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See detailA short dive into the complexity of Jupiter’s aurorae - invited
Bonfond, Bertrand ULg

Conference (2015, April 13)

Aurorae are the atmospheric signatures of energetic processes taking place far in the magnetosphere. One of the most important results brought by high resolution imaging of the UV aurorae at Jupiter is ... [more ▼]

Aurorae are the atmospheric signatures of energetic processes taking place far in the magnetosphere. One of the most important results brought by high resolution imaging of the UV aurorae at Jupiter is the realization that there isn’t such a thing as «the aurora» at Jupiter; as these light emissions appear to arise from a variety of processes. Some are related to the interaction of the magnetospheric plasma with the moons (the satellite footprints). Others are linked with the radial motion of flux tubes through centrifugal instabilities (the injection auroral signatures). Some diffuse emissions are connected with wave-particle interaction (the equatorward diffuse emissions). Another feature is associated with the magnetosphere-ionosphere coupling (the main emission/oval). Some auroral spots are related to internally driven reconnection (the polar dawn spots). Finally, the polar-most emissions remain to be understood and this list is still incomplete. In order to illustrate the discrepancies between these various features, I will show a set of recent results derived from the analysis of Hubble Space Telescope observations. For example, I will compare the vertical profile of satellite footprints and the main emissions, and show that the energy population of the precipitating particles varies from feature to feature. Moreover, even within a single feature, spatial variations do exist. As an example, I will characterize the dawn-dusk brightness discrepancy of the main emissions and discuss its implication regarding the magnetospheric currents. And finally, the dynamics of the features also helps differentiating one type of aurora from another. This will be shown through the description of the morphological evolution of the transient flares in the polar region. [less ▲]

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See detailPreliminary results for a hydrogen maser cavity in the TE111 mode
Van Der Beken, Emeline ULg; Léonard, Daniel; Counet, Arnaud et al

Poster (2015, April 13)

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See detailEGU2015 - ENSO forecast using a wavelet-based mode decomposition
Deliège, Adrien ULg; Nicolay, Samuel ULg; Fettweis, Xavier ULg

Conference (2015, April 13)

The aim of this work is to introduce a new method for forecasting major El Niño/ La Niña events with the use of a wavelet-based mode decomposition. These major events are related to sea surface ... [more ▼]

The aim of this work is to introduce a new method for forecasting major El Niño/ La Niña events with the use of a wavelet-based mode decomposition. These major events are related to sea surface temperature anomalies in the tropical Pacific Ocean: anomalous warmings are known as El Niño events, while excessive coolings are referred as La Niña episodes. These climatological phenomena are of primary importance since they are involved in many teleconnections ; predicting them long before they occur is therefore a crucial concern. First, we perform a wavelet transform (WT) of the monthly sampled El Niño Southern Oscillation 3.4 index (from 1950 to present) and compute the associated scale spectrum, which can be seen as the energy carried in the WT as a function of the scale. It can be observed that the spectrum reaches five peaks, corresponding to time scales of about 7, 20, 31, 43 and 61 months respectively. Therefore, the Niño 3.4 signal can be decomposed into five dominant oscillating components with time-varying amplitudes, these latter being given by the modulus of the WT at the associated pseudo-periods. The reconstruction of the index based on these five components is accurate since more than 93% of the El Niño/ La Niña events of the last 60 years are recovered and no major event is erroneously predicted. Then, the components are smoothly extrapolated using polynomials and added together, giving so several years forecasts of the Niño 3.4 index. In order to increase the reliability of the forecasts, we perform several months hindcasts (i.e. retroactive probing forecasts) which can be validated with the existing data. It turns out that most of the major events can be accurately predicted up to three years in advance, which makes our methodology competitive for such forecasts. Finally, we discuss the El Niño conditions currently undergone and give indications about the next La Niña event. [less ▲]

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See detailSoil porosity in agricultural context: A review of measurement techniques at various scales
Garré, Sarah ULg; Chelin, Marie ULg; Luong, Jeanne ULg et al

Poster (2015, April 13)

Soil compaction was identified by European Commission as one of the eight main threats for agricultural soils. In order to address this issue, measurements of soil porosity are critical. However, there ... [more ▼]

Soil compaction was identified by European Commission as one of the eight main threats for agricultural soils. In order to address this issue, measurements of soil porosity are critical. However, there are as many techniques to measure as there are definitions of porosity. A single method is not sufficient to obtain a complete image of the soil porosity at various scales and encompassing different levels of complexity. Each existing method is characterized by a unique combination of a specific level of complexity, resolution and scale of measurement. In this review, we started by defining the basic terms linked to soil porosity in an agricultural context. Then we give an overview of relevant measurement techniques, from classical methods to recent advances. We present their advantages and disadvantages, the scales of measurement, the resolution, the expected accuracy and the susceptibility to errors. This work aims at guiding the choice for the best (combination of) technique(s) to answer questions related to agricultural soil porosity, categorizing techniques according to the parameters they focus on: from total porosity over pore size distribution, structure and connectivity up to the quantification of spatio-temporal dynamics. [less ▲]

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See detailCibo e Islam.
Mescoli, Elsa ULg

Conference given outside the academic context (2015)

Séminaire organisé dans le cadre d'un cours de formation pour professionnels. Thématique: le rapport à la nourriture dans la religion islamique (interdictions, indications, rituels etc.).

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See detailWhat is the professional profile of patients in phoniatrics?
Remacle, Angélique ULg; Petitfils, Cloé; LEJEUNE, LIONEL ULg et al

Conference (2015, April 10)

Objective. Research has paid increased attention to occupational voice disorders. This study describes the occupational status of patients examined in the Department of Otorhinolaryngology at Liège ... [more ▼]

Objective. Research has paid increased attention to occupational voice disorders. This study describes the occupational status of patients examined in the Department of Otorhinolaryngology at Liège University Hospital (Belgium) from 2009 to 2013. Study design. Retrospective study. Methods. The sex, age, diagnosis and occupational status were identified for 1,079 patients who were examined for a voice problem (754 women and 325 men; ages 4 to 93). The diagnosis was established using videolaryngostroboscopy. For patients who were employed, we identified (1) the numerically most frequent professionals, and (2) the professionals most at risk of consulting for their voice, based on the distribution of these professions among all workers living in French-speaking Belgium. Results. 11% of patients were unemployed, 15% were students, 20% were retired, and 54% were workers. In decreasing order of frequency, the most commonly seen professionals were teachers, office workers, artists (singers, actors, and musicians), storekeepers and marketing representatives, managers, domestic workers, and laborers. Regarding their distribution in the working population, the workers at greatest risk of consulting were artists, music teachers, counselors, sports coaches, psychologists, switchboard operators, journalists, and teachers. Nodules are the most common pathologies, encountered in 16.8% of the workers and 42.8% of the students who consulted the Department of Otorhinolaryngology for dysphonia. Conclusion. Prevention is needed both for the professions that seek medical help in the largest numbers (teachers) and for those that are at highest risk of consulting (artistic professions). In addition, teachers must be informed of the need to seek help as soon as voice problems appear. Level of evidence: 2b [less ▲]

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See detailChallenges of Sustainable and Commercial Aquaponics
Goddek, Simon; Delaide, Boris ULg; Mankasingh, Utra et al

in Sustainability (2015), 7

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See detailMéthode ethnographique et science sociocriminologique. Le cas des groupements de jeunes.
Collin, Jonathan ULg

Conference given outside the academic context (2015)

ARGUMENT : Comment allier objet d'intérêt criminologique et méthodes de recherche ? Comment construire une méthode pertinente pour rendre compte, par exemple, de la réalité des groupes de jeunes, en ce ... [more ▼]

ARGUMENT : Comment allier objet d'intérêt criminologique et méthodes de recherche ? Comment construire une méthode pertinente pour rendre compte, par exemple, de la réalité des groupes de jeunes, en ce compris ce que certains praticiens et chercheurs nomment "les bandes" ? La réponse se trouve peut-être dans la méthode ethnographique, dont nous savons qu'elle fut utilisée par les sociologues dits de l'Ecole de Chicago et qu'elle est encore la base méthodologique des recherches en anthropologie et de certaines études sociologiques. Pourrait-on alors parler "d'ethnocriminologie", dans le sens où l'on étudierait un phénomène d'intérêt criminologique à travers la méthode ethnographique ? Plus largement, quelle place la criminologie fait-elle à l'anthropologie et à l'ethnographie ? [less ▲]

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See detailOptimal Enforcement of Competition Policy: The Commitments Procedure under Uncertainty
Gautier, Axel ULg

Scientific conference (2015, April 09)

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See detailImproved spectral fitting of nitrogen dioxide from OMI in the 405-465 nm window
van Geffen, J H G M; Boersma, K F; Van Roozendael, M et al

in Atmospheric Measurement Techniques (2015), 8

An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405–465 nm spectral region is presented. Since the launch of OMI on board NASA’s EOS-Aura ... [more ▼]

An improved nitrogen dioxide (NO2) slant column density retrieval for the Ozone Monitoring Instrument (OMI) in the 405–465 nm spectral region is presented. Since the launch of OMI on board NASA’s EOS-Aura satellite in 2004, differential optical absorption spectroscopy (DOAS) retrievals of NO2 slant column densities have been the starting point for the KNMI DOMINO and NASA SP NO2 vertical column data as well as the OMI NO2 data of some other institutes. However, recent intercomparisons between NO2 retrievals from OMI and other UV/Vis and limb spectrometers, as well as ground-based measurements, suggest that OMI stratospheric NO2 is biased high. This study revises and, for the first time, fully documents the OMI NO2 retrieval in detail. The representation of the OMI slit function to convolve high-resolution reference spectra onto the relevant spectral grid is improved. The window used for the wavelength calibration is optimised, leading to much-reduced fitting errors. Ozone and water vapour spectra used in the fit are updated, reflecting the recently improved knowledge of their absorption cross section in the literature. The improved spectral fit also accounts for absorption by the O2–O2 collision complex and by liquid water over clearwater areas. The main changes in the improved spectral fitting result from the updates related to the wavelength calibration: the RMS error of the fit is reduced by 23% and the NO2 slant column by 0.85 1015 molec cm-2, independent of latitude, solar zenith angle and NO2 value. Including O2–O2 and liquid water absorption and updating the O3 and water vapour cross-section spectra further reduces NO2 slant columns on average by 0.35 1015 molec cm-2, accompanied by a further 9% reduction in the RMS error of the fit. The improved OMI NO2 slant columns are consistent with independent NO2 retrievals from other instruments to within a range that can be explained by photochemically driven diurnal increases in stratospheric NO2 and by small differences in fitting window and approach. The revisions indicate that current OMI NO2 slant columns suffered mostly from an additive positive offset, which is removed by the improved wavelength calibration and representation of the OMI slit function. It is therefore anticipated that the improved NO2 slant columns are most important to retrievals of spatially homogeneous stratospheric NO2 rather than to heterogeneous tropospheric NO2. [less ▲]

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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 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 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 detailA novel procedure to measure shrinkage-free tree-rings from very large wood samples combining photogrammetry, high-resolution image processing, and GIS tools
Latte, Nicolas ULg; Beeckman, Hans; Bauwens, Sébastien ULg et al

in Dendrochronologia (2015)

We present a new procedure for wood sampling and tree-ring measurement that can be used for dendrochronological investigation on very large trees, specifically adapted for tropical rainforest species ... [more ▼]

We present a new procedure for wood sampling and tree-ring measurement that can be used for dendrochronological investigation on very large trees, specifically adapted for tropical rainforest species. This procedure takes advantage of the technological developments in computing, image processing, and geographic information systems (GIS) to overcome the technical limitations of the currently used methods. Two types of wood samples can be used (stem disks and/or bars) depending on tree diameter, and the difficulty of ring delineation and crossdating. Bars are an effective compromise between cores and disks. We developed an application combining several programs (Excel, R, ArcGIS, and MapWinGIS) in the Windows operating system for semi-automatic measurement of tree-rings from high-resolution images of the sanded cross-section. Using an innovative method to reverse the wood shrinkage resulting from the drying process, tree-ring measurement can be performed on shrinkage-free images, thus referring to the actual growth of the tree. [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 detailMarques actives utilisées en télémétrie "poissons"
Tétard, Stéphane; Ovidio, Michaël ULg; Capra, Hervé et al

Scientific conference (2015, April 03)

Detailed reference viewed: 4 (0 ULg)