3,100 research outputs found

    "Muscled Presence": Douglas Livingstone's poem "Thirteen Ways of Looking at a Black Snake"

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    Douglas Livingstone's poem "Thirteen Ways of Looking at a Black Snake" is an artwork which addresses precisely these questions, seeking a manner of portraying the snake which is neither grossly appropriative nor wholly detached, neither ethically empty nor preachy. In its multi-angled structure, Livingstone attempts aesthetically "to establish and embellish ... a contact zone with the nonhuman animals who share our world with us, but accepting also that there exist considerable venues on either side of this contact zone that are, on the one hand, only human, and on the other hand, only nonhuman". Even in his more formally scientific work, Livingstone argues for the inevitability of such limits to knowledge, and for the value of the imagination in addressing them

    Signatures of the collapse and revival of a spin Schr\"{o}dinger cat state in a continuously monitored field mode

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    We study the effects of continuous measurement of the field mode during the collapse and revival of spin Schr\"{o}dinger cat states in the Tavis-Cummings model of N qubits (two-level quantum systems) coupled to a field mode. We show that a compromise between relatively weak and relatively strong continuous measurement will not completely destroy the collapse and revival dynamics while still providing enough signal-to-noise resolution to identify the signatures of the process in the measurement record. This type of measurement would in principle allow the verification of the occurrence of the collapse and revival of a spin Schr\"{o}dinger cat state.Comment: 5 pages, 2 figure

    Nonlinear backreaction in a quantum mechanical SQUID

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    In this paper we discuss the coupling between a quantum mechanical superconducting quantum interference device (SQUID) and an applied static magnetic field. We demonstrate that the backreaction of a SQUID on the applied field can interfere with the ability to bias the SQUID at values of the static (DC) magnetic flux at, or near to, transitions in the quantum mechanical SQUID.Comment: 9 pages, to be published in Phys. Rev.

    Leaf reflectance-nitrogen-chlorophyll relations among three south Texas woody rangeland plant species

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    Annual variations in the nitrogen-chlorophyll leaf reflectance of hackberry, honey mesquite and live oak in south Texas, were compared. In spring, leaf reflectance at the 0.55 m wavelength and nitrogen (N) concentration was high but leaf chlorophyll (chl) concentrations were low. In summer, leaf reflectance and N-concentration were low but lead chl concentrations were high. Linear correlations for both spring and summer of leaf reflectance with N and chl concentration or deviations from linear regression were not statistically significant

    Guidance and Control in a Josephson Charge Qubit

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    In this paper we propose a control strategy based on a classical guidance law and consider its use for an example system: a Josephson charge qubit. We demonstrate how the guidance law can be used to attain a desired qubit state using the standard qubit control fields.Comment: 9 pages, 5 figure

    To perform a gyro test of general relativity in a satellite and develop associated control technology

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    Performance tests of gyroscope operations and gyroscope readout equipment are discussed. The gyroscope was tested for 400 hours at liquid helium temperatures with spin speeds up to 30 Hz. Readout by observing trapped magnetic flux in the spinning rotor with a sensitive magnetometer was accomplished. Application of the gyroscope to space probes and shuttle vehicles

    Sexual Behavior of Bowhead Whales Observed Off the North Coast of Alaska

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    ... on 8 May 1976 approximately 32 km east of Point Barrow ... we observed and photographed a group of six bowhead whales engaged in sexual behavior in an open water "lead" in the pack ice. ... A series of 15, 35 mm photographs taken with a motor drive attachment provided a clear record of the observation. ... The aspect of each whale will be described as dorsal, lateral, or ventral, depending on which surface of the whale was toward the observer. ..

    How RL Agents Behave When Their Actions Are Modified

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    Reinforcement learning in complex environments may require supervision to prevent the agent from attempting dangerous actions. As a result of supervisor intervention, the executed action may differ from the action specified by the policy. How does this affect learning? We present the Modified-Action Markov Decision Process, an extension of the MDP model that allows actions to differ from the policy. We analyze the asymptotic behaviours of common reinforcement learning algorithms in this setting and show that they adapt in different ways: some completely ignore modifications while others go to various lengths in trying to avoid action modifications that decrease reward. By choosing the right algorithm, developers can prevent their agents from learning to circumvent interruptions or constraints, and better control agent responses to other kinds of action modification, like self-damage.Comment: 10 pages (+6 appendix); 7 figures. Published in the AAAI 2021 Conference on AI. Code is available at https://github.com/edlanglois/mamd
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