Orienting of willed temporal attention: an EEG study

Temporal attention enables people to select relevant stimuli across time allowing for prioritisation of information. In most studies on temporal orienting external cues have been used to direct participants' attention. However, in everyday life, we also make internal choices, without external cues, of when to orient our attention. Recent studies in visual-spatial attention developed a paradigm aiming to explore how voluntary attention is initiated and controlled when no direct instructions are used. This paradigm includes a new type of trial in which a participant is asked to choose where to orient their attention (willed attention) in contrast to being instructed where to orient their attention (instructed attention). The current study draws on this distinction and it aims to explore whether and how willed temporal attention affects behaviour and whether it is different from instructed temporal attention by looking at both behavioural data as well as EEG. To explore that question the temporal cueing task was used in which a cue instructed a participant to anticipate either short (800 ms) or a long (2000 ms) interval between cue and target presentation times. Alternatively, a cue instructed a participant to decide for themselves to expect the target after one of these two intervals. The experiment demonstrated no significant differences in RTs and EEG recordings. However, a difference between two attention types in the CNV recorded in the time interval directly preceding the target in the short cue-target interval showed a medium effect size. Furthermore, a comparison of the CNV recorded in the willed and instructed attention in the post cue time interval demonstrated medium effect size with posterior scalp distribution. It was only recorded in the short cue-target interval. There, also, was a lateralised activity in the N1 time range in the instructed attention condition. Finally, a small decrease in the power of the theta activity was observed in the willed attention condition in the long cue-target interval at the Fz electrode. These differences could potentially become significant with more power. To the author's knowledge, this is the first study on electrophysiological correlates of willed temporal attention, and it demonstrates the feasibility of the paradigm used

Infrared light emission from atomic point contacts

Gold atomic point contacts are prototype systems to evidence ballistic electron transport. The typical dimension of the nanojunction being smaller than the electron-phonon interaction length, even at room temperature, electrons transfer their excess energy to the lattice only far from the contact. At the contact however, favored by huge current densities, electron-electron interactions result in a nano hot electron gas acting as a source of photons. Using a home built Mechanically Controlled Break Junction, it is reported here, for the first time, that this hot electron gas also radiates in the infrared range (0.2eV to 1.2eV). Moreover, in agreement with the pioneering work of Tomchuk, we show that this radiation is compatible with a blackbody like spectrum emitted from an electron gas at temperatures of several thousands of Kelvin given by $(kB.Te)^2 = \alpha. I.V$ where $\alpha$, $I$ and $V$ are respectively a fitting parameter, the current flowing and the applied bias.Comment: 13 pages, 5 figure

Estimating single molecule conductance from spontaneous evolution of a molecular contact

We present an original method to estimate the conductivity of a single molecule anchored to nanometric-sized metallic electrodes, using a Mechanically Controlled Break Junction (MCBJ) operated at room temperature in liquid. We record the conductance through the metal / molecules / metal nanocontact while keeping the metallic electrodes at a fixed distance. Taking advantage of thermal diffusion and electromigration, we let the contact naturally explore the more stable configurations around a chosen conductance value. The conductance of a single molecule is estimated from a statistical analysis of raw conductance and conductance standard deviation data for molecular contacts containing up to 14 molecules. The single molecule conductance values are interpreted as time-averaged conductance of an ensemble of conformers at thermal equilibrium.Comment: 25 pages, 6 figure

Facilitating Psychosocial Adjustment to Traumatic Amputations: Perspectives of Occupational Therapists

The purpose of this qualitative study was to explore the perspectives and experiences of three occupational therapists in the United States in addressing psychosocial reaction and adjustment in the treatment of individuals with traumatic amputations. Occupational therapists with extensive experience working with clients with traumatic amputations were selected as participants. Data from the participant interviews revealed two major themes: (1) Individuals’ internal resources and response to amputation influence psychosocial adjustment and (2) Occupational therapists addressing psychosocial reactions in individuals with traumatic amputations in the context of treatment. The first theme “Individuals’ internal resources…” had two subthemes: (a) the influence of individuals’ internalized resources and responses, and (b) family support, culture and background. The second theme, “occupational therapists addressing psychosocial reactions…” had two subthemes: (a) occupation based, client centered treatment, and (b) therapeutic use of self. These themes demonstrated that individuals’ pre-morbid coping skills and external supports are crucial factors in adjusting to a traumatic amputation, and that occupational therapists’ use of meaningful activities and a therapeutic use of self, as well as appropriate timing of treatment can give the best support to the client. This study suggests that understanding a client on a deeper level and finding out what is motivating to that client are the best ways to promote psychosocial adjustment to a traumatic amputation

Learning Smooth Pooling Regions for Visual Recognition

From the early HMAX model to Spatial Pyramid Matching, spatial pooling has played an important role in visual recognition pipelines. By aggregating local statistics, it equips the recognition pipelines with a certain degree of robustness to translation and deformation yet preserving spatial information. Despite of its predominance in current recognition systems, we have seen little progress to fully adapt the pooling strategy to the task at hand. In this paper, we propose a flexible parameterization of the spatial pooling step and learn the pooling regions together with the classifier. We investigate a smoothness regularization term that in conjuncture with an efficient learning scheme makes learning scalable. Our framework can work with both popular pooling operators: sum-pooling and max-pooling. Finally, we show benefits of our approach for object recognition tasks based on visual words and higher level event recognition tasks based on object-bank features. In both cases, we improve over the hand-crafted spatial pooling step showing the importance of its adaptation to the task