How far can the resonance frequencies give informations about the playing frequencies? The trumpet example

International audienceMeasurements and calculations of the input impedance of wind musical instruments are now well mastered. The purpose of this work is to study experimentally how far the resonance frequencies of brass instruments, taken from their input impedance, are able to give informations about the playing frequencies. Three different trumpets, obtained by changing only the leadpipe of the same instrument, were considered for the experiment. After a measurement of the input impedance of these trumpets, four musicians were asked to play the five first playable notes (regimes 2 to 6), for four different fingerings. This exercise was done for three nuances and was repeated three times. Finally, these 3×4×5×4×3×3=2160 notes allow us to make a quantitative assessment of the relations between the resonance frequencies and the playing frequencies. Results show first, a limited influence of the musician on the overall intonation of the instrument. Second, the pitch of the notes does not vary much with the nuances. Finally, the results confirm the fact that variations of the resonance frequencies lead to variations of the playing frequencies of the same order

Two Chromogranin A-Derived Peptides Induce Calcium Entry in Human Neutrophils by Calmodulin-Regulated Calcium Independent Phospholipase A2

Background: Antimicrobial peptides derived from the natural processing of chromogranin A (CgA) are co-secreted with catecholamines upon stimulation of chromaffin cells. Since PMNs play a central role in innate immunity, we examine responses by PMNs following stimulation by two antimicrobial CgA-derived peptides. Methodology/Principal Findings: PMNs were treated with different concentrations of CgA-derived peptides in presence of several drugs. Calcium mobilization was observed by using flow cytometry and calcium imaging experiments. Immunocytochemistry and confocal microscopy have shown the intracellular localization of the peptides. The calmodulin-binding and iPLA2 activating properties of the peptides were shown by Surface Plasmon Resonance and iPLA2 activity assays. Finally, a proteomic analysis of the material released after PMNs treatment with CgA-derived peptides was performed by using HPLC and Nano-LC MS-MS. By using flow cytometry we first observed that after 15 s, in presence of extracellular calcium, Chromofungin (CHR) or Catestatin (CAT) induce a concentration-dependent transient increase of intracellular calcium. In contrast, in absence of extra cellular calcium the peptides are unable to induce calcium depletion from the stores after 10 minutes exposure. Treatment with 2-APB (2-aminoethoxydiphenyl borate), a store operated channels (SOCs) blocker, inhibits completely the calcium entry, as shown by calcium imaging. We also showed that they activate iPLA2 as the two CaM-binding factors (W7 and CMZ) and that the two sequences can be aligned with the two CaMbinding domains reported for iPLA2. We finally analyzed by HPLC and Nano-LC MS-MS the material released by PMNs following stimulation by CHR and CAT. We characterized several factors important for inflammation and innate immunity. Conclusions/Significance: For the first time, we demonstrate that CHR and CAT, penetrate into PMNs, inducing extracellular calcium entry by a CaM-regulated iPLA2 pathway. Our study highlights the role of two CgA-derived peptides in the active communication between neuroendocrine and immune systems

Les éruptions volcaniques de la Montagne Pelée et le premier peuplement de la Martinique.

International audienceLa Montagne Pelée doit lʼessentiel de sa renommée à la nuée ardente du 8 mai 1902 qui détruisit la ville de Saint-Pierre. Cependant, bien avant cette date ses éruptions avaient joué un rôle important dans la vie des premiers martiniquais. Face à cette réalité, il ne nous paraissait pas convenable dʼentreprendre lʼétude du peuplement amérindien de lʼîle sans prendre en compte la dimension volcanique. Ainsi, différents chercheurs du GDR 1122 du CNRS « Hommes et Volcans avant lʼHistoire » sont associés au projet collectif de recherche « Le Néolithique martiniquais dans son contexte antillais ». Les résultats que nous présentons ici sʼappuient sur lʼanalyse de cinq sites amérindiens situés sur les pourtours de la Montagne Pelée où les travaux de terrain ont permis de mettre au jour une intéressante interstratification des niveaux dʼoccupation précolombiens et des couches éruptives. Lʼétude que nous avons menée sʼarticule autour de deux objectifs principaux : - premièrement, nous avons cherché à distinguer et à caler chronologiquement les différents épisodes volcaniques contemporains de lʼoccupation précolombienne de lʼîle, - deuxièmement, nous tenté de percevoir lʼinfluence de ces phénomènes volcaniques sur les populations amérindiennes. Les résultats obtenus permettent de mieux concevoir la dynamique et la chronologie du peuplement précolombien de la Martinique

Oversampled filter banks as error correcting codes: Theory and impulse noise correction

Oversampled filter banks (OFBs) provide an overcomplete representation of their input signal. This paper describes how OFBs can be considered as error-correcting codes acting on real or complex sequences, very much like classical binary convolutional codes act on binary sequences. The structured redundancy introduced by OFBs in subband signals can be used to increase robustness to noise. In this paper, we define the notions of code subspace, syndrome, and parity-check polynomial matrix for OFBs. Furthermore, we derive generic expressions for projection-based decoding, suitable for the case when a simple second-order model completely characterizes the noise incurred by subband signals. We also develop a nonlinear hypotheses-test based decoding algorithm for the case when the noise in subbands is constituted by a Gaussian background noise and impulsive errors (a model that adequately describes the action of both quantization noise and transmission errors). Simulation results show that the algorithm effectively removes the effect of impulsive errors occurring with a probability of 10(-3)

Usability evaluation of virtual reality interaction techniques for positioning and manoeuvring in reduced, manipulation-oriented environments

This paper introduces some novel interaction techniques based on the concepts of composite positioning and composite manoeuvring (described in the paper). In contrast with other previous proposals, these techniques have been designed and evaluated in the context of a user centred process. The results of this evaluation and some relevant findings for the field of human computer interaction are also described

Validation of a descriptor, the "sum function", related to "quality" and derived from the input impedance of wind instruments

cote interne IRCAM: Causse11aNone / NoneNational audienceThe quality of a musical instrument embraces many aspects such as tuning, ease of play, tone, etc. This study aims to validate the use of the sum function (SF) proposed by Wogram from the measurement of input impedance as a descriptor of quality. This work is part of a wider project, PAFI (Aid Platform for Instrumental Making), supported by the French National Agency of Research. To validate the choice of the SF, we created a family of trumpets made from a basic instrument for which the leadpipe will be slightly modified for each model. The SF was calculated for a range of selected frequencies from the measurement of the input impedance of these different trumpets. The next step was to ask musicians experts to play these instruments, to measure the playing frequencies, and to note their feedback about quality. These tests were supplemented by comparative tests carried out this time with the help of a robotic artificial mouth. The final step involved was to try to identify correlations between the SF and the results of various tests and propose correction factors to be made to the formula of the SF, related to the nuance or range for example

Supporting the participation in social life of frail older adults in a one-day clinic

Ageing is associated with an increasing risk to acquire limitations in the daily life activities which is associated with restrictions in the participation in social life. The traditional solutions to address this issue are mainly offered by the health care system, from home care, to hospital admission and in some cases institutionalization in nursing homes. They could be supported and somehow at least in part replaced by Information and Communication Technologies (ICT). Keep-In-Touch has been elaborated in this context as a touch-based assistive technology for the older adults. The development method combined user-centered design together with agile development. A six-month pilot study has been undertaken in a one-day clinic in order to efficiently support the development method and evaluate the operational feasibility of the project. First results are promising. The participants judge the system as an effective and simple intergenerational communication tool. They also expressed very positive judgments about the accessibility of the user interface. Consequently, the same approach should be adopted to enrich the system with new functionalities