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Gripping and holding of objects are key tasks for robotic manipulators. The development of universal grippers able to pick up unfamiliar objects of widely varying shape and surface properties remains, however, challenging. Most current designs are based on the multifingered hand, but this approach introduces hardware and software complexities. These include(More)
We describe three apparatus, known as the large, medium, and small apparatus, used for high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for cylindrical samples of fluid and present results illustrating the influence of the finite conductivity of the top and bottom plates on the heat transport in the fluid. We used(More)
OBJECTIVE To test whether the Communities That Care (CTC) prevention system reduces adolescent alcohol, tobacco, and other drug use and delinquent behavior communitywide. DESIGN The Community Youth Development Study is the first randomized trial of CTC. SETTING In 2003, 24 small towns in 7 states, matched within state, were randomly assigned to control(More)
We describe a simple passive universal gripper, consisting of a mass of granular material encased in an elastic membrane. Using a combination of positive and negative pressure, the gripper can rapidly grip and release a wide range of objects that are typically challenging for universal grippers, such as flat objects, soft objects, or objects with complex(More)
Raising Healthy Children (RHC) is a preventive intervention designed to promote positive youth development by targeting developmentally appropriate risk and protective factors. In this study, the authors tested the efficacy of the RHC intervention on reducing adolescent alcohol, marijuana, and cigarette use. Ten public schools, which comprised 959 1st- and(More)
We present measurements of the orientation theta0(t) of the large-scale circulation (LSC) of turbulent Rayleigh-Bénard convection in cylindrical cells of aspect ratio 1. Theta0(t) undergoes irregular reorientations. It contains reorientation events by rotation through angles delta theta with a monotonically decreasing probability distribution p(delta(More)
Non-Oberbeck–Boussinesq (NOB) effects on the Nusselt number Nu and Reynolds number Re in strongly turbulent Rayleigh–Bénard (RB) convection in liquids were investigated both experimentally and theoretically. In the experiments the heat current, the temperature difference, and the temperature at the horizontal midplane were measured. Three cells of different(More)
We present high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for cylindrical samples of water (Prandtl number σ = 4.4) with a diameter D of 49.7 cm and heights L = 116.3, 74.6, and 50.6 cm, as well as for D = 24.8 cm and L = 90.2 cm. For each aspect ratio Γ ≡ D/L = 0.28, 0.43, 0.67, and 0.98 the data cover a range of(More)
PURPOSE Communities That Care (CTC) is a prevention system designed to reduce levels of adolescent delinquency and substance use through the selection and use of effective preventive interventions tailored to a community's specific profile of risk and protection. This article describes early findings from the first group-randomized trial of CTC. METHODS A(More)
Communities That Care (CTC) is a prevention system designed to reduce adolescent substance use and delinquency through the selection of effective preventive interventions tailored to a community's specific profile of risk and protection. A community-randomized trial of CTC, the Community Youth Development Study, is currently being conducted in 24(More)