310 research outputs found
Les figures spatiales dans L’île de la Merci d’Élise Turcotte ou la maison de l’emprisonnement
Depuis les annĂ©es 1980, la figure de la maison occupe une place prĂ©pondĂ©rante dans la littĂ©rature quĂ©bĂ©coise et dans les autres littĂ©ratures francophones de l’AmĂ©rique du Nord. Ce fait s’avère d’autant plus vrai dans l’oeuvre romanesque d’Élise Turcotte. Dans L’île de la Merci (1997), la maison et d’autres figures spatiales importantes permettent au lecteur d’unir des Ă©vĂ©nements narratifs, de recouper des faisceaux de sens Ă première vue disparates. Afin de mieux rendre compte des modalitĂ©s des figures spatiales dans cette oeuvre, nous utiliserons une approche qu’il convient de dĂ©finir comme l’hermĂ©neutique des espaces fictionnels. Cette approche lie les trois concepts centraux de l’hermĂ©neutique — comprĂ©hension, explication et interprĂ©tation — Ă trois concepts spatiaux, soit la figure spatiale, la configuration spatiale et la refiguration spatiale.Since the 1980s, the figure of the house has played a dominant role in the literature of Quebec and other French-speaking literatures of North America. This is particularly true of the novels of Élise Turcotte. In L’île de la Merci (1997), the house and other significant spatial figures allow the reader to unite narrative events and to tie up strands of meaning that initially appear disjointed. To provide a better account of the forms assumed by spatial figures in this novel, we will use an approach that can be defined as a hermeneutics of fictional spaces. This approach links the three central concepts of hermeneutics—understanding, explanation and interpretation—with three spatial concepts, i.e., the spatial figure, spatial configuration and spatial refiguration.Desde los años 1980, el tema de la casa ocupa un lugar preponderante en la literatura quebequense y en las demás literaturas francĂłfonas de AmĂ©rica del Norte, hecho que resulta aĂşn más patente en la obra novelesca de Élise Turcotte. En L’île de la Merci (1997), la casa y otras importantes figuras espaciales permiten que el lector asocie eventos narrativos, haga coincidir un espectro de significados que, a primera vista, parecĂan discordantes. A fin de informar mejor sobre las modalidades de las figuras espaciales en esta obra, utilizaremos un enfoque que conviene definir como la hermenĂ©utica de los espacios ficcionales. Este enfoque reĂşne los tres conceptos centrales de la hermenĂ©utica –comprensiĂłn, explicaciĂłn e interpretaciĂłn– con tres conceptos espaciales, esto es, la figura espacial, la configuraciĂłn espacial y la refiguraciĂłn espacial
L'information différentielle : une solution à la surabondance des normes ?
La présente étude empirique questionne l'efficacité du principe de l'information différentielle adoptée au Canada. Une analyse de contenu des états financiers d'un échantillon aléatoire de 240 PME québécoises, permet notamment de constater la fréquence d'utilisation de ce principe, à la lumière de certaines caractéristiques des entreprises.comptabilité; états financiers; normes; PME; harmonisation
Anisotropie de la photoluminescence dans des nanostructures organiques chirales autoassemblées
Nous investiguons dans ce travail la dynamique des excitons dans une couche mince
d’agrégats H autoassemblés hélicoïdaux de molécules de sexithiophène. Le couplage intermoléculaire
(J=100 meV) place ce matĂ©riau dans la catĂ©gorie des semi-conducteurs Ă
couplage de type intermédiaire. Le désordre énergétique et la forte interaction électronsphonons
causent une forte localisation des excitons. Les espèces initiales se ramifient
en deux Ă©tats distincts : un Ă©tat d’excitons autopiĂ©gĂ©s (rendement de 95 %) et un Ă©tat Ă
transfert de charge (rendement de 5%). À température de la pièce (293K), les processus
de sauts intermoléculaires sont activés et l’anisotropie de la fluorescence décroît rapidement
à zéro en 5 ns.
À basse température (14K), les processus de sauts sont gelés. Pour caractériser la dynamique
de diffusion des espèces, une expérience d’anisotropie de fluorescence a été
effectuée. Celle-ci consiste à mesurer la différence entre la photoluminescence polarisée
parallèlement au laser excitateur et celle polarisée perpendiculairement, en fonction du
temps. Cette mesure nous donne de l’information sur la dépolarisation des excitons, qui
est directement reliée à leur diffusion dans la structure supramoléculaire.
On mesure une anisotropie de 0,1 après 20 ns qui perdure jusqu’à 50ns. Les Ă©tats Ă
transfert de charge causent une remontée de l’anisotropie vers une valeur de 0,15 sur
une plage temporelle allant de 50 ns jusqu’à 210 ns (période entre les impulsions laser).
Ces résultats démontrent que la localisation des porteurs est très grande à 14K,
et qu’elle est supérieure pour les espèces à transfert de charge. Un modèle numérique
simple d’équations différentielles à temps de vie radiatif et de dépolarisation constants
permet de reproduire les données expérimentales. Ce modèle a toutefois ses limitations,
notamment en ce qui a trait aux mécanismes de dépolarisation des excitons.In this work, we investigate exciton dynamics in a thin film of sexithiophene molecules
in self-assembled chiral H-aggregate supramolecular stacks. The intermolecular coupling
energy J=100 meV places those molecules in the intermediate coupling regime.
The energetic disorder and the strong phonon-electron interactions leads to high localization
of the photoexcitations. The initial photoexcited species branches into two distinct
states : self-trapped exciton (95% yield) and charge-transfer excitons (5% yield). At
room temperature (293K), the intermolecular hopping processes are thermaly activated
and the fluorescence anisotropy goes to zero within 5 ns.
At low temperature (14K), hopping processes are frozen. To characterize exciton diffusion
mechanisms, a fluorescence anisotropy experiment has been done. This measurement
consists of monitoring the difference between the parallel and perpendicular composants
of the photoluminescence (with respect to the laser beam), as a function of time.
The fluorescence anisotropy gives us information about the depolarization of the excitons,
which is directly connected with their diffusion within the supramolecular stack.
We measure an anisotropy of 0,1 after 20 ns which stays constant for 50 ns. Chargetransfer
states induce a rise of the anisotropy up to 0,15 between 50 ns and 210 ns (the
period between adjacent laser pulses). Those measurements shows that exciton localization
is very strong at 14K and higher for the charge-transfer states than the self-trapped
ones. A simple mathematical model based on the resolution of a system of differential
equations with constants radiative and depolarization lifetimes can reproduce the experimental
data. This model has some limitations, especially for the description of the
depolarization mechanisms of the self-trapped excitons
A wireless electro-optic platform for multimodal electrophysiology and optogenetics in freely moving rodents
This paper presents the design and the utilization of a wireless electro-optic platform to perform simultaneous multimodal electrophysiological recordings and optogenetic stimulation in freely moving rodents. The developed system can capture neural action potentials (AP), local field potentials (LFP) and electromyography (EMG) signals with up to 32 channels in parallel while providing four optical stimulation channels. The platform is using commercial off-the-shelf components (COTS) and a low-power digital field-programmable gate array (FPGA), to perform digital signal processing to digitally separate in real time the AP, LFP and EMG while performing signal detection and compression for mitigating wireless bandwidth and power consumption limitations. The different signal modalities collected on the 32 channels are time-multiplexed into a single data stream to decrease power consumption and optimize resource utilization. The data reduction strategy is based on signal processing and real-time data compression. Digital filtering, signal detection, and wavelet data compression are used inside the platform to separate the different electrophysiological signal modalities, namely the local field potentials (1–500 Hz), EMG (30–500 Hz), and the action potentials (300–5,000 Hz) and perform data reduction before transmitting the data. The platform achieves a measured data reduction ratio of 7.77 (for a firing rate of 50 AP/second) and weights 4.7 g with a 100-mAh battery, an on/off switch and a protective plastic enclosure. To validate the performance of the platform, we measured distinct electrophysiology signals and performed optogenetics stimulation in vivo in freely moving rondents. We recorded AP and LFP signals with the platform using a 16-microelectrode array implanted in the primary motor cortex of a Long Evans rat, both in anesthetized and freely moving conditions. EMG responses to optogenetic Channelrhodopsin-2 induced activation of motor cortex via optical fiber were also recorded in freely moving rodents
Intuitive adaptive orientation control of assistive robots for people living with upper limb disabilities
Robotic assistive devices enhance the autonomy of individuals living with physical disabilities in their day-to-day life. Although the first priority for such devices is safety, they must also be intuitive and efficient from an engineering point of view in order to be adopted by a broad range of users. This is especially true for assistive robotic arms, as they are used for the complex control tasks of daily living. One challenge in the control of such assistive robots is the management of the end-effector orientation which is not always intuitive for the human operator, especially for neophytes. This paper presents a novel orientation control algorithm designed for robotic arms in the context of human-robot interaction. This work aims at making the control of the robot's orientation easier and more intuitive for the user, in particular, individuals living with upper limb disabilities. The performance and intuitiveness of the proposed orientation control algorithm is assessed through two experiments with 25 able-bodied subjects and shown to significantly improve on both aspects
A low-cost, wireless, 3-D-printed custom armband for sEMG hand gesture recognition
Wearable technology can be employed to elevate the abilities of humans to perform demanding and complex tasks more efficiently. Armbands capable of surface electromyography (sEMG) are attractive and noninvasive devices from which human intent can be derived by leveraging machine learning. However, the sEMG acquisition systems currently available tend to be prohibitively costly for personal use or sacrifice wearability or signal quality to be more affordable. This work introduces the 3DC Armband designed by the Biomedical Microsystems Laboratory in Laval University; a wireless, 10-channel, 1000 sps, dry-electrode, low-cost ( 150 USD) myoelectric armband that also includes a 9-axis inertial measurement unit. The proposed system is compared with the Myo Armband by Thalmic Labs, one of the most popular sEMG acquisition systems. The comparison is made by employing a new offline dataset featuring 22 able-bodied participants performing eleven hand/wrist gestures while wearing the two armbands simultaneously. The 3DC Armband systematically and significantly (p < 0.05) outperforms the Myo Armband, with three different classifiers employing three different input modalities when using ten seconds or more of training data per gesture. This new dataset, alongside the source code, Altium project and 3-D models are made readily available for download within a Github repository
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