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Peer Reviewed
See detailCharacterization of YKL165c a new essential gene of the yeast Saccharomyces cerevisiae.
Delbecq, Xavier; Godrie, Thérèse ULg; Portetelle, Daniel ULg et al

in Archives Internationales de Physiologie et de Biochimie (1999), 107

Detailed reference viewed: 5 (1 ULg)
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See detailCharacterization of YKL165c a new essential gene of the yeast Saccharomyces cerevisiae.
Delbecq, X.; Godrie, Thérèse ULg; Portetelle, Daniel ULg et al

in Current Genetics (1999), 35

Detailed reference viewed: 8 (3 ULg)
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See detailCharacterization study of Halaf ceramic production at Tell Amarna (Euphrates Valley, Syria)
Clop Garcia, X.; Alvarez Perez, A.; Hatert, Frédéric ULg

in Tunca, Önhan; Molist, Miquel (Eds.) Tell Amarna (Syrie) – La période de Halaf (2004)

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See detailCharacterization, dynamics and trophic ecology of macrofauna associated to seagrass macrophytodetritus accumulations (Calvi Bay, Mediterranean Sea)
Remy, François ULg

Doctoral thesis (2016)

Posidonia oceanica meadows are a major coastal Mediterranean ecosystem. Although highly productive this Mediterranean marine flower plant is not much consumed by herbivore organisms. During autumnal ... [more ▼]

Posidonia oceanica meadows are a major coastal Mediterranean ecosystem. Although highly productive this Mediterranean marine flower plant is not much consumed by herbivore organisms. During autumnal senescence, most (up to 90%) of the foliar primary production of P. oceanica ends in the “detrital compartment”. These dead leaves, also called “macrophytodetritus”, begin to degrade immediately inside the meadow, but a large amount will be rapidly exported to adjacent unvegetated accumulation zones, such as bare sand patches. Associated to drift macroalgae, living detached P. oceanica shoots, micro-organisms and fine sediment, these macrophytoderitus form what we call “exported P. oceanica litter”. This exported litter is a highly dynamic habitat for a whole community of invertebrates: meiofauna (38µm < size < 500µm) and macrofauna (size ≥ 500µm) on which we focused on. This dynamic nature of exported litter could play a major structuring role in terms of abundance, diversity and trophic ecology of this vagile macrofauna community at a seasonal, annual or spatial scale, but also during stochastic, brief and very strong perturbations: resource pulses. In this context, this PhD Thesis had 7 main objectives: i. Characterize for the first time exhaustively the macrofauna community. ii. Evaluate the spatiotemporal changes occurring at two different time scales in the detritus themselves and in the macrofauna community. iii. Relating these variations with measured environmental parameters. iv. Experimentally demonstrate the stratification occurring in a stable P. oceanica litter accumulation and the impact of this stratification on environmental conditions and on the macrofauna. v. Experimentally demonstrate the impact of resource pulses on the exported P. oceanica litter macrofauna community. vi. Unravel for the first time the global P. oceanica litter macrofauna food web using gut contents examinations and stable isotopes (C and N). vii. Evaluate the spatiotemporal changes of diet preferences of this community and determine if the observed changes are really synonym of true diet changes. This PhD Thesis demonstrated that exported P. oceanica litter was mainly composed of dead P. oceanica leaves (70-80%). It followed the natural annual cycle of P. oceanica and presented a maximum abundance in autumn just after leaves senescence. Measured environmental parameters also showed important variations linked to different factors such as force and direction of the wind, litter abundance and probably temperature. The continuous presence of the vagile macrofauna community throughout the year was demonstrated as well. This community was composed of 115 species and largely dominated by arthropods (77%), followed by annelids (12%) and mollusks (7%), while other taxa were much more anecdotal. Even if diversity is quite important, only a few species dominate largely the community. Indeed, 19 species represent more than 90% of the total abundance. One species to keep in mind: Gammarella fucicola, the most typical dominant and abundant amphipod species, representing 40-50% of the total abundance. In addition to this general pattern, litter vagile macrofauna presented important seasonal and annual variations. In the case of several species, these variations could be linked to some measured environmental parameters, but we had to recognize that most species did not seem to be influenced by environmental parameters measured during this PhD. However, oxygen concentration was the most important environmental parameter, potentially influencing 7 of the 19 most dominant and abundant species. The experimentally demonstrated physico-chemical stratification occurring inside litter accumulations was strongly related to this oxygen parameter. Indeed we demonstrated that several species were distributed in the different layers of a litter accumulation according to oxygen concentration and to a lesser extent, to nutrients concentration (mostly NH4). Besides, smaller time scale sampling allowed the identification of several stormy events corresponding to the definition of resource pulses. These pulses were demonstrated to play a potentially important role on the structure of the macrofauna community, favoring importantly the detritivore species and hypoxia tolerant species. It was also demonstrated that resource pulses could induce diet switching increasing the consumption of dead P. oceanica leaves just after the events, potentially increasing the litter decomposition by the macrofauna. The trophic web described in this PhD Thesis was composed of several trophic levels, from the primary herbivore/detritivore consumer, to second order carnivore predators. Different dietary preferences were highlighted, but major information was that dead P. oceanica leaves were ingested by a majority (85%) of the sampled species. Moreover, stable isotope analysis confirmed that P. oceanica litter was assimilated by most primary consumers and this “detrital signal” could be identified to the upper trophic levels, which is an argument in favor of the importance of macrofauna as major dead P. oceanica leaves decomposers. This also highlighted their potential role in terms of organic matter transfer from the P. oceanica meadow itself to the Mediterranean coastal food webs. Seasonal variations were observed in terms of trophic niches, and SIAR mixing model confirmed that this variability was sometimes caused by real diet modifications, potentially linked to the variable availability of food sources. This PhD Thesis, combining standardized sampling at two different time scales, trophic web analysis (gut contents and stable isotopes) and original experimentation allowed us to describe a diverse and abundant macrofauna community associated to P. oceanica exported litter, its temporal variations, potential responses to resource pulses as well as the link existing between some species and measured environmental parameters. This PhD also described the food web of this community and demonstrated the importance of dead P. oceanica leaves as food source for many invertebrates composing this community. These invertebrates thus seemed to play an important role in both litter decomposition and organic matter flux from the P. oceanica meadow to the Mediterranean coastal food webs. [less ▲]

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See detailCharacterizations by automorphism groups of some rank 3 buildings - I. Some properties of half strongly-transitive triangle buildings
Van Maldeghem, H.; Van Steen, Kristel ULg

in Geometriae Dedicata (1998), 73(2), 119-142

In a sequence of papers, we will show that the existence of a (half) strongly-transitive automorphism group acting on a locally finite triangle building Delta forces Delta to be one of the examples ... [more ▼]

In a sequence of papers, we will show that the existence of a (half) strongly-transitive automorphism group acting on a locally finite triangle building Delta forces Delta to be one of the examples arising from PSL3(K) for a locally finite local skewfield K. Furthermore, we introduce some Moufang-like conditions in affine buildings of rank 3, and characterize those examples arising from algebraic,classical or mixed type groups over a local field. In particular, we characterize the p-adic-like affine rank 3 buildings by a certain p-adic Moufang condition, and show that such a condition has zero probability to survive in hyperbolic rank 3 buildings. This shows that a construction of hyperbolic buildings as analogues of p-adic affine buildings is very unlikely to exist. Mathematics Subject Classifications (1991): 51E24, 51C05. [less ▲]

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See detailCharacterizations by automorphism groups of some rank 3 buildings - II: A half strongly-transitive locally finite triangle building is a Bruhat-Tits building
Van Maldeghem, H.; Van Steen, Kristel ULg

in Geometriae Dedicata (1999), 74(2), 113-133

We complete the proof of the fact that every locally finite triangle building Delta with a half strongly-transitive automorphism group G (e.g., this happens when Delta is defined via a (B, N)-pair in G ... [more ▼]

We complete the proof of the fact that every locally finite triangle building Delta with a half strongly-transitive automorphism group G (e.g., this happens when Delta is defined via a (B, N)-pair in G) is a Bruhat-Tits building associated with a classical linear group over a locally finite local skewfield. [less ▲]

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See detailCharacterizations by automorphism groups of some rank 3 buildings - IV: Hyperbolic p-adic Moufang buildings of rank 3
Van Maldeghem, H.; Van Steen, Kristel ULg

in Geometriae Dedicata (1999), 75(2), 115-122

In this paper, we introduce the p-adic Moufang condition for hyperbolic buildings of rank 3. It is the most obvious and simplest generalization of the p-adic Moufang condition for affine buildings ... [more ▼]

In this paper, we introduce the p-adic Moufang condition for hyperbolic buildings of rank 3. It is the most obvious and simplest generalization of the p-adic Moufang condition for affine buildings, introduced in Part III of this sequence of papers. We show that p is very restricted, which confirms (but does not prove) the conjecture that no p-adic analogue is possible for the construction of Moufang (hyperbolic) buildings by Ronan and Tits. [less ▲]

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See detailCharacterizations by automorphism groups of some rank 3 buildings, III. Moufang-like conditions
Van Steen, Kristel ULg

in Geometriae Dedicata (1999), 74(3), 225-240

In this paper, we introduce the root-Moufang condition and the p-adic Moufang condition. We show that affine buildings of type (A) over tilde(2) satisfying the root-Moufang condition are Bruhat-Tits ... [more ▼]

In this paper, we introduce the root-Moufang condition and the p-adic Moufang condition. We show that affine buildings of type (A) over tilde(2) satisfying the root-Moufang condition are Bruhat-Tits buildings. Also, every rank 3 affine building satisfying the p-adic Moufang condition is a Bruhat-Tits building. We motivate the introduction of the new conditions by showing that all Bruhat-Tits (A) over tilde(2)-buildings satisfy the root-Moufang condition, and that the (A) over tilde(2)-buildings over a p-adic field also satisfy the p-adic Moufang condition. Another application of the p-adic Moufang condition is given in Part IV of this paper. [less ▲]

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See detailCharacterizations of the elements of generalized Hölder-Zygmund spaces by means of their representation
Kreit, Damien ULg; Nicolay, Samuel ULg

in Journal of Approximation Theory (2013), 172

We give three characterizations of the elements of generalized Hölder-Zygmund spaces. The first one, based on the Littlewood-Paley decomposition is already known, but the proof given here is much simpler ... [more ▼]

We give three characterizations of the elements of generalized Hölder-Zygmund spaces. The first one, based on the Littlewood-Paley decomposition is already known, but the proof given here is much simpler. The second one, based on the wavelet decompositions generalizes a result obtained by Jaffard and Meyer. The third one uses generalized interpolation spaces. These results naturally extend the ones holding for the classical Hölder-Zygmund spaces. The manuscript has been accepted for publication in Journal of Approximation Theory. [less ▲]

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See detailCharacterizing activity sequences using Profile Hidden Markov Models
Liu, Feng; Janssens, Davy; Cui, JianXun et al

in Expert Systems with Applications (2015), 42(13), 57055722

In literature, activity sequences, generated from activity-travel diaries, have been analyzed and classified into clusters based on the composition and ordering of the activities using Sequence Alignment ... [more ▼]

In literature, activity sequences, generated from activity-travel diaries, have been analyzed and classified into clusters based on the composition and ordering of the activities using Sequence Alignment Methods (SAM). However, using these methods, only the frequent activities in each cluster are extracted and qualitatively described; the infrequent activities and their related travel episodes are disregarded. Thus, to quantify the occurrence probabilities of all the daily activities as well as their sequential orders, we develop a novel process to build multiple alignments of the sequences and subsequently derive profile Hidden Markov Models (pHMMs). This process consists of 4 major steps. First, activity sequences are clustered based on a pre-defined scheme. The frequent activities along with their sequential orders are then identified in each cluster, and they are subsequently used as a template to guide the construction of a multiple alignment of the cluster of sequences. Finally, a pHMM is employed to convert the multiple alignment into a position-specific scoring system, representing the probability of each frequent activity at each important position of the alignment as well as the probabilities of both insertion and deletion of infrequent activities. By applying the derived pHMMs to a set of activity-travel diaries collected in Belgium as well as a group of mobile phone call location data recorded in Switzerland, the potential and effectiveness of the models in capturing the sequential features of each cluster and distinguishing them from those of other clusters, are demonstrated. The proposed method can also be utilized to improve activity-based transportation model validation and travel survey designs. Furthermore, it offers a wide application in characterizing a group of any related sequences, particularly sequences varying in length and with a high frequency of short sequences that are typically present in human behavior. [less ▲]

Detailed reference viewed: 50 (6 ULg)
See detailCharacterizing human decomposition odour: an application of TD-GCxGC-TOFMS
Stadler, S; Stefanuto, Pierre-Hugues ULg; Brokl, Michal ULg et al

Conference (2013, January)

Detailed reference viewed: 25 (2 ULg)
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See detailCharacterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars
Choi, J.-Y.; Shin, I.-G.; Park, S.-Y. et al

in Astrophysical Journal (2012), 751

We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176 ... [more ▼]

We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of θ[SUB]E[/SUB] ~ 0.08 mas combined with the short timescale of t [SUB]E[/SUB] ~ 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of ~0.84 M [SUB]&sun;[/SUB] is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio. [less ▲]

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See detailCharacterizing Low-mass Binaries from Observation of Long-timescale Caustic-crossing Gravitational Microlensing Events
Shin, I.-G.; Han, C.; Choi, J.-Y. et al

in Astrophysical Journal (2012), 755

Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of ... [more ▼]

Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of two binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43 M [SUB]&sun;[/SUB] and 0.39 M [SUB]&sun;[/SUB] for MOA-2011-BLG-090 and 0.57 M [SUB]&sun;[/SUB] and 0.17 M [SUB]&sun;[/SUB] for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future. [less ▲]

Detailed reference viewed: 42 (5 ULg)
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See detailCharacterizing of protein dataset with GO ontology
Dmitrieva, Joelia Borisnova; Florea, B; Li, N et al

Poster (2012, September 09)

Detailed reference viewed: 15 (6 ULg)
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See detailCharacterizing Simpler recognizable sets of integers
Rigo, Michel ULg

in Studia Logica (2004), 76

For a given numeration system U, a set X of integers is said to be U-star-free if the language of the normalized U-representations of the elements in X is star-free. Adapting a result of McNaughton and ... [more ▼]

For a given numeration system U, a set X of integers is said to be U-star-free if the language of the normalized U-representations of the elements in X is star-free. Adapting a result of McNaughton and Papert, we give a first-order logical characterization of these sets for various numeration systems including integer base systems and the Fibonacci system. For k-ary systems, the problem of the base dependence of this property is also studied. Finally, the case of k-adic systems is developed. [less ▲]

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See detailCharacterizing simpler recognizable sets of integers
Rigo, Michel ULg

in Lecture Notes in Computer Science (2002), 2420

For the k-ary numeration system, we characterize the sets of integers such that the corresponding representations make up a star-free regular language. This result can be transposed to some linear ... [more ▼]

For the k-ary numeration system, we characterize the sets of integers such that the corresponding representations make up a star-free regular language. This result can be transposed to some linear numeration systems built upon a Pisot number like the Fibonacci system and also to k-adic numeration systems. Moreover we study the problem of the base dependence of this property and obtain results which are related to Cobham's Theorem. [less ▲]

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See detailCharacterizing the morphology of suburban settlements: a method based on a semi-automatic classification of building clusters
de Smet, Fabian; Teller, Jacques ULg

in Landscape Research (2016), 41(1), 113-130

Urban sprawl is transforming our landscapes and rural areas at a spectacular pace. Measuring the strength of the phenomenon and proposing dynamic ways to delineate suburban areas have been the object of ... [more ▼]

Urban sprawl is transforming our landscapes and rural areas at a spectacular pace. Measuring the strength of the phenomenon and proposing dynamic ways to delineate suburban areas have been the object of much debate amongst scientists. The present article takes the view that, beyond measuring and delineating suburban areas, more efforts should be directed to qualifying the morphology of built settlements within these areas. Therefore it proposes a method based on a semi-automatic classification system of building clusters, designed to describe and interpret the phenomenon from a morphological perspective. This method is based on a combination of field surveys with numerical analyses of digital land cadastre maps. The application of this classification system to the suburban area around Liege reveals that, far from developing in a complete indifference of local conditions, contemporary suburban settlements are influenced by landscape structures inherited from the past. [less ▲]

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See detailCharacterizing the operability limits of the HyShot II scramjet through RANS simulations
Emory, Michael; Terrapon, Vincent ULg; Pecnik, René et al

in 17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 2011, Vol. 2; No AIAA 2011-2282 (2011, April)

Experimental and flight data for hypersonic air-breathing vehicles are both difficult and extremely expensive to obtain, motivating the use of computational tools to enhance our understanding of the ... [more ▼]

Experimental and flight data for hypersonic air-breathing vehicles are both difficult and extremely expensive to obtain, motivating the use of computational tools to enhance our understanding of the complex physics involved. One of the major difficulties in simulating this regime is the interaction between combustion and turbulence, both of which are intrinsically complex processes. This work represents a first attempt at addressing assumptions introduced by physical models representing the turbulent reacting flow on the resulting predictions of the scramjet performance. A combustion model for high-speed flows is introduced and tested for the HyShot II vehicle. A reduced order chemistry model is then derived to investigate the effect of certain chemistry modeling assumptions within the combustion model. These models are used to investigate the unstart of the engine due to thermal choking by increasing the fuel flow rate. It is shown that an abrupt change occurs where a normal shock forms and moves upstream accompanied by a large region of subsonic flow. Additionally scalar metrics are described which are used as early indicators of unstart, to formulate safe operating limits for the scramjet engine. [less ▲]

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See detailCharaktères and voces magicae in the Greek and Latin Iatromagical Papyri
de Haro Sanchez, Magali ULg

Scientific conference (2010, December 08)

Detailed reference viewed: 29 (0 ULg)