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Shedding light on the shortness of sight
(2024) Hönekopp, Astrid; Weigelt, Sarah; Gerken, Jens
The global rise in myopia prevalence sets off certain alarm bells, as myopia not only imposes a substantial economic and financial burden on affected individuals and the public, but can also entail further negative consequences, such as secondary pathologies as well as reduced quality of life and educational outcomes. The development of the most common type of myopia is connected to both school age as a critical period and bright light exposure as a key protective factor. Accordingly, timely public health interventions need up-to-date information on myopia prevalence and its associations, as well as the relationship with bright light exposure, which is often investigated with wearable light meters.
This dissertation addresses in six studies three main research objectives to fill crucial gaps in myopia research: (1) providing up-to-date myopia prevalence data for German youth, (2) evaluating the utility of online questionnaires in epidemiological research, and (3) advancing methodological understanding of light meter use in myopia research.
In Study 1, refractive measurements of > 1,500 school students in Germany revealed a myopia prevalence of 8.4% in primary school students (mean age 9.30 years) and 19.5% in secondary school students (mean age 14.99 years) as well as a large proportion of uncorrected myopia (51.2% and 43.3%, respectively). Study 2 evaluated five recruitment strategies for an online parent questionnaire on children’s spectacle ownership, identifying varying (dis)advantages per strategy related to aspects such as representativeness, efficiency and costs. Study 3 analyzed the questionnaire data from > 1,700 children, demonstrating discrepancies in prevalence rates of corrected myopia compared to direct measurements, thereby indicating biases in the questionnaire data.
A comprehensive literature review in Study 4 examined the use of various wearable light meters in myopia research, revealing significant variability in device specifications and research methodologies, which likely contributes to inconsistent findings in the field. Study 5 directly compared the performance of multiple light meters worn simultaneously, showing similar light exposure patterns but substantial differences in absolute lux values and in the frequently investigated distinction of indoor and outdoor environments. Study 6 explored the development of a custom-made light meter, concluding that while feasible, commercial devices may be more practical for most research needs.
This dissertation’s findings highlight the necessity for continuous monitoring of myopia prevalence, especially uncorrected myopia, and emphasize the importance of methodological rigor in research on light exposure and myopia. Recommendations include routine refractive screenings in schools and careful consideration of light meter selection and methodology in future studies on light-myopia associations. These insights address both future research efforts as well as public health strategies aiming at myopia.
Few-photon SUPER: quantum emitter inversion via two off-resonant photon modes
(2025-01-21) Richter, Quentin W.; Kaspari, Jan M.; Bracht, Thomas K.; Yatsenko, Leonid; Axt, Vollrath Martin; Rauschenbeutel, Arno; Reiter, Doris E.
With the realization of controlled quantum systems, exploring excitations beyond the resonant case opens new possibilities. We investigate an extended Jaynes-Cummings model in which two nondegenerate photon modes are coupled off resonantly to a quantum emitter. This allows us to identify few-photon scattering mechanisms that lead to a full inversion of the emitter while transferring off-resonant photons from one mode to another. This behavior is connected to recent measurements of a two-level emitter scattering two off-resonant photons simultaneously. Furthermore, our results can be understood as a quantized analog of the recently developed off-resonant quantum control scheme known as swing-up of quantum emitter (SUPER). Our intuitive formalism gives deeper insight into the interaction of a two-level emitter with off-resonant light modes with the prospect of novel photonic applications.
Warum sind Konfidenzellipsen eigentlich Ellipsen? – Vernetzung zwischen Stochastik und Geometrie
(Gesellschaft für Didaktik der Mathematik, 2025-02-05) Humenberger, Hans
In den letzten Jahren ist in der Literatur der Begriff der Konfidenzellipse vermehrt in Erscheinung getreten (bei Konfidenzintervallen für eine unbekannte Wahrscheinlichkeit p). Damit kann gut der Unterschied zwischen Prognose- und Konfidenzintervallen veranschaulicht werden. Die Tatsache, dass es sich dabei um eine Ellipse handelt, ist aus stochastischer Sicht eigentlich nicht wichtig, daher wird das auch kaum irgendwo näher hinterfragt bzw. begründet. Im Vortrag wird versucht es trotzdem zu erklären, und zwar auf möglichst anschauliche und elementare Weise.
Pressure robust Finite Element discretizations of the nonlinear Stokes Equations
(2025-01-27) Diening, Lars; Hirn, Adrian; Kreuzer, Christian; Zanotti, Pietro
We present first-order nonconforming Crouzeix-Raviart discretizations for the nonlinear generalized Stokes equations with (r, ε)-structure. Thereby the velocity-errors are independent of the pressure-error; i.e., the method is
pressure robust. This improves suboptimal rates previously experienced for non pressure robust methods.
Beschreiben im Biologieunterricht
(2022) Bayrak, Cana