A Bio-Inspired Tensegrity Manipulator with Multi-DOF, Structurally Compliant Joints

Most traditional robotic mechanisms feature inelastic joints that are unable to robustly handle large deformations and off-axis moments. As a result, the applied loads are transferred rigidly throughout the entire structure. The disadvantage of this approach is that the exerted leverage is magnified at each subsequent joint possibly damaging the mechanism. In this paper, we present two lightweight, elastic, bio-inspired tensegrity robotics arms which mitigate this danger while improving their mechanism's functionality. Our solutions feature modular tensegrity structures that function similarly to the human elbow and the human shoulder when connected. Like their biological counterparts, the proposed robotic joints are flexible and comply with unanticipated forces. Both proposed structures have multiple passive degrees of freedom and four active degrees of freedom (two from the shoulder and two from the elbow). The structural advantages demonstrated by the joints in these manipulators illustrate a solution to the fundamental issue of elegantly handling off-axis compliance.Comment: IROS 201

Ecological and Economic Implications of a Tropical Jellyfish Invader In the Gulf of Mexico

A large population of a previously unreported jellyfish occurred across the northern Gulf of Mexico (USA) from May through September of 2000. The jellyfish, identified as Phyllorhiza punctata by von Lendenfeld (1884), is not indigenous to the Gulf of Mexico or to the Atlantic Basin. Current theory states that this invasive species was introduced into the Atlantic from the Pacific Ocean through the Panama Canal about 45 years ago, and several confirmed reports indicated that a cryptic population may have existed in the northern Gulf since 1993. However, mesoscale hydrographic anomalies in spring 2000 may have directly transported the population from the Caribbean Sea where populations of P. punctata have been reported previously in Puerto Rico. We undertook a rapid-response sampling program from June through September to obtain ecological information regarding P. punctata in the highly productive northern Gulf waters. Jellyfish bell diameter increased by about 50% (from an average of 32 ±12 to 45 ± 6 cm) as animals invaded nearshore waters during July. As the summer progressed, a net westerly distribution shift followed nearshore currents to an accumulation point near the mouth of Lake Borgne, Louisiana, in the far western Mississippi Sound. In the Lake Borgne aggregation, we estimated 5.37 × 106 medusae over an area of about 150 km2. All of the medusae appeared to lack the symbiotic algae that are present in all other described populations, and therefore must have depended solely on planktivory for their nutrition. Clearance rates estimated from ambient zooplankton, gut contents and published digestion times ranged from \u3c1 m3 d−1 for adult copepods to over 90 m3 d−1 for fish eggs. Based on these clearance rates, the central core of this aggregation (30 km2) was being turned over at least once per day with even higher turn-over in very concentrated’ super-swarms’. Clogging of shrimp nets was the greatest economic impact,and perhaps contributed to millions of dollars in economic losses. The indirect effect of predation on eggs and larvae of commercially important finfish and shellfish remained intangible in the determination of economic effects. In 2001, P. punctata has recurred along southern Louisiana and has apparently spread into the coastal and lagoonal waters of the Florida east coast

A genomewide scan for early-onset coronary artery disease in 438 families: the GENECARD Study.

A family history of coronary artery disease (CAD), especially when the disease occurs at a young age, is a potent risk factor for CAD. DNA collection in families in which two or more siblings are affected at an early age allows identification of genetic factors for CAD by linkage analysis. We performed a genomewide scan in 1,168 individuals from 438 families, including 493 affected sibling pairs with documented onset of CAD before 51 years of age in men and before 56 years of age in women. We prospectively defined three phenotypic subsets of families: (1) acute coronary syndrome in two or more siblings; (2) absence of type 2 diabetes in all affected siblings; and (3) atherogenic dyslipidemia in any one sibling. Genotypes were analyzed for 395 microsatellite markers. Regions were defined as providing evidence for linkage if they provided parametric two-point LOD scores >1.5, together with nonparametric multipoint LOD scores >1.0. Regions on chromosomes 3q13 (multipoint LOD = 3.3; empirical P valu