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See detailEstimated Subglottic Pressure Evaluation, Evolution in 152 Dysphonic Patients
Morsomme, Dominique ULg; Finck, Camille ULg; Larrouy, Pauline ULg

Conference (2015, April 08)

Background: Estimated subglottic pressure (ESGP) is part of the aerodynamic measurements included in the vocal profile. It is an indication of vocal effort. Speyer reports an improvement of the ESGP score ... [more ▼]

Background: Estimated subglottic pressure (ESGP) is part of the aerodynamic measurements included in the vocal profile. It is an indication of vocal effort. Speyer reports an improvement of the ESGP score after voice treatment. Nevertheless, few studies used ESGP to evaluate voice efficiency treatment. Objectives: The purpose is to examine the ESGP twice, at the first (T1) and the last consultation (T2) . We observe the ESGP values according to voice pathology. We also examine the relationships between ESGP, SPL(Sound pressure level) and DSI (Discorder severity index) . Method: The study includes 130 patients (M:31/W:99), which suffer from 4 different pathologies as immobility (N: 54), oedema (N:23), nodules (N:24) and polyp (N:29). Each patient’s file consists of VLS, acoustic, aerodynamic and perceptual measures. The ESGP was collected through the Phonatory Aerodynamic System Model 6600 (KayPentax). Patients produced 3 sequences of / ipipi / at low (IL), conversational (IC) and high (IH) intensity. Patients were grouped according to the ENT’s diagnosis. We compare our values to those of Zraick et al (2012) which studied ESGP on a healthy group. Results: At T2, for the all patients, at minimum and conversational intensity the ESGP scores decrease singificantly, even if those scores were higher than for the healthy group. We observe a negative correlation between ESGP and SPL at low and conversational intensity. At T1, the higher is the ESGP score, the lower is the SPL score. At T2, the higher is the ESGP score, the higher is the SPL score. At T1, a negative correlation is observed between ESGP and DSI for 2 groups of patients (immobility and polyp) only at minimum intensity. The higher is the ESGP, the lower is SPL. At T2, only for the group immobility, the negative correlation persists. Conclusion: This study highlights the importance of considering the ESGP as a parameter of efficiency. High ESGP is mainly connected with patients who suffer from pathology. The patient who suffer from immobility seems to present a specific profile which could help the clinician to better understand their vocal behavior. Recommendation: This study highlights the pertinence of considering the ESGP as a parameter of vocal treatment efficiency. [less ▲]

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See detailAging Mechanisms in Amorphous GeTe
Raty, Jean-Yves ULg; Zhang, Wei; Luckas, Jennifer et al

Conference (2015, April 08)

We investigate the structure of amorphous GeTe using Density Functional Theory based Molecular Dynamics, using either the standard Generalized Gradient Approximation, or the more elaborate Van der Waals ... [more ▼]

We investigate the structure of amorphous GeTe using Density Functional Theory based Molecular Dynamics, using either the standard Generalized Gradient Approximation, or the more elaborate Van der Waals approximation. New insight is provided on the stability of homopolar GeGe bonds and tetrahedral Ge bonding, in relation with the resistance drift phenomenon, that is investigated experimentally using photothermal deflection spectroscopy experiments. Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have been proposed, but we focus here on the structural relaxation of amorphous GeTe, chosen because it is the simplest system that is representative of the wider class of GST alloys, lying along the GeTe-Sb2Te3 composition line of the GeSbTe phase diagram. Since the structural relaxations concerned with the drift take place on long time scales, the task of understanding them to limit their consequences is not a simple one. We successfully achieved this goal by developing new approaches to overcome a series of hurdles. A first problem is that directly generating an amorphous structure by quenching a liquid using Density Functional Theory (DFT) based Molecular Dynamics leads to one sample with a small number of atom (typically a few hundreds), and, hence of small number of atomic environments. Here we sample a large number of local atomic environments, corresponding to different bonding schemes, by chemically substituting different alloys, selected to favor different local atomic structures. This enables spanning a larger fraction of the configuration space relevant to aging. A second aspect is that GST alloys are known to display complex bonding mechanisms, for which the simple chemist’s “octet-rule” does not apply, leading a long series of controversies, concerning in particular the local structure around Ge atoms. We overcome this problem by using state of the art non local DFT-MD, including the so-called van der Waals corrections. This leads to more clearly defined environments that are thoroughly analyzed. We can then identify their fingerprints in the available structural experimental data and assess the stability of these local environments to obtain information of the driving forces leading to the structural relaxation. The calculated electronic properties nicely match the most recent photothermal deflection spectroscopy experiments that are presented here. Our results support a model of the amorphous phase and its time evolution that involves an evolution of the local (chemical) order towards that of the crystal (by getting rid of homopolar bonds), and an evolution of its electronic properties that drift away from those of the crystal, driven by an increase of the Peierls-like distortion of the local environments in the amorphous, as compared to the crystal. [less ▲]

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See detailGCxGC-TOFMS and supervised multivariate approaches to study human cadaveric decomposition olfactive signatures
Stefanuto, Pierre-Hugues ULg; Perrault, Katelynn A.; Stadler, Sonja et al

in Analytical Bioanalytical Chemistry (2015), 407(16), 4767-4778

In forensic thanato-chemistry, the understanding of the process of soft tissue decomposition is still limited. A better understanding of the decomposition process and the characterization of the ... [more ▼]

In forensic thanato-chemistry, the understanding of the process of soft tissue decomposition is still limited. A better understanding of the decomposition process and the characterization of the associated volatile organic compounds (VOC) can help to improve the training of victim recovery (VR) canines, which are used to search for trapped victims in natural disasters or to locate corpses during criminal investigations. The complexity of matrices and the dynamic nature of this process require the use of comprehensive analytical methods for investigation. Moreover, the variability of the environment and between individuals creates additional difficulties in terms of normalization. The resolution of the complex mixture of VOCs emitted by a decaying corpse can be improved using comprehensive two-dimensional gas chromatography (GC× GC), compared to classical singledimensional gas chromatography (1DGC). This study combines the analytical advantages of GC×GC coupled to timeof- flight mass spectrometry (TOFMS) with the data handling robustness of supervised multivariate statistics to investigate the VOC profile of human remains during early stages of decomposition. Various supervised multivariate approaches are compared to interpret the large data set. Moreover, early decomposition stages of pig carcasses (typically used as human surrogates in field studies) are also monitored to obtain a direct comparison of the two VOC profiles and estimate the robustness of this human decomposition analog model. In this research, we demonstrate that pig and human decomposition processes can be described by the same trends for the major compounds produced during the early stages of soft tissue decomposition. [less ▲]

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See detailState of the art on drivers of deforestation in the Congo basin tropical forest
Gillet, Pauline ULg; Vermeulen, Cédric ULg; Dessard, Hélène et al

Conference (2015, April 07)

The Congo basin forest experiment a low pressure on biodiversity in comparison to other rainforests around the world. But according to the predictions, climate change and direct human drivers could have ... [more ▼]

The Congo basin forest experiment a low pressure on biodiversity in comparison to other rainforests around the world. But according to the predictions, climate change and direct human drivers could have an important effect on the deforestation rate. In that context, CoForTips project want to foster a better management of the Congo Basin forests through a better understanding of the dynamics, regime shifts and tipping points of biodiversity and a better definition of the conditions of resilience of social and ecological systems. In order to assess the current knowledge about drivers of deforestation in the world tropical forests, we analyzed the existent literature to list the direct and indirect drivers of deforestation in the forested tropical zones and to focus on deforestation in the Congo Basin forest and specifically in Cameroon and Gabon. We listed direct drivers of deforestation like expansion of agriculture which can be either family farming or agribusiness; timber extraction for softwood industry and fuel wood; development of infrastructure leading to the opening up of forested land and populations, and mining industries. The underlying causes found in the literature concern economic factors like gross domestic product, national income based on environmental resources exploitation and consumer demand expressing on local and global markets. Technological factors that allow much larger removal. Cultural issues like representation of the forest in the collective imagination as an important source of economic income. Institutional factors like policy measures advocating pro-deforestation measures and demographic causes taking into account for local population rise due to a high fertility rate and linked to population migration. Those direct and underlying causes of deforestation where then detailed for Cameroon and Gabon. [less ▲]

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See detailStone tool hafting and use in the European Upper Palaeolithic: first results from Hohle Fels
Taipale, Noora ULg; Rots, Veerle ULg

Poster (2015, April 07)

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, whereas extensive studies that would utilise the full potential of functional ... [more ▼]

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, whereas extensive studies that would utilise the full potential of functional analysis have been few. In this poster, I will present the outline and first results of an ongoing PhD project dedicated to the variability in stone tool use and hafting in the Upper Palaeolithic of Central and Western Europe. Recent methodological developments have made possible the distinction between hafted and hand-held tools and the identification of different hafting modes in archaeological assemblages. The aim of my research is to understand the main developments and regional patterns in tool hafting and use in the Gravettian and Magdalenian, and evaluate their impact on lithic assemblage variability. The cave site Hohle Fels serves here as a case study, and the first results of the analysis of the site’s Gravettian material will be used to illustrate the potential of this kind of approach in the study of past human behaviour, cognition and culture. [less ▲]

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See detailEnvironmental constraints drive the partitioning of the soundscape in fishes
Ruppé, Laetitia; Clément, Gaël; Herrel, Anthony et al

in Proceedings of the National Academy of Sciences of the United States of America (2015)

The underwater environment is more and more being depicted as particularly noisy, and the inventory of calling fishes is continuously increasing. However, it currently remains unknown how species share ... [more ▼]

The underwater environment is more and more being depicted as particularly noisy, and the inventory of calling fishes is continuously increasing. However, it currently remains unknown how species share the soundscape and are able to communicate without misinterpreting the messages. Different mechanisms of interference avoidance have been documented in birds, mammals, and frogs, but little is known about interference avoidance in fishes. How fish thus partition the soundscape underwater remains unknown, as acoustic communication and its organization have never been studied at the level of fish communities. In this study, passive acoustic recordings were used to inventory sounds produced in a fish community (120 m depth) in an attempt to understand how different species partition the acoustic environment. We uncovered an important diversity of fish sounds, and 16 of the 37 different sounds recorded were sufficiently abundant to use in a quantitative analysis. We show that sonic activity allows a clear distinction between a diurnal and a nocturnal group of fishes. Moreover, frequencies of signals made during the day overlap, whereas there is a clear distinction between the different representatives of the nocturnal callers because of a lack of overlap in sound frequency. This first demonstration, to our knowledge, of interference avoidance in a fish community can be understood by the way sounds are used. In diurnal species, sounds are mostly used to support visual display, whereas nocturnal species are generally deprived of visual cues, resulting in acoustic constraints being more important. [less ▲]

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See detailRetrieval of ethane from ground-based FTIR solar spectra using improved spectroscopy: recent burden increase above Jungfraujoch
Franco, Bruno ULg; Bader, Whitney ULg; Toon, G. C. et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2015), 160(C), 36-49

An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station ... [more ▼]

An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5° N, 8.0° E, 3580m a.s.l.). The improved spectroscopic parameters include C2H6 pseudo-lines in the 2720-3100 cm-1 range and updated line parameters for methyl chloride and ozone. These improved spectroscopic parameters allow for substantial reduction of the fitting residuals as well as enhanced information content. They also contribute to limiting oscillations responsible for ungeophysical negative mixing ratio profiles. This strategy has been successfully applied to the Jungfraujoch solar spectra available from 1994 onwards. The resulting time series is compared with C2H6 total columns simulated by the state-of-the-art chemical transport model GEOS-Chem. Despite very consistent seasonal cycles between both data sets, a negative systematic bias relative to the FTIR observations suggests that C2H6 emissions are underestimated in the current inventories implemented in GEOS-Chem. Finally, C2H6 trends are derived from the FTIR time series, revealing a statistically-significant sharp increase of the C2H6 burden in the remote atmosphere above Jungfraujoch since 2009. Evaluating cause of this change in the C2H6 burden, which may be related to the recent massive growth of shale gas exploitation in North America, is of primary importance for atmospheric composition and air quality in the Northern Hemisphere. [less ▲]

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See detailScrivere il compromesso intorno al 1965
Curreri, Luciano ULg

Article for general public (2015)

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See detailPerspective: Tyrosine Phosphatases As Novel Targets For Antiplatelet Therapy
Tautz, Lutz; Senis, Yotis; Oury, Cécile ULg et al

in Bioorganic & Medicinal Chemistry (2015), Epub ahead of print

Arterial thrombosis is the primary cause of most cases of myocardial infarction and stroke, the leading causes of death in the developed world. Platelets, highly specialized cells of the circulatory ... [more ▼]

Arterial thrombosis is the primary cause of most cases of myocardial infarction and stroke, the leading causes of death in the developed world. Platelets, highly specialized cells of the circulatory system, are key contributors to thrombotic events. Antiplatelet drugs, which prevent platelets from aggregating, have been very effective in reducing the mortality and morbidity of these conditions. However, approved antiplatelet therapies have adverse side effects, most notably the increased risk of bleeding. Moreover, there remains a considerable incidence of arterial thrombosis in a subset of patients receiving currently available drugs. Thus, there is a pressing medical need for novel antiplatelet agents with a more favorable safety profile and less patient resistance. The discovery of novel antiplatelet targets is the matter of intense ongoing research. Recent findings demonstrate the potential of targeting key signaling molecules, including kinases and phosphatases, to prevent platelet activation and aggregation. Here, we offer perspectives to targeting members of the protein tyrosine phosphatase (PTP) superfamily, a major class of enzymes in signal transduction. We give an overview of previously identified PTPs in platelet signaling, and discuss their potential as antiplatelet drug targets. We also introduce VHR (DUSP3), a PTP that we recently identified as a major player in platelet biology and thrombosis. We review our data on genetic deletion as well as pharmacological inhibition of VHR, providing proof-of-principle for a novel and potentially safer VHR-based antiplatelet therapy. [less ▲]

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See detailMarques actives utilisées en télémétrie "poissons"
Tétard, Stéphane; Ovidio, Michaël ULg; Capra, Hervé et al

Scientific conference (2015, April 03)

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See detailTree models with Scikit-Learn: Great models with little assumptions
Louppe, Gilles ULg

Conference (2015, April 03)

This talk gives an introduction to tree-based methods, both from a theoretical and practical point of view. It covers decision trees, random forests and boosting estimators, along with concrete examples ... [more ▼]

This talk gives an introduction to tree-based methods, both from a theoretical and practical point of view. It covers decision trees, random forests and boosting estimators, along with concrete examples based on Scikit-Learn about how they work, when they work and why they work. [less ▲]

Detailed reference viewed: 30 (1 ULg)
See detailLire le futur du passé: villes et paysages de Meuse en projet
Occhiuto, Rita ULg

Conference (2015, April 03)

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See detailQuand la science se mêle de la gestion des eaux pluviales : Les services écosystémiques rendus par l'infrastructure verte
Maréchal, Justine ULg

Conference given outside the academic context (2015)

L'infrastructure verte joue un rôle dominant dans nos villes. Que ce soit d'un point de vue économique, environnemental ou social, chaque fois, cette infrastructure se révèle d'une importance cruciale. La ... [more ▼]

L'infrastructure verte joue un rôle dominant dans nos villes. Que ce soit d'un point de vue économique, environnemental ou social, chaque fois, cette infrastructure se révèle d'une importance cruciale. La présentation s'intéressera dans un premier temps à comprendre les caractéristiques de cette infrastructure verte dans différentes villes belges. Dans un deuxième temps, un parallèle sera fait entre cette structure spatiale des espaces verts et un processus écologique bien précis : la gestion de l'eau pluviale. Pour aborder cette partie, une synthèse de différentes techniques d'aménagement du paysage seront présentées en tant que pistes de réflexion pour une gestion plus intégrée de l'eau de pluie en ville. [less ▲]

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See detailNotizie dalla letteratura sicitaliana, ovvero siciliana e italiana (ed europea)
Curreri, Luciano ULg

Article for general public (2015)

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See detailAnalyse des propriétés anti-tumorales des exosomes endothéliaux dans le cancer du sein suite au transfert du microARN miR-503
Bovy, Nicolas ULg

Doctoral thesis (2015)

L’angiogenèse est un processus essentiel au développement tumoral ainsi qu’à la dissémination des métastases. De plus, il a été démontré ces dernières années que les miARN, des ARN non codant d'une ... [more ▼]

L’angiogenèse est un processus essentiel au développement tumoral ainsi qu’à la dissémination des métastases. De plus, il a été démontré ces dernières années que les miARN, des ARN non codant d'une vingtaine de nucléotides régulant l’expression des gènes au niveau post-transcriptionnel, jouent un rôle important dans divers processus tumoraux. Ils ont en outre été détectés dans plusieurs fluides biologiques, protégés de la dégradation dans des microvésicules, les exosomes. Cependant, à l’heure actuelle, aucune information n’est connue sur le rôle des exosomes endothéliaux et des miARN qu’ils contiennent sur la croissance tumorale. Au cours de ce travail, nous avons pour la première fois mis en évidence l’existence d’un transfert de miARN des cellules endothéliales vers les cellules tumorales par l’intermédiaire d’exosomes. Nous avons ensuite identifié un miARN, miR-503, dont l’export dans ces microvésicules est modifié en conditions tumorales. L’analyse de la fonction du miARN dans les cellules tumorales de cancer du sein montre qu’il possède des propriétés anti-tumorales en réduisant la prolifération et l’invasion. Nous avons également observé que le miR-503 d’origine endothéliale génère les mêmes effets. Pour expliquer ces résultats, deux cibles du miARN ont été identifiées, CCND2 et CCND3. De plus, l’inhibition de ces dernières conduit au même phénotype qu’une surexpression de miR-503. Nous avons ensuite voulu déterminer si le niveau plasmatique de ce miARN était modulé chez des patientes atteintes de cancer du sein. Nos analyses révèlent une augmentation du niveau sanguin de miR-503 à la suite d’un traitement par chimiothérapie néoadjuvante. Nous avons de plus observé que des cellules endothéliales soumises aux mêmes agents chimiothérapeutiques sécrètent activement du miR-503 dans leurs exosomes. Il semble également que le changement phénotypique induit par miR-503 sur les cellules tumorales modifie leur production en facteurs angiogènes ce qui mène, en retour, à une inhibition de l’angiogenèse. Ces résultats montrent que miR-503 est un miARN anti-tumoral sécrété dans les exosomes de cellules endothéliales. Celui-ci provoque l’inhibition de la prolifération et de l’invasion de cellules tumorales du cancer du sein en ciblant CCND2 et CCND3. Ce processus pourrait être complémentaire des effets directs générés par la chimiothérapie sur la tumeur et favoriser la réponse de l’hôte dans le traitement de la maladie. [less ▲]

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See detailDoes high school program choice affect academic performance? Evidence for Economics
Lefevre, Mélanie ULg

Conference (2015, April 02)

This study evaluates the impact of the choice of the Economics elective course in secondary school on the performance in Economics at the University level. While several studies look at the impact on ... [more ▼]

This study evaluates the impact of the choice of the Economics elective course in secondary school on the performance in Economics at the University level. While several studies look at the impact on performance of the number of hours of mathematics in secondary school, less has been made regarding the impact of the secondary school Economics program. We match survey data from 360 students enrolled in the first year of the bachelors program in HEC-Management School of University of Liège, with administrative data and exam results. The methodological challenge is that students who choose Economics elective course in secondary school are likely to be different, in terms of motivation, from other students. To get rid of this potential bias, we approximate motivation using self-reported reasons for the choice of the elective courses, but also participation to non-mandatory tests and preparations before the exam. We also control for several individual characteristics (socio-economic background, age, gender, secondary school fixed effect, etc.) in order to compare students with similar abilities. Preliminary analysis shows that students who have chosen Economics elective course in the last year of secondary school do not perform better, or worse, at their University Economics exam, when controlling for the number of hours of mathematics they had in secondary school, as well as other individual characteristics. However, they are less likely to report their bachelor Economics course as being “difficult”. Overconfidence of students with higher previous economic knowledge may explain why they do not perform better than their peers. [less ▲]

Detailed reference viewed: 18 (4 ULg)