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See detailExperimental design to monitor the influence of crop residue management on the dynamics of soil water content
Chelin, Marie ULg; Parvin, Nargish ULg; Hiel, Marie-Pierre ULg et al

Poster (2015, April 15)

Choices related to crop residue management affecting soil structure determine spatio-temporal dynamics of water content and eventually crop yields. In this contribution, we discuss the experimental design ... [more ▼]

Choices related to crop residue management affecting soil structure determine spatio-temporal dynamics of water content and eventually crop yields. In this contribution, we discuss the experimental design we adopted to study the influence of three different agricultural management strategies (tillage and residue management) on the soil water dynamics under maize in a Cutanic Siltic Luvisol in Gembloux, Belgium. In order to limit soil disturbance, we opted for the use electrical resistivity tomography (ERT) and we use the bulk electrical conductivity as a proxy for soil moisture content. ERT is collected every week on a surface of two square meters corresponding to three rows of seven maize plants through surface stainless steel electrodes. Four additional sticks with stainless steel electrodes will be vertically inserted into the soil up to 1.20 m to get more detailed information near to the central maize row. In each of the monitoring plots, two time-domain reflectometry (TDR) probes will be installed for data validation. In order to calibrate the relationship between electrical resistivity and soil water content under highly variable field conditions (changes in soil structure, variable weather conditions, plant growth, fertilization), a trench will be dug, in which a set of four electrodes, one TDR probe and one temperature sensor will be placed at four different depths. In addition, two suction cups will be installed in each of the plots to quantify changes in ion composition and electrical conductivity of the soil solution at two different depths. Within the framework of the multidisciplinary research platform AgricultureIsLife, regular assessment of pore structure and crop developement will be conducted using X-ray images. Combining this wide range of data, we will be able to investigate and quantify the effect of simultaneously changing pore water conductivity, soil porosity, soil temperature and soil moisture on the effectiveness of time-lapse ER measurements as a proxy for soil moisture changes. [less ▲]

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See detailDUSP3 genetic deletion confers M2-like−macrophage-dependent tolerance to septic shock
Singh, Pratibha; Dejager, Lien; Amand, Mathieu ULg et al

in Journal of Immunology (2015)

DUSP3 is a small dual-specificity protein phosphatase with an unknown physiological function. We report that DUSP3 is strongly expressed in human and mouse monocytes and macrophages and that its ... [more ▼]

DUSP3 is a small dual-specificity protein phosphatase with an unknown physiological function. We report that DUSP3 is strongly expressed in human and mouse monocytes and macrophages and that its deficiency in mice promotes tolerance to lipopolysaccharide (LPS)-induced endotoxin shock and to polymicrobial septic shock following cecal ligation and puncture. By using adoptive transfer experiments, we demonstrate that resistance to endotoxin is macrophage-dependent and transferable and that this protection is associated with a striking increase of M2-like macrophages in DUSP3-/- mice in both the LPS and cecal ligation and puncture models. We show that the altered response of DUSP3-/- mice to sepsis is reflected in decreased TNF production and impaired ERK1/2 activation. Our results demonstrate that DUSP3 plays a key and non-redundant role as a regulator of innate immune responses by mechanisms involving the control of ERK1/2 activation, TNF secretion and macrophage polarization. [less ▲]

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

Poster (2015, April 14)

NIR Hyperspectral Imaging coupled with SVM chemometric tool is proposed as an alternative method to the tedious and time-consuming hand sorting step needed before root quantification using the soil coring ... [more ▼]

NIR Hyperspectral Imaging coupled with SVM chemometric tool is proposed as an alternative method to the tedious and time-consuming hand sorting step needed before root quantification using the soil coring method. This method was applied to quantify roots under a winter wheat crop. [less ▲]

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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 detailFuture projections of the Greenland ice sheet mass balance using the regional climate MAR model coupled with the GRISLI ice sheet model
Wyard, Coraline ULg; Fettweis, Xavier ULg; Ritz, Catherine

Poster (2015, April 14)

During the two last decades, the Greenland ice sheet (GrIS) contribution to the global mean sea level rise has significantly increased. But, difficulties remain to assess GrIS future contribution because ... [more ▼]

During the two last decades, the Greenland ice sheet (GrIS) contribution to the global mean sea level rise has significantly increased. But, difficulties remain to assess GrIS future contribution because of large uncertainties linked to the feedback between the surface mass balance (SMB) and GrIS topography changes. The regional climate MAR model has been coupled with the GRISLI ice sheet model, in order to account of this feedback in the future projections. The aim of this study is to assess the pertinence of the MAR-GRISLI coupling which requires long computation time. In order to identify GRISLI sensitivity to MAR forcing, GRISLI has been forced with various non-coupled (i.e. using a fixed topography), coupled and modified non-coupled MAR outputs. To adapt the non-coupled MAR outputs to the GRISLI topography changes, we use an interpolation technique based on SMB vs elevation vertical gradient. These experiences evaluate the performances/limits of this interpolation technique used to avoid a RCM-ice sheet model coupling. [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 detailOptical Study of a Spectrum Splitting Solar Concentrator based on a Combination of a Diffraction Grating and a Fresnel Lens
Michel, Céline ULg; Loicq, Jerôme ULg; Thibert, Tanguy ULg et al

Poster (2015, April 14)

This poster presents recent improvements of our new solar concentrator design for space application. The concentrator is based on a combination of a diffraction grating (blazed or lamellar) coupled with a ... [more ▼]

This poster presents recent improvements of our new solar concentrator design for space application. The concentrator is based on a combination of a diffraction grating (blazed or lamellar) coupled with a Fresnel lens. Thanks to this diffractive/refractive combination, this optical element splits spatially and spectrally the light and focus approximately respectively visible light and IR light onto electrically independent specific cells. It avoid the use of MJs cells and then also their limitations like current matching and lattice matching conditions, leading theoretically to a more tolerant system. The concept is reminded, with recent optimizations, ideal and more realistic results, and the description of an experimental realization highlighting the feasibility of the concept, and the closeness of theoretical and experimental results. [less ▲]

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See detailDiscrete Modeling : Thermidynamics Based on Shannon Entropy and Discrete States of Molecules
Pfleger, Martin; Wallek, Thomas; Pfennig, Andreas ULg

in Industrial and Engineering Chemistry (2015), 54

Detailed reference viewed: 23 (15 ULg)
See detailLIPOSOME CONTAINING ESTETROL FOR THE TREATMENT OF ISCHEMIA DISEASES IN PREMATURE BABIES
Palazzo, Claudio ULg; Karim, Reatul ULg; Mawet, Mawet et al

Poster (2015, April 14)

Detailed reference viewed: 24 (4 ULg)
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See detailA 500-year seasonally resolved δ 18 O and δ 13 C, layer thickness and calcite aspect record from a speleothem deposited in the Han-sur-Lesse cave, Belgium
Van Rampelbergh, M.; Verheyden, S.; Allan, Mohammed ULg et al

in Climate of the Past (2015), 11

Speleothem δ18O and δ13C signals enable climate reconstructions at high resolution. However, scarce decadal and seasonally resolved speleothem records are often diffi- cult to interpret in terms of climate ... [more ▼]

Speleothem δ18O and δ13C signals enable climate reconstructions at high resolution. However, scarce decadal and seasonally resolved speleothem records are often diffi- cult to interpret in terms of climate due to the multitude of factors that affect the proxy signals. In this paper, a fast- growing (up to 2 mm yr−1) seasonally laminated speleothem from the Han-sur-Lesse cave (Belgium) is analyzed for its δ18O and δ13C values, layer thickness and changes in cal- cite aspect. The studied record covers the period between AD 2001 and 1479 as indicated by layer counting and con- firmed by 20 U / Th ages. The Proserpine proxies are sea- sonally biased and document drier (and colder) winters on multidecadal scales. Higher δ13C signals reflect increased prior calcite precipitation (PCP) and lower soil activity dur- ing drier (and colder) winters. Thinner layers and darker calcite relate to slower growth and exist during drier (and colder) winter periods. Exceptionally dry (and cold) winter periods occur from 1565 to 1610, at 1730, from 1770 to 1800, from 1810 to 1860, and from 1880 to 1895 and correspond to exceptionally cold periods in historical and instrumental records as well as European winter temperature reconstruc- tions. More relative climate variations, during which the four measured proxies vary independently and display lower am- plitude variations, occur between 1479 and 1565, between 1610 and 1730, and between 1730 and 1770. The winters during the first and last periods are interpreted as relatively wetter (and warmer) and correspond to warmer periods in historical data and in winter temperature reconstructions in Europe. The winters in the period between 1610 and 1730 are interpreted as relatively drier (and cooler) and correspond to generally colder conditions in Europe. Interpretation of the seasonal variations in δ18O and δ13C signals differs from that on a decadal and multidecadal scale. Seasonal δ18O variations reflect cave air temperature variations and suggest a 2.5◦C seasonality in cave air temperature during the two relatively wetter (and warmer) winter periods (1479–1565 and 1730–1770), which corresponds to the cave air temper- ature seasonality observed today. Between 1610 and 1730, the δ18O values suggest a 1.5◦C seasonality in cave air tem- perature, indicating colder summer temperatures during this drier (and cooler) interval. The δ13C seasonality is driven by PCP and suggests generally lower PCP seasonal effects be- tween 1479 and 1810 compared to today. A short interval of increased PCP seasonality occurs between 1600 and 1660, and reflects increased PCP in summer due to decreased win- ter recharge. [less ▲]

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

Scientific conference (2015, April 13)

Detailed reference viewed: 13 (0 ULg)
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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 ▲]

Detailed reference viewed: 36 (9 ULg)