Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailLarge Changes In The Crac Segment Of Gp41 Of Hiv Do Not Destroy Fusion Activity If The Segment Interacts With Cholesterol
Vishwanathan, Sa.; Thomas, Annick ULiege; Brasseur, Robert ULiege et al

in Biochemistry (2008), 47(45),

The membrane-proximal external region (MPER) of the gp41 fusion protein of HIV is highly conserved among isolates of this virus and is considered a target for vaccine development. This region also appears ... [more ▼]

The membrane-proximal external region (MPER) of the gp41 fusion protein of HIV is highly conserved among isolates of this virus and is considered a target for vaccine development. This region also appears to play a role in membrane fusion as well as localization of the virus to cholesterol-rich domains in membranes. The carboxyl terminus of MPER has the sequence LWYIK and appears to have an important role in cholesterol interactions. We have tested how amino acid substitutions that would affect the conformational flexibility of this segment could alter its interaction with cholesterol. We studied a family of peptides (all peptides as N-acetyl-peptide amides) with P, G, or A substituting for W and I of the LWYIK sequence. The peptide having the greatest effect on cholesterol distribution in membranes was the most flexible one, LGYGK. The corresponding mutation in gp41 resulted in a protein retaining 72% of the fusion activity of the wild-type protein. Two other peptides were synthesized, also containing two Gly residues, GWGIK and LWGIG, and did not have the ability to sequester cholesterol as efficiently as LGYGK did. Making the corresponding mutants of gp41 showed that these other two double Gly substitutions resulted in proteins that were much less fusogenic, although they were equally well expressed at the cell surface. The study demonstrates that drastic changes can be made in the LWYIK segment with the retention of a significant fraction of the fusogenic activity, as long as the mutant proteins interact with cholesterol. [less ▲]

Detailed reference viewed: 12 (0 ULiège)
Full Text
Peer Reviewed
See detailLarge colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago
El Albani, Abder; Bengtson, Stefan; Canfield, Donald et al

in Nature (2010), 466

Detailed reference viewed: 90 (22 ULiège)
Full Text
Peer Reviewed
See detailLarge current enhancement in n-MOSFETs with strained Si on insulator
Mantl, S.; Buca, D.; Zhao, Q. et al

in International Semiconductor Device Research Symposium, 2007 (2007)

As scaling of the critical transistor dimensions below 65 nm has been slowed down, the implementation of novel materials, especially high mobility channel materials is most attractive to boost the ... [more ▼]

As scaling of the critical transistor dimensions below 65 nm has been slowed down, the implementation of novel materials, especially high mobility channel materials is most attractive to boost the transistor performance. Applying strain to silicon has become a successful route. The electron mobility can be enhanced by biaxial strain introduced into Si by epitaxial growth of Si on a strain relaxed SiGe layer or by so called process induced methods applied directly on transistor level. The combination of strained Si and SOI is particularly promising due to the combination of the enhanced mobilities and the inherent advantages of SOI. First long channel n-MOSFETs with gate lengths of 5 to 50 mum and a 6.6 nm thick SiO2 gate dielectric were fabricated. For comparison, devices on unstrained SOI were made. The transfer characteristics of a fully depleted sSOI-MOSFET with a gate length of 5 mum and a gate width of 20 mum indicating an inverse sub-threshold slope of 75mV/dec. [less ▲]

Detailed reference viewed: 17 (1 ULiège)
Full Text
Peer Reviewed
See detailLarge deformation FEMLIP drained analysis of a vertical cut
Cuomo, Sabatino; Prime, Noémie ULiege; Iannone, Anna et al

in Acta Geotecnica (2012)

Detailed reference viewed: 30 (1 ULiège)
Full Text
Peer Reviewed
See detailLarge deployable telescopes—also for lm-wavelengths?
Baier, Horst; Datashvili, Leri; Endler, Stephan et al

in CEAS Space Journal (2013), 5(3-4), 117-124

New demands for space and earth observations drive the need for large apertures of 10 m and higher in telescopes. This requires new types of alternative lightweight and deployable primary reflector or ... [more ▼]

New demands for space and earth observations drive the need for large apertures of 10 m and higher in telescopes. This requires new types of alternative lightweight and deployable primary reflector or lens concepts with aerial densities of\3 kg/m2. Some syntheses between optical and especially mechanical and material aspects for large planar photon sieves and non-imaging telescopes are discussed. Focus is put on large planar and highly perforated membranes for photon sieves and shell-membrane type deployable (parabolic) reflectors, respectively. The reflecting surface of the latter is composed of specific C-fiber reinforces silicone (CFRS) material. In addition to possible shape control, emphasis is also given to reflective coating of CFRS. Engineering challenges requiring future activities are identified. [less ▲]

Detailed reference viewed: 16 (0 ULiège)
Full Text
Peer Reviewed
See detailLarge deviation spectra based on wavelet leaders
Bastin, Françoise ULiege; Esser, Céline ULiege; Jaffard, Stéphane ULiege

in Revista Matemática Iberoamericana (2016), 32(3), 859-890

We introduce a new multifractal formalism, based on distributions of wavelet leaders, which allows to detect non-concave and decreasing multifractal spectra, and we investigate the properties of the ... [more ▼]

We introduce a new multifractal formalism, based on distributions of wavelet leaders, which allows to detect non-concave and decreasing multifractal spectra, and we investigate the properties of the associated function spaces. [less ▲]

Detailed reference viewed: 157 (27 ULiège)
Full Text
See detailLarge displacement formulations for elastic bodies
Fraeijs de Veubeke, Baudouin ULiege

Report (1969)

Detailed reference viewed: 23 (2 ULiège)
Full Text
See detailLarge Dynamic Range Co-Phasing System Development for Segmented Telescope Mirrors
Simar, Juan Felipe ULiege

Poster (2011, December 02)

Detailed reference viewed: 72 (25 ULiège)
Full Text
Peer Reviewed
See detailLarge earthquakes Cycles in Lake Sediments along the North Anatolian Fault, Turkey
Boës, X.; Moran, S. B.; King, J. et al

in Journal of Paleolimnology (2009), (10.1007/s10933-009-9376-x),

In 1999, the large surface-rupturing earth- quakes of Izmit and Duzce completed a 60-year cycle that included a westward migration of nine consecutive large earthquake failures ([50 km surface rupture ... [more ▼]

In 1999, the large surface-rupturing earth- quakes of Izmit and Duzce completed a 60-year cycle that included a westward migration of nine consecutive large earthquake failures ([50 km surface rupture), which started with the 1939 Erzincan earthquake in eastern Turkey. In this study, we focused on seismic cycles and seismic risk predictability along the North Anatolian Fault (NAF). Toward the west end of the NAF (26°E–32°E, i.e. Bolu), large earthquake fre- quency is measured from either historic earthquake catalogs, or geologic records from isolated outcrops and marine sediment cores from the Marmara Sea. In comparison, the eastern part of the NAF zone (32°E– 42°E) is less well documented by palaeo-seismologic archives. Thus, the sediment records of lake basins located on the eastern NAF zone constitute a unique opportunity for testing a new palaeo-seismologic approach. To this end, we used a diverse array of complementary methods involving: (1) a 600-km transect of fault-related lakes, (2) sedimentologic observations on cores from six lakes, and (3) a comparison between records of catastrophic sediment transfers in lakes (i.e. radionuclide chronomarkers and erosion tracers) and historic earthquake reports. Our study indicates that lakes along the NAF are sensitive geologic recorders of large surface-rupturing earth- quakes (surface-wave magnitude (Ms) C 6.9); smaller intensities are not recorded. The most responsive lake systems exhibit increases in sediment accumulation by a factor of [40 for a [3-m strike-slip displacement (Ms C 7). However, based on results from the 1939 Erzincan earthquake (Ms = 7.8) chronostratigraphic marker, large surface-rupturing earthquakes are detected only by certain lake records and not by others. Matching multiple lake records along the NAF pro- vides information both on the location of a surface rupture of a paleo-earthquake as well as its magnitude. Finally, the shallow lake basins along the NAF could potentially document cycles of large seismic events for at least the late Holocene. [less ▲]

Detailed reference viewed: 58 (7 ULiège)
Full Text
Peer Reviewed
See detailLarge elasto-optic effect and reversible electrochromism in multiferroic BiFeO3
Sando, D.; Yang, Yurong; Bousquet, Eric ULiege et al

in Nature Communications (2016), 7

The control of optical fields is usually achieved through the electro-optic or acousto-optic effect in single-crystal ferroelectric or polar compounds such as LiNbO3 or quartz. In recent years, tremendous ... [more ▼]

The control of optical fields is usually achieved through the electro-optic or acousto-optic effect in single-crystal ferroelectric or polar compounds such as LiNbO3 or quartz. In recent years, tremendous progress has been made in ferroelectric oxide thin film technology—a field which is now a strong driving force in areas such as electronics, spintronics and photovoltaics. Here, we apply epitaxial strain engineering to tune the optical response of BiFeO3 thin films, and find a very large variation of the optical index with strain, corresponding to an effective elasto-optic coefficient larger than that of quartz. We observe a concomitant strain-driven variation in light absorption—reminiscent of piezochromism—which we show can be manipulated by an electric field. This constitutes an electrochromic effect that is reversible, remanent and not driven by defects. These findings broaden the potential of multiferroics towards photonics and thin film acousto-optic devices, and suggest exciting device opportunities arising from the coupling of ferroic, piezoelectric and optical responses. [less ▲]

Detailed reference viewed: 28 (12 ULiège)
Full Text
Peer Reviewed
See detailLarge Excess of Heavy Nitrogen in Both Hydrogen Cyanide and Cyanogen from Comet 17P/Holmes
Bockelée-Morvan, D.; Biver, N.; Jehin, Emmanuel ULiege et al

in Astrophysical Journal (2008), 679(Letters), 49-52

From millimeter and optical observations of the Jupiter-family comet 17P/Holmes performed soon after its huge outburst of 2007 October 24, we derive [SUP]14[/SUP]N/[SUP]15[/SUP]N = 139 +/- 26 in HCN and ... [more ▼]

From millimeter and optical observations of the Jupiter-family comet 17P/Holmes performed soon after its huge outburst of 2007 October 24, we derive [SUP]14[/SUP]N/[SUP]15[/SUP]N = 139 +/- 26 in HCN and [SUP]14[/SUP]N/[SUP]15[/SUP]N = 165 +/- 40 in CN, establishing that HCN has the same nonterrestrial isotopic composition as CN. The same conclusion is obtained for the long-period comet C/1995 O1 (Hale-Bopp) after a reanalysis of previously published measurements. These results are compatible with HCN being the prime parent of CN in cometary atmospheres. The [SUP]15[/SUP]N excess relative to the Earth's atmospheric value indicates that N-bearing volatiles in the solar nebula underwent important N isotopic fractionation at some stage of solar system formation. HCN molecules never isotopically equilibrated with the main nitrogen reservoir in the solar nebula before being incorporated in Oort Cloud and Kuiper Belt comets. The [SUP]12[/SUP]C/[SUP]13[/SUP]C ratios in HCN and CN are measured to be consistent with the terrestrial value. [less ▲]

Detailed reference viewed: 45 (5 ULiège)
See detailLarge group teaching: the distance learning solution?
Pasleau, Françoise ULiege; Doseray, Patrick; Fairon, Nicolas ULiege et al

Poster (2005, June)

Problem-based learning has been introduced at the University of Liège for four years now. The medical library was committed with the organisation of different activities (60 hours/2 years), starting with ... [more ▼]

Problem-based learning has been introduced at the University of Liège for four years now. The medical library was committed with the organisation of different activities (60 hours/2 years), starting with the control of basic computer litteracy, continuing with an analysis of the structure of the different document types used for scientific communication as well as the discovery of both traditional and electronic medical libraries, to end with guidelines for information retrieval. Such courses requested new approaches and several difficulties had to be taken into consideration including : 1. The transfer of skills rather than kowledge. Some theoretical bases have to be taught before practicing. But the students mostly need to be challenged with different situations requesting different approaches of litterature searching. 2. The course is given before the students feel the need of it. The librarians enconter the students during the first semester of the second year before the students are asked to search the medical litterature to build their own knowledge about clinical matters. 3. The absence of motivation. Second year medical students are focused on major courses in basic and preclinical sciences. 4. Large group teaching (n ≥ 300). All the sections of the medical Faculty are concerned. 5. Inadequate logistic support. Small sized computer rooms do not allow the organization of very many parallel hand-on sessions. 6. Insufficient teaching staffs. Distance learning tools were used to develope online activities complementary to face to face teaching. They are focused on practice. Links to the theory are provided but only when they are indispensable. Many quizzes are also proposed in order to trigger critical mind and auto-evaluation. By January 2005, a first cycle will be completed from the beginning of the course to the final examination. We plan to survey students from every section in order to evaluate the impact of this new teaching strategy. Their observations will be reported as well as our conclusions and suggestions for possible improvements. [less ▲]

Detailed reference viewed: 91 (5 ULiège)
See detailLarge Leptonic Mixing and Quasi-degenerate Neutrinos
Wegman Ostrosky, Daniel ULiege

Conference (2014)

Detailed reference viewed: 9 (0 ULiège)
Full Text
Peer Reviewed
See detailLarge Margin Classification with the Progressive Hedging Algorithm
Defourny, Boris ULiege; Wehenkel, Louis ULiege

Conference (2009, December)

Several learning algorithms in classification and structured prediction are formulated as large scale optimization problems. We show that a generic iterative reformulation and resolving strategy based on ... [more ▼]

Several learning algorithms in classification and structured prediction are formulated as large scale optimization problems. We show that a generic iterative reformulation and resolving strategy based on the progressive hedging algorithm from stochastic programming results in a highly parallel algorithm when applied to the large margin classification problem with nonlinear kernels. We also underline promising aspects of the available analysis of progressive hedging strategies. [less ▲]

Detailed reference viewed: 62 (4 ULiège)
Full Text
Peer Reviewed
See detailLarge N(c) QCD versus quark model
Semay, Claude; Buisseret, Fabien; Stancu, Floarea ULiege et al

in Few-Body Systems (2008), 44

Detailed reference viewed: 22 (4 ULiège)
Full Text
See detailLarge Nc baryons and Regge trajectories
Matagne, Nicolas; Stancu, Floarea ULiege

in Bled Workshops in Physics (2013, November), 14(1), 37-42

The mixed symmetric positive and negative parity baryons are described in a similar way in the $1/N_c$ expansion method of QCD by using a procedure where the permutation symmetry is incorporated exactly ... [more ▼]

The mixed symmetric positive and negative parity baryons are described in a similar way in the $1/N_c$ expansion method of QCD by using a procedure where the permutation symmetry is incorporated exactly. This allows to express the mass formula in terms of a small number of linearly independent operators. We show that the leading term follows a different Regge trajectory from that found for symmetric states, when plotted as a function of the band number $N$. [less ▲]

Detailed reference viewed: 33 (6 ULiège)
Full Text
Peer Reviewed
See detailLarge neighborhood search for multi-trip vehicle routing
François, Véronique ULiege; Arda, Yasemin ULiege; Crama, Yves ULiege et al

in European Journal of Operational Research (2016), 255(2), 422-441

We consider the multi-trip vehicle routing problem, in which each vehicle can perform several routes during the same working shift to serve a set of customers. The problem arises when customers are close ... [more ▼]

We consider the multi-trip vehicle routing problem, in which each vehicle can perform several routes during the same working shift to serve a set of customers. The problem arises when customers are close to each other or when their demands are large. A common approach consists of solving this problem by combining vehicle routing heuristics with bin packing routines in order to assign routes to vehicles. We compare this approach with a heuristic that makes use of specific operators designed to tackle the routing and the assignment aspects of the problem simultaneously. Two large neighborhood search heuristics are proposed to perform the comparison. We provide insights into the configuration of the proposed algorithms by analyzing the behavior of several of their components. In particular, we question the impact of the roulette wheel mechanism. We also observe that guiding the search with an objective function designed for the multi-trip case is crucial even when exploring the solution space of the vehicle routing problem. We provide several best known solutions for benchmark instances. [less ▲]

Detailed reference viewed: 89 (27 ULiège)
Full Text
See detailLarge neighborhood search for multi-trip vehicle routing
François, Véronique ULiege; Arda, Yasemin ULiege; Crama, Yves ULiege et al

E-print/Working paper (2015)

We consider two large neighborhood search approaches for the multi-trip vehicle routing problem, where each vehicle can perform several routes during the working shift to serve a set of customers. The ... [more ▼]

We consider two large neighborhood search approaches for the multi-trip vehicle routing problem, where each vehicle can perform several routes during the working shift to serve a set of customers. The problem specifically arises when customers are close to each other and/or when the demands are large. A common approach in the literature consists in solving this problem by mixing vehicle routing heuristics with bin packing routines to assign routes to vehicles. We compare this approach with the use of specific operators designed to tackle the routing and the assignment aspects of the problem simultaneously. We provide several best known solutions for benchmark instances. At the end of the work, we give insights about the proposed algorithm configurations by analyzing the behavior of several method components. [less ▲]

Detailed reference viewed: 136 (19 ULiège)
Full Text
Peer Reviewed
See detailLARGE ORGANIC-WALLED MICROFOSSILS IN MESOARCHEAN SHALLOW-MARINE SILICICLASTIC DEPOSITS
Javaux, Emmanuelle ULiege; Marshall, Craig; Bekker, Andrey

Conference (2010, June)

Detailed reference viewed: 29 (2 ULiège)
Full Text
Peer Reviewed
See detailA large oxygen-dominated core from the seismic cartography of a pulsating white dwarf
Giammichele, Noemi; Charpinet, Stéphane; Fontaine, Gilles et al

in Nature (2018), 554

White-dwarf stars are the end product of stellar evolution for most stars in the Universe1. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution2,3. Moreover ... [more ▼]

White-dwarf stars are the end product of stellar evolution for most stars in the Universe1. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution2,3. Moreover, they are important chronometers for dating galactic stellar populations, and their mergers with other white dwarfs now appear to be responsible for producing the type Ia supernovae that are used as standard cosmological candles4. However, the internal structure of white-dwarf stars—in particular their oxygen content and the stratification of their cores—is still poorly known, because of remaining uncertainties in the physics involved in stellar modelling codes5,6. Here we report a measurement of the radial chemical stratification (of oxygen, carbon and helium) in the hydrogen- deficient white-dwarf star KIC08626021 (J192904.6+444708), independently of stellar-evolution calculations. We use archival data7,8 coupled with asteroseismic sounding techniques9,10 to determine the internal constitution of this star. We find that the oxygen content and extent of its core exceed the predictions of existing models of stellar evolution. The central homogeneous core has a mass of 0.45 solar masses, and is composed of about 86 per cent oxygen by mass. These values are respectively 40 per cent and 15 per cent greater than those expected from typical white-dwarf models. These findings challenge present theories of stellar evolution and their constitutive physics, and open up an avenue for calibrating white-dwarf cosmochronology11. [less ▲]

Detailed reference viewed: 80 (4 ULiège)