Three-sphere low-Reynolds-number swimmer with a passive elastic arm

One of the simplest model swimmers at low Reynolds number is the three-sphere swimmer by Najafi and Golestanian. It consists of three spheres connected by two rods which change their lengths periodically in non-reciprocal fashion. Here we investigate a variant of this model in which one rod is periodically actuated while the other is replaced by an elastic spring. We show that the competition between the elastic restoring force and the hydrodynamic drag produces a delay in the response of the passive elastic arm with respect to the active one. This leads to non-reciprocal shape changes and self-propulsion. After formulating the equations of motion, we study their solutions qualitatively and numerically. The leading-order term of the solution is computed analytically. We then address questions of optimization with respect to both actuation frequency and swimmer\u2019s geometry. Our results can provide valuable conceptual guidance in the engineering of robotic microswimmers

Correspondence Between Cognitive and Audiological Evaluations Among the Elderly: A Preliminary Report of an Audiological Screening Model of Subjects at Risk of Cognitive Decline With Slight to Moderate Hearing Loss

Epidemiological studies show increasing prevalence rates of cognitive decline and hearing loss with age, particularly after the age of 65 years. These conditions are reported to be associated, although conclusive evidence of causality and implications is lacking. Nevertheless, audiological and cognitive assessment among elderly people is a key target for comprehensive and multidisciplinary evaluation of the subject's frailty status. To evaluate the use of tools for identifying older adults at risk of hearing loss and cognitive decline and to compare skills and abilities in terms of hearing and cognitive performances between older adults and young subjects, we performed a prospective cross-sectional study using supraliminal auditory tests. The relationship between cognitive assessment results and audiometric results was investigated, and reference ranges for different ages or stages of disease were determined. Patients older than 65 years with different degrees of hearing function were enrolled. Each subject underwent an extensive audiological assessment, including tonal and speech audiometry, Italian Matrix Sentence Test, and speech audiometry with logatomes in quiet. Cognitive function was screened and then verified by experienced clinicians using the Montreal Cognitive Assessment Score, the Geriatric Depression Scale, and further investigations in some. One hundred twenty-three subjects were finally enrolled during 2016-2019: 103 were >65 years of age and 20 were younger participants (as controls). Cognitive functions showed a correlation with the audiological results in post-lingual hearing-impaired patients, in particular in those affected by slight to moderate hearing loss and aged more than 70 years. Audiological testing can thus be useful in clinical assessment and identification of patients at risk of cognitive impairment. The study was limited by its sample size (CI 95%; CL 10%), strict dependence on language, and hearing threshold. Further investigations should be conducted to confirm the reported results and to verify similar screening models

Percutaneous endoscopic gastrostomy : methods and personal findingst

La voie d'entrée alternative idéale pour l'alimentation entérale doit être d'exécution simple, sûre, réversible, peu onéreuse et facile à gérer. La gastrostomie endoscopique percutanée (GEP) satisfait à ces conditions. Entre juillet 1989 et avril 1995, nous avons placé 254 prothèses endo-gastriques (PEG). Nous avons utilisé et comparé les techniques « pull, push et introducer » et des modèles différents de prothèses. Le taux de succès a été de 98,1 %. La durée moyenne de l'intervention a été de 12 minutes. Nous n'avons pas eu de décès et seulement trois complications graves (1,2 %): 1 hémorragie massive, 1 péritonite, 1 buried bumper syndrome. Les complications mineures (17,7 %) ont été: pneumopéritoine (1,2 %), infections péristomales (2,8 %), buried bumper syndrome (0,4 %), mécaniques (4,7 %), reflux gastro-oesophagien (3,5 %), diarrhée (4,7 %) et ralentissement de la vidange gastrique (0,4 %). L'extraordinaire succès rencontré par la méthode aux USA (où ont été mises en place plus d'1 000 000 de PEG et 310 000 kits vendus en 1994), a gagné l'Europe où en Allemagne et en Italie on été vendus respectivement 143 000 et 12 000 kits

Late cochlear implant in a prelingually hearing impaired subject: electrophysiological and audiometric improvement over time

Objectives: The aim of this study was to evaluate electrophysiological and audiological findings in a prelingually late implanted patient, in two consecutive follow-ups: 3 months after cochlear implant (CI) activation and 1 year later. Methods: As an electrophysiological evaluation, the event-related potentials (ERPs) N100, N200P300 were used. The P300 wave is an objective measure of the central auditory function. It reflects the cortical activity involved during attention, discrimination, memory, integration and decision-making skills and it is a measure of speech discrimination and linguistic recognition. Pure tone audiometry, speech perception tests and electrophysiological examination were performed at 3 and 15 months post-CI activation. Result and Discussion: The N100 and N200 latencies were very similar in both follow-ups, whereas P300 latency decreased significantly 15 months postactivation, reaching a value close to normality. This finding was related to an increase in audiometric and speech performances. Conclusion: A significant improvment in electrophysiological, audiometric and speech performances was observed during the second follow-up, underlining the great importance of the duration of device use, in spite of a late implant surgery. These simultaneous improvements can be related to a general increase of superior cognitive functions

Dizionario Biografico dell'Educazione (1800-2000)

Il Dizionario Biografico dell\u2019Educazione (DBE) presenta 2.346 profili biografici, frutto di originali e approfondite indagini archivistiche e di una sistematica valorizzazione dei risultati della pi\uf9 recente e qualificata storiografia educativa italiana e internazionale. Attraverso questa ricchezza documentaria, il Dizionario va a colmare l\u2019attuale carenza di rassegne biografiche organiche e aggiornate riguardanti il mondo di educatori, benefattori e filantropi, pedagogisti, uomini di scuola e scrittori per l\u2019infanzia e per la giovent\uf9. Per la prima volta accanto a tutti i pi\uf9 noti pedagogisti, istitutori e personalit\ue0 politiche di fama nazionale e internazionale, sono biografate anche le numerose e variegate figure dei nuovi \u201cprofessionisti dell\u2019educazione e della scuola\u201d prodotte dalla crescente espansione, a partire dai primi decenni dell\u2019Ottocento, dei processi di alfabetizzazione e di scolarizzazione di massa. Si tratta di una vasta e composita realt\ue0 di personaggi: fondatori e animatori di istituzioni scolastiche ed educative per l\u2019infanzia e la giovent\uf9 (asili e giardini d\u2019infanzia, scuole abbecedarie e professionali per i fanciulli del popolo, orfanotrofi, conservatori femminili, educandati e collegi ecc.), promotori delle riforme scolastiche e del rinnovamento dei metodi d\u2019insegnamento e delle pratiche didattiche (non solo pedagogisti, ma anche esperti delle didattiche disciplinari, con un\u2019attenzione particolare al mondo scientifico e matematico), teorici della pedagogia emendativa e responsabili di istituti e scuole speciali per l\u2019educazione e istruzione dei disabili. E ancora: direttori e redattori dei periodici scolastici e magistrali, autori di libri di testo e inventori di sussidi didattici, scrittori e illustratori di libri per l\u2019infanzia e la giovent\uf9 e delle riviste destinate al mondo infantile e giovanile, teorici e promotori dell\u2019educazione fisica e sportiva, medici coinvolti nei progetti di miglioramento delle condizioni igieniche e di vita dei ceti popolari e impegnati in attivit\ue0 educative e rieducative, animatori dell\u2019associazionismo giovanile. Il Dizionario consente, attraverso le biografie presentate nell\u2019opera, di lumeggiare il fondamentale ruolo esercitato dall\u2019educazione scolastica e non nell\u2019opera di alfabetizzazione ed elevazione culturale e civile degli italiani e, parimenti, nel processo di costruzione dell\u2019identit\ue0 nazionale e di promozione di un nuovo ideale di cittadinanza in seno alle popolazioni