Keep Rollin' - Whole-Body Motion Control and Planning for Wheeled Quadrupedal Robots

We show dynamic locomotion strategies for wheeled quadrupedal robots, which combine the advantages of both walking and driving. The developed optimization framework tightly integrates the additional degrees of freedom introduced by the wheels. Our approach relies on a zero-moment point based motion optimization which continuously updates reference trajectories. The reference motions are tracked by a hierarchical whole-body controller which computes optimal generalized accelerations and contact forces by solving a sequence of prioritized tasks including the nonholonomic rolling constraints. Our approach has been tested on ANYmal, a quadrupedal robot that is fully torque-controlled including the non-steerable wheels attached to its legs. We conducted experiments on flat and inclined terrains as well as over steps, whereby we show that integrating the wheels into the motion control and planning framework results in intuitive motion trajectories, which enable more robust and dynamic locomotion compared to other wheeled-legged robots. Moreover, with a speed of 4 m/s and a reduction of the cost of transport by 83 % we prove the superiority of wheeled-legged robots compared to their legged counterparts.Comment: IEEE Robotics and Automation Letter

The Effects of a New Bridge on Manatee (Trichechus manatus latirostris) Use of the FPL Discharge Canal at Port Everglades, Florida

The Florida manatee (Trichechus manatus latirostris) is an endangered species that migrates to warm water refuges such as natural springs or power plant effluents during the winter months to escape cold water. The Florida Power and Light (FPL) discharge canal in Port Everglades, Ft. Lauderdale, FL., is utilized as a refuge by overwintering manatees. Construction of a new bridge over the FPL effluent canal had a potential effect on manatee usage of the canal. Discharge is often 10-15° C warmer in the winter season than the surrounding waters of the Intracoastal Waterway. Previous data, including age class and cow/calf abundance from pre-bridge winters (2004-2009), were compared with data from winter 2010, during bridge construction and winter 2011, postbridge construction. No manatees were present at the survey sites during winter until surface water temperatures fell below 22° C. Although monthly mean surface water temperatures were not statistically different between 2008-2009, 2009-2010, and 2010-2011 (21.9±0.4° C, 21.8±1.8° C and 21.4±0.6° C respectively), manatee abundance did vary. 2008-2009 had higher monthly mean numbers of manatees per survey from December through March (29.7, 27.3, 48.1, 2 respectively) than 2009-2010 (0, 30, 10.7, 5 respectively) and 2010-2011 (18.7, 6.7, 0.1, 0 respectively). A Poisson distribution analysis showed a significant difference in adult manatee counts among the study years (α \u3c 0.05). No significant differences were found for juveniles and calves. While I cannot decisively state that bridge construction reduced the number of overwintering adult manatees during 2010, there appears to be the potential for an effect

Involucrin mRNA Is More Abundant in Human Hair Follicles Than in Normal Epidermis

Involucrin is a precursor protein of the cornified cell envelope in epidermal keratinocytes, where it has been located by immunohistochemistry in the upper spinous and granular layers of human epidermis. In the hair follicle, involucrin has been found in the inner root sheath and in the upper layers of the infundibulum and the isthmus (upper outer root sheath), whereas its presence in the lower outer root sheath and the cortex has been controversial. Therefore, we analyzed the distribution of involucrin mRNA in adult scalp by Northern blotting and in situ hybridization. Northern blots showed more abundant involucrin mRNA in the follicular fraction than in the epidermal fraction of dissected scalp. In situ hybridization matched the immunohistologic results; transcripts of involucrin were expressed not only in the infundibulum and isthmus, but also in the hair cortex and medulla, in all layers of the inner root sheath, and in the inner cells of the lower outer root sheath (all of which lack a cell envelope at the ultrastructural level). However, involucrin was absent in the hair cuticle, which is the only compartment of the follicle possessing a morphologically distinct cell envelope. Our results suggest, first, that involucrin does not serve as a precursor protein of the cornified cell envelope in adult hair follicles, and second, that it is perhaps not necessary for the formation of the cell envelope in keratinocytes of the hair cuticle, as we did not find this precursor protein with highly sensitive methodology

Unternehmenserbrecht – unde venis? Ein historischer Rückblick anlässlich der aktuellen Erbrechtsrevision

Im Rahmen der aktuellen Erbrechtsrevision wird im Schweizerischen Parlament die Einführung eines gesetzlichen Integralzuweisungsanspruchs zur Erhaltung von Unternehmen im Erbgang debattiert. Schon vor über 100 Jahren hatte sich EUGEN HUBER selbst an der Einführung eines solchen allgemeinen Unternehmenserbrechts versucht – und scheiterte knapp. Der historische Rückblick zeigt, dass sich schon damals dieselben Fragen stellten wie heute. Insbesondere die Frage, wie die Integralzuweisung von Unternehmen ermöglicht werden soll, ohne dabei zu stark in die Stellung der übrigen Erben einzugreifen, spaltete auch damals die Gemüter. Die historische Nachzeichnung der Debatte zeigt zum einen spannende Parallelen und Gegensätze zu den heutigen Streitpunkten in den Revisionsbemühungen auf. Zum anderen wird ein besonderes Augenmerk auf ein Rechtsinstitut gerichtet, das EUGEN HUBER damals als Kernstück seines Unternehmenserbrechts im Blick hatte: Die Gemeinderschaft (Art. 336-348 ZGB). Ob sie auch heute noch als Inspirationsquelle, Alternative oder Ergänzung dienen kann, dürfte nicht zuletzt vom Ausgang der Unternehmenserbrechtsrevision abhängen.Im Rahmen der aktuellen Erbrechtsrevision wird im Schweizerischen Parlament die Einführung eines gesetzlichen Integralzuweisungsanspruchs zur Erhaltung von Unternehmen im Erbgang debattiert. Schon vor über 100 Jahren hatte sich EUGEN HUBER selbst an der Einführung eines solchen allgemeinen Unternehmenserbrechts versucht – und scheiterte knapp. Der historische Rückblick zeigt, dass sich schon damals dieselben Fragen stellten wie heute. Insbesondere die Frage, wie die Integralzuweisung von Unternehmen ermöglicht werden soll, ohne dabei zu stark in die Stellung der übrigen Erben einzugreifen, spaltete auch damals die Gemüter. Die historische Nachzeichnung der Debatte zeigt zum einen spannende Parallelen und Gegensätze zu den heutigen Streitpunkten in den Revisionsbemühungen auf. Zum anderen wird ein besonderes Augenmerk auf ein Rechtsinstitut gerichtet, das EUGEN HUBER damals als Kernstück seines Unternehmenserbrechts im Blick hatte: Die Gemeinderschaft (Art. 336-348 ZGB). Ob sie auch heute noch als Inspirationsquelle, Alternative oder Ergänzung dienen kann, dürfte nicht zuletzt vom Ausgang der Unternehmenserbrechtsrevision abhängen

Quasi-Normal Cornified Cell Envelopes in Loricrin Knockout Mice Imply the Existence of a Loricrin Backup System

The cornified cell envelope, a lipoprotein layer that assembles at the surface of terminally differentiated keratinocytes, is a resilient structure on account of covalent crosslinking of its constituent proteins, principally loricrin, which accounts for up to 60%-80% of total protein. Despite the importance of the cell envelope as a protective barrier, knocking out the loricrin gene in mice results in only mild syndromes. We have investigated the epidermis and forestomach epithelium of these mice by electron microscopy. In both tissues, corneocytes have normal-looking cell envelopes, despite the absence of loricrin, which was confirmed by immunolabeling, and the absence of the distinctive loricrin-containing keratohyalin granules (L-granules). Isolated cell envelopes were normal in thickness (≈15 nm) and mass per unit area (≈7.3 kDa per nm2); however, metal shadowing revealed an altered substructure on their cytoplasmic surface. Their amino acid compositions indicate altered protein compositions. Analysis of these data implies that the epidermal cell envelopes have elevated levels of the small proline-rich proteins, and cell envelopes of both kinds contain other protein(s) that, like loricrin, are rich in glycine and serine. These observations imply that, in the absence of loricrin, the mechanisms that govern cell envelope assembly function normally but employ different building-blocks