99 research outputs found

    High power femtosecond source based on passively mode-locked 1055nm VECSEL and Yb-fibre power amplifier

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    We report 5 ns pulses at 160 W average power and 910 repetition rate from a passively mode-locked VECSEL source seeding an Yb-doped fibre power amplifier. The amplified pulses were compressed to 291 fs duration

    2s exciton-polariton revealed in an external magnetic field

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    We demonstrate the existence of the excited state of an exciton-polariton in a semiconductor microcavity. The strong coupling of the quantum well heavy-hole exciton in an excited 2s state to the cavity photon is observed in non-zero magnetic field due to surprisingly fast increase of Rabi energy of the 2s exciton-polariton in magnetic field. This effect is explained by a strong modification of the wave-function of the relative electron-hole motion for the 2s exciton state.Comment: 5 pages, 5 figure

    Engineering the spatial confinement of exciton-polaritons in semiconductors

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    We demonstrate the spatial confinement of electronic excitations in a solid state system, within novel artificial structures that can be designed having arbitrary dimensionality and shape. The excitations under study are exciton-polaritons in a planar semiconductor microcavity. They are confined within a micron-sized region through lateral trapping of their photon component. Striking signatures of confined states of lower and upper polaritons are found in angle-resolved light emission spectra, where a discrete energy spectrum and broad angular patterns are present. A theoretical model supports unambiguously our observations

    Preventing sexism and sexual harassment in medical schools by using Theater of the Oppressed as an interactive and reflexive tool.

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    Among the measures taken to combat sexism and sexual harassment, prevention courses for medical students are one possibility. We aimed to describe the process of implementing a training course on the prevention of sexism and sexual harassment for medical students in two Swiss medical schools by using the Theater of the Oppressed as an interactive and reflexive tool within the course. The purpose of this theater was to give the students the opportunity to express themselves and to collectively look for and discuss ways to combat and escape from oppressive situations. This collaborative, innovative, and interactive implementation showed that different forms of a training course can be implemented with similar objectives in an adaptable and transferable manner. The interactive and reflexive Theater of the Oppressed was an appropriate option to reach the objectives. Courses were based on identifying and acting on concrete problematic situations by focusing on individual, collective, and institutional resources. Students reported a high level of satisfaction

    Very High Frequency Oscillations (VHFO) as a Predictor of Movement Intentions

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    Gamma band (30-80 Hz) oscillations arising in neuronal ensembles are thought to be a crucial component of the neural code. Recent studies in animals suggest a similar functional role for very high frequency oscillations (VHFO) in the range 80-200Hz. Since some intracerebral studies in humans link VHFO to epileptogenesis, it remains unclear if VHFO appear in the healthy human brain and if so which is their role. This study uses EEG recordings from twelve healthy volunteers, engaged in a visuo-motor reaction time task, to show that VHFO are not necessarily pathological but rather code information about upcoming movements. Oscillations within the range (30-200Hz) occurring in the period between stimuli presentation and the fastest hand responses allow highly accurate (>96%) prediction of the laterality of the responding hand in single trials. Our results suggest that VHFO belong in functional terms to the gamma band that must be considerably enlarged to better understand the role of oscillatory activity in brain functioning. This study has therefore important implications for the recording and analysis of electrophysiological data in normal subjects and patients

    Violence in primary care: Prevalence and follow-up of victims

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    BACKGROUND: Primary care physicians underestimate the prevalence of domestic violence and community violence. Victims are therefore at risk of further episodes of violence, with psychological and physical consequences. We used an interview to assess the prevalence of domestic and community violence among Swiss natives and foreigners. In a follow-up study, we evaluated the consequences of the interview for the positive patients. METHODS: We evaluated the prevalence of violence by use of a questionnaire in an interview, in an academic general internal medicine clinic in Switzerland. In a follow-up, we evaluated the consequences of the interview for positive patients. The participants were 38 residents and 446 consecutive patients. Questionnaires were presented in the principal language spoken by our patients. They addressed sociodemographics, present and past violence, the security or lack of security felt by victims of violence, and the patients' own violence. Between 3 and 6 months after the first interview, we did a follow-up of all patients who had reported domestic violence in the last year. RESULTS: Of the 366 patients included in the study, 36 (9.8%) reported being victims of physical violence during the last year (physicians identified only 4 patients out of the 36), and 34/366 (9.3%) reported being victims of psychological violence. Domestic violence was responsible for 67.3% of the cases, and community violence for 21.8%. In 10.9% of the cases, both forms of violence were found. Of 29 patients who reported being victims of domestic violence, 22 were found in the follow-up. The frequency of violence had diminished (4/22) or the violence had ceased (17/22). CONCLUSION: The prevalence of violence is high; domestic violence is more frequent than community violence. There was no statistically significant difference between the Swiss and foreign patients' responses related to the rates of violence. Patients in a currently violent relationship stated that participating in the study helped them and that the violence decreased or ceased a few months later

    Conway–Coxeter Friezes and Mutation: A Survey

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    In this survey chapter, we explain the intricate links between Conway–Coxeter friezes and cluster combinatorics. More precisely, we provide a formula, relying solely on the shape of the frieze, describing how each individual entry in the frieze changes under cluster mutation. Moreover, we provide a combinatorial formula for the number of submodules of a string module, and with that a simple way to compute the frieze associated to a fixed cluster-tilting object in a cluster category of Dynkin type A in the sense of Caldero and Chapoton

    L’usage de la poésie haïku en psycho-oncologie

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    International audienceAbstract Aim: Our study aims to describe the discourseeffects of specific and structured protocol focused on severalhaiku poems about one patient, who have experienced cancer.Procedure: The protocol consists of 4 steps: a preliminaryexploratory interview, fifteen haiku proposed without a partof the poem (a creative writing filled in by the patient), a freeform haiku composed by the patient, and finally, a finalinterview.Clinical case: A man, D., aged 25, had tumor.Result: Using this protocol, we showed discourse variationson the illness before and after the experience of poetrywriting, by Tropes V8.4 software.Conclusion: Haiku poetry can be a useful tool in the contextof supportive interventions or as preparatory work for engagementin psychotherapeutic intervention. We believe thatthe formal structure of haikus can create conditions for aspecific poetic work composed of: poetic evocation, synthesis,and mapping of the most intimate experiences in oncologyenvironment.Résumé Objectif : Cette étude qualitative et exploratoirevise à décrire les effets d’un protocole poétique centré surles haïkus en psycho-oncologie sur l’approche de la maladiechez un patient atteint de cancer.Matériel et méthodes : Il s’agit d’un protocole d’écriturepoétique composé de quatre étapes : un entretien préliminaire,la proposition de 15 haïkus (sans le vers du milieu)tirés de grands auteurs japonais, la réalisation d’un poèmecomposé librement par deux patients atteints de cancer, unentretien final sur l’expérience de l’écriture poétique.Cas clinique : Un homme, M. D., âgé de 25 ans, qui est entraitement pour un cancer.Résultats : Nous montrons les variations discursives utiliséesavant et après l’expérience de l’écriture poétique, à travers lelogiciel Tropes V8.4.Conclusion : Le travail poétique avec le haïku peut être unoutil utile, dans un contexte de support clinique en institutionou comme préparation à un travail de psychothérapie. Nouspensons que la structure formelle des haïkus peut inviter à untravail poétique spécifique : évocation poétique, synthèse etschématisation des vécus plus intimes en milieu oncologique

    Zero dimensional exciton-polaritons

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    We present a novel semiconductor structure in which 0D polaritons coexist with 2D microcavity polaritons. Spatial trapping of the 2D microcavity polaritons results from the confinement of their photonic part in a potential well, consisting of an adjustable thickness variation of the spacer layer. This original technique allows to create polaritonic boxes of any size and shape. Strong coupling regime is evidenced by the typical energy level anticrossing, in real space and in momentum space, and supported by a theoretical model
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