490 research outputs found

    Further Comparison between ATNoSFERES and XCSM

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    International audienceIn this paper we present ATNoSFERES, a new framework based on an indirect encoding Genetic Algorithm which builds finite-state automata controllers able to deal with perceptual aliazing. In the context of our ongoing line of research, we compare it with XCSM, a memory-based extension of the most studied Learning Classifier System, XCS, through two benchmark experiments. We focus in particular on internal state generalization, and add special purpose features to ATNoSFERES to fulfill that comparison. We then discuss the role played by internal state generalization in the experiments studied

    Angle-integrated measurements of the 26Al (d, n)27Si reaction cross section: a probe of spectroscopic factors and astrophysical resonance strengths

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    Measurements of angle-integrated cross sections to discrete states in 27Si have been performed studying the 26Al (d, n) reaction in inverse kinematics by tagging states by their characteristic γ \gamma -decays using the GRETINA array. Transfer reaction theory has been applied to derive spectroscopic factors for strong single-particle states below the proton threshold, and astrophysical resonances in the 26Al (p,γ \gamma) 27Si reaction. Comparisons are made between predictions of the shell model and known characteristics of the resonances. Overall very good agreement is obtained, indicating this method can be used to make estimates of resonance strengths for key reactions currently largely unconstrained by experiment

    Les enseignants: à la recherche de leur profession

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    Les Enseignants: à la recherche de leur profession reprend les idées centrales présentées à la Conférence donnée, sur l'invitation de l'ATEE, au Séminaire de Barcelone, en 1993. Cet article est la reproduction du texte de support à la Conférence. Étant donné l'espace disponible, il n'a pas été possible de le travailler dans le sens d'une plus grande problématisation et élaboration théorique

    Grain Surface Models and Data for Astrochemistry

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    AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

    Ergonomics and sustainability: Towards and embrace of complexity and emergence

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    Technology offers a promising route to a sustainable future, and ergonomics can serve a vital role. The argument of this article is that the lasting success of sustainability initiatives in ergonomics hinges on an examination of ergonomics' own epistemology and ethics. The epistemology of ergonomics is fundamentally empiricist and positivist. This places practical constraints on its ability to address important issues such as sustainability, emergence and complexity. The implicit ethical position of ergonomics is one of neutrality, and its positivist epistemology generally puts value-laden questions outside the parameters of what it sees as scientific practice. We argue, by contrast, that a discipline that deals with both technology and human beings cannot avoid engaging with questions of complexity and emergence and seeking innovative ways of addressing these issues.No Full Tex

    Solar parameters for modeling interplanetary background

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    The goal of the Fully Online Datacenter of Ultraviolet Emissions (FONDUE) Working Team of the International Space Science Institute in Bern, Switzerland, was to establish a common calibration of various UV and EUV heliospheric observations, both spectroscopic and photometric. Realization of this goal required an up-to-date model of spatial distribution of neutral interstellar hydrogen in the heliosphere, and to that end, a credible model of the radiation pressure and ionization processes was needed. This chapter describes the solar factors shaping the distribution of neutral interstellar H in the heliosphere. Presented are the solar Lyman-alpha flux and the solar Lyman-alpha resonant radiation pressure force acting on neutral H atoms in the heliosphere, solar EUV radiation and the photoionization of heliospheric hydrogen, and their evolution in time and the still hypothetical variation with heliolatitude. Further, solar wind and its evolution with solar activity is presented in the context of the charge exchange ionization of heliospheric hydrogen, and in the context of dynamic pressure variations. Also the electron ionization and its variation with time, heliolatitude, and solar distance is presented. After a review of all of those topics, we present an interim model of solar wind and the other solar factors based on up-to-date in situ and remote sensing observations of solar wind. Results of this effort will further be utilised to improve on the model of solar wind evolution, which will be an invaluable asset in all heliospheric measurements, including, among others, the observations of Energetic Neutral Atoms by the Interstellar Boundary Explorer (IBEX).Comment: Chapter 2 in the planned "Cross-Calibration of Past and Present Far UV Spectra of Solar System Objects and the Heliosphere", ISSI Scientific Report No 12, ed. R.M. Bonnet, E. Quemerais, M. Snow, Springe

    Internet and Telephone Support for Discontinuing Long-Term Antidepressants: The REDUCE Cluster Randomized Trial

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    Importance: There is significant concern regarding increasing long-term antidepressant treatment for depression beyond an evidence-based duration. Objective: To determine whether adding internet and telephone support to a family practitioner review to consider discontinuing long-term antidepressant treatment is safe and more effective than a practitioner review alone. Design, Setting, and Participants: In this cluster randomized clinical trial, 131 UK family practices were randomized between December 1, 2018, and March 31, 2022, with remote computerized allocation and 12 months of follow-up. Participants and researchers were aware of allocation, but analysis was blind. Participants were adults who were receiving antidepressants for more than 1 year for a first episode of depression or more than 2 years for recurrent depression who were currently well enough to consider discontinuation and wished to do so and who were at low risk of relapse. Of 6725 patients mailed invitations, 330 (4.9%) were eligible and consented. Interventions: Internet and telephone self-management support, codesigned and coproduced with patients and practitioners. Main Outcomes and Measures: The primary (safety) outcome was depression at 6 months (prespecified complete-case analysis), testing for noninferiority of the intervention to under 2 points on the 9-item Patient Health Questionnaire (PHQ-9). Secondary outcomes (testing for superiority) were antidepressant discontinuation, anxiety, quality of life, antidepressant withdrawal symptoms, mental well-being, enablement, satisfaction, use of health care services, and adverse events. Analyses for the main outcomes were performed on a complete-case basis, and multiple imputation sensitivity analysis was performed on an intention-to-treat basis. Results: Of 330 participants recruited (325 eligible for inclusion; 178 in intervention practices and 147 in control practices; mean [SD] age at baseline, 54.0 [14.9] years; 223 women [68.6%]), 276 (83.6%) were followed up at 6 months, and 240 (72.7%) at 12 months. The intervention proved noninferior; mean (SD) PHQ-9 scores at 6 months were slightly lower in the intervention arm than in the control arm in the complete-case analysis (4.0 [4.3] vs 5.0 [4.7]; adjusted difference, -1.1; 95% CI, -2.1 to -0.1; P = .03) but not significantly different in an intention-to-treat multiple imputation sensitivity analysis (adjusted difference, -0.9 (95% CI, -1.9 to 0.1; P = .08). By 6 months, antidepressants had been discontinued by 66 of 145 intervention arm participants (45.5%) who provided discontinuation data and 54 of 129 control arm participants (41.9%) (adjusted odds ratio, 1.02; 95% CI, 0.52-1.99; P = .96). In the intervention arm, antidepressant withdrawal symptoms were less severe, and mental well-being was better compared with the control arm; differences were small but significant. There were no significant differences in the other outcomes; 28 of 179 intervention arm participants (15.6%) and 22 of 151 control arm participants (14.6%) experienced adverse events. Conclusions and Relevance: In this cluster randomized clinical trial of adding internet and telephone support to a practitioner review for possible antidepressant discontinuation, depression was slightly better with support, but the rate of discontinuation of antidepressants did not significantly increase. Improvements in antidepressant withdrawal symptoms and mental well-being were also small. There were no significant harms. Family practitioner review for possible discontinuation of antidepressants appeared safe and effective for more than 40% of patients willing and well enough to discontinue. Trial Registration: ISRCTN registry Identifiers: ISRCTN15036829 (internal pilot trial) and ISRCTN12417565 (main trial)
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