79 research outputs found

    What Works in School? Expert and Novice Teachers’ Beliefs about School Effectiveness

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    In 2009, John Hattie first published his extensive metasynthesis concerning determinants of student achievement. It provides an answer to the question: “What works in school?” The present study examines how this question is answered by pre- and in-service teachers, how their beliefs correspond to the current state of research and whether they differ according to the teachers' level of expertise. Thus, it takes on a novel approach as it draws on data from two sources in the field of education -- empirical research and teachers’ beliefs -- and examines their similarities and differences. The teachers’ beliefs were elicited by asking N = 729 participants to estimate the effect sizes of several determinants of student achievement. Those were compared to the empirical effect sizes found by Hattie (2009). Profile correlations showed that expert teachers’ beliefs are more congruent with current research findings than those of novice teachers. We further examined where expert and novice teachers’ beliefs differ substantially from each other by using confirmatory factor analysis (CFA) and comparing group means in latent variables. Our findings suggest that teachers’ beliefs about school effectiveness are related to professional experience: Expert teachers showed a stronger overall congruence with empirical evidence, scoring higher in achievement-related variables and lower in variables concerning surface- and infrastructural conditions of schooling as well as student-internal factors. Results are discussed with regard to teacher-education practices that emphasize research findings and challenge existing beliefs of (prospective) teachers

    Phantom-based evaluation of dose exposure of ultrafast combined kV-MV-CBCT towards clinical implementation for IGRT of lung cancer

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    Purpose: Combined ultrafast 90\ub0+90\ub0 kV-MV-CBCT within single breath-hold of 15s has high clinical potential for accelerating imaging for lung cancer patients treated with deep inspiration breath-hold (DIBH). For clinical feasibility of kV-MV-CBCT, dose exposure has to be small compared to prescribed dose. In this study, kV-MV dose output is evaluated and compared to clinically-established kV-CBCT. Methods: Accurate dose calibration was performed for kV and MV energy; beam quality was determined. For direct comparison of MV and kV dose output, relative biological effectiveness (RBE) was considered. CT dose index (CTDI) was determined and measurements in various representative locations of an inhomogeneous thorax phantom were performed to simulate the patient situation. Results: A measured dose of 20.5mGE (Gray-equivalent) in the target region was comparable to kV-CBCT (31.2mGy for widely-used, and 9.1mGy for latest available preset), whereas kVMV spared healthy tissue and reduced dose to 6.6mGE (30%) due to asymmetric dose distribution. The measured weighted CTDI of 12mGE for kV-MV lay in between both clinical presets. Conclusions: Dosimetric properties were in agreement with established imaging techniques, whereas exposure to healthy tissue was reduced. By reducing the imaging time to a single breathhold of 15s, ultrafast combined kV-MV CBCT shortens patient time at the treatment couch and thus improves patient comfort. It is therefore usable for imaging of hypofractionated lung DIBH patients

    Quality assurance process within the RAdiosurgery for VENtricular TAchycardia (RAVENTA) trial for the fusion of electroanatomical mapping and radiotherapy planning imaging data in cardiac radioablation

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    A novel quality assurance process for electroanatomical mapping (EAM)-to-radiotherapy planning imaging (RTPI) target transport was assessed within the multi-center multi-platform framework of the RAdiosurgery for VENtricular TAchycardia (RAVENTA) trial. A stand-alone software (CARDIO-RT) was developed to enable platform independent registration of EAM and RTPI of the left ventricle (LV), based on pre-generated radiotherapy contours (RTC). LV-RTC were automatically segmented into the American-Heart-Association 17-segment-model and a manual 3D-3D method based on EAM 3D-geometry data and a semi-automated 2D-3D method based on EAM screenshot projections were developed. The quality of substrate transfer was evaluated in five clinical cases and the structural analyses showed substantial differences between manual target transfer and target transport using CARDIO-RT

    Incidence of injury and pain in referees in German national handball leagues: a cohort study

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    Background: Handball referees play an important role during a handball match. Surprisingly, not much is known about their sports-related injuries and resulting pain, therefore the purpose of our study was to focus on injuries and sports-related pain in referees in German handball leagues. Methods: During the 2018/19 national German handball season, referees of the German Federation of Handball (DHB) were contacted and asked to complete an injury and pain questionnaire on the penultimate matchday of the first and the second round of the season. Results: Seventy referees participated in the study. One in three referees reported an injury during the last year and perceived some form of pain. Of those suffering from pain, 16.7% referees reported chronic pain disorders. During the season, 31.4% of referees incurred an injury and the majority of the 70 referees officiated despite pain (n = 43). Prospectively-enrolled data suggested an incidence of 11.6 (95% CI: 10.3 to 13.0) injuries per 1000 match hours, and 19.0 (95% CI: 16.8 to 21.3) sports-related pain events per 1000 match hours. The most common injuries were foot and knee injuries and a substantial number of the referees (n = 25) reported taking analgesics for the pain. Conclusion: German handball referees are at risk of sports-related injuries with subsequent pain. Considering the injury profile, the incidence of sports-related pain events, and the high physiological demands of refereeing, it appears that prevention programs should be developed and integrated into the routine of the referee

    Tyrosine Phosphorylation of the Tio Oncoprotein Is Essential for Transformation of Primary Human T Cells

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    Human T cells are transformed to antigen-independent permanent growth in vitro upon infection with herpesvirus saimiri subgroup C strains. The viral oncoproteins required for this process, StpC and Tip, could be replaced by Tio, the oncoprotein of herpesvirus ateles. Here we demonstrate that proliferation of lymphocytes transformed with Tio-recombinant herpesvirus saimiri required the activity of Src family kinases. Src kinases had previously been identified as interaction partners of Tio. This interaction was now shown to be independent of any of the four tyrosine residues of Tio but to be dependent on an SH3-binding motif. Mutations within this motif abrogated the transforming capabilities of Tio-recombinant herpesvirus saimiri. Furthermore, kinase interaction resulted in the phosphorylation of Tio on a single tyrosine residue at position 136. Mutation of this residue in the viral context revealed that this phosphorylation site, but none of the other tyrosine residues, was required for T-cell transformation. These data indicate that the interaction of Tio with a Src kinase is essential for both the initiation and the maintenance of T-cell transformation by recombinant herpesvirus saimiri. The requirement for the tyrosine phosphorylation site at position 136 suggests a role for Tio beyond simple deregulation of the kinase

    Herpesvirus Ateles Tio Can Replace Herpesvirus Saimiri StpC and Tip Oncoproteins in Growth Transformation of Monkey and Human T Cells

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    Herpesvirus saimiri group C strains are capable of transforming human and simian T-lymphocyte populations to permanent antigen-independent growth. Two viral oncoproteins, StpC and Tip, that are encoded by a single bicistronic mRNA, act in concert to mediate this phenotype. A closely related New World monkey herpesvirus, herpesvirus ateles, transcribes a single spliced mRNA at an equivalent genome locus. The encoded protein, Tio, has sequence homologies to both StpC and Tip. We inserted the tio sequence of herpesvirus ateles strain 73 into a recombinant herpesvirus saimiri C488 lacking its own stpC/tip oncogene. Simian as well as human T lymphocytes were growth transformed by the chimeric Tio-expressing viruses. Thus, a single herpesvirus protein appears to be responsible for the oncogenic effects of herpesvirus ateles

    Charakterisierung eines neuen Transmissionsdetektors für die patientenindividualisierte Online-Planverifikation und der Einfluss des Detektors auf die Strahlcharakteristik eines 6MV-Röntgentherapiestrahls

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    Purpose Online verification and 3D dose reconstruction on daily patient anatomy have the potential to improve treatment delivery, accuracy and safety. One possible implementation is to recalculate dose based on online fluence measurements with a transmission detector (TD) attached to the linac. This study provides a detailed analysis of the influence of a new TD on treatment beam characteristics. Methods The influence of the new TD on surface dose was evaluated by measurements with an Advanced Markus Chamber (Adv-MC) in the build-up region. Based on Monte Carlo simulations, correction factors were determined to scale down the over-response of the Adv-MC close to the surface. To analyze the effects beyond dmax percentage depth dose (PDD), lateral profiles and transmission measurements were performed. All measurements were carried out for various field sizes and different SSDs. Additionally, 5 IMRT-plans (head & neck, prostate, thorax) and 2 manually created test cases (3 × 3 cm2 fields with different dose levels, sweeping gap) were measured to investigate the influence of the TD on clinical treatment plans. To investigate the performance of the TD, dose linearity as well as dose rate dependency measurements were performed. Results With the TD inside the beam an increase in surface dose was observed depending on SSD and field size (maximum of +11%, SSD = 80 cm, field size = 30 × 30 cm2). Beyond dmax the influence of the TD on PDDs was below 1%. The measurements showed that the transmission factor depends slightly on the field size (0.893-0.921 for 5 × 5 cm2 to 30 × 30 cm2). However, the evaluation of clinical IMRT-plans measured with and without the TD showed good agreement after using a single transmission factor (γ(2%/2mm) > 97%, δ±3% >95%). Furthermore, the response of TD was found to be linear and dose rate independent (maximum difference <0.5% compared to reference measurements). Conclusions When placed in the path of the beam, the TD introduced a slight, clinically acceptable increase of the skin dose even for larger field sizes and smaller SSDs and the influence of the detector on the dose beyond dmax as well as on clinical IMRT-plans was negligible. Since there was no dose rate dependency and the response was linear, the device is therefore suitable for clinical use. Only its absorption has to be compensated during treatment planning, either by the use of a single transmission factor or by including the TD in the incident beam model
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