1,571 research outputs found

    Quasi-Relativistic Center-of-Mass Variables in Applications

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    Collective center-of-mass variables are introduced in the Lagrangian formalism of the relativistic classical mechanics of directly interacting particles. It is shown that the transition to the Hamiltonian formalism leads to the Bakamjian-Thomas model. The quantum-mechanical system consisting of two spinless particles is investigated. Quasi-relativistic corrections to the discrete energy spectrum are calculated for some Coulomb-like interactions having field theoretical analogues.Comment: 12 pages, Latex2

    A Two-Form Formulation of the Vector-Tensor Multiplet in Central Charge Superspace

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    A two-form formulation for the N=2 vector-tensor multiplet is constructed using superfield methods in central charge superspace. The N=2 non-Abelian standard supergauge multiplet in central charge superspace is also discussed, as is with the associated Chern-Simons form. We give the constraints, solve the Bianchi identities and present the action for a theory of the vector-tensor multiplet coupled to the non-Abelian supergauge multiplet via the Chern-Simons form.Comment: 16 pages, LaTeX2e with AMS-LaTe

    Peak Power Scaling Of Nanosecond Pulses In Thulium Based Fiber Lasers

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    Thulium based fiber lasers represent a promising alternative for pulse energy scaling and high peak power generation with ytterbium based systems at 1µm. Advantages of thulium arise from the operation at longer wavelengths and a large gain bandwidth (1.8-2.1µm). Nonlinear effects, such as self phase modulation, stimulated Raman scattering and stimulated Brillouin scattering generally limit peak power scaling in fiber lasers. The longer wavelength of thulium fiber lasers and large mode field areas can significantly increase the nonlinear thresholds. Compared to 1µm systems, thulium fiber lasers enable single mode guidance for two times larger mode field diameter in step index fibers. Similar behavior is expected for index guiding thulium doped photonic crystal fibers. In this work a novel thulium doped rod type photonic crystal fiber design with large mode field diameter ( \u3e 50µm) was first characterized in CW-lasing configuration and then utilized as final amplifier in a two stage master oscillator power amplifier. The system generated MW-level peak power at 6.5ns pulse duration and 1kHz repetition rate. This world record performance exemplifies the potential of thulium fiber lasers to supersede ytterbium based systems for very high peak power generation in the future. As part of this work a computer model for the transient simulation of pulsed amplification in thulium based fiber lasers was developed. The simulations are in good agreement with the experimental results. The computer model can be used for efficient optimization of future thulium based fiber amplifier designs

    Effects of Small Group Instruction on Fact Fluency Progress

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    ABSTRACT This study will focus on the impact small group and individual instruction has on fact fluency. The specific group of facts being multiplication facts 0-12. This study will be based in a 6th grade math classroom in rural, central Minnesota. Students will be given a pre-test to assess their base knowledge of multiplication facts 0-12. Over the course of the study, student progress will be monitored through different interventions along with progress monitoring through the use of FastBridge. At the end of the study, students will also receive a post-test to help solidify the validity of the results for the study. During this study, students were divided into groups based upon which multiplication facts they needed more practice in. Students worked in small groups with the teacher-researcher with the main focus on skip counting and finding patterns. 1 day a week students participated in a whole group activity, 3 days a week they worked in selected small groups with the teacher researcher, and 1 day of the week students did progress monitoring. Through the process the researcher found that implementing small group and whole group instruction that focuses on number sense and fact fluency did improve students’ overall multiplication fact fluency

    Sozialraumerkundungen mit Menschen mit Lernschwierigkeiten : ein Projekt zur Untersuchung von Teilhabemöglichkeiten im Landkreis Weilheim-Schongau

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    Mit dem SGB IX hat die Behindertenhilfe eine Neuorientierung erfahren, welche nicht mehr Fürsorge und Verwahrung in den Mittelpunkt stellt, sondern Selbstbestimmung und Teilhabe von Menschen mit Behinderungen am Leben in der Gesellschaft. Zudem haben \u27Partizipation\u27 und \u27Inklusion\u27 in der aktuellen fachlichen Diskussion in der Behindertenhilfe einen hohen Stellenwert. In der Bundesrepublik Deutschland wurde im November 2008 die UN-Konvention über die Rechte von Menschen mit Behinderungen (UN-Behindertenrechtskonvention) ratifiziert. Sie greift Behinderung als Menschenrechtsthema auf und fordert die vollständige und wirksame Partizipation und Inklusion von Menschen mit Behinderungen in die Gesellschaft. Um dieser Herausforderung nach einem inklusiven Gemeinwesen nachzukommen, bedarf es einer sozialräumlichen Planung. Barrieren im Alltag entwickeln insbesondere für Menschen mit Lernschwierigkeiten die Gefahr, den Einstieg in die Gesellschaft dauerhaft zu verpassen oder später anhaltend ausgegrenzt zu werden. Die Untersuchung der Teilhabemöglichkeiten leistet einen Beitrag zum Verstehen, wie sich Sozialräume von Menschen mit Behinderungen gestalten. Dadurch wird eine kompetente und adäquate Entwicklung und Planung in der Behindertenhilfe ermöglicht, was eine Überwindung der bestehenden stationären Strukturen der Daseinsvorsorge mit sich bringt. Die Methode der Sozialraumerkundung mit Menschen mit Lernschwierigkeiten wird beschrieben und hinsichtlich Teilhabemöglichkeiten und Barrieren zur Teilhabe im Projektseminar "Leben im Landkreis Weilheim-Schongau" präzisiert. In der vorliegenden Arbeit stehen die gestalteten Sozialräume von Menschen mit und ohne Behinderungen im Mittelpunkt. Insbesondere interessiert die Frage, welche Barrieren im Alltag zur Teilhabe von Menschen mit Behinderungen auftreten und wie sich die Gestaltung der Sozialräume zwischen Menschen mit und ohne Behinderungen unterscheiden. Zu Sozialraumerkundungen mit Menschen mit Lernschwierigkeiten oder anderen Behinderungen gibt es bisher nur wenige Praxisbeispiele. Es handelt sich um einen neuen Ansatz in der Behindertenhilfe, welcher sich an die Ansätze und Methoden aus der Kinder- und Jugendhilfe anlehnt

    Overcoming Isolation as a Form of Leadership

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    Working in the technical services department of a small academic library is a bit of an isolation double-whammy: not only are you more removed from the patrons you serve than are your public-facing counterparts, you may also be a department of one and solely responsible for discharging a highly specialized set of duties. This has been the case for me since 2015 when I moved to Oregon after accepting the position of Acquisitions Specialist at Pacific University, a small, private, liberal arts college in Forest Grove. I am primarily responsible for tracking the library’s resource funds; overseeing the ordering, receiving, and invoicing process for all newly acquired materials; and aiming for the ever-moving target that is continuations budgeting. Prior to this position, I had mainly worked for larger institutions with more staff members who had the same or overlapping responsibilities. Over the past few years at Pacific, I have had to train myself in conquering the inherent isolation associated with my work. I’ve found that this has brought out leadership qualities I did not know I possessed, and I have identified a few ways in which I have been able to harness and hone these newfound skills
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