Desert RHex Technical Report: Tengger Desert Trip

Desertification is a long-standing issue in China, but research on the processes of desertification is limited by availability of personnel and technical equipment. This suggests a perfect application and further testing ground for the mobile desert sensing technology described in a previous technical report. We describe here the first of two trips to the Tengger Desert as part of a collaborative effort to bring Desert RHexes to China, with the goal of this trip being to discover and address potential locomotor challenges. Our robots were able to ascend 20-degree slopes with an 8.5kg payload, indicating that they could indeed be used for this novel mobile desert sensor application. We achieved locomotion on up to 30-degree slopes unreliably and on up to 27-degree slopes using morphological and behavioral adaptations inspired by our last desert trip

Free-Standing Leaping Experiments with a Power-Autonomous, Elastic-Spined Quadruped

We document initial experiments with Canid, a freestanding, power-autonomous quadrupedal robot equipped with a parallel actuated elastic spine. Research into robotic bounding and galloping platforms holds scientific and engineering interest because it can both probe biological hypotheses regarding bounding and galloping mammals and also provide the engineering community with a new class of agile, efficient and rapidly-locomoting legged robots. We detail the design features of Canid that promote our goals of agile operation in a relatively cheap, conventionally prototyped, commercial off-the-shelf actuated platform. We introduce new measurement methodology aimed at capturing our robot’s “body energy” during real time operation as a means of quantifying its potential for agile behavior. Finally, we present joint motor, inertial and motion capture data taken from Canid’s initial leaps into highly energetic regimes exhibiting large accelerations that illustrate the use of this measure and suggest its future potential as a platform for developing efficient, stable, hence useful bounding gaits. For more information: Kod*La

The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases

The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article

Formal design of a provably safe robotic roundabout system

In this paper, we show how to design a provably safe robotic roundabout system comprised of three vehicles. This is accomplished by combining two-vehicle collision avoidance primitives, which are each computationally light given the natural partial order structure on which the system evolves. We show how to design the system parameters in order to prevent conflicts among the control primitives, and to thus ensure the safety and liveness of the system as a whole. We implement our design on a multi-vehicle test-bed involving three vehicles continuously running on three intersecting roundabouts, and provide experimental results demonstrating the system is collision free and live.National Science Foundation (U.S.) (NSF-CAREER Award CNS-0642719)National Science Foundation (U.S.) (NSF-GOALI Award CMMI-0854907

Distance from Sub-Saharan Africa Predicts Mutational Load in Diverse Human Genomes

The Out-of-Africa (OOA) dispersal ∼50,000 y ago is characterized by a series of founder events as modern humans expanded into multiple continents. Population genetics theory predicts an increase of mutational load in populations undergoing serial founder effects during range expansions. To test this hypothesis, we have sequenced full genomes and high-coverage exomes from seven geographically divergent human populations from Namibia, Congo, Algeria, Pakistan, Cambodia, Siberia, and Mexico. We find that individual genomes vary modestly in the overall number of predicted deleterious alleles. We show via spatially explicit simulations that the observed distribution of deleterious allele frequencies is consistent with the OOA dispersal, particularly under a model where deleterious mutations are recessive. We conclude that there is a strong signal of purifying selection at conserved genomic positions within Africa, but that many predicted deleterious mutations have evolved as if they were neutral during the expansion out of Africa. Under a model where selection is inversely related to dominance, we show that OOA populations are likely to have a higher mutation load due to increased allele frequencies of nearly neutral variants that are recessive or partially recessive