1,614 research outputs found

    Axel: A Minimalist Tethered Rover for Exploration of Extreme Planetary Terrains

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    Recent scientific findings suggest that some of the most interesting sites for future exploration of planetary surfaces lie in terrains that are currently inaccessible to conventional robotic rovers. To provide robust and flexible access to these terrains, we have been developing Axel, the robotic rover. Axel is a lightweight two-wheeled vehicle that can access steep terrains and negotiate relatively large obstacles because of its actively managed tether and novel wheel design. This article reviews the Axel system and focuses on those system components that affect Axel's steep terrain mobility. Experimental demonstrations of Axel on sloped and rocky terrains are presented

    Simulation of the White Dwarf -- White Dwarf galactic background in the LISA data

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    LISA (Laser Interferometer Space Antenna) is a proposed space mission, which will use coherent laser beams exchanged between three remote spacecraft to detect and study low-frequency cosmic gravitational radiation. In the low-part of its frequency band, the LISA strain sensitivity will be dominated by the incoherent superposition of hundreds of millions of gravitational wave signals radiated by inspiraling white-dwarf binaries present in our own galaxy. In order to estimate the magnitude of the LISA response to this background, we have simulated a synthesized population that recently appeared in the literature. We find the amplitude of the galactic white-dwarf binary background in the LISA data to be modulated in time, reaching a minimum equal to about twice that of the LISA noise for a period of about two months around the time when the Sun-LISA direction is roughly oriented towards the Autumn equinox. Since the galactic white-dwarfs background will be observed by LISA not as a stationary but rather as a cyclostationary random process with a period of one year, we summarize the theory of cyclostationary random processes and present the corresponding generalized spectral method needed to characterize such process. We find that, by measuring the generalized spectral components of the white-dwarf background, LISA will be able to infer properties of the distribution of the white-dwarfs binary systems present in our Galaxy.Comment: 14 pages and 6 figures. Submitted to Classical and Quantum Gravity (Proceedings of GWDAW9

    Pluripolarity of Graphs of Denjoy Quasianalytic Functions of Several Variables

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    In this paper we prove pluripolarity of graphs of Denjoy quasianalytic functions of several variables on the spanning se

    Perceptions and understanding of research situations as a function of consent form characteristics and experimenter instructions

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    Two studies examined how research methodology affected participant behaviors. Study 1 tested (a) consent form perspective (1st, 2nd, or 3rd person) and (b) information on participants’ right to sue upon perceptions of coercion, ability to recall consent information, and performance on experimental tasks. Unexpectedly, participants who received instructions without the right to sue information had significantly better recall of their research rights. Study 2 manipulated (a) consent form complexity (presence or absence of jargon) and (b) the detail of verbal instructions (simple, elaborate); participants who received a consent form with simpler language spent more time on a difficult task, and participants in the elaborate instruction condition recalled more details. Together, these studies suggest (a) explaining the right to sue may actually be counterproductive; (b) providing a more detailed explanation may help participants remember procedural details; and (c) using jargon may decrease task performance

    Sex Differences in Jealousy in Response to Actual Infidelity

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    The present studies address two criticisms of the theory of evolved sex differences in jealousy: (a) that the sex difference in jealousy emerges only in response to hypothetical infidelity scenarios, and (b) that the sex difference emerges only using forced-choice measures. In two separate studies, one a paper-and-pencil survey with a student sample and the other a web-based survey targeting a non-student sample, men and women showed significant sex differences in jealousy in response to actual infidelity experiences; men experienced more jealousy in response to the sexual aspects of an actual infidelity, whereas women experienced more jealousy in response to the emotional aspects of the infidelity. Sex differences emerged using both continuous measures of jealousy as well as the traditional forced-choice measure. Overall, our results demonstrate that sex differences in jealousy are not limited to responses to hypothetical infidelity scenarios; they also emerge in response to actual infidelity experiences

    Robotic Two-Wheeled Vehicle

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    A robotic two-wheeled vehicle comprising a connection body interposed between the two wheels are described. A drum can be coaxially located in a central region of the connection body and can support a hollow arm projecting radially from the drum. A tether can be inserted in the arm and connected to a second drum. Instruments and sensors can be accommodated in a case housed inside each wheel

    Searching for Gravitational Waves with a Geostationary Interferometer

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    We analyze the sensitivities of a geostationary gravitational wave interferometer mission operating in the sub-Hertz band. Because of its smaller armlength, in the lower part of its accessible frequency band (10−4−2×10−210^{-4} - 2 \times 10^{-2} Hz) our proposed Earth-orbiting detector will be less sensitive, by a factor of about seventy, than the Laser Interferometer Space Antenna (LISA) mission. In the higher part of its band instead (2×10−2−102 \times 10^{-2} - 10 Hz), our proposed interferometer will have the capability of observing super-massive black holes (SMBHs) with masses smaller than ∼106\sim 10^{6} M⊙_{\odot}. With good event rates for these systems, a geostationary interferometer will be able to accurately probe the astrophysical scenarios that account for their formation.Comment: 33 pages, 9 eps figure
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