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See detailColonization of a new habitat by copepods: An in situ experiment
Mascart, Thibaud ULiege; Lepoint, Gilles ULiege; Biondo, Renzo ULiege et al

Conference (2014, December 12)

Colonization of new habitats by a biological community is conspicuous and this dynamic process is one of the architectural forces of the biogeographical distribution we know today. Within the meiofauna ... [more ▼]

Colonization of new habitats by a biological community is conspicuous and this dynamic process is one of the architectural forces of the biogeographical distribution we know today. Within the meiofauna (<1mm), copepods (Crustacea) have successfully adapted to nearly every ecosystem and heir colonization power of permanent habitats is therefore well-established. However, few studies tackled the colonization of new naturally occurring provisional habitats, which are of ecological interest since they are rich in organic material, structurally complex and devoted of native fauna. Hence, the present study investigated the copepod colonization of provisional macrophytodetritus (mainly composed of senescent leaves and drift macroalgae) accumulated on bare sand patches inside a Mediterranean Posidonia oceanica seagrass meadow. General motive of colonization such as food and shelter are well-defined. However, little is known regarding the mode of the colonization and source pool of the associated colonists. Here, an in situ experiment was deployed in order to understand the mode of copepod’s colonization to fauna deprived macrophytodetritus. The objectives were: (1) assessing the adjacent colonist’s source pool (i.e. sediment, water column or P. oceanica canopy), (2) investigating the speed of settlement and (3) quantifying the species composition of the colonizing copepods. In summary: (1) species from every source pool actively colonized the macrophytodetritus through the water column and through the sediment-macrophytodetritus interface. (2) The initial settlement occurred within the first 24 hours. (3) The species composition showed to be different than the source’s composition. After 24h, the composition was similar to 45% of the P. oceanica, 28% of the water column and 25% of the sediments. After 96h, the composition was similar to 24% of the P. oceanica, 13% of the water column and 10% of the sediments. Indicating an evolution towards a macrophytodetritus copepod specific community composed of a mixture of the adjacent habitats first colonizers. [less ▲]

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See detailColonne lithologique du sondage de Latour (494 m): une coupe de référence pour le Secondaire de la Gaume
Boulvain, Frédéric ULiege; Monteyne, R.

in Professional paper Belgian geological survey (1993), 267

Detailed reference viewed: 86 (3 ULiège)
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See detailColonoscopie virtuelle par scanner
HOCK, DANIELLE; MATERNE, R.; OUHADI, ROXANNE et al

in Colonoscopie virtuelle par scanner. EMC Radiologie et imagerie médicale : Abdominale - Digestive (2011)

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See detailColonoscopie virtuelle par scanner. Encyclopédie Médico-Chirurgicale, Gastro-entérologie
HOCK, D.; MATERNE, R.; OUHADI, Roxanne et al

in Colonoscopie virtuelle par scanner. Encyclopédie Médico-Chirurgicale, Gastro-entérologie (2013)

Detailed reference viewed: 17 (4 ULiège)
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See detailColony collapse disorder: a descriptive study.
Vanengelsdorp, Dennis; Evans, Jay D; Saegerman, Claude ULiege et al

in PLoS ONE (2009), 4(8), 6481

BACKGROUND: Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this ... [more ▼]

BACKGROUND: Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. METHODS AND PRINCIPAL FINDINGS: Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. CONCLUSIONS/SIGNIFICANCE: This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted. [less ▲]

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See detailColor in the urban environment: A user-oriented protocol for chromatic characterization and the development of a parametric typology
Nguyen, Ngoc Luan ULiege; Teller, Jacques ULiege

in Color Research and Application (2016)

This article presents a user-oriented protocol that can be used to characterize chromatic attributes of an urban area. A need for both affordable and reliable assessment method of color has been observed ... [more ▼]

This article presents a user-oriented protocol that can be used to characterize chromatic attributes of an urban area. A need for both affordable and reliable assessment method of color has been observed in the field of urban design. The challenge is to provide statistical answers to these two questions: how is color organized, how does it develop its own structure in the city? The main purpose of the research is hence to investigate mean color types within the city via the implementation of a characterization tool; an urban area of the four main classes (historic center, periurban housing districts, working-class neighborhoods, and commercial zones) being characterized by a specific color palette, or a layout of specific color types. The developed instrumentation allows the assessment of the homogeneous and consistent features of an urban district. Their characterization protocol was tested through an application to several streets of the city of Liège (Belgium). [less ▲]

Detailed reference viewed: 119 (35 ULiège)
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See detail“Color is a kind of holy substance for me”: analytical study of the Sam Francis’ palette from the 1940’s to the 1990’s
Defeyt, Catherine ULiege; Mazurek, Joy; Zebala, Aneta et al

Poster (2016, March)

The Sam Francis’s colors, literally described as vivid, saturated, pure, vibrant intense and rich, largely contribute to the unique character of his work. This idiosyncrasy explains the interest in ... [more ▼]

The Sam Francis’s colors, literally described as vivid, saturated, pure, vibrant intense and rich, largely contribute to the unique character of his work. This idiosyncrasy explains the interest in conducting an extended study on the Francis’ painting materials through analytical techniques. On the other hand, many Francis’ paintings display colored surfaces that exhibit bronzing, fluorescent or opalescent effects. As a consequence, retouching paint losses from Sam Francis works may become a challenging task for the involved conservators, the degree of the color matching required in the imitative technique being particularly difficult to attain, in the presence of such surfaces. Furthermore, the attained degree of the color match has to be conserved in all conditions of illumination and observation. The use of pigments chemically similar to the original ones is often necessary for matching highly chromatic pigments. Though, many modern synthetic organic pigments (SOPs) possess high color strength. That is why the characterization of the Francis palette would provide helpful information to the conservators, which have to deal with this type of issue. The upcoming Getty publication Sam Francis: The Artist’s Materials, planned for 2016, offered the opportunity for in-depth analyses of hundreds paint samples. Almost three hundreds of paint fragments supplied by the Sam Francis Foundation have been investigated at the GCI laboratory, by using three complementary analytical techniques, Py-GC-MS, Raman and FTIR spectroscopies. The Raman spectroscopy is one of the most efficient techniques for identifying SOPs in paint systems, while the Py-GC-MS and FTIR methods provide essential information concerning the binding media. The analyzed paint fragments were sampled from twenty-nine canvases and works on paper, made between 1946 and 1992. Although, primary established in Southern California, Sam Francis spent numerous long journeys in different places around the world, including Paris, Bern, Mexico City, New York and Tokyo. However, the material study has outlined the uninterrupted use of` certain classes of SOPs in specific colors. For example, copper phthalocyanine (CuPc) pigments were systematically detected in the blue and green samples, while azo pigments have been identified in most of the yellow areas sampled from post 1940s works. Regardless of the support and the paint technique, the Francis’ blues primary contain Ultramarine and/or CuPc blue pigments. And, it has been shown that the bronzing blue surfaces noticed for some of the investigated artworks correspond to PB15-based paint films. The present study has also underlined the recurrent use of perinone orange and dioxazine violet in fluorescent orange and purple area. Despite the early introduction of SOPs, on the Francis’ palette, the works dating from the 1940’s remained mainly composed of traditional inorganic pigments, for instance lead white and red, chrome yellow, viridian and iron oxides. Interestingly, various binding media, i.e. Shellac gum, modified and unmodified oils, PVA, alkyd resins and acrylic copolymers have been identified. Actually, the investigated samples have pointed out the frequent combination of more than three types of binders on a same painting. Through the identification of the various SOPs used by Francis over fifty years, this research provide helpful information for selecting the most appropriate retouching pigments. [less ▲]

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See detailThe color ratio-intensity relation in the Jovian aurora: Hubble observations of auroral components
Gérard, Jean-Claude ULiege; Bonfond, Bertrand ULiege; Grodent, Denis ULiege et al

in Planetary and Space Science (2016), 131

Spectral observations made with the long slit of the Space Telescope Imaging Spectrograph (STIS) on board Hubble have been used to construct spectral maps of the FUV Jovian aurora. They reveal that the ... [more ▼]

Spectral observations made with the long slit of the Space Telescope Imaging Spectrograph (STIS) on board Hubble have been used to construct spectral maps of the FUV Jovian aurora. They reveal that the amount of absorption by overlying methane shows significant spatial variations. In this report, we examine the relationship between the auroral brightness of the unabsorbed H2 emission that is proportional to the precipitated electron energy flux, and the ultraviolet color ratio, a proxy of the mean electron energy. We find that it varies significantly between the different components of the aurora and in the polar region. Although no global dependence can be found, we show that the two quantities are better organized in some auroral components such as regions of the main aurororal emission. By contrast, the dependence of the electron characteristic energy in high-latitude and diffuse aurora regions on the auroral energy input is generally more scattered. We conclude that the various auroral components are associated with different electron acceleration processes, some of which are not governed by a simple relation linking the value of a field-aligned acceleration potential with the parallel currents flowing from the ionosphere. [less ▲]

Detailed reference viewed: 31 (12 ULiège)
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See detailColor terms in medieval artists’ recipe books : diversity and variability. The puzzling case of ‘Paris Red’
Neven, Sylvie ULiege

Conference (2013)

Occurrences of historical color terms can be found in several old written sources and, notably, in medieval artists’ recipe books. In parallel to the physical descriptions of pigments and colorants, these ... [more ▼]

Occurrences of historical color terms can be found in several old written sources and, notably, in medieval artists’ recipe books. In parallel to the physical descriptions of pigments and colorants, these writings deliver information about their optical characteristics, conservation, (in)compatibility with other sorts of materials, and ageing properties. Examination conducted within a corpus of more than 400 recipe books, dating from 1300 to 1650 and produced in Northern Europe, has shed light on the diversity of color denominations and the several ways of designating a coloring material, such as pigments and colorants. Color terms used in artists’ recipe books may have had various meanings and correspond to different hues, subtances or qualities. Moreover, the concept or the material designated by a color term may change, not just in time and space, but from one recipe to another even if they derive from the same source. Looking through a large number of instructions dedicated to colors, it is possible to propose some categories for describing the different sorts of nomenclature and their nature, and it is also possible to suggest the range of pigments and colorants that one word could refer to. Variety and importance given to color names can also be put in relation with the importance and the symbolic value accorded to a coloring agent or a color. This paper will focuss on the various appellations of red color. In particular, it will examine in depth the puzzling name “Paris Red”. [less ▲]

Detailed reference viewed: 36 (3 ULiège)
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See detailLa coloration des tissus chargés de vitellus
Damas, Hubert ULiege

in Archives de Biologie (1946), 56

Detailed reference viewed: 12 (1 ULiège)
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See detailI colori di Place de la République (Wölfflin, Floch e la fotografia)
Beyaert-Geslin, Anne; Dondero, Maria Giulia ULiege

in Dondero, Maria Giulia; Basso Fossali, Pierluigi (Eds.) Semiotica della fotografia. Investigazioni teoriche e pratiche di analisi (2006)

Detailed reference viewed: 23 (0 ULiège)
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See detailA Colorimetric Assay for the Simultaneous Measurement of Plasminogen Activators and Plasminogen Activator Inhibitors in Serum-Free Conditioned Media from Cultured Cells
Leprince, Pierre ULiege; Rogister, Bernard ULiege; Moonen, Gustave ULiege

in Analytical Biochemistry (1989), 177(2), 341-6

The coupled photometric assay for plasminogen activator reported by Coleman and Green (1981) Methods in Enzymology (Lorand, L., Ed.), Vol. 80, pp. 408-414, Academic Press, San Diego, CA) has been adapted ... [more ▼]

The coupled photometric assay for plasminogen activator reported by Coleman and Green (1981) Methods in Enzymology (Lorand, L., Ed.), Vol. 80, pp. 408-414, Academic Press, San Diego, CA) has been adapted for use with 96-well plates and an automatic microplates spectrophotometer. The assay allows the discrimination between tissue-type and urokinase-type plasminogen activators in cell culture-conditioned media. It provides a level of detection of these enzymes in the range 10(-17) to 10(-13) mol (determined using purified human plasminogen activators), uses no radioisotopes, and is faster and more economical than similar assays using specific peptide substrates for plasminogen activators. Levels of free plasminogen activator inhibitor activity can be simultaneously measured on the same samples by a simple adaptation of the assay. This method allows an easy treatment of the data by interfacing with a computer and should thus be useful when large numbers of samples are assayed. [less ▲]

Detailed reference viewed: 32 (9 ULiège)
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See detailA colorimetric method for the determination of lipase activity in soil
Margesin, R.; Feller, Georges ULiege; Hammerle, M. et al

in Biotechnology Letters (2002), 24(1), 27-33

A colorimetric method for the determination of lipase activity in soil has been developed. Using p-nitrophenyl butyrate as substrate, soil samples are incubated at 30 degreesC and pH 7.25 for 10 min ... [more ▼]

A colorimetric method for the determination of lipase activity in soil has been developed. Using p-nitrophenyl butyrate as substrate, soil samples are incubated at 30 degreesC and pH 7.25 for 10 min. After cooling on ice and centrifugation, the released p-nitrophenol is determined at 400 nm. To allow for the adsorption of p-nitrophenol onto soil, a calibration curve is prepared in the presence of soil. [less ▲]

Detailed reference viewed: 199 (1 ULiège)
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See detailColoring Graphs Using Two Colors while Avoiding Monochromatic Cycles
Talla Nobibon, Fabrice ULiege; Hurkens, Cor A. J.; Leus, Roel et al

in INFORMS Journal on Computing (2011)

We consider the problem of deciding whether a given directed graph can be vertex partitioned into two acyclic subgraphs. Applications of this problem include testing rationality of collective consumption ... [more ▼]

We consider the problem of deciding whether a given directed graph can be vertex partitioned into two acyclic subgraphs. Applications of this problem include testing rationality of collective consumption behavior, a subject in microeconomics. We prove that the problem is NP-complete even for oriented graphs and argue that the existence of a constant-factor approximation algorithm is unlikely for an optimization version that maximizes the number of vertices that can be colored using two colors while avoiding monochromatic cycles. We present three exact algorithms—namely, an integer-programming algorithm based on cycle identification, a backtracking algorithm, and a branch-and-check algorithm. We compare these three algorithms both on real-life instances and on randomly generated graphs. We find that for the latter set of graphs, every algorithm solves instances of considerable size within a few seconds; however, the CPU time of the integer-programming algorithm increases with the number of vertices in the graph more clearly than the CPU time of the two other procedures. For real-life instances, the integer-programming algorithm solves the largest instance in about a half hour, whereas the branch-and-check algorithm takes approximately 10 minutes and the backtracking algorithm less than 5 minutes. Finally, for every algorithm, we also study empirically the transition from a high to a low probability of a YES answer as a function of the number of arcs divided by the number of vertices. [less ▲]

Detailed reference viewed: 44 (1 ULiège)
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See detailColoring of the infinite grid
Vandomme, Elise ULiege; Gravier, Sylvain

Poster (2012, May 23)

We present a method that links (r,a,b)-codes in the infinite grid and particular colorings of weighted cycles, called constant 2-labellings.

Detailed reference viewed: 37 (13 ULiège)
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See detailColoss Working Group 1: monitoring and diagnosis.
Nguyen, Bach Kim ULiege; Van der zee, Romée; Vejsnaes, Flemming et al

in Journal of Apicultural Research (2010), 49(1), 97-99

Detailed reference viewed: 106 (18 ULiège)
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See detailColossal positive magnetoresistance in a doped nearly magnetic semiconductor
Hu, Rongwei; Thomas, K. J.; Lee, Y. et al

in Physical Review B (2008), 77(8),

We report on a positive colossal magnetoresistance (MR) induced by metallization of FeSb2, a nearly magnetic or "Kondo" semiconductor with 3d ions. We discuss the contribution of orbital MR and quantum ... [more ▼]

We report on a positive colossal magnetoresistance (MR) induced by metallization of FeSb2, a nearly magnetic or "Kondo" semiconductor with 3d ions. We discuss the contribution of orbital MR and quantum interference to the enhanced magnetic field response of electrical resistivity. [less ▲]

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See detailColosses et perspective: de la prise en considération de la parallaxe dans la statuaire pharaonique de grandes dimensions au Nouvel Empire
Laboury, Dimitri ULiege

in Revue d'Egyptologie (2008), 59

The deformation which affects the physiognomy of colossal sculptures of the New Kingdom suggests that Ancient Egyptian Art could have taken into account the parallax effects or distortions due to ... [more ▼]

The deformation which affects the physiognomy of colossal sculptures of the New Kingdom suggests that Ancient Egyptian Art could have taken into account the parallax effects or distortions due to perspective. This question and its methodological and theoretical implications are investigated, with a special focus on the colossi of Amenhotep IV from Karnak. [less ▲]

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See detailLe colostrum bovin : "une solution pour réduire les effets négatifs du sevrage"
Boudry, Christelle ULiege

Article for general public (2008)

Detailed reference viewed: 31 (8 ULiège)