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Université de Fribourg

Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria

Ezcurra, Martín D. ; Nesbitt, Sterling J. ; Bronzati, Mario ; Vecchia, Fabio Marco Dalla ; Agnolin, Federico L. ; Benson, Roger B. J. ; Egli, Federico Brissón ; Cabreira, Sergio F. ; Evers, Serjoscha W. ; Gentil, Adriel R. ; Irmis, Randall B. ; Martinelli, Agustín G. ; Novas, Fernando E. ; Silva, Lúcio Roberto da ; Smith, Nathan D. ; Stocker, Michelle R. ; Turner, Alan H. ; Langer, Max C.

In: Nature, 2020, vol. 588, no. 2020-7838, p. 445–449

Pterosaurs were the first vertebrates to evolve powered flight1 and comprised one of the main evolutionary radiations in terrestrial ecosystems of the Mesozoic era (approximately 252–66 million years ago), but their origin has remained an unresolved enigma in palaeontology since the nineteenth century2,3,4. These flying reptiles have been hypothesized to be the close relatives of a wide...

Université de Fribourg

Simple assessment of height and length of flight in complex gymnastic skills: validity and reliability of a two-dimensional video analysis method

Schärer, Christoph ; Siebenthal, Luca von ; Lomax, Ishbel ; Gross, Micah ; Taube, Wolfgang ; Hübner, Klaus

In: Applied Sciences, 2019, vol. 9, no. 19, p. 3975

In artistic gymnastics, the possibility of using 2D video analysis to measure the peak height (hpeak) and length of flight (L) during routine training in order to monitor the execution and development of difficult elements is intriguing. However, the validity and reliability of such measurements remain unclear. Therefore, in this study, the hpeak and L of 38 vaults, performed by top-level...

Università della Svizzera italiana

Optimization of anchor nodes placement in wireless localization networks

Balac, Katarina ; Malek, Miroslaw (Dir.) ; Prevostini, Mauro (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2019 ; 2019INFO009.

This work focuses on optimizing node placement for time-of-flight-based wireless localization networks. Main motivation are critical safety applications. The first part of my thesis is an experimental study on in-tunnel vehicle localization. In- tunnel localization of vehicles is crucial for emergency management, especially for large trucks transporting dangerous goods such as inflammable...

Université de Fribourg

The faster, the better? Relationships between run-up speed, the degree of difficulty (D-score), height and length of flight on vault in artistic gymnastics

Schärer, Christoph ; Lehmann, Thomas ; Naundorf, Falk ; Taube, Wolfgang ; Hübner, Klaus

In: PLOS ONE, 2019, vol. 14, no. 3, p. e0213310

On vault in artistic gymnastics, a high run-up speed is thought to be important when performing difficult vaults. To test this assumption in a large cohort of elite athletes, we calculated the correlations between the run-up speed, scores, height and length of flight for handspring-, Tsukahara- and Yurchenko-style vaults and compared the performances of male and female elite and junior...

Université de Fribourg

A note on the Petersen-Wilhelm conjecture

González-Álvaro, David ; Radeschi, Marco

In: Proceedings of the American Mathematical Society, 2018, vol. 146, no. 10, p. 4447–4458

In this note we consider submersions from compact manifolds, homotopy equivalent to the Eschenburg or Bazaikin spaces of positive curvature. We show that if the submersion is nontrivial, the dimension of the base is greater than the dimension of the fiber. Together with previous results, this proves the Petersen-Wilhelm conjecture for all the known compact manifolds with positive curvature.