Exploration of the rotational power consumption of a rigid flapping wing

Accepted versio

Phosphate Starvation Triggers Production and Secretion of an Extracellular Lipoprotein in Caulobacter crescentus

Life in oligotrophic environments necessitates quick adaptive responses to a sudden lack of nutrients. Secretion of specific degradative enzymes into the extracellular medium is a means to mobilize the required nutrient from nearby sources. The aquatic bacterium Caulobacter crescentus must often face changes in its environment such as phosphate limitation. Evidence reported in this paper indicates that under phosphate starvation, C. crescentus produces a membrane surface-anchored lipoprotein named ElpS subsequently released into the extracellular medium. A complete set of 12 genes encoding a type II secretion system (T2SS) is located adjacent to the elpS locus in the C. crescentus genome. Deletion of this T2SS impairs release of ElpS in the environment, which surprisingly remains present at the cell surface, indicating that the T2SS is not involved in the translocation of ElpS to the outer membrane but rather in its release. Accordingly, treatment with protease inhibitors prevents release of ElpS in the extracellular medium suggesting that ElpS secretion relies on a T2SS-secreted protease. Finally, secretion of ElpS is associated with an increase in alkaline phosphatase activity in culture supernatants, suggesting a role of the secreted protein in inorganic phosphate mobilization. In conlusion, we have shown that upon phosphate starvation, C. crescentus produces an outer membrane bound lipoprotein, ElpS, which is further cleaved and released in the extracellular medium in a T2SS-dependent manner. Our data suggest that ElpS is associated with an alkaline phosphatase activity, thereby allowing the bacterium to gather inorganic phosphates from a poor environment

RhoGTPase Regulators Orchestrate Distinct Stages of Synaptic Development

Small RhoGTPases regulate changes in post-synaptic spine morphology and density that support learning and memory. They are also major targets of synaptic disorders, including Autism. Here we sought to determine whether upstream RhoGTPase regulators, including GEFs, GAPs, and GDIs, sculpt specific stages of synaptic development. The majority of examined molecules uniquely regulate either early spine precursor formation or later matura- tion. Specifically, an activator of actin polymerization, the Rac1 GEF β-PIX, drives spine pre- cursor formation, whereas both FRABIN, a Cdc42 GEF, and OLIGOPHRENIN-1, a RhoA GAP, regulate spine precursor elongation. However, in later development, a novel Rac1 GAP, ARHGAP23, and RhoGDIs inactivate actomyosin dynamics to stabilize mature synap- ses. Our observations demonstrate that specific combinations of RhoGTPase regulatory pro- teins temporally balance RhoGTPase activity during post-synaptic spine development

Proceedings of the Fifth Italian Conference on Computational Linguistics CLiC-it 2018

On behalf of the Program Committee, a very warm welcome to the Fifth Italian Conference on Computational Linguistics (CLiC-­‐it 2018). This edition of the conference is held in Torino. The conference is locally organised by the University of Torino and hosted into its prestigious main lecture hall “Cavallerizza Reale”. The CLiC-­‐it conference series is an initiative of the Italian Association for Computational Linguistics (AILC) which, after five years of activity, has clearly established itself as the premier national forum for research and development in the fields of Computational Linguistics and Natural Language Processing, where leading researchers and practitioners from academia and industry meet to share their research results, experiences, and challenges

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Real-time auralization of industrial noise

A real-time and interactive auralization system has been developed within the research project Auralias (www.auralias.be). Originally conceived for architectural acoustics applications, this system is now applied to auralize the effect of noise reduction solutions in industrial halls. Some specific characters of this kind of problems are first identified: several sources with intermittent noise emission, rectangular hall geometries, quite reverberant spaces, sound level calibration needed. A protocol for the application of the auralizer is then tested on an example, from the room acoustics model to the final sound rendering.AURALIA

Constraints on the design of core-shell resonators of locally resonant acoustic metamaterials

We perform a parametric study of the analytic model of Liu et al. [ Z. Liu et al. Phys. Rev. B 71 014103 (2005)] describing the mechanical response of a core-shell particle to an acoustic excitation in order to help in selecting the constitutive materials and in designing innovative processes of fabrication of downsized core-shell resonators, which are key constituents of locally resonant acoustic metamaterials. We show that the value of the first Lamé coefficient of the material constituting the shell has no marked influence on the value of the resonance frequency of the core-shell resonator, that is, it does not necessarily need to be small for satisfying the condition of subwavelength resonator dimension at resonance. Moreover, we show that the larger the density contrast between the core and the shell and the thinner the shell, the broader is the frequency band over which the effective density of the resonator suspension is negative, but that it is practically useless to decrease the dimensionless shell thickness below 0.6. Finally, we show that the dissipation is also less perceptible the thinner is the shell and the larger is the density contrast. The effect of the density contrast between the core and the shell and of the dissipation on the resonance width are explained by comparing with the harmonic oscillator and the mass-in-mass 1D lattice.Approche rationnelle pour la réalisation de métamatériaux pour l'acoustique ultrasonor

Caractérisation acoustique des parois épaisses périodiques dans les locaux industriels

Les parois qui délimitent les locaux industriels peuvent présenter un relief périodique. Différentes méthodes dédiées à la caractérisation acoustique de ce type de parois, encore appelées réseaux acoustiques, sont présentées. L'une d'entre elle, la méthode des guides d'ondes, s'est révélée particulièrement bien adaptée aux géométries couramment rencontrées dans les locaux industriels. Cette méthode consiste à discrétiser les profils des réseaux acoustiques en éléments géométriques simples et à rechercher le champ acoustique dans les régions associées à chacun de ces éléments sous la forme d'ondes guidées. Des simulations numériques de la méthode des guides d'ondes ont été réalisées afin de mettre en évidence certains phénomènes physiques associés aux réseaux acoustiques. La méthode des guides d'ondes a également été comparée à d'autres méthodes existantes. Une généralisation de cette méthode a ensuite été développée, afin d'en étendre le domaine d'application aux réseaux acoustiques deux fois périodiques. Une campagne de mesures en champ libre a également été mise en œuvre. La bonne concordance entre les résultats numériques et expérimentaux a permis de mettre en évidence la pertinence de la méthode des guides d'ondes.Facings in industrial rooms can have periodic profiles. Various methods for the acoustic characterization of those kind of facings are presented in this work. The waveguides method, is well adapted to the geometries usually met in industrial rooms. According to this method, the profile geometry is simplified using elementary rectangular volumes. The acoustic field in the profile interstices can then be expressed as the superposition of waveguide modes. Numerical simulations of the waveguides method were realized, and physical phenomena associated with the sound reflection on periodic facings were observed. The waveguides method was also numerically compared with other existing methods. A generalization of this method have been proposed to extend its applicability to twice-periodic facings. Free field measurements were also carried out. The agreement between numerical and experimental results proves that the waveguides method is valid.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF