1,013 research outputs found

    What\u27s new in spine surgery

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    Acceleration Of Protons To Above 6 MeV Using H2O >Snow> Nanowire Targets

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    A scheme is presented for using H2O >snow> nanowire targets for the generation of fast protons. This novel method may relax the requirements for very high laser intensities, thus reducing the size and cost of laser based ion acceleration system.Physic

    INFLUENCE OF TEACHER FACTORS ON ACADEMIC ACHIEVEMENT OF LEARNERS WITH ATTENTION-DEFICIT HYPERACTIVITY DISORDER (ADHD) IN INTERNATIONAL PRIMARY SCHOOLS OF MOMBASA (KENYA) AND KAMPALA (UGANDA): A COMPARATIVE STUDY

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    The purpose of this study was to investigate the influence of teacher factors (gender, qualification, and teaching experience) on academic achievement of learners with ADHD in inclusive learning environments in international primary schools of Mombasa (Kenya) and Kampala (Uganda). This was a comparative study that included 377 Learners (9-11 years) and their class teachers. The study adapted Attention Deficit Hyperactivity Disorder Scale Questionnaire (ADHD-SQ) which assessed the three ADHD subtypes, a self-formulated questionnaire that required class teachers to provide their demographic characteristic, and End of Term Assessment Results (ETAR) of learners in core subjects of math, science and English for their academic achievement. The results revealed that female class teachers in Kampala significantly influenced overall academic achievement (U = 19.50, p = .018) while male class teachers in Mombasa significantly influenced math achievement (U = 241.00, p = .036) of learners with ADHD condition. Teacher’s qualifications did not significantly influence academic achievement of learners with ADHD in Mombasa (rs = -.058, p = .675) and Kampala (rs = .334, p= .139). Teaching experience significantly influenced science achievement of learners with ADHD in Kampala (rs = -.486, p = .025). The study recommended exploration of these teacher factors in public primary schools across the two cities

    Results at 24 months from the prospective, randomized, multicenter Investigational Device Exemption trial of ProDisc-C versus anterior cervical discectomy and fusion with 4-year follow-up and continued access patients.

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    BackgroundCervical total disk replacement (TDR) is intended to address pain and preserve motion between vertebral bodies in patients with symptomatic cervical disk disease. Two-year follow-up for the ProDisc-C (Synthes USA Products, LLC, West Chester, Pennsylvania) TDR clinical trial showed non-inferiority versus anterior cervical discectomy and fusion (ACDF), showing superiority in many clinical outcomes. We present the 4-year interim follow-up results.MethodsPatients were randomized (1:1) to ProDisc-C (PDC-R) or ACDF. Patients were assessed preoperatively, and postoperatively at 6 weeks and 3, 6, 12, 18, 24, 36, and 48 months. After the randomized portion, continued access (CA) patients also underwent ProDisc-C implantation, with follow-up visits up to 24 months. Evaluations included Neck Disability Index (NDI), Visual Analog Scale (VAS) for pain/satisfaction, and radiographic and physical/neurologic examinations.ResultsRandomized patients (103 PDC-R and 106 ACDF) and 136 CA patients were treated at 13 sites. VAS pain and NDI score improvements from baseline were significant for all patients (P < .0001) but did not differ among groups. VAS satisfaction was higher at all time points for PDC-R versus ACDF patients (P = .0499 at 48 months). The percentage of patients who responded yes to surgery again was 85.6% at 24 months and 88.9% at 48 months in the PDC-R group, 80.9% at 24 months and 81.0% at 48 months in the ACDF group, and 86.3% at 24 months in the CA group. Five PDC-R patients (48 months) and no CA patients (24 months) had index-level bridging bone. By 48 months, approximately 4-fold more ACDF patients required secondary surgery (3 of 103 PDC-R patients [2.9%] vs 12 of 106 ACDF patients [11.3%], P = .0292). Of these, 6 ACDF patients (5.6%) required procedures at adjacent levels. Three CA patients required secondary procedures (24 months).ConclusionsOur 4-year data support that ProDisc-C TDR and ACDF are viable surgical options for symptomatic cervical disk disease. Although ACDF patients may be at higher risk for additional surgical intervention, patients in both groups show good clinical results at longer-term follow-up

    Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB

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    The plasma-based acceleration is an encouraging technique to overcome the limits of the accelerating gradient in the conventional RF acceleration. A plasma accelerator is able to provide accelerating fields up to hundreds of GeV/mGeV/m, paving the way to accelerate particles to several MeV over a short distance (below the millimetre range). Here the characteristics of preliminary electron beams obtained with the self-injection mechanism produced with the FLAME high-power laser at the SPARC_LAB test facility are shown. In detail, with an energy laser on focus of 1.5 J1.5\ J and a pulse temporal length (FWHM) of 40 fs40\ fs, we obtained an electron plasma density due to laser ionization of about 6×1018 cm−36 \times 10^{18}\ cm^{-3}, electron energy up to 350 MeV350\ MeV and beam charge in the range (50−100) pC(50 - 100)\ pC.Comment: 6 pages, 11 figures, conference EAAC201

    Need for Practice-Based Research in School Administration

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    Purpose: This article’s first objective is to establish the need for elevating the quantity and quality of practice-based research in school administration. The requirement is addressed in relation to (a) persisting social demands for school reform, (b) heightened demands for evidence-based practice in all professions, and (c) persistent criticisms indicating that field’s knowledge base and practice protocols are fragmented and weak. The second purpose is to propose that the need should be addressed at the level of individual preparation programs; specifically, faculty should assume responsibility for identifying and eradicating barriers to practice-based research. Proposed Conceptual Argument: In the context of an information-based society, practitioners in all professions are expected to access and analyze empirical data when addressing problems and making decisions. In school administration, the failure to respond to this anticipation presents both a social challenge (improving school effectiveness) and a professional challenge (legitimizing the need for practitioners to be licensed), and both are magnified by philosophical and epistemological dissonance among faculty. Implications: Reliance on external accountability in the absence of internal accountability will neither foster school improvement nor build social authority in school administration. Specifically, persistent indifference toward practice-based research and evidence-based practice will fuel doubts about the efficacy of professional administrators and the need to license them

    5.5-7.5 MeV Proton generation by a moderate intensity ultra-short laser interaction with H2O nano-wire targets

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    We report on the first generation of 5.5-7.5 MeV protons by a moderate intensity short-pulse laser (4.5 \times 1017 W/cm^2, 50 fsec) interacting with H2O nano-wires (snow) deposited on a Sapphire substrate. In this setup, the laser intensity is locally enhanced by the tip of the snow nano-wire, leading to high spatial gradients. Accordingly, the plasma near the tip is subject to enhanced ponderomotive potential, and confined charge separation is obtained. Electrostatic fields of extremely high intensities are produced over the short scale length, and protons are accelerated to MeV-level energies.Comment: submitted to PRL, under press embargo. 6 figure

    Frontiers of beam diagnostics in plasma accelerators: measuring the ultra-fast and ultra-cold

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    Advanced diagnostics are essential tools in the development of plasma-based accelerators. The accurate measurement of the quality of beams at the exit of the plasma channel is crucial to optimize the parameters of the plasma accelerator. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement, which is particularly complex due to large energy spread and divergence of the emerging beams, and on femtosecond bunch length measurements
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