Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly progress report no. 11, Mar. 1966

Breadboard model development of integrated static inverte

Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly report no. 15

Flip-flop arrays, power transistors, epitaxial stress, and other technological developments in integrated static inverter progra

Oscillation threshold of a clarinet model: a numerical continuation approach

This paper focuses on the oscillation threshold of single reed instruments. Several characteristics such as blowing pressure at threshold, regime selection, and playing frequency are known to change radically when taking into account the reed dynamics and the flow induced by the reed motion. Previous works have shown interesting tendencies, using analytical expressions with simplified models. In the present study, a more elaborated physical model is considered. The influence of several parameters, depending on the reed properties, the design of the instrument or the control operated by the player, are studied. Previous results on the influence of the reed resonance frequency are confirmed. New results concerning the simultaneous influence of two model parameters on oscillation threshold, regime selection and playing frequency are presented and discussed. The authors use a numerical continuation approach. Numerical continuation consists in following a given solution of a set of equations when a parameter varies. Considering the instrument as a dynamical system, the oscillation threshold problem is formulated as a path following of Hopf bifurcations, generalizing the usual approach of the characteristic equation, as used in previous works. The proposed numerical approach proves to be useful for the study of musical instruments. It is complementary to analytical analysis and direct time-domain or frequency-domain simulations since it allows to derive information that is hardly reachable through simulation, without the approximations needed for analytical approach

Physics of wind instruments an overview of studies carried out at LMA

International audienceA poster is presented with the aim of doing an overview of the research activities carried out on the physics of wind instruments at the Laboratory of Mechanics and Acoustic

Contribution to harmonic balance calculations of self-sustained periodic oscillations with focus on single-reed instruments

International audienceThe harmonic balance method ͑HBM͒ was originally developed for finding periodic solutions of electronical and mechanical systems under a periodic force, but has been adapted to self-sustained musical instruments. Unlike time-domain methods, this frequency-domain method does not capture transients and so is not adapted for sound synthesis. However, its independence of time makes it very useful for studying any periodic solution, whether stable or unstable, without care of particular initial conditions in time. A computer program for solving general problems involving nonlinearly coupled exciter and resonator, HARMBAL, has been developed based on the HBM. The method as well as convergence improvements and continuation facilities are thoroughly presented and discussed in the present paper. Applications of the method are demonstrated, especially on problems with severe difficulties of convergence: the Helmholtz motion ͑square signals͒ of single-reed instruments when no losses are taken into account, the reed being modeled as a simple spring

Tracheostomy in the COVID-19 era: global and multidisciplinary guidance

Global health care is experiencing an unprecedented surge in the number of critically ill patients who require mechanical ventilation due to the COVID-19 pandemic. The requirement for relatively long periods of ventilation in those who survive means that many are considered for tracheostomy to free patients from ventilatory support and maximise scarce resources. COVID-19 provides unique challenges for tracheostomy care: health-care workers need to safely undertake tracheostomy procedures and manage patients afterwards, minimising risks of nosocomial transmission and compromises in the quality of care. Conflicting recommendations exist about case selection, the timing and performance of tracheostomy, and the subsequent management of patients. In response, we convened an international working group of individuals with relevant expertise in tracheostomy. We did a literature and internet search for reports of research pertaining to tracheostomy during the COVID-19 pandemic, supplemented by sources comprising statements and guidance on tracheostomy care. By synthesising early experiences from countries that have managed a surge in patient numbers, emerging virological data, and international, multidisciplinary expert opinion, we aim to provide consensus guidelines and recommendations on the conduct and management of tracheostomy during the COVID-19 pandemic

Features of Mild-to-Moderate COVID-19 Patients with Dysphonia

Introduction To explore the prevalence of dysphonia in European patients with mild-to-moderate COVID-19 and the clinical features of dysphonic patients. Methods The clinical and epidemiological data of 702 patients with mild-to-moderate COVID-19 were collected from 19 European Hospitals. The following data were extracted: age, sex, ethnicity, tobacco consumption, comorbidities, general and otolaryngological symptoms. Dysphonia and otolaryngological symptoms were self-assessed through a 4-point scale. The prevalence of dysphonia, as part of the COVID-19 symptoms, was assessed. The outcomes were compared between dysphonic and non-dysphonic patients. The association between dysphonia severity and outcomes was studied through Bayesian analysis. Results A total of 188 patients were dysphonic, accounting for 26.8% of cases. Females developed more frequently dysphonia than males (p=0.022). The proportion of smokers was significantly higher in the dysphonic group (p=0.042). The prevalence of the following symptoms was higher in dysphonic patients compared with non-dysphonic patients: cough, chest pain, sticky sputum, arthralgia, diarrhea, headache, fatigue, nausea and vomiting. The severity of dyspnea, dysphagia, ear pain, face pain, throat pain and nasal obstruction was higher in dysphonic group compared with non-dysphonic group. There were significant associations between the severity of dysphonia, dysphagia and cough. Conclusion Dysphonia may be encountered in a quarter of patients with mild-to-moderate COVID-19 and should be considered as a symptom list of the infection. Dysphonic COVID-19 patients are more symptomatic than non-dysphonic individuals. Future studies are needed to investigate the relevance of dysphonia in the COVID-19 clinical presentation

«La relation de limitation et d’exception dans le français d’aujourd’hui : excepté, sauf et hormis comme pivots d’une relation algébrique »

L’analyse des emplois prépositionnels et des emplois conjonctifs d’ “excepté”, de “sauf” et d’ “hormis” permet d’envisager les trois prépositions/conjonctions comme le pivot d’un binôme, comme la plaque tournante d’une structure bipolaire. Placées au milieu du binôme, ces prépositions sont forcées par leur sémantisme originaire dûment métaphorisé de jouer le rôle de marqueurs d’inconséquence systématique entre l’élément se trouvant à leur gauche et celui qui se trouve à leur droite. L’opposition qui surgit entre les deux éléments n’est donc pas une incompatibilité naturelle, intrinsèque, mais extrinsèque, induite. Dans la plupart des cas (emplois limitatifs), cette opposition prend la forme d’un rapport entre une « classe » et le « membre (soustrait) de la classe », ou bien entre un « tout » et une « partie » ; dans d’autres (emplois exceptifs), cette opposition se manifeste au contraire comme une attaque de front portée par un « tout » à un autre « tout ». De plus, l’inconséquence induite mise en place par la préposition/conjonction paraît, en principe, tout à fait insurmontable. Dans l’assertion « les écureuils vivent partout, sauf en Australie » (que l’on peut expliciter par « Les écureuils vivent partout, sauf [qu’ils ne vivent pas] en Australie »), la préposition semble en effet capable d’impliquer le prédicat principal avec signe inverti, et de bâtir sur une telle implication une sorte de sous énoncé qui, à la rigueur, est totalement inconséquent avec celui qui le précède (si « les écureuils ne vivent pas en Australie », le fait qu’ils « vivent partout » est faux). Néanmoins, l’analyse montre qu’alors que certaines de ces oppositions peuvent enfin être dépassées, d’autres ne le peuvent pas. C’est, respectivement, le cas des relations limitatives et des relations exceptives. La relation limitative, impliquant le rapport « tout » - « partie », permet de résoudre le conflit dans les termes d’une somme algébrique entre deux sous énoncés pourvus de différent poids informatif et de signe contraire. Les valeurs numériques des termes de la somme étant déséquilibrées, le résultat est toujours autre que zéro. La relation exceptive, au contraire, qui n’implique pas le rapport « tout » - « partie », n’est pas capable de résoudre le conflit entre deux sous énoncés pourvus du même poids informatif et en même temps de signe contraire : les valeurs numériques des termes de la somme étant symétriques et égales, le résultat sera toujours équivalent à zéro

A dual role for the N-terminal domain of the IL-3 receptor in cell signalling

The interleukin-3 (IL-3) receptor is a cell-surface heterodimer that links the haemopoietic, vascular and immune systems and is overexpressed in acute and chronic myeloid leukaemia progenitor cells. It belongs to the type I cytokine receptor family in which the α-subunits consist of two fibronectin III-like domains that bind cytokine, and a third, evolutionarily unrelated and topologically conserved, N-terminal domain (NTD) with unknown function. Here we show by crystallography that, while the NTD of IL3Rα is highly mobile in the presence of IL-3, it becomes surprisingly rigid in the presence of IL-3 K116W. Mutagenesis, biochemical and functional studies show that the NTD of IL3Rα regulates IL-3 binding and signalling and reveal an unexpected role in preventing spontaneous receptor dimerisation. Our work identifies a dual role for the NTD in this cytokine receptor family, protecting against inappropriate signalling and dynamically regulating cytokine receptor binding and function.Sophie E. Broughton, Timothy R. Hercus, Tracy L. Nero, Winnie L. Kan ... Timothy P. Hughes, Angel F. Lopez ... et al