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See detailMedium and High Resolution Vacuum UV Photoabsorption Spectroscopy of Methyl Iodide (CH3I) and its deuterated isotopomers CD3I and CH2DI. A Rydberg series Analysis.
Locht, Robert ULg; Leyh, Bernard ULg; Jochims, H.-W. et al

in Chemical Physics (2009), 365(3), 109-128

The vacuum UV photoabsorption spectrum of CH3I has been investigated between 5 and 20 eV. Numerous vibronic transitions are observed. In the high 10-20 eV photon energy range weak to very weak diffuse ... [more ▼]

The vacuum UV photoabsorption spectrum of CH3I has been investigated between 5 and 20 eV. Numerous vibronic transitions are observed. In the high 10-20 eV photon energy range weak to very weak diffuse bands are observed and ascribed to electronic transitions from 3a1, 1e and 2a1 to Rydberg orbitals. In the 6-10.5 eV photon energy range more than 200 sharp and strong to weak lines have been observed. Several photon energy ranges were explored under high resolution conditions allowing us to observe many series up to high values of the principal quantum number n. They are assigned to vibrationless Rydberg transitions and classified into two groups converging to the two components of the spin-orbit split 2E state of CH3I+. These two groups consist of six different Rydberg series, i.e., nsa1, npa1, npe, nda1, nde and nf. A very close correlation has been established between the term values of the Rydberg states in CH3I and in Xe for ns, np, nd and nf Rydberg transitions. For the first time, the same measurements have been performed and the interpretation has been proposed for the photoabsorption spectrum of CH2DI and CD3I in the 6-10.5 eV photon energy range. For these two species, ionization energies are deduced: for the 2E3/2 and 2E1/2 states of CH2DI, these are IEad=9.544 eV and IEad=10.168 eV respectively and the corresponding energies are 9.552 eV and 10.173 eV in CD3I. [less ▲]

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See detailA modeling system handling the wide range of time scales involved in sediment transport processes
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Proc. 6th International SedNet conference (2009)

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See detailUse of cDNA-AFLP to study the defence-related gene expression in bananas (Musa spp.), inoculated with Colletotrichum musae responsible of crown rot
Lassois, Ludivine ULg; de Lapeyre de Bellaire, Luc; Jijakli, Haissam ULg

Conference (2009)

Crown rot disease of bananas is widespread in producing countries and is considered as the most important post-harvest disease of exported bananas. Variations of susceptibility to the disease have been ... [more ▼]

Crown rot disease of bananas is widespread in producing countries and is considered as the most important post-harvest disease of exported bananas. Variations of susceptibility to the disease have been noted between bananas but the origins still unknown. The biological responses of the fruit, including physiological change and disease susceptibility are controlled and regulated by gene expression. One way to understanding the reactions involved in variation of banana susceptibility to the disease in relation to their physiological state, is to study the expression of genes involved in these processes. To this purpose, crown sample previously inoculated with C. musae and showing 2 levels of susceptibility (very high and very low) were collected to be compared. Crown sample of each susceptibility level was collected at two different maturity stages: at harvest and 13 days after harvest (3 days after ripening). Collected crowns were immediately freeze-dried, an original method to conserve gene expression. cDNA-AFLP was applied on these 4 cell populations in order to highlight the differential transcription of genes whose function is "a priori" unknown. The cDNA-AFLP result was confirmed using quantitative real-time reverse transcription PCR. Various defence-related genes were identified and will be presented. [less ▲]

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See detailAgronomical and molecular factors influencing bananas (Musa acuminata, AAA, cv ‘Grande-Naine’) susceptibility to crown rot disease
Lassois, Ludivine ULg

Doctoral thesis (2009)

Crown rot affects export bananas in all producing countries and is considered to be one of the main export banana post-harvest disease. Variations are observed in the expression of crown rot symptoms. An ... [more ▼]

Crown rot affects export bananas in all producing countries and is considered to be one of the main export banana post-harvest disease. Variations are observed in the expression of crown rot symptoms. An original approach of the disease is proposed and consists on presenting the fruit quality potential at harvest as a key factor in crown rot development. This potential develops during growth of bananas in the field and depends on a physiological and a parasitical component. The physiological component refers here to the level of fruit susceptibility to crown rot and reflects the physiological state of the fruit. The aim of this study was to clarify the role of the fruit physiological component at harvest in the post-harvest crown rot development. It appears that the fruit physiological component at harvest greatly influence the postharvest disease development and thus the fruit susceptibility. Seasonal variations in disease severity were shown in two production area and are related to a variation of the fruit physiological component. In Guadeloupian conditions, the internal necrotic surface of the crown was nearly multiplied by 4 during 11 successive weeks. Two pre-harvest factors that could influence the fruit physiological component by modifying their susceptibility to crown rot, were identified: (i) hand position on the bunch and (ii) source-sink ratio of the banana plant (hand considered as sink and leaves as source). It was shown that within a bunch, there is a gradient of susceptibility to crown rot (r= -0.95), the hands initiated first (the upper ones) being more susceptible than those initiated last (the lower ones). These results also confirmed that source-sink ratio changes have a significant effect on fruit morphology and demonstrated that there is also an effect on fruit susceptibility to crown rot disease. When the sink is decreased by artificial removal of many hands, the level of fruit susceptibility to crown rot decreases. However, the molecular mechanisms underlying these quantitative host-pathogen relationships were still unknown. A study was designed to compare gene expression, by cDNA-AFLP, between crowns of bananas showing a high susceptibility (S+) and crowns of bananas showing a low susceptibility (S-) to Colletotrichum musae responsible for crown rot disease. This comparison was performed at two situation time: (i) between crowns (S+ and S-) collected one hour before infection and (ii) between crowns (S+ and S-) collected 13 days after infection. Genes implied in signaling pathway and proteolytic machinery were identified. It also appears that a cellulose synthase, a CAF1 gene, 2 glycolipid transfer protein and a dopamine-β-monooxygenase were differently expressed between bananas showing different levels of susceptibility. This is the first study of the characterization of the banana physiological component at harvest which influences the crown rot post-harvest disease development. In addition, to our knowledge, this work is the first to address both pre- and post-infection gene expression with the same host-pathogen combination and different susceptibility levels. [less ▲]

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See detailAdditional parameters for the morphometry of angiogenesis and lymphangiogenesis in corneal flatmounts
Blacher, Silvia ULg; Detry, Benoît ULg; Bruyere, Françoise et al

in Experimental Eye Research (2009), 89(2), 274-276

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See detailDam Break Flow Modelling and Geographical Distribution of the Roughness Coefficient
Paulus, Raphaël ULg; Ernst, Julien ULg; Dewals, Benjamin ULg et al

in Proc. 33rd IAHR Congress: Water Engineering for a Sustainable Environment (pp. 2429-2436) (2009)

Dam break flow modelling is a major field of research. In order to enable risk analysis in the downstream valleys of dams, 2D numerical simulations are of prime interest. These are based on the ... [more ▼]

Dam break flow modelling is a major field of research. In order to enable risk analysis in the downstream valleys of dams, 2D numerical simulations are of prime interest. These are based on the conservative set of shallow water equations. Beyond their numerical implementation, the challenge of the computation relies on the ability to handle very huge sets of high-precision data, in order to get the highest possible accuracy, whereas the computational time must remain realistic for simulations carried out on real valleys topography. In this paper, a simulation on about 2 500 000 cells is presented. Particularly, the results are compared and discussed regarding especially the exploitation of landuse data for the roughness. Beyond the examples of validation, the relevance of the developed methodology appears to be essential in the framework of risk analysis. [less ▲]

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See detailMilk production of imported heifers and Tunisian-born Holstein cows
Rekik, Boulbaba; Bouraoui, Rachid; Ben gara, Abderrahmen et al

in American-Eurasian Journal of Agronomy (2009), 1(3), 36-42

Test day (TD) records of milk, fat and protein yields and somatic cell scores (SCS) were studied in Holstein cows in Tunisia. There were 43114, 32923 and 24633 lactation records collected on first, second ... [more ▼]

Test day (TD) records of milk, fat and protein yields and somatic cell scores (SCS) were studied in Holstein cows in Tunisia. There were 43114, 32923 and 24633 lactation records collected on first, second and third parity cows between 1992 and 2004 in 182 herds. Records were of cows born in Tunisia (22000 cows) and those imported from Europe (10830 cows) and North America (850 cows). Variation of total days in milk (DIM) per lactation was studied in function of the herd, calving year x calving season interaction and the origin of the cow. Test-day records were analyzed using a linear model that included calving year x calving season and herd x test-day date interactions, calving season, calving year and origin of the cow. The effective length of lactation was affected by all factors included in the model (p< 0.0001) in all lactations. Test- day milk, protein and fat yields and TD SCS varied (p< 0.01) with management and climatic factors (calving year x calving season and herd x test-day date interactions and year and season of calving). A cow produced 18.8 kg, 0.61 kg and 0.58 kg of milk, fat and protein yields on a daily basis in all lactations, respectively. Average SCS was 2.8 in the three lactations. The origin of the cow was an important (p < 0.05) source of variation for DIM, yields and SCS in all lactations except for first lactation cell scores (p>0.05). Cows born in Tunisia seemed to perform better than imported cows in the first lactation while imported cows showed clearly better performances in later lactations. North American cows produced the highest yields and had the lowest SCS among all cows in the second and third lactations. Imported high producing cows seemed able to adjust to Tunisian management conditions following their first lactation. [less ▲]

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See detailLarge scale experimental study of piano key weirs
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Proc. 33rd IAHR Congress: Water Engineering for a Sustainable Environment (2009)

Piano Key Weirs (PKW) are a new type of weir, showing very good flood release capacities as well as strong economic and structural benefits. However, lacks of understanding persist about the flow ... [more ▼]

Piano Key Weirs (PKW) are a new type of weir, showing very good flood release capacities as well as strong economic and structural benefits. However, lacks of understanding persist about the flow conditions on such structures. With the goal to fill some of these lacks, a combined experimental and numerical study has been undertaken at the Laboratory of Structures Hydraulics of the University of Liege. This paper presents the goals and the scientific strategy of this research. The first results of experiments being carried out on a large physical model of PKW are also depicted. These experiments lead to characterization of the flow behavior for low heads and enable to highlight the influence of the crest thickness and the outlet slope on the release capacity. [less ▲]

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See detailDéveloppement durable des races bovines locales menacées
Bay, Elodie

Article for general public (2009)

Le projet EURECA a pour but d'assister la conservation, le développement et l'utilisation des races bovines locales, et ce en se basant sur l'étude de races locales dans 10 pays européens. Ce projet (d ... [more ▼]

Le projet EURECA a pour but d'assister la conservation, le développement et l'utilisation des races bovines locales, et ce en se basant sur l'étude de races locales dans 10 pays européens. Ce projet (d'une durée totale de 3 ans) est coordonné au niveau belge par le Faculté des Sciences Agronomiques de Gembloux. La première phase du projet, présentée dans cet article, a consisté à interroger des éleveurs et des parties prenantes à l'aide d'un formulaire standard, afin de comprendre comment s'intègre les races locales au niveau des différents intervenants. L'étude a porté sur la Pie Rouge Mixte (PRm) et la Blanc Bleu Mixte (BBm). [less ▲]

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See detailQuelle approche pour évaluer les résultats d'un projet d’enseignement à distance?
Dujardin, Jean-Marie ULg; Maron, Séverine ULg

in Distances et Savoirs (2009), 7(1),

Since 2002 the so called “Campus Virtuel en Gestion” has developed on line courses in the field of management. The partners of the project wanted to know more about its results, from both a pedagogical ... [more ▼]

Since 2002 the so called “Campus Virtuel en Gestion” has developed on line courses in the field of management. The partners of the project wanted to know more about its results, from both a pedagogical and an economic point of view. The questions we address here are the following: – how to assess this project on both its economic and pedagogical effects? – how to carry out such an assessment? – what are the advantages and the limits of this approach? The difficulties of application, the interests, the limits of the methodology will be explained. [less ▲]

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See detailBottom friction formulations for free surface flow modeling
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in 8th NCTAM Congress (2009)

Bottom friction modeling is an important step in river flows computation with 1D or 2D solvers. It is usually performed using empirical laws established for uniform flow conditions or a modern approach ... [more ▼]

Bottom friction modeling is an important step in river flows computation with 1D or 2D solvers. It is usually performed using empirical laws established for uniform flow conditions or a modern approach based on turbulence analysis. Following the definition of the flow validity field of the main friction laws proposed in the iterature, an original continuous formulation has been developed. It is suited to model river flows with a high variability of properties (water depth, discharge, roughness…). The efficiency of this new formulation, theoretically established and numerically adjusted, is demonstrated through various practical applications. [less ▲]

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See detailMembrane-Type 4 Matrix Metalloproteinase (MT4-MMP) induces lung metastasis by alteration of primary breast tumor vascular architecture
Chabottaux, Vincent; Ricaud, Stéphanie; Host, Lorin et al

in Journal of Cellular & Molecular Medicine (2009)

The present study aims at investigating the mechanism by which MT4-MMP, a membrane-anchored MMP expressed by human breast tumor cells promotes the metastatic dissemination into lung. We applied ... [more ▼]

The present study aims at investigating the mechanism by which MT4-MMP, a membrane-anchored MMP expressed by human breast tumor cells promotes the metastatic dissemination into lung. We applied experimental (intravenous) and spontaneous (subcutaneous) models of lung metastasis using human breast adenocarcinoma MDA-MB-231 cells overexpressing or not MT4-MMP. We found that MT4-MMP does not affect lymph node colonization nor extravasation of cells from the bloodstream, but increases the intravasation step leading to metastasis. Ultrastructural and fluorescent microscopic observations coupled with automatic computer-assisted quantifications revealed that MT4-MMP expression induces blood vessel enlargement and promotes the detachment of mural cells from the vascular tree, thus causing an increased tumor vascular leak. On this basis, we propose that MT4-MMP promotes lung metastasis by disturbing the tumor vessel integrity and thereby facilitating tumor cell intravasation. [less ▲]

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See detailConcurrence difficile
Petit, Nicolas ULg

Article for general public (2009)

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See detailDam-break flow numerical modeling considering structural impacts on buildings
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Proc. 33rd IAHR Congress: Water Engineering for a Sustainable Environment (2009)

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See detailTrou Al’Wesse (Commune de Modave, province de Liège): la séquence pléistocène
Miller, Rebecca ULg; Otte, Marcel ULg; Stewart, John

in Chronique de l'Archéologie Wallonne (2009), 16

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See detailThe post-harvest quality of bananas is determined by pre-harvest factors
de Lapeyre de Bellaire, Luc; Chillet, Marc; Lassois, Ludivine ULg et al

Poster (2009)

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