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See detailA wavelet leaders-based climate classification of European surface air temperature signals
Deliège, Adrien ULg; Nicolay, Samuel ULg

Conference (2014, June 25)

We present the wavelet leaders method as a tool to study the pointwise regularity of signals, which is closely related to some functional spaces. We use the associated multifractal formalism to show that ... [more ▼]

We present the wavelet leaders method as a tool to study the pointwise regularity of signals, which is closely related to some functional spaces. We use the associated multifractal formalism to show that the surface air temperature signals are monofractal, i.e. these are regularly irregular. Then we use this result to establish a climate classification of weather stations in Europe which matches the Köppen-Geiger climate classification. This result could give rise to new criteria to determine the effectiveness of current climatic models. [less ▲]

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See detailA wavelet leaders-based climate classification of European surface air temperature signals
Deliège, Adrien ULg; Nicolay, Samuel ULg

in Ruiz Garcia, Gonzalo; Rojas Ruiz, Ignacio (Eds.) Proceedings of the International work-conference on Time Series: Volume 1, Granada 25-27 June 2014 (2014, June 25)

We explain the wavelet leaders method, a tool to study the pointwise regularity of signals, which is closely related to some functional spaces. We use the associated multifractal formalism to show that ... [more ▼]

We explain the wavelet leaders method, a tool to study the pointwise regularity of signals, which is closely related to some functional spaces. We use the associated multifractal formalism to show that surface air temperature signals are monofractal, i.e. these climate time series are regularly irregular. Then we use this result to establish a climate classification of weather stations in Europe which matches the Köppen-Geiger climate classification. This result could give rise to new criteria to determine the efficiency of current climatic models. [less ▲]

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See detailEfficacy of seed extracts of Annona squamosa and Annona muricata (Annonaceae) for the control of Aedes albopictus and Culex quinquefasciatus (Culicidae)
Raveloson Ravaomanarivo, Lala Harivelo; Andrianiaina Razafindraleva, Herisolo; Raharimalala, Fara Nantenaina ULg et al

in Asian Pacific Journal of Tropical Biomedicine (2014), 4(10), 787-795

Objective: To evaluate the potential efficacy of seed extracts of Annona squamosa and Annona muricata used as natural insecticides to control adult and larvae of the vectors Aedes albopictus and Culex ... [more ▼]

Objective: To evaluate the potential efficacy of seed extracts of Annona squamosa and Annona muricata used as natural insecticides to control adult and larvae of the vectors Aedes albopictus and Culex quinquefasciatus under laboratory conditions. Methods: Aqueous and oil extracts of the two plants were prepared from dried identifications of the chemical components of each seed extracts were performed using microreactional and GCP Technique. Larvea and adults of Aedes albopictus and Culex quinquefasciatus were collected for the breeding sites in coastal and highlands regions of Madagascar. WHO standardized tests of susceptibility for larvae and imaginal stage of mosquitoes were realized to 50 of mosquitoes. Results: Chemical identifications showed that these extracts contain alkaloids and flavonoids compounds that probably confer their biological insecticidal propriety. CPG analysis showed also the presenceof various fatty acids. On adults mosquitoes, significant insecticidal effects were observed with both aqueous and oil extracts of the two plant seeds compared to mortality induced by deltamethrin, an insecticide used as reference. Extracts of Annona muricata induced high mortality rate to both species of mosquito compared to extracts of Annona squamosa at all concentrations 50 of seed extracts ranged from 1% to 5% for adults and 0.5% to 1% for larvae. Conclusions: The seed extracts of these two plants may be used as mosquito controlling agents and offer a new approach to a less costly, pratical and environmentally friendly control of vector borne diseases. [less ▲]

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See detailQuelles marges budgétaires pour relancer la Wallonie?
Piron, Damien ULg

Article for general public (2014)

Le PS et le cdH négocient actuellement la formation du gouvernement de la Région wallonne. Il y a fort à parier que ces deux partis chercheront à poursuivre la stratégie de redéploiement économique ... [more ▼]

Le PS et le cdH négocient actuellement la formation du gouvernement de la Région wallonne. Il y a fort à parier que ces deux partis chercheront à poursuivre la stratégie de redéploiement économique amorcée il y a une quinzaine d’années au travers du Contrat d’Avenir pour la Wallonie et prolongée dans deux versions successives du Plan Marshall. De récents développements dans le champ de la comptabilité publique risquent toutefois de contraindre le prochain exécutif régional à de douloureux arbitrages budgétaires. [less ▲]

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See detailVehicle routing problems with multiple trips: using specific local search operators
Arda, Yasemin ULg; Crama, Yves ULg; François, Véronique ULg et al

Conference (2014, June 25)

In vehicle routing problems with multiple trips (VRPM), each vehicle is allowed to perform more than one trip during its working period. Classical solution techniques for this problem make use of existing ... [more ▼]

In vehicle routing problems with multiple trips (VRPM), each vehicle is allowed to perform more than one trip during its working period. Classical solution techniques for this problem make use of existing VRP heuristics to create trips, together with bin packing methods aimed at assigning these trips to the available vehicles. The first contribution of this work is to propose specific local search operators for the VRPM. The operators directly integrate the multi-trip structure of the problem within well-known VRP operators. As a second contribution, heuristics using these operators are compared with classical solution techniques mentioned above. The comparison is performed by using the adaptive large neighborhood search metaheuristic as a common basis for both methods. The most classical version of the problem is studied as well as a variant involving time windows [less ▲]

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See detailTurning land to livelihood : what are the socio-economic and institutional determinations of local land use in Red River Delta region ?
Nguyen Thi, Dien; Lebailly, Philippe ULg; Vu Dinh, Ton

Conference (2014, June 24)

This research analyzes the determinations of household land use strategy in the context of the rapid rural changes due to the industrialization and urbanization in Vietnam. The mechanism that turns land ... [more ▼]

This research analyzes the determinations of household land use strategy in the context of the rapid rural changes due to the industrialization and urbanization in Vietnam. The mechanism that turns land to livelihood from both productive and non-productive processes is investigated to understand the different land use strategies of smallholders in Red River Delta region. Based on the presence of migrating members, the total selected 191 households in Hai Duong province were divided into 3 different groups to do the surveys. The research results show that local land use strategies are various in which 79.06% of surveyed households maintain the allocated land for agricultural production while 65.97% of households leave land idly at least once a year. The factors from productive process such as small landholding, high production cost and overall downward income from agricultural production meantime the greater opportunities from non-farm jobs are the main socio-economical determinations of agricultural land abandonment or less effective use. The security questions of shifting livelihood between farming and non – farming sectors, the inter-household arrangements, the social supports and the institutional constraints are non-productive elements that make the exchange and other forms of commercializing agricultural land are less prominent. The complexity of household land use strategy and its determinations not only reflects the dynamism and flexibility of peasant’s livelihood adaptation but also explain why the land concentration does not proceed faster in Red River Delta region of Vietnam. [less ▲]

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See detailDo it like Andhra Pradesh
Maiorano, Diego ULg

Article for general public (2014)

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See detailCalculation of third order joint acceptance function for line-like structures
Blaise, Nicolas ULg; Canor, Thomas ULg; Denoël, Vincent ULg

Scientific conference (2014, June 24)

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See detailProbing the conformational changes during desolvation of ions using orthogonal mobility methods (CE-IM MS)
Far, Johann ULg; Kune, Christopher ULg; Delvaux, Cédric ULg et al

Poster (2014, June 24)

Routine analyses using Mass Spectrometry (MS) detection became a very popular due to the low limit of detection, great sensitivity, selectivity and specificity. Moreover MS enables structural elucidation ... [more ▼]

Routine analyses using Mass Spectrometry (MS) detection became a very popular due to the low limit of detection, great sensitivity, selectivity and specificity. Moreover MS enables structural elucidation and physical (or physicochemical) properties determination using low amount of not especially pure samples. One of these properties is substantially the stoichiometry determination of non-covalent complexes such as Ligand receptor systems (e.g. DNA-drugs, Hormones/drugs-receptor, quaternary structure arrangement of polypeptides, …). MS determination in native condition (Native MS) of this stoichiometry allows large scale screening of potential drugs candidates in pharmaceutical context. The addition of Ion-Mobility (IM) to mass spectrometry (IM-MS) with computational chemistry support allows the structural conformation monitoring (as Collisional Cross Section or CCS) and the elucidation of interactions of the non-covalent complexes. Nonetheless such determinations suppose/assume that desolvation steps and gas phase transfer during MS detection do not modify the tridimensional structure of these systems or the magnitude order of the involved interactions (dipole-dipole, dipole-ion, ion-ion, hydrophobic interactions). Further studies (Circular Dichroism, Nuclear Magnetic resonance, UV-Visible spectra …) are generally required to confirm the MS data but there are unfortunately time consuming. This project proposes the coupling of Capillary Electrophoresis (CE) to IM-MS in order to obtain in one injection the quantitative and qualitative data of non-covalent complexes and the monitoring of tridimensional conformation modification between the liquid and gas phase. Indeed CE allows the determination of numerous physicochemical properties (dissociation constant, pK values, hydrodynamic radius determination …). The structural data (i.e. hydrodynamic radius and CCS) are compared to the data obtained by IM-MS as a proof of concept using tryptic digest of Bovine Serum Albumine (BSA). [less ▲]

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See detailSequential decision making under uncertainty in randomly generated games : A Minecraft intelligent agent for resource gathering
Lorent, Pierre ULg

Master's dissertation (2014)

Video games have significantly evolved since the emergence of first arcade games. They have become more and more complex and now allow for the simulation of advanced environments. This work focuses on the ... [more ▼]

Video games have significantly evolved since the emergence of first arcade games. They have become more and more complex and now allow for the simulation of advanced environments. This work focuses on the development of an intelligent agent that aims at collecting a given type of ressource in random worlds from Minecraft, a well-known video game. [less ▲]

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See detailQualité de vie et poursuite de buts à l’adolescence : une approche qualitative
TILKIN, Caroline; Lejeune, Christophe ULg; Etienne, Anne-Marie ULg

Scientific conference (2014, June 24)

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See detailA Phylogenomic analysis of the origin of plastids
Cornet, Luc ULg; Javaux, Emmanuelle ULg; Wilmotte, Annick ULg et al

Conference (2014, June 24)

Cyanobacteria are a morphologically diverse phylum, with their first occurrence dating from the Precambrian. Oxygenic photosynthesis appeared in this group during the same geological period. Several ... [more ▼]

Cyanobacteria are a morphologically diverse phylum, with their first occurrence dating from the Precambrian. Oxygenic photosynthesis appeared in this group during the same geological period. Several publications have established, without any doubt, that plastids (both primary and complex) form a monophyletic ensemble emerging from Cyanobacteria. However, the exact position of plastids within Cyanobacteria is still uncertain, with several recent papers leading to very different hypotheses. Here we present a phylogenomic analysis of the origin of plastids. Our study takes advantage of all the available genomes and thus represents the best taxonomic sampling seen so far: 140 genomes of Cyanobacteria, 101 genomes of plastids and 27 outgroups taken in Melainabacteria and Chloroflexi. It results in an analysis using state-of-the-art methods (e.g., orthology assessment using USEARCH and OrthoMCL, phylogenetic inference using CAT and CAT-GTR models) based on more than 160 protein alignments totalizing over 20,000 unambiguously aligned amino acids. To confirm our results, we performed gene jackknife inferences and gene reconciliation analyses on the same dataset. We expect that out approach accounts for potential phylogenetic artefacts due to changes in the evolutionary process having occurred when the guest cyanobacterium became an endosymbiont and eventually a plastid. Meanwhile, we improve the phylogeny of Cyanobacteria per se, notably because of the presence of Melainabacteria in our dataset. [less ▲]

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See detailStandardisation of 25(OH)-vitamin D assays: beware of limitations
CAVALIER, Etienne ULg

Conference (2014, June 24)

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See detailBodies of Evidence: An Anthropology of the Health Claim
Hendrickx, Kim ULg

Doctoral thesis (2014)

How can a food or food ingredient be proven healthy, without calling it a drug? In this thesis, I make an attempt at understanding the stakes of a heated debate involving scientists from the food industry ... [more ▼]

How can a food or food ingredient be proven healthy, without calling it a drug? In this thesis, I make an attempt at understanding the stakes of a heated debate involving scientists from the food industry, academia, and the European regulatory authorities. The centrality and importance of 'science' in the debate is remarkable, and merits our full attention. The 'science' that is disputed between 'industry' and 'the regulatory authorities', and that serves as a vehicle for their credibility and authority respectively, consists of a very particular practice of putting molecules to the test in clinical trials. The clinical trial in drug testing allows for making a qualitative leap from a molecule's biological action to its therapeutic effect. In the case of food, it is not permitted to define the molecule's therapeutics in relation to pathology, otherwise the substance tips over and becomes a drug. The shared concern of all scientists involved in the debate is to avoid this 'tipping point'. What the debate shows, is not so much an opposition between 'corporate science' and 'regulatory science', but an uneasy relationship between the ecology of pharmaceutical drugs, and an ecology-yet-to-be-made for food therapeutics. Such an ecology rests upon a pattern of collaboration -or agencement- between materials and humans pertaining to different realms of production, regulation and science. As such, the terms of the debate on healthy food ingredients can be reformulated in more precise terms than 'industry' versus 'the authorities', or 'good science' versus 'bad science', which only come to exacerbate a deeper-lying tension that is technical and political at once. At stake are our conceptions of health and disease, cure and prevention, and the professionals that have the authority to talk about health in present-day Europe. [less ▲]

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See detailDevelopment of a multiplexed surface-enhanced Raman scattering quantitative approach for bisphenols detection
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Sacre, Pierre-Yves ULg et al

Conference (2014, June 23)

Over the last decade, bisphenol A (BPA) attracted a lot of attention. This molecule, commonly used as a precursor to produce epoxy-resin and plastics, is an endocrine disruptor presenting an estrogenic ... [more ▼]

Over the last decade, bisphenol A (BPA) attracted a lot of attention. This molecule, commonly used as a precursor to produce epoxy-resin and plastics, is an endocrine disruptor presenting an estrogenic activity [1]. Despite its health toxicity, BPA is present in a broad variety of consumer goods released from plastic bottles and packaging for example. Since the discovery of its adverse health effect of BPA, the manufacturers tend to use structural analogues of BPA such as BPS, BPF and BPB to produce plastic materials [2]. However, the health safety of these molecules is still not demonstrated. Currently, bisphenols are actively researched and quantified using solid phase extraction and chromatography techniques which are time and solvents consuming. Therefore, it could be very interesting to quantify simultaneously bisphenols using a fast and “green” technique. Surface-enhanced Raman scattering (SERS) exalts dramatically the Raman scattering of molecules adsorbed or very closed to metallic surface enabling to detect very low amounts of analytes while keeping the structural information obtained from the spectrum which is very interesting to consider multiplexed analyses [3-4]. Moreover, SERS, which is a solvent free and fast acquisition technique, is an attractive tool in “Green Chemistry” [5]. In this context, the development of a multiplexed quantitative approach to detect bisphenol was considered. Silver nanoparticles (AgNps) were selected as SERS substrate and their functionalization was investigated taking into account the weak affinity of phenolic molecules for gold and silver surface [6]. Pyridine was selected as surface modifier and allowed to attract bisphenols around metallic surface thanks to hydrophobic interaction and hydrogen bonds [7]. Afterwards, the SERS samples preparation was optimized playing on the concentrations of pyridine and aggregating agent used to get the nanoparticles closer to each other which promotes the SERS effect. Tap water samples were spiked with different concentration of BPA from 5 ppb to 1000 ppb and analyzed using the optimized SERS sample preparation. A good linearity of the response was observed and a calibration curve with coefficient of determination (R2) of 0.9922 was obtained by plotting the intensity of a principal band of BPA versus the concentration. This last step was repeated using BPB as analyte and a calibration curve with a R2 of 0.9991 was obtained for the same range of concentration using a specific band intensity of BPB. Finally, tap water samples were spiked with different concentrations of BPA and BPB simultaneously and analyzed using SERS and it was possible to detect selectively the two molecules thanks to specific bands and a good linearity of the response was observed for both. To conclude, promising results were obtained which pave the way to “green” multiplexed quantitative analyses of very low concentrated analytes using SERS. References: [1] J.-H. Kang et al., Toxicology 226 (2006) 79-89 [2] C. Liao et al., J. Agric. Food Chem. 61 (2013) 4655-4662 [3] K. Kneipp et al., Chem. Rev. 99 (1999) 2957-2975. [4] R.F. Aroca et al., Adv.Colloid Interface Sci. 116 (2005) 45-61. [5] C. De Bleye et al., Talanta 116 (2013) 899-905. [6] X.X. Han et al., Anal. Chem., 83 (2011) 8582-8588. [7] B. San Vicente et al., Anal. Bioanal. Chem. 380 (2004) 115-122. [less ▲]

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See detailChemical abundances of fast-rotating OB stars
Cazorla, Constantin ULg; Morel, Thierry ULg; Nazé, Yaël ULg et al

Poster (2014, June 23)

Fast rotation in massive stars is predicted to induce mixing in their interior, but recent observations have challenged this concept by revealing a population of fast-rotating stars with normal nitrogen ... [more ▼]

Fast rotation in massive stars is predicted to induce mixing in their interior, but recent observations have challenged this concept by revealing a population of fast-rotating stars with normal nitrogen abundances at their surface (Hunter et al. 2009, A&A, 496, 841; Brott et al. 2011, A&A, 530, A116, but see Maeder et al. 2014, A&A, 565, A39). However, as the binary fraction of these stars is unknown, the importance of mass-transfer processes cannot be quantified. As a result, no definitive statements about the ability of single-star evolutionary models including rotation to reproduce these observations can be made. Our work combines for the first time a detailed surface abundance analysis with a radial-velocity monitoring for a sample of bright, fast-rotating Galactic OB stars to put strong constraints on stellar evolutionary and interior models. [less ▲]

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See detailAlteration of decoherence-free states caused by dipole-dipole interactions
Damanet, François ULg; Martin, John ULg

Poster (2014, June 23)

Decoherence, known as the consequence of the coupling of any quantum system to its environment, causes information loss in the system and represents a major problem in the physical realization of quantum ... [more ▼]

Decoherence, known as the consequence of the coupling of any quantum system to its environment, causes information loss in the system and represents a major problem in the physical realization of quantum computers [1]. Decoherence-Free States (DFS) are considered as a possible solution to this problem. A set of trapped cold atoms placed in a DFS state will be immune against decoherence due to spontaneous emission. However, because of dipole-dipole interactions between atoms, induced dephasing effects are likely to destroy the coherence and drive the system out of its DFS [1, 2]. In this work, we study numerically the dynamics of a set of two-level atoms initially in a DFS with respect to dissipative processes by solving the master equation including both dissipative dynamics and dipole dipole interactions. We fo- cus our attention on the infuence of dipolar coupling on the radiated energy rate and coherence of the system as in [3]. In particular, by averaging over many realizations of close randomly distributed atomic positions, we show the formation of a superradiant-like pulse and we study its properties as a function of the dipolar coupling strength. [1] D. A. Lidar & K. B. Whaley, Lectures Notes in Phys., Vol. 622, p83-120, Springer (2003). [2] M. Gross & S. Haroche, Physics reports 93, 301-396 (1982). [3] W. Feng, Y. Li & S-Y. Zhu, Phys. Rev. A 88, 033856 (2013). [less ▲]

Detailed reference viewed: 14 (1 ULg)