On General Axial Gauges for QCD

General Axial Gauges within a perturbative approach to QCD are plagued by 'spurious' propagator singularities. Their regularisation has to face major conceptual and technical problems. We show that this obstacle is naturally absent within a Wilsonian or 'Exact' Renormalisation Group approach and explain why this is so. The axial gauge turns out to be a fixed point under the flow, and the universal 1-loop running of the gauge coupling is computed.Comment: 4 pages, latex, talk presented by DFL at QCD'98, Montpellier, July 2-8, 1998; to be published in Nucl. Phys. B (Proc. Suppl.

Reading from a Head-Fixed Display during Walking: Adverse Effects of Gaze Stabilization Mechanisms

International audienceReading performance during standing and walking was assessed for information presented on earth-fixed and head-fixed displays by determining the minimal duration during which a numerical time stimulus needed to be presented for 50% correct naming answers. Reading from the earth-fixed display was comparable during standing and walking, with optimal performance being attained for visual character sizes in the range of 0.2 degrees to 1 degrees. Reading from the head-fixed display was impaired for small (0.2-0.3 degrees) and large (5 degrees) visual character sizes, especially during walking. Analysis of head and eye movements demonstrated that retinal slip was larger during walking than during standing, but remained within the functional acuity range when reading from the earth-fixed display. The detrimental effects on performance of reading from the head-fixed display during walking could be attributed to loss of acuity resulting from large retinal slip. Because walking activated the angular vestibulo-ocular reflex, the resulting compensatory eye movements acted to stabilize gaze on the information presented on the earth-fixed display but destabilized gaze from the information presented on the head-fixed display. We conclude that the gaze stabilization mechanisms that normally allow visual performance to be maintained during physical activity adversely affect reading performance when the information is presented on a display attached to the head

How are coastal benthos fed?

Water movement can influence the distribution of benthos, in part, by increasing food delivery; however, the impact of advective transport and turbulent diffusion on organic matter flux to nearshore benthic communities is not well quantified. In this study, we measured the vertical particulate organic carbon (POC) and particulate phosphorus (PP) flux in nearshore Lake Michigan using two naturally occurring daughter/parent radionuclide pairs (234Th/238U and 90Y/90Sr) and compared these fluxes to coincident benthic chamber estimates of respiration and total phosphorus efflux by quagga mussels on the lakebed. We found that advective onshore transport and vertical convective mixing increased POC and PP flux to the nearshore benthos by a factor of ~15 and ~30 over offshore trap-derived estimates of flux. From these results, we hypothesize that high benthos population densities are related to an edge effect created when the dominant mechanism of particle delivery transitions from gravitational settling to convection

Advances, limitations and future perspectives in the diagnosis and management of dry eye in Sjogren's syndrome

Primary Sjogren's syndrome is a complex systemic autoimmune disorder that primarily affects exocrine glands such as the lacrimal glands. Dry eye disease is one of the most prevalent complications of Sjogren's syndrome, affecting most patients. It significantly impairs quality of life and management is often difficult and unsatisfactory, in part due to weak correlation between symptoms and signs and poor recognition of the three main subtypes aqueous-deficient, evaporative and neuropathic dry eye. This review provides an overview of key aspects of dry eye disease, such as its multifactorial aetiology and recent insights into pathophysiology. The uses and pitfalls of commonly-used diagnostic tests for dry eye are reviewed, as well as the increasing number of new imaging technologies and biomarkers to refine diagnosis. There are many current and emerging treatment options for dry eye in Sjogren's syndrome, but high-level evidence of efficacy is mostly lacking, as are evidence-based treatment algorithms. All these aspects make the management of dry eye in Sjogren's syndrome challenging

Advances, limitations and future perspectives in the diagnosis and management of dry eye in Sjogren's syndrome

Primary Sjogren's syndrome is a complex systemic autoimmune disorder that primarily affects exocrine glands such as the lacrimal glands. Dry eye disease is one of the most prevalent complications of Sjogren's syndrome, affecting most patients. It significantly impairs quality of life and management is often difficult and unsatisfactory, in part due to weak correlation between symptoms and signs and poor recognition of the three main subtypes aqueous-deficient, evaporative and neuropathic dry eye. This review provides an overview of key aspects of dry eye disease, such as its multifactorial aetiology and recent insights into pathophysiology. The uses and pitfalls of commonly-used diagnostic tests for dry eye are reviewed, as well as the increasing number of new imaging technologies and biomarkers to refine diagnosis. There are many current and emerging treatment options for dry eye in Sjogren's syndrome, but high-level evidence of efficacy is mostly lacking, as are evidence-based treatment algorithms. All these aspects make the management of dry eye in Sjogren's syndrome challenging

Stratégies d'évitement de collision en intersection

ACAPS 2015 - 16ème Congrès de l'Association des Chercheurs en Activités Physiques et Sportives, Nantes, FRANCE, 26-/10/2015 - 28/10/2015Dans la littérature, certaines études révèlent un effet de la taille des véhicules croisés sur des tâches de jugement et de comportement de conduite des automobilistes à une intersection. Néanmoins, dans ces études, la taille et le type de véhicules croisés (e.g., voiture vs motocyclette) covariaient systématiquement. Cette étude examine séparément l'incidence de la taille et du type de véhicules croisés sur une tâche de jugement et une tâche de franchissement réel d'intersection. Pour cela les voitures et les motocyclettes observées avaient les mêmes dimensions. 14 participants ont réalisé deux expériences dans un simulateur de conduite en réalité virtuelle. Les résultats montrent que les automobilistes utilisaient la taille et type de véhicules croisés pour réaliser les deux tâches