Towards generic satellite payloads: software radio

Satellite payloads are becoming much more complex with the evolution towards multimedia applications. Moreover satellite lifetime increases while standard and services evolve faster, necessitating a hardware platform that can evolves for not developing new systems on each change. The same problem occurs in terrestrial systems like mobile networks and a foreseen solution is the software defined radio technology. In this paper we describe a way of introducing this concept at satellite level to offer to operators the required flexibility in the system. The digital functions enabling this technology, the hardware components implementing the functions and the reconfiguration processes are detailed. We show that elements of the software radio for satellites exist and that this concept is feasible

Être catéchiste : témoigner d’une expérience. Enquêtes auprès des catéchistes en Belgique (Vicariats de Bruxelles et du Brabant wallon) et en France (Diocèses de Nanterre et Créteil)

La première partie de l’ouvrage rend compte des résultats de l’enquête belge menée par le Centre universitaire de théologie pratique (UCL) auprès de personnes engagées en catéchèse dans la partie francophone du diocèse de Malines-Bruxelles entre novembre 2012 et janvier 2013. Il est rendu compte des constats qui se dégagent de 337 réponses reçues et des résultats de l’analyse statistique des données récoltées. La deuxième partie de l’ouvrage présente les résultats de l’enquête française, fruit d'un travail réalisé au cours de l'année universitaire 2013-2014 à l'Institut Supérieur de Pastorale Catéchétique (ICP) dans les diocèses de de Créteil et de Nanterre. 44 personnes ont été rencontrées. Les entretiens ont fait l'objet d'un double dépouillement : l'un à partir de relectures collectives pour repérer comment se construisait une identité de catéchistes, l'autre par informatique. La troisième partie de l’ouvrage s’arrête aux convergences qui se dégagent des deux enquêtes, en particulier en ce qui concerne le rapport entre expérience et doctrine, la relation aux enfants, aux parents, à l’institution ecclésiale et le rapport des catéchistes à leur expérience catéchétique

MMN and Novelty P3 in Coma and Other Altered States of Consciousness: A Review.

International audienceIn recent decades, there has been a growing interest in the assessment of patients in altered states of consciousness. There is a need for accurate and early prediction of awakening and recovery from coma. Neurophysiological assessment of coma was once restricted to brainstem auditory and primary cortex somatosensory evoked potentials elicited in the 30 ms range, which have both shown good predictive value for poor coma outcome only. In this paper, we review how passive auditory oddball paradigms including deviant and novel sounds have proved their efficiency in assessing brain function at a higher level, without requiring the patient's active involvement, thus providing an enhanced tool for the prediction of coma outcome. The presence of an MMN in response to deviant stimuli highlights preserved automatic sensory memory processes. Recorded during coma, MMN has shown high specificity as a predictor of recovery of consciousness. The presence of a novelty P3 in response to the subject's own first name presented as a novel (rare) stimulus has shown a good correlation with coma awakening. There is now a growing interest in the search for markers of consciousness, if there are any, in unresponsive patients (chronic vegetative or minimally conscious states). We discuss the different ERP patterns observed in these patients. The presence of novelty P3, including parietal components and possibly followed by a late parietal positivity, raises the possibility that some awareness processes are at work in these unresponsive patients

Attention orienting dysfunction with preserved automatic auditory change detection in migraine.

International audienceOBJECTIVE:To investigate automatic event-related potentials (ERPs) to an auditory change in migraine patients.METHODS:Auditory ERPs were recorded in 22 female patients suffering from menstrually-related migraine and in 20 age-matched control subjects, in three sessions: in the middle of the menstrual cycle, before and during menses. In each session, 200 trains of tone-bursts each including two duration deviants were presented in a passive listening condition.RESULTS:In all sessions, duration deviance elicited a mismatch negativity (MMN) showing no difference between the two groups. However, migraine patients showed an increased N1 orienting component to all incoming stimuli and a prolonged N2b to deviance. They also presented a different modulation of P3a amplitude along the menstrual cycle, which tended to normalise during migraine attacks. None of the studied ERP components showed a default of habituation.CONCLUSIONS:This passive paradigm highlighted increased automatic attention orienting to auditory changes but normal auditory sensory processing in migraineurs.SIGNIFICANCE:Our observations suggest normal auditory processing up to attention triggering but enhanced activation of attention-related frontal networks in migraineurs

Infraclinical detection of voluntary attention in coma and post-coma patients using electrophysiology

International audienceOBJECTIVE: Early functional evaluation and prognosis of patients with disorders of consciousness is a major challenge that clinical assessments alone cannot solve. Objective measures of brain activity could help resolve this uncertainty. We used electroencephalogram at bedside to detect voluntary attention with a paradigm previously validated in healthy subjects. METHODS: Using auditory-oddball sequences, our approach rests on detecting known attentional modulations of Event Related Potentials that reflect compliance with verbal instructions. Sixty-eight unresponsive patients were tested in their first year after coma onset (37 coma and 31 first year post-coma patients). Their evolution 6 months after the test was considered. RESULTS: Fourteen of the 68 patients, showed a positive response. Nine were in a coma and 5 in a minimally conscious state (MCS). Except for one who died early, all responders evolved to exit-MCS within 6 months (93%), while 35 (65%) among non-responders only. CONCLUSIONS: Among those patients for whom the outcome is highly uncertain, 21% responded positively to this simple but cognitively demanding test. Strikingly, some coma patients were among responders. SIGNIFICANCE: The proposed paradigm revealed cognitive-motor dissociation in some coma patients. This ability to sustain attention on demand predicted awakening within 6 months and represents an immediately useful information for relatives and caregivers