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See detailCombining PET images and neuropsychological test data for automatic diagnosis of Alzheimer’s disease
Segovia-Román, Fermín ULg; Bastin, Christine ULg; Salmon, Eric ULg et al

in PLoS ONE (2014), 9(2),

In recent years, several approaches to develop computer aided diagnosis (CAD) systems for dementia have been proposed. Some of these systems analyze neurological brain images by means of machine learning ... [more ▼]

In recent years, several approaches to develop computer aided diagnosis (CAD) systems for dementia have been proposed. Some of these systems analyze neurological brain images by means of machine learning algorithms in order to find the patterns that characterize the disorder, and a few combine several imaging modalities to improve the diagnostic accuracy. However, they usually do not use neuropsychological testing data in that analysis. The purpose of this work is to measure the advantages of using not only neuroimages as data source in CAD systems for dementia but also neuropsychological scores. To this aim, we compared the accuracy rates achieved by systems that use neuropsychological scores beside the imaging data in the classification step and systems that use only one of these data sources. In order to address the small sample size problem and facilitate the data combination, a dimensionality reduction step (implemented using three different algorithms) was also applied on the imaging data. After each image is summarized in a reduced set of image features, the data sources were combined and classified using three different data combination approaches and a Support Vector Machine classifier. That way, by testing different dimensionality reduction methods and several data combination approaches, we aim not only highlighting the advantages of using neuropsychological scores in the classification, but also implementing the most accurate computer system for early dementia detention. The accuracy of the CAD systems were estimated using a database with records from 46 subjects, diagnosed with MCI or AD. A peak accuracy rate of 89% was obtained. In all cases the accuracy achieved using both, neuropsychological scores and imaging data, was substantially higher than the one obtained using only the imaging data. [less ▲]

Detailed reference viewed: 103 (8 ULg)
See detailQuelle plus-value retirer du système de prévention et protection au travail ?
Mairiaux, Philippe ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 19 (4 ULg)
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See detailDevelopment of educational info capsules proposing instructional strategies aiming to deal with overweight and obese students
Cloes, Marc ULg; LEBRETHON, Marie-Christine ULg; Feron, Isaline

Conference (2014, February 13)

Irwin et al. (2003) pointed out the principles that quality PE teachers should incorporate into their pedagogical practice in order to take into account the increasing number of overweight and obese ... [more ▼]

Irwin et al. (2003) pointed out the principles that quality PE teachers should incorporate into their pedagogical practice in order to take into account the increasing number of overweight and obese students in their classes. Fighting against obesity is so complex that no simple solution can be proposed. It means that the development of specific tools providing PE teachers with new instructional strategies inspired from public health is needed (Prusak et al., 2011). Inclusion of overweight students into PE can be linked with a social ecological model (Li & Rukavina, 2012). Even if PE teachers are able to develop and implement specific instructional strategies, it seems that they need support from health experts (Cloes et al., 2013). Internet, continuing professional development activities, and educational info capsules were identified as the preferred supports to be used by the practitioners (Cloes et al., 2014). The aims of this study were to produce and validate three pedagogical capsules focusing on specific concerns of PE teachers as well as to analyze the procedure of validation. Using an extensive analysis of the literature, the researchers first identified theoretical and practical resources to be mobilized in the understanding and development of solutions for the selected problems: (1) Students’ lack of awareness about the risks of overweight and obesity; (2) Constraints associated with the motor/physical disabling; (3) Parents’ lack of awareness about PA impact on health. The capsules were then submitted to 11 experts (health specialists, health educators, psychologists, PE teachers) who had to analyze the documents. They acknowledged the content and form of the capsules. Minor changes were requested in order to finalize them. The proposed evaluation sheet was also validated but face-to-face assessment was recommended. Dissemination of the existing capsules as well as development of additional ones should be the next steps of this project. [less ▲]

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See detailLes hiéroglyphes à l'heure de l'informatique
Winand, Jean ULg

Scientific conference (2014, February 13)

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See detailL'architecture Art nouveau à Liège (1895-1914)
Charlier, Sébastien ULg

Conference (2014, February 13)

Detailed reference viewed: 38 (1 ULg)
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See detailImportance des récentes variations pluviométriques à Djibouti et besoins de quantification de leurs impacts
Mahamoud, Ayan; Nour Ayeh, Moustapha; Saad, Osman et al

Poster (2014, February 12)

Ces dernières décennies, l’Afrique de l’Est souffre d’une longue et lente détérioration pluviométrique. De 2007 à 2011, la ville de Djibouti a enregistré un déficit de 73% des précipitations moyennes ... [more ▼]

Ces dernières décennies, l’Afrique de l’Est souffre d’une longue et lente détérioration pluviométrique. De 2007 à 2011, la ville de Djibouti a enregistré un déficit de 73% des précipitations moyennes annuelles par rapport à la moyenne de 30 ans (1981-2010). Pour caractériser la sécheresse actuelle, nous analysons une série pluviométrique reconstruite pour Djibouti-Ville de 1901 à 2013, les données de terrain permettant d’illustrer les impacts de ces variations pluviométriques. Les précipitations enregistrées à Djibouti ne présentent aucune tendance sur le long terme (1901-2013). Par contre, ces dernières années montrent une très grande variabilité: le suivi de la moyenne pluviométrique sur 10 ans est à son maximum en 1998 (215 mm) et à son minimum en 2013 (79 mm). Depuis 2007, la pluie totale annuelle ne dépasse plus les 100 mm. C’est cette succession d’années déficitaires qui est problématique. Cette sécheresse sans précédent va mettre de nombreuses familles des zones rurales (de Djibouti, d’Ethiopie et de Somalie) sur la route. Cette migration a pour point de chute la ville de Djibouti où des quartiers neufs se créent, comme Buldhuqo. Totalement inexistant en 2004, il explose après 2009. Les derniers arrivants s’installent dans le fond de l’oued, là même où la zone était inondée en 2004 et 2009 suite à des pluies courtes mais intenses. La prochaine pluie extrême, l’exposition de ces populations précaires aux risques hydrologiques sera maximale. [less ▲]

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See detailPRESSE: Notre regard aggrave le vieillissement ...
Adam, Stéphane ULg

Diverse speeche and writing (2014)

Detailed reference viewed: 6 (1 ULg)
See detailLe théâtre-action en Belgique : engagement social et/ou critique politique ?
Brahy, Rachel ULg; Adam, Daniel; François, Yvon et al

Conference given outside the academic context (2014)

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See detailConstraints experienced by physical education teachers with overweight and obese students
Cloes, Marc ULg; Feron, Isaline; LEBRETHON, Marie-Christine ULg

Conference (2014, February 10)

Despite ‘antifat’ attitude of some PE teachers (Greenleaf & Weiller, 2005) and the PE public relations problem in regard to how obese students are treated (Irwin et al., 2003), it seems evident that this ... [more ▼]

Despite ‘antifat’ attitude of some PE teachers (Greenleaf & Weiller, 2005) and the PE public relations problem in regard to how obese students are treated (Irwin et al., 2003), it seems evident that this school subject represents a key element in the involvement of the education sector in the fight against the worldwide escalating global epidemic of obesity (Tappe & Burgeson, 2004). In fact, PE teachers consider that they lack of specific knowledge to implement instructional strategies dealing with overweight and obese students (Cloes & Ziant, 2009). Some authors proposed models to illustrate constraints that PE teachers encounter in their classes with obese students and their potential solutions (Cloes et al., 2013; Rukavina et al., 2010). On the other hand, data are missing when identifying those that are considered as their main concerns and the ways that they would prefer to receive some support regarding this specific topic. This study is focused on these two aspects. Five hundred thirteen PE teachers fulfilled an online questionnaire (Lickert scales) in which they had to determine (1) the perceived importance of 20 problems proposed by PE teachers and validated by 8 experts; (2) their relative interest toward the reception of support aiming to deal with those problems; (3) their preference for receiving information about the potential instructional strategies. Based on the answers, the top 3 problems are: (1) Students’ lack of awareness about the risks of overweight and obesity; (2) Constraints associated with the motor/physical disabling; (3) Parents’ lack of awareness about physical activity impact on health. Internet (3.49±.6/4), continuing professional development activities (3.29±.8/4), and educational info capsules (3.07±.8/4) were identified as the main resources that PE teachers would use preferentially. This study provides useful information for PE teachers’ educators who should develop now material to be shared with the practitioners. [less ▲]

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See detailSpace-variant optical phase retarders in liquid crystal polymers and their applications
Piron, Pierre ULg

Doctoral thesis (2014)

During the last decade, extensive investigations were performed to achieve optical phase retarders with a space-variant orientation of their fast axis. These retarders present unique behaviors and they ... [more ▼]

During the last decade, extensive investigations were performed to achieve optical phase retarders with a space-variant orientation of their fast axis. These retarders present unique behaviors and they can be used for several applications such as polarization analysis, beam splitting, phase mask coronagraphy, optical tweezers … The present thesis is dedicated to the development of space-variant retarders made out of liquid crystal polymers recorded by polarization holography. The liquid crystals define the fast axis orientation of the retarder. Polarization holography is based on the superimposition of differently polarized beams to achieve the electric field required to properly align the liquid crystals without mechanical action. In the present work, we start with an introduction about the space-variant retarders, their characteristics and current recording methods, which usually require mechanical action. In the second chapter, polarization holography and several simple examples are presented as well as the liquid crystal polymers, their generic recording process and the first prototypes. In chapter three, the first application that we developed is exposed. It consists in a polarization analysis method based on a retarder characterized by a variation in one dimension of its fast axis orientation. The principle of the method, numerical simulations and the first results are exposed. Chapter four cares about the second application based on a separator of polarization state. The mathematical model and its application to shearography are exposed. In chapter five, another kind of retarders is introduced. These retarders are characterized by a rotation of their fast axis along the center of the retarder. Their properties, the recording systems and the first prototypes are detailed and analyzed. In the last chapter, the application of our retarder to coronagraphy is presented and their performances are computed for different configurations based on experimental constrains. Finally, we conclude with the improvements of our applications and future uses of these retarders. [less ▲]

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See detailNew mass spectrometry based methodology to sequence a whole snake venom
Echterbille, Julien ULg; Boulanger, Madeleine; Degueldre, Michel ULg et al

Poster (2014, February 10)

Animal venoms are complex chemical cocktails, comprising wide ranges of biologically active reticulated peptides that target with high selectivity and efficacy varieties of membrane receptors. Assuming ... [more ▼]

Animal venoms are complex chemical cocktails, comprising wide ranges of biologically active reticulated peptides that target with high selectivity and efficacy varieties of membrane receptors. Assuming the fact that each of the 170,000 venomous species reported can produce more than 250 bioactive toxins, at least 40,000,000 bioactive peptides and proteins may be discovered. Among the four described species of mambas, Eastern Jameson’s mamba (Dendroaspis jamesonii kaimosae) venom is the less characterized since only 9 peptides are referenced in database. This work aims at developing a new strategy devoted to the deep analysis of animal venoms. Our approach consists in a first separation of the venom using cation exchange chromatography. Each primary fraction is then purified a second time by classical RP-HPLC. A total of 328 fractions, containing amongst 1 and 4 toxins, are finally collected. MALDI-MS analysis of each fraction is done in order (1) to obtain information about masses and (2) to obtain sequences of toxins thanks to MALDI-In Source Decay (ISD) dissociation coupled with on MALDI target plate reduction of the peptides. ISD has already been demonstrated efficient for toxin sequencing, and especially when using 1,5-DAN as reducing matrix. ISD yields to sequences that cover more than 50% of peptide sequences by series of singly charged c-type ions. Thanks to this methodology, we were able to obtain 85% of satisfactory results i.e. spectra giving quite long tags of amino acids (up to 20 residues). As a way to validate our method, a tag coming from ISD spectrum interpretation has found a match in database for an Eastern Jameson’s mamba toxin. The global sequence has then been obtained by extrapolation on the ISD spectrum. Since ISD spectra are simpler than classical MS/MS spectra, automation of spectra interpretation, difficult with other fragmentation techniques (CID, ETD…), is implementable. In the near future, sequences obtained with this approach will be used to direct tests of biological activity through sequence homologies with already known ligands for different kinds of membrane receptors. [less ▲]

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See detailMolecular dynamic simulation of the cyclic lipodepsipeptide Pseudodesmin A self-assembly
Crowet, Jean-Marc ULg; Sinnaeve, Davy; Fehér, Krisztina et al

Conference (2014, February 10)

Pseudodesmine A is a cyclic lipodepsipeptide of nine residues which presents a moderate antibacterial activity and whose structure has been resolved by X-ray and NMR1,2. In acetonitrile, Pseudodesmine A ... [more ▼]

Pseudodesmine A is a cyclic lipodepsipeptide of nine residues which presents a moderate antibacterial activity and whose structure has been resolved by X-ray and NMR1,2. In acetonitrile, Pseudodesmine A is monomeric while in chloroform it has the same structure but assemble in a supramolecular complex. This structure could associate with membranes and be responsible of the biological activity of this peptide. Comparison of the NMR data between the two solvents has given indications on the intermolecular contacts that arise in chloroform and a model for the self association was proposed2,3. To study in more details this assembly, molecular dynamics have been carried on. In acetonitrile, the peptide show transient interactions while in chlorofom interactions between monomers was always observed. As stated in Sinnaeve et al. in 2009, these interactions arise mainly between the backbone protons of the LEU1 and the GLN2, the GLN2 sidechain and the loop located on the opposite end of the monomer structure. From 10 simulations of dimerization, hydrogen bonds were followed and specific interaction patterns were identified regarding the hydrogen bonds formed. The peptide interactions are mainly described by 13 interaction patterns; 8 with the peptides in a linear configuration, 1 perpendicular and 4 with peptides side by side. The patterns are characterized by 2 to 4 hydrogen bonds. From the linear dimer, it is possible to reconstruct filaments and, by combining a linear and a lateral dimer, it is possible to build fibrils with multi filaments, as expected in the NMR derived model. Besides, the perpendicular dimer can gives peptide rings that can also explain the potential ability of this peptide to form ion pores in membranes. 1. Sinnaeve, D., Michaux, C., Van hemel, J., Vandenkerckhove, J., Peys, E., Borremans, F. a. M., Sas, B., Wouters, J. and Martins, J. C. Tetrahedron 2009, 65, 4173–4181. 2. Sinnaeve, D., Hendrickx, P. M. S., Van Hemel, J., Peys, E., Kieffer, B. and Martins, J. C. Chemistry (Weinheim an der Bergstrasse, Germany) 2009, 15, 12653–62. 3. Sinnaeve, D., Delsuc, M.-A., Martins, J. C. and Kieffer, B. Chemical Science 2012, 3, 1284. [less ▲]

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See detailAllo- and autoinhibition in barley and great brome: a laboratory study
Bouhaouel, Imen ULg; Gfeller, Aurélie; Fauconnier, Marie-Laure ULg et al

Conference (2014, February 08)

Detailed reference viewed: 31 (12 ULg)
See detailAccumulation primitive et dictature du prolétariat. Une lecture conjoncturelle du dernier Althusser
Mancuso, Eva ULg; Bruschi, Fabio

Scientific conference (2014, February 08)

Detailed reference viewed: 13 (1 ULg)
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See detailINFLUENCE OF STEAM EXPLOSION ON THECRYSTALLINITY OF CELLULOSE FIBER
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2014, February 07)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity. [less ▲]

Detailed reference viewed: 33 (3 ULg)