1,167 research outputs found

    Incomplete devil's staircase in the magnetization curve of SrCu2(BO3)2

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    We report on NMR and torque measurements on the frustrated quasi-two-dimensional spin-dimer system SrCu2(BO3)2 in magnetic fields up to 34 T that reveal a sequence of magnetization plateaus at 1/8, 2/15, 1/6, and 1/4 of the saturation and two incommensurate phases below and above the 1/6 plateau. The magnetic structures determined by NMR involve a stripe order of triplets in all plateaus, suggesting that the incommensurate phases originate from proliferation of domain walls. We propose that the magnetization process of SrCu2(BO3)2 is best described as an incomplete devil's staircase.Comment: 21 pages, 9 figures (main: 12 pages, 4 figures/supplemental material: 9 pages, 5 figures

    A horn-coupled millimeter-wave on-chip spectrometer based on Lumped Element Kinetic Inductance Detectors

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    Context. Millimetre-wave astronomy is an important tool for both general astrophysics studies and cosmology. A large number of unidentified sources are being detected by the large field-of-view continuum instruments operating on large telescopes. Aims. New smart focal planes are needed to bridge the gap between large bandwidth continuum instruments operating on single dish telescopes and the high spectral and angular resolution interferometers (e.g. ALMA in Chile, NOEMA in France). The aim is to perform low-medium spectral resolution observations and select a lower number of potentially interesting sources, i.e. high-redshift galaxies, for further follow-up. Methods. We have designed, fabricated and tested an innovative on-chip spectrometer sensitive in the 85-110~GHz range. It contains sixteen channels selecting a frequency band of about 0.2 GHz each. A conical horn antenna coupled to a slot in the ground plane collects the radiation and guides it to a mm-wave microstrip transmission line placed on the other side of the mono-crystalline substrate. The mm-wave line is coupled to a filter-bank. Each filter is capacitively coupled to a Lumped Element Kinetic Inductance Detector (LEKID). The microstrip configuration allows to benefit from the high quality, i.e. low losses, mono-crystalline substrate, and at the same time prevents direct, i.e. un-filtered, LEKID illumination. Results. The prototype spectrometer exhibit a spectral resolution R = lambda / Delta_lambda = 300. The optical noise equivalent power is in the low 1E-16W/sqrt(Hz) range for an incoming power of about 0.2pW per channel. The device is polarisation-sensitive, with a cross-polarisation lower than 1% for the best channels.Comment: Submitted to Astronomy & Astrophysic

    Clinical management methods for out-patients with alcohol dependence

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    BACKGROUND: In France outpatient centres for the care of alcoholics are healthcare establishments providing medical, psychological and social support. Although they meet the practical needs of these patients, their degree of use in each of these domains and the respective mobilisation of different skills by the care team are not well understood. Our aim was therefore to determine in detail the management involved as a function of the severity of alcohol dependence. For this purpose, all the procedures involved were compiled in a thesaurus describing its type (psychological, medical, social, reception), its scheduled or unscheduled nature, its method (face-to-face, telephone, letter) and its duration. The severity of dependence was evaluated using the Addiction Severity Index (ASI). RESULTS: 45 patients were included and followed-up during 291 ± 114 days. The mean initial ASI scores (± SD) were: medical (M) = 0.39 ± 0.3, working-income (ER) = 0.5 ± 0.3, alcohol (A) = 0.51 ± 0.2, illicit drugs (D) = 0.07 ± 0.08, legal (L) = 0.06 ± 0.13, familial and social environment (FS) = 0.34 ± 0.26, psychological (P) = 0.39 ± 0.22. The total number of procedures was 1341 (29.8 per patient) corresponding to 754.4 hours (16.7 per patient). The intensity of management peaked during the first month of treatment, and then declined rapidly; the maximum incidence of abstinence was observed during the 3rd month of management. Interviews with patients, group therapy and staff meetings represented 68.7%, 9.9% and 13.9% of all procedures, respectively. In patients with severe dependence, as compared to moderate, management was twice as intense in the psychological and social domains, but not in the medical domain. The ASI questionnaire was completed a second time by 24 patients, after an average of 3.2 months. The improvement was significant in the M, A, D and P domains only. CONCLUSION: This study provided an overview of the methods employed in managing a sample of patients consulting an alcoholism centre in line with standards for medical, psychological and social establishments. The predominance of the social and psychological domains over the medical domain was clearly established. Relapses were common after the third month of treatment, but a remobilisation of teams made it possible to contain them. These results provide a framework for discussions on the organisation of healthcare systems and highly suggest that staff need to maintain a constant level of care throughout the treatment process

    Employees' Organizational Identification and Affective Organizational Commitment: An integrative approach

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    Although several studies have empirically supported the distinction between organizational identification (OI) and affective commitment (AC), there is still disagreement regarding how they are related. Precisely, little attention has been given to the direction of causality between these two constructs and as to why they have common antecedents and outcomes. This research was designed to fill these gaps. Using a cross-lagged panel design with two measurement times, Study 1 examined the directionality of the relationship between OI and AC, and showed that OI is positively related to temporal change in AC, confirming the antecedence of OI on AC. Using a cross-sectional design, Study 2 investigated the mediating role of OI in the relationship between three work experiences (i.e., perceived organizational support, leader-member exchange, and job autonomy) and AC, and found that OI partially mediates the influence of work experiences on AC. Finally, Study 3 examined longitudinally how OI and AC combine in the prediction of actual turnover, and showed that AC totally mediates the relationship between OI and turnover. Overall, these findings suggest that favorable work experiences operate via OI to increase employees' AC that, in turn, decreases employee turnover

    THz Magneto-electric atomic rotations in the chiral compound Ba3_3NbFe3_3Si2_2O14_{14}

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    We have determined the terahertz spectrum of the chiral langasite Ba3_3NbFe3_3Si2_2O14_{14} by means of synchrotron-radiation measurements. Two excitations are revealed that are shown to have a different nature. The first one, purely magnetic, is observed at low temperature in the magnetically ordered phase and is assigned to a magnon. The second one persits far into the paramagnetic phase and exhibits both an electric and a magnetic activity at slightly different energies. This magnetoelectric excitation is interpreted in terms of atomic rotations and requires a helical electric polarization

    Incidence of adverse events in antipsychotic-naïve children and adolescents treated with antipsychotic drugs: a French multicentre naturalistic study protocol (ETAPE)

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    ETAPE Study groupInternational audienceIntroduction: In France, over recent years, the prescription rate of antipsychotic (AP) remained stable in children and adolescents. Prescription of second-generation antipsychotics increased, whereas prescription of first-generation antipsychotics decreased. Off-label prescriptions are very frequent in this population. Adverse events (AEs) in youth treated with AP are common and may be severe. AEs have hitherto been poorly monitored in naturalistic studies independent from industry.Method and analysis: We describe a French prospective multicentre study in an AP-naïve paediatric population named Etude de la Tolérance des AntiPsychotique chez l'Enfant (ETAPE). The study started in April 2013. So far, 200 patients have been included. The inclusion criteria are: male or female inpatients aged from 6 to 18 years, treated with an AP drug for less than 28 days, never been treated or having received AP for less than 3 months, discontinued at least 6 months prior to inclusion. These assessments of AE are performed at inclusion, as well as at 3, 6, 9 and 12 months after the introduction of the AP. The monitoring period will end in May 2016.Ethics and dissemination: The study protocol was approved by the Ethics Committee 'Sud Méditerrané V' (number 12.082) and by the French National Agency for Medicines and Health Products Safety (number 2012-004546-15). All patients and their parents signed informed consent on enrolment in the study. We will submit the results of the study to relevant journals and offer national and international presentations. This study will enable better characterisation of the prescription of AP drugs. The results will further help to develop quality standards and recommendations for monitoring AE during the prescription of AP

    Automatic State Reaching for Debugging Reactive Programs

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    In M. Ronsse, K. De Bosschere (eds), proceedings of the Fifth International Workshop on Automated Debugging (AADEBUG 2003), September 2003, Ghent. cs.SE/0309027AADEBUG 2003 Ghent - September 8 - 10th, 2003Reactive systems are made of programs that permanently interact with their environment. Debuggers generally provide support for data and state inspection, given a sequence of inputs. But, because the reactive programs and their environments are interdependent, a very useful feature is to be able to go the other way around; namely, given a state, obtain a sequence of inputs that leads to that state. This problem is equivalent to the general verification of safety properties, which is notoriously undecidable in presence of numeric variables. However, a lot of progress has been done in recent years through the development of model checking and abstract-interpretation-based techniques.In this article, we take advantage of those recent advances to implement a fully automatic state reaching capability inside a debugger of reactive programs. To achieve that, we connect a debugger, a verification tool, and a testing tool. One of the key contributions of our proposal is the proper handling of numeric variables

    Reconnaissance au travail (la)

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    La « reconnaissance » est devenue un nouvel enjeu de société. Le désir d’être reconnu envahit le monde du travail et imprègne les relations et les discours des individus. Reconnaissance de compétences, reconnaissance de la personne à travers son positionnement dans l’organisation, reconnaissance vis à vis de la hiérarchie et du groupe. Que revendiquet-on dans le monde du travail, quand on demande « une plus grande reconnaissance » ? quelles formes celle-ci peut-elle prendre, en particulier dans les démarches d’évaluation ou de validation de l’expérience ? Comment les entreprises abordent-elles ces attentes collectives et individuelles de reconnaissance
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