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 detailDynamic Effect of Solvation on the Optical Properties of a CdTe Nanocrystal
Malcioǧlu, O. B.; Raty, Jean-Yves ULg

in Advanced Optical Materials (2013), 1(3), 239-243

Changes in the optical response of a CdTe quantum dot (QD) due to dynamic and surface effects are investigated using ab initio methods. The model successfully captures experimentally reported non-linear ... [more ▼]

Changes in the optical response of a CdTe quantum dot (QD) due to dynamic and surface effects are investigated using ab initio methods. The model successfully captures experimentally reported non-linear trends in the optical spectra. The combination of ab initio molecular dynamics, time-dependent DFT, and optical spectroscopy provides a very effective method to investigate various dynamic effects on very small QDs, and to explore generalizable trends for similar structures. Using TDDFT and ab-initio molecular dynamics, a correlation is established between the time evolution of spectral features with various structural components of a ligand-stabilized CdTe quantum dot. The localization of charge oscillations due to light absorption is investigated before and after embedding the quantum dot in an explicit solvent environment. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. [less ▲]

Detailed reference viewed: 14 (1 ULg)
See detailDynamic extended equal area criterion. Part 1. Basic formulation
Xue, Yusheng; Rousseaux, Patricia ULg; Gao, Z. et al

in Proceedings of the IEEE Athens Power Tech Conference (1993)

Detailed reference viewed: 56 (4 ULg)
See detailDynamic extended equal area criterion. Part 2. Embedding fast valving and automatic voltage regulation
Xue, Yusheng; Zhang, Y.; Gao, Z. et al

in Procedings of the IEEE Athens Power Tech Conference (1993)

Detailed reference viewed: 20 (0 ULg)
Full Text
Peer Reviewed
See detailDynamic generalized linear models and repeated measurements
Lindsey, James ULg; Lambert, Philippe ULg

in Journal of Statistical Planning & Inference (1995), 47

The dynamic generalized linear model for non-normal data is extended for use in repeated measurements, when series of observations are available for more than one individual. Examples are given for count ... [more ▼]

The dynamic generalized linear model for non-normal data is extended for use in repeated measurements, when series of observations are available for more than one individual. Examples are given for count and duration data. [less ▲]

Detailed reference viewed: 41 (2 ULg)
Full Text
Peer Reviewed
See detailA Dynamic Graph Model of Endochondral Ossification can assess the Importance of Biological Actors in Differentiation
Kerkhofs, Johan ULg; Van Oosterwyck, Hans; Geris, Liesbet ULg

Conference (2012, September 18)

Cell-based tissue engineering constructs are a promising avenue for the treatment of long bone defects since they provide the primordial ingredients for bone regeneration. The construct provides the ... [more ▼]

Cell-based tissue engineering constructs are a promising avenue for the treatment of long bone defects since they provide the primordial ingredients for bone regeneration. The construct provides the appropriate micro-environment through the carrier, cells to form tissue and chemical cues to kick start the natural bone forming process. Clearly this approach will benefit from a more comprehensive appreciation of how cell populations and the microenvironment provided by the carrier can impact on bone formation in all its complexities. A cornucopia of studies of developmental biology have revealed many biological actors that together form a central network that orchestrates cell behaviour during this process and assures its robustness. This knowledge can be brought to bear specifically in the form of a mathematical model of endochondral ossification, the dominant type of ossification. This model can facilitate the understanding of how growth factors and transcription factors influence cell fate decisions and consequently answer the question whether they can boost bone healing. The model formalism accommodates the qualitative information that is typically available in developmental studies. The network comprises 46 nodes and 161 interactions, shown to be important in endochondral ossification. To simulate network dynamics in discrete time the normalized value of each gene is determined by additive functions where all interactions are assumed to be equally powerful. Furthermore, each species is represented by a fast variable (activity level, as determined by post translation modifications) which is assumed to be in equilibrium with a slow variable (mRNA) at all times. Through a Monte Carlo approach the importance of each node in the stability of chondrocytic phenotypes (proliferating, hypertrophic) is assessed. The hypertrophic state, driven by Runx2, is more stable than the proliferating chondrocyte. This higher stability seems to be conferred by faster reactions that favor the hypertrophic phenotype. In addition, the results point out that some transcription factors are necessary for the induction of a certain phenotype, whereas other transcription factors are required to maintain the phenotype, but are not necessary capable of inducing it. Overall, the model allows the importance of several important factors in the fate decision of mesenchymal cells to be quantitatively assessed based mainly on topological information. [less ▲]

Detailed reference viewed: 19 (1 ULg)
Full Text
Peer Reviewed
See detailDynamic Hedge Fund Style Analysis with Errors-in-Variables
Bodson, Laurent ULg

Conference (2009, May)

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to ... [more ▼]

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to identify the more appropriate benchmarks for the analyzed fund return. Then, we compute their corresponding higher moment estimated errors-in-variables, i.e. the measurement error series introducing the (cross) moments of order three and four. We adjust the selected benchmarks by subtracting their higher moments estimated EIV from the initial return series, to obtain an estimate of the true uncontaminated benchmarks. We finally run the Kalman filter on these adjusted regressors. Analyzing EDHEC alternative indexes styles, we show that this technique improves the factor loadings and permits to identify more precisely the return sources of the considered hedge fund strategy. [less ▲]

Detailed reference viewed: 83 (24 ULg)
Full Text
Peer Reviewed
See detailDynamic Hedge Fund Style Analysis with Errors-in-Variables
Bodson, Laurent ULg; Hübner, Georges ULg; Coën, Alain

Conference (2008, July)

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to ... [more ▼]

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to identify the more appropriate benchmarks for the analyzed fund return. Then, we compute their corresponding higher moment estimated errors-in-variables, i.e. the measurement error series introducing the (cross) moments of order three and four. We adjust the selected benchmarks by subtracting their higher moments estimated EIV from the initial return series, to obtain an estimate of the true uncontaminated benchmarks. We finally run the Kalman filter on these adjusted regressors. Analyzing EDHEC alternative indexes styles, we show that this technique improves the factor loadings and permits to identify more precisely the return sources of the considered hedge fund strategy. [less ▲]

Detailed reference viewed: 75 (41 ULg)
Full Text
Peer Reviewed
See detailDynamic Hedge Fund Style Analysis with Errors-in-Variables
Bodson, Laurent ULg; Hübner, Georges ULg; Coën, Alain

Conference (2008, April)

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to ... [more ▼]

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to identify the more appropriate benchmarks for the analyzed fund return. Then, we compute their corresponding higher moment estimated errors-in-variables, i.e. the measurement error series introducing the (cross) moments of order three and four. We adjust the selected benchmarks by subtracting their higher moments estimated EIV from the initial return series, to obtain an estimate of the true uncontaminated benchmarks. We finally run the Kalman filter on these adjusted regressors. Analyzing EDHEC alternative indexes styles, we show that this technique improves the factor loadings and permits to identify more precisely the return sources of the considered hedge fund strategy. [less ▲]

Detailed reference viewed: 56 (16 ULg)
Full Text
Peer Reviewed
See detailDynamic Hedge Fund Style Analysis with Errors-in-Variables
Bodson, Laurent ULg; Hübner, Georges ULg; Coën, Alain

Conference (2008, June)

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to ... [more ▼]

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to identify the more appropriate benchmarks for the analyzed fund return. Then, we compute their corresponding higher moment estimated errors-in-variables, i.e. the measurement error series introducing the (cross) moments of order three and four. We adjust the selected benchmarks by subtracting their higher moments estimated EIV from the initial return series, to obtain an estimate of the true uncontaminated benchmarks. We finally run the Kalman filter on these adjusted regressors. Analyzing EDHEC alternative indexes styles, we show that this technique improves the factor loadings and permits to identify more precisely the return sources of the considered hedge fund strategy. [less ▲]

Detailed reference viewed: 55 (21 ULg)
Full Text
Peer Reviewed
See detailDynamic Hedge Fund Style Analysis with Errors-in-Variables
Bodson, Laurent ULg; Coën, Alain ULg; Hübner, Georges ULg

Conference (2008, July)

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to ... [more ▼]

This paper revisits the traditional return-based style analysis (RBSA) in presence of time-varying exposures and errors-in-variables (EIV). We first apply a selection algorithm using the Kalman filter to identify the more appropriate benchmarks for the analyzed fund return. Then, we compute their corresponding higher moment estimated errors-in-variables, i.e. the measurement error series introducing the (cross) moments of order three and four. We adjust the selected benchmarks by subtracting their higher moments estimated EIV from the initial return series, to obtain an estimate of the true uncontaminated benchmarks. We finally run the Kalman filter on these adjusted regressors. Analyzing EDHEC alternative indexes styles, we show that this technique improves the factor loadings and permits to identify more precisely the return sources of the considered hedge fund strategy. [less ▲]

Detailed reference viewed: 62 (15 ULg)
Full Text
Peer Reviewed
See detailDynamic Hedge Fund Style Analysis with Errors-in-Variables
Bodson, Laurent ULg; Coën, Alain; Hübner, Georges ULg

in Journal of Financial Research (2010), 33(3), 201-221

We revisit the traditional return-based style analysis in the presence of time varying exposures and errors-in-variables (EIV). We apply a benchmark selection algorithm using the Kalman filter and compute ... [more ▼]

We revisit the traditional return-based style analysis in the presence of time varying exposures and errors-in-variables (EIV). We apply a benchmark selection algorithm using the Kalman filter and compute the estimated EIV of the selected benchmarks. We adjust them by subtracting their EIV from the initial return series to obtain an estimate of the true uncontaminated benchmarks. Finally, we run the Kalman filter on these adjusted regressors. Analyzing EDHEC alternative index styles, we show that this technique improves the factor loadings and allows more precise identification of the return sources of the considered hedge fund strategy. [less ▲]

Detailed reference viewed: 59 (14 ULg)
Full Text
Peer Reviewed
See detailDynamic holographic interferometry development for dilatometry measurement of composites under vacuum-thermal conditions
Thizy, Cédric ULg; Barbier, Christian ULg; Tychon, Isabelle ULg et al

in Dirckx, J.; Buytaert, J. (Eds.) Proceedings of the 4th International Conference on Optical Measurement and Techniques for Systems & Structures (OPTIMESS 2009) (2009)

The Centre Spatial de Liège develops since 1993 holographic interferometry techniques and instruments based on photorefractive crystals for high resolution measurement of structures deformation, mainly ... [more ▼]

The Centre Spatial de Liège develops since 1993 holographic interferometry techniques and instruments based on photorefractive crystals for high resolution measurement of structures deformation, mainly for aerospace applications. In this paper we present the early results of development of a holographic technique and facility for deformation and expansion measurement of aerospace composites components. Here the holographic technique consists in using several illumination beams for retrieving different components of the displacement vector. In our case the components and structures to be measured in the future will undergo temperatures excursions up to 150°C typically. Since holographic techniques are sensitive to air turbulences, it is necessary to place the samples in a vacuum chamber. We will present some early examples of measurements with this facility, obtained for temperatures excursions ranged between ambient and 29°C as first steps before going further to higher temperatures excursions. [less ▲]

Detailed reference viewed: 23 (6 ULg)
See detailDynamic holographic interferometry for dilatation measurements in vacuum-thermal conditions
Thizy, Cédric ULg; Barbier, Christian ULg; Barzin, Pascal ULg et al

in Lehmann, Peter (Ed.) Proc. SPIE Vol 7398 on Optical Measurement Systems for Industrial Inspection VI (2009, June)

Detailed reference viewed: 44 (16 ULg)
Full Text
See detailDynamic holographic interferometry with photorefractive crystals : review of applications and advanced techniques
Georges, Marc ULg; Thizy, Cédric ULg; Scauflaire, W. et al

in Gastinger, K.; Lokberg, O.; Winther, S. (Eds.) Speckle Metrology 2003 (2003, June)

We will present the basic properties of photorefractive crystals and show how they can be used efficiently in holographic interferometry experiments. We then will present some holographic systems and ... [more ▼]

We will present the basic properties of photorefractive crystals and show how they can be used efficiently in holographic interferometry experiments. We then will present some holographic systems and their numerous applications. With continuous illumination, we will show classical non destructive testing (defect detection), displacement metrology, vibration mode shape visualization, as well as a study for the use of photorefractive crystals in microgravity monitoring of fluid (FSL experiment aboard the International Space Station). With pulsed illumination we will present the possibilities of the photorefractive crystals in vibration measurement (and will introduce the ongoing EC-funded PHIFE research project). The purpose of the paper is to unmystify photorefractive crystals and to show that they could be a good alternative to traditional speckle-based techniques for highly demanding applications. For that we will highlight the highest resolution achieved as well as the high temporal dynamics of the holographic recording [less ▲]

Detailed reference viewed: 11 (0 ULg)
Full Text
See detailDynamic holographic interferometry: Devices and applications
Lemaire, Philippe ULg; Georges, Marc ULg

in Günther, P.; Huignard, J.-P. (Eds.) Photorefractive Materials and Their Applications 3. Applications (2007)

Detailed reference viewed: 13 (2 ULg)
Full Text
See detailDynamic holography for fringerprints detection
Lemaire, Philippe; Georges, Marc ULg

Conference (2004, January)

Fingerprint detection method is generally based on optical contrast technique. We present a special case of holographic interferometry use, that envisages fingerprint visualisation on base of their relief ... [more ▼]

Fingerprint detection method is generally based on optical contrast technique. We present a special case of holographic interferometry use, that envisages fingerprint visualisation on base of their relief. Background of the algorithm is first presented and discussed. We finish by practical application. [less ▲]

Detailed reference viewed: 21 (0 ULg)
See detailDynamic holography for the space qualification of large reflectors
Thizy, Cédric ULg; Stockman, Yvan ULg; Doyle, D. et al

in Optical Fabrication, Testing, and Metrology II (2005, October)

The next generation of infrared - sub mm space telescopes requires reflectors with large dimensions, high quality and, according to weight issues, are based on composite or new materials technology. The ... [more ▼]

The next generation of infrared - sub mm space telescopes requires reflectors with large dimensions, high quality and, according to weight issues, are based on composite or new materials technology. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of these reflectors shape and antenna structures and to verify their performance under simulated space conditions (vacuum, low-high temperatures). A holographic camera for the verification and validation of this type of reflector in a space environment is presented. A diffuser is implemented to measure the deformations of reflective surfaces in a more flexible way. The system has been made compatible with the vacuum conditions. Some elements of the holographic camera (camera lenses, CCD, crystal, optical fibre) have been adapted and tested under vacuum. The metrological certification of the whole system is realised by the measurement of a parabolic CFRP reflector with a 1.1 meter diameter. The results are compared to the one achieved with a high spatial resolution IR interferometer on the same reflector in laboratory conditions and under thermal vacuum conditions. This later test consists in measuring the deformations of the reflector between an initial state at a selected temperature and a final state at another temperature. The comparison between the high spatial resolution IR interferometer and this dynamic holographic method showed very good qualitative and quantitative agreement between the techniques, thus verifying the potential of this new Holographic approach. [less ▲]

Detailed reference viewed: 56 (3 ULg)
Full Text
Peer Reviewed
See detailA dynamic in vivo model of epithelial-to-mesenchymal transitions in circulating tumor cells and metastases of breast cancer.
Bonnomet, Arnaud; Syne, Laïdya ULg; Brysse, Anne ULg et al

in Oncogene (2012), 31(33), 3741-53

Epithelial-to-mesenchymal transition (EMT) processes endow epithelial cells with enhanced migratory/invasive properties and are therefore likely to contribute to tumor invasion and metastatic spread ... [more ▼]

Epithelial-to-mesenchymal transition (EMT) processes endow epithelial cells with enhanced migratory/invasive properties and are therefore likely to contribute to tumor invasion and metastatic spread. Because of the difficulty in following EMT processes in human tumors, we have developed and characterized an animal model with transplantable human breast tumor cells (MDA-MB-468) uniquely showing spontaneous EMT events to occur. Using vimentin as a marker of EMT, heterogeneity was revealed in the primary MDA-MB-468 xenografts with vimentin-negative and vimentin-positive areas, as also observed on clinical human invasive breast tumor specimens. Reverse transcriptase-PCR after microdissection of these populations from the xenografts revealed EMT traits in the vimentin-positive zones characterized by enhanced 'mesenchymal gene' expression (Snail, Slug and fibroblast-specific protein-1) and diminished expression of epithelial molecules (E-cadherin, ZO-3 and JAM-A). Circulating tumor cells (CTCs) were detected in the blood as soon as 8 days after s.c. injection, and lung metastases developed in all animals injected as examined by in vivo imaging analyses and histology. High levels of vimentin RNA were detected in CTCs by reverse transcriptase-quantitative PCR as well as, to a lesser extent, Snail and Slug RNA. Von Willebrand Factor/vimentin double immunostainings further showed that tumor cells in vascular tumoral emboli all expressed vimentin. Tumoral emboli in the lungs also expressed vimentin whereas macrometastases displayed heterogenous vimentin expression, as seen in the primary xenografts. In conclusion, our data uniquely demonstrate in an in vivo context that EMT occurs in the primary tumors, and associates with an enhanced ability to intravasate and generate CTCs. They further suggest that mesenchymal-to-epithelial phenomena occur in secondary organs, facilitating the metastatic growth [less ▲]

Detailed reference viewed: 48 (7 ULg)