1,200 research outputs found
Prevalence estimates of neurodevelopmental disorders in Japan: A community sample questionnaire study
Abstract Aim The prevalence estimates of neurodevelopmental disorders have been calculated by questionnaire surveys scored by a single rater, which introduces inherent rater biases. The present study aimed to estimate the prevalence and comorbidity rates of four neurodevelopmental disorders based both on parent and teacher rating scales. Methods We performed a community sample survey recruiting 3852 children aged 6?9?years. Both parents and teachers evaluated clinical conditions in children using questionnaire-style scales. These scales with the cut-off values were used to estimate the prevalence and comorbidity rates of attention deficit / hyperactive disorder, autism spectrum disorder, specific learning disorder (or developmental dyslexia), and developmental coordination disorder. Results The prevalence estimates were separately confirmed according to the raters. Some estimates were higher than those in the previous studies conducted in other countries. We also found a large disagreement between the parent and teacher rating scores. Moreover, the degree of agreement between two raters varied depending on the severity of clinical condition in the child. Conclusion These estimates are the first findings based on evaluating children by two raters. The prevalence and comorbidity estimates are informative to the researchers and clinicians of pediatric neurology. The disagreement between two raters raises questions about previous estimates of neurodevelopmental disorders. This article is protected by copyright. All rights reserved.Peer reviewe
Computable analysis of linear rearrangement optimization
Optimization problems over rearrangement classes arise in various areas such as mathematics, fluid mechanics, biology, and finance. When the generator of the rearrangement class is two-valued, they reduce to shape optimization and free boundary problems which can exhibit intriguing symmetry breaking phenomena. A robust framework is required for computable analysis of these problems. In this paper, as a first step towards such a robust framework, we provide oracle Turing machines that compute the distribution function, decreasing rearrangement, and linear rearrangement optimizers, with respect to functions that are continuous and have no significant flat zones. This assumption on the reference function is necessary, as otherwise, the aforementioned operations may not be computable. We prove that the results can be computed to within any degree of accuracy, conforming to the framework of Type-II Theory of Effectivity
Novel High-Frequency Electric Field Sweeping Concept for High-Power Gyrotron Collectors
Future fusion power plants will require for plasma heating and noninductive current drive high-power gyrotrons, each of which generates 2 MW of continuous-wave microwave power, while another 2 MW in the spent electron beam is dissipated as heat on the collector wall. In today’s 1-MW continuous-wave gyrotrons, collector coils superimpose an ac (10–50 Hz) magnetic field to sweep the hot spots of spent electrons over a large area. However, to double today’s power, it will also be critical to reduce the hot spot dwell time preventing significant increase of material fatigue. This can be achieved by increasing the sweeping frequency. However, a higher frequency magnetic field would hardly penetrate the metallic collector vessel due to eddy currents. Instead of magnetic field, sweeping with electric fields is proposed for the first time. The presented mechanism is capable to apply several orders higher sweeping frequency to reduce the periodic variation of temperature, and thus, the device lifetime can be extended
Toward the First Continuous Wave Compatible Multistage Depressed Collector Design for High Power Gyrotrons
The multistage depressed collector (MDC) is essential to significantly increase the overall efficiency of the gyrotron. To date, a short pulse (SP) MDC prototype system has been manufactured and is currently under test. The long-term goal that makes the most sense is to use MDCs on 2-MW fusion gyrotrons in continuous wave (CW) operation. To achieve this, a CW MDC system based on the same physical principle as the SP system is designed and analyzed for the first time. The highlights of this design are the sweeping systems to keep the thermal loading within an acceptable limit when the MDC is operated in CW. In the present analysis, the expected performance and size of the new CW MDC design are compared with that of the SP MDC prototype and with the corresponding single-stage depressed collectors (SDCs) as a reference. In addition, the effects of thermal expansion in CW operation are analyzed and discussed
Metastability in the dilute Ising model
Consider Glauber dynamics for the Ising model on the hypercubic lattice with
a positive magnetic field. Starting from the minus configuration, the system
initially settles into a metastable state with negative magnetization. Slowly
the system relaxes to a stable state with positive magnetization. Schonmann and
Shlosman showed that in the two dimensional case the relaxation time is a
simple function of the energy required to create a critical Wulff droplet.
The dilute Ising model is obtained from the regular Ising model by deleting a
fraction of the edges of the underlying graph. In this paper we show that even
an arbitrarily small dilution can dramatically reduce the relaxation time. This
is because of a catalyst effect---rare regions of high dilution speed up the
transition from minus phase to plus phase.Comment: 49 page
Mechanical Design of the Short Pulse E×B Drift Two-Stage Depressed Collector Prototype for High Power Gyrotron
Multistage depressed collector (MDC) technology is capable of significantly increased overall tube efficiencies of vacuum electronic devices compared to conventional single stage depressed collectors (SDC). The spent electron beam sorting as used for TWT and klystron collectors is not effective in the high stray magnetic field of gyrotrons. For that reason, many new design approaches based on E×B drift concept have been theoretically investigated during the last years at KIT. The mechanical design for the first MDC for a high power gyrotron is finalized and the production started end of 2020. In this work, the fundamentals of the mechanical design and the cooling principle of the electrodes are presented
Mechanical Design of the Short Pulse E×B Drift Two-Stage Depressed Collector Prototype for High Power Gyrotron
Multistage depressed collector (MDC) technology is capable of significantly increased overall tube efficiencies of vacuum electronic devices compared to conventional single stage depressed collectors (SDC). The spent electron beam sorting as used for TWT and klystron collectors is not effective in the high stray magnetic field of gyrotrons. For that reason, many new design approaches based on E×B drift concept have been theoretically investigated during the last years at KIT. The mechanical design for the first MDC for a high power gyrotron is finalized and the production started end of 2020. In this work, the fundamentals of the mechanical design and the cooling principle of the electrodes are presented
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Unraveling the Light-Activated Reaction Mechanism in a Catalytically Competent Key Intermediate of a Multifunctional Molecular Catalyst for Artificial Photosynthesis
Understanding photodriven multielectron reaction pathways requires the identification and spectroscopic characterization of intermediates and their excited-state dynamics, which is very challenging due to their short lifetimes. To the best of our knowledge, this manuscript reports for the first time on in situ spectroelectrochemistry as an alternative approach to study the excited-state properties of reactive intermediates of photocatalytic cycles. UV/Vis, resonance-Raman, and transient-absorption spectroscopy have been employed to characterize the catalytically competent intermediate [(tbbpy)2RuII(tpphz)RhICp*] of [(tbbpy)2Ru(tpphz)Rh(Cp*)Cl]Cl(PF6)2 (Ru(tpphz)RhCp*), a photocatalyst for the hydrogenation of nicotinamide (NAD-analogue) and proton reduction, generated by electrochemical and chemical reduction. Electronic transitions shifting electron density from the activated catalytic center to the bridging tpphz ligand significantly reduce the catalytic activity upon visible-light irradiation. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA
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