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Aberration-driven tilted emission in degenerate cavities
No full textThe compensation of chromatic dispersion opened new avenues and extended the level of control upon pattern formation in the temporal domain. In this paper, we propose the use of a nearly degenerate laser cavity as a general framework allowing for the exploration of higher contributions to diffraction in the spatial domain. Our approach leverages the interplay between optical aberrations and the proximity to the self-imaging condition, which allows us to cancel or reverse paraxial diffraction. As an example, we show how spherical aberrations materialize into a transverse bi-Laplacian operator and, thereby, explain the stabilization of temporal solitons traveling off-axis in an unstable mode-locked broad-area surface-emitting laser. We disclose an analogy between these regimes and the dynamics of a quantum particle in a double-well potential
An Alternative Treatment Option for Blauth III B Thumb Hypoplasia—Thumb Stabilization with Iliac Crest Bone Graft and Intermetacarpal Arthrodesis
No full textThumb hypoplasia modified Blauth III B is usually treated by pollicization or, less commonly, by toe transfer. Both procedures always result in the resection of a body part, but with good cosmesis and acceptable function. We describe an intermetacarpal I/II arthrodesis with autologous bone graft augmentation to lengthen and stabilize the loose thumb. Clinical data were collected from nine patients, median age at surgery 3 years 8 months, with more than 7 years of follow-up. The results showed a grip strength on the Jamar dynamometer of approximately 61% of the unoperated hand. The Quick-DASH score was 11. The reconstructed thumb was 0.8 cm thinner and 1.9 cm shorter. Overall satisfaction on the VAS, with an average of 1.5 out of 10, is excellent with a partially usable thumb on a hand with five rays. The described procedure is a reliable treatment option with satisfactory results. In addition, none of the patients lost pincer grip between the second and third digit, but their thumb gained new function. Especially in environments where physical integrity has a high value, thumb construction instead of replacement could be considered
Analyse der Volumenänderungen nach Aortenbogenersatz mittels Frozen-Elephant-Trunk und konventionellem Elephant-Trunk bei akuter Aortendissektion Typ A
No full textDie Dissertation mit dem Titel "Analyse der Volumenänderungen nach Aortenbogenersatz mittels Frozen-Elephant-Trunk und konventionellem Elephant-Trunk bei akuter Aortendissektion Typ A" untersuchte die Volumenänderungen der Aorta nach einem Aortenbogenersatz bei Patienten mit akuter Typ-A-Aortendissektion. Dabei wurden zwei Techniken verglichen: die konventionelle Elephant-Trunk-Technik (CET) und die Frozen-Elephant-Trunk-Technik (FET). Die Studie analysierte retrospektiv die Volumina des wahren, falschen und gesamten Lumens der Aorta mittels Computertomographie-Angiographie (CTA) zu vier Zeitpunkten: präoperativ, bei Entlassung, nach einem Jahr und nach zwei Jahren. Die Ergebnisse zeigten, dass die FET-Technik gegenüber der CET-Technik hinsichtlich der Reduktion von Falschlumenveränderungen und der Anzahl der Reinterventionen überlegen ist. Eine langfristige Beurteilung der Ergebnisse steht noch aus
Auf- und Ausbau multiplikativen Denkens mit der Applikation TouchTimes:DigiHet: Digital Heterogenität beachten. Individuelles Lernen mathematischer Kompetenzen digital unterstützen
No full textMultiplikatives Denken ist die Grundlage für erfolgreiches Lernen mathematischer Inhalte wie beispielsweise Proportionen, Brüche und Dezimalzahlen und sollte bereits in der Primarstufe auf- und ausgebaut werden. Die Autorin zeigt durch eine fachdidaktische Begründung auf, wie und warum die Applikation TouchTimes (Jackiw & Sinclair, 2019) als geeignetes Artefakt zur Erarbeitung des Lerngegenstandes multiplikatives Denken dient. Vor dem Hintergrund der heterogenen Schülerschaft werden in dieser fachdidaktischen Entwicklungsforschung zum einen die Entwicklung eines Lehr-Lern-Arrangements und zum anderen die Forschungsergebnisse hinsichtlich multiplikativen Denkens von Drittklässlerinnen und Drittklässler fokussiert.In the research project 'DigiHet', a learning environment was developed to establish and
expand the multiplicative thinking of primary school students. Therefore, the Artifact-
Centric Activity Theory (ACAT) (Ladel & Kortenkamp, 2016) guided the planning, which
results in a new model of the Design-Research, namely Gmünder Modell. The ACATModel
significantly helped to keep in mind the necessary components for the (further)
development of the learning environment. These components are, among others, the
student, the heterogeneous students, the teacher acting in a didactic way, the
mathematical object and the artifact. To elaborate on the mathematical object of
multiplicative thinking, the application TouchTimes (Jackiw & Sinclair, 2019) turned out to
be an appropriate artifact. While in the ACAT-Model the artifact is focused, the Design-
Research concentrates on the mathematical object. Diagnostic interviews were used to
elicit the multiplicative thinking of the heterogeneous students and subsequently,
evaluated in the context of a qualitative content analysis. Based on the research results
and existing literature, a design principle was established regarding the demand and
promotion of multiplicative thinking
Bronchoscopist-Directed Continuous Flow Propofol Based Analgosedation during Flexible Interventional Bronchoscopy and EBUS
No full textSedation techniques in interventional flexible bronchoscopy and endobronchial ultrasound-guided transbronchial-needle aspiration (EBUS-TBNA) are inconsistent and the evidence for required general anesthesia under full anesthesiologic involvement is scarce. Moreover, we faced the challenge of providing bronchoscopic care with limited personnel. Hence, we retrospectively identified 513 patients that underwent flexible interventional bronchoscopy and/or EBUS-TBNA out of our institution between January 2020 and August 2022 to evaluate our deep analgosedation approach based on pethidine/meperidine bolus plus continuous flow adjusted propofol, the bronchoscopist-directed continuous flow propofol based analgosedation (BDcfP) in a two-personnel setting. Consequently, 502 out of 513 patients received BDcfP for analgosedation. We identified cardiovascular comorbidities, chronic obstructive pulmonary disease, and arterial hypertension as risk factors for periprocedural hypotension. Propofol flow rate did not correlate with hypotension. Theodrenaline and cafedrine might be used to treat periprocedural hypotension. Moreover, midazolam might be used to support the sedative effect. In conclusion, BDcfP is a safe and feasible sedative approach during interventional flexible bronchoscopy and EBUS-TBNA. In general, after the implementation of safety measures, EBUS-TBNA and interventional flexible bronchoscopy via BDcfP might safely be performed even with limited personnel
Caustic networks with customized intensity statistics
No full textControlling random light is a key enabling technology that pioneered statistical imaging methods like speckle microscopy. Such low-intensity illumination is especially useful for bio-medical applications where photobleaching is crucial. Since the Rayleigh intensity statistics of speckles do not always meet the requirements of applications, considerable effort has been dedicated to tailoring their intensity statistics. A special random light distribution that naturally comes with radically different intensity structures to speckles are caustic networks. Their intensity statistics support low intensities while allowing sample illumination with rare rouge-wave-like intensity spikes. However, the control over such light structures is often very limited, resulting in patterns with inadequate ratios of bright and dark areas. Here, we show how to generate light fields with desired intensity statistics based on caustic networks. We develop an algorithm to calculate initial phase fronts for light fields so that they smoothly evolve into caustic networks with the desired intensity statistics during propagation. In an experimental demonstration, we exemplarily realize various networks with a constant, linearly decreasing and mono-exponential probability density function
Die WWU und Corona – Start ins zweite Digitalsemester:Interview mit Prof. Dr. Johannes Wessels
No full textEnde Oktober ist die WWU in einen „eingeschränkten Betrieb“ gewechselt – zum zweiten Mal. Die Lehre findet wie bereits im vergangenen Sommersemester nun größtenteils digital statt. Was das für die Studierenden und speziell für die Studienanfänger bedeutet, ob es Hoffnung auf Präsenzlehre im aktuellen Wintersemester gibt und wie die Entscheidungen über die Corona-Maßnahmen getroffen werden, beantwortet Rektor Prof. Dr. Johannes Wessels im Podcast. Zudem gibt er Einblicke in die Arbeit der Krisenstäbe, bilanziert das vergangene Semester und erklärt, was im Falle eines Shutdowns geschehen würde. Schließlich schildert er die Pläne der WWU zum weiteren Umgang mit ihrem Namensgeber, Kaiser Wilhelm II.
Do a learner’s L1 and L2 change with increasing L3 exposure? Investigating regressive phonological cross-linguistic influence in adolescent and adult L3 learners
No full textDiese Studie untersucht die phonologische Entwicklung von sieben Jugendlichen und sieben Erwachsenen in ihrer Erst- (L1), Zweit- (L2) und Drittsprache (L3) im Verlauf des ersten Jahres des schulischen Lernens der L3. Ziel war es, Veraenderungen in den bereits vorhandenen Sprachen der Lernenden als Folge des zunehmenden L3-Inputs und -Gebrauchs zu identifizieren. Vier Aussprachemerkmale in allen Sprachen der Lernenden wurden sowohl auditiv als auch akustisch analysiert, um feingranulare Modifikationen aufzuspueren. Diese Studie ist damit die erste, welche die mehrsprachige Entwicklung zweier Altersgruppen longitudinal mit innovativen Methoden zur Verfolgung von phonologischen Veraenderungen untersucht. Bei den meisten Lernenden wurden im Laufe der Zeit Aenderungen der Aussprache sowohl in der L1 als auch der L2 festgestellt. Dies zeigt, dass alle Sprachen einer Person als Teil eines dynamischen Systems betrachtet werden sollten, das sich staendig wandelt. Darueber hinaus waren die individuellen Lernverlaeufe in den verschiedenen Sprachen weitgehend non-linear. Diese Ergebnisse unterstreichen daher die Notwendigkeit, bei der Untersuchung von Phaenomenen im Zusammenhang mit mehrsprachiger Sprachentwicklung vor allem auf prozessorientierte Ansaetze zurueckzugreifen.This study investigates the phonological development of seven adolescents and seven adults in their first (L1), second (L2), and third language (L3) over the course of their first year of L3 learning. It specifically explored modifications to the learners' already existing languages as a result of increasing L3 exposure and use. Four pronunciation features in all of the learners' languages were analyzed auditorily as well as acoustically in order to trace fine-grained changes. As such, this study is the first to explore the multilingual development of two age groups in a longitudinal manner using cutting-edge methodology for investigating phonological developments. For most learners, changes over time in both their L1 and L2 were detected. This shows that all of a speaker's languages should be seen as part of a dynamic system, undergoing continuous change. Moreover, the multilingual learning trajectories encountered in this study were largely non-linear. These findings therefore stress the need to focus on process-oriented approaches when studying phenomena related to multilingual language development
Do They Look Where They Go? Gaze Classification During Walking
No full textIn many applications of human-computer interaction a prediction of the human's next intended action is highly valuable. For locomotor actions, in order to control direction and orientation of the body a walking person relies on visual input obtained by eye and head movements. The analysis of these parameters can be used to infer the intended goal of the walker. However, such a prediction of human locomotion intentions is a challenging task since interactions between these parameters are non-linear and highly dynamic. Distinguishing gazes on future waypoints from other gazes can be a helpful source of information. We employed LSTM models to investigate if gaze and walk data can be used to predict whether walkers are currently looking at locations along their future path or whether they are looking in a direction that is away from their future path. Our models were trained on egocentric data from a virtual reality experiment in which 18 participants walked freely through a virtual environment while performing various tasks (walking along a curved path, avoiding obstacles and searching for a target). The dataset included only egocentric features (position, orientation and gaze) and no information about the environment. These features were used to determine when gaze was directed at future waypoints and when not. The trained model achieved an overall accuracy of 80%. Biasing the model to focus on correct classification of gazes away from the path increased the detection rate of these gazes to 90%. An analysis of model performance in the different walking task showed that accuracy was highest (85%) for curved path walking and lowest (73%) for the target search task. We conclude that online gaze measurements during walking can be used to estimate a walker's intention and to determine whether they look at the target of their future trajectory or away from it
Comparison of the Accuracy of a Mounting Fixture for Dental Implants for Implant Position Transfer and Open-Tray Implant Level Impression—An In Vitro Study
No full textThe accuracy for the implant position transfer of a mounting fixture and a standardized open-tray implant level impression was compared. Ten aluminum master models with four implant analogs placed in different angulations were fabricated. By performing an open-tray implant level impression stone casts were produced. The master models and stone casts were scanned (comparison group one) using a laboratory scanner. Deviations in the scan body surface were determined in the form of mean (absolute) point distances and (signed) surface distances. The same procedure was performed with a screwed transfer and by fixing the posts of the mounting fixture (comparison group two). The mounting device was applied to each master model and scanned in a fixed and detached state (comparison group three). In a point comparison, the open-tray implant level impression showed mean deviations of 43.6 µm and a mounting fixture of 44.6 µm with no significant differences (p 0.05). Within the limits of this study, the mounting fixture transferred the implant position with the same accuracy as the open-tray implant level impression with respect to point deviations