Gutenberg Open Science (Univ. Mainz)
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Status Quo und Perspektiven der Informatik an Schulen und der Bildung von Lehrpersonen
Full text linkFortschreitende Digitalisierung erfordert grundlegende informatische Kompetenzen in nahezu allen Lebensbereichen. Eine Analyse aktueller Daten zeigt, inwiefern Schulen und die universitäre Lehramtsausbildung auf diese Herausforderungen reagieren und welche Chancen sich für die (Weiter-)Entwicklung einer zukunftsfähigen Informatikbildung ergeben
The association between air pollution exposure and childhood cancer : a scoping review about the challenges in epidemiological studies
No full textBackground and objective
Although several studies have investigated the association between various air pollutants and the risk of childhood cancer, particularly leukemia, results are still inconclusive. This scoping review aims to identify and discuss the main methodological challenges observed in publications addressing this topic.
Methodology
A literature search was conducted in two databases (MEDLINE and Web of Science), focusing on epidemiological studies that examine the association between air pollution exposure and childhood cancer with publication dates ranging from 2009 to 2024. To ensure completeness, we conducted citation tracking and a supplementary Google Scholar search. Relevant publications were evaluated regarding different methodological aspects.
Results
Two independent reviewers screened 1683 abstracts and finally evaluated 32 full-text articles based on predefined criteria. Additionally, two cohort studies were included from citation tracking and one case-control study from Google Scholar. Twenty-three studies investigated the association between air pollutants and childhood cancer, 19 of them were case-control studies. This design poses a risk of recall and selection biases. Many studies face challenges such as inconsistent air pollution measurements, varying exposure time frames, and different data sources. Furthermore, many studies under-adjust important confounders like socioeconomic status, radiation levels, urbanization, and parental smoking habits. These issues limit internal validity and make it difficult to draw firm conclusions about the association.
Conclusion
Further studies should use more robust methodologies including improved exposure assessment, larger study populations, and advanced statistics, to strengthen the association between air pollution and childhood cancer and inform public health policies
Natural product-like fragments unlock novel chemotypes for a kinase target─exploring options beyond the flatland
No full textIn this study, we utilized a high-performance soaking system of protein kinase A (PKA) to perform a crystallographic screening of a natural product-like fragment library. We resolved 36 fragment-bound structures, corresponding to a hit rate of 41%. Nine fragments bound within the ATP site, nine peripherally, and 18 interacted with both the ATP and peripheral sites. One fragment binds to the same site as the approved allosteric kinase inhibitor asciminib, while another induces an unexpected conformational change. Systematic database mining revealed that both the fragments and their natural product parents have not been previously associated with PKA or kinase activity. A scaffold/chemotype analysis further underscored their novelty. Cheminformatics analyses confirmed that these fragments occupy a distinct chemical space, enriched in saturation, spatial complexity and molecular three-dimensional character compared to kinase binders from reference data sets. These properties have previously been linked to increased selectivity, reduced CYP450 inhibition, and higher overall clinical success rates
It’s about time: empirical and theoretical investigations of temporal dynamics in stressor–strain relationships
No full textIn recent decades, the number of longitudinal and diary studies in the occupational literature has grown substantially, providing deeper insights into how stressors and strain are related over time and addressing questions about their temporal changes. This body of research recognizes that exposure to stressors and the experience of strain can be both chronic and stable, as well as subject to daily, weekly, or yearly fluctuations. Consequently, naturally occurring temporal ups and downs in stressors and strain, along with their reciprocal relationships, are increasingly considered in occupational stress research. Yet, despite these advances, the role of time remains underrepresented in theories that seek to describe and explain stressors, strain, and their interplay.
By explicitly acknowledging time in both empirical research and theoretical frameworks, we can deepen our understanding of how stressor–strain processes unfold and lay the groundwork for time-sensitive theorizing in occupational stress research. Building on this premise, the present dissertation investigates the empirical and theoretical understanding of the temporal dynamics in stressor–strain relationships and promotes the integration of time into occupational stress research and theory development. Specifically, it pursues three research objectives. First, it evaluates to which extent existing occupational stress theories account for time-related effects in stressor–strain research. Second, it examines and extends two established stressor–strain relationships from a time-sensitive empirical and theoretical perspective, focusing on (1) identifying trajectories of time pressure and their well-being relevance, informed by the effort–recovery model and conservation of resources theory, and (2) investigating reciprocal adaptive change processes between time pressure and emotional exhaustion, drawing on propositions from adaptation and conservation of resources theory. Third, it systematically reviews and synthesizes how time has been theoretically and empirically integrated into existing stressor–strain research.
To achieve these aims, two empirical studies and one systematic literature review were conducted. The first study applied an exploratory person-centered approach to examine which latent classes of time pressure trajectories occur for employees across one workweek as well as their relationship with well-being being at the end of the working week and start of the next week. Using data from 254 employees in a daily diary study across five consecutive workdays, findings revealed four qualitatively distinct trajectories that exhibited class-specific differences in Friday evening and Monday morning positive valence, calmness, and energetic arousal as well as Friday night sleep quality.
The second study explored whether employees adapt to emotional exhaustion and time pressure and how changes in levels of emotional exhaustion and time pressure relate over time, considering their reciprocal relationship. Findings of latent change score analyses on weekly diary data across eight workweeks demonstrated that employees (N = 252) adapted to both emotional exhaustion and time pressure. Further, this adaptive change was affected by the level of time pressure of the previous week, resulting in a reduced adaptation in emotional exhaustion, and vice versa, providing important information on the simultaneously occurring processes of adaptation and resource loss.
The systematic literature review focused on a synthesis of how time is theoretically and empirically integrated into stressor–strain studies (158 studies in 147 articles) published in four peer-reviewed journals between 2012 and 2021. Five time-related categories were identified that demonstrate how current literature applies time in theoretical propositions and methodology. Here, most research tends to address time-related questions from a methodological perspective rather than a theoretical one. The review identifies seven priorities for what time-sensitive theorizing needs in the future and addresses enduring challenges in capturing the temporal dynamics of stressor-strain relationships.
Together, the studies and review provide new empirical evidence and theoretical guidance on the temporal dynamics of occupational stress. They demonstrate that time is not merely a methodological consideration, but a fundamental dimension in explaining how stressors and strain develop, interact, and change. By embedding temporal thinking into occupational stress research and theory, this work advances a more nuanced and accurate understanding of stressor–strain processes and lays the foundation for future time-sensitive theorizing in the field.In den letzten Jahrzehnten hat die Zahl der Längsschnitt- und Tagebuchstudien in der arbeitspsychologischen Literatur erheblich zugenommen. Diese Studien liefern tiefere Einblicke in die zeitliche Beziehung zwischen Stressoren und Beanspruchung und befassen sich mit Fragen zu deren zeitlichen Veränderungen. Die Forschung erkennt an, dass sowohl die Exposition gegenüber Stressoren als auch die Erfahrung von Beanspruchung chronisch und stabil sein können, sich aber ebenso auf täglicher, wöchentlicher oder jährlicher Basis verändern können. Folglich werden die natürlich auftretenden zeitlichen Schwankungen von Stressoren und Beanspruchung sowie ihre wechselseitigen Beziehungen zunehmend in der arbeitspsychologischen Stressforschung berücksichtigt. Dennoch bleibt die Rolle der Zeit in Theorien, die Stressoren, Beanspruchung und deren Zusammenhang beschreiben und erklären wollen, bislang unterrepräsentiert.
Durch die explizite Berücksichtigung von Zeit sowohl in der empirischen Forschung als auch in theoretischen Rahmenkonzepten lässt sich unser Wissen zur Entwicklung von Stressor–Beanspruchungs-Prozessen vertiefen und die Grundlage für eine zeitsensitive Theoriebildung in der arbeitspsychologischen Stressforschung legen. Vor diesem Hintergrund untersucht die vorliegende Dissertation das empirische und theoretische Verständnis der zeitlichen Dynamiken in Stressor–Beanspruchungs-Zusammenhängen und fördert die Integration von Zeit in die arbeitspsychologische Stressforschung und Theoriebildung. Konkret verfolgt sie drei Forschungsziele: Erstens wird untersucht, inwieweit bestehende arbeitspsychologische Stresstheorien zeitbezogene Effekte in der Stressor–Beanspruchungs-Forschung berücksichtigen. Zweitens werden zwei etablierte Stressor–Beanspruchungs-Zusammenhänge aus einer zeitsensitiven empirischen und theoretischen Perspektive untersucht und erweitert, mit Schwerpunkt auf (1) der Identifikation von Zeitdruckverläufen und deren Bedeutung für das Wohlbefinden, basierend auf dem Effort–Recovery Model und der Conservation of Resources Theory, sowie (2) der Untersuchung reziproker adaptiver Veränderungsprozesse zwischen Zeitdruck und emotionaler Erschöpfung unter Rückgriff auf Annahmen der Adaptation Theory and Conservation of Resources Theory. Drittens erfolgt eine systematische Überprüfung und Synthese der theoretischen und empirischen Integration von Zeit in die bestehende Stressor–Beanspruchungs-Forschung.
Zur Erreichung dieser Ziele wurden zwei empirische Studien und eine systematische Literaturübersicht durchgeführt. Die erste Studie nutzte einen explorativen personenzentrierten Ansatz, um zu untersuchen, welche latenten Klassen von Zeitdruckverläufen bei Beschäftigten innerhalb einer Arbeitswoche auftreten und wie diese mit dem Wohlbefinden am Ende der Arbeitswoche und zu Beginn der folgenden Woche zusammenhängen. Anhand von Daten aus einer fünftägigen Tagebuchstudie mit 254 Beschäftigten wurden vier qualitativ unterschiedliche Verläufe identifiziert, die sich in ihrer positiven Valenz, Ruhe und energetischen Aktivierung am Freitagabend und Montagmorgen sowie in der Schlafqualität in der Freitagnacht unterschieden.
Die zweite Studie untersuchte, ob Beschäftigte über die Zeit auf das Ausgangslevel von emotionaler Erschöpfung und Zeitdruck zurückkehren (d.h. Adaptation) und wie sich Veränderungen in den Ausprägungen von emotionaler Erschöpfung und Zeitdruck gegenseitig beeinflussen. Latent Change Score Analysen auf Basis wöchentlicher Tagebuchdaten über acht Arbeitswochen (N = 252) zeigten, dass Beschäftigte sowohl bei emotionaler Erschöpfung als auch Zeitdruck auf das Ausgangslevel zurückkehrten. Darüber hinaus wurde diese Adaptation durch das Zeitdruckniveau der Vorwoche beeinflusst, was zu einer verringerten Anpassung der emotionalen Erschöpfung führte, und umgekehrt. Dies liefert wichtige Erkenntnisse zu den gleichzeitig ablaufenden Prozessen von Adaptation und Ressourcenverlust.
Die dritte Studie widmete sich einer Synthese darüber, wie Zeit theoretisch und empirisch in Studien zu Stressor–Beanspruchungs-Zusammenhängen integriert wird. Hierzu wurde eine systematische Literaturübersicht von 158 Studien aus 147 Artikeln durchgeführt, die zwischen 2012 und 2021 in vier führenden Fachzeitschriften erschienen sind. Dabei wurden fünf zeitbezogene Kategorien identifiziert, die aufzeigen, wie die aktuelle Literatur Zeit in theoretischen Annahmen und methodischen Ansätzen berücksichtigt. Es zeigte sich, dass die meisten Arbeiten zeitbezogene Fragestellungen eher aus methodischer als aus theoretischer Perspektive behandeln. Das Review benennt sieben zentrale Schwerpunkte, die eine zeitsensitive Theoriebildung künftig berücksichtigen sollte, und geht auf anhaltende Herausforderungen bei der Erfassung der zeitlichen Dynamiken von Stressor–Beanspruchungs-Zusammenhängen ein.
Zusammen liefern diese Studien neue empirische Befunde und theoretische Orientierung zur zeitlichen Dynamik von Arbeitsstress. Sie zeigen, dass Zeit nicht nur eine methodische Überlegung darstellt, sondern wichtig ist, um zu erklären wie Stressoren und Beanspruchung entstehen, miteinander interagieren und sich verändern. Indem zeitliche Perspektiven in die Forschung und Theorien zu Arbeitsstress integriert werden, trägt diese Arbeit zu einem differenzierteren und genaueren Verständnis von Stressor-Beanspruchungs-Prozessen bei und legt die Grundlage für eine zukünftige zeitsensible Theoriebildung in diesem Forschungsbereich.VIII, 190 Seiten ; Illustrationen, Diagramm
Archetypische Muster von Gesichtsfeldausfällen in der Oktopus-Perimetrie: klinische Korrelate und Struktur-Funktions-Analyse
No full textIV, 100 Seiten ; Illustrationen, Diagramm
Running ALPs across scales : effective field theories and phenomenology of axion-like particles
No full textThe Standard Model of particle physics (SM) is an astonishingly successful theory that describes nature with almost inconceivable accuracy. Yet, it is incomplete, as several hints point toward the existence of additional particles outside its field content. One of the most promising candidate for such a new state is the axion-like particle (ALP), a generalization of the axion, initially proposed to solve the strong CP problem. This thesis explores ALP effective theories and their phenomenological implications across different energy scales, divided into four parts. The first part is based on the ALP–SMEFT interference, where one-loop ALP exchange generates dimension-six SMEFT operators. By running these effects down to experimental scales and using existing bounds on SMEFT Wilson coefficients, strong model-independent constraints on ALP–SM couplings are derived that are compatible with or even surpass direct searches. In the second part, this concept is systematically extended to the low-energy effective field theory (LEFT), showing how ALPs can contribute to the (g−2)µ via the ALP–LEFT interference. Moving down to even lower energies at and below the scale of chiral symmetry breaking, a consistent ALP extension of chiral perturbation theory at next-to-leading order is constructed. Applying this framework to the flavor-violating decays K±→π±a provides the strongest constraints on ALP–SM couplings for ma ≲300 MeV. Finally, by running the modified RG equation of the quartic Higgs coupling up to the Planck scale, ALP influences on the electroweak stability are analyzed, as well as a possible gauge coupling unification scenario in the presence of this new particle.xv, 153 Seiten ; Illustrationen, Diagramm
Beam dynamics investigations for the second injection beamline of MESA
No full textThe project MESA (Mainz Energy-Recovering Superconducting Accelerator) is an unique electron accelerator placed at the Johannes Gutenberg University in Mainz, Germany. MESA will be a recirculating machine that achieves energy recovery in superconducting accelerating structures through multiple turns. The goal of the MESA project is to conduct experiments in many fields, such as particle physics, nuclear physics and other fundamental research. The accelerator has two different laser-driven electron sources (polarized and unpolarized) operating at 100 kV . The main polarized source STEAM (Small Thermalized Electron-source at Mainz) allows to produce spin-polarized electron beam and has been operating since the end of 2023. A second source MIST (MESA Injector Source Two) is planned for construction in the future. The peculiarity of the second source is that it was designed to produce electron beam with a high charge in the bunch. In future, this source and double Mott polarimeter will be arranged on the same height above the MESA main injector beamline. Therefore, a special parallel shifting beamline is required to transport a highly charged electron beam from the source MIST to the main MESA beamline. This work is dedicated to the design of such a transport channel. Simulations shown that the designed channel allow to compress and transport electron beam to the first acceleration section of MESA with up to 10mA of average current, which corresponds to charge of 7.7 pC in a bunch for an operating frequency 1.3 GHz.100 Seiten ; Illustrationen, Diagramm
Raw data for "Photochemical cyclization of tertiary buta-2,3-dienamides to β-lactams upon triplet energy transfer"
No full textA series of N,N-disubstituted buta-2,3-dienamides was prepared from 3-butynoic acid and probed as substrates in a light-induced photocyclization. It was found that xanthen-9-one (10 mol%) promotes the desired reaction to 3-vinyl-substituted 2-azetidinones (beta-lactams) when performed at lambda = 350 nm in acetonitrile as the solvent. Evidence was collected by transient absorption spectroscopy that the catalyst promotes excitation of the allene amide to its triplet state by Dexter energy transfer. Upon intramolecular hydrogen atom transfer from one of the nitrogen substituents, the ensuing 1,4-diradical undergoes C-C bond formation to the lactam product. If the substituent at the nitrogen atom is a primary benzyl group, the product displays a stereogenic center in 4-position and is formed exclusively as the trans-product (eleven examples, 18-73% yield). If the substituent is secondary, 4,4-disubstituted products are formed. If the buta-2,3-dienamide is substituted at the terminal carbon atom, the substituent at C3 in the 2-azetidinone is an (E)-configured alkenyl group. Two alternative reaction pathways were observed, i.e. an intramolecular para photocycloaddition for N-phenyl substituted substrates and an elimination from the 1,4-diradical intermediate. The vinyl group at C3 can serve as useful handle for consecutive transformations.Experiment
Studierendeninteressen im Lehramt Informatik
No full textWährend Informatik als schulisches Pflichtfach in immer mehr Bundesländern eingeführt wird, besteht weiterhin ein erheblicher Lehrkräftemangel. Attraktive Berufsalternativen außerhalb des Bildungswesens stellen die Lehramtsausbildung vor Herausforderungen. Mehrere qualitative Befragungen geben Aufschluss über die Motive für die Wahl eines Lehramtsstudiums sowie mögliche Strategien zur Gewinnung zusätzlicher Interessierter
