2,981 research outputs found

    Cheminements et ouvertures sur des espaces intimes : regards sur le théâtre de Thomas Kilroy

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    L’oeuvre de Thomas Kilroy est incontournable pour quiconque s’intéresse au théâtre irlandais contemporain. Par l’entremise de son oeuvre, cet auteur cherche à remettre en question les certitudes communautaires : l’homosexualité, la religion, les visions claniques mortifères sont des leitmotivs qui traversent ses pièces. Son association avec la compagnie théâtrale « Field Day » — reconnue pour ses prises de position politiques —, est également étudiée, et ce, pour souligner l’importance de sa contribution au théâtre irlandais en tant qu’artiste et en tant qu’animateur.Thomas Kilroy's work is considered seminal in the field of contemporary Irish drama. Through his work, Kilroy challenges communal certainties: homosexuality, religion, deadly clannish beliefs are leitmotifs that mark his oeuvre. His association with Field Day Theatre Company—known for its political activism—, is also studied in order to highlight his contribution to Irish theatre both as an artist and as a facilitator

    Stride-to-stride variability while backward counting among healthy young adults

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    BACKGROUND: Little information exists about the involvement of attention in the control of gait rhythmicity. Variability of both stride time and stride length is closely related to the control of the rhythmic stepping mechanism. We sought 1) to determine whether backward counting while walking could provoke significant gait changes in mean values and coefficients of variation of stride velocity, stride time and stride length among healthy young adults; and 2) to establish whether change in stride-to-stride variability could be related to dual-task related stride velocity change, attention, or both. METHODS: Mean values and coefficients of variation of stride velocity, stride time and stride length were recorded using the Physilog(®)-system, at a self-selected walking speed in 49 healthy young adults (mean age 24.1 ± 2.8 years, women 49%) while walking alone and walking with simultaneous backward counting. Performance on backward counting was evaluated by recording the number of figures counted while sitting alone and while walking. RESULTS: Compared with walking alone, a significant dual-task-related decrease was found for the mean values of stride velocity (p < 0.001), along with a small but significant increase for the mean values and coefficients of variation of stride time (p < 0.001 and p = 0.015, respectively). Stride length parameters did not change significantly between both walking conditions. Dual-task-related increase of coefficient of variation of stride time was explained by changing stride velocity and variability between subjects but not by backward counting. The number of figures counted while walking decreased significantly compared to backward counting alone. Further, the dual-task related decrease of the number of enumerated figures was significantly higher than the dual-task related decrease of stride velocity (p = 0.013). CONCLUSION: The observed performance-changes in gait and backward counting while dual tasking confirm that certain aspects of walking are attention-demanding in young adults. In the tested group of 49 young volunteers, dual tasking caused a small decrease in stride velocity and a slight increase in the stride-to-stride variability of stride time, while stride velocity variability was not affected by the attention-demanding task. The increase in stride time variability was apparently the result of a change in gait speed, but not a result of dual tasking. This suggests that young adults require minimal attention for the control of the rhythmic stepping mechanism while walking

    Motivations des bénévoles : une revue de la littérature.

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    Après avoir montré l’importance des bénévoles comme ressource des associations, cette communication pose la question de la nature et de l’intensité de leurs motivations. Une revue des travaux de recherche est alors proposée, pour aboutir à une typologie basée sur la nature des hypothèses et sur la méthodologie utilisée. Pour finir, nous montrons que des travaux en Sciences de Gestion pourraient certainement enrichir le débat sur cette question de recherche.Motivations, bénévoles, modèles économiques, modèles sociologiques, psychologie sociale

    Artificial Intelligence with Light Supervision: Application to Neuroimaging

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    Recent developments in artificial intelligence research have resulted in tremendous success in computer vision, natural language processing and medical imaging tasks, often reaching human or superhuman performance. In this thesis, I further developed artificial intelligence methods based on convolutional neural networks with a special focus on the automated analysis of brain magnetic resonance imaging scans (MRI). I showed that efficient artificial intelligence systems can be created using only minimal supervision, by reducing the quantity and quality of annotations used for training. I applied those methods to the automated assessment of the burden of enlarged perivascular spaces, brain structural changes that may be related to dementia, stroke, mult

    Un exemple de stratégie de renforcement de moyennes entreprises : l'échange relationnel comme moyen de gérer la dépendance économique vis-à-vis des clients.

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    Parmi les options stratégiques des moyennes entreprises (ME), les stratégies de renforcement visant à gérer la dépendance économique vis-à-vis des clients, peuvent s'avérer un facteur de vulnérabilité (Saporta, 1989). La mise en place d'un échange relationnel entre la ME et ses clients relève selon nous, de ce type de stratégie. Après avoir défini l'échange relationnel, cet article présente les résultats d'une étude empirique portant sur les relations de trente ME françaises avec leur plus gros client, appartenant à trois secteurs industriels. Il y apparaît qu'une facette de l'échange relationnel, à savoir le souhait d'établir une relation à long terme, permet aux ME de rendre, à leur tour, leur plus gros client déopendant d'elles-mêmes. En instaurant une dépendance mutuelle, l'échange relationnel rend ainsi caduc le lien entre dépendance économique et vulnérabilité de la ME.dépendance économique, échange relationnel, stratégie

    Point-diffraction interferometry for wavefront sensing in adaptive optics

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    The work presented in this thesis aims at the development and validation of a wavefront sensor concept for adaptive optics (AO) called the pupil-modulated Point-Diffraction Interferometer (m-PDI). The m-PDI belongs to a broader family of wavefront sensors called Point-Diffraction Interferometers (PDIs), which make use of a small pinhole to filter a portion of the incoming light, hence generating a reference beam. This allows them to perform wavefront sensing on temporally incoherent light, such as natural guide stars in the context of astronomical AO. Due to their high sensitivity, PDIs are being developed to address several difficult problems in AO, namely measuring quasi-static aberrations to a high degree of accuracy, the cophasing of segmented apertures, and reaching a high correction regime known as extreme AO. But despite their advantages, they remain limited by their narrow chromatic range, around ∆λ = 2% relative to central bandwidth, and short dynamic range, generally of ±π/2. The purpose of developing the m-PDI is to explore whether this new concept has any ad- vantages regarding these limitations. Indeed, we find that the m-PDI has a maximum chromatic bandwidth of 66% relative to the central wavelength and a dynamic range at least 4 times larger than that of other PDIs. Although the m-PDI concept had been proposed previously, it had not been explored to the extent reached in this manuscript. This thesis presents an initial investigation into the m-PDI, beginning with the development of the theory. Here the theoretical framework is laid out to explain how interference fringes are modulated by the wavefront, how to then demodulate the propa- gating electric field’s phase and then finally how to measure the signal-to-noise ratio (SNR). After building analytical and numerical models, a prototype is designed, built and characterised using CHOUGH, a high-order AO testbed in the lab. This incarnation of the m-PDI is called the Calibration & Alignment Wavefront Sensor (CAWS). The characterisation of the CAWS shows two things. The first one is that the CAWS’ response is approximately flat across its spatial frequency domain. The second one is that its dynamic range decreases at higher frequencies, suggesting that it depends, amongst other things, on the wavefront’s slope. In order to prove that m-PDIs can be used for AO, a control loop is closed using the CAWS and CHOUGH’s deformable mirror, with both monochromatic and broadband light. The results show that the final Strehl ratio increases from 0.2 to 0.66, at a wavelength of 633 nm. The difference in residual aberrations seen separately by the imaging camera and by the CAWS is about 20 nm RMS. This is explained by non-common path aberrations and low order aberrations which are invisible to the CAWS. Finally, the instrument was tested on the CANARY AO bench at the William Herschel Telescope. The CAWS was successful at characterising the quasi- static aberrations of the system and at demodulating the phase of wavefronts produced with the deformable mirror. When demodulating on-sky residual aberrations at the back of CANARY’s single-conjugate AO loop, the SNR remained too low for effective wavefront demodulation, only sporadically in- creasing above 1. These results are not discouraging as the CAWS was only a first prototype and CANARY is not a high-order system, reaching a Strehl ratio of around 0.5% at 675 nm. The lessons and improvements for future de- signs are to increase the diameter of the instrument’s pinhole by at least twice, and deliver it a higher Strehl ratio by moving towards longer wavelengths and employing a higher order AO system

    Large 2D Coulomb crystals in a radio frequency surface ion trap

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    We designed and operated a surface ion trap, with an ion-substrate distance of 500\mum, realized with standard printed-circuit-board techniques. The trap has been loaded with up to a few thousand Sr+ ions in the Coulomb-crystal regime. An analytical model of the pseudo-potential allowed us to determine the parameters that drive the trap into anisotropic regimes in which we obtain large (N>150) purely 2D ion Coulomb crystals. These crystals may open a simple and reliable way to experiments on quantum simulations of large 2D systems.Comment: 4 pages, 4 figure
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