4,809 research outputs found

    A very low frequency radio astronomy observatory on the Moon

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    Because of terrestrial ionospheric absorption, very little is known of the radio sky beyond 10 m wavelength. An extremely simple, low cost very low frequency radio telescope is proposed, consisting of a large array of short wires laid on the lunar surface, each wire equipped with an amplifier and a digitizer, and connected to a common computer. The telescope could do simultaneous multifrequency observations of much of the visible sky with high resolution in the 10 to 100 m wavelength range, and with lower resolution in the 100 to 1000 m range. It would explore structure and spectra of galactic and extragalactic point sources, objects, and clouds, and would produce detailed quasi-three-dimensional mapping of interstellar matter within several thousand parsecs of the Sun

    Quantum imaging of spin states in optical lattices

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    We investigate imaging of the spatial spin distribution of atoms in optical lattices using non-resonant light scattering. We demonstrate how scattering spatially correlated light from the atoms can result in spin state images with enhanced spatial resolution. Furthermore, we show how using spatially correlated light can lead to direct measurement of the spatial correlations of the atomic spin distribution

    Heat and Mass Transfer in Cold Regions Soils

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    The work upon which this report is based was made possible by a cooperative aid agreement between the U.S. Forest Service, Institute of Northern Forestry, Fairbanks, Alaska, and the Institute of Water Resources, University of Alaska. Contributions to this study were also made by the University of California at Davis and Ohio State University. The collection of winter data on pore pressures was made possible by a separate grant by the Office of Water Research and Technology (project A-053 ALAS)

    An Approach to Ecosystem-Based Fishery Management

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    Marine scientists and policymakers are encouraging ecosystem-based fishery management (EBFM), but there is limited guidance on how to operationalize the concept. We adapt financial portfolio theory as a method for EBFM that accounts for species interdependencies, uncertainty, and sustainability constraints. Illustrating our method with routinely collected data available from the Chesapeake Bay, we demonstrate the gains from taking into account species variances and covariances in setting species total allowable catches. We find over the period from 1962–2003 that managers could have increased the revenues from fishing and reduced the variance by employing ecosystem frontiers in setting catch levels.ecosystem-based fishery management, portfolio, trophic modeling, precaution

    On the Survivability and Metamorphism of Tidally Disrupted Giant Planets: the Role of Dense Cores

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    A large population of planetary candidates in short-period orbits have been found through transit searches. Radial velocity surveys have also revealed several Jupiter-mass planets with highly eccentric orbits. Measurements of the Rossiter-McLaughlin effect indicate some misaligned planetary systems. This diversity could be induced by post-formation dynamical processes such as planet-planet scattering, the Kozai effect, or secular chaos which brings planets to the vicinity of their host stars. In this work, we propose a novel mechanism to form close-in super-Earths and Neptune-like planets through the tidal disruption of giant planets as a consequence of these dynamical processes. We model the core-envelope structure of giant planets with composite polytropes. Using three-dimensional hydrodynamical simulations of close encounters between planets and their host stars, we find that the presence of a core with a mass more than ten Earth masses can significantly increase the fraction of envelope which remains bound to it. After the encounter, planets with cores are more likely to be retained by their host stars in contrast with previous studies which suggested that coreless planets are often ejected. As a substantial fraction of their gaseous envelopes is preferentially lost while the dense incompressible cores retain most of their original mass, the resulting metallicity of the surviving planets is increased. Our results suggest that some gas giant planets can be effectively transformed into either super-Earths or Neptune-like planets after multiple close stellar passages. Finally, we analyze the orbits and structure of known planets and Kepler candidates and find that our model is capable producing some of the shortest-period objects.Comment: Accepted for publication in ApJ. 15 pages, 9 figures, 3 tables. Two movies at http://youtu.be/jHxPKAEgFic and http://youtu.be/QXqkS0vDi5

    Improving Lawyers’ Judgment: Is Mediation Training De-Biasing?

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    When people are placed in a partisan role or otherwise have an objective they seek to accomplish, they are prone to pervasive cognitive and motivational biases. These judgmental distortions can affect what people believe and wish to find out, the predictions they make, the strategic decisions they employ, and what they think is fair. A classic example is confirmation bias, which can cause its victims to seek and interpret information in ways that are consistent with their pre-existing views or the goals they aim to achieve. Studies consistently show that experts as well as laypeople are prone to such biases, and that they are highly resistant to change, in large part because people are generally unaware that they are operating. When they affect lawyers, egocentric, partisan and role biases can hinder the ability to provide objective advice to clients, lead to overly optimistic forecasts about the probability of future events, and promote “we-they” thinking that can exacerbate and prolong conflicts, imposing substantial costs on both clients and society. There is reason to believe that by placing people in a mediative stance—one in which people impartially try to help disputants resolve a conflict—they can develop habits of objectivity crucial to much of what lawyers are called upon to do. That this is so is supported by social science research on two specific strategies for de-biasing judgment—considering alternative scenarios and taking another’s perspective—both core mediator mindsets. Research also shows that active engagement in such de-biasing activity is more effective in achieving objectivity than is mere instruction about the existence of cognitive biases. The authors consider the implications of this research for law school clinical programming and legal education in general

    Planar waveguide biosensors for nucleic acid hybridization reactions

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    Journal ArticleOligonucleotide probes derived from (1) the T3 RNA polymerase promoter sequence (T3) and (2) prostate-specific antigen messenger RNA (PSA) were prepared and labeled with a red-emitting fluorescent dye (Cy5). The complimentary oligonucleotides (anti T3 and anti PSA) were prepared and labeled with biotin. Initially, a feasibility study was performed in which the hybridization rate of the T3/anti T3 oligonucleotide pair was examined. Specifically, biotinylated anti T3 was immobilized to a neutravidin-coated waveguide and solutions containing increasing concentrations of Cy5-labeled T3 were injected into the biosensor. Fluorescence emission was detected with an evanescent wave imaging fluorometer. The hybridization reaction proceeded rapidly with a significant amount of binding occurring during the first 5 minutes. A Michaelis-Menton kinetics model was used to analyze hybridization rate data and gave values of 78 nanomolar for the apparent affinity of the hybridization reaction and 1.4 picomolar for the analytical sensitivity of the hybridization assay. In subsequent studies the hybridization rate of the PSA/anti PSA oligonucleotide pair was examined. Biotinylated anti PSA was immobilized to the waveguide and solutions containing increasing concentrations of Cy5-labeled PSA were injected into the biosensor. The hybridization rate observed for formation of the PSA/anti PSA pair was comparable to the high rates observed for the T3/anti T3 pair. Lastly, the selectivity of the biosensor was examined using an oligonucleotide probe derived from human glandular kallikrein (hGK), which exhibits a high degree of homology to PSA. The two oligonucleotide probes (PSA and hGK) only differed in 7 out of 20 positions. Interestingly, the hybridization rate observed for Cy5-Iabeled hGK was very low-not statistically different from the non-specific binding rate of the hybridization assay

    Changing Minds: The Work of Mediators and Empirical Studies of Persuasion

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    The use of mediation has grown exponentially in recent years in courts, agencies, and community settings. Yet the field of mediation still operates to a considerable extent on folklore and opinion, rather than reliable knowledge. Mediator attempts at persuasion are pervasive in a wide variety of mediation contexts, yet “persuasion” is, for some, a pejorative word and a contested norm in the field. Perhaps as a result, there has been little, if any, evidence-based writing about what kinds of persuasive appeals might be effective in mediation, how they might operate, and how they might be experienced by disputants. In an effort to begin to fill that void, this article examines empirical research findings on persuasion from such diverse fields as advertising, public health, communications, politics and race relations. It focuses on studies of both indirect or behavioral approaches to persuasion (role reversal, apology, group brainstorming) and different types of direct persuasive appeals (questions vs. statements, more vs. less explicit statements, use of “negative” emotions such as fear and guilt, and sequential vs. straightforward requests for concessions). As almost none of the empirical work on persuasion has involved dispute resolution, the article raises questions about how these social science findings might apply to the work of mediators. Some of the research findings described in this article are unsurprising, while others may challenge common assumptions. Where the research appears at odds with conventional mediation wisdom, the authors discuss its potential implications for ongoing philosophical and skills-based debates in the field. Of particular note, the literature canvassed in this article may cast new light on old debates about facilitative versus evaluative mediation, and the importance of mediators having substantive, as well as process, expertise

    Can we avoid dark energy?

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    The idea that we live near the centre of a large, nonlinear void has attracted attention recently as an alternative to dark energy or modified gravity. We show that an appropriate void profile can fit both the latest cosmic microwave background and supernova data. However, this requires either a fine-tuned primordial spectrum or a Hubble rate so low as to rule these models out. We also show that measurements of the radial baryon acoustic scale can provide very strong constraints. Our results present a serious challenge to void models of acceleration.Comment: 5 pages, 4 figures; minor changes; version published in Phys. Rev. Let
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