354 research outputs found

    Planar measurements of spray-induced wall cooling using phosphor thermometry

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    The wall cooling induced by spray impingement is investigated using phosphor thermometry. Thin coatings of zinc oxide (ZnO) phosphor were applied with a transparent chemical binder onto a steel surface. Instantaneous spatially resolved temperatures were determined using the spectral intensity ratio method directly after the injection of UV-grade hexane onto the surface using a commercial gasoline injector. The investigations showed that 2D temperature measurements with high spatial and shot-to-shot precision of, respectively, 0.5 and 0.6 K can be achieved, allowing the accurate resolution of the cooling induced by the spray. The presence of a liquid film over the phosphor coating during measurements showed no noticeable influence on the measured temperatures. However, in some cases a change in the intensity ratio at the spray impingement area, in the form of a permanent “stain”, could be observed after multiple injections. The formation of this stain was less likely with increasing annealing time of the coating as well as lower plate operating temperatures during the injection experiments. Finally, the experimental results indicate a noticeable influence of the thickness of the phosphor coating on the measured spray-induced wall cooling history. Hence, for quantitative analysis, a compromise between coating thickness and measurement accuracy needs to be considered for similar applications where the heat transfer rates are very high

    Thermographic laser Doppler velocimetry using the phase-shifted luminescence of BAM:Eu2+ phosphor particles for thermometry

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    Simultaneous point measurements of gas velocity and temperature were recently demonstrated using thermographic phosphors as tracer particles. There, continuous wave (CW) excitation was used and the spectral shift of the luminescence was detected with a two-colour intensity ratio method to determine the gas temperature. The conventional laser Doppler velocimetry (LDV) technique was employed for velocimetry. In this paper, an alternative approach to the gas temperature measurements is presented, which is instead based on the temperature-dependence of the luminescence lifetime. The phase-shift between the luminescence signal and time-modulated excitation light is evaluated for single BaMgAl10O17:Eu2+ phosphor particles as they cross the probe volume. Luminescence lifetimes evaluated in the time domain and frequency domain indicate that in these experiments, interferences from in-phase signals such as stray excitation laser light are negligible. The dependence of the phase-shift on flow temperature is characterised. In the temperature sensitive range above 700 K, precise gas temperature measurements can be obtained (8.6 K at 840 K) with this approach

    Psychiatric and psychological follow-up of undergraduate and postgraduate medical students: prevalence and associated factors. Results from the national BOURBON study. Running title: mental health and addictive behavior of medical students

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    International audienceBackgroundPhysicians are at risk of burnout, anxiety and depression. Prevention is needed from the beginning of the medical studies to detect early poor mental health outcomes.ObjectiveTo determine the prevalence and associated of psychiatric or psychological follow-up in a national sample of undergraduate and postgraduate medical students (UPMS).MethodsUPMS of the 35 French Medicine faculties were recruited through mailing lists and social networks between December 2016 and May 2017 and fulfilled Internet anonymised questionnaires.ResultsOverall, 10,985 UPMS were included in the present study (2165 (19.7%) postgraduate, 31.6% males, mean aged 21.8 years). Overall, 1345 (12.2%) were followed-up by a psychiatrist and/or a psychologist, 20.5% of them were regular anxiolytic consumers and 17.2% of them were regular antidepressant consumers. In multivariate analyses, being followed-up by a psychiatrist and/or psychologist was associated with older age (aOR = 1.2[1.2–1.2], p < 0.0001), female gender (aOR = 0.5[0.5–0.7], p < 0.0001), current alcohol use disorder (aOR = 1.3[1.3–1.5], p < 0.0001), higher anxiolytic (aOR = 3.1[2.5–3.7],p < 0.0001) and antidepressant (aOR = 11.7[7.6–18.0],p < 0.0001) consumption, and with lower self-reported general health, social functioning and mental health quality of life (all aORs = 0.9, all p < 0.05). The UPMS followed-up by psychiatrist and/or psychologist reported to have been more frequently exposed to sexual assault (5.1% vs. 0.9%, aOR = 2.5[1.3–4.7], p < 0.0001), domestic violence (3.3% vs. 0.8% aOR = 2.1[1.2–4.0], p = 0.01) and parents divorce (11% vs. 6.4%, aOR = 1.5[1.2–1.9], p = 0.001). Students followed-up by a psychiatrist and/or psychologist reported more frequently to seek alleviating anxiety (aOR 1.9[1.6–2.3], p < 0.0001), depression (aOR 1.7[1.3–2.1],p < 0.0001), coping with studies difficulties (aOR 1.5[1.2–1.8],p < 0.0001), experiencing more stress at hospital (aOR = 2.3[1.6–3.5],p < 0.001) and more burnout syndrome (aOR = 1.4[1.1–1.8], p = 0.03).ConclusionsAround 12% of UPMS are followed-up by a psychiatrist and/or a psychologist. These students reported higher antidepressant and anxiolytic consumption, psychic suffering and altered quality of life, associated with professional pressure and personal issues. Public health programs should be developed to help these students through their studies to prevent later mental /addictive issues and professional suffering. Improving UPMS mental health may also improve the later quality of care of their patients and global stress at hospital

    Improving the treatment and remission of major depression in homeless people with severe mental illness: the multicentric French Housing First (FHF) program. French Housing First Study Group Running title: Major depression in homeless people with severe mental disorders

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    International audienceObjectiveThe aim of this study was to investigate the factors associated with violent behavior in a large multicenter sample of Homeless Schizophrenia (SZ) and Bipolar Disorder (BD) (HSB) subjects.MethodsThis multicenter study was conducted in 4 French cities: Lille, Marseille, Paris and Toulouse. Violent behavior was defined by at least one episode of verbal or physical violence in the last 6 months.ResultsOverall, 675 HSB patients, mean aged 38 years and 82.5% men were included, 458 SZ (68.4%) and 212 BD (31.6%). During the 6 months before evaluation, 213 (34.3%) committed at least one physical or verbal violence. In multivariate analysis, violence has been associated with younger age (aOR = 0.96[0.94–0.99], p = .001), number of nights in the street (aOR = 1.01[1.01–1.01]), BD diagnosis (aOR = 1.63[1.01–2.65], p = .04), higher current illness severity (CGI score) (aOR = 1.32[1.07–1.64], p = .01), higher rates of current manic episode (aOR = 2.24[1.32–3.81], p = .002), current alcohol use disorder (aOR = 2.05 [1.33–3.15], p = .001), antisocial personality disorder (aOR = 2.51[1.55–4.07], p < .001) and with antidepressant consumption (aOR = 2.01[1.01–4.04], p = .04). No specific antipsychotic or mood stabilizer has been associated with decreased rates of violent behavior, however clozapine, lithium and carbamazepine remained poorly prescribed.ConclusionIn case of violent behavior in HSB subjects, clinicians should focus in priority on the treatment of mania, antidepressant iatrogenic effect and alcohol use disorder by pharmacological and non-pharmacological treatments. Clozapine, lithium and carbamazepine should be chosen as the treatments of reference in this population but may be hard to manage in some cases.The current clinical trial number is NCT01570712

    Offender rehabilitation : a normative framework for forensic psychologists

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    Community protection from offenders is addressed through punishment, deterrence, incapacitation, and/or rehabilitation. The current public policy debate about community protection refers to community rights as opposed to offender rights as if the two are mutually exclusive. However, in this article it will be argued that offender rehabilitation can enhance community protection if it addresses community rights and offender rights. The author proposes a normative framework to guide forensic psychologists in offender rehabilitation. The normative framework considers psychological theory&mdash;the risk-need model to address community rights and the good lives model to address offender rights. However, forensic psychologists operate within the context of the criminal justice system and so legal theory will also be considered. Therapeutic jurisprudence can balance community rights and offender rights within a human rights perspective. The proposed normative framework guides forensic psychologists in the assessment of risk, the treatment of need, and the management of readiness in balancing community rights and offender rights. Within a human rights perspective, forensic psychologists have a duty to provide offenders with the opportunity to make autonomous decisions about whether to accept or reject rehabilitation. <br /
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