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See detailPolyphase karst system in Cretaceous chalk and calcarenite of the Belgian-Dutch border
Willems, Luc ULg; Rodet, Joël; Fournier, Matthieu et al

in Zeitschrift für Geomorphologie (2007), 51(3), 361-376

Along the Belgian-Dutch border, underground and surface quarries dug in Cretaceous calcarenite and chalk intersect many karst features as well as deep large nodes of weathered rock. Their observation ... [more ▼]

Along the Belgian-Dutch border, underground and surface quarries dug in Cretaceous calcarenite and chalk intersect many karst features as well as deep large nodes of weathered rock. Their observation allows the reconstruction of the genesis of an original karst system resulting from the merging of initially independent endokarsts and exokarsts. Deep weathering has developed within the Cretaceous formations, creating nodes of weathered chalk and closed cavities. These phenomena are expanded over time and can form interconnected voids. Near the surface, solution pipes are generated under the coarsest deposits of a fluvial terrace capping the Cretaceous formations. These pipes develop vertically and may be related to the progressive lowering of the water table in connection with the incision of the Meuse valley. Some of these phenomena cut up the older endokarsts and organize complex systems of out-flow within the chalk. [less ▲]

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See detailPolyphased karst systems in sandstones and quartzites of Minas Gerais, Brazil
Willems, Luc ULg; Rodet, Joël; Pouclet, André et al

in Proceeding 14th UIS Congress, Athens-Kalamos, 23-28 august 2005, Abstract Book : 71. (2005)

The state of Minas Gerais (Brazil) exhibits several major karst areas located in sandstone and quartzite terrains, that display a complex suite of underground and surface karstic forms. In the Espinhaço ... [more ▼]

The state of Minas Gerais (Brazil) exhibits several major karst areas located in sandstone and quartzite terrains, that display a complex suite of underground and surface karstic forms. In the Espinhaço Ridge, central Minas Gerais, several caves, up to a few hundred metres long, occur in the surroundings of the town of Diamantina. Some of these caves, such as Salitre, represent swallow-holes and show dome pits. Other horizontal caves are characterized by corrosion forms generated into the phreatic zone. In some places, such as in the Rio Preto area, these phreatic forms have been overprinted by ceiling tubes, suggesting a polyphase karst evolution, prior to the draining of the cave. Relicts of passages, with circular cross section up to a metre in diametre, can be found amidst the residual tower-like surface landforms, which constitute a typical scenery in the landscape. Their dissection is due to a generalised karstification in the area, resulting in closed canyons, megakarrens and kamenitzas. In southern Minas Gerais, close to the Mantiqueira Ridge, the caves of the state park of Ibitipoca can extent 2 km in length. These caves are associated with a very large hanging geological syncline. Several of these caves contain active streams, that flow for hundreds of metres before disappearing in sand-choked passages. Keyhole cross sections characterize steeply descending passages in these caves, indicating a change from slow phreatic flow towards a faster vadose flow responsible for the vertical incision of the passage. Such change is probably related to base level lowering and/or to turn in the direction of the water flow. Several generations of wall-pockets, from a few centimetres to over a metre long, occur into the caves. These features are good indicators of the initial phase of speleogenesis, generating the initial conduits by their coalescence. This mechanism is also responsible for cut-off meanders. The main river in the area, which flows along the syncline axis, cuts through a rock barrier, generating a tunnel-like passage. This cave drains, through resurgences in its walls, part of the water that flows in other caves located in the flank of the syncline. The non-carbonate karst features observed in the state of Minas Gerais demonstrate the complex organisation of polyphase karst systems due to the linkage of underground and surface forms not previously connected. As in carbonate areas, these systems may play an important hydrological role. [less ▲]

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See detailA polyphasic approach to assess the cyanobacterial diversity of summer samples from Czech reservoirs
Boutte, Christophe; Komarkova, Jarka; Grubisic, Stana ULg et al

in Algological Studies (2005), 117

We used a polyphasic approach combining data from microscopic assessment of fresh biomass and from clone libraries and DGGE fingerprints based on 16S rRNA gene sequences to investigate the cyanobacterial ... [more ▼]

We used a polyphasic approach combining data from microscopic assessment of fresh biomass and from clone libraries and DGGE fingerprints based on 16S rRNA gene sequences to investigate the cyanobacterial diversity of Czech reservoirs during the summer in 2001 and 2002. In total, 15 genera were identified using the microscopic analysis in 38 samples analysed. They were Aphanizomenon, Anabaena, Anabaenopsis, Aphanocapsa, Aphanothece, Pseudanabaena, Planktothrix, Planktolyngbya, Limnothrix, Woronichinia, Snowella, Romeria, Microcystis, Merismopedia, and Coelomoron. We recovered 113 DGGE band sequences from the same samples. In addition, 128 partial 16S rRNA sequences were obtained from two clone libraries of reservoirs Pilská and Orlík. The phylogenetic comparison with the currently available rRNA sequences in databases showed that our sequences belonged to 8 clusters: Woronichinia, Microcystis, Synechococcus, Snowella, Planktothrix, Anabaena/Aphanizomenon, Limnothrix and a plastid related to Chrysochromulina polylepis. The microscopic enumeration and the molecular results were generally congruent concerning the major populations determined in these samples (for 32 samples among 38). Anabaena/Aphanizomenon, Microcystis and Woronichinia were the major genera in the Czech reservoirs during summer, and were present in most of the samples. This study showed some discrepancies between the genera retrieved by the traditional method and the molecular analyses. Differences concerned the presence of minor populations belonging to Aphanothece, Romeria, Merismopedia, Synechococcus, Snowella and Pseudanabena. These differences could be explained by biases specific to each method (competitive amplification, difficulty to obtain sequences from DGGE bands, not precise microscopic observation of the small-sized genera). [less ▲]

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See detailPolyphasic Identification Of A New Thermotolerant Species Of Lactic Acid Bacteria Isolated From Chicken Faeces
Sow, Nm.; Dubois Dauphin, Robin ULg; Weber, Dominique ULg et al

in African Journal of Biotechnology (2005), 4(5),

Two thermotolerant and desiccation tolerant lactic acid bacteria (TDLAB) were pointed out from twenty isolated strains from soils and dried chicken faeces. Samples were collected in poultry farms in the ... [more ▼]

Two thermotolerant and desiccation tolerant lactic acid bacteria (TDLAB) were pointed out from twenty isolated strains from soils and dried chicken faeces. Samples were collected in poultry farms in the vicinity of Dakar, Senegal (West Africa). The two new isolates were called Sp.4 (Sp.4=CWBI-B534=LMG7278) and Sp.20 (Sp.20=CWBI-B545=LMG7279). They are Grampositive, catalase-negative, facultatively anaerobic, non-motile, and non-spore-forming rods. Both produce D/L lactic acid via homofermentative pathway. Growth of the strains occurred between 15°C and 44°C. The optimum temperature for growth was in 30°C-37°C temperature and pH 3-8 range. Desiccation treatment in glycerol showed 30% survival rates. Complex total fatty acid pattern of the strains showed the presence of C14:0, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3. SDS-PAGE of total protein of both strains placed them in L. plantarum group. AFLP analysis showed a phylogenetic proximity of the two strains with L. plantarum stricto sensu species. Specific amplified 16s rDNA restriction analysis (ARDRA) of the 16S rDNA gene, however, showed that these thermotolerant strains were not L. plantarum. ITS sequencing revealed that Sp.20 (LMG 7279) could be classed into Lactobacillus paraplantarum species since the short sequence of ITS showed 95% of similarity with reference species. Polyphasic identification shows that Sp.4, (the type strain is LMG 7278T) represent a new species within the genus Lactobacillus with only 88%+/-1 ITS sequence similarity with reference species. For which the name Lactobacillus aminata sp. nov. is proposed. [less ▲]

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See detailPolyphasic study of Antarctic cyanobacterial strains
Taton, A.; Grubisic, Stana ULg; Ertz, D. et al

in Journal of Phycology (2006), 42(6), 1257-1270

We isolated 59 strains of cyanobacteria from the benthic microbial mats of 23 Antarctic lakes, from five locations in two regions, in order to characterize their morphological and genotypic diversity. On ... [more ▼]

We isolated 59 strains of cyanobacteria from the benthic microbial mats of 23 Antarctic lakes, from five locations in two regions, in order to characterize their morphological and genotypic diversity. On the basis of their morphology, the cyanobacteria were assigned to 12 species that included four Antarctic endemic taxa. Sequences of the ribosomal RNA gene were determined for 56 strains. In general, the strains closely related at the 16S rRNA gene level belonged to the same morphospecies. Nevertheless, divergences were observed concerning the diversity in terms of species richness, novelty, and geographical distribution. For the 56 strains, 21 operational taxonomic units (OTUs, defined as groups of partial 16S rRNA gene sequences with more than 97.5% similarity) were found, including nine novel and three exclusively Antarctic OTUs. Sequences of Petalonema cf. involvens and Chondrocystis sp. were determined for the first time. The internally transcribed spacer (ITS) between the 16S and the 23S rRNA genes was sequenced for 33 strains, and similar groupings were observed with the 16S rRNA gene and the ITS, even when the strains were derived from different lakes and regions. In addition, 48 strains were screened for antimicrobial and cytotoxic activities, and 17 strains were bioactive against the gram-positive Staphylococcus aureus, or the fungi Aspergillus fumigatus and Cryptococcus neoformans. The bioactivities were not in coincidence with the phylogenetic relationships, but rather were specific to certain strains. [less ▲]

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See detailPolyphenol Content and Modulatory Activities of Some Tropical Dietary Plant Extracts on the Oxidant Activities of Neutrophils and Myeloperoxidase
Tsumbu, César Ndele ULg; Deby-Dupont, Ginette; Tits, Monique ULg et al

in International Journal of Molecular Sciences (2012), 13(1), 628-650

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See detailPOLYPHENOL VARIABILITY IN THE FRUITS AND JUICES OF A CIDER APPLE PROGENY
Verdu, Cindy ULg; Childebrand, Nicolas; Marnet, Nathalie et al

in Journal of the Science of Food and Agriculture (2013)

BACKGROUND: Polyphenols have a favorable antioxidant potential on human health, suggesting that their high content in apple is responsible for the beneficial effects of apple consumption. They are also ... [more ▼]

BACKGROUND: Polyphenols have a favorable antioxidant potential on human health, suggesting that their high content in apple is responsible for the beneficial effects of apple consumption. They are also linked to the quality of apple juices and ciders since they are predominantly responsible for astringency, bitterness, color and aroma. Major phenolic compounds were quantified by liquid chromatography in fruits and juices from a cider apple progeny harvested for three years. The total content of procyanidins and their average degree of polymerization (DPn) were also determined in fruits by phloroglucinolysis. Variability and extraction yield of these compounds were determined. RESULTS: The variability observed in the progeny was representative of the variability observed in many cider apple varieties. Hydroxycinnamic acids were the most extractable group, with an average extraction yield of 67%, whereas flavonols and anthocyanins were the least. CONCLUSION: This study is the first one to introduce variability and extraction yields of the main phenolic compounds in both fruits and juices of a cider apple progeny. This dataset will be used for an upcoming QTL mapping study, an original approach that has never been undertaken for cider apple. [less ▲]

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See detailPolyphonies éditoriales au Musée royal de Mariemont
Bawin, Julie ULg

in Art Même : Chronique des Arts Plastiques de la Communauté française de Belgique (2007), (37), 42-43

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See detailThe polyphony of public funding instruments in science and innovation policy
Fallon, Catherine ULg

Scientific conference (2012, March 15)

During the last decennia, the Walloon region in Belgium has launched new instruments to strategically fund university research. A new program called "Poles of Competitiveness" supports collaborative ... [more ▼]

During the last decennia, the Walloon region in Belgium has launched new instruments to strategically fund university research. A new program called "Poles of Competitiveness" supports collaborative research between industry and universities (Fallon & Delvenne 2010). Public funds support public-private partnerships between firms and universities. These new instruments interfere with established forms of distributed governance: industry partners are called upon to take the lead in the strategic management of large research programs and universities entered rapidly the game, while the regional administration are put on the side. Based on field research (Fallon 2011), the paper will discuss the impact of this transformation on the spaces of interactions between the actors of the STI regime: university, researchers, public administration, industry and stakeholders (Lepori 2011), all struggling for the definition of settings of participation and of administrative and political control (Buisson-Fenet 2008). We put in the fore historic and recent transformations of these socio-political spaces, to apprehend the complexity of institutions, norms, discourses and networks of the different stakeholders and to analyse how they adapted to the new set of policy instruments. In reference to the new avenue for public policy analysis of the "instruments in action" (Lascoumes & Le Galès 2007), we consider instrument as socio-technical device, carrying a concrete concept of the politics/society relationship, as well as meanings and representations. The choice of an instrument itself is a dynamic translation process (Callon 1986) and the use of methodological approaches derived from ANT help unveil the dynamics of institutional innovation and organisational learning: the researcher observes how actors mobilise objects and are being constrained by them, giving shape to internal procedures of categorisation and hierarchisation, with identification processes contributing to the definition of institutional boundaries (Douglas, 1986). The fieldwork thoroughly deconstructed emerging policy instruments and put them in perspective with the other policy support schemes used by the same researchers. The analysis of the transformation / emergence of instruments contributes to illuminate the diversity of networks, in terms of forms of cooperation, heterogeneity, power relations, time perspectives and representations. This instrumental polyphony can be considered as an asset, particularly for those researchers capable of strategically using them (Shinn & Lamy 2006). An instrument is dynamic, undergoing continuous transformation to adapt to contingency (Rayner 1986). Eg. the research council FNRS was settled in 1927 as a structure of collegiality and it consistently refused to become a part of a formal administration with its specific hierarchy. Recent transformations show confrontation of the logic of mutuality with a logic of global marketisation. In order to enrich the theoretical discussions, we propose to confront the propositions derived from the culturalist approach of coordination schemes (the grid/group cultural theory by Douglas (1986) and mobilised by Hood (1998) distinguishes four basic organizational types: hierarchic, fatalist, egalitarian and individualist; each of them favouring a specific mode of cooperation and control : random /mutuality /hierarchy / market) with the lessons we could learn by using the conceptual framework proposed by Lepori (2011). In their review of the "institutional dynamics of culture", 6 & Mars (2008) showed how the work of Douglas (1986) permeated most disciplines of social sciences: considering the four basic institutional forms of Douglas (1986), researchers further analysed how "anomalies" (anomalies under the system of classification that operate in a given institutional setting) are signs of on going hybridisation and social change (Thompson 1996) grounded on endogenous institutional dynamics. Made visible through a fieldwork mapping emerging hybrid forms, conflicts between the institutional forms are to be analysed as drivers of change. This is also central in the work launched by Hood on the "Art of the State" (1998) when considering the limited forms of institutional coordination to be found in public administrations and in the analysis of policy instruments. [less ▲]

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See detailPolyphosphate-based copolymers for drug delivery applications
Lecomte, Philippe ULg

Conference (2013, April 09)

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See detailPolyplexes Targeting Angiogenesis in Cancer
Frère, Antoine ULg; Peixoto, Paul ULg; Kawalec, Michal et al

Poster (2014, April)

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See detailPolyploid formation in cotton is not accompanied by rapid genomic changes
Liu, B.; Brubaker, Cl.; Mergeai, Guy ULg et al

in Genome (2001), 44(3), 321-330

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See detailPolysaccharide-coated PCL nanofibers for wound dressing applications
Croisier, Florence ULg; Atanasova, Ganka; Poumay, Yves et al

in Advanced Healthcare Materials (2014), 3(12), 2032-2039

Polysaccharide-based nanofibers with amultilayered structure are prepared by combining electrospinning (ESP) and layer-by-layer (LBL) deposition techniques. Charged nanofibers are firstly prepared by ... [more ▼]

Polysaccharide-based nanofibers with amultilayered structure are prepared by combining electrospinning (ESP) and layer-by-layer (LBL) deposition techniques. Charged nanofibers are firstly prepared by electrospinning poly(ε-caprolactone) (PCL) with a block-copolymer bearing carboxylic acid functions. After deprotonation of the acid groups, the layer-by-layer deposition of polyelectrolyte polysaccharides, notably chitosan and hyaluronic acid, is used to coat the electrospun fibers. A multilayered structure is achieved by alternating the deposition of the positively charged chitosan with the deposition of a negatively charged polyelectrolyte. The construction of this multi-layered structure is followed by Zeta potential measurements, and confirmed by observation of hollow nanofibers resulting from the dissolution of the PCL core in a selective solvent. These novel polysaccharide-coated PCL fiber mats remarkably combine the mechanical resistance typical of the core material (PCL) – particularly in the hydrated state –, with the surface properties of chitosan. The control of the nanofiber structure offered by the electrospinning technology, makes the developed process very promising to precisely design biomaterials for tissue engineering. Preliminary cell culture tests corroborate the potential use of such system in wound healing applications. [less ▲]

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See detailLa polysémie de la métaphore: Introduction à l’approche cognitive du langage
Perrez, Julien ULg

Scientific conference (2010, February 19)

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See detailPolytropes as simple models of beta Cephei stars
Godart, Mélanie ULg; Scuflaire, Richard ULg; Thoul, Anne ULg et al

in Communications in Asteroseismology (2006), 147

Beta Cephei stars have a simple structure: a convective core surrounded by a radiative envelope. It is therefore worth trying to describe beta Cephei stars with composite polytropes which are useful to ... [more ▼]

Beta Cephei stars have a simple structure: a convective core surrounded by a radiative envelope. It is therefore worth trying to describe beta Cephei stars with composite polytropes which are useful to retrieve structure parameters from frequency spectra. We show that the structure of beta Cephei models can relatively well be described with two-zone polytropic models. However this description is not convincing to depict oscillations of beta Cephei models. [less ▲]

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