283 research outputs found
Motion Capture System for Finger Movement Measurement in Parkinson Disease
Parkinson’s disease (PD) is a chronic neurodegenerative disorder that affects almost 1% of the population in the age group above 60 years. The key symptom in PD is the restriction of mobility. The progress of PD is typically documented using the Unified Parkinson’s Disease Rating Scale (UPDRS), which includes a finger-tapping test. We created a measurement tool and a methodology for the objective measurement of the finger-tapping test. We built a contactless three-dimensional (3D) capture system using two cameras and light-passive (wireless) reflexive markers. We proposed and implemented an algorithm for extracting, matching, and tracing markers. The system provides the 3D position of spherical or hemispherical markers in real time. The system’s functionality was verified with the commercial motion capture system OptiTrack. Our motion capture system is easy to use, saves space, is transportable, and needs only a personal computer for data processing—the ideal solution for an outpatient clinic. Its features were successfully tested on 22 patients with PD and 22 healthy control subjects
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Van Hove Singularity and Superconductivity in Disordered Hubbard Model
We apply the Coherent Potential Approximation (CPA) to a simple extended
Hubbard model with a nearest and next nearest neighbour hopping for disordered
superconductors with s-, d- and p-wave pairing. We show how the Van Hove
singularities in the electron density of states enhance the transition
temperature Tc for exotic superconductors in a clean and weakly disordered
system. The Anderson theorem and pair-breaking effects in presence of Van Hove
singularity caused by non-magnetic disorder are also discussed.Comment: REVTEX 40 pages, 8 figures, (accepted by Physica Status Solidi b
L’intelligence économique territoriale
Cette recherche se propose de comprendre comment le management public va annihiler le bon fonctionnement d’une communauté stratégique de connaissance autour d’un dispositif d’intelligence économique territoriale. Au travers d’une étude de cas issue d’une recherche-action entreprise depuis 2005, nous montrons comment une liste d’entreprises stratégiques va subir la transformation d’« objet frontière » en « objet barrière » sous la contrainte d’une lettre de cadrage de l’État dans une logique descendante de l’action publique typique du renforcement d’un phénomène bureaucratique. Enfin, nous explicitons les raisons du passage d’une volonté d’utopie des territoires en territoires des utopies, par l’absence de rencontre entre logique ascendante et descendante de la politique publique d’intelligence économique territoriale.This research aims to understand how public management will destroy the functioning of a «strategic knowledge community» build around of a territorial competitive intelligence device. Through a case study issue from a participatory action research conducted since 2005, we show how a list of strategic companies will be transform from a «boundary object» to a «barrier object» under the constraint of French State directive in a top-down logic which is typical of public management that reinforce the bureaucratic phenomenon in society. Finally, we explain the reasons of the switch for the desire for an utopia for territories to the territories of utopias by the lack of contact between bottom-up and top-down public policy of territorial competitive intelligence
Reshaping cortical activity with subthalamic stimulation in Parkinson's disease during finger tapping and gait mapped by near infrared spectroscopy
Exploration of motor cortex activity is essential to understanding the pathophysiology in Parkinson's Disease (PD), but only simple motor tasks can be investigated using a fMRI or PET. We aim to investigate the cortical activity of PD patients during a complex motor task (gait) to verify the impact of deep brain stimulation in the subthalamic nucleus (DBS-STN) by using Near-Infrared-Spectroscopy (NIRS). NIRS is a neuroimaging method of brain cortical activity using low-energy optical radiation to detect local changes in (de)oxyhemoglobin concentration. We used a multichannel portable NIRS during finger tapping (FT) and gait. To determine the signal activity, our methodology consisted of a pre-processing phase for the raw signal, followed by statistical analysis based on a general linear model. Processed recordings from 9 patients were statistically compared between the on and off states of DBS-STN. DBS-STN led to an increased activity in the contralateral motor cortex areas during FT. During gait, we observed a concentration of activity towards the cortex central area in the "stimulation-on" state. Our study shows how NIRS can be used to detect functional changes in the cortex of patients with PD with DBS-STN and indicates its future use for applications unsuited for PET and a fMRI
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