11 research outputs found
Erklärvideos im Physikunterricht
Erklärvideos bilden ein neues informelles Bildungsangebot, welches im großen Maße von Schülerinnen und Schüler angenommen wird. Diese Videos haben bereits Einzug in den Physikunterricht erhalten und sie werden auch in verschiedenen Forschungsprojekten verwendet. Da sie auf die Vermittlung von Handlungen oder abstrakten Inhalten zielen, eignen sie sich z. B zur Unterstützung des Experimentierens oder zur Vertiefung von physikalischen Konzepten. Bisher gibt es keine systematische Untersuchung ihrer fachdidaktischen Qualität und der Wirkung unterrichtlicher Nutzungsformen. Die fachdidaktische Qualität betrifft einerseits die Angemessenheit der Erklärung und andererseits das gewählte Videodesign.Der Beitrag gibt einen Überblick über die diskutierten theoretischen Ansätze und empirischen Befunde zur Wirksamkeit von Erklärvideos. Die Diskussion mündet in Hypothesen und die Begründung eines Untersuchungsdesigns zu ihrer Überprüfung. Der Fokus liegt auf dem Einsatz von Erklärvideos beim Experimentieren. Variiert werden die Erklärqualität, die multimediale Qualität und die Nutzungsform; untersucht wird ihr Einfluss auf das deklarative Handlungs- und Konzeptwissen als abhängige Variablen
Zur Lernwirksamkeit von Erklärvideos in der Physik
Erklärvideos stellen für Lernende eine wichtiger werdende Lerngelegenheit dar. Die Forschungslage zum Thema Erklärvideos lässt zum Teil noch offen, welchen Einfluss die didaktische Qualität eines Erklärvideos und die Form der Einbettung in Lehr-Lernprozesse auf den Lernzuwachs haben. Weiterhin ist unklar, ob es Personengruppen gibt, die von Erklärvideos besonders profitieren können. Ziel der Arbeit ist es daher, einen theoriebasierten Kategorienkatalog zur Gestaltung möglichst lernwirksamer Erklärvideos zu entwickeln, zwei Erklärvideos unterschiedlicher didaktischer Qualität zu einem Thema aus der Elektrizitätslehre zu gestalten und anhand dieser beiden Videos die Lernwirksamkeit empirisch zu prüfen. Die Erhebung mit N = 146 Lehramtsstudierenden des Sachunterrichts zeigt über alle Treatmentgruppen große Lernzuwächse. Aus den Ergebnissen folgt, dass die Qualität und auch das Einbettungsformat in dieser Erhebung keinen direkten Einfluss auf den Lernzuwachs haben. Aus der Betrachtung der Nutzungsdaten der Erklärvideos folgt als eine mögliche Erklärung, dass die Studierenden auch im schlechteren Erklärvideo relevante Inhalte identifizieren können. Es konnte beobachtet werden, dass besonders im Vorwissen schwache Studierende überproportional von Erklärvideos profitieren. Der mögliche Lernzuwachs bei der Nutzung von Erklärvideos hängt somit von den individuellen Lernvoraussetzungen der Lernenden ab
Exploring the effects of physics explainer videos and written explanations on declarative knowledge and the illusion of understanding
Studies have shown the potential of science explainer videos. An alternative is a written explanation, as found in science textbooks. Prior research suggests that instructional explanations sometimes lead to the belief that a topic has been fully understood, even though that is, objectively, not the case. This “illusion of understanding” may be affected by the medium of the explanation. Animations tend to falsely imply an easy explanation, which might result in explainer videos supporting the illusion of understanding. Textbook entries may appear to be more reliable and formal, resulting in an overestimation of the learning gains from this medium. Also, prior studies comparing the achievement from both media come to ambiguous results. In the present experimental study (N = 150 learners), we compared the effects of an explainer video introducing the concept of force to a written explanation containing the script of the video and two images, as though it is a page from a textbook. Both groups achieved comparable degrees of declarative knowledge, however, the written explanation video group had a significantly higher belief of understanding (partial 2 = 0.043) that did not correspond with their actual learning progress. Consequences of this potential illusion of understanding may include lower cognitive activation and less motivation in science classrooms if learning environments exclude further learning tasks that allow for a more realistic picture of understanding. That might suggest that it is sometimes potentially harmful to leave physics learners to their own devices with instructional material
Outcome and prognostic factors following palliative craniospinal irradiation for leptomeningeal carcinomatosis
Leptomeningeal carcinomatosis (LC) is a severe complication of metastatic tumor spread to the central nervous system. Prognosis is dismal with a median overall survival (OS) of ~10-15 weeks. Treatment options include radiotherapy (RT) to involved sites, systemic chemo- or targeted therapy, intrathecal chemotherapy and best supportive care with dexamethasone. Craniospinal irradiation (CSI) is a more aggressive radiotherapeutic approach, for which very limited data exists. Here, we report on our 10-year experience with palliative CSI of selected patients with LC
Stereotactic body radiotherapy (SBRT) for medically inoperable lung metastases-A pooled analysis of the German working group "stereotactic radiotherapy"
OBJECTIVES The current literature on stereotactic body radiotherapy (SBRT) for oligometastatic disease is characterized by small patient cohorts with heterogeneous primary tumors, metastases location and dose regimes. Hence, this study established a multi-institutional database of 700 patients treated with SBRT for pulmonary metastases to identify prognostic factors influencing survival and local control. MATERIALS AND METHODS All German radiotherapy departments were contacted and invited to participate in this analysis. A total number of 700 patients with medically inoperable lung metastases treated with SBRT in 20 centers between 1997 and 2014 were included in a database. Primary and metastatic tumor characteristics, treatment characteristics and follow-up data including survival, local control, distant metastases, and toxicity were evaluated. Lung metastases were treated with median PTV-encompassing single doses of 12.5Gy (range 3.0-33.0Gy) in a median number of 3 fractions (range 1-13). RESULTS After a median follow-up time of 14.3 months, 2-year local control (LC) and overall survival (OS) were 81.2% and 54.4%, respectively. In multivariate analysis, OS was most significantly influenced by pretreatment performance status, maximum metastasis diameter, primary tumor histology, time interval between primary tumor diagnosis and SBRT treatment and number of metastases. For LC, independent prognostic factors were pretreatment performance status, biological effective dose (BED) at PTV isocenter (BEDISO) and single fraction (PTV-encompassing) dose in multivariate analysis. Radiation-induced pneumonitis grade 2 or higher was observed in 6.5% of patients. The only factor significantly influencing toxicity was BEDISO (p=0.006). CONCLUSION SBRT for medically inoperable patients with pulmonary metastases achieved excellent local control and promising overall survival. Important prognostic factors were identified for selecting patients who might benefit most from this therapy approach
Local tumor control probability modeling of primary and secondary lung tumors in stereotactic body radiotherapy
Influence of Institutional Experience and Technological Advances on Outcome of Stereotactic Body Radiation Therapy for Oligometastatic Lung Disease
Purpose: Many technological and methodical advances have made stereotactic body radiotherapy (SBRT) more accurate and more efficient during the last years. This study aims to investigate whether experience in SBRT and technological innovations also translated into improved local control (LC) and overall survival (OS). Methods and Materials: A database of 700 patients treated with SBRT for lung metastases in 20 German centers between 1997 and 2014 was used for analysis. It was the aim of this study to investigate the impact of fluorodeoxyglucose positron-emission tomography (FDG-PET) staging, biopsy confirmation, image guidance, immobilization, and dose calculation algorithm, as well as the influence of SBRT experience, on LC and OS. Results: Median follow-up time was 14.3 months (range, 0-131.9 months), with 2-year LC and OS of 81.2% (95% confidence interval [CI] 75.8%-85.7%) and 54.4% (95% CI 50.2%-59.0%), respectively. In multivariate analysis, all treatment technologies except FDG-PET staging did not significantly influence outcome. Patients who received pre-SBRT FDG-PET staging showed superior 1- and 2-year OS of 82.7% (95% CI 77.4%-88.6%) and 64.8% (95% CI 57.5%-73.3%), compared with patients without FDG-PET staging resulting in 1- and 2-year OS rates of 72.8% (95% CI 67.4%-78.8%) and 52.6% (95% CI 46.0%-60.4%), respectively (P=.012). Experience with SBRT was identified as the main prognostic factor for LC: institutions with higher SBRT experience (patients treated with SBRT within the last 2 years of the inclusion period) showed superior LC compared with less-experienced centers (P 64.001). Experience with SBRT within the last 2 years was independent from known prognostic factors for LC. Conclusion: Investigated technological and methodical advancements other than FDG-PET staging before SBRT did not significantly improve outcome in SBRT for pulmonary metastases. In contrast, LC was superior with increasing SBRT experience of the individual center
Bayesian cure rate modeling of local tumor control: evaluation in stereotactic body radiation therapy for pulmonary metastases
PURPOSE: Most radiobiological models for prediction of tumor control probability (TCP) do not account for the fact that many events could remain unobserved because of censoring. We therefore evaluated a set of TCP models that take into account this censoring.
METHODS AND MATERIALS: We applied 2 fundamental Bayesian cure rate models to a sample of 770 pulmonary metastasis treated with stereotactic body radiation therapy at German, Austrian, and Swiss institutions: (1) the model developed by Chen, Ibrahim and Sinha (the CIS99 model); and (2) a mixture model similar to the classic model of Berkson and Gage (the BG model). In the CIS99 model the number of clonogens surviving the radiation treatment follows a Poisson distribution, whereas in the BG model only 1 dominant recurrence-competent tissue mass may remain. The dose delivered to the isocenter, tumor size and location, sex, age, and pretreatment chemotherapy were used as covariates for regression.
RESULTS: Mean follow-up time was 15.5 months (range: 0.1-125). Tumor recurrence occurred in 11.6% of the metastases. Delivered dose, female sex, peripheral tumor location and having received no chemotherapy before RT were associated with higher TCP in all models. Parameter estimates of the CIS99 were consistent with the classical Cox proportional hazards model. The dose required to achieve 90% tumor control after 15.5 months was 146 (range: 114-188) Gy10 in the CIS99 and 133 (range: 101-164) Gy10 in the BG model; however, the BG model predicted lower tumor control at long (≳20 months) follow-up times and gave a suboptimal fit to the data compared to the CIS99 model.
CONCLUSIONS: Biologically motivated cure rate models allow adding the time component into TCP modeling without being restricted to the follow-up period which is the case for the Cox model. In practice, application of such models to the clinical setting could allow for adaption of treatment doses depending on whether local control should be achieved in the short or longer term