4,049 research outputs found

    A qq-Queens Problem. II. The Square Board

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    We apply to the n×nn\times n chessboard the counting theory from Part I for nonattacking placements of chess pieces with unbounded straight-line moves, such as the queen. Part I showed that the number of ways to place qq identical nonattacking pieces is given by a quasipolynomial function of nn of degree 2q2q, whose coefficients are (essentially) polynomials in qq that depend cyclically on nn. Here we study the periods of the quasipolynomial and its coefficients, which are bounded by functions, not well understood, of the piece's move directions, and we develop exact formulas for the very highest coefficients. The coefficients of the three highest powers of nn do not vary with nn. On the other hand, we present simple pieces for which the fourth coefficient varies periodically. We develop detailed properties of counting quasipolynomials that will be applied in sequels to partial queens, whose moves are subsets of those of the queen, and the nightrider, whose moves are extended knight's moves. We conclude with the first, though strange, formula for the classical nn-Queens Problem and with several conjectures and open problems.Comment: 23 pp., 1 figure, submitted. This = second half of 1303.1879v1 with great improvements. V2 has a new proposition, better definitions, and corrected conjectures. V3 has results et al. renumbered to correspond with published version, and expands dictionary's cryptic abbreviation

    NiO Exchange Bias Layers Grown by Direct Ion Beam Sputtering of a Nickel Oxide Target

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    A new process for fabricating NiO exchange bias layers has been developed. The process involves the direct ion beam sputtering (IBS) of a NiO target. The process is simpler than other deposition techniques for producing NiO buffer layers, and facilitates the deposition of an entire spin-valve layered structure using IBS without breaking vacuum. The layer thickness and temperature dependence of the exchange field for NiO/NiFe films produced using IBS are presented and are similar to those reported for similar films deposited using reactive magnetron sputtering. The magnetic properties of highly textured exchange couples deposited on single crystal substrates are compared to those of simultaneously deposited polycrystalline films, and both show comparable exchange fields. These results are compared to current theories describing the exchange coupling at the NiO/NiFe interface.Comment: 9 pages, Latex 2.09, 3 postscript figures. You can also this manuscript at http://www.wsrcc.com/alison/fixed-nio/manuscript.html To be published in _IEEE Trans. Magn._, Nov. 199

    Communicating health decisions: an analysis of messages posted to online prostate cancer forums

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    Background  Experiential websites such as message forums and blogs allow Prostate Cancer (PCa) patients to communicate their health decisions to peers. The issues surrounding this form of indirect involvement in public health are little understood. Objective  This paper explores the types of decision-making processes that people are exposed to on PCa online message boards. The kinds of treatment choices patients are making and the reports of their decision-making processes to peers through an online environment are examined in the context of the Heuristic Systematic Model. Method  Messages about treatment decision making were collected from four PCa websites. In total, 137 messages were selected from blogs and online forums and their decision-making processes coded. Results  Men looking online for information about treatment options for PCa are exposed to a range of decision-making processes. Just under half (49.6%) of the messages reported non-systematic decision processes, with deferral to the doctor and proof of cancer removal being the most common. For systematic processing (36.5%), messages most commonly considered treatment outcomes and side-effects. Processes did not vary between the blogs and online forums. Discussion and conclusion  Compared to previous studies far fewer messages reported non-systematic decision processes and only a small number of messages reflected lay beliefs or misbeliefs about PCa treatment. Implications for men and their clinicians of seeking health information online are discussed

    Prototypicality of arguments and conformity to ingroup norms

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    Social categorization is claimed to elicit a tendency to conform to ingroup norms, which may result in attitude change after exposure to information on the opinions of other ingroup members. It was hypothesized that the degree to which arguments represented ingroup norms, i.e., were prototypical, would affect their potential influence on attitudes, such that prototypical arguments would be perceived as being of higher quality and would elicit more attitude change. Moreover, prototypical arguments were expected to elicit more argument elaboration. Two experiments were designed to test these predictions. In Experiment 1 subjects were exposed to both a set of pro and a set of contra arguments, while one of the sets was allegedly prototypical of ingroup attitudes. In Experiment 2 subjects were exposed to either prototypical or a-prototypical pro or contra arguments allegedly originating from in- or outgroup. In both studies conformity to ingroup norms was observed. In addition, prototypical ingroup arguments elicited higher quality ratings in the first study. Indications of higher elaboration of prototypical ingroup arguments were found

    X-ray Absorption Study of Pulsed Laser Deposited Boron Nitride Films

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    B and N K-edge x-ray absorption spectroscopy measurements have been performed on three BN thin films grown on Si substrates using ion-assisted pulsed laser deposition. Comparison of the films' spectra to those of several single-phase BN powder standards shows that the films consist primarily of sp2sp^2 bonds. Other features in the films' spectra suggest the presence of secondary phases, possibly cubic or rhombohedral BN. Films grown at higher deposition rates and higher ion-beam voltages are found to be more disordered, in agreement with previous work.Comment: 7 pages, LaTeX 2.09. Figures not included, but available by fax. Send email to [email protected]

    Update on Radiation Testing for Space Fission Power Systems

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    Radiation effects on materials and electronics is a major topic that needs to be addressed for a nuclear reactor flight demonstration of the Kilopower reactor. The Kilopower project team has taken steps towards developing a standardized radiation environment qualification program for components and materials. Candidate nuclear reactor facilities for both low fluence electronics and high fluence materials irradiations have been identified and approached. Collaborations are being pursued with both NASA and external experts to ensure that the results of the qualification testing are appropriate and relevant to nuclear fission power flight systems

    Spanning forest polynomials and the transcendental weight of Feynman graphs

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    We give combinatorial criteria for predicting the transcendental weight of Feynman integrals of certain graphs in ϕ4\phi^4 theory. By studying spanning forest polynomials, we obtain operations on graphs which are weight-preserving, and a list of subgraphs which induce a drop in the transcendental weight.Comment: 30 page

    Biased Information Search in Homogeneous Groups: Confidence as a Moderator for the Effect of Anticipated Task Requirements

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    When searching for information, groups that are homogeneous regarding their members’ prediscussion decision preferences show a strong bias for information that supports rather than conflicts with the prevailing opinion (confirmation bias). The present research examined whether homogeneous groups blindly search for information confirming their beliefs irrespective of the anticipated task or whether they are sensitive to the usefulness of new information for this forthcoming task. Results of three experiments show that task sensitivity depends on the groups’ confidence in the correctness of their decision: Moderately confident groups displayed a strong confirmation bias when they anticipated having to give reasons for their decision but showed a balanced information search or even a disconfirmation bias (i.e., predominately seeking conflicting information) when they anticipated having to refute unterarguments. In contrast, highly confident groups demonstrated a strong confirmation bias independent of the anticipated task requirements
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