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  • Closed Access English
    Authors: 
    Bernard Klonjkowski; Dieter Klein; Sandra Galea; Francoise Gavard; Martine Monteil; Lidia Duarte; Annie Fournier; Sophie Sayon; Kamila Górna; Reinhard Ertl; +4 more
    Publisher: HAL CCSD
    Country: France

    International audience; The evaluation of vaccine strategies in animal models is essential for the development of a vaccine against HIV. In efficacy trials conducted in non-human primate models of AIDS, vaccines based on adenoviruses compared favourably with other vaccine vectors. To determine whether this strategy could be transposed to another animal model, and by extension, to humans, we have evaluated the efficacy of adenoviral vectors in a natural model of AIDS, infection of the cat by the feline immunodeficiency virus (FIV). Recombinant canine adenoviruses expressing the envelope glycoproteins or the Gag protein of a primary strain of FIV were constructed. Three groups of six cats were immunised twice with vectors expressing FIV antigens or with a vector expressing an irrelevant antigen, green fluorescent protein, by intramuscular and subcutaneous routes. Humoral responses were elicited against the transgene product in 6/6, 3/6 and 0/6 cats after immunisation against green fluorescent protein, Gag or the envelope glycoproteins, respectively. Six weeks after the second administration, cats were challenged by the intraperitoneal route with the homologous strain, and viral burden in plasma was followed by quantitative RT-PCR. Immunisation with FIV antigens did not afford protection. Rather, viral RNA was detected at earlier time points in cats immunised against Gag than in cats immunised with a vector expressing an irrelevant antigen. Such immune-mediated enhancement did not appear to have a long-range impact on viral set point or inversion of the CD4(+)/CD8(+) ratio. Thus, in the feline AIDS model pre-existing immunity against a viral antigen exacerbated acute phase infection.

  • Publication . Article . Other literature type . Preprint . Conference object . 2005
    Open Access English
    Authors: 
    Boris Adamczewski; Yann Bugeaud;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Diophantine approximation... (M 822)

    Let $\mathbf{k}$ be an arbitrary field. For any fixed badly approximable power series $\Theta$ in $\mathbf{k}((X^{-1}))$, we give an explicit construction of continuum many badly approximable power series $\Phi$ for which the pair $(\Theta, \Phi)$ satisfies the Littlewood conjecture. We further discuss the Littlewood conjecture for pairs of algebraic power series.

  • Publication . Preprint . Article . Conference object . 2018
    Open Access English
    Authors: 
    Moser, Daniel; Abele, Hartmut; Bosina, Joachim; Fillunger, Harald; Soldner, Torsten; Wang, Xiangzun; Zmeskal, Johann; Konrad, Gertrud;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Particles and Interaction... (W 1252)

    The beta decay of the free neutron provides several probes to test the Standard Model of particle physics as well as to search for extensions thereof. Hence, multiple experiments investigating the decay have already been performed, are under way or are being prepared. These measure the mean lifetime, angular correlation coefficients or various spectra of the charged decay products (proton and electron). NoMoS, the Neutron decay prOducts MOmentum Spectrometer, presents a novel method of momentum spectroscopy: it utilizes the $R \times B$ drift effect to disperse charged particles dependent on their momentum in an uniformly curved magnetic field. This spectrometer is designed to precisely measure momentum spectra and angular correlation coefficients in free neutron beta decay to test the Standard Model and to search for new physics beyond. With NoMoS, we aim to measure inter alia the electron-antineutrino correlation coefficient $a$ and the Fierz interference term $b$ with an ultimate precision of $\Delta a/a < 0.3\%$ and $\Delta b < 10^{-3}$ respectively. In this paper, we present the measurement principles, discuss measurement uncertainties and systematics, and give a status update. Comment: 7 pages, 4 figures, accepted to the Proceedings of the International Workshop on Particle Physics at Neutron Sources PPNS 2018, Grenoble, France, May 24-26, 2018

  • Publication . Conference object . Part of book or chapter of book . Book . 2004
    Open Access English
    Authors: 
    Jakob Puchinger; Günther R. Raidl;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Combining Memetic Algorit... (P 16263)

    International audience; We consider the 3-stage two-dimensional bin packing problem , which occurs in real-world problems such as glass cutting. For it, we present a new integer linear programming formulation and a branch and price algorithm. Column generation is performed by applying either a greedy heuristic or an Evolutionary Algorithm (EA). Computational experiments show the benefits of the EA-based approach. The higher computational effort of the EA pays off in terms of better final solutions; furthermore more instances can be solved to provable optimality.

  • Publication . Other literature type . Article . Conference object . 2004
    Open Access English
    Authors: 
    Bernard Jouffrey; Peter Schattschneider; Cécile Hébert;
    Publisher: HAL CCSD
    Countries: Switzerland, France

    Abstract We resolve the long-standing mysterious discrepancy between the experimental magic angle in EELS— ∼ 2 ϑ E —and the quantum mechanical prediction of ∼ 4 ϑ E . A relativistic approach surpassing the usually applied kinematic correction yields a magic angle close to the experimental value. The reason is that the relativistic correction of the inelastic scattering cross section in anisotropic systems is significantly higher than in isotropic ones.

  • Publication . Conference object . Article . 2018
    Open Access English
    Authors: 
    Adrien Reynaud; M. Leblanc; Stephane Zinola; Philippe Breuil; Jean-Paul Viricelle;
    Publisher: MDPI AG
    Country: France

    International audience; Since 2011, Euro 5b European standard limits the particle number (PN) emissions in addition to the particulate matter (PM) emissions. New thermal engines equipped vehicles have to auto-diagnose their own Diesel particulate filter (DPF) using on-board diagnostic (OBD) sensors. Accumulative resistive soot sensors seem to be good candidates for PM measurements. The aim of this study is to bring more comprehension about soot micro-structures construction in order to link the response of such a sensor to particle size and PN concentration. The sensor sensitivity to the particlesize has been studied using successively an electrostatic and an aerodynamic classification, showing the same trend.

  • Open Access English
    Authors: 
    Estevan L. Lara; Allan A. Constante; Juliano Benfica; Fabian Vargas; A. Boyer; Sonia Ben Dhia; Andreas Gleinser; Gunter Winkler; Bernd Deutschmann;
    Publisher: HAL CCSD
    Country: France

    International audience; Dense integration and high operating frequencies associated with increased number of I/O buffers of FPGAs are factors contributing to electromagnetic emission (EME) increase. Consequently the radiation issue that used to be discussed at PCB level has shifted to component level. Thus it is of high interest and challenging to investigate chip electromagnetic performance. This paper presents a preliminary analysis about the impact of the placement and routing (P&R) process of logic inside the FPGA on the chip EME level. With this purpose, a softcore processor was placed and routed based on three different strategies in the configurable logic block (CLB) array of a commercial FPGA and executed an application code running over an operating system (OS). Three experiments based on farand near-field emission measurements have been performed. The obtained results indicate that the EME level can be affected up to 21.8% by the way the processor is placed and routed inside the FPGA.

  • Publication . Article . Preprint . Conference object . 2017
    Open Access English
    Authors: 
    Dmitri Melikhov; Wolfgang Lucha; Hagop Sazdjian;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Exotic Hadrons (P 29028)

    Scrutinizing the scattering of ordinary mesons in the limiting case of the number of colour degrees of freedom $N_{\rm c}$ of quantum chromodynamics approaching infinity, we formulate Feynman-diagram selection criteria and from these deduce rigorous self-consistency conditions for the manifestation of a tetraquark, a two-quark-two-antiquark bound state, as a pole in the corresponding amplitudes. Our constraints bear rather far-reaching consequences: In particular, all flavour-exotic tetraquarks, composed of four (anti)quarks of disparate flavour, must come in, at least, two variants differing in (and thus readily identifiable by) the large-$N_{\rm c}$ behaviour of their couplings to two ordinary mesons. Quite generally, irrespective of their flavour composition, all tetraquarks prove to be narrow. Their decay rates behave, for large $N_{\rm c},$ like $1/N_{\rm c}^2$ and thus decrease faster than those of ordinary mesons. Comment: 4 pages, 2 figures, contributed to "XVII International Conference on Hadron Spectroscopy and Structure - Hadron2017" (25 - 29 September 2017, Salamanca, Spain)

  • Open Access English
    Authors: 
    Lindenbauer, Edith;
    Publisher: HAL CCSD

    International audience; This paper reports on a qualitative case study about the use of dynamic worksheets addressing typical difficulties and misconceptions concerning functional thinking. The dynamic worksheets designed in this project visualize the transfer between iconic situational and graphical representations and were utilized during an intervention with students in a 7th grade Austrian middle school class. In addition to observational data, diagnostic tests and interviews regarding students’ conceptions in the field of functional thinking were conducted. The case study particularly pays attention to the intuitive conceptions of students, the influence of the dynamic worksheets on these conceptions, and whether or not these materials are able to support students in developing appropriate mathematical conceptions. In this paper, an overview of the study and the part of the results related to students’ use of dynamic worksheets are presented.

  • Publication . Article . Conference object . 2017
    Open Access English
    Authors: 
    Alessandro Chiancone; Florence Forbes; Stéphane Girard;
    Publisher: HAL CCSD
    Country: France
    Project: ANR | PERSYVAL-lab (ANR-11-LABX-0025)

    International audience; Sliced Inverse Regression (SIR) has been extensively used to reduce the dimension of the predictor space before performing regression. SIR is originally a model free method but it has been shown to actually correspond to the maximum likelihood of an inverse regression model with Gaussian errors. This intrinsic Gaussianity of standard SIR may explain its high sensitivity to outliers as observed in a number of studies. To improve robustness, the inverse regression formulation of SIR is therefore extended to non-Gaussian errors with heavy-tailed distributions. Considering Student distributed errors it is shown that the inverse regression remains tractable via an Expectation- Maximization (EM) algorithm. The algorithm is outlined and tested in the presence of outliers, both in simulated and real data, showing improved results in comparison to a number of other existing approaches.

Advanced search in
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
Include:
965 Research products, page 1 of 97
  • Closed Access English
    Authors: 
    Bernard Klonjkowski; Dieter Klein; Sandra Galea; Francoise Gavard; Martine Monteil; Lidia Duarte; Annie Fournier; Sophie Sayon; Kamila Górna; Reinhard Ertl; +4 more
    Publisher: HAL CCSD
    Country: France

    International audience; The evaluation of vaccine strategies in animal models is essential for the development of a vaccine against HIV. In efficacy trials conducted in non-human primate models of AIDS, vaccines based on adenoviruses compared favourably with other vaccine vectors. To determine whether this strategy could be transposed to another animal model, and by extension, to humans, we have evaluated the efficacy of adenoviral vectors in a natural model of AIDS, infection of the cat by the feline immunodeficiency virus (FIV). Recombinant canine adenoviruses expressing the envelope glycoproteins or the Gag protein of a primary strain of FIV were constructed. Three groups of six cats were immunised twice with vectors expressing FIV antigens or with a vector expressing an irrelevant antigen, green fluorescent protein, by intramuscular and subcutaneous routes. Humoral responses were elicited against the transgene product in 6/6, 3/6 and 0/6 cats after immunisation against green fluorescent protein, Gag or the envelope glycoproteins, respectively. Six weeks after the second administration, cats were challenged by the intraperitoneal route with the homologous strain, and viral burden in plasma was followed by quantitative RT-PCR. Immunisation with FIV antigens did not afford protection. Rather, viral RNA was detected at earlier time points in cats immunised against Gag than in cats immunised with a vector expressing an irrelevant antigen. Such immune-mediated enhancement did not appear to have a long-range impact on viral set point or inversion of the CD4(+)/CD8(+) ratio. Thus, in the feline AIDS model pre-existing immunity against a viral antigen exacerbated acute phase infection.

  • Publication . Article . Other literature type . Preprint . Conference object . 2005
    Open Access English
    Authors: 
    Boris Adamczewski; Yann Bugeaud;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Diophantine approximation... (M 822)

    Let $\mathbf{k}$ be an arbitrary field. For any fixed badly approximable power series $\Theta$ in $\mathbf{k}((X^{-1}))$, we give an explicit construction of continuum many badly approximable power series $\Phi$ for which the pair $(\Theta, \Phi)$ satisfies the Littlewood conjecture. We further discuss the Littlewood conjecture for pairs of algebraic power series.

  • Publication . Preprint . Article . Conference object . 2018
    Open Access English
    Authors: 
    Moser, Daniel; Abele, Hartmut; Bosina, Joachim; Fillunger, Harald; Soldner, Torsten; Wang, Xiangzun; Zmeskal, Johann; Konrad, Gertrud;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Particles and Interaction... (W 1252)

    The beta decay of the free neutron provides several probes to test the Standard Model of particle physics as well as to search for extensions thereof. Hence, multiple experiments investigating the decay have already been performed, are under way or are being prepared. These measure the mean lifetime, angular correlation coefficients or various spectra of the charged decay products (proton and electron). NoMoS, the Neutron decay prOducts MOmentum Spectrometer, presents a novel method of momentum spectroscopy: it utilizes the $R \times B$ drift effect to disperse charged particles dependent on their momentum in an uniformly curved magnetic field. This spectrometer is designed to precisely measure momentum spectra and angular correlation coefficients in free neutron beta decay to test the Standard Model and to search for new physics beyond. With NoMoS, we aim to measure inter alia the electron-antineutrino correlation coefficient $a$ and the Fierz interference term $b$ with an ultimate precision of $\Delta a/a < 0.3\%$ and $\Delta b < 10^{-3}$ respectively. In this paper, we present the measurement principles, discuss measurement uncertainties and systematics, and give a status update. Comment: 7 pages, 4 figures, accepted to the Proceedings of the International Workshop on Particle Physics at Neutron Sources PPNS 2018, Grenoble, France, May 24-26, 2018

  • Publication . Conference object . Part of book or chapter of book . Book . 2004
    Open Access English
    Authors: 
    Jakob Puchinger; Günther R. Raidl;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Combining Memetic Algorit... (P 16263)

    International audience; We consider the 3-stage two-dimensional bin packing problem , which occurs in real-world problems such as glass cutting. For it, we present a new integer linear programming formulation and a branch and price algorithm. Column generation is performed by applying either a greedy heuristic or an Evolutionary Algorithm (EA). Computational experiments show the benefits of the EA-based approach. The higher computational effort of the EA pays off in terms of better final solutions; furthermore more instances can be solved to provable optimality.

  • Publication . Other literature type . Article . Conference object . 2004
    Open Access English
    Authors: 
    Bernard Jouffrey; Peter Schattschneider; Cécile Hébert;
    Publisher: HAL CCSD
    Countries: Switzerland, France

    Abstract We resolve the long-standing mysterious discrepancy between the experimental magic angle in EELS— ∼ 2 ϑ E —and the quantum mechanical prediction of ∼ 4 ϑ E . A relativistic approach surpassing the usually applied kinematic correction yields a magic angle close to the experimental value. The reason is that the relativistic correction of the inelastic scattering cross section in anisotropic systems is significantly higher than in isotropic ones.

  • Publication . Conference object . Article . 2018
    Open Access English
    Authors: 
    Adrien Reynaud; M. Leblanc; Stephane Zinola; Philippe Breuil; Jean-Paul Viricelle;
    Publisher: MDPI AG
    Country: France

    International audience; Since 2011, Euro 5b European standard limits the particle number (PN) emissions in addition to the particulate matter (PM) emissions. New thermal engines equipped vehicles have to auto-diagnose their own Diesel particulate filter (DPF) using on-board diagnostic (OBD) sensors. Accumulative resistive soot sensors seem to be good candidates for PM measurements. The aim of this study is to bring more comprehension about soot micro-structures construction in order to link the response of such a sensor to particle size and PN concentration. The sensor sensitivity to the particlesize has been studied using successively an electrostatic and an aerodynamic classification, showing the same trend.

  • Open Access English
    Authors: 
    Estevan L. Lara; Allan A. Constante; Juliano Benfica; Fabian Vargas; A. Boyer; Sonia Ben Dhia; Andreas Gleinser; Gunter Winkler; Bernd Deutschmann;
    Publisher: HAL CCSD
    Country: France

    International audience; Dense integration and high operating frequencies associated with increased number of I/O buffers of FPGAs are factors contributing to electromagnetic emission (EME) increase. Consequently the radiation issue that used to be discussed at PCB level has shifted to component level. Thus it is of high interest and challenging to investigate chip electromagnetic performance. This paper presents a preliminary analysis about the impact of the placement and routing (P&R) process of logic inside the FPGA on the chip EME level. With this purpose, a softcore processor was placed and routed based on three different strategies in the configurable logic block (CLB) array of a commercial FPGA and executed an application code running over an operating system (OS). Three experiments based on farand near-field emission measurements have been performed. The obtained results indicate that the EME level can be affected up to 21.8% by the way the processor is placed and routed inside the FPGA.

  • Publication . Article . Preprint . Conference object . 2017
    Open Access English
    Authors: 
    Dmitri Melikhov; Wolfgang Lucha; Hagop Sazdjian;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Exotic Hadrons (P 29028)

    Scrutinizing the scattering of ordinary mesons in the limiting case of the number of colour degrees of freedom $N_{\rm c}$ of quantum chromodynamics approaching infinity, we formulate Feynman-diagram selection criteria and from these deduce rigorous self-consistency conditions for the manifestation of a tetraquark, a two-quark-two-antiquark bound state, as a pole in the corresponding amplitudes. Our constraints bear rather far-reaching consequences: In particular, all flavour-exotic tetraquarks, composed of four (anti)quarks of disparate flavour, must come in, at least, two variants differing in (and thus readily identifiable by) the large-$N_{\rm c}$ behaviour of their couplings to two ordinary mesons. Quite generally, irrespective of their flavour composition, all tetraquarks prove to be narrow. Their decay rates behave, for large $N_{\rm c},$ like $1/N_{\rm c}^2$ and thus decrease faster than those of ordinary mesons. Comment: 4 pages, 2 figures, contributed to "XVII International Conference on Hadron Spectroscopy and Structure - Hadron2017" (25 - 29 September 2017, Salamanca, Spain)

  • Open Access English
    Authors: 
    Lindenbauer, Edith;
    Publisher: HAL CCSD

    International audience; This paper reports on a qualitative case study about the use of dynamic worksheets addressing typical difficulties and misconceptions concerning functional thinking. The dynamic worksheets designed in this project visualize the transfer between iconic situational and graphical representations and were utilized during an intervention with students in a 7th grade Austrian middle school class. In addition to observational data, diagnostic tests and interviews regarding students’ conceptions in the field of functional thinking were conducted. The case study particularly pays attention to the intuitive conceptions of students, the influence of the dynamic worksheets on these conceptions, and whether or not these materials are able to support students in developing appropriate mathematical conceptions. In this paper, an overview of the study and the part of the results related to students’ use of dynamic worksheets are presented.

  • Publication . Article . Conference object . 2017
    Open Access English
    Authors: 
    Alessandro Chiancone; Florence Forbes; Stéphane Girard;
    Publisher: HAL CCSD
    Country: France
    Project: ANR | PERSYVAL-lab (ANR-11-LABX-0025)

    International audience; Sliced Inverse Regression (SIR) has been extensively used to reduce the dimension of the predictor space before performing regression. SIR is originally a model free method but it has been shown to actually correspond to the maximum likelihood of an inverse regression model with Gaussian errors. This intrinsic Gaussianity of standard SIR may explain its high sensitivity to outliers as observed in a number of studies. To improve robustness, the inverse regression formulation of SIR is therefore extended to non-Gaussian errors with heavy-tailed distributions. Considering Student distributed errors it is shown that the inverse regression remains tractable via an Expectation- Maximization (EM) algorithm. The algorithm is outlined and tested in the presence of outliers, both in simulated and real data, showing improved results in comparison to a number of other existing approaches.

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