Silicon on Nothing Mems Electromechanical Resonator

The very significant growth of the wireless communication industry has spawned tremendous interest in the development of high performances radio frequencies (RF) components. Micro Electro Mechanical Systems (MEMS) are good candidates to allow reconfigurable RF functions such as filters, oscillators or antennas. This paper will focus on the MEMS electromechanical resonators which show interesting performances to replace SAW filters or quartz reference oscillators, allowing smaller integrated functions with lower power consumption. The resonant frequency depends on the material properties, such as Young's modulus and density, and on the movable mechanical structure dimensions (beam length defined by photolithography). Thus, it is possible to obtain multi frequencies resonators on a wafer. The resonator performance (frequency, quality factor) strongly depends on the environment, like moisture or pressure, which imply the need for a vacuum package. This paper will present first resonator mechanisms and mechanical behaviors followed by state of the art descriptions with applications and specifications overview. Then MEMS resonator developments at STMicroelectronics including FEM analysis, technological developments and characterization are detailed.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Ouvrir plus, ouvrir mieux

L’Agence régionale du livre PACA et l’enssib proposent une journée professionnelle consacrée à l’amélioration de la facilité d’accès aux bibliothèques. Ce thème anime la profession depuis une dizaine d’années et est étayé par des études montrant la mutation du rapport de l’usager à la bibliothèque. Ce changement de comportement individuel peut s’observer sous les angles de la gestion du temps social et l’aménagement des temps urbains

L’intérêt de la méthode Mckenzie dans le traitement des cervicalgies

Context and goal: In a context where there is no real consensus on the classification and treatment of neck pain, Robin McKenzie has brought a new tool. This tool is now scientifically recognized in the treatment of low back pain. However, there is very little literature on neck pain.Therefore, the aim of this review is to determine the potential value of the McKenzie method in the management of patients with neck pain, in particular its effect on the pain felt by patients and their functional disability.Method: Searches were conducted using databases such as PubMed, PEDro and Cochrane. The studies compared the Mckenzie method to different existing rehabilitation protocols. Studies were selected according to their methodologies and PICO criteria.Result: Four studies were included. Two studies showed significant results on short-term pain reduction. However, the other data collected were not statistically significant. The heterogeneity of the studied populations, the methodological differences between the studies and the various comparators used limited the analyses in this review. Discussion/conclusion: These collected results show a certain tendency in favour of the MDT protocol. However, it is impossible to conclude that the MDT method provides better pain and disability management than other protocols. The weakness of these results needs to be confronted with its clinical implementation, which seems to be a practical and cost-effective solution.Contexte et objectif : dans un contexte où la classification et les traitements des cervicalgies n’ont trouvé aucun consensus réel, Robin McKenzie a apporté un nouvel outil. Cet outil est maintenant reconnu scientifiquement dans le traitement des lombalgies. Toutefois, il existe très peu de littérature concernant les cervicalgies.C’est pourquoi, l’objectif de cette revue est de déterminer les intérêts que peut représenter la méthode Mckenzie dans la prise en charge des patients atteints de cervicalgies, notamment son effet sur la douleur ressentie par les patients et leur incapacité fonctionnelle.Méthode : les recherches ont été effectuées à partir de bases de données telles que : PubMed, PEDro et Cochrane. Les études comparaient la méthode Mckenzie à différents protocoles de rééducation déjà existants. La sélection des études a été réalisée selon leurs méthodologies et des critères PICO.Résultat : quatre études ont été incluses. Deux études ont révélé des résultats significatifs sur la diminution de la douleur à court terme. Cependant, les autres données récoltées ne se sont pas montrées statistiquement significatives. L’hétérogénéité des populations étudiées, les différences méthodologiques entres les études et les divers comparateurs utilisés ont limité les analyses de cette revue.Discussion/conclusion : ces résultats récoltés permettent de mettre en lumière une certaine tendance en faveur du protocole MDT. Cependant, il est impossible de conclure que la méthode MDT permette une meilleure gestion de la douleur ainsi qu’une meilleure prise en charge de l’incapacité par rapport aux autres protocoles. La faiblesse de ces résultats mérite d’être confrontée à sa mise en application clinique, qui semble être une solution pratique et rentable

Ouvrir plus

Table ronde organisée dans le cadre de la journée d\u27étude "Ouvrir plus, ouvrir mieux". Avec la participation de : - Rémi Borel, directeur de la Bibliothèque Méjanes, Aix-en-Provence. - Louis Burle, conseiller pour le Livre et la Lecture, DRAC PACA. - Emmanuelle Kalfa, directrice de la médiathèque de Lomme (Nord). Modération : Georges Perrin, inspecteur général honoraire des bibliothèques

SILICON ON NOTHING MEMS ELECTROMECHANICAL RESONATOR

International audienceThe very significant growth of the wireless communication industry has spawned tremendous interest in the development of high performances radio frequencies (RF) components. Micro Electro Mechanical Systems (MEMS) are good candidates to allow reconfigurable RF functions such as filters, oscillators or antennas. This paper will focus on the MEMS electromechanical resonators which show interesting performances to replace SAW filters or quartz reference oscillators, allowing smaller integrated functions with lower power consumption. The resonant frequency depends on the material properties, such as Young's modulus and density, and on the movable mechanical structure dimensions (beam length defined by photolithography). Thus, it is possible to obtain multi frequencies resonators on a wafer. The resonator performance (frequency, quality factor) strongly depends on the environment, like moisture or pressure, which imply the need for a vacuum package. This paper will present first resonator mechanisms and mechanical behaviors followed by state of the art descriptions with applications and specifications overview. Then MEMS resonator developments at STMicroelectronics including FEM analysis, technological developments and characterization are detailed

Maximal amenable subalgebras arising from maximal amenable subgroups

We provide a general criterion to deduce maximal amenability of von Neumann subalgebras LΛ ⊂ LΓ arising from amenable subgroups Λ of discrete countable groups Γ. The criterion is expressed in terms of Λ-invariant measures on some compact Γ-space. The strategy of proof is different from S. Popa's approach to maximal amenability via central sequences [Po83], and relies on elementary computations in a crossed-product C *-algebra

High Risk of Anal and Rectal Cancer in Patients With Anal and/or Perianal Crohn’s Disease

International audienceBackground & AimsLittle is known about the magnitude of the risk of anal and rectal cancer in patients with anal and/or perineal Crohn’s disease. We aimed to assess the risk of anal and rectal cancer in patients with Crohn’s perianal disease followed up in the Cancers Et Surrisque Associé aux Maladies Inflammatoires Intestinales En France (CESAME) cohort.MethodsWe collected data from 19,486 patients with inflammatory bowel disease (IBD) enrolled in the observational CESAME study in France, from May 2004 through June 2005; 14.9% of participants had past or current anal and/or perianal Crohn’s disease. Subjects were followed up for a median time of 35 months (interquartile range, 29–40 mo). To identify risk factors for anal cancer in the total CESAME population, we performed a case-control study in which participants were matched for age and sex.ResultsAmong the total IBD population, 8 patients developed anal cancer and 14 patients developed rectal cancer. In the subgroup of 2911 patients with past or current anal and/or perianal Crohn’s lesions at cohort entry, 2 developed anal squamous-cell carcinoma, 3 developed perianal fistula–related adenocarcinoma, and 6 developed rectal cancer. The corresponding incidence rates were 0.26 per 1000 patient-years for anal squamous-cell carcinoma, 0.38 per 1000 patient-years for perianal fistula–related adenocarcinoma, and 0.77 per 1000 patient-years for rectal cancer. Among the 16,575 patients with ulcerative colitis or Crohn’s disease without anal or perianal lesions, the incidence rate of anal cancer was 0.08 per 1000 patient-years and of rectal cancer was 0.21 per 1000 patient-years. Among factors tested by univariate conditional regression (IBD subtype, disease duration, exposure to immune-suppressive therapy, presence of past or current anal and/or perianal lesions), the presence of past or current anal and/or perianal lesions at cohort entry was the only factor significantly associated with development of anal cancer (odds ratio, 11.2; 95% CI, 1.18-551.51; P = .03).ConclusionsIn an analysis of data from the CESAME cohort in France, patients with anal and/or perianal Crohn’s disease have a high risk of anal cancer, including perianal fistula–related cancer, and a high risk of rectal cancer