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See detailCharacteristics of the infestation of Seriatopora corals by the coral gall crab Hapalocarcinus marsupialis Stimpson, 1859 on the great reef of toliara, Madagascar
Terrana, Lucas; Caulier, Guillaume; Todinanahary, Gildas et al

in Symbiosis (2016), 69(2), 113-122

This study describes the association between the obligatory symbiont coral gall crab Hapalocarcinus marsupialis and its stony coral hosts Seriatopora sp .within the Great Reef of Toliara in Madagascar and ... [more ▼]

This study describes the association between the obligatory symbiont coral gall crab Hapalocarcinus marsupialis and its stony coral hosts Seriatopora sp .within the Great Reef of Toliara in Madagascar and attempts to dis- cuss their symbiotic status through comparison with previous studies. These corals are inhabited by crabs living in galls that can be categorised in four distinct morphological stages, where the first one corresponds to a small bud and the last one represents a completely closed gall surrounding the crab inside. Within the reef, 563 colonies of Seriatopora species were observed by scuba-diving at ten different stations: 37.8 % of them were infested by H. marsupialis , with a total of 763 galls, and with a majority of stage 4 galls. Galls are monopolised by females that can have different morphologies. Females store the sperm in two spermathecae and are fertilised when their morphology and size are similar to males and the gall is not closed. Histological observations coupled with scanning electronic microscopy analyses show that closed galls are made of an external living tissue, a mid skeletal layer and an internal living tissue. The internal living tissue includes polyps similar to the external tissue, some of them being sex- ually mature. Nitrogen and carbon isotopic signatures confirmed that these crabs are filter-feeders and do not feed on their host. This association perfectly highlights the difficul- ties to define the symbiotic status of a symbiont if one con- siders inflexible the three categories of symbiosis commonly defined. [less ▲]

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See detailCharacteristics of the iron moment in Dy-Fe and Dy-FeCo amorphous alloys studied by X-ray magnetic circular dichroism
Fleury-Frenette, Karl ULg; Dhesi, S. S.; van der Laan, G. et al

in Journal of Magnetism & Magnetic Materials (2000), 220(1), 45-51

The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic ... [more ▼]

The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic moments have been obtained for a range of alloy compositions by applying the sum rules to the XMCD spectra. The room temperature variations of the average components of the Fe moments as a function of Dy concentration and with the substitution of Fe by Co have been determined. A sharp reversal of the total magnetic moment was found at 28 +/- 1 at% Dy for both alloys. (C) 2000 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailThe characteristics of the O2 Herzberg II and Chamberlain bands observed with VIRTIS/Venus Express
Migliorini, A.; Piccioni, G.; Gérard, Jean-Claude ULg et al

in Icarus (2013)

The oxygen Venus nightglow emissions in the visible spectral range have been known since the early observations from the Venera spacecraft. Recent observations with the VIRTIS instrument on board Venus ... [more ▼]

The oxygen Venus nightglow emissions in the visible spectral range have been known since the early observations from the Venera spacecraft. Recent observations with the VIRTIS instrument on board Venus Express allowed us to re-examine the Herzberg II system of O2 and to further study its vertical distribution, in particular the (0–m00 with m00 = 7–13) bands. The present work describes the vertical profile of the observed bands and relative intensities from limb observation data. The wavelength-integrated intensities of the Herzberg II bands, with m00 = 7–11, are inferred from the recorded spectra. The resulting values lie in the range of 84–116 kR at the altitudes of maximum intensity, which are found to lie in the range of 93–98 km. Three bands of the Chamberlain system, centered at 560 nm, 605 nm, and 657 nm have been identified as well. Their emission peak is located at about 100 km, 4 km higher than the Herzberg II bands. For the first time, the O2 nightglow emissions were investigated simultaneously in the visible and in the IR spectral range, showing a good agreement between the peak position for the Herzberg II and the O2ða1Dg—X3R g Þ bands. An airglow model, proposed by Gérard et al. (Gérard, J.C., Soret, L., Migliorini, A., Piccioni, G. [2012]. Icarus.) starting from realistic O and CO2 vertical distributions derived from Venus-Express observations, allows reproduction of the observed profiles for the three O2 systems. [less ▲]

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See detailCharacteristics of the pulsatile liberation of LH in Italian Simmental cows from the dry period to early lactation
Prandi, Alberto; Motta, Mario; Rossi, A. et al

in Bulletin des Recherches Agronomiques de Gembloux (1995), 30

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See detailCharacteristics of the size distribution of recent and historical landslides in a populated hilly region
Van den Eeckhaut, M.; Poesen, J.; Govers, G. et al

in Earth and Planetary Science Letters (2007), 256(3-4), 588-603

Despite the availability of studies on the frequency density of landslide areas in mountainous regions, frequency-area distributions of historical landslide inventories in populated hilly regions are ... [more ▼]

Despite the availability of studies on the frequency density of landslide areas in mountainous regions, frequency-area distributions of historical landslide inventories in populated hilly regions are absent. This study revealed that the frequency-area distribution derived from a detailed landslide inventory of the Flemish Ardennes (Belgium) is significantly different from distributions usually obtained in mountainous areas where landslides are triggered by large-scale natural causal factors such as rainfall, earthquakes or rapid snowmelt. Instead, the landslide inventory consists of the superposition of two populations, i.e. (i) small (<1-2 . 10(-2) km(2)), shallow complex earth slides that are at most 30 yr old, and (ii) large (> 1-2 . 10(-2) km(2)), deep-seated landslides that are older than 100 yr. Both subpopulations are best represented by a negative power-law relation with exponents of -0.58 and -2.31 respectively. This study focused on the negative power-law relation obtained for recent, small landslides, and contributes to the understanding of frequency distributions of landslide areas by presenting a conceptual model explaining this negative power-law relation for small landslides in populated hilly regions. According to the model hilly regions can be relatively stable under the present-day environmental conditions, and landslides are mainly triggered by human activities that have only a local impact on slope stability. Therefore, landslides caused by anthropogenic triggers are limited in size, and the number of landslides decreases with landslide area. The frequency density of landslide areas for old landslides is similar to those obtained for historical inventories compiled in mountainous areas, as apart from the negative power-law relation with exponent -2.31 for large landslides, a positive power-law relation followed by a rollover is observed for smaller landslides. However, when analysing the old landslides together with the more recent ones, the present-day higher temporal frequency of small landslides compared to large landslides, obscures the positive power-law relation and rollover. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailCharacteristics of Urban Food Insecurity: The Case of Kinshasa
Lebailly, Philippe ULg; Muteba Kalala, Damien ULg

in African Review of Economics and Finance (2011), 3(1), 58-68

Feeding Kinshasa? How to ensure food security for millions of inhabitants who have to survive on low wages well below the poverty line? This is the daily challenge for a multitude of poor people in ... [more ▼]

Feeding Kinshasa? How to ensure food security for millions of inhabitants who have to survive on low wages well below the poverty line? This is the daily challenge for a multitude of poor people in Kinshasa! Some see this situation as an opportunity for strengthening local producers. In the Democratic Republic of Congo (DRC), the constraints affecting the agricultural economy mean it cannot supply the city of Kinshasa on the basis of predominantly local production but through food imports. In a context of crisis as experienced in the DRC, food is of strategic importance and the focus is essentially on quantity: households turn to cheaper products and high calorie intake at the expense of high-protein foods, leading to unbalanced diets. This imbalance is exacerbated by an influx of imported products, often of poor nutritional quality but at very competitive prices and responding to new eating habits of urban consumers. To understand the issue of food security in DRC, a country with high agricultural potential but 70% of whose population is affected by food insecurity, various research devices have been established by an interdisciplinary research group to support policy, funded by the Belgian Development Cooperation Department (DGDC / CUD): the Research Group Supporting the Policy for Food and Agriculture in Africa (GRAP 3A). This paper presents one of the main focuses of the inter-university research program conducted jointly with researchers from the University of Kinshasa: an approach to food insecurity and strategies for a sustainable food policy based on the study of household food consumption in Kinshasa carried out by various surveys. [less ▲]

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See detailCharacterization of Clostridium perfringens isolates from goats.
Phukan, A.; Dutta, G.-N.; Daube, Georges ULg et al

in Indian Veterinary Journal (The) (1997), 74

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See detailCharacterization and Adsorption Study of Thymol on Pillared Bentonite
El Miz, Mohamed; Salhi, S.; Chraibi, I. et al

in Open Journal of Physical Chemistry (2014), 4(3), 98-116

Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of ... [more ▼]

Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 Å, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg∙g−1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R² ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min. [less ▲]

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See detailCharacterization and biocontrol properties of Lactuca sativa rhizosphere microbiota in an aquaponic system
Stouvenakers, Gilles ULg; Massart, Sébastien ULg; Jijakli, Haissam ULg

Poster (2016, May 17)

Aquaponics is an integrated recirculated system that combines aquaculture and hydroponic plant production. The dissolved nutrients generated by the fish rearing after bacterial activities are used by the ... [more ▼]

Aquaponics is an integrated recirculated system that combines aquaculture and hydroponic plant production. The dissolved nutrients generated by the fish rearing after bacterial activities are used by the plants for their growth. This uptake reduces the accumulation of some molecules which allow a longer water recirculation. When comparing growth conditions between aquaponics and hydroponics, we observed much lower concentration of several key nutrients in aquaponics. Nevertheless, several experimentations report similar or better yield in aquaponics compared with hydroponics. One explanation of this phenomenon could be linked to microbial actions. Nowadays, microorganisms related to aquaculture and hydroponics are well characterized but very little is known about the microbiota associated with aquaponic system. The first aim of this study is to characterize the rhizosphere microbiota (metagenomics) of lettuces growing in an aquaponics system. A NGS approach targeting the 16S rDNA will be carried out to evaluate the bacterial composition and diversity. The second aim is to assess the resistance of aquaponics lettuces following a pest introduction. Yields, symptoms and microbial changes due to the pest will be recorded and analysed to determine if aquaponics systems provide a better plant protection than hydroponics. Depending on the results, the final steps will be to identify the optimal conditions for the management of the potential beneficial microbiota or isolate a beneficial microorganism. [less ▲]

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See detailCharacterization and Cloning of Chitin Deacetylases from Rhizopus Circinans
Gauthier, Carole ULg; Clerisse, Fabienne ULg; Dommes, Jacques ULg et al

in Protein Expression & Purification (2008), 59

Chitin deacetylase catalyzes hydrolysis of the acetamido groups of N-acetylglucosamine of chitin in fungal cell walls. Here a chitin deacetylase secreted by Rhizopus circinans was purified to homogeneity ... [more ▼]

Chitin deacetylase catalyzes hydrolysis of the acetamido groups of N-acetylglucosamine of chitin in fungal cell walls. Here a chitin deacetylase secreted by Rhizopus circinans was purified to homogeneity and partially characterized. The enzyme exhibits an apparent molecular weight of approximately 75kDa. At 37 degrees C it shows optimal activity at pH 5.5-6. Its pH stability and thermal stability are good. Mn(2+) and Mg(2+) slightly enhance the activity of the enzyme and Cu(2+) strongly inhibits it. An R. circinans cDNA library was constructed and screened with a homologous probe synthesized by RT-PCR or with synthetic primers derived from the N-terminal amino-acid sequence of the native purified chitin deacetylase. Three chitin deacetylase cDNAs (RC, D2, and I3/2) were isolated from the cDNA library and sequenced. These cDNAs exhibit features characteristic of chitin deacetylase sequences: the presence of a polysaccharide deacetylase domain, a metal-binding triad, the conserved catalytic residues, and high homology with various chitin deacetylase genes. The cDNAs were cloned in a Pichia pastoris expression system and produced as polyhistidine-tagged proteins. Only one recombinant enzyme (called RC) was active under the tested conditions. It was purified to homogeneity in a single step and further characterized. The protein showed an apparent molecular mass of approximately 75kDa and, like the native enzyme, showed optimal activity at pH 5.5-6 at 37 degrees C. It was strongly inhibited by Cu(2+). The isolation of several chitin deacetylase cDNAs from the same microorganism is discussed. [less ▲]

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See detailCharacterization and dynamics of the auroral electron precipitation during substorms deduced from IMAGE-FUV
Meurant, M.; Gérard, Jean-Claude ULg; Hubert, Benoît ULg et al

in Journal of Geophysical Research. Space Physics (2003), 108(A6),

[1] The FUV imager on board the IMAGE satellite provides simultaneous images of the north polar aurora every 2 min in three spectral channels. The Wideband Imaging Camera (WIC) responds primarily to the N ... [more ▼]

[1] The FUV imager on board the IMAGE satellite provides simultaneous images of the north polar aurora every 2 min in three spectral channels. The Wideband Imaging Camera (WIC) responds primarily to the N-2 LBH bands while one of the Spectral Imagers (SI13) includes the OI 135.6 nm emission and nearby LBH bands. The third channel (SI12) is sensitive to Doppler-shifted Lyman-alpha emission at 121.8 nm generated by proton precipitation. The relative magnitude of the WIC and SI13 signals depends on the altitude distribution of the energy deposition, in response to the differential O-2 absorption and the altitude dependence of the neutral composition. The ratio of simultaneous images from WIC and SI13 is used to derive the spatial distribution of the characteristic energy of the precipitating auroral electrons and the energy flux they carry. The method is described and the uncertainties introduced by possible perturbations of the neutral composition known to occur in the auroral thermosphere are discussed. The first part of this study describes a validation of this method performed by comparing precipitation characteristics derived from FUV with in situ measurements from two coincident passes of the NOAA-16 satellite. They are shown to agree within about 45%. The second part applies this ratio method to analyze the time evolution of auroral activity which occured during two substorms on 28 October 2000. The time evolution is displayed in the form of magnetic local time and magnetic latitude keograms. It is shown that the pattern of the electron average energy distribution exhibits both spatial and temporal changes. Comparison with FAST in situ electron spectrograms confirms the ability of IMAGE to detect precipitation events with a similar to200 km spatial scale. However the characteristics of the physical process leading to electron acceleration cannot be identified with FUV. The highest values of the average energy are colocated in time and space with the largest electron precipitation fluxes. A dawnward motion of bright features is observed in the postmidnight at speeds on the order of 5 magnetic local time hours/UT hour. [less ▲]

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See detailCharacterization and impact of reduced copper plating overburden on 45 nm interconnect performances
Dubreuil, Olivier ULg; Caubet-Hilloutou, Véronique; Guillan, Julie et al

in Microelectronic Engineering (2010, March), 87(3),

During first metal level interconnects fabrication, a controlled modification of the electro-deposited copper over-deposition (overburden) is performed using a partial chemical–mechanical polishing (CMP ... [more ▼]

During first metal level interconnects fabrication, a controlled modification of the electro-deposited copper over-deposition (overburden) is performed using a partial chemical–mechanical polishing (CMP) step. Next, copper microstructure is stabilized with a short duration hot-plate anneal. Overburden is then removed during CMP end-of-step. Ionic microscopy and EBSD observations of overburden thickness reduction reveal that copper grain growth occurs differently, according to patterned geometries and with a strong (1 1 1) texture, as observed in modified films. Reduction of overburden thickness also reveals the capacity of anneal temperature to impact electrical performances. Reliability is impacted for thinnest wires. [less ▲]

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See detailCharacterization and modeling of a scroll expander with air and ammonia as working fluid
Mendoza, Luis Carlos; Navarro-Esbrí; Bruno, Joan Carles et al

in Applied Thermal Engineering (2014), 70

This paper presents the experimental characterization and modeling of a scroll expander. The expander used here is a scroll compressor modified to work as an expander. It is characterized in two ... [more ▼]

This paper presents the experimental characterization and modeling of a scroll expander. The expander used here is a scroll compressor modified to work as an expander. It is characterized in two experimental setups using air and ammonia as working fluids. The paper studies how the main operating variables (supply pressure and temperature, pressure ratio, rotational speed and lubrication) influence the performance of the scroll expander. A semi-empirical model is proposed to determine the scroll expander performance. This model uses some semi-empirical parameters (such as built-in volume ratio, leakage area and mechanical losses), obtained through experimentation, to calculate the mechanical power, supply mass flow rate and exhaust temperature. Using this semi-empirical model, the deviations in the calculated mechanical power, exhaust temperature and supply mass flow rate are ±9%, ±4 K and ±5% Hz. [less ▲]

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See detailCharacterization and modelling of a digital micromachined accelerometer
Kraft, Michaël ULg; Lewis, Christopher P.; Hesketh, Thomas G.

in ICSEng '96 - 11th International Conference on Systems Engineering (1995)

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See detailCharacterization and modelling of a micromachined accelerometer
Lewis, Christopher P.; Hesketh, Thomas G.; Kraft, Michaël ULg

in Proceedings of the 12th International Conference on Systems Science (1996)

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See detailCharacterization and Numerical Simulation of the Jovian UV Aurora Observed with the HST Cameras
Grodent, Denis ULg; Dols, V.; Gérard, Jean-Claude ULg et al

in Science with the Hubble Space Telescope - II (1996)

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See detailCharacterization and optimization of GMO-based gels with long term release for intraarticular administration
Réeff, J.; Gaignaux, A.; Goole, J. et al

in International Journal of Pharmaceutics (2013), 451(1-2), 95-103

Osteoarthritis is characterized by slow degenerative processes in the articular cartilage within synovial joints. It could be interesting to develop a sustained-release formulation that could be effective ... [more ▼]

Osteoarthritis is characterized by slow degenerative processes in the articular cartilage within synovial joints. It could be interesting to develop a sustained-release formulation that could be effective on both pain/inflammation and restoration of mechanical integrity of the joint. Recently, an injectable system based on glycerol monooleate (GMO), containing clonidine as a model hydrophilic analgesic/anti-inflammatory drug and hyaluronic acid as a viscoelastic scaffold, showed promising potential as a biodegradable and biocompatible preparation to sustain the drug activity. However, drug release from the system is relatively fast (complete within 1 week) and the underlying drug release mechanisms not fully understood. The aims of this study were: (i) to significantly improve this type of local controlled drug delivery system by further sustaining clonidine release, and (ii) to elucidate the underlying mass transport mechanisms. The addition of FDA-approved inactive ingredients such as sodium oleate or purified soybean oil was found to be highly effective. The release rate could be substantially reduced (e.g., 50% release after 10 days), due to the increased hydrophobicity of the systems, resulting in slower and reduced water uptake and reduced drug mobility. Interestingly, Fick's second law of diffusion could be used to quantitatively describe drug release. [less ▲]

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