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See detailSeismic Behaviour of Thin-Bed Layered Unreinforced Clay Masonry Frames with T- or L-Shaped Piers
Mordant, Christophe ULg; Dietz, Matt; Taylor, Colin et al

in Taucer, Fabio; Apostolska, Roberta (Eds.) Experimental Research in Earthquake Engineering - EU-SERIES Concluding Workshop (2015)

According to current standards, the use of unreinforced masonry is only recommended in regions of low to moderate seismicity as a resisting system to carry earthquake-induced horizontal forces. This ... [more ▼]

According to current standards, the use of unreinforced masonry is only recommended in regions of low to moderate seismicity as a resisting system to carry earthquake-induced horizontal forces. This requirement is however felt as rather conservative and leading to uneconomical constructive solutions, in particular for low seismic regions. Moreover, the seismic analysis of masonry structures has to be performed along two main perpendicular directions, usually neglecting the contribution of wall elements perpendicular to the seismic action. Horizontal elements (spandrel, etc.) are also commonly disregarded. In such a context, the present contribution provides an overview of experimental results obtained from shake table tests on unreinforced masonry frames carried out in the EQUALS Laboratory of Bristol University in order to assess, and possibly enhance, current design rules. The study is focused on the contribution of walls perpendicular to the seismic action and on the influence of the frame effect induced by the coupling of the walls through horizontal reinforced concrete elements, such as lintels and floor slabs. Another point of interest of the study is the influence of the gravity loading situation, comparing a floor slab supported by the shear walls as well as by the perpendicular elements, with a floor slab supported by the perpendicular walls only. Tests are performed on walls constructed with units and construction methods typical of the North-Western European region. [less ▲]

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See detailUse of NIR-HIS and dichotomist classification tree based on SVMDA models in order to discriminate roots and crop residues of winter wheat
Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio; Baeten, Vincent et al

in EARSeL 2015: 9th EARSeL SIG Imaging Spectroscopy workshop, Luxembourg 14-16 April 2015 (2015, April 14)

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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)

An analysis of a hydrogen maser working with an unusual TE111 mode is presented. Different simulations have been carried out and are compared with preliminary results obtained for such a maser. In ... [more ▼]

An analysis of a hydrogen maser working with an unusual TE111 mode is presented. Different simulations have been carried out and are compared with preliminary results obtained for such a maser. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design hydrogen masers with significant reduced dimensions which represents a huge benefit for space applications and in particular for the global positioning system. [less ▲]

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See detailLight, alertness, cognition, and much more
Vandewalle, Gilles ULg

Scientific conference (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 detailRetrieval of ammonia from ground-based FTIR measurements and its use for validation of satellite observations by IASI
Dammers, E; Palm, M; Warneke, T et al

in Geophysical Research Abstracts (2015, April 13), 17

Atmospheric Ammonia (NH3) has a major impact on human health and ecosystem services and plays a major role in the formation of aerosols [Erisman et al.,2013; Paulot and Jacob 2014]. NH3 concentrations are ... [more ▼]

Atmospheric Ammonia (NH3) has a major impact on human health and ecosystem services and plays a major role in the formation of aerosols [Erisman et al.,2013; Paulot and Jacob 2014]. NH3 concentrations are highly variable in space and time with overall short lifetime due to deposition and aerosol formation. The global atmospheric budget of nitrogen and in turn NH3 is still uncertain which asks for more ground-based and satellite observations around the world. Recent papers have described the possibility to measure NH3 with satellite infrared sounders which open up the way for calculations of global and regional nitrogen budgets [Clarisse et al 2009,Van Damme et al 2014a]. Validation of the satellite observations is essential to determine the uncertainty in the signal and its potential use. So far available surface layer observations of atmospheric NH3 concentrations have been used for comparisons with total columns retrieved from satellite observations [Van Damme 2014b]. We developed a retrieval for NH3 column density concentrations (molecules NH3/cm2) by fitting a set of spectral windows to ground-based solar absorption Fourier transform infrared (FTIR) measurements with the spectral fitting program SFIT4 [Hase et al., 2004]. The retrieval is then applied to FTIR measurements from a set of spectrometer sites from the Network for detection of Atmospheric Composition Change (NDACC) to retrieve NH3 columns for the sites located in Bremen, Germany; Lauder, New Zealand; Jungfraujoch, Switzerland; and the island of Reunion, France. Using eight years (2005-2013) of retrieved NH3 columns clear seasonal cycles are observed for each of the stations. Maximum concentrations can be related to NH3 emission sources, specific for the regions. A comparison between the retrieved NH3 columns and observations from the recent IASI- NH3 product [Van Damme et al, 2014a] using strict spatial and temporal criteria for the selection of observations showed a good correlation (R=0.82; slope=0.63). The IASI- NH3 columns for the Bremen and Lauder area show similar temporal cycles when compared to the FTIR observations. [less ▲]

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See detailRecent increase of ethane detected in the remote atmosphere of the Northern Hemisphere
Franco, Bruno ULg; Bader, Whitney ULg; Bovy, Benoît ULg et al

Conference (2015, April 13)

Ethane (C2H6) has a large impact on tropospheric composition and air quality because of its involvement in the global VOC (volatile organic compound) – HOx – NOx chemistry responsible for generating and ... [more ▼]

Ethane (C2H6) has a large impact on tropospheric composition and air quality because of its involvement in the global VOC (volatile organic compound) – HOx – NOx chemistry responsible for generating and destroying tropospheric ozone. By acting as a major sink for tropospheric OH radicals, the abundance of C2H6 influences the atmospheric content of carbon monoxide and impacts the lifetime of methane. Moreover, it is an important source of PAN, a thermally unstable reservoir for NOx radicals. On a global scale, the main sources of C2H6 are leakage from the production, transport of natural gas loss, biofuel consumption and biomass burning, mainly located in the Northern Hemisphere. Due to its relatively long lifetime of approximately two months, C2H6 is a sensitive indicator of tropospheric pollution and transport. Using an optimized retrieval strategy (see Franco et al., 2014), we present here a 20-year long-term time series of C2H6 column abundance retrieved from ground-based Fourier Transform InfraRed (FTIR) solar spectra recorded from 1994 onwards at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5° N, 3580 m a.s.l.), part of the Network for the Detection of Atmospheric Composition Change (NDACC, see http://www.ndacc.org). After a regular 1994 – 2008 decrease of the C2H6 amounts, which is very consistent with prior major studies (e.g., Aydin et al., 2011; Simpson et al., 2012) and our understanding of global C2H6 emissions, trend analysis using a bootstrap resampling tool reveals a C2H6 upturn and a statistically-significant sharp burden increase from 2009 onwards (Franco et al., 2014). We hypothesize that this observed recent increase in C2H6 could affect the whole Northern Hemisphere and may be related to the recent massive growth in the exploitation of shale gas and tight oil reservoirs. This hypothesis is supported by measurements derived from solar occultation observations performed since 2004 by the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) instrument and at other NDACC sites, namely Toronto (44° N) and Thule (77° N). Indeed, the recent rates of changes characterizing these data sets are consistent in magnitude and sign with the one derived from the FTIR measurements at Jungfraujoch. In contrast, the ethane time series form Lauder (45° S) shows a monotonic decrease over the last two decades. Investigating both the cause and impact on air quality of the C2H6 upturn should be a high priority for the atmospheric chemistry community. [less ▲]

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See detailHalogenated source gases measured by FTIR at the Jungfraujoch station: updated trends and new target species
Mahieu, Emmanuel ULg; Bader, Whitney ULg; Bovy, Benoît ULg et al

in Geophysical Research Abstracts (2015, April 13), 17

In this contribution, we present decadal time series of halogenated source gases monitored at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl) with Fourier Transform Infared (FTIR ... [more ▼]

In this contribution, we present decadal time series of halogenated source gases monitored at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl) with Fourier Transform Infared (FTIR) spectrometers, within the framework of the Network for the Detection of Atmospheric Composition Change. Total column trends presented in previous studies for CFC-11, -12 and HCFC-22, CCl4, HCFC-142b, CF4 and SF6 will be updated using the latest available Jungfraujoch solar observations. Investigations dealing with the definition of approaches to retrieve additional halogenated source gases from FTIR spectra will also be evoked. Our trend results will be critically discussed and compared with measurements performed in the northern hemisphere by the in situ networks. [less ▲]

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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 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.).

Detailed reference viewed: 8 (1 ULg)
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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

Detailed reference viewed: 18 (2 ULg)
See detailLecteurs truqués : sur la fabrique médiatique du lectorat au XIXe siècle
Stienon, Valérie ULg

Scientific conference (2015, April 10)

Les voix du lecteur en journal semblent autant fabriquées que relayées. Faux profils, rubriques convenues, individualisation artificielle d’une catégorie de destinataires, confusion entre les récepteurs ... [more ▼]

Les voix du lecteur en journal semblent autant fabriquées que relayées. Faux profils, rubriques convenues, individualisation artificielle d’une catégorie de destinataires, confusion entre les récepteurs et l’équipe de rédaction : ce sont là des cas fréquents. C’est à ces non-coïncidences entre l’expression d’un discours présenté comme généré de l'extérieur du journal, par sa réception, et la ressaisie de ce discours dans le dispositif et la poétique du périodique de presse que sont consacrées les observations mises en évidence dans cette communication. [less ▲]

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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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