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See detailLifetime stability study of a NIR hyperspectral imaging system
Eylenbosch, Damien ULg; Bodson, Bernard ULg; Baeten, Vincent et al

Conference (2016, July)

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See detailApplication of NIR hyperspectral imaging combined to chemometrics to assess the impact of tillage on the root system development of a winter wheat crop
Fraipont, Guillaume ULg; Eylenbosch, Damien ULg; Baeten, Vincent et al

Poster (2016, July)

This poster presents de results of a study of the influence of tillage on the root development of a winter wheat crop. The originality of this research lies in the application of an innovative root ... [more ▼]

This poster presents de results of a study of the influence of tillage on the root development of a winter wheat crop. The originality of this research lies in the application of an innovative root quantification method based on the near infrared hyperspectral imaging. [less ▲]

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See detailInterspecific variation of warning calls in piranhas: comparative analysis
Mélotte, Geoffrey ULg; Michel, Christian ULg; Vigouroux, Régis et al

Poster (2016, July)

Fish sounds are often considered as species-specific with unique temporal and spectral features. Differences between acoustic signals of closely related species could be considered as pre-zygotic barrier ... [more ▼]

Fish sounds are often considered as species-specific with unique temporal and spectral features. Differences between acoustic signals of closely related species could be considered as pre-zygotic barrier and could be related to the evolutionary history of the species. In the present study, sounds were recorded and compared in eight piranha species (Serrasalmus elongatus, Serrasalmus marginatus, Serrasalmus compressus, Serrasalmus manueli, Serrasalmus spilopleura, Serrasalmus rhombeus, Serrasalmus eigenmanni and Pygocentrus nattereri) in order to evaluate the potential role of acoustic communication as a driving force in the clade diversification. The same kind of sound-producing mechanism was found in all the species: sonic muscles originate on vertebrae and attach to a tendon surrounding ventrally the bladder. Contractions of the sound-producing muscles force swimbladder vibration. Having the same kind of sound-producing mechanism, the calling features of the eight piranha species show logically many common characteristics. In all the species, the calls are harmonic sounds composed of several pulses without inter-pulse interval. It was possible to discern species-specific sounds, but the differences among species could be, in part, explained by the size. Only the sounds of S. elongatus and S. manueli are really distinguishable from the other species. Serrasalmus elongatus differed by having a higher number of pulses and high-pitched fundamental frequency, whereas S. manueli differed by having long pulse periods and a low fundamental frequency. In the framework of this study, acoustic communication cannot be considered as the main driving force in the diversification process of piranhas. Behavioral studies are however needed to clearly understand the eventual role of the calls during the spawning events. [less ▲]

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See detailTemporal habitat shift of a polymorphic newt species under predation risk
Winandy, Laurane ULg; Colin, Mélanie; Denoël, Mathieu ULg

in Behavioral Ecology (2016), 27(4), 1025-1032

The temporal partitioning hypothesis suggests that the evolution of different diel activity rhythms in animals might facilitate the coexistence between prey and predators. However, the temporal shift of ... [more ▼]

The temporal partitioning hypothesis suggests that the evolution of different diel activity rhythms in animals might facilitate the coexistence between prey and predators. However, the temporal shift of habitat use induced by predation has rarely been observed. The study of such a mechanism is particularly relevant for introduced species because it might explain how native species can persist or decline in response to the presence of alien species. The introduction of fish into ponds inhabited by amphibians has severe consequences for their occurrence and abundance. Fish particularly affect an alternative newt phenotype, the paedomorph, which does not undergo metamorphosis and maintains larval traits such as gills at the adult stage. In a laboratory design, we assessed the diel patterns of habitat use in the 2 distinct morphological phenotypes of palmate newt (Lissotriton helveticus) in the presence or absence of goldfish (Carassius auratus). Both newt phenotypes avoided a risky habitat more in the presence than in the absence of fish. This habitat shift was more pronounced during the daytime (i.e., when the risk could be considered higher for the newts) than during nighttime. However, in contrast to metamorphs, paedomorphs showed less adaptive changes according to temporal risk and remained in their shelter for most of the time. Temporal and habitat partitioning at the diel scale between native and alien species might promote their coexistence, but diel change can also imply a cost in the overall reduction of the time allocated to essential activities, showing that species interactions remain complex. [less ▲]

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See detailPhilosophie et esthétique de la modernité: Approches phénoménologiques et sociologiques
Hagelstein, Maud ULg; Zincq, Aurélien ULg

in Bulletin d'Analyse Phénoménologique (2016), 12 (2016)(4),

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See detailCognitive processes across anxiety disorders related to intolerance of uncertainty: Clinical Review
Vander Haegen, Marie ULg; Etienne, Anne-Marie ULg

in Cogent Psychology (2016), 3

Abstract: Objective: Being a relatively recent concept, the intolerance of uncertainty (IU) suffers from inconsistent definitions and conceptual overlap. The core objective of the study is to clarify its ... [more ▼]

Abstract: Objective: Being a relatively recent concept, the intolerance of uncertainty (IU) suffers from inconsistent definitions and conceptual overlap. The core objective of the study is to clarify its clinical manifestations and its involved cognitive processes. Method: The procedure is based on algorithms (equations of keywords) encoded simultaneously in databases (Scopus, PubMed, and PsycArticles). Results are filtered by the year (range of 10 years [2005–2015] because it is a recent concept) and the relevance of abstracts. Once the studies are appraised, results are categorized in two groups: studies which examine the IU in a clinical perspective (relations with one or several anxiety disorders) (cluster A) and those which measure the IU through a cognitive perspective (cognition, metacognition) (cluster B). Results: 66 results are retrieved: 50 results concern the cluster A and 16 examine the cluster B. The state of the IU varies between studies (e.g. predictor and mediator), which make comparisons difficult. Notwithstanding, the IU construct seems to be a broad transdiagnostic maintaining risk factor involved in a range of psychological disorders. Conclusion: This clustering supported that researchers and clinicians may benefit from incorporating IU within cognitive and computational research design and as a specific treatment target. [less ▲]

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See detailBoosting shape classifiers accuracy by considering the inverse shape
Pierard, Sébastien ULg; Lejeune, Antoine ULg; Van Droogenbroeck, Marc ULg

in Journal of Pattern Recognition Research (2016), 11(1), 41-54

Many techniques exist for describing shapes. These techniques almost exclusively consider the contour or the inside of the shape; the major problem for describing the outside of a shape, or inverse shape ... [more ▼]

Many techniques exist for describing shapes. These techniques almost exclusively consider the contour or the inside of the shape; the major problem for describing the outside of a shape, or inverse shape, being that it has an infinite extension. In this paper, we show how to adapt two shape descriptors, one region based, the Cover By Rectangles, and one transform based, the Zernike moments, to be applicable to the inverse shape. We analyze their properties, and show how to deal with the infinite extension of the inverse shape. Then, we apply these descriptors to shape classification and compare representations that use the shape, its inverse, or both. Our experiments establish that, for shape classification, a representation integrating the inverse shape often outperforms a representation restricted to the shape. This opens the path for better techniques that could use, as a rule of thumb, both the representations of a shape and its inverse for the purpose of classification. [less ▲]

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See detailLeveraging orientation knowledge to enhance human pose estimation methods
Azrour, Samir ULg; Pierard, Sébastien ULg; Van Droogenbroeck, Marc ULg

in Articulated Motion and Deformable Objects AMDO 2016 (2016, July)

Predicting accurately and in real-time 3D body joint positions from a depth image is the cornerstone for many safety, biomedical, and entertainment applications. Despite the high quality of the depth ... [more ▼]

Predicting accurately and in real-time 3D body joint positions from a depth image is the cornerstone for many safety, biomedical, and entertainment applications. Despite the high quality of the depth images, the accuracy of existing human pose estimation methods from single depth images remains insufficient for some applications. In order to enhance the accuracy, we suggest to leverage a rough orientation estimation to dynamically select a 3D joint position prediction model specialized for this orientation. This orientation estimation can be obtained in real-time either from the image itself, or from any other clue like tracking. We demonstrate the merits of this general principle on a pose estimation method similar to the one used with Kinect cameras. Our results show that the accuracy is improved by up to 45.1 %, with respect to a method using the same model for all orientations. [less ▲]

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See detailSPARC Report on the Mystery of Carbon Tetrachloride
Ahmadzai, H; Bock, R P; Burkholder, J B et al

in Liang, Qing; Newman, Paul A; Reimann, Stefan (Eds.) SPARC Report on the Mystery of Carbon Tetrachloride (2016)

The Montreal Protocol (MP) controls the production and consumption of carbon tetrachloride (CCl4 or CTC) and other ozone-depleting substances (ODSs) for emissive uses. CCl4 is a major ODS, accounting for ... [more ▼]

The Montreal Protocol (MP) controls the production and consumption of carbon tetrachloride (CCl4 or CTC) and other ozone-depleting substances (ODSs) for emissive uses. CCl4 is a major ODS, accounting for about 12% of the globally averaged inorganic chlorine and bromine in the stratosphere, compared to 14% for CFC-12 in 2012. In spite of the MP controls, there are large ongoing emissions of CCl4 into the atmosphere. Estimates of emissions from various techniques ought to yield similar numbers. However, the recent WMO/UNEP Scientific Assessment of Ozone Depletion [WMO, 2014] estimated a 2007-2012 CCl4 bottom-up emission of 1-4 Gg/year (1-4 kilotonnes/year), based on country-by-country reports to UNEP, and a global top-down emissions estimate of 57 Gg/ year, based on atmospheric measurements. This 54 Gg/year difference has not been explained. In order to assess the current knowledge on global CCl4 sources and sinks, stakeholders from industrial, governmental, and the scientific communities came together at the “Solving the Mystery of Carbon Tetrachloride” workshop, which was held from 4-6 October 2015 at Empa in Dübendorf, Switzerland. During this workshop, several new findings were brought forward by the participants on CCl4 emissions and related science. • Anthropogenic production and consumption for feedstock and process agent uses (e.g., as approved solvents) are reported to UNEP under the MP. Based on these numbers, global bottom-up emissions of 3 (0-8) Gg/year are estimated for 2007-2013 in this report. This number is also reasonably consistent with this report’s new industry-based bottom-up estimate for fugitive emissions of 2 Gg/year. • By-product emissions from chloromethanes and perchloroethylene plants are newly proposed in this report as significant CCl4 sources, with global emissions estimated from these plants to be 13 Gg/year in 2014. • This report updates the anthropogenic CCl4 emissions estimation as a maximum of ~25 Gg/year. This number is derived by combining the above fugitive and by-product emissions (2 Gg/year and 13 Gg/year, respectively) with 10 Gg/year from legacy emissions plus potential unreported inadvertent emissions from other sources. • Ongoing atmospheric CCl4 measurements within global networks have been exploited for assessing regional emissions. In addition to existing emissions estimates from China and Australia, the workshop prompted research on emissions in the U.S. and Europe. The sum of these four regional emissions is estimated as 21±7.5a Gg/year, but this is not a complete global accounting. These regional top-down emissions estimates also show that most of the CCl4 emissions originate from chemical industrial regions, and are not linked to major population centres. • The total CCl4 lifetime is critical for calculating top-down global emissions. CCl4 is destroyed in the stratosphere, oceans, and soils, complicating the total lifetime estimate. The atmospheric lifetime with respect to stratospheric loss was recently revised to 44 (36-58) years, and remains unchanged in this report. New findings from additional measurement campaigns and reanalysis of physical parameters lead to changes in the ocean lifetime from 94 years to 210 (157-313) years, and in the soil lifetime from 195 years to 375 (288-536) years. • These revised lifetimes lead to an increase of the total lifetime from 26 years in WMO [2014] to 33 (28-41) years. Consequently, CCl4 is lost at a slower rate from the atmosphere. With this new total lifetime, the global top-down emissions calculation decreases from 57 (40-74) Gg/year in WMO [2014] to 40 (25-55) Gg/year. This estimate is relatively consistent with the independent gradient top-down emissions of 30 (25-35) Gg/year, based upon differences between atmospheric measurements of CCl4 in the Northern and Southern Hemispheres. In addition, this new total lifetime implies an upper limit of 3-4 Gg/year of natural emissions, based upon newly reported observations of old air in firn snow. These new CCl4 emissions estimates from the workshop make considerable progress toward closing the emissions discrepancy. The new industrial bottom-up emissions estimate (15 Gg/year total) includes emissions from chloromethanes plants (13 Gg/year) and feedstock fugitive emissions (2 Gg/year). When combined with legacy emissions and unreported inadvertent emissions, this could be up to 25 Gg/year. Top-down emissions estimates are: global 40 (25-55) Gg/year, gradient 30 (25-35) Gg/year, and regional 21 (14-28) Gg/year. While the new bottom-up value is still less than the aggregated top-down values, these estimates reconcile the CCl4 budget discrepancy when considered at the edges of their uncertainties. [less ▲]

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See detailPassive flutter suppression using a nonlinear tuned vibration absorber
Verstraelen, Edouard ULg; Gourc, Etienne ULg; Kerschen, Gaëtan ULg et al

Poster (2016, July)

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was ... [more ▼]

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was turning the initial super-critical bifurcation into a sub-critical one. This work shows numerically that adding a nonlinear restoring force to the absorber can restore the su- percritical behaviour of the bifurcation and further reduce the post-instability limit cycle amplitude. [less ▲]

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See detailApplications of the multiple timescale spectral analysis in wind engineering
Denoël, Vincent ULg

in Zingoni, Alphose (Ed.) Proceedings of the Sixth International Conference on Structural Engineering, Mechanics and Computation (2016, July)

The random response of civil engineering structures to the buffeting action of wind loads is typically composed of several components, usually referred to as the background component, in the low fre ... [more ▼]

The random response of civil engineering structures to the buffeting action of wind loads is typically composed of several components, usually referred to as the background component, in the low fre- quency zone and the resonant component(s) in the neighborhood of modal natural frequencies. It has become customary to study separately and add the contributions of these components to the total response, at least as far as the second order response (variance of structural responses) is concerned. Such a decomposition exists but is less usual for the computation of covariances of modal coordinates or of structural displacements, which are in turn necessary for the determination of internal stresses. The question of such a decomposition also holds for nonlinear systems, or even for the higher statistical moments of a linear structural system, should the response be non Gaussian. With very wide ranges of applicability, the Multiple Timescale Spectral Analysis summarizes under a unified framework recent works aiming at the development of such decompositions. This paper briefly pictures this particular theory based on perturbation methods, and provides illustrations of its applicability to the problems cited above. [less ▲]

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See detailUnveiling new stellar companions from the EXOZODI survey : follow up
Marion, Lindsay ULg; Absil, Olivier ULg; Ertel, Steve et al

Poster (2016, June 30)

In 2012, we have conducted a survey of nearby main sequence stars with VLTI/PIONIER to search for the presence of circumstellar dust. We focused on the use of the closure phases and the square ... [more ▼]

In 2012, we have conducted a survey of nearby main sequence stars with VLTI/PIONIER to search for the presence of circumstellar dust. We focused on the use of the closure phases and the square visibilities in a combined way to search for faint companions around the whole sample. In this process, we found four new stellar companions, for which we conducted follow-up observations in 2014. This follow up allows us to confirm the four detections, and to detect another new companion. Only the case of HD202730 remains ambiguous. [less ▲]

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See detailSmart co-phasing system for segmented mirror telescopes
Simar, Juan Felipe ULg; Stockman, Yvan ULg; Surdej, Jean ULg

Poster (2016, June 30)

One of the main challenges in space observations is to observe always fainter and more compact objects. This can be achieved by increasing the telescope diameters. So, increasing the primary mirror ... [more ▼]

One of the main challenges in space observations is to observe always fainter and more compact objects. This can be achieved by increasing the telescope diameters. So, increasing the primary mirror diameters of the telescopes is the challenge solution but it is technically impossible to manufacture monolithic mirrors larger than 10m in diameter. The use of segmented mirrors thus becomes mandatory. This paper describes the results of a light co-phasing setup mounted in laboratory. This setup is able to correct a piston from 200μm to 15 nm based on coarse (200μm to 300nm) and fine (300nm to 15nm) measurement methods. Both measurements are then chained in a feedback system in order to completely co-phase and keep the segments aligned. [less ▲]

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See detailIntegrating roots into a whole plant network of flowering time genes in Arabidopsis thaliana
Bouché, Frédéric ULg; D'Aloia, Maria; Tocquin, Pierre ULg et al

in Scientific Reports (2016), 6

Molecular data concerning the involvement of roots in the genetic pathways regulating floral transition are lacking. In this study, we performed global analyses of the root transcriptome in Arabidopsis in ... [more ▼]

Molecular data concerning the involvement of roots in the genetic pathways regulating floral transition are lacking. In this study, we performed global analyses of the root transcriptome in Arabidopsis in order to identify flowering time genes that are expressed in the roots and genes that are differentially expressed in the roots during the induction of flowering. Data mining of public microarray experiments uncovered that about 200 genes whose mutations are reported to alter flowering time are expressed in the roots (i.e. were detected in more than 50% of the microarrays). However, only a few flowering integrator genes passed the analysis cutoff. Comparison of root transcriptome in short days and during synchronized induction of flowering by a single 22-h long day revealed that 595 genes were differentially expressed. Enrichment analyses of differentially expressed genes in root tissues, gene ontology categories, and cis-regulatory elements converged towards sugar signaling. We concluded that roots are integrated in systemic signaling, whereby carbon supply coordinates growth at the whole plant level during the induction of flowering. This coordination could involve the root circadian clock and cytokinin biosynthesis as a feed forward loop towards the shoot. [less ▲]

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See detailVers une transition durable des quartiers urbains. Formulation d'un modèle d'innovation applicable à la politique des quartiers.
Ruelle, Christine ULg

Doctoral thesis (2016)

La thèse démontre que la transition durable se produit de manière très inégale dans les quartiers urbains. Elle explore alors la question de l'action publique et de la manière dont les pouvoirs publics ... [more ▼]

La thèse démontre que la transition durable se produit de manière très inégale dans les quartiers urbains. Elle explore alors la question de l'action publique et de la manière dont les pouvoirs publics pourraient soutenir cette transition durable dans les quartiers. En particulier, le potentiel de la "politique des quartiers" est analysé et des amélioration sont proposées. La recherche-action est ensuite mobilisée pour pour enrichir cette politique de nouveaux instruments d'action, plus adaptés pour engager les habitants dans la dynamique de transition durable de leur quartier. [less ▲]

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See detailNumerical Assessment of Non-Lethal Projectile Thoracic Impacts
Nsiampa Ndompetelo, ULg

Doctoral thesis (2016)

Anti-personnel Non-Lethal Weapons (NLW) are weapons that are designed to impart sufficient effect onto a person in order to deter uncivil, suspect or hazardous behaviour with a low probability of severe ... [more ▼]

Anti-personnel Non-Lethal Weapons (NLW) are weapons that are designed to impart sufficient effect onto a person in order to deter uncivil, suspect or hazardous behaviour with a low probability of severe or fatal injury. They are used both by military and law enforcement in situations of low-intensity conflicts like riot control, access denial, peacekeeping missions i.e. situations where the use of lethal force is not appropriate nor desired. The most used of these weapons are the Kinetic Energy Non-Lethal Weapons (KENLW). The underlying principle of KENLW is to launch a projectile with a mass varying between 5 g and 140 g at initial velocity up to 160 m/s, which by a mechanical action on the target, will cause enough physical pain to incapacitate or repel the target. But their use is not without risk as in practice, the impacts of Kinetic Energy Non-Lethal (KENL) projectiles on the human thorax resulted in injuries, some of the them were severe even fatal. Therefore there is a need to develop methods of assessment. These assessment methods are essential in order to help deciders in charge of non- lethal weapon procurement with technical information so they can choose the best product (weapon or projectile) available on the market; to give relevant information to the manufacturers in either developing new weapons or projectiles that are more effective, or improving the existing ones, and finally to the end-users (military or police forces) of these weapons, information on operational distance of engagement. In practice, it has been observed that the thorax is the body region where the impacts of KNL projectiles led to more significant injuries than other parts of the body apart from the head which is never targeted at. Therefore in the present thesis, only assessment of thoracic impacts is investigated. Besides tests on PMHS (Post Mortem Human Subjects), animals or human surrogates, one powerful tool that is used nowadays to assess the thoracic impacts is the finite element method (FEM). It has many advantages like the capability of accounting for complex geometries or complex material modelling and its cost-effectiveness. It also gives insight into physical variables (stresses, strains,...) inside the material which are inaccessible by other means. It helps for a better understanding of the injury mechanism. Moreover, it helps to reduce cadavers or animal testings. In the present thesis, only FEM is considered as tool for injury risk assessment. On the one hand, a thorax finite element (FE) model, the SHTIM (Surrogate Human Thorax Impact Model) has been developed for the injury risk assessment. Number of assumptions has been made relative to the thorax geometry and the material characteristics are based on literature. The model has been validated thanks to the results of experiments carried out by professor C. Bir. A viscous injury criterion was defined as the parameter relevant for the occurrence of the thorax skeletal injury. This criterion is used in the present thesis for the prediction of the thoracic injury outcome. On the other hand, FE models of six projectiles have been developed where most of material characteristics were taken from the literature. For the 40 mm sponge grenades, a new method of characterizing the deformable nose has been developed. The projectile FE models were validated by comparing numerical results to experimental results obtained from real firing tests of the projectile against a rigid wall structure. These firing tests have been performed within the Department ABAL. Good correspondence was found. Once the thorax FE model and the projectile FE models validated, numerical simulations of the impact between the thorax and the projectile were performed. Using the viscous injury criterion, risk assessment of the thorax impacts was carried out. For each projectile, a critical velocity was determined which thanks to the retardation can be linked to a minimum firing distance, the safe distance. This is the distance below which an impact will result in a higher risk of skeletal thoracic injury. This information is very important for the end-users (military, police). Moreover comparison of the performance of different KENL projectiles was carried out. Few years ago, the Department ABAL acquired a thorax mechanical surrogate, the 3RBID (3 Rib Ballistic Impact Dummy) for the prediction of thoracic injury. It was an opportunity to compare both surrogates and to see if the SHTIM results are consistent with the 3RBID results. Good correspondence has been found especially for projectiles with larger diameter like the 40 mm sponge grenades. [less ▲]

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See detailA Selective and Highly Sensitive MIR Photoacuostic Sensor for Trace Gas Monitoring
Lassen, M; Lamar, L; Balslev-Harder, D et al

Conference (2016, June 28)

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See detailL'acétonémie : un bien ou un mal nécessaire pour la vache laitière ?
Beckers, Yves ULg

Conference given outside the academic context (2016)

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