Full Hydrodynamic Simulation of GaAs MESFETs

A finite difference upwind discretization scheme in two dimensions is presented in detail for the transient simulation of the highly coupled non-linear partial differential equations of the full hydrodynamic model, providing thereby a practical engineering tool for improved charge carrier transport simulations at high electric fields and frequencies. The discretization scheme preserves the conservation and transportive properties of the equations. The hydrodynamic model is able to describe inertia effects which play an increasing role in different fields of micro- and optoelectronics, where simplified charge transport models like the drift-diffusion model and the energy balance model are no longer applicable. Results of extensive numerical simulations are shown for a two-dimensional MESFET device. A comparison of the hydrodynamic model to the commonly used energy balance model is given and the accuracy of the results is discussed.Comment: 18 pages, LATE

HHV-8 seroprevalence: a global view

BACKGROUND: Human herpes virus 8 (HHV-8) is the underlying infectious cause of Kaposi sarcoma (KS) and other proliferative diseases; that is, primary effusion lymphoma and multicentric Castleman disease. In regions with high HHV-8 seroprevalence in the general population, KS accounts for a major burden of disease. Outside these endemic regions, HHV-8 prevalence is high in men who have sex with men (MSM) and in migrants from endemic regions. We aim to conduct a systematic literature review and meta-analysis in order 1) to define the global distribution of HHV-8 seroprevalence (primary objective) and 2) to identify risk factors for HHV-8 infection, with a focus on HIV status (secondary objective).METHODS/DESIGN:We will include observational studies reporting data on seroprevalence of HHV-8 in children and/or adults from any region in the world. Case reports and case series as well as any studies with fewer than 50 participants will be excluded. We will search MEDLINE, EMBASE, and relevant conference proceedings without language restriction. Two reviewers will independently screen the identified studies and extract data on study characteristics and quality, study population, risk factors, and reported outcomes, using a standardized form. For the primary objective we will pool the data using a fully bayesian approach for meta-analysis, with random effects at the study level. For the secondary objective (association of HIV and HHV-8) we aim to pool odds ratios for the association of HIV and HHV-8 using a fully bayesian approach for meta-analysis, with random effects at the study level. Sub-group analyses and meta-regression analyses will be used to explore sources of heterogeneity, including factors such as geographical region, calendar years of recruitment, age, gender, ethnicity, socioeconomic status, different risk groups for sexually and parenterally transmitted infections (MSM, sex workers, hemophiliacs, intravenous drug users), comorbidities such as organ transplantation and malaria, test(s) used to measure HHV-8 infection, study design, and study quality.DISCUSSION:Using the proposed systematic review and meta-analysis, we aim to better define the global seroprevalence of HHV-8 and its associated risk factors. This will improve the current understanding of HHV-8 epidemiology, and could suggest measures to prevent HHV-8 infection and to reduce its associated cancer burden

Fremdsprache Englisch im ersten Lehrjahr. Wie wichtig ist Englisch für Berufsschüler im ersten Lehrjahr und wie entwickeln sich ihre Kompetenzen in dieser Fremdsprache während dieser Zeitspanne?

Angehende Lehrlinge haben unterschiedliche Voraussetzungen bezüglich ihrer Englischkenntnisse in der Oberstufe, je nachdem ob sie die Sekundar- oder Realstufe besucht haben und auch, wie ihnen das Fach und die Sprache persönlich liegen. Zudem beeinflussen unterschiedliche Weiterbildungsmöglichkeiten in der Berufsschule und dem Beruf, den sie wählen, ihre Fähigkeiten in der Fremdsprache Englisch. Diese Masterarbeit plant die subjektive Wichtigkeit der Fremdsprache Englisch sowie die Entwicklung der schriftlichen und mündlichen produktiven Fähigkeiten von Lehrlingen, während dem ersten Lehrjahr nach dem Abschluss der Oberstufe, zu untersuchen. Dabei liegt die Konzentration auf denjenigen Jugendlichen, die im Sommer 2014 die Oberstufe abgeschlossen und anschliessend eine Berufslehre begonnen haben. Als Erhebungsinstrumente dienen zum einen Tiefeninterviews, zum anderen Tests in Englisch in denen die beiden produktiven Fertigkeiten Schreiben und Sprechen untersucht werden sowie Selbstevaluation zu den schriftlichen und mündlichen Kompetenzen. Alle drei Erhebungsinstrumente werden, während dem Untersuchungseitraum, in einem zeitlichen Abstand von mehreren Monaten, drei Mal eingesetzt. Die Ergebnisse der Tests zeigen deutlich, dass alle vier Probanden, über den Erhebungszeitraum von etwa 9 Monaten, die untersuchten Sprachkompetenzen verbessern konnten. In den Selbstevaluationen durchlief nur ein Proband eine ähnliche Entwicklung, wie in den Tests. Alle anderen Probanden beurteilten sich, im fortschreitenden Verlauf der drei Untersuchungen, tendenziell schwächer. Die Probanden erkennen durchaus die Wichtigkeit in der Weiterentwicklung ihrer englischen Sprachkompetenzen, verfolgen damit aber grösstenteils Ziele, welche sie erst nach dem Abschluss der Berufslehre verwirklichen können. Eine Ursache davon liegt darin, dass alle Probanden am Arbeitsplatz während dem ersten Lehrjahr nur äusserst selten mit Englisch konfrontiert wurden. Dadurch beschränkte sich der Gebrauch von Englisch in dieser Zeit auf die Berufsschule und teilweise auf kurze Auslandaufenthalte in Form von Ferien. Da in den nächsten Jahren Jugendliche, welche die Oberstufe abschliessen werden, Frühenglisch in der Unter- und Mittelstufe besucht haben werden, kann diese Arbeit als Basis für weitere Untersuchungen der subjektiven Wichtigkeit von Englisch sowie der Entwicklung der Englischkompetenzen zukünftiger Lehrlinge des ersten Lehrjahres dienen

Prevalence of Attention Deficit Hyperactivity Disorder (ADHD) among Substance Use Disorder (SUD) Populations: Meta-Analysis

(1) Background: Attention deficit hyperactivity disorder (ADHD) is characterized by a persistent pattern of age-inappropriate levels of inattention and/or hyperactivity/impulsivity that results in functional impairment at work, education, or hobbies and affects family life, social contacts, and self-confidence. ADHD is a comorbid condition associated with a prognosis of severe substance use disorder (SUD) and the early onset of such. The aim of this meta-analysis was to obtain the best estimate of the prevalence of ADHD in SUD populations. (2) Methods: A literature research was conducted using PUBMED® and Web of Science®. The following search terms were used: [ADHD], [prevalence], and [substance use disorder]. RStudio® was used for meta-analysis methods. (3) Results: In total, 31 studies were included. We estimate the prevalence of ADHD among SUD patients at 21%

特集18 : 研究速報 : Towards Micro Magnetic Bearings

In order to avoid friction problems of micro devices, contact-free levitation methods are sought. With this project, a magnetic bearing for a disc-like rotor of 8mm diameter and 1mm thickness has been realized as a preliminary experiment to study scaling laws and possible approaches for very small magnetic bearings. The prototype has two actively controlled degrees of freedom for the suspension. The rotational angle of the rotor is also controllable, it has been designed as a simple stepper motor wlth an angular resolution of 1/48th of a full revolution. There seem to be no basic limitations to further down-scaling. The experiments described here were done at IIS as a masters thesis of F. Moesner and M. Rohner.特集 生産加工プロセスの先進技

Prevalence of attention deficit hyperactivity disorder (ADHD) among substance use disorder (SUD) populations: meta-analysis.

(1) Background: Attention deficit hyperactivity disorder (ADHD) is characterized by a persistent pattern of age-inappropriate levels of inattention and/or hyperactivity/impulsivity that results in functional impairment at work, education, or hobbies and affects family life, social contacts, and self-confidence. ADHD is a comorbid condition associated with a prognosis of severe substance use disorder (SUD) and the early onset of such. The aim of this meta-analysis was to obtain the best estimate of the prevalence of ADHD in SUD populations. (2) Methods: A literature research was conducted using PUBMED and Web of Science. The following search terms were used: [ADHD], [prevalence], and [substance use disorder]. RStudio was used for meta-analysis methods. (3) Results: In total, 31 studies were included. We estimate the prevalence of ADHD among SUD patients at 21%