Motion processing: the most sensitive detectors differ in temporally localized and extended noise

International audienceContrast thresholds for discriminating orientation and direction of a drifting, oriented grating are usually similar to contrast detection thresholds, which suggest that the most sensitive detectors are labeled for both orientation and direction (Watson and Robson, 1981). This was found to be true in noiseless condition, but Arena et al. (2013) recently found that this was not true in localized noise (i.e., noise having the same spatiotemporal window as the target) as thresholds for discriminating direction were higher than for discriminating orientation. They suggested that this could be explained by the fact that there are more neurons selective to orientation than direction. Another possible interpretation is that, unlike contrast thresholds in absence of noise, the most sensitive detectors in localized noise were labeled for orientation, but not for direction. This hypothesis is supported by recent findings showing different processes operating in localized and extended noise (i.e., full-screen, continuously displayed noise, Allard and Cavanagh, 2011). In the current study, we evaluated contrast thresholds for orientation and direction discrimination tasks in noiseless conditions, and in noise that was either spatially localized or extended, and temporally localized or extended. We found similar orientation and direction thresholds in absence of noise and in temporally extended noise, but greater direction thresholds in temporally localized noise. This suggests that in noiseless and temporally extended noise the most sensitive detectors were labeled for both orientation and direction (e.g., direction-selective complex cells), whereas in temporally localized noise the most sensitive detectors were labeled for orientation but not direction (e.g., simple cells). We conclude that to avoid violating the noise-invariant processing assumption, external noise paradigms investigating motion processing should use noise that is temporally extended, not localized

Étude pilote d‘un programme d‘exercices proactifs dans la maladie de parkinson stades léger à modéré

Travail d'intégration réalisé dans le cadre du cours PHT-6113.Introduction/problématique : Il a été démontré par différentes études que les exercices sont essentiels dans le traitement pharmacologique de la maladie de Parkinson (MP). Toutefois, il existe peu de lignes directrices quant aux paramètres du traitement (fréquence, intensité et durée) de la MP en physiothérapie. Basé sur une combinaison de différentes techniques (Think Big, Tai Chi, Kayak, etc.), un nouveau programme d‘exercices a été développé par Mai Pham, pht au CHUM ND et deux étudiantes. Aucune étude n‘avait été réalisée pour déterminer sa faisabilité. Objectif : Évaluer la faisabilité du PEP et déterminer quelles incapacités résultant de la maladie pourraient être améliorées par ce programme. Méthodologie : 11 participants atteints de la maladie de Parkinson idiopathique, (Stade Hoehn & Yahr de 1 à 3) ont réalisé le programme d‘exercices 2 x / sem. pendant 6 semaines dont 4 séances à la maison. Résultats : Des améliorations significatives ont été observées à la mobilité au lit (sans couverture, p = 0.016, avec couverture, p = 0.006), au test assis-debout (p = 0.005) et au TUG avec tasse (p = 0.01). Les résultats montrent aussi une diminution de la mobilité cervicale (perte d‘extension, p = 0.016). Conclusion : La faisabilité du programme a été démontrée. Bien qu'il n'ait pas été possible de conclure sur l'efficacité du PEP, certaines variables semblent être améliorées par le PEP

Experimental investigation on the concentration and voltage effects on the characteristics of deposited magnesium–lanthanum powder

International audiencePhone: +33 248 484 065 Highlights x We synthetize Mg-La powders by means of an electrodeposition process. x We characterize Mg-La powders using EDS, SEM, XRD and FTIR techniques

Trail Making Test performance contributes to subjective judgment of visual efficiency in older adults

Introduction: The determinant factors that influence self-reported quality of vision have yet to be fully elucidated. This study evaluated a range of contextual information, established psychophysical tests, and in particular, a series of cognitive tests as potentially novel determinant factors.   Materials & Methods: Community dwelling adults (aged 50+) recruited to Wave 1 of The Irish Longitudinal Study on Ageing, excluding those registered blind, participated in this study (N = 5,021). Self-reports of vision were analysed in relation to visual acuity and contrast sensitivity, ocular pathology, visual (Choice Response Time task; Trail Making Test) and global cognition. Contextual factors such as having visited an optometrist and wearing glasses were also considered. Ordinal logistic regression was used to determine univariate and multivariate associations.   Results and Discussion: Poor Trail Making Test performance (Odds ratio, OR = 1.36), visual acuity (OR = 1.72) and ocular pathology (OR = 2.25) were determinant factors for poor versus excellent vision in self-reports. Education, wealth, age, depressive symptoms and general cognitive fitness also contributed to determining self-reported vision.   Conclusions: Trail Making Test contribution to self-reports may capture higher level visual processing and should be considered when using self-reports to assess vision and its role in cognitive and functional health

Phosphorylation by Akt within the ST loop of AMPK-α1 down-regulates its activation in tumour cells

The insulin/IGF-1 (insulin-like growth factor 1)-activated protein kinase Akt (also known as protein kinase B) phosphorylates Ser(487) in the ‘ST loop’ (serine/threonine-rich loop) within the C-terminal domain of AMPK-α1 (AMP-activated protein kinase-α1), leading to inhibition of phosphorylation by upstream kinases at the activating site, Thr(172). Surprisingly, the equivalent site on AMPK-α2, Ser(491), is not an Akt target and is modified instead by autophosphorylation. Stimulation of HEK (human embryonic kidney)-293 cells with IGF-1 caused reduced subsequent Thr(172) phosphorylation and activation of AMPK-α1 in response to the activator A769662 and the Ca(2+) ionophore A23187, effects we show to be dependent on Akt activation and Ser(487) phosphorylation. Consistent with this, in three PTEN (phosphatase and tensin homologue deleted on chromosome 10)-null tumour cell lines (in which the lipid phosphatase PTEN that normally restrains the Akt pathway is absent and Akt is thus hyperactivated), AMPK was resistant to activation by A769662. However, full AMPK activation could be restored by pharmacological inhibition of Akt, or by re-expression of active PTEN. We also show that inhibition of Thr(172) phosphorylation is due to interaction of the phosphorylated ST loop with basic side chains within the αC-helix of the kinase domain. Our findings reveal that a previously unrecognized effect of hyperactivation of Akt in tumour cells is to restrain activation of the LKB1 (liver kinase B1)–AMPK pathway, which would otherwise inhibit cell growth and proliferation

The effect of long-term water level drawdown on the vegetation composition and CO2 fluxes of a boreal peatland in central Finland

Cette étude a permis d’acquérir une meilleure compréhension des implications potentielles du réchauffement climatique sur les tourbières dominées par les sphaignes. Le drainage d’une partie de la tourbière a débuté il y a 55 ans. La composition végétale des parties naturelle et drainée a été comparée à l’aide de six transects et analysée par des techniques d’ordination. Les flux de CO2 ont été mesurés durant la saison de croissance sur un transect de la partie drainée et modélisés. En réponse au drainage, la composition végétale a changé et ce n’était pas relié au gradient naturel centre-bordure. Dans la partie humide du transect (éloigné du canal de drainage), la photosynthèse et la respiration totale ont diminué. La captation du CO2 y était légèrement moins élevée que dans la partie sèche. Cette étude suggère que les effets des changements climatiques seraient atténués par un changement des communautés végétales.This study is providing a better understanding of the potential implications of the global climatic warming on Sphagnum dominated peatlands. The drainage of a part of the peatland began 55 years ago. Vegetation composition of the drained and natural areas was compared along six transects and analysed by ordination techniques. CO2 fluxes were measured during the growing season on one transect of the drained area and inferred by modelling. In response to drainage, vegetation composition changed and it was not related to a natural mire margin-mire expanse gradient. In the wetter part of the transect (far from the drainage ditch), gross photosynthesis and total respiration decreased. There was also slightly less CO2 sequestration than in the drier part. This study suggests for Sphagnum dominated peatlands that the effect of climate change might be reduced by a change of vegetation communities

Ministerial Education Councils’ Capacity for Policy Decision-Making in Canada, Germany, and Switzerland: Finding a Balanced Perspective

Scholars have become increasingly vigilant about leaders, the role of government and wider governance bodies, and their influence on education policy. Councils in Europe and North America, generally, and education councils, specifically, are good examples of influential bodies whose decision-making processes have rightfully come under scrutiny; however, many scholarly assessments have been characterized by rhetorical claims that focus on these bodies’ limited ability to make decisions and address social challenges. This article details a qualitative, comparative case study conducted in 2018 that investigated how Councils of Ministers of Education in Canada, Germany, and Switzerland address national educational issues of collective interest. The resulting dataset is comprehensive, and this research invites colleagues to refine or rethink some of their limiting rhetorical tools and underlying assumptions

The Expense Tied to Secondary Course Failure: The case of Ontario

This article describes a study that examined the volume of secondary course failure and its direct budget impact on Ontario’s K–12 public education system. The study employed a straightforward, descriptive accounting method to estimate the annual expenditure tied to secondary course failure, taking into account some factors known to be systemically related (e.g., grade level, subject area, additional services received). Other studies have used secondary dropouts as the measure of failure and estimated the private or public costs; this study focused on the direct budget impact of secondary course failures on districts and the school system. In the 2008–2009 year, there were approximately 5,082,543 secondary course attempts across 70 school boards in Ontario: 4,682,535 were completed successfully (passed) and 400,008 were unsuccessfully completed (failed). I estimated the total level of expenditure tied to failure for Ontario’s public education system to be $472,729,698, or 7.7% of total instructional and operational spending. My findings point to practical applications that could help district and system leaders in their work to drive positive educational outcomes. I also provide a methodological framework for thinking about levels of expenditure tied to secondary course failure at the system and school board levels. Currently no such framework exists in the public realm