1,904 research outputs found

    Partialy Paradoxist Smarandache Geometries

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    A paradoxist Smarandache geometry combines Euclidean, hyperbolic, and elliptic geometry into one space along with other non-Euclidean behaviors oflines that would seem to require a discrete space. A class of continuous spaces is presented here together with specific examples that emibit almost all of these phenomena and suggest the prospect of a continuous paradoxist geometry

    Polarization observables in dp backward elastic scattering at high and intermediate energies

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    The tensor analyzing power T20T_{20} and the polarization transfer coefficients κ0(=3/2Kyy)\kappa_0 (= 3/2 K_y^y) and KxzyK_{xz}^y are investigated for dp backward elastic scattering by the invariant-amplitude method. Discrepancies between the conventional calculations and the experimental data on T20T_{20} and κ0\kappa_0 at high and intermediate energies are mostly dissolved by including imaginary parts in the amplitudes. The quantity KxzyK_{xz}^y is shown to be useful in criticizing nuclear force assumptions.Comment: 10 pages, LaTeX, 3 Postscript figure

    Determination of S17 from 8B breakup by means of the method of continuum-discretized coupled-channels

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    The astrophysical factor for 7Be(p,\gamma)8B at zero energy, S17(0), is determined from an analysis of 208Pb(8B, p+7Be)208Pb at 52 MeV/nucleon by means of the method of continuum-discretized coupled-channels (CDCC) taking account of all nuclear and Coulomb breakup processes. The asymptotic normalization coefficient (ANC) method is used to extract S17(0) from the calculated breakup-cross-section. The main result of the present paper is S17(0)=20.9 +2.0/-1.9 eV b. The error consists of 8.4% experimental systematic error and the error due to the ambiguity in the s-wave p-7Be scattering length. This value of S17(0) differs from the one extracted with the first-order perturbation theory including Coulomb breakup by dipole transitions: 18.9 +/- 1.8 eV b. It turns out that the difference is due to the inclusion of the nuclear and Coulomb-quadrupole transitions and multi-step processes of all-order in the present work. The p-7Be interaction potential used in the CDCC calculation is also used in the ANC analysis of 7Be(p,\gamma)8B. The value of S17(0)=21.7 +0.62/-0.55 eV b obtained is consistent with the previous one obtained from a precise measurement of the p-capture reaction cross section extrapolated to zero incident energy, S17(0)=22.1 +/- 0.6 (expt) +/- 0.6 (theo) eV b, where (theo) stands for the error in the extrapolation. Thus, the agreement between the values of S17(0) obtained from direct 7Be(p,\gamma)8B and indirect 8B-breakup measurements is significantly improved.Comment: 13 pages, 9 figures, published in PR

    Flatfish herding behavior in response to trawl sweeps: a comparison of diel responses to conventional sweeps and elevated sweeps

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    Commercial bottom trawls often have sweeps to herd fish into the net. Elevation of the sweeps off the seaf loor may reduce seafloor disturbance, but also reduce herding effectiveness. In both field and laboratory experiments, we examined the behavior of flatfish in response to sweeps. We tested the hypotheses that 1) sweeps are more effective at herding flatfish during the day than at night, when fish are unable to see approaching gear, and that 2) elevation of sweeps off the seafloor reduces herding during the day, but not at night. In sea trials, day catches were greater than night catches for four out of six flatfish species examined. The elevation of sweeps 10 cm significantly decreased catches during the day, but not at night. Laboratory experiments revealed northern rock sole (Lepidopsetta polyxystra) and Pacific halibut (Hippoglossus stenolepis) were more likely to be herded\ud by the sweep in the light, whereas in the dark they tended to pass under or over the sweep. In the light, elevation of the sweep reduced herding, and more fish passed under the sweep. In contrast, in the dark, sweep elevation had little effect upon the number of fish that exhibited herding behavior. The results of both field and laboratory experiments were consistent with the premise that vision is the principle sensory input that controls fish behavior and orientation to trawl gear, and gear performance will differ between conditions where flatfish can see, in contrast to where they cannot see, the approaching gear

    Continuum-discretized coupled-channels method for four-body breakup reactions

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    Development of the method of CDCC (Continuum-Discretized Coupled-Channels) from the level of three-body CDCC to that of four-body CDCC is reviewed. Introduction of the pseudo-state method based on the Gaussian expansion method for discretizing the continuum states of two-body and three-body projectiles plays an essential role in the development. Furthermore, introduction of the complex-range Gaussian basis functions is important to improve the CDCC for nuclear breakup so as to accomplish that for Coulomb and nuclear breakup. A successful application of the four-body CDCC to 6^6He+12^{12}C scattering at 18 and 229.8 MeV is reported.Comment: Latex file of revtex4 class, 14 pages, 10 figures. A talk given at the Workshop on Reaction Mechanisms for Rare Isotope Beams, Michigan State University, March 9-12, 2005 (to appear in an AIP Conference Proceedings

    Gaussian expansion approach to Coulomb breakup

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    An accurate treatment of Coulomb breakup reactions is presented by using both the Gaussian expansion method and the method of continuum discretized coupled channels. As L2L^2-type basis functions for describing bound- and continuum-states of a projectile, we take complex-range Gaussian functions, which form in good approximation a complete set in a large configuration space being important for Coulomb-breakup processes. Accuracy of the method is tested quantitatively for 8B+58^{8}{\rm B}+^{58}Ni scattering at 25.8 MeV.Comment: 4 pages, 4 figures; typos removed, a reference added for introduction and submitted to Phys. Rev. C as a brief repor

    Coulomb breakup effects on the elastic cross section of 6^6He+209^{209}Bi scattering near Coulomb barrier energies

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    We accurately analyze the 6^6He+209^{209}Bi scattering at 19 and 22.5 MeV near the Coulomb barrier energy, using the continuum-discretized coupled-channels method (CDCC) based on the nn+nn+4^4He+209^{209}Bi four-body model. The three-body breakup continuum of 6^6He is discretized by diagonalizing the internal Hamiltonian of 6^6He in a space spanned by the Gaussian basis functions. The calculated elastic and total reaction cross sections are in good agreement with the experimental data, while the CDCC calculation based on the di-neutron model of 6^6He, i.e., the 2n^2n+4^{4}He+209^{209}Bi three-body model, does not reproduce the data.Comment: 5 pages, 5 figures, uses REVTeX 4, submitted to Phys. Rev.

    Laws of the media, their environments and their users: The flip of the artifact, of its ground and its user

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    Marshall McLuhan’s Laws of Media (LOM), which describe the evolution of artifacts in terms of enhancement, obsolescence, retrieval and reversal (or flip) are extended to create Laws of Media Environments (LOME) and Laws of Media Users (LOMU). It is shown that the environment or ground in which the figures of the artifacts in the LOM operate and the users of those artifacts undergo respectively a similar evolution of enhancement, obsolescence, retrieval and reversal paralleling McLuhan’s original LOM
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