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See detailGeneration of arbitrary Dicke states in remote qubits using linear optics
Maser, A.; Thiel, C.; Schilling, U. et al

Conference (2008)

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See detailGeneration of artificial magnetic fields using dipole-dipole interactions
Cesa, Alexandre ULg; Martin, John ULg

Poster (2014, June 23)

In 1996, Lloyd [1] showed that the dynamics of complex many-body quantum systems can be efficiently simulated by quantum computers, an idea first put forward by Manin [2] and further developed by Feynman ... [more ▼]

In 1996, Lloyd [1] showed that the dynamics of complex many-body quantum systems can be efficiently simulated by quantum computers, an idea first put forward by Manin [2] and further developed by Feynman [3]. Although the first quantum computers of a few qubits have been realised experimentally [4, 5], the advent of scalable quantum computers might take another few decades. An alternative tool in the context of simulation is a highly controllable quantum system able to mimic the dynamics of other complex quantum systems, known as an analog quantum simulator. Cold neutral atoms and trapped ions have been shown to be versatile quantum simulators [6, 7] thanks to their high flexibility, controllability, and scalability. They permit one to study a wide range of problems arising from atomic physics, relativistic quantum physics, or cosmology [8]. Since neutral atoms do not carry any net charge, the simulation of electric and magnetic condensed matter phenomena, such as the spin Hall effect, seems out of reach. To overcome this apparent difficulty, the idea has been proposed to create artificial electromagnetic potentials for neutral atoms based on atom-light interaction [9– 12]. These artificial potentials act on neutral atoms as real electromagnetic potentials act on charged particles. Many works on artificial gauge potentials induced by atom-light interactions adopt a single-particle approach [12]. The predicted potentials are then supposed to be valid for a system of weakly interacting atoms. So far, the consequences of atom-atom interactions on the generation of artificial gauge fields has little been studied. The aim of this work is to study the artificial gauge fields arising from the interaction of two Rydberg atoms driven by a common laser field [13]. In this situation, we show that the combined atom-atom and atom-field interactions give rise to nonuniform, artificial gauge potentials. We identify the mechanism responsible for the emergence of these gauge potentials. Analytical expressions for the latter indicate that the strongest artificial magnetic fields are reached in the regime intermediate between the dipole blockade regime and the regime in which the atoms are sufficiently far apart such that atom-light interaction dominates over atom-atom interactions. We discuss the differences and similarities of artificial gauge fields originating from resonant dipole-dipole [14] and van der Waals [15] interactions. We also give an estimation of experimentally attainable artificial magnetic fields resulting from this mechanism and we discuss their detection through the deflection of the atomic motion. [1] S. Lloyd, Science 273, 1073 (1996). [2] Yu. I. Manin, Computable and uncomputable, Sovetskoye Radio, Moscow, 1980. [3] R. P. Feynman, Int. J. Theor. Phys. 21, 467 (1982). [4] L. DiCarlo, J. M. Chow, J. M. Gambetta, Lev S. Bishop, B. R. Johnson, D. I. Schuster, J. Majer, A. Blais, L. Frunzio, S. M. Girvin, and R. J. Schoelkopf, Nature 460, 240 (2009). [5] N. Xu, J. Zhu, D. Lu, X. Zhou, X. Peng, and J. Du, Phys. Rev. Lett. 108, 130501 (2012). [6] I. Buluta and F. Nori, Science 326, 108 (2009). [7] I. Bloch, J. Dalibard and S. Nascimbéne, Nature Physics 8, 267 (2012). [8] R. Blatt and C. F. Roos, Nature Physics 8, 277 (2012). [9] G. Juzeliunas and P. Öhberg, Phys. Rev. Lett. 93, 033602 (2004). [10] G. Juzeliunas, P. Öhberg, J. Ruseckas, and A. Klein, Phys. Rev. A 71, 053614 (2005). [11] G. Juzeliunas, J. Ruseckas, P. Öhberg, and M. Fleischhauer, Phys. Rev. A 73, 025602 (2006). [12] J. Dalibard, F. Gerbier, G. Juzeliu ̄nas, and P. Öhberg, Rev. Mod. Phys. 83, 1523 (2011). [13] A. Cesa and J. Martin, Phys. Rev. A 88,062703 (2013). [14] A. Gaëtan, Y. Miroshnychenko, T. Wilk, A. Chotia, M. Viteau, D. Comparat, P. Pillet, A. Browaeys, and P. Grangier, Nature Physics 5, 115 (2009). [15] L. Béguin, A. Vernier, R. Chicireanu, T. Lahaye, and A. Browaeys, Phys. Rev. Lett. 110, 263201 (2013). [less ▲]

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See detailGeneration of bovine multisite haplotypes using random cosmids
Steele, M.; Georges, Michel ULg

in Genomics (1991), 10

One hundred ten random cosmids were used to probe Southern blots of DNA from nine unrelated cattle digested with 12 restriction enzymes. Although only one-third of the expected fragments were explored, 85 ... [more ▼]

One hundred ten random cosmids were used to probe Southern blots of DNA from nine unrelated cattle digested with 12 restriction enzymes. Although only one-third of the expected fragments were explored, 85% of the cosmids revealed at least one polymorphism. The mean heterozygosity of the generated haplotypes was estimated at 51.9%. A surprisingly high proportion of polymorphisms (approximately 25%) was attributed to insertion-deletion events, compensating for the lower level of nucleotide diversity observed in cattle (pi approximately 0.0007) compared to that in human. The mutation rate at cytosines in the CpG dinucleotide was estimated approximately 10 times higher than that at other nucleotides. When used in linkage studies, the generated markers should cover approximately 50% of the bovine genome. [less ▲]

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See detailGeneration of camelid single-domain antibody fragments raised against proteins containing polyglutamine expansions
Pain, Coralie ULg; Scarafone, Natacha; Jaspar, Aurélie et al

Poster (2010, October 14)

Nine progressive neurodegenerative diseases are associated with the expansion of a polyglutamine (polyQ) tract above a threshold size (~ 35-45 residues) into nine different proteins [1]. These proteins ... [more ▼]

Nine progressive neurodegenerative diseases are associated with the expansion of a polyglutamine (polyQ) tract above a threshold size (~ 35-45 residues) into nine different proteins [1]. These proteins with expanded polyQ repeats have been found to form intranuclear amyloid-like aggregates, and the formation of these aggregates could play an important role in the pathogenesis [2-4]. The polyQ expansion is the only common feature among the proteins involved, suggesting it may be responsible for the aggregation phenomenon. Understanding the molecular mechanism by which the polyQ expansions promote aggregation is therefore crucial for the development of therapeutic strategies. The nine proteins associated with polyQ diseases are difficult to express recombinantly due to their big size and/or their insoluble character. In order to get further insights into the mechanism by which polyQ tracts promote aggregation, we have therefore decided to insert polyQ sequences into a well studied protein, the b-lactamase BlaP from B. licheniformis [5-6]. We have created chimeras containing 23, 30, 55, and 79 glutamines and we have investigated the effects of the insertions on the activity, the structure, the stability of BlaP as well as on its aggregating properties. Preliminary results indicate that BlaP is a good framework to study the molecular mechanism of aggregation associated with expanded polyglutamine tracts. On another hand, our previous work on the amyloidogenic variants of human lysozyme has shown that camelid single domain antibody fragments are very powerful structural probes to understand, at the molecular level, the mechanism of amyloid fibril formation [7]. Moreover, a recent study has suggested that expanded polyQ strectches adopt multiple conformations in solution that can be readily distinguished by monoclonal antibodies [8]. Altogether these results have encouraged us to generate VHHs against our different chimeras and we present here our preliminary results. References [1] Orr and Zoghbi (2007) Annu Rev Neurosci 30, 575-621. [2] DiFiglia et al. (1997) Science 277, 1990-1993. [3] Paulson HL (2000) Brain Pathol 10, 293-299. [4] Sanchez I. et al. (2003) Nature 421, 373-379. [5] Scarafone N. (2008) Mémoire de DEA en Sciences. Université de Liège. [6] Pain C. (2009) Mémoire de Master en Biochimie. Université de Liège. [7] Dumoulin et al. (2003) Nature 424, 783-788. [8] Legleiter J. et al. (2009) J Biol Chem 284, 21647-21648. [less ▲]

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See detailGeneration of closed-form models for the control of flexible mechanisms: a numerical approach
Bruls, Olivier ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

in Proc. of the 7th Int. Conf. on Motion and Vibration Control (MOVIC) (2004, August)

In robotics, most high performances control strategies require a closed-form representation of the mechanical dynamic behaviour. This is even more critical when significant flexible effects are to be ... [more ▼]

In robotics, most high performances control strategies require a closed-form representation of the mechanical dynamic behaviour. This is even more critical when significant flexible effects are to be considered in the control algorithm. This paper presents a method to build closed-form dynamic equations for flexible multibody systems in terms of minimal coordinates. Relying on the Finite Element (FE) formulation, the method is able to tackle complex topologies with closed-loops in a systematic way. The method is based on an interpolation strategy. For a number of selected points in the configuration space, a full Finite Element model is built and reduced according to a component mode synthesis. Then, a piecewise polynomial model is adjusted to match the collected data. In order to guarantee the continuity of the model, a mode tracking strategy is implemented. After the presentation of the reduction procedure and of the interpolation strategy, a four-bar mechanism is analyzed as an illustrative example. [less ▲]

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See detailGeneration of Dicke states in Distant Matter Qubits with Linear Optics
Thiel, C.; von Zanthier, J.; Bastin, Thierry ULg et al

Conference (2007)

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See detailGeneration of digital surface models and orthophotos of urban areas with IKONOS stereopairs
Devriendt, Dennis; Goossens, Rudi; Binard, Marc ULg

(2004)

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of ... [more ▼]

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of value-added products that fulfill some of the actual information needs, as expressed by Belgian authorities at the local and at the regional level. One of the technical research modules is focussing on the geometrical aspects of VHR data processing. Due to the capability of the IKONOS sensor up to an angle of 26° off-nadir, the satellite can take stereo image pairs. An IKONOS stereo pair consists of two images of the same location taken from two different perspectives on the same orbital pass. Although it is possible to obtain a stereopair from two images from different orbital passes and with a large time interval, it is proved that the stereopairs ordered from Spaceimaging or resellers gives better results (2004, Taillieu et al.). This paper describes the method applied for DSM generation from an IKONOS stereopair, over an urban area. The geometrical accuracy of the DSM is compared with the accuracy of a DSM, derived from aerial photography at scales of 1:12000 and 1:4000. The satellite-derived DSM is used for ortho-rectification of VHR imagery. The accuracy of the ortho-rectified images is compared with ortho-rectifications of the same images, based on the aerial photo DSM. [less ▲]

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See detailGeneration of infrared imagery from an aviation synthetic vision database
Bonjean, Maxime E.; Verly, Jacques ULg; Schiefele, Jeff

Conference (2005)

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See detailGeneration of Long-lived Entanglement on Demand in Remote Qubits
Schilling, U.; Thiel, C.; Bastin, Thierry ULg et al

Conference (2009)

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See detailGeneration of rapid eye movements during paradoxical sleep in humans
Peigneux, Philippe ULg; Laureys, Steven ULg; Fuchs, Sonia et al

in NeuroImage (2001), 14(3), 701-708

Although rapid eye movements (REMs) are a prominent feature of paradoxical sleep (PS), their origin and functional significance remain poorly understood in humans. In animals, including nonhuman primates ... [more ▼]

Although rapid eye movements (REMs) are a prominent feature of paradoxical sleep (PS), their origin and functional significance remain poorly understood in humans. In animals, including nonhuman primates, REMs during PS are closely related to the occurrence of the so-called PGO waves, i.e., prominent phasic activities recorded throughout the brain but predominantly and most easily in the pons (P), the lateral geniculate bodies (G), and the occipital cortex (O). Therefore, and because the evolution of species is parsimonious, a plausible hypothesis would be that during PS in humans, REMs are generated by mechanisms similar to PGO waves. Using positron emission tomography and iterative cerebral blood flow measurements by H(2)(15)O infusions, we predicted that the brain regions where the PGO waves are the most easily recorded in animals would be differentially more active in PS than in wakefulness, in relation with the density of the REM production [i.e., we looked for the condition (PS versus wakefulness) by performance (REM density) interaction]. Accordingly, we found a significant interaction effect in the right geniculate body and in the primary occipital cortex. The result supports the hypothesis of the existence of processes similar to PGO waves in humans, responsible for REM generation. The interest in the presence of PGO waves in humans is outstanding because the cellular processes involved in, or triggered by, PGO waves might favor brain plasticity during PS. [less ▲]

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See detailGeneration of spatially correlated wind histories
Denoël, Vincent ULg

in Proceedings of the first Internation Conference on Finite Element Methods (2003)

Turbulent wind is a natural and therefore random phenomenon. The analysis of flexible structures subjected to turbulent wind requires, in a finite element approach, the resolution of a system of ... [more ▼]

Turbulent wind is a natural and therefore random phenomenon. The analysis of flexible structures subjected to turbulent wind requires, in a finite element approach, the resolution of a system of stochastic differential equations. It is supposed that the characteristics of the structure are perfectly known; thus the stochastic aspect of the problem comes from the random loading only. As the turbulent wind is most commonly characterized by its frequency content, the resolution of this equation is generally performed in the frequency domain. All governing equations must therefore be linear. If this can be reasonably supposed for the structure, this hypothesis is not mathematically justified for the wind loading. When the non linear behaviour of any part of the structure has to be accounted for, the resolution in the frequency domain is not valid anymore. It is then necessary to compute, with a step-by-step dynamic analysis, the response of the structure to a series of generated wind histories. In a finite element approach, this is for example achieved thanks to Newmark’s or Wilson’s methods. Averaging across the ensemble of the computed time-varying responses allows then to recover statistical results that a stochastic analysis would provide. This analysis method is known as a stochastic Monte Carlo simulation. After having emphasised the need to represent correctly the coherence between wind pressures at different points of the structure, this paper will present a method for generating a set of correlated wind histories that must be used in a finite element analysis. Finally an example of application of the presented method will prove its efficiency. [less ▲]

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See detailGeneration of superoxide anion by mitochondria and impairment of their functions during anoxia and reoxygenation in vitro.
Du, G.; Mouithys-Mickalad, A.; Sluse, Francis ULg

in Free Radical Biology & Medicine (1998), 25

A small portion of the oxygen consumed by aerobic cells is converted to superoxide anion at the level of the mitochondrial respiratory chain. If produced in excess, this harmful radical is considered to ... [more ▼]

A small portion of the oxygen consumed by aerobic cells is converted to superoxide anion at the level of the mitochondrial respiratory chain. If produced in excess, this harmful radical is considered to impair cellular structures and functions. Damage at the level of mitochondria have been reported after ischemia and reperfusion of organs. However, the complexity of the in vivo system prevents from understanding and describing precise mechanisms and locations of mitochondrial impairment. An in vitro model of isolated-mitochondria anoxia-reoxygenation is used to investigate superoxide anion generation together with specific damage at the level of mitochondrial oxidative phosphorylation. Superoxide anion is detected by electron paramagnetic resonance spin trapping with POBN-ethanol. Mitochondrial respiratory parameters are calculated from oxygen consumption traces recorded with a Clark electrode. Respiring mitochondria produce superoxide anion in unstressed conditions, however, the production is raised during postanoxic reoxygenation. Several respiratory parameters are impaired after reoxygenation, as shown by decreases of phosphorylating and uncoupled respiration rates and of ADP/O ratio and by increase of resting respiration. Partial protection of mitochondrial function by POBN suggests that functional damage is related and secondary to superoxide anion production by the mitochondria in vitro. [less ▲]

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See detailGeneration of supporting and hair cells from progenitors isolated from a newborn mammalian organ of Corti
Malgrange, B; Belachew, S; Thiry, Marc ULg et al

Conference (2001)

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See detailGeneration of symmetric Dicke states
Thiel, C.; von Zanthier, J.; Bastin, Thierry ULg et al

Poster (2008)

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See detailGeneration of Symmetric Dicke States of Remote Qubits with Linear Optics
Thiel, C.; von Zanthier, J.; Bastin, Thierry ULg et al

in Physical Review Letters (2007), 99

We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using linear ... [more ▼]

We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using linear optical tools only. By means of a suitable multiphoton detection technique, erasing Welcher-Weg information, our proposed scheme allows the generation and measurement of an important class of entangled multiqubit states. [less ▲]

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See detailGeneration of T lymphocytes from the epithelium and stroma of squamous pre-neoplastic lesions of the uterine cervix.
Jacobs, Nathalie ULg; Giannini, Sandra ULg; Al-Saleh, Walid et al

in Journal of Immunological Methods (1999), 223(1), 123-9

In this study, we have developed a simple and efficient technique for the isolation of viable lymphocytes from the epithelium and stroma of small pre-neoplastic squamous intraepithelial lesions (SIL) of ... [more ▼]

In this study, we have developed a simple and efficient technique for the isolation of viable lymphocytes from the epithelium and stroma of small pre-neoplastic squamous intraepithelial lesions (SIL) of the uterine cervix. Following the separation of the epithelium from the stroma using dispase II, both biopsy fragments were used to generate T lymphocytes. The stroma-derived lymphocytes were obtained by collecting and culturing the cells migrating out of the biopsy in the presence of IL2 (50 U/ml). An average of 0.7 x 10(6) and 1.4 x 10(6) lymphocytes could be obtained after 20 and 30 days of culture, respectively. For the expansion of lymphocytes derived from the pre-neoplastic epithelium (SIL) it was necessary to use a combination of irradiated peripheral blood mononuclear cells (PBMC) as a feeder layer with PHA (0.1%), in addition to IL2 (50 U/ml). Interestingly, these lymphocytes could be obtained using either allogeneic or syngeneic PBMCs. With this protocol, we were able to generate up to 100 x 10(6) lymphocytes from the epithelium, the majority of which were T lymphocytes. [less ▲]

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See detailGeneration of the Cape Ghir upwelling filament: A numerical study
Troupin, Charles ULg; Mason, Evan; Beckers, Jean-Marie ULg et al

in Ocean Modelling (2012), 41

Filaments are narrow, shallow structures of cool water originating from the coast. They are typical features of the four main eastern boundary upwelling systems (EBUS). In spite of their significant ... [more ▼]

Filaments are narrow, shallow structures of cool water originating from the coast. They are typical features of the four main eastern boundary upwelling systems (EBUS). In spite of their significant biological and chemical roles, through the offshore exportation of nutrient-rich waters, the physical processes that generate them are still not completely understood. This paper is a process-oriented study of filament generation mechanisms. Our goal is twofold: firstly, to obtain a numerical solution able to well represent the characteristics of the filament off Cape Ghir (30°38'N, northwestern Africa) in the Canary EBUS and secondly, to explain its formation by a simple mechanism based on the balance of potential vorticity. The first goal is achieved by the use of the ROMS model (Regional Ocean Modeling System) in embedded domains around Cape Ghir, with a horizontal resolution going up to 1.5 km for the finest domain. The latter gets its initial and boundary conditions from a parent solution and is forced by climatological, high-resolution atmospheric fields. The modeled filaments display spatial, temporal and physical characteristics in agreement with the available in situ and satellite observations. This model solution is used as a reference to compare the results with a set of process-oriented experiments. These experiments allow us to reach the second objective. Their respective solution serves to highlight the contribution of various processes in the filament generation. Since the study is focused on general processes present under climatological forcing conditions, inter-annual forcing is not necessary. The underlying idea for the filament generation is the balance of potential vorticity in the Canary EBUS: the upwelling jet is characterized by negative relative vorticity and flows southward along a narrow band of uniform potential vorticity. In the vicinity of the cape, an injection of relative vorticity induced by the wind breaks the existing vorticity balance. The upwelling jet is prevented from continuing its way southward and has to turn offshore to follow lines of equal potential vorticity. The model results highlight the essential role of wind, associated with the particular topography (coastline and bottom) around the cape. The mechanism presented here is general and thus can be applied to other EBUS. [less ▲]

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