5,037 research outputs found

    Rail transit fare collection: Policy and technology assessment

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    The impact of fare policies and fare structure on the selection of equipment was investigated, fare collection systems are described, hardware and technology related problems are documented, and the requirements of a fare collection simulation model are outlined. Major findings include: (1) a wide variation in the fare collection systems and equipment, caused primarily by historical precedence; (2) the reliability of AFC equipment used at BART and WMATA discouraged other properties from considering use of similar equipment; (3) existing equipment may not meet the fare collection needs of properties in the near future; (4) the cost of fare collection operation and maintenance is high; and (5) the relatively small market in fare collection equipment discourages new product development by suppliers. Recommendations for fare collection R&D programs include development of new hardware to meet rail transit needs, study of impacts of alternate fare policies increased communication among policymakers, and consensus on fare policy issues

    Hybrid vehicle assessment. Phase 1: Petroleum savings analysis

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    The results of a comprehensive analysis of near term electric hybrid vehicles are presented, with emphasis on their potential to save significant amounts of petroleum on a national scale in the 1990s. Performance requirements and expected annual usage patterns of these vehicles are first modeled. The projected U.S. fleet composition is estimated, and conceptual hybrid vehicle designs are conceived and analyzed for petroleum use when driven in the expected annual patterns. These petroleum consumption estimates are then compared to similar estimates for projected 1990 conventional vehicles having the same performance and driven in the same patterns. Results are presented in the form of three utility functions and comparisons of sevral conceptual designs are made. The Hybrid Vehicle (HV) design and assessment techniques are discussed and a general method is explained for selecting the optimum energy management strategy for any vehicle mission battery combination. Conclusions and recommendations are presented, and development recommendations are identified

    Curriculum Vitae (Feminae): Biography and Early American Women Lawyers

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    In this review, Carol Sanger examines the recent surge of interest in the lives of early women lawyers. Using Jane Friedman\u27s biography of Myra Bradwell, America\u27s First Woman Lawyer, as a starting point, Professor Sanger explores the complexities for the feminist biographer of reconciling for herself and for her subject conflicting professional, political, and personal sensibilities. Professor Sanger concludes that to advance the project of women\u27s history, feminist biographers ought not retreat to the comforts of commemorative Victorian biography, even for Victorian subject, but should instead strive to present and accept early women subjects on their own complex terms

    CP-Violation For BXsl+lB \to X_sl^+l^- Including Long-Distance Effects

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    We consider the CP violating effect for BXsl+lB\to X_sl^+l^- process, including both short and long distance effects. We obtain the CP asymmetry parameter and present its variation over the dilepton mass.Comment: 9 pages, Latex file, one figure include

    Electroweak Model Independent Tests for SU(3) Symmetry in Hadronic B Decays

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    We study effects of new physics beyond the Standard Model on SU(3) symmetry in charmless hadronic two body B decays. It is found that several equalities for some of the decay amplitudes, such as A(Bd(Bu)π+π,π+K(πKˉ0))=A(BsK+π,KK+(K0Kˉ0))A(B_d (B_u) \to \pi^+\pi^-,\pi^+ K^- (\pi^- \bar K^0)) =A(B_s \to K^+ \pi^-, K^- K^+ (K^0 \bar K^0)), A(Bdπ+ρ,πρ+,Kρ+,π+K)=A(BsK+ρ,πK+,KK+,K+K)A(B_d \to \pi^+\rho^-, \pi^- \rho^+, K^-\rho^+, \pi^+ K^{*-}) = A(B_s \to K^+ \rho^-, \pi^- K^{*+}, K^- K^{*+}, K^+ K^{*-}), A(Bd(Bu)ρ+ρ,ρ+K(ρKˉ0))=A(BsK+ρ,KK+(K0Kˉ0))A(B_d (B_u) \to \rho^+\rho^-, \rho^+ K^{*-}(\rho^- \bar K^{*0})) =A(B_s \to K^{*+} \rho^-, K^{*-} K^{*+} (K^{*0} \bar K^{*0})), predicted by SU(3) symmetry in the SM are not affected by new physics. These relations provide important electroweak model independent tests for SU(3) symmetry in B decays.Comment: 4 pages, revte

    Texture of fermion mass matrices in partially unified theories

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    We investigate the texture of fermion mass matrices in theories with partial unification (for example SU(2)L×SU(2)R×SU(4)c SU(2)_L\times SU(2)_R\times SU(4)_c) at a scale 1012\sim 10^{12} GeV. Starting with the low energy values of the masses and the mixing angles, we find only two viable textures with atmost four texture zeros. One of these corresponds to a somewhat modified Fritzsch textures. A theoretical derivataion of these textures leads to new interesting relations among the masses and the mixing angles.Comment: 10 pages(Latex

    Analysis of Charge Asymmetry in Rare Dilepton BB Decays

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    We analyze forward-backward charge asymmetry of the lepton production in rare decays BXsl+lB\rightarrow X_s l^+l^- and BKl+lB\rightarrow K^* l^+l^-, including vector-resonance effects. Certain regions of phase space, in which the asymmetry is sensitive to individual short-distance coefficients, are pointed out. In particular, we suggest a method to test the coupling of the leptonic axial vector current to the left-handed quark current experimentally.Comment: 27 pages, 4 figures available up to requiremen

    Semi-Inclusive B\to K(K^*) X Decays with Initial Bound State Effects

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    The effects of initial bb quark bound state for the semi-inclusive decays BK(K)XB\to K(K^*) X are studied using light cone expansion and heavy quark effective theory methods. We find that the initial bound state effects on the branching ratios and CP asymmetries are small. In the light cone expansion approach, the CP-averaged branching ratios are increased by about 2% with respect to the free bb-quark decay. For Bˉ0K(K)X\bar B^0 \to K^- (K^{*-}) X, the CP-averaged branching ratios are sensitive to the phase γ\gamma and the CP asymmetry can be as large as 7% (14%), whereas for BKˉ0(Kˉ0)XB^-\to \bar K^0 (\bar K^{*0})X the CP-averaged branching ratios are not sensitive to γ\gamma and the CP asymmetries are small (<1< 1%). The CP-averaged branching ratios are predicted to be in the ranges (0.531.5)×104(0.53 \sim 1.5)\times 10^{-4} [(0.252.0)×104(0.25 \sim 2.0)\times 10^{-4}] for Bˉ0K(K)X\bar B^0 \to K^- (K^{*-})X and (0.770.84)×104(0.77 \sim 0.84)\times 10^{-4} [(0.670.74)×104(0.67 \sim 0.74)\times 10^{-4}] for BKˉ0(Kˉ0)XB^-\to \bar K^0 (\bar K^{*0}) X, depending on the value of the CP violating phase γ\gamma. In the heavy quark effective theory approach, we find that the branching ratios are decreased by about 10% and the CP asymmetries are not affected. These predictions can be tested in the near future.Comment: 29 pages, 12 ps figure

    One-loop flavor changing electromagnetic transitions

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    We discuss the effect of the external fermion masses in the flavor-changing radiative transitions of a heavy fermion (quark or lepton) to a lighter fermion at the one-loop level, and point out an often overlooked crucial difference in the sign of a charge factor between transitions of the down type sdγs\to d\gamma and the up type cuγc\to u\gamma. We give formulas for the FfγF\to f\gamma effective vertex in various approximations and the exact formula for tcγt\to c\gamma and τμγ\tau \to \mu \gamma.Comment: LaTeX 16 pages + 4 postscript figures. Misprints corrected, some Comments adde

    The electronic and magnetic properties of La0.85Zr0.15MnO3 deposited on SrTiO3 and MgO substrates

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    [[abstract]]The electronic and magnetic properties of tetravalent-ion-doped La0.85Zr0.15MnO3 (LZMO) thin films that were epitaxially grown on SrTiO3 (STO) and MgO substrates were studied using temperature-dependent x-ray diffraction (XRD), x-ray absorption near-edge structure, x-ray linear dichroism, and x-ray magnetic circular dichroism at the Mn L 3,2- and K-edge. XRD studies reveal that the LZMO thin films have compressive and tensile strains (along the c -axis) on the STO and MgO substrates, respectively. As the temperature is reduced from room temperature to below magnetic transition temperature, the preferentially occupied Mn majority-spin e g orbital changes from the in-plane dx 2 -y 2 to the out-of-plane d 3 z 2 -r 2 orbital for LZMO/STO, and vice versa for LZMO/MgO. Experimental results suggest that the new hopping path that is mediated by the Mn2+ ions triggers a stronger d 3 z 2 -r 2 orbital ordering of Mn3+ ions and enhances the ferromagnetic coupling between the Mn spin moments of t 2g electrons in LZMO/STO, whereas the strong tensile strain stabilizes the dx 2 -y 2 orbital by inducing lattice distortions of the MnO6 octahedra in LZMO/MgO.[[notice]]補正完畢[[incitationindex]]SCI[[cooperationtype]]國
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