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See detailCharacterization of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) overwintering sites
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Haubruge, Eric ULg et al

Poster (2012, February 10)

The invasive multicoloured Asian ladybird, Harmonia axyridis (Pallas), forms large aggregations inside dwellings to overwinter. In order to highlight the specific features of infested houses, we ... [more ▼]

The invasive multicoloured Asian ladybird, Harmonia axyridis (Pallas), forms large aggregations inside dwellings to overwinter. In order to highlight the specific features of infested houses, we investigated a large number of overwintering sites in Wallonia between 2007 and 2011. These sites were characterized through a survey sent to homeowners confronted to invasion problems. The results indicate that H. axyridis preferentially selects isolated brick houses with red or white fronts to take shelter. Aggregations are mostly located at the first floor, essentially inside south or west oriented rooms. Furthermore, ladybirds generally gathered into wooden windows frames facing south or west, and to a lesser extent, in the upper corners of walls presenting the same orientation. [less ▲]

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See detailCharacterization of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) overwintering sites
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Francis, Frédéric ULg et al

Poster (2012, August)

Originally introduced as a biological control agent, the multicoloured Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become an invasive pest throughout Europe and North ... [more ▼]

Originally introduced as a biological control agent, the multicoloured Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become an invasive pest throughout Europe and North America in the last few years. Although its effectiveness to control aphid and coccid populations was impressive, some negative impacts appeared rapidly, notably on human health. Indeed, to protect themselves from cold temperatures, H. axyridis individuals move inside dwellings and buildings and form large aggregations in concealed portions of structures to overwinter. The aggregating beetles are responsible for some annoyances due to, on one hand, the number of individuals inside homes and, on the other hand, the hemolymph secretions they release when they are disturbed, which can cause allergic reactions. In order to highlight the specific features of infested houses, we investigated a large number of overwintering sites in Wallonia between 2007 and 2011. These sites were characterized through a survey sent to homeowners confronted to invasion problems. This survey was mainly focused on a general description of the infested house (type, colour, infested floor(s), building material), the orientation of the colonized rooms and the position of the beetles’ cluster. The collected data indicate that H. axyridis preferentially selects isolated brick houses with red or white fronts to take shelter. Aggregations are mostly located at the first floor, essentially inside south, west or southwest oriented rooms. Furthermore, ladybeetles generally gathered into wooden windows frames facing south, west or southwest and to a lesser extent, in the upper corners of walls presenting the same orientation. All these results contribute to improve the knowledge on the aggregative behaviour of H. axyridis and could promote the development of more specific and efficient management methods to prevent massive infestations into dwellings, such as artificial shelters or trapping systems located at the outside of buildings. [less ▲]

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See detailCharacterization of hemicellulosic fractions from spelt hull extracted by different methods
Escarnot, Emmanuelle; Aguedo, Mario ULg; Paquot, Michel ULg

in Carbohydrate Polymers (2011), 85

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See detailCharacterization of hepatitis C virus-induced nasal mucosa remodelling.
El Shazly, Amr ULg; Arafa, Mohammad; Roncarati, Patrick ULg et al

in Histopathology (2010), 57(3), 488-92

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See detailCharacterization of hyperporous polyurethane-based gels by non-intrusive mercury porosimetry
Pirard, René ULg; Rigacci, Arnaud; Marechal, Jacqueline ULg et al

in Polymer (2003), 44(17), 4881-4887

Evaporative drying of polyurethane-based gels produces xerogels. Supercritical drying after replacement of interstitial liquid by supercritical CO2 produces aerogels. SEM micrographs show that both ... [more ▼]

Evaporative drying of polyurethane-based gels produces xerogels. Supercritical drying after replacement of interstitial liquid by supercritical CO2 produces aerogels. SEM micrographs show that both materials are made up of small size particles gathered up in filament-shaped, strongly cross-linked aggregates. Density measurements show that they both have a large pore volume. When submitted to mercury porosimetry, the behavior of these materials is similar to that of inorganic aerogels, as previously observed. Mercury does not penetrate the pore network, but the whole material is densified. The usual Washburn equation cannot be used to analyze the mercury porosimetry. A well-suited equation based on a buckling model of filament-shaped aggregates has been developed in order to determine the pore volume distribution of mineral dried gels. This equation is also valid for analyzing the texture of organic hyperporous materials like polyurethane dried nanoporous gel. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailCharacterization of interspecific recombinants generated from closely related bovine herpesviruses 1 and 5 through multiple PCR sequencing assays
Del Médico Zajac, M. P.; Romera, S. A.; Ladelfa, M. F. et al

in Journal of Virological Methods (2009)

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See detailCharacterization of intestinal cnf1+ Escherichia coli from weaned pigs
Toth, I.; Oswald, E.; Mainil, Jacques ULg et al

in International Journal of Medical Microbiology (2000), 290

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See detailCharacterization of inulin stored at different relative humidities by MDSC and X-ray diffraction, related to soption isotherms.
Ronkart, Sébastien; Fougnies, C.; Paquot, Michel ULg et al

Poster (2004, December)

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See detailCharacterization of ionospheric irregularities and their influence on high-accuracy positioning with GPS over mid-latitudes
Wautelet, Gilles ULg

Doctoral thesis (2013)

Over the last decade came major breakthroughs in satellite navigation and positioning, due to the development of precise positioning techniques based on Global Positioning System (GPS) signals. Modern ... [more ▼]

Over the last decade came major breakthroughs in satellite navigation and positioning, due to the development of precise positioning techniques based on Global Positioning System (GPS) signals. Modern processing methods, such as the Real-Time Kinematics (RTK), allow the GPS user to determine its position in real-time with an accuracy of a few centimeters. The success of these algorithms relies on the cancellation and/or the mitigation of the various errors affecting signal propagation. Among these errors is the delay due to the ionospheric refraction. More particularly, the presence of irregularities in the ionospheric plasma is responsible for positioning errors reaching several (deci)meters. As a result, there is a growing demand from GPS user communities (such as land surveyors or civil engineers) to be informed, if possible in advance, of the occurrence of irregularities that might impact on their positioning solution. Based on a ten years GPS dataset collected over Belgium, this thesis aims at assessing, understanding and modeling the occurrence of ionospheric irregularities as well as estimating their effects in terms of positioning accuracy. Firstly, we carry out a climatological study of irregularities to identify and characterize the most recurrent features. We can distinguish two main irregularity types: those due to space weather events (such as Coronal Mass Ejections – CMEs – or solar flares) and the others, constituting the bulk of irregularities observed at a single station and referred to as “quiet-time” irregularities, as they occur during quiet geomagnetic conditions. These latter are then divided into two groups: the first is made up of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) which occur during autumn/winter daytime. In the second group are the summer nighttime irregularities, which are rapid fluctuations of the Total Electron Content (TEC) probably associated with spread-F phenomenon. Next, we develop a model of quiet-time irregularity occurrence, based on a statistical analysis of the aforementioned dataset. Computations rely on several mathematical modeling tools, such as the Principal Component Analysis (PCA), the Generalized Least-Squares (GLS) algorithm and the AutoRegressive and Moving Average (ARMA) method. The resulting climatological model is made up of two components reproducing daily profile as well as secular variations of the ionospheric variability for a typical GPS station in Belgium. The last part of this work deals with the impact of irregularities on relative positioning. This technique allows the measurement of the vector (called baseline) joining the receiver (user station) to a reference station whose position is accurately known. More precisely, we assess the effect of baseline length and orientation during the occurrence of MSTIDs and geomagnetic storms through the processing of the Belgian Dense Network, made up of 66 dual-frequency GPS stations. Finally, the relationship between positioning error and the presence of ionospheric irregularities detected at a single station is investigated, filling the gap between the scientific and the GPS-user communities. [less ▲]

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See detailCharacterization Of Kenyan Isolates Of Fusarium Udum From Pigeonpea [Cajanus Cajan (L.) Millsp.] By Cultural Characteristics, Aggressiveness And Aflp Analysis
Kiprop, E. K.; Baudoin, Jean-Pierre ULg; Mwang'Ombe, A. W. et al

in Journal of Phytopathology-Phytopathologische Zeitschrift (2002), 150

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See detailCharacterization of lactic acid bacteria isolated from poultry farms in Senegal
Coulibaly, Ibourahema ULg; Dubois Dauphin, Robin ULg; Destain, Jacqueline ULg et al

in African Journal of Biotechnology (2008), 7(12), 2006-2012

The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known and these organisms have been characterized extensively by using different techniques. In this study ... [more ▼]

The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known and these organisms have been characterized extensively by using different techniques. In this study, thirty lactic acid bacterial strains were isolated from soils chicken faeces and feathers. A total of nineteen isolates were obtained and by sequential screening for catalase activity and Gram-staining, eight were determined to be LAB out of which six were established to be homofermentative by the gel plug test. Five isolates were identified by use of the API 50CHL kit and four Lactobacilli strains and one Lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The Lactobacilli strains, both isolated from faeces, produced higher amounts of cells and lactic acid from soils as compared to the lactococci strain isolated from feathers. L (+)-lactic acid is the only optical isomer for use in pharmaceutical and food industries because is only adapted to assimilate this form. The optical isomers of lactic acid were examined by L (+) and D (-) lactate dehydrogenase kit. Lactobacilli strains produced combination of both optical isomers of lactic acid. Among them, Lactobacillus casei subsp. casei produced the low amount of D (-)-lactic (2%). The optimum rates of glucose for lactic acid production by Lactobacillus strains were 180 and 120 g/l for Lactobacillus plantarum and Lactobacillus paraplantarum, respectively. [less ▲]

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See detailCharacterization of Lactobacillus strains isolated from Algerian children faeces for their probiotic properties
Bahri, F.; Lejeune, Annick ULg; Dubois-Dauphin, R. et al

in African Journal of Microbiology Research [=AJMR] (2014), 8(3), 297-303

Lactic acid bacteria termed probiotics have preventive as well as curative effects on several types of diarrhoea of different aetiologies. The main objective of this study was to screen lactobacilli ... [more ▼]

Lactic acid bacteria termed probiotics have preventive as well as curative effects on several types of diarrhoea of different aetiologies. The main objective of this study was to screen lactobacilli strains having probiotic traits, isolated from Algerian healthy children faeces on the purpose of using them further in children diarrheal illnesses. One hundred and twenty (120) lactic acid bacteria isolates were selected from faecal samples of healthy Algerian children aged between five and ten years. Gram positive rods and catalase negative bacteria (52 isolates) were screened, in vitro, for their probiotic potential properties including ability to survive in simulated gastro-intestinal conditions, adherence to Caco-2 cells and their antimicrobial activity. The results show that only five strains resisted in simulated gastric juice at pH 1.5 and pepsin. Four of them were resistant to simulated intestinal conditions at pH 8 and pancreatin and have a good adherence. In the end, three of them were retained as they display interesting probiotic profiles characterized by a strong antimicrobial effect against some intestinal pathogenic bacteria. They were identified by 16S rDNA sequencing as Lactobacillus plantarum F12, Lactobacillus brevis G6 and Lactobacillus paracasei B13. [less ▲]

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See detailCharacterization of lactogen receptor-binding site 1 of human prolactin
Kinet, Sandrina; Goffin, Vincent; Mainfroid, Véronique et al

in Journal of Biological Chemistry (1996), 271(24), 14353-60

Prolactin (PRL) binds to two molecules of PRL receptor (PRLR) through two regions referred to as binding sites 1 and 2. Although binding site 1 has been generally assigned to the pocket delimited by helix ... [more ▼]

Prolactin (PRL) binds to two molecules of PRL receptor (PRLR) through two regions referred to as binding sites 1 and 2. Although binding site 1 has been generally assigned to the pocket delimited by helix 1, helix 4, and the second half of loop 1, the residues involved in receptor binding have not yet all been precisely identified. In an earlier alanine-scanning mutational study, we identified three major binding determinants in loop 1 of human PRL (hPRL) (Goffin, V., Norman, M. & Martial, J. A.(1992) Mol. Endocrinol. 6, 1381-1392). Here we focus on the two other regions that form binding site 1, namely helices 1 and 4. Putative binding residues, selected on the basis of a three-dimensional model of hPRL constructed in this laboratory, were mutated to alanine, and recombinant hPRL mutants produced in Escherichia coli were tested for their ability to bind to the PRLR and to stimulate Nb2 cell proliferation. We thus identified nine single mutations (three in helix 1 and six in helix 4) whose effect was to reduce both binding and mitogenic activity by more than half as compared with wild-type hPRL, indicating the functional involvement of the corresponding residues. Adding these to the three binding determinants identified in loop 1, we now propose a complete picture of PRLR-binding site 1 of hPRL. As we earlier hypothesized, the binding site 1 determinants of hPRL differ from those of human growth hormone, a hPRL homolog. [less ▲]

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See detailCharacterization of marine CaCO3 particles in the context of Global Change
Aerts, Katrien; Godoi, Ricardo; Harlay, Jérôme ULg et al

Poster (2003, January 07)

The expected increase in greenhouse gasses concentrations as a result of human activity is leading to significant climate change in the coming years. The fate of the anthropogenic CO2 has been intensively ... [more ▼]

The expected increase in greenhouse gasses concentrations as a result of human activity is leading to significant climate change in the coming years. The fate of the anthropogenic CO2 has been intensively studied. Being the largest reservoir of reactive carbon, the ocean acts as an important sink for anthropogenic CO2 and plays a significant role on the global biogeochemical cycle of carbon and its perturbations. There remain, however, large uncertainties concerning the uptake of carbon by the ocean, mainly due to insufficient knowledge of processes controlling the carbonate chemistry in surface waters. The effects of precipitation of calcium carbonate by calcifying organisms in the euphotic zone and redissolution of their skeletons have not been fully taken into account. This precipitation-dissolution process affects both the concentration of dissolved inorganic carbon and of total alkalinity and plays thus a significant role in the buffering capacity of seawater and its potential to act as a sink or a source of CO2 for the atmosphere. We aim to study the processes associated with the oceanic production and dissolution of CaCO3 in order to quantify the role of calcifying phytoplanktonic organisms in sequestering CO2. The calcareous skeletons of Coccolithophores, which comprise one of the main groups of calcifying organisms in the photic zone of the ocean, are analysed. The gut content of copepods, which grazes on coccolithophores is examined by different methods like Electron Probe Micro-Analysis (EPMA) and Micro X-Ray Fluorescence (M-XRF) in order to detect the possible dissolution features at the calcite surface. Automatic EPMA is used for the characterization of individual particles from ocean samples for their composition, morphology and size. Subsequent statistical processing techniques classifies the particles into specific particle clusters. [less ▲]

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See detailCharacterization of material for cement production in Mbuji-Mayi area (DR Congo)
Matamba Jibikila, Raphaël ULg; Pirard, Eric ULg

in ACCTA johannesburg 2013 (2013)

Although the City of Mbuji-Mayi (DR Congo) is rich in limestone and clay deposits, cement and other building materials are still being imported sometimes by plane from Kinshasa, Zambia and Tanzania. A ... [more ▼]

Although the City of Mbuji-Mayi (DR Congo) is rich in limestone and clay deposits, cement and other building materials are still being imported sometimes by plane from Kinshasa, Zambia and Tanzania. A consequence of this situation is low consumption of cement and concrete (less than 1kg per capita) and a lack of modern and sustainable infrastructures. Our study provides a qualitative assessment of all cement raw materials available in the region, including limestone and clay in order to produce hydraulic binder with optimized technical and environmental performances. Chemical and mineralogical characterizations were done using XRF spectroscopy and X-ray diffraction (XRD). Thermal analysis, electron microscopy, and mechanical characterizations are planned to assess the performance of the concrete and mortar manufactured with the binder produced. Finally, the ultimate goal is to produce a local hydraulic binder whose physical and mechanical characteristics are similar to those of Portland cement, but whose production is expected to consume less energy and emit less CO2. [less ▲]

Detailed reference viewed: 33 (2 ULg)