Analysis, Modeling and Dynamic Optimization of 3D Time-of-Flight Imaging Systems

The present thesis is concerned with the optimization of 3D Time-of-Flight (ToF) imaging systems. These novel cameras determine range images by actively illuminating a scene and measuring the time until the backscattered light is detected. Depth maps are constructed from multiple raw images. Usually two of such raw images are acquired simultaneously using special correlating sensors. This thesis covers four main contributions: A physical sensor model is presented which enables the analysis and optimization of the process of raw image acquisition. This model supports the proposal of a new ToF sensor design which employs a logarithmic photo response. Due to asymmetries of the two read-out paths current systems need to acquire the raw images in multiple instances. This allows the correction of systematic errors. The present thesis proposes a method for dynamic calibration and compensation of these asymmetries. It facilitates the computation of two depth maps from a single set of raw images and thus increases the frame rate by a factor of two. Since not all required raw images are captured simultaneously motion artifacts can occur. The present thesis proposes a robust method for detection and correction of such artifacts. All proposed algorithms have a computational complexity which allowsreal-time execution even on systems with limited resources (e.g. embeddedsystems). The algorithms are demonstrated by use of a commercial ToF camera

EGFL7 meets miRNA-126: an angiogenesis alliance

Blood vessels form de novo through the tightly regulated programs of vasculogenesis and angiogenesis. Both processes are distinct but one of the steps they share is the formation of a central lumen, when groups of cells organized as vascular cords undergo complex changes to achieve a tube-like morphology. Recently, a protein termed epidermal growth factor-like domain 7 (EGFL7) was described as a novel endothelial cell-derived factor involved in the regulation of the spatial arrangement of cells during vascular tube assembly. With its impact on tubulogenesis and vessel shape EGFL7 joined the large family of molecules governing blood vessel formation. Only recently, the molecular mechanisms underlying EGFL7's effects have been started to be elucidated and shaping of the extracellular matrix (ECM) as well as Notch signaling might very well play a role in mediating its biological effects. Further, findings in knock-out animal models suggest miR-126, a miRNA located within the egfl7 gene, has a major role in vessel development by promoting VEGF signaling, angiogenesis and vascular integrity. This review summarizes our current knowledge on EGFL7 and miR-126 and we will discuss the implications of both bioactive molecules for the formation of blood vessels

Feldenkrais to Improve Interoceptive Processes and Psychological Well-being in Female Adolescent Ballet Dancers: A Feasibility Study

The Feldenkrais Method® (FM) is a form of somatic education aiming to increase brain-body communication, reportedly via interoceptive mechanisms. Although empirically proven to improve perceived interoceptive ability and psychological well-being in adults, feasibility in adolescents remains unclear. We therefore used a combined randomized control-group pretest-posttest design with qualitative interviews to explore the feasibility of an eight-week FM intervention to enhance interoceptive processes and psychological well-being in a population of adolescent female recreational ballet dancers. Participants’ (N = 12, Mage = 14.25 ± 1.29) interoceptive accuracy, perceived interoceptive ability, and psychological well-being were measured pre- and post-intervention, followed by individual interviews. Interview responses demonstrated high enjoyment, increased perceived embodied criticality, and reduced social comparison, supported by a significant increase in self-reported attention regulation (p = .042) in the intervention group. These preliminary findings support the feasibility of FM in this population and thus warrant further research using well-powered randomized controlled trials

COVID-19: Physical Activity and Quality of Life in a Sample of Swiss School Children during and after the First Stay-at-Home.

COVID-19 restrictions and the instructions to stay at home (SaH) may have had an impact on child behavior including physical activity (PA) and health-related quality of life (HRQoL) in Switzerland. Therefore, we investigated PA and HRQoL during and after the SaH in 57 Swiss school children aged 7 to 12 years (M = 10.44; SD = 1.34). PA was measured using accelerometry (Actigraph GT3X) and HRQoL using the Kid-KINDLR questionnaire. During and post data was compared using paired sample t-tests. Independent t-tests were used to compare the HRQoL of physically active children with non-physically active children. PA in light (d = -0.56), moderate (d = -0.44), moderate-to-vigorous (d = -0.28) as well as overall HRQoL (d = -0.66), psychological well-being (d = -0.48), self-esteem (d = -0.39), friends (d = -0.70) and everyday functioning (d = -0.44), were significantly lower during SaH than afterwards. Children who adhered to PA recommendations (+60 min of moderate-to-vigorous PA) during SaH had a better overall HRQoL (d = 0.61) and psychological well-being (d = 0.56) than those who did not. Since PA levels and HRQoL were lower during SaH compared to afterwards, it seems that the restrictions negatively impacted children's PA and HRQoL. During future SaHs, promoting children's PA and HRQoL seems important

Sportmotorische Leistungsfähigkeit und schulische Leistung – Zum mediierenden Effekt der exekutiven Funktionen

Die sportmotorische Leistungsfähigkeit (SMLF) gilt in jüngster Zeit als ein Prädiktor für schulische Leistung (SL) (Diamond, 2013). Um die Frage zu beantworten, wie denn zwei auf den ersten Blick so distale Merkmale zusammenhängen sollen, werden unterschiedliche erklärende Variablen diskutiert, wobei die kognitive Stimulationshypothese die exekutiven Funktionen (EF) als mediierende Variable im Zusammenhang zwischen SMLF und SL postuliert. Die Annahme hierbei ist, dass die mit komplexen motorischen Kontrollprozessen einhergehende kognitive Beanspruchung bei einem wiederholten Ausführen von nicht-automatisierten sportbezogenen Handlungen zu einer Aktivierung und somit Förderung der EF führt (Best, 2010). Der mediierende Effekt der EF im Zusammenhang zwischen der SMLF und der SL wird seit einigen Jahren in der Literatur diskutiert und wird im Folgenden innerhalb einer längsschnittlichen Untersuchung getestet. Im Rahmen der Studie SpuK wurden 237 Primarschulkinder (52.3% ♀; 11.31 ± 0.62 Jahre) zu drei Messzeitpunkten in ihrer SMLF (T1) und ihren EF (T2) getestet. Zur Ermittlung der SMLF wurden drei sportmotorische Tests in den Bereichen Koordination, Ausdauer und Schnellkraft durchgeführt. Die EF Inhibition, kognitive Flexibilität und Arbeitsgedächtnis wurden computerbasiert über den N-Back- und Flanker-Test operationalisiert. Zusätzlich wurde die SL (T3) mittels objektiver Schulleistungstests erhoben. Um die Hauptfragestellung zu prüfen, wurde eine bootstrapping basierte Mediationsanalyse in AMOS durchgeführt. Das Strukturgleichungsmodell (2 (22, N=237)=30.357, p=.110; CFI=.978) weist eine zufriedenstellende Anpassungsgüte auf. Erwartungsgemäss zerfällt der Zusammenhang innerhalb des Mediationsmodells zwischen der SMLF und der SL, alsbald die EF ins Modell aufgenommen werden (β=.16, p= .634). Sowohl der Zusammenhang zwischen der SMLF und den EF (β=.38, p= .039), als auch der Zusammenhang zwischen den EF und der SL fallen signifikant aus (β=.91, p=.001) und ergeben dabei eine volle Mediation über den indirekten (p=.021) und totalen Effekt (p=.001). Die vorliegenden längs-schnittlichen Daten bestätigen den Zusammenhang zwischen SMLF und SL bei einer Mediation über die EF und bestätigen somit die aus querschnittlichem Design stammenden Resultate von van der Niet et al. (2014). Literatur Best, J. R. (2010). Effects of physical activity on children’s executive function: Contributions of ex-perimental research on aerobic exercise. Developmental Review, 30, 331-351. Diamond, A. (2013). Executive functions. Annual Review of Psychology, 64, 135-168. van der Niet, A. G., Hartmann, E., Smith, J. & Visscher, C. (2014). Modeling relationships between physical fitness, executive functioning, and academic achievement in primary school chil-dren. Psychology of Sport & Exercise, 15(4), 319-325