Zeitaufgelöste Untersuchungen zum oxidativen Abbau selektiv laserphotolytisch erzeugter Alkoxy-Radikale unter NOx-reichen Bedingungen der Troposphäre

In der vorliegenden Arbeit sind Prozesse des oxidativen Abbaus ausgewählter VOCs (Volatile Organic Compounds) mit Hilfe laserspektroskopischer Verfahren untersucht worden. Im ersten Teil der Arbeit wurden Geschwindigkeitskonstanten der Reaktionen einzelner n-Butoxy- und n-Pentoxy-Radikale quantitativ bestimmt. Der verwendete experimentelle Aufbau erlaubte den gleichzeitigen und zeitaufgelösten Nachweis von NO2 und OH-Radikalen. NO2 wurde mittels cw-LiF (Laser induzierte Fluoreszenz) nach Anregung bei einer Wellenlänge von 488 nm de-tektiert. Die Anregungswellenlänge stellte ein Argon-Ionenlaser bereit. Es konnte eine Nach-weisgrenze von etwa 1 x 1010 cm-3 erreicht werden. Im Gegensatz dazu wurden OH-Radikale durch Laserlangwegabsorption bei einer Wellenlänge von 308 nm nachgewiesen. Als Analy-senlichtquelle diente ein intern frequenzverdoppelter Ring-Farbstofflaser. Zur Verbesserung der Nachweisgrenze wurde der Laserstrahl in eine Multireflexionszelle nach White eingespie-gelt, so dass Absorptionsweglängen von ca. 40 m realisiert werden konnten. Diese führten zu einer Nachweisgrenze für OH-Radikale von 1 x 109 cm-3. Die Bestimmung individueller Geschwindigkeitskonstanten erfolgte mittels numerischer Simulation der experimentell gemessenen Konzentrations-Zeit-Profile. Dabei wurden die zu bestimmenden Geschwindigkeitskonstanten solange variiert, bis die simulierten Profile optimal an die gemessenen angepasst waren. Alle untersuchten Reaktionen wurden durch die Excimer-Laserphotolyse eines Bromal-kans bei einer Wellenlänge von 248 nm gestartet. Die primär gebildeten n-Alkyl-Radikale rea-gierten in Gegenwart von Sauerstoff und NO sehr schnell zu den entsprechenden Alkoxy-Ra-dikalen. Neben den Untersuchungen einzelner Alkoxy-Radikalreaktionen konnten in der vorlie-genden Arbeit erstmals NOCON-Faktoren direkt experimentell gemessen werden. Unter dem NOCON-Faktor eines VOCs versteht man das Verhältnis aus erzeugter NO2-Menge und abge-bauter VOC-Menge. Da NO2 unter den Strahlungsverhältnissen der Troposphäre sehr schnell in NO und O photolysiert wird, wobei über die Reaktion O + O2 ? O3 Ozon aufgebaut wird, erlauben NOCON-Faktoren Aussagen über die zeitliche Entwicklung der O3-Konzentration im Zuge einer photochemischen Smogepisode

Design Guidelines for Enterprise Software Training in Higher Education Based on Technology-Mediated Learning

There is an increasing demand for a qualified future workforce in the enterprise software (ES) domain, for which students should be prepared. However, due to the complexity of ES, many lecturers lack the skills to practically integrate ES into their teaching activities. ES training must be investigated holistically to address this issue, integrating the perspectives of the involved actors. Therefore, the research field of technology-mediated learning (TML) offers valuable concepts. In this paper, we first identify and present five main concepts of TML performance based on related literature. Second, we present findings from a single-case study conducted within the global academic alliance program of the ES company SAP. The program’s objective is to demonstrate the practical application of ES to students through lecturers. Unlike previous research, we consider the students’ perspective and incorporate the viewpoints of lecturers and subject matter experts (SMEs) who train the lecturers to create a comprehensive overview. Based on the insights from TML literature and the case study, we present design guidelines for ES training that take into account TML concepts, actors’ perspectives, and training aspects. Our findings highlight the universal applicability of TML in the practical context of designing ES training in higher education

Intelligent group movement and selection in realtime strategy games

Movement of groups in realtime strategy games is often a nuisance: Units travel and battle separately, resulting in huge losses and the AI looking dumb. This applies to computer as well as human commanded factions. We suggest to tackle that by using flocking improved by influence-map based pathfinding which leads to a much more natural and intelligent looking behavior. A similar problem occurs if the computer AI has to select groups to combat a specific target: Assignment of units to groups, especially for multiple enemy groups, is often suboptimal when units have very different attack skills. This can be cured by using offline prepared self-organizing feature maps that use all available information for looking up good matches. We demonstrate that these two approaches work well separately, but also that they go together very naturally, thereby leading to an improved and - via parametrization - very flexible group behavior. Opponent AI may be strenghtened that way as well as player-supportive AI. A thorough experimental analysis supports our claims

The Future of Digital Health with Federated Learning

Data-driven Machine Learning has emerged as a promising approach for building accurate and robust statistical models from medical data, which is collected in huge volumes by modern healthcare systems. Existing medical data is not fully exploited by ML primarily because it sits in data silos and privacy concerns restrict access to this data. However, without access to sufficient data, ML will be prevented from reaching its full potential and, ultimately, from making the transition from research to clinical practice. This paper considers key factors contributing to this issue, explores how Federated Learning (FL) may provide a solution for the future of digital health and highlights the challenges and considerations that need to be addressed.Comment: This is a pre-print version of https://www.nature.com/articles/s41746-020-00323-

Nanofasern als neuartige Träger für flüchtige Signalstoffe zur biotechnischen Regulierung von Schadinsekten im integrierten und ökologischen Landbau

Using nanofibers as dispensers for pheromones and kairomones in plant protection for disrupting insect chemical communication is a novel approach aiming at popularizing this technique in organic and integrated plant production. Expected advantages of the nanofibers are highly controlled spatiotemporal release rates of pheromones / kairomones, improved climatic stability, and mechanized application. Dispenser types used so far show deficiencies in one or more of these requirements. Mechanical application of pheromones is a new approach to reduce the costs of manual labour and therefore the environmentally compatible, highly specific and efficient technique of mating disruption may become an alternative to the use of synthetic pesticides in integrated pest management. The nanofibers are highly elastic, which prevents breakoff of smaller pieces, and polymers used are biocompatible. Due to the scale of nanofibers the mass input both for pheromones and for polymeric nanofibers is very low. Major environmental benefits are high control specificity, very low concentrations of residues and reduced risk of development towards insect resistance

Impact of Sleep Apnea on Cardioembolic Risk in Patients With Atrial Fibrillation: Data From the ESADA Cohort

Background and purpose: An accurate determination of the cardioembolic risk in patients with atrial fibrillation (AF) is crucial to prevent consequences like stroke. Obstructive sleep apnea (OSA) is a known risk factor for both AF and stroke. We aim to explore a possible association between OSA and an increased cardioembolic risk in patients with AF.Methods: We assessed data from the ESADA (European Sleep Apnea Database) cohort where patients with known AF and OSA were included. Parameters of OSA severity and related hypoxia like lowest Spo2 and 4% oxygen desaturation index were analyzed. Patients were stratified according to their cardioembolic risk estimated with the CHA2DS2-VASc score.Results: From the initial cohort of 14 646 patients, a final set of 363 patients were included in the analysis. Indices of hypoxia during sleep were associated with increased CHA2DS2-VASc score (4% oxygen desaturation index 17.9 versus 29.6 versus 30.5 events/hour and the lowest Spo2 81.2 versus 77.8 versus 77.5% for low, moderate, and high cardioembolic risk, respectively, PConclusions: These results support the potential role of OSA-related hypoxia in the risk for cardioembolic complications such as stroke in patients with AF.</p