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See detailRécits de vie d’adolescents. Humeur dépressive et figures parentales
Poudat, Céline; Boulard, Aurore ULg

in 4ème Congrès Mondial de Linguistique Française (2014, July 22)

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See detailDetection of differential item functioning using the lasso approach
Magis, David ULg; Tuerlinckx, Francis; De Boeck, Paul

Conference (2014, July 22)

The purpose of this talk is to present a novel approach to detect differential item functioning (DIF) among dichotomously scored items. Unlike standard DIF methods that perform an item-by-item analysis ... [more ▼]

The purpose of this talk is to present a novel approach to detect differential item functioning (DIF) among dichotomously scored items. Unlike standard DIF methods that perform an item-by-item analysis, we consider a logistic regression model including item-group interaction (i.e. DIF) effects of all items simultaneously. The method is based on penalized maximum likelihood estimation of a model with a lasso penalty on all possible DIF parameters. Optimal penalty parameter selection is investigated through several known information criteria (such as AIC and BIC) as well as a newly developed weighted alternative. A simulation study was conducted to compare the global performance of the suggested “lasso DIF” method to the logistic regression and Mantel-Haenszel methods, and to evaluate the different optimal penalty parameter selection methods. It is concluded that for small samples the lasso DIF approach globally outperforms the logistic regression method, and also the Mantel-Haenszel method, especially in the presence of item impact, while it yields similar results with larger samples. [less ▲]

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See detailThe performance of mobile devices' inertial measurement unit for the detection of cattle's behaviors on pasture
Andriamandroso, Andriamasinoro ULg; Dumont, Benjamin ULg; Lebeau, Frédéric ULg et al

Conference (2014, July 21)

Over the past decade, the Precision Livestock Farming (PLF) concept has taken a considerable place in the development of accurate methods for a better management of farm animals, as Precision Agriculture ... [more ▼]

Over the past decade, the Precision Livestock Farming (PLF) concept has taken a considerable place in the development of accurate methods for a better management of farm animals, as Precision Agriculture has done for crop production. Mass consumption mobile devices have nowadays the possibility to record accurately user movements with their Inertial Measurement Unit (IMU). We used iPhone 4S to detect accurately cattle behaviors such as grazing and ruminating with the aim of performing a precision grazing management on the near future. Results showed accuracies ranging between 84% and 100% when detecting these two major behaviors by analyzing recorded raw signals in the time-domain. Ongoing research tries to link these behaviors to different pasture characteristics and performs a refined signal processing analysis for a better monitoring of some possible behavioral changes. [less ▲]

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See detailThe vegetative state/unresponsive wakefulness syndrome: a systematic review of prevalence studies
Van Erp, WS; Lavrijsen, JC; Van De Laar, FA et al

in European Journal of Neurology (2014)

One of the worst outcomes of acquired brain injury is the vegetative state, recently renamed ‘unresponsive wakefulness syndrome’ (VS/UWS). A patient in VS/UWS shows reflexive behaviour such as spontaneous ... [more ▼]

One of the worst outcomes of acquired brain injury is the vegetative state, recently renamed ‘unresponsive wakefulness syndrome’ (VS/UWS). A patient in VS/UWS shows reflexive behaviour such as spontaneous eye opening and breathing, but no signs of awareness of the self or the environment. We performed a systematic review of VS/UWS prevalence studies and assessed their reliability. Medline, Embase, the Cochrane Library, CINAHL and PsycINFO were searched in April 2013 for cross-sectional point or period prevalence studies explicitly stating the prevalence of VS/UWS due to acute causes within the general population. We additionally checked bibliographies and consulted experts in the field to obtain ‘grey data’ like government reports. Relevant publications underwent quality assessment and data-extraction. We retrieved 1032 papers out of which 14 met the inclusion criteria. Prevalence figures varied from 0.2 to 6.1 VS/UWS patients per 100 000 members of the population. However, the publications’ methodological quality differed substantially, in particular with regards to inclusion criteria and diagnosis verification. The reliability of VS/UWS prevalence figures is poor. Methodological flaws in available prevalence studies, the fact that 5/14 of the studies predate the identification of the minimally conscious state (MCS) as a distinct entity in 2002, and insufficient verification of included cases may lead to both overestimation and underestimation of the actual number of patients in VS/UWS. [less ▲]

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See detailLiver proteomic response to hypertriglyceridemia in human-apolipoprotein C-III transgenic mice at cellular and mitochondrial compartment levels
Ehx, Grégory ULg; Gerin, Stéphanie ULg; Mathy, Grégory et al

in Lipids in Health and Disease (2014), 13

Background: Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute ... [more ▼]

Background: Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute pancreatitis. The present study was undertaken to investigate the impact of hypertriglyceridemia on the mitochondrial, sub-mitochondrial and cellular proteomes in the hepatocytes of a hypertriglyceridemic transgenic mouse model overexpressing the human apolipoproteinC-III. Methods: Quantitative comparative proteomics (2D-DIGE) was carried out in both “low-expressor” (LE) and “high-expressor” (HE) mice, respectively exhibiting moderate and severe HTG, to characterize the effect of the TG plasma level on the proteomic response. Results: The mitoproteome analysis revealed the occurrence of a large-scale adaptation in transgenic mice consisting of a general down-regulation of matricial proteins and up-regulation of inner membrane proteins. Remarkably, the magnitude of these proteomic changes appears to strongly depend on the TG plasma level. Altogether, our different analyses indicate that, in HE mice, the capacity of several metabolic pathways is altered to promote the availability of acetyl-CoA, glycerol-3-phosphate, ATP and NADPH for de novo TG biosynthesis. The up-regulation of several cytosolic ROS detoxifying enzymes also tend to confirm that the cytoplasm of HTG mice is subjected to oxidative stress as previously stated. The up-regulation of cytosolic ferritin indicates that iron over-accumulation could take place in the cytosol of HE mice hepatocytes and contribute to (i) enhance oxidative stress and (ii) promote cellular proliferation. Conclusions: The present analyses demonstrate that important TG dose-responsive metabolic adaptations are set up in human apolipoproteinC-III-overexpressing mice. Our results indicate that these adaptations could support the higher TG production rates which have been previously reported in this HTG model, and also suggest that cytosolic oxidative stress may result from FFA over-accumulation, iron overload and enhanced activity of some ROS-producing catabolic enzymes. [less ▲]

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See detailSeed dispersal by western lowland gorillas: what about gut passage effect?
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Conference (2014, July 21)

Animal-mediated seed dispersal is an essential ecological process in the tropics. Among African primates, the critically endangered western lowland gorilla (WLG) seems to fulfill many characteristics of ... [more ▼]

Animal-mediated seed dispersal is an essential ecological process in the tropics. Among African primates, the critically endangered western lowland gorilla (WLG) seems to fulfill many characteristics of an effective seed disperser. WLG preferentially disperses species of various seed-size into open canopy habitats suitable for seedling growth. However, few studies have addressed the effects of the passage through the digestive tract on germination. Thus, the effectiveness of WLG in ecological processes governing forest dynamics and regeneration is still poorly known. Seed dispersal by WLG was studied in Central Gabon and Southeast Cameroon. Dispersed seed were identified from fresh fecal samples. Comparative germination trials based on 5 treatments (seeds from fresh fruits, seeds from fresh fruits surrounded by pulp, seeds from fresh fruits with fecal matrix, seeds from feces and seeds from feces with fecal matrix) were realized for 13 species. We recorded germination success for all species and germination delay for 6 species. Our results suggest a neutral gut passage effect for 54% and positive effect for 40% of tested species. Germination success enhancement was linked to another factor than pulp suppression. For two species, pulp suppression enhanced germination success, but not gut passage. The presence of pulp or fecal matrix surrounding the seed seemed to longer germination delay, while gut passage would not fasten germination. Globally, we conclude that WLG dispersed seeds are not damaged by gut passage. Consequently, WLG is thought to provide effective ecological services that could be essential to the maintenance and the recovery of forest ecosystems. [less ▲]

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See detailThe VORTEX project: first results and perspectives
Absil, Olivier ULg; Mawet, Dimitri; Delacroix, Christian ULg et al

in Marchetti, Enrico; Close, Laird; Véran, Jean-Pierre (Eds.) Adaptive Optics Systems IV (2014, July 21)

Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the ... [more ▼]

Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the diffraction limit of the telescope), a clear 360 degree discovery space, have demonstrated very high contrast capabilities, are easy to implement on high-contrast imaging instruments, and have already been extensively tested on the sky. Since 2005, we have been designing, developing and testing an implementation of the charge-2 vector vortex phase mask based on concentric sub-wavelength gratings, referred to as the Annular Groove Phase Mask (AGPM). Science-grade mid-infrared AGPMs were produced in 2012 for the first time, using plasma etching on synthetic diamond substrates. They have been validated on a coronagraphic test bench, showing broadband peak rejection up to 500:1 in the L band, which translates into a raw contrast of about 6e-5 at 2λ/D. Three of them have now been installed on world-leading diffraction-limited infrared cameras, namely VLT/NACO, VLT/VISIR and LBT/LMIRCam. During the science verification observations with our L-band AGPM on NACO, we observed the beta Pictoris system and obtained unprecedented sensitivity limits to planetary companions down to the diffraction limit (0.1"). More recently, we obtained new images of the HR 8799 system at L band during the AGPM first light on LMIRCam. After reviewing these first results obtained with mid-infrared AGPMs, we will discuss the short- and mid-term goals of the on-going VORTEX project, which aims to improve the performance of our vortex phase masks for future applications on second-generation high-contrast imager and on future extremely large telescopes (ELTs). In particular, we will briefly describe our current efforts to improve the manufacturing of mid-infrared AGPMs, to push their operation to shorter wavelengths, and to provide deeper starlight extinction by creating new designs for higher topological charge vortices. Within the VORTEX project, we also plan to develop new image processing techniques tailored to coronagraphic images, and to study some pre- and post-coronagraphic concepts adapted to the vortex coronagraph in order to reduce scattered starlight in the final images. [less ▲]

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See detailWhat, how, and why to mix research methods in the study of career patterns?
Dodeigne, Jérémy ULg

Conference (2014, July 20)

Political careers have become more diversified in multi-level systems over the last decades. In ‘classic’ federations (e.g. the US, Canada, and Germany), regional offices have become attractive positions ... [more ▼]

Political careers have become more diversified in multi-level systems over the last decades. In ‘classic’ federations (e.g. the US, Canada, and Germany), regional offices have become attractive positions with the process of professionalization. In newly regional political systems (e.g. Belgium, Spain, and the UK), the regional level has been quickly perceived by ambitious candidates as a professionalized political arena. Overall, regional positions in multi-level contexts are no longer conceived as amateur positions or mere stepping stones towards the national level. Despite the growing literature on the topic, several methodological questions remain nonetheless opened. This paper discusses the benefits and limitations of a mix-methods research design relevant for the study of elites’ career patterns. Specifically, the paper presents how and why mixing two quantitative and qualitative methods: survival analysis and life story interviews (for the purpose of illustration, the paper relies on empirical data: 1.831 careers and 84 life stories). Firstly, I introduce separately the added-value of each research methods (I especially discuss the benefits of these approach to collect and analyze longitudinal data in a context of multi-level system). Secondly, I demonstrate how these two methods permit to better understand elites’ career patterns in the context of multi-level systems. [less ▲]

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See detailShort Prime Quadratizations of Cubic Negative Monomials
Crama, Yves ULg; Rodriguez Heck, Elisabeth ULg

E-print/Working paper (2014)

Pseudo-Boolean functions naturally model problems in a number of different areas such as computer science, statistics, economics, operations research or computer vision, among others. Pseudo-Boolean ... [more ▼]

Pseudo-Boolean functions naturally model problems in a number of different areas such as computer science, statistics, economics, operations research or computer vision, among others. Pseudo-Boolean optimization (PBO) is NP-hard, even for quadratic polynomial objective functions. However, much progress has been done in finding exact and heuristic algorithms for the quadratic case. Quadratizations are techniques aimed at reducing a general PBO problem to a quadratic polynomial one. Quadratizing single monomials is particularly interesting because it allows quadratizing any pseudo-Boolean function by termwise quadratization. A characterization of short quadratizations for negative monomials has been provided. In this report we present a proof of this characterization for the case of cubic monomials, which requires a different analysis than the case of higher degree. [less ▲]

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See detailA Bi-Objective Location-Allocation Model for Intermodal Terminals
Mostert, Martine ULg; Caris, An; Limbourg, Sabine ULg

Conference (2014, July 18)

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See detailDetermination of the ruminant origin of bone particles using fluorescence in situ hybridization (FISH).
Lecrenier, Marie-Caroline ULg; Ledoux, Quentin; Berben, Gilbert et al

in Scientific reports (2014), 4

Molecular biology techniques such as PCR constitute powerful tools for the determination of the taxonomic origin of bones. DNA degradation and contamination by exogenous DNA, however, jeopardise bone ... [more ▼]

Molecular biology techniques such as PCR constitute powerful tools for the determination of the taxonomic origin of bones. DNA degradation and contamination by exogenous DNA, however, jeopardise bone identification. Despite the vast array of techniques used to decontaminate bone fragments, the isolation and determination of bone DNA content are still problematic. Within the framework of the eradication of transmissible spongiform encephalopathies (including BSE, commonly known as "mad cow disease"), a fluorescence in situ hybridization (FISH) protocol was developed. Results from the described study showed that this method can be applied directly to bones without a demineralisation step and that it allows the identification of bovine and ruminant bones even after severe processing. The results also showed that the method is independent of exogenous contamination and that it is therefore entirely appropriate for this application. [less ▲]

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See detailInventory-routing problem with pickups and deliveries of RTI in closed-loop supply chain
Iassinovskaia, Galina; Limbourg, Sabine ULg; Riane, Fouad

Conference (2014, July 17)

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their Returnable Transport Items (RTIs) among different partners of a ... [more ▼]

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their Returnable Transport Items (RTIs) among different partners of a closed-loop supply chain. This research deals with an inventory-routing problem with pickups and deliveries of RTIs. A mixed-integer linear program is developed and tested on small instances. To handle realistic large size problems, a clustering algorithm is coupled with a simulation model. This hybrid heuristic allows assessing the benefits of information and RTIs sharing among partners. [less ▲]

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See detailResorcinol-Formaldehyde Carbon Xerogels as Lithium-Ion Battery Anodes: Synthesis, Grinding, Coating on current collector and Electrochemical characterization
Piedboeuf, Marie-Laure ULg; Léonard, Alexandre ULg; Pirard, Jean-Paul ULg et al

Poster (2014, July 17)

Rechargeable lithium-ion batteries show great advantages over traditional batteries and are extensively used for consumer electronic devices due to their high energy density and long cycle life. However ... [more ▼]

Rechargeable lithium-ion batteries show great advantages over traditional batteries and are extensively used for consumer electronic devices due to their high energy density and long cycle life. However, the improvement of performance of current lithium-ion batteries requires the optimization of the materials used (electrolyte and electrodes). Therefore, tremendous efforts have been dedicated to exploring new materials with high capacity, excellent cycling performance, low cost and high safety features [1-4]. As an example, carbon xerogels are promising candidates in the development of new high performance C-based anode materials for Li-ion batteries, since such carbonaceous materials show very small changes of volume during the charge/discharge process, providing an improved cycle life. Nevertheless, hard carbons also exhibit quite high irreversible capacity losses due to their intrinsic high microporosity and, compared to graphite, a poor rate performance related to slow diffusion of Li in the internal structure [5-6]. To reduce these disadvantages, the structural and textural characteristics need to be carefully controlled. Also, due to the different morphology of these materials compared to graphite, the deposition of carbon xerogels on current collectors needs to be studied in detail. In this work, porous carbon xerogels were synthetized from Resorcinol-Formaldehyde mixtures by adjusting the pH of the solution in order to obtain different mesopore sizes. Monoliths of carbon xerogels were obtained after drying of the polymer gel and pyrolysis [7]. Mercury intrusion porosimetry and nitrogen adsorption techniques (BET) was used to characterize the pore texture of the carbon xerogels. These monoliths were ground to particles around 10 µm for all the samples. The resulting powders were then mixed with a binder and a solvent to form slurries and then cast on copper foil using a bar coater. After evaporation of the solvent, the resulting coatings were analyzed using scanning electron microscopy (SEM) for the morphology and their thickness was monitored by profilometry. The resulting electrodes were subjected to electrochemical characterization. Since the particle sizes and the method of coating was the same for all the samples, it was possible to evaluate selectively the influence of the textural and structural parameters of the different carbon materials on their performances. Electrochemical characterizations were performed using charge-discharge galvanostatic curves and cyclic voltammetry in Li/C half cells between 0.005 and 1.5 V vs. Li+/Li. References 1) Goodenough J.B., Kim Y. J. Power Sources 2011; 196(16): 6688-6694. 2) Bruce P.G. Solid State Ionics 2008; 179: 752-760. 3) Armand M., Tarascon J.-M., Nature 2008; 451: 652-657. 4) Scrosati B., Garche J., J. Power Sources 2010 ; 195 : 2419-2430. 5) Yuan X., Chao Y.-J., Ma Z.-F., Deng X., Electrochemistry Communications 2007 ; 9 : 2591-2595. 6) Zanto E.J., Ritter J.A., Popov B.N., Proceedings - Electrochemical Society 1999; 98-16: 71-8. 7) Job N., Théry A., Pirard R., Marien J., Kocon L., Rouzaud J., Béguin F., Pirard J. Carbon 2005; 43: 2481-2494. [less ▲]

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See detailThe Man in the Moon: A Survival of Germanic Mythology?
Dor, Juliette ULg

Conference (2014, July 17)

Men and women imagined the presence of the Man in the Moon in order to account for the spots in the full moon. There are a number of references to him (and sometimes to a woman) in English folklore and ... [more ▼]

Men and women imagined the presence of the Man in the Moon in order to account for the spots in the full moon. There are a number of references to him (and sometimes to a woman) in English folklore and literature (seal of Walter de Grendon, nursery rhymes, Neckam, ME poem, Chaucer, Shakespeare…). He was thought to have been exiled there and carries a thorn bush on his back because he once stole thorns from hedges (or violated some religious commandment). There is a variant of the legend in Snorri: the moon-god Máni (ON ‘moon’) once took two children from earth when they were coming from a spring carrying a bushel and a pole on their shoulders; as can be seen from the earth, the boy and the girl are still in the sky and follow the moon. I want to argue that this familiar Scandinavian and English figure – but also present in France and Wallonia -probably derives from an ancient Germanic myth that developed slightly differently among the Northern and Western countries, and that the two traditions eventually merged due to the contacts between the Scandinavians and the English. [less ▲]

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

Conference (2014, July 17)

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

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

Detailed reference viewed: 9 (0 ULg)