1,007 research outputs found

    A classification of plane and planar 2-trees

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    We present new functional equations for the species of plane and of planar (in the sense of Harary and Palmer, 1973) 2-trees and some associated pointed species. We then deduce the explicit molecular expansion of these species, i.e a classification of their structures according to their stabilizers. There result explicit formulas in terms of Catalan numbers for their associated generating series, including the asymmetry index series. This work is closely related to the enumeration of polyene hydrocarbons of molecular formula C_nH_n+2.Comment: 26 pages, 14 figure

    Digital Doppler extraction demonstration with the advanced receiver

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    A digital Doppler extraction demonstration with the Advanced Receiver 2 (ARX 2) tracking Pioneer 10 and Voyager 2 is described. The measured results are compared with those of the Block 4 receiver that was operating in parallel with the ARX 2. It is shown that the ARX 2 outperforms the Block 4 receiver in terms of Allan variance of the Doppler residuals, the amount of which depends on the scenario of interest

    Details on the O(meα6){\cal{O}}(m_e \alpha^6) Positronium Hyperfine Splitting due to Single Photon Annihilation

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    A detailed presentation is given of the analytic calculation of the single-photon annihilation contributions to the positronium ground state hyperfine splitting to order meα6m_e\alpha^6 in the framework of non-relativistic effective theories. The current status of the theoretical description of the positronium ground state hyperfine splitting is reviewed.Comment: 27 pages, latex, 5 postscript figures; typos correcte

    Right-Hand Polarized 4\u3ci\u3ef\u3c/i\u3e\u3csub\u3ece\u3c/sub\u3e Auroral Roar Emissions: 2. Nonlinear Generation Theory

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    Auroral roar emissions are commonly interpreted as Z (or upper hybrid) mode naturally excited by precipitating auroral electrons. Subsequent conversion to escaping radiation makes it possible for these emissions to be detected on the ground. Most emissions are detected as having left-hand (L) circular (or ordinary O) polarization, but the companion paper presents a systematic experimental study on the rare occurrence of the right-hand polarized, or equivalently, extraordinary (X) mode 4fce emission. A similar observation was reported earlier by Sato et al. (2015). The suggested emission mechanism is the nonlinear coalescence of two upper hybrid roars at 2fce. The present paper formulates a detailed theory for such an emission mechanism

    Treating Homeless Opioid Dependent Patients with Buprenorphine in an Office-Based Setting

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    CONTEXT Although office-based opioid treatment with buprenorphine (OBOT-B) has been successfully implemented in primary care settings in the US, its use has not been reported in homeless patients. OBJECTIVE To characterize the feasibility of OBOT-B in homeless relative to housed patients. DESIGN A retrospective record review examining treatment failure, drug use, utilization of substance abuse treatment services, and intensity of clinical support by a nurse care manager (NCM) among homeless and housed patients in an OBOT-B program between August 2003 and October 2004. Treatment failure was defined as elopement before completing medication induction, discharge after medication induction due to ongoing drug use with concurrent nonadherence with intensified treatment, or discharge due to disruptive behavior. RESULTS Of 44 homeless and 41 housed patients enrolled over 12 months, homeless patients were more likely to be older, nonwhite, unemployed, infected with HIV and hepatitis C, and report a psychiatric illness. Homeless patients had fewer social supports and more chronic substance abuse histories with a 3- to 6-fold greater number of years of drug use, number of detoxification attempts and percentage with a history of methadone maintenance treatment. The proportion of subjects with treatment failure for the homeless (21%) and housed (22%) did not differ (P=.94). At 12 months, both groups had similar proportions with illicit opioid use [Odds ratio (OR), 0.9 (95% CI, 0.5–1.7) P=.8], utilization of counseling (homeless, 46%; housed, 49%; P=.95), and participation in mutual-help groups (homeless, 25%; housed, 29%; P=.96). At 12 months, 36% of the homeless group was no longer homeless. During the first month of treatment, homeless patients required more clinical support from the NCM than housed patients. CONCLUSIONS Despite homeless opioid dependent patients' social instability, greater comorbidities, and more chronic drug use, office-based opioid treatment with buprenorphine was effectively implemented in this population comparable to outcomes in housed patients with respect to treatment failure, illicit opioid use, and utilization of substance abuse treatment

    A Model of Zebra Emission in Solar Type IV Radio Bursts

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    Solar type IV radio bursts present a theoretical challenge because they are composed of both continuum emission and fine structures. The latter include zebra bursts, which appear as harmonically spaced multiplets that shift in frequency with time. Similarities between these features and terrestrial auroral emissions suggest a new model to explain zebra-structured type IV emissions. In this model, the basic generation mechanism is identical with that proposed by Winglee and Dulk: mode conversion of Z-mode waves generated by the cyclotron maser mechanism under the condition fuh = Nfce, with N an integer; however, we propose a twist on this model whereby the zebra bursts do not arise from multiple N-values. Rather, the presence of localized density irregularities within the type IV source region leads to trapping of the upper hybrid Z-mode waves in density enhancements, which results in a discrete spectrum of upper hybrid modes with nearly constant frequency spacing. The number m of quasi-harmonics is limited by the trapping (quantization) conditions. The problem is described by an equivalent Schrödinger equation for the trapped mode, which is solved for an (idealized) cylindrical square density irregularity. In this model, the eigenfrequency spacing matches the observed type IV frequency spacings for less than 10% density enhancements with individual scale sizes of 30-1000 thermal electron gyroradii, corresponding to 1-100 m scales in coronal loops. To produce the observed emitted power for a reasonable (\u3c1%) efficiency requires a large number of such individual microscopic sources occurring over a portion of a magnetic type IV loop at a restricted altitude within which the magnetic field and density are approximately constant. The loop plasma in the zebra emission source is thus highly turbulent in the sense that it contains a large number of density fluctuations. In this case transition radiation can effectively contribute to the radiation background and may also provide the wave power required in the upper hybrid range for generating zebra emissions

    Division Algebras and Extended N=2,4,8 SuperKdVs

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    The first example of an N=8 supersymmetric extension of the KdV equation is here explicitly constructed. It involves 8 bosonic and 8 fermionic fields. It corresponds to the unique N=8 solution based on a generalized hamiltonian dynamics with (generalized) Poisson brackets given by the Non-associative N=8 Superconformal Algebra. The complete list of inequivalent classes of parametric-dependent N=3 and N=4 superKdVs obtained from the ``Non-associative N=8 SCA" is also furnished. Furthermore, a fundamental domain characterizing the class of inequivalent N=4 superKdVs based on the "minimal N=4 SCA" is given.Comment: 14 pages, LaTe

    A note on the third family of N=2 supersymmetric KdV hierarchies

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    We propose a hamiltonian formulation of the N=2N=2 supersymmetric KP type hierarchy recently studied by Krivonos and Sorin. We obtain a quadratic hamiltonian structure which allows for several reductions of the KP type hierarchy. In particular, the third family of N=2N=2 KdV hierarchies is recovered. We also give an easy construction of Wronskian solutions of the KP and KdV type equations

    Relativistic and Binding Energy Corrections to Direct Photon Production In Upsilon Decay

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    A systematic gauge-invariant method is used to calculate the rate for an upsilon meson to decay inclusively into a prompt photon. An expansion is made in the quark relative velocity v, which is a small natural parameter for heavy quark systems. Inclusion of these O(v^2) corrections tends to increase the photon rate in the middle z range and to lower it for larger z, a feature supported by the data.Comment: 13 pages, LateX, One figure (to be published in Phys. Rev. D, Sept. 1, 1996
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