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Hintergrund: Die COVID-19(„coronavirus disease 2019“)-Pandemie hat die Ad-hoc-Digitalisierung an Hochschulen vorangetrieben. Zugleich stand die digitale Hochschullehre vor der Herausforderung der Ausgestaltung der Lehre im Zusammenhang mit den vorbestehenden Ressourcen, der digitalen und didaktischen Kompetenzen sowie der zur Verfügung stehenden technischen Infrastruktur.
Ziel der Arbeit/Fragestellung: Das Ziel der Umfrage war die Einschätzung der digitalen Lehre, die die Präsenzlehre infolge der COVID-19-Pandemie zum großen Teil bzw. gänzlich ersetzt hat, aus der Perspektive der Lehrenden in Public Health, Medizin und Pflege.
Material und Methode: Die Querschnitterhebung fand online von Juni bis August 2020 statt und die Daten wurden über www.soscisurvey.de erhoben. Die schriftliche Befragung wurde unter Mitgliedern der Deutschen Gesellschaft für Public Health (DGPH) und des Ausschusses Digitalisierung der Gesellschaft für medizinische Ausbildung (GMA) und der Sektionen Bildung und Beratung der Deutschen Gesellschaft für Pflegewissenschaft (DGP) sowie der Arbeitsgruppe Lehre der Deutschen Gesellschaft für Medizinische Soziologie (DGMS) durchgeführt (n = 100).
Ergebnisse: Bei der Nutzung der digitalen Technologien in den Veranstaltungen rangieren auf der obersten Stelle Präsentationstools, gefolgt von Lernmanagementsystemen, Videoangeboten sowie digitalen Texten. Die Teilnehmenden geben hinsichtlich der Nutzung unterschiedliche (Konferenz‑)Tools an. Das Erstellen von Lehrvideos bejahen 53 % der Befragten, Abstimmungstools) werden bis 50 % als unbekannt genannt. Als Herausforderungen werden digitale Infrastruktur der Hochschulen, fehlende didaktische Beratung/Unterstützung sowie rechtliche Fragen (Nutzungsrechte, Datenschutz) angegeben.
Schlussfolgerung: Neue Technologie werden vorwiegend für Wissenserwerb, Wissensvermittlung genutzt, selten zur Aktivierung von Studierenden und zur Gestaltung kollaborativer Lehr- und Lernarrangements sowie Neugestaltung von Lernaufgaben und Lernprozessen (individualisiertes Lernen). Welche der aktuell erprobten digitalen Lehr- und Lernformate zukünftig in der Hochschullehre zunehmend eingesetzt werden, hängt von vielen Faktoren ab, u. a. von digitaler Kompetenz sowie der Bereitschaft der Lehrenden und Lernenden die digitale Lernkultur mitzugestalten.
The removal of bacterial infections within the root canal system is still a challenge. Therefore, the cleansing effect of established and new irrigation-protocols (IP) containing silver diamine fluoride (SDF) 3.8% on the whole root canal system was analyzed using quantitative PCR (qPCR) and 4′,6-diamidino-phenylindole-(DAPI)-staining. Extracted human premolars were instrumented up to F2 (ProTaper Gold) under NaCl 0.9% irrigation and incubated with Enterococcus faecalis for 42 days. Subsequently, different ultrasonically agitated IP were applied to the roots: control (no irrigation), 1. NaOCl 3%, EDTA 20%, CHX 2%, 2. NaOCl 3%, EDTA 20%, 3. NaOCl 3%, EDTA 20%, SDF 3.8%, 4. SDF 3.8%, and 5. NaCl 0.9%. One half of the root was investigated fluorescent-microscopically with DAPI. The other half was grinded in a cryogenic mill and the bacterial DNA was quantified with qPCR. The qPCR results showed a statistically significant reduction of bacteria after the application of IP 1, 2, and 3 compared to the control group. While IP 4 lead to a bacterial reduction which was not significant, IP 5 showed no reduction. These data corresponded with DAPI staining. With qPCR a new molecular-biological method for the investigation of the complete root canal system was implemented. The novel IP 3 had an equally good cleansing effect as the already established IP.
Routing games over time are widely studied due to various applications, e.g., transportation, road and air traffic control, logistic in production systems, communication networks like the internet, and financial flows. In this article, we present a new competitive packet routing game with edge priorities motivated by traffic and transportation. In this model a set of selfishly acting players travels through the network over time. If the number of players who want to enter an edge at the same time exceeds the inflow capacity of this edge, then edge priorities with respect to the preceding edge are used to resolve these conflicts, which is similar to right-of-way rules in traffic. We analyze the efficiency of pure Nash equilibria, present an efficient algorithm for computing equilibria in symmetric games, and show that it is NP-hard to decide whether a Nash equilibrium exists in an asymmetric game. Furthermore, we address the problem of constructing optimal priorities.
Certifying Fully Dynamic Algorithms for Recognition and Hamiltonicity of Threshold and Chain Graphs
(2023)
Solving problems on graphs dynamically calls for algorithms to function under repeated modifications to the graph and to be more efficient than solving the problem for the whole graph from scratch after each modification. Dynamic algorithms have been considered for several graph properties, for example connectivity, shortest paths and graph recognition. In this paper we present fully dynamic algorithms for the recognition of threshold graphs and chain graphs, which are optimal in the sense that the costs per modification are linear in the number of modified edges. Furthermore, our algorithms also consider the addition and deletion of sets of vertices as well as edges. In the negative case, i.e., where the graph is not a threshold graph or chain graph anymore, our algorithms return a certificate of constant size. Additionally, we present optimal fully dynamic algorithms for the Hamiltonian cycle problem and the Hamiltonian path problem on threshold and chain graphs which return a vertex cutset as certificate for the non-existence of such a path or cycle in the negative case.
Supply chain collaboration has been widely discussed in the literature. With this maturity comes a plethora of heterogeneous research that is difficult to manage and navigate. This paper, therefore, applies a novel literature review approach based on text mining analyzing 10,556 articles to provide an overview of previous research themes and future directions of the field. The applied method enables researchers to systematically analyze and structure larger samples of research publications. It allocates articles to thematic clusters using a visual hierarchical clustering approach and subsequently aggregates them into nine overarching themes to determine potential research and insights for practice. Developments regarding research interest and attention within these themes are examined and journals publishing the most impactful articles are identified. The paper thus contributes to the field of Supply Chain Collaboration research by mapping its evolvement over the last five years and by deriving a research agenda for the next decade.
The aim of this study was to investigate the antimicrobial efficacy of different disinfection protocols in a novel Enterococcus faecalis biofilm model based on a visualization method and to evaluate the potential alteration of dentinal surface. A total of 120 extracted human premolars were allocated to 6 groups with different irrigation protocols. The assessment of the effectiveness of each protocol and the alteration of dentinal surface were visualized by using SEM and fluorescence microscopy (DAPI). A dense E. faecalis biofilm with a penetration depth of 289 μm (medial part of the root canal) and 93 μm (apical part) validated that the biofilm model had been successfully implemented. A significant difference between the 3% NaOCl groups and all the other groups in both observed parts of the root canal (p < 0.05) was detected. However, the SEM analysis revealed that the dentinal surface in the 3% NaOCl groups was severely altered. The established biofilm model and the visualization method based on DAPI are appropriate for bacterial quantification and evaluation of the depth effect of different disinfection protocols in the root canal system. The combination of 3% NaOCl with 20% EDTA or MTAD with PUI allows the decontamination of deeper dentine zones within the root canal but simultaneously alters the dentinal surface.
Sometimes cranioplasty is necessary to reconstruct skull bone defects after a neurosurgical operation. If an autologous bone is unavailable, alloplastic materials are used. The standard technical approach for the fabrication of cranial implants is based on 3D imaging by computed tomography using the defect and the contralateral site. A new approach uses 3D surface scans, which accurately replicate the curvature of the removed bone flap. For this purpose, the removed bone flap is scanned intraoperatively and digitized accordingly. When using a design procedure developed for this purpose creating a patient-specific implant for each bone flap shape in short time is possible. The designed skull implants have complex free-form surfaces analogous to the curvature of the skull, which is why additive manufacturing is the ideal manufacturing technology here. In this study, we will describe the intraoperative procedure for the acquisition of scanned data and its further processing up to the creation of the implant.
