detailed reference viewed: 37 (9 ULg)
Full Text
Peer Reviewed
See detailStudy of the specific interaction between Fluorescent PDMAEMA and human Platelets
Flebus, Luca ULg; Lombart, François ULg; Martinez, Lucia et al

Conference (2014, July 12)

Hemoreactivity of the poly (2-(dimethylamino) ethylmethacrylate) polymer (PDMAEMA) under a free form (thus not as a “PolyElectrolyte Complex”) was assessed. In order to facilitate the in vitro monitoring ... [more ▼]

Hemoreactivity of the poly (2-(dimethylamino) ethylmethacrylate) polymer (PDMAEMA) under a free form (thus not as a “PolyElectrolyte Complex”) was assessed. In order to facilitate the in vitro monitoring of this polycation and especially to follow its reactivity blood we have labeled it with fluorescein adopting a new chemical route of synthesis. Unexpectedly, using flow cytometry, this study showed a higher affinity of PDMAEMA for platelets than for red blood cells. [less ▲]

Detailed reference viewed: 16 (3 ULg)
Full Text
See detailOptimization of the service start time for an elementary shortest path problem with time windows
Arda, Yasemin ULg; Crama, Yves ULg; Kucukaydin, Hande ULg

E-print/Working paper (2014)

We investigate an elementary shortest path problem with resource constraints where a single capacitated vehicle, initially located at a depot, must serve a set of customers while respecting their ... [more ▼]

We investigate an elementary shortest path problem with resource constraints where a single capacitated vehicle, initially located at a depot, must serve a set of customers while respecting their individual time windows. When the vehicle visits a customer, it delivers the customer's demand and collects a revenue in return for the delivery. The vehicle can start its trip at any desired time. The transportation cost is a function of both the total distance traveled and the duration of the assigned trip. The objective is to determine the service start time from the depot, the subset of customers to be served, and the trip to be performed so as to minimize the total loss, which is calculated as the di erence between the transportation cost and the revenue collected from the customers. We develop two exact dynamic programming algorithms which can deal with an in nite number of Pareto-optimal states arising from the fact that the starting time and the duration of the trip act like continuous decision variables. We report computational results obtained with these algorithms and with a faster heuristic for the elementary shortest path problem. We also examine the performance of these algorithms when they are used to solve the pricing subproblem arising in the framework of a column generation algorithm for a related vehicle routing problem with time windows. [less ▲]

Detailed reference viewed: 149 (8 ULg)
Full Text
See detailTowards a better understanding of time-lapse electrical resistivity properties associated to organic contaminants and bioremediation processes in the subsurface
Caterina, David ULg

Doctoral thesis (2014)

Management of contaminated sites represents a major problem for our society. Geophysical methods arise progressively as non-conventional techniques that should allow decreasing the uncertainty linked to ... [more ▼]

Management of contaminated sites represents a major problem for our society. Geophysical methods arise progressively as non-conventional techniques that should allow decreasing the uncertainty linked to the local nature of punctual drilling/sampling measurements classically used to identify, characterize and monitor such sites. However, the use of geophysics for this purpose is relatively recent and still requires an improvement of geophysical imaging and a better understanding of the impact of contaminants and remediation processes on measured properties to be fully effective. The main objective of this thesis was thus to improve our knowledge on these two aspects. In order to assess the reliability of geophysical imaging, and electrical resistivity tomography (ERT) in particular, we first compare quantitatively different image appraisal indicators. The latter are developed to detect artefacts, estimate depth of investigation, address parameters resolution and appraise ERT-derived geometry. Numerical benchmarks are created representing different geological situations in terms of heterogeneity and scale. On the basis of this comparison, we propose a methodology and guidelines to appraise both qualitatively and quantitatively field ERT images. We show the successful applications on real data coming from the contaminated sites we investigated. It notably allows us to exclude from our interpretation zones of the electrical images that are not considered as sufficiently reliable. To enhance electrical imaging, we investigate three different approaches to incorporate prior information into the ERT inverse problem, namely reference model, structural constraint and regularized geostatistical inversion that we notably apply on real data coming from two contaminated sites. The results are benchmarked against the standard smoothness constraint inversion. Results with real data show that adding prior information in the inversion process always lead to a modification of the solution at least in zones of low sensitivity (allowing notably to better image contaminant plumes at depth). However, the choice of the constraint to apply is highly dependent on the type and amount of information available. Therefore, we provide guidelines that should help the practitioner to include their prior information directly into the inversion process through an appropriate way. To understand the temporal geoelectrical signature of organic contaminants and bioremediation processes, we monitor a site contaminated with hydrocarbons and subjected to stimulated bioremediation. We first show that the most contaminated areas above the groundwater table level are associated to very low resistivities. We then show that during biostimulation (promoting aerobic degradation) and natural attenuation, observed resistivity variations (up to 140%) are mostly located in the saturated zone of the contaminated area. They follow a seasonal trend suggesting a temperature dependence not observed in an uncontaminated zone of the site. However, in the contaminated area, changes largely exceed the expected variations due only to the temperature. We therefore investigate systematically different hypotheses that may explain such changes. Among those hypotheses, we show that microbial activity is a factor that may potentially influence the electrical signature of a contaminated soil and may contribute to the observed resistivity changes. In order to further study the electrical response associated to bacterial activity during bioremediation processes, we monitor a tank experiment that contains soils contaminated with hydrocarbons subjected first to biostimulation and then to bioaugmentation (with an inoculum of Rhodococcus erythropolis T902.1). Whereas no particular electrical signature is observed during the biostimulation phase, we observe a correlation between the evolution of bulk resistivity changes and the specific oil-degrading flora after bioaugmentation that cannot be attributed to fluid resistivity changes. This suggests a direct impact of microbial growth/activity on electrical properties through the modification of surface and/or local electrolytic conduction mechanisms. These latter results open up new perspectives for future experiments that should involve spectral induced polarization measurements allowing a better discrimination between the two conduction mechanisms. [less ▲]

Detailed reference viewed: 46 (15 ULg)
Peer Reviewed
See detailCompeting One-Way Essential Complements : the Forgotten Side of the Net Neutrality Story
Broos, Sébastien ULg; Gautier, Axel ULg

Conference (2014, July 11)

We examine the incentives of an internet service provider (ISP) to break net neutrality by excluding internet applications competing with its own products, a typical example being the exclusion of VoIP ... [more ▼]

We examine the incentives of an internet service provider (ISP) to break net neutrality by excluding internet applications competing with its own products, a typical example being the exclusion of VoIP applications by a telecom company offering internet and voice services. We show that exclusion is not a concern when the ISP is a monopoly because it can extract the additional surplus created by the application through price rebalancing. By contrast, when ISP’s compete, in an attempt to differentiate, only one ISP will offer the app. Applying a no-exclusion rule in this case can lead to monopoly. [less ▲]

Detailed reference viewed: 24 (5 ULg)
Full Text
Peer Reviewed
See detailEffect of lignocellulose related compounds on microalgae growth and product biosynthesis: a review
Miazek, Krystian ULg; Remacle, Claire ULg; Richel, Aurore ULg et al

in Energies (2014), 7(2014), 4446-4481

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates ... [more ▼]

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated. [less ▲]

Detailed reference viewed: 50 (26 ULg)
Full Text
See detailMicellization of PEO-b-polyphosphate for drug delivery applications
Vanslambrouck, Stéphanie ULg; Clément, Benoit; Riva, Raphaël ULg et al

Conference (2014, July 11)

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailA formulation on the special Euclidean group for dynamic analysis of multibody systems
Sonneville, Valentin ULg; Bruls, Olivier ULg

in Journal of Computational and Nonlinear Dynamics (2014), 9(4), 041002

Detailed reference viewed: 28 (4 ULg)
Full Text
Peer Reviewed
See detailDiversity of Bacterial Communities in a Profile of a Winter Wheat Field: Known and Unknown Members
Stroobants, Aurore ULg; Degrune, Florine ULg; Olivier, Claire et al

in Microbial Ecology (2014)

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known ... [more ▼]

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known about the distribution and composition of bacterial communities through the soil profile, particularly in agricultural soils, as most studies have focused only on topsoils or forest and grassland soils. In the present work, we have used bar-coded pyrosequencing analysis of the V3 region of the 16S rRNA gene to analyze bacterial diversity in a profile (depths 10, 25, and 45 cm) of a well-characterized field of winter wheat. Taxonomic assignment was carried out with the Ribosomal Database Project (RDP) Classifier program with three bootstrap scores: a main run at 0.80, a confirmation run at 0.99, and a run at 0 to gain information on the unknown bacteria. Our results show that biomass and bacterial quantity and diversity decreased greatly with depth. Depth also had an impact, in terms of relative sequence abundance, on 81 % of the most represented taxonomic ranks, notably the ranks Proteobacteria, Bacteroidetes, Actinobacteridae, and Acidobacteria. Bacterial community composition differed more strongly between the topsoil (10 and 25 cm) and subsoil (45 cm) than between levels in the topsoil, mainly because of shifts in the carbon, nitrogen, and potassium contents. The subsoil also contained more unknown bacteria, 53.96 % on the average, than did the topsoil, with 42.06 % at 10 cm and 45.59 % at 25 cm. Most of these unknown bacteria seem to belong to Deltaproteobacteria, Actinobacteria, Rhizobiales, and Acidobacteria. [less ▲]

Detailed reference viewed: 36 (17 ULg)
Full Text
See detail(Wrong) representations of physical activity, from definition to recommandations
Cloes, Marc ULg

Conference (2014, July 10)

Faisant partie intégrante de notre vie quotidienne, l’activité physique et la sédentarité constituent deux notions qui s’opposent dans la conception d’un style de vie sain. Les recherches actuelles ... [more ▼]

Faisant partie intégrante de notre vie quotidienne, l’activité physique et la sédentarité constituent deux notions qui s’opposent dans la conception d’un style de vie sain. Les recherches actuelles montrent que chacune d’elles devrait faire l’objet d’une attention particulière. Toutefois, qu’ils fassent partie du grand public ou appartiennent à des professions liées à la santé, il apparait que les individus ne construisent pas toujours des représentations adéquates à propos des bonnes habitudes de vie. Dans la perspective d’influencer favorablement la culture des citoyens en matière d’activité physique, il s’avère donc nécessaire de rappeler régulièrement les informations clés qui devraient être retenues et appliquées dans la vie de tous les jours. Afin d’illustrer la manière avec laquelle les représentations peuvent constituer le fil rouge d’un processus amenant les gens à adopter un style de vie physiquement actif et peu sédentaire, nous passerons brièvement en revue la définition de l’activité physique, l’identification de ses effets et les recommandations proposées actuellement par les agences de santé publique. Nous utiliserons différentes approches ludiques originales, susceptibles de faire vivre aux participants des expériences visant à stimuler le traitement des informations et à privilégier leur rétention. Au niveau de la définition de l’activité physique, l’objectif consistera à faire ressortir les différentes dimensions de l’activité physique. Puisque les recherches les plus récentes en soulignent l’incidence de plus en plus marquée, nous insisterons également sur la distinction entre les différents niveaux d’intensité de la pratique. Ensuite, une classification des effets bénéfiques de l’activité physique sera proposée avant une révision des recommandations internationales. Les modalités de présentation originales qui seront mises en place stimuleront la prise de conscience de certaines mauvaises représentations, courantes dans le public. La dernière partie de l’exposé consistera à illustrer les contre-arguments à opposer à ceux qui ne sont pas encore convaincus qu’ils pourraient bouger davantage. [less ▲]

Detailed reference viewed: 23 (0 ULg)
Full Text
Peer Reviewed
See detailSelf broadening coefficients and improved line intensities for the n7 band of C2H4 near 10.5 mm, and impact on ethylene retrievals from Jungfraujoch solar spectra
Vander Auwera, Jean; Fayt, André; Tudorie, Marcela et al

Poster (2014, July 10)

Ethylene (ethene, C2H4) is a tropospheric pollutant on the Earth, also present as a by-product of methane photochemistry in the atmosphere of outer solar system bodies. Remote sensing of ethylene in the ... [more ▼]

Ethylene (ethene, C2H4) is a tropospheric pollutant on the Earth, also present as a by-product of methane photochemistry in the atmosphere of outer solar system bodies. Remote sensing of ethylene in the infrared range relies on the 10 mm region. This spectral range corresponds to the excitation of 7 modes of vibration of 12C2H4, 4 of which being infrared active (see Fig. 1 of [1]). The corresponding n10, n7, n4 and n12 bands are located near 826, 949, 1026 and 1442 cm-1, respectively [1]. Among these, the n7 band is the strongest, indeed used for remote sensing measurements of ethylene. Relying on high-resolution Fourier transform infrared (FTIR) spectra recorded in Brussels, the present work involved extensive measurements of individual line intensities and self broadening coefficients for the n7 band of 12C2H4. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database (HITRAN 2012 [2]), the measured line intensities were found to be higher by about 10 % for high J lines in the P branch and lower by about 5 % for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. Test calculations performed in this work indicated that these discrepancies could result from the relative values of the transition moments of the n10, n7 and n12 bands used when the information provided in HITRAN was generated (the transition moment of the n4 band was set to zero). The measured self broadening coefficients exhibit a dependence on both J and Ka, which was modeled empirically. The spectroscopic information for ethylene available in HITRAN 2012 was modified to match the present observations. The impact of these modifications on retrievals of atmospheric ethylene was then evaluated via FTIR retrievals in the 949.0 – 952.0 cm-1 microwindow, from a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The new line intensities were found to lead to a reduction of the measured total columns of ethylene by -4.1±0.1 %, compared to the use of HITRAN 2012. [less ▲]

Detailed reference viewed: 18 (2 ULg)
Full Text
See detailOutils d’étude pour caractériser l’impact de l’ hydrodynamique sur la culture de cellules animales adhérentes cultivées sur microporteurs en bioréacteurs à cuve agitée
Collignon, Marie-Laure ULg

Conference (2014, July 10)

Cette présentation montre l'importance du choix des conditions d'agitation lors de la culture de cellules animales adhérentes sur microporteurs en bioréacteurs à cuve agitée. Elle montre des exemples d ... [more ▼]

Cette présentation montre l'importance du choix des conditions d'agitation lors de la culture de cellules animales adhérentes sur microporteurs en bioréacteurs à cuve agitée. Elle montre des exemples d'outils pour caractériser à l'échelle locale l'hydrodynamique au sein de ces bioréacteurs et une approche Euler-Lagrange qui a terme permettra de faire le lien entre l'hydrodynamique et la réponse cellulaire grâce à l'établissement de l'historique de conditions rencontrées localement par les cellules. [less ▲]

Detailed reference viewed: 15 (5 ULg)