Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailGrotesques, concrétions et paysages
Havelange, Carl ULg; Christiaens, Alexandre

Book published by Les Brasseurs/art contemporain (2007)

Detailed reference viewed: 9 (1 ULg)
Full Text
See detailLa grotte d'Öküzini: chronologie et mode de fonctionnement d'un remplissage (analyse radiométrique, rythme sédimentaire et cycles climatiques)
López Bayón, Ignacio; Léotard, Jean-Marc; Kartal, Metin et al

in Yalçinkaya, Isin; Otte, Marcel; Kozlowski, Janusz (Eds.) et al La grotte d'Öküzini. Évolution du Paléolithique final du sud-ouest de l'Anatolie (2002)

Detailed reference viewed: 22 (0 ULg)
Full Text
See detailLa grotte de Remouchamps
Ek, Camille ULg; Dewez, Michel; Denoël, René et al

Book published by Lesire (1972)

The first inhabitants of the cave. Explorations history. Geology. Cave genesis. Speleothems genesis. The cave climate. Fauna. The swallowhole Dale.

Detailed reference viewed: 35 (8 ULg)
Full Text
See detailLa grotte de Spy (Jemeppe-sur-Sambre ; prov. Namur)
Semal, Patrick; Jungels, Cécile; Di Modica, Kevin et al

in Toussaint, Michel; Di Modica, Kevin; Pirson, Stéphane (Eds.) Le Paléolithique moyen en Belgique. Mélanges Marguerite Ulrix-Closset (2011)

Detailed reference viewed: 29 (3 ULg)
Full Text
See detailLa Grotte du Bois Laiterie, du Magdalénien au Mésolithique: différences comportementales
López Bayón, Ignacio; Straus, Lawrence; Otte, Marcel ULg et al

in Notae Praehistoricae (1996), 16

Detailed reference viewed: 59 (3 ULg)
Full Text
See detailLa Grotte et l'Abîme de Comblain-au-Pont
Ek, Camille ULg; Godissart, Jean

Book published by Découverte de Comblain-au-Pont et environs, ASBL (2007)

Summary: Historical review; Geology; Cave genesis; Climate; Fauna; Paleontology

Detailed reference viewed: 96 (16 ULg)
Full Text
Peer Reviewed
See detailLes grottes d'Azé (Saône-et-Loire, France): de la roche altérée aux sédiments
Barriquand, Lionel; Barriquand, Johan; Baele, Jean-Marc et al

in Karstologia (2012), 59

Detailed reference viewed: 13 (1 ULg)
Full Text
See detailGrottes et rivières des régions calcaires
Ek, Camille ULg

in Demoulin, Alain (Ed.) L'Ardenne, Essai de Géographie physique. Hommage à A. Pissart (1995)

Location of soluble rocks and karstic areas. Morphology of closed depressions. Valleys of limestone regions; dry valleys; blind valleys. Caves. Present-day processes.

Detailed reference viewed: 88 (22 ULg)
Full Text
Peer Reviewed
See detailGround and Excited State Dissociation Dynamics of Ionized 1,1-Difluoroethene
Gridelet, Evelyne; Dehareng, Dominique ULg; Locht, Robert ULg et al

in Journal of Physical Chemistry A (2005), 109(37), 8225-8235

The kinetic energy release distributions (KERDs) for the fluorine atom loss from the 1,1-difluoroethene cation have been recorded with two spectrometers in two different energy ranges. A first experiment ... [more ▼]

The kinetic energy release distributions (KERDs) for the fluorine atom loss from the 1,1-difluoroethene cation have been recorded with two spectrometers in two different energy ranges. A first experiment uses dissociative photoionization with the He(I) and Ne(I) resonance lines, providing the ions with a broad internal energy range, up to 7 eV above the dissociation threshold. The second experiment samples the metastable range, and the average ion internal energy is limited to about 0.2 eV above the threshold. In both energy domains, KERDs are found to be bimodal. Each component has been analyzed by the maximum entropy method. The narrow, low kinetic energy components display for both experiments the characteristics of a statistical, simple bond cleavage reaction: constraint equal to the square root of the fragment kinetic energy and ergodicity index higher than 90%. Furthermore, this component is satisfactorily accounted for in the metastable time scale by the orbiting transition state theory. Potential energy surfaces corresponding to the five lowest electronic states of the dissociating 1,1-C2H2F2+ ion have been investigated by ab initio calculations at various levels. The equilibrium geometry of these states, their dissociation energies, and their vibrational wavenumbers have been calculated, and a few conical intersections between these surfaces have been identified. It comes out that the ionic ground state (X) over tilde B-2(1) is adiabatically correlated with the lowest dissociation asymptote. Its potential energy curve increases in a monotonic way along the reaction coordinate, giving rise to the narrow KERD component. Two states embedded in the third photoelectron band ( (B) over tilde (2)A(1), at 15.95 eV and (C) over tilde B-2(2) at 16.17 eV) also correlate with the lowest asymptote at 14.24 eV. We suggest that their repulsive behavior along the reaction coordinate be responsible for the KERD high kinetic energy contribution. [less ▲]

Detailed reference viewed: 58 (19 ULg)
Full Text
Peer Reviewed
See detailGround beetle habitat templets and riverbank integrity
van Looy, K.; Vanacker, S.; Jochems, H. et al

in River Research & Applications (2005), 21(10), 1133-1146

The habitat templet approach was used in a scale-sensitive bioindicator assessment for the ecological integrity of riverbanks and for specific responses to river management. Ground beetle habitat templets ... [more ▼]

The habitat templet approach was used in a scale-sensitive bioindicator assessment for the ecological integrity of riverbanks and for specific responses to river management. Ground beetle habitat templets were derived from a catchment-scale sampling, integrating the overall variety of bank types. This coarse-filter analysis was integrated in the reach-scale fine-filtering approaches of community responses to habitat integrity and river management impacts. Higher species diversity was associated with the higher heterogeneity in bank habitats of the un-navigable river reaches. The abundant presence of habitat specialists in the riverbank zone allows a habitat integrity assessment based on the habitat templet indicator species. Significant responses were detected for channel morphology in the width-to-depth ratio and for hydrological regime in peak frequency and peak velocity, enabling the development of evaluation methods for the impact assessment of river management and flood protection strategies. Copyright © 2005 John Wiley & Sons, Ltd. [less ▲]

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailGround Night Nesting in Chimpanzees: New Insights from Central Chimpanzees (Pan troglodytes troglodytes) in South-East Cameroon
Tagg, Nikki; Willie, Jacob; Petre, Charles-Albert ULg et al

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013), 84

Detailed reference viewed: 9 (3 ULg)
Full Text
See detailGround water flow simulation in mining works: Application of the Hybrid Finite Element Mixing Cell method
Wildemeersch, Samuel ULg; Orban, Philippe ULg; Brouyère, Serge ULg et al

Conference (2009, April 22)

Hydrogeological models can greatly help simulating groundwater flow in the particular context of mining works. However, classical modeling techniques are not so suited in this context because the medium ... [more ▼]

Hydrogeological models can greatly help simulating groundwater flow in the particular context of mining works. However, classical modeling techniques are not so suited in this context because the medium is strongly disturbed by shafts and networks of galleries. Consequently, specific modeling techniques have been developed. Box model techniques require only few parameters but they calculate only mean water levels in exploited zones and do not consider interactions between exploited and unexploited zones. Conversely, physically-based and spatially-distributed techniques represent explicitly both exploited and unexploited zones and take into account interactions between them but they require a lot of parameters sometimes difficult to estimate. The Hybrid Finite Element Mixing Cell (HFEMC) method is a new modeling technique constituting a compromise between simple and complex techniques used in mining context. The principle of this method is to fully couple a representation of exploited zones by a group of mixing cells possibly interconnected by pipes and a representation of unexploited zones by classical finite elements. Interactions between mixing cells and finite elements of the mesh are taken into account through 3rd type (Fourier) internal boundary conditions. With this method, exploited zones are characterized by mean water levels while spatially-distributed hydraulic heads are calculated for the entire adjacent and overlaying unexploited zones. Additionally, thanks to the coupling between mixing cells and finite elements, water exchanges between exploited and unexploited zones are explicitly taken into account. The HFEMC method allows also simulating groundwater rebound following mine closure and associated phenomena such as water inrushes. Concepts and equations of the HFEMC method are presented and illustrated using test cases. First results of an application on an abandoned coalfield in the region of Liege (Belgium) are also proposed. [less ▲]

Detailed reference viewed: 113 (28 ULg)
Full Text
See detailGround-based and HST Direct Imaging of HLQs
Surdej, Jean ULg; Jaunsen, A. O.; Claeskens, Jean-François ULg et al

in Kochanek, C.; Hewitt, J. (Eds.) Astrophysical Applications of Gravitational Lensing (1996)

Detailed reference viewed: 18 (8 ULg)
See detailGround-based CO observations at the Jungfraujoch from 1997 till 2007: Comparison between FTIR and NDIR measurements
Dils, Bart; Demoulin, Philippe ULg; Mahieu, Emmanuel ULg et al

Poster (2009, January 26)

Here we will discuss CO measurements taken at the Swiss Alpine Jungfraujoch station (46.5º N, 8.0° E, 3580m a.s.l.) over the 1997-2007 time period. Results from two distinct techniques, namely Fourier ... [more ▼]

Here we will discuss CO measurements taken at the Swiss Alpine Jungfraujoch station (46.5º N, 8.0° E, 3580m a.s.l.) over the 1997-2007 time period. Results from two distinct techniques, namely Fourier Transform Infrared solar absorption spectrometry (FTIR), and the in situ Nondispersive Infrared technique (NDIR) have been compared. While the in situ NDIR measurements detect local CO concentrations at the site, the FTIR technique provides integrated measurements along the line-of-sight. Nevertheless, the pressure broadening of the spectral absorption lines recorded at high resolution enables retrieving information on the vertical distribution of CO, mainly in the troposphere, including its concentration near the surface. To provide enough information content the averaged vmr between 3.58 and 7 km is derived from the FTIR profile data. Both datasets show a significant negative trend over the time period. However, the NDIR dataset's negative trend is much stronger. Pettitt change point tests reveal that the NDIR-FTIR bias changes substantially from 1997 till 2004 after which the bias stabilizes. Possible causes for these observations will be critically discussed. [less ▲]

Detailed reference viewed: 52 (1 ULg)
Full Text
See detailGround-based CO observations at the Jungfraujoch: Comparison between FTIR and NDIR measurements
Dils, Bart; Mahieu, Emmanuel ULg; Demoulin, Philippe ULg et al

in Geophysical Research Abstracts (2008), 10

Measurements of CO have been performed at the Swiss Alpine Jungfraujoch station (46.5º N, 8.0° E, 3580m a.s.l.) on a regular basis since the mid-1980’s, using Fourier Transform Infrared solar absorption ... [more ▼]

Measurements of CO have been performed at the Swiss Alpine Jungfraujoch station (46.5º N, 8.0° E, 3580m a.s.l.) on a regular basis since the mid-1980’s, using Fourier Transform Infrared solar absorption spectrometry (FTIR), and since 1996 using an in situ Nondispersive Infrared technique (NDIR). While the in situ measurements detect local CO concentrations at the site, the FTIR technique provides integrated measurements along the line-of-sight. Nevertheless, the pressure broadening of the spectral absorption lines recorded at high resolution enables retrieving information on the vertical distribution of CO, mainly in the troposphere, including its concentration near the surface. Considering the inherent capabilities of the two independent measurement techniques, substantial differences between both data sets for surface level CO could potentially arise. Here we present a comparison of both data sets for the 1997 -2004 time period. Both data sets have been analysed by using successive Kolmogorov-Zurbenko filters. It appears that the long-term trend over the given time period is significantly different for both datasets. Possible causes for this difference will be critically discussed. [less ▲]

Detailed reference viewed: 40 (0 ULg)
Full Text
See detailThe Ground-based European Nulling Interferometry Experiment (DARWIN-GENIE)
Gondoin, P.; Absil, Olivier ULg; den Hartog, R. et al

in Fridlund, Malcolm; Henning, Thomas (Eds.) Towards Other Earths: DARWIN/TPF and the Search for Extrasolar Terrestrial Planets (2003, October 01)

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise ... [more ▼]

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise their atmospheres. Darwin is conceived as a space "nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. [less ▲]

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailGround-based follow-up in relation to Kepler asteroseismic investigation
Uytterhoeven, K.; Briquet, Maryline ULg; Bruntt, H. et al

in Astronomische Nachrichten (2010), 331

The Kepler space mission, successfully launched in March 2009, is providing continuous and high-precision photometry of thousands of stars simultaneously. The uninterrupted time-series of stars of all ... [more ▼]

The Kepler space mission, successfully launched in March 2009, is providing continuous and high-precision photometry of thousands of stars simultaneously. The uninterrupted time-series of stars of all known pulsation types are a precious source for asteroseismic studies. The Kepler data do not provide information on the physical parameters, such as T_eff, log g, metallicity, and v sin i, which are crucial for successful asteroseismic modelling. Additional ground-based time-series data are needed to characterize mode parameters in several types of pulsating stars. Therefore, ground-based multi-colour photometry and mid/high-resolution spectroscopy are needed to complement the space data. We present ground-based activities within KASC on selected asteroseismic Kepler targets of several pulsation types. Based on observations made with the Isaac Newton Telescope and William Herschel Telescope operated by the Isaac Newton Group, with the Nordic Optical Telescope, operated jointly by Denmark, Finland, Iceland, Norway, and Sweden, with the Italian Telescopio Nazionale Galileo (TNG) operated by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica), and with the Mercator telescope, operated by the Flemish Community, all on the island of La Palma at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (IAC). Based on observations made with the IAC-80 operated on the island of Tenerife by the IAC at the Spanish Observatorio del Teide. Also based on observations taken at the observatories of Sierra Nevada, San Pedro Mártir, Vienna, Xinglong, Apache Point, Lulin, Tautenburg, McDonald, Skinakas, Pic du Midi, Mauna Kea, Steward Observatory, Mt. Wilson, Białków Observatory of the Wrocław University, Piszkésteto Mountain Station, and Observatoire de Haute Provence. Based on spectra taken at the Loiano (INAF - OA Bologna), Serra La Nave (INAF - OA Catania) and Asiago (INAF - OA Padova) observatories. Also based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck-Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). We acknowledge with thanks the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this research. Funding for the Kepler mission is provided by NASA's Science Mission Directorate. We thank the entire Kepler team for the development and operations of this outstanding mission. [less ▲]

Detailed reference viewed: 12 (1 ULg)
Full Text
See detailGround-based FTIR measurements at Ile de La Réunion: Observations, error analysis and comparisons with satellite data.
Senten, Cindy; De Mazière, Martine; Hermans, Christian et al

in Geophysical Research Abstracts (2007), 9

Ground-based Fourier-transform infrared (FTIR) spectroscopy is a powerful remote sensing technique to obtain information on the total column abundances and on the vertical distribution of various ... [more ▼]

Ground-based Fourier-transform infrared (FTIR) spectroscopy is a powerful remote sensing technique to obtain information on the total column abundances and on the vertical distribution of various constituents in the atmosphere. Many of these species are essential for the investigation of important atmospheric phenomena, such as the overall greenhouse effect or the stratospheric ozone decrease and recovery. In the frame of the Network for the Detection of Atmospheric Composition Change (NDACC), such observations have been made since many years at several measurement stations for the worldwide long-term monitoring of the atmospheric composition. In this work, we present the results from two short-term FTIR measurement campaigns in 2002 and 2004 at the Ile de La Réunion (21°S, 55°E), a complementary NDACC site in the subtropics, in the Indian Ocean. All spectra were recorded in solar absorption mode. The results discussed here concern the direct greenhouse gases methane (CH4), nitrous oxide (N2O) and ozone (O3), and the indirect greenhouse gases carbon monoxide (CO) and ethane (C2H6), as well as hydrogen cyanide (HCN) and stratospheric hydrogen chloride (HCl), hydrogen fluoride (HF) and nitric acid (HNO3). For the latter species (HCN, HCl, HF and HNO3), we show time series of total column amounts from the surface up to 60 km. For CO, CH4, N2O and O3, it is possible to derive additionally independent information on a few partial columns; these time series are discussed as well. A complete error budget of the retrieval products is given. Temporary mutually correlated enhancements of CO, C2H6and HCN have been observed. They have been traced back to biomass burning events in southern Africa and Madagascar using the FLEXPART model. Comparisons of our retrievals with correlative data from satellite experiments, such as ACE and MOPITT, and with available ozone soundings, show generally good agreements between the different data sets. [less ▲]

Detailed reference viewed: 55 (3 ULg)
Full Text
See detailGround-based FTIR Measurements from a Series of European sites during the Winter of 1995/96 and a Comparison with a 3D Chemical Transport Model: Evidence of Chlorine Activation and Ozone depletion
Paton Walsh, C.; Bell, W.; Blumenstock, T. et al

in Harris, N. R. P.; Kilbane-Dawe, I.; Amanatidis, G.T. (Eds.) Polar stratospheric ozone 1997 (1998)

Fourier transform infra-red (FTIR) measurements of stratospheric trace species have been made at a network of five ground-based sites from 79°N to 47°N during the Northern hemisphere winter of 1995/1996 ... [more ▼]

Fourier transform infra-red (FTIR) measurements of stratospheric trace species have been made at a network of five ground-based sites from 79°N to 47°N during the Northern hemisphere winter of 1995/1996. This winter was extremely cold with temperatures below the threshold for type 1 polar stratospheric cloud (PSC) formation from mid December 1995 until early March 1996 when there was a rapid warming of the stratosphere. Over 25 days experienced temperatures low enough for ice cloud (PSC type 2) formation. Vertical columns values for HCl, ClONO2, HF and HNO3 have been derived from FTIR measurements at the following sites: Ny Alesund, Spitzbergen (79°N, 12°E); Kiruna, Sweden (67°N, 21°E); Harestua, Norway (60°N, 11°E); London, England (51°N, 0°E) and the Jungfraujoch, Switzerland (48°N, 8°E), with measurements of other stratospheric trace gases, including O3 and ClO available from some of the sites. All of these sites are equipped with high resolution Bruker 120HR or 120M spectrometers, recording atmospheric spectra in the mid infrared using the Sun as a source. These measurements have been used to provide both evidence of substantial activation within large areas of the polar vortex and a subsequent O3 depletion. The measurements suggest a well mixed central vortex area surrounded by a vortex edge that may be highly variable in composition. The measurements also provide evidence of substantial mixing of activated air from the edge of the polar vortex into middle latitudes. Comparison with the SLIMCAT 3D chemical transport model highlights the underestimation of ClONO2 concentrations in the model, with subsequent implications for underestimating O3 loss. [less ▲]

Detailed reference viewed: 10 (1 ULg)