4,722 research outputs found

    Cycling & Urban Commuting: Results of Behavioural Mode and Route Choice Models

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    The research reported here was undertaken as part of an Economic and Social Research Council Project (R000237103) entitled Cycling and Urban Mode Choice. The scope of the study is entirely commuting within an urban context. The objectives of the study were: • to better understand the interactions between car, bus, cycle and walk in an urban context and to explain observed variations in cycle trip rates across towns. • to be able to forecast the effect of a range of improvements to cycling facilities on mode choice • to use the estimated models to evaluate some actual schemes • to provide end users (eg consultants, local authorities, cycling organisations) with a tool to determine the effect of policy measures. In particular, to create models which will enhance the performance of strategic, integrated transport studies. The objectives of this paper are: • to describe the methodology that was used to examine cycling within an urban mode choice context • to outline the collection of data required to estimate behavioural models • to report the results of the estimated mode and route choice models • to provide illustrations of how the model can be used to appraise improvements to cycle facilities and cycling conditions. The structure of this paper is as follows. Section 2 gives a brief overview of the policy context of work on cycling in the UK and previous work in the area. Section 3 describes the methodology used to collect the Revealed Preference (RP) and Stated Preference (SP) data necessary for the model. Section 4 describes the data that was collected. Section 5 gives details of the development of the model and some empirical results from the model that was developed. Section 6 illustrates how the model could be used to appraise improvements in cycle facilities and cycling conditions. Section 7 draws some conclusions from the work

    Elastic and inelastic breakup of deuterons with energy below 100 MeV

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    We present calculations of deuteron elastic and inelastic breakup cross sections and angular distributions at deuteron energies below 100 MeV obtained using the post-form DWBA approximation. The elastic breakup cross section was extensively studied in the past. Very few calculations of inelastic breakup have been performed, however. We also analyze the angular momentum - energy distributions of the cross section for formation of the compound nucleus after inelastic breakup.Comment: 7 page

    Excitation and emission spectra of rubidium in rare-gas thin-films

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    To understand the optical properties of atoms in solid state matrices, the absorption, excitation and emission spectra of rubidium doped thin-films of argon, krypton and xenon were investigated in detail. A two-dimensional spectral analysis extends earlier reports on the excitation and emission properties of rubidium in rare-gas hosts. We found that the doped crystals of krypton and xenon exhibit a simple absorption-emission relation, whereas rubidium in argon showed more complicated spectral structures. Our sample preparation employed in the present work yielded different results for the Ar crystal, but our peak positions were consistent with the prediction based on the linear extrapolation of Xe and Kr data. We also observed a bleaching behavior in rubidium excitation spectra, which suggests a population transfer from one to another spectral feature due to hole-burning. The observed optical response implies that rubidium in rare-gas thin-films is detectable with extremely high sensitivity, possibly down to a single atom level, in low concentration samples.Comment: 7 pages, 5 figure

    Photo-emission rate of sQGP at finite density

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    We calculate the thermal spectral function of SYM plasma with finite density using holographic technique. We take the RN-AdS black hole as the dual gravity theory. In the presence of charge, vector modes of gravitational and electromagnetic perturbation are coupled with each other. By introducing master variables for these modes, we solve the coupled system and calculate spectral function. We also calculated photoemission rate of SYM plasma from spectral function for light like momentum, AC conductivity and their density dependence. The suppression of the conductivity in high density is noticed, which might be yet another mechanism for the Jet quenching phenomena in RHIC experiment.Comment: 27 pages, 10 figure

    Threshold corrections to the radiative breaking of electroweak symmetry and neutralino dark matter in supersymmetric seesaw model

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    We study the radiative electroweak symmetry breaking and the relic abundance of neutralino dark matter in the supersymmetric type I seesaw model. In this model, there exist threshold corrections to Higgs bilinear terms coming from heavy singlet sneutrino loops, which make the soft supersymmetry breaking (SSB) mass for up-type Higgs shift at the seesaw scale and thus a minimization condition for the Higgs potential is affected. We show that the required fine-tuning between the Higgsino mass parameter mu and the SSB mass for up-type Higgs may be reduced at the electroweak scale, due to the threshold corrections. We also present how the parameter mu depends on the SSB B-parameter for heavy singlet sneutrinos. Since the property of neutralino dark matter is quite sensitive to the size of mu, we discuss how the relic abundance of neutralino dark matter is affected by the SSB B-parameter. Taking the SSB B-parameter of order of a few hundreds TeV, the required relic abundance of neutralino dark matter can be correctly achieved. In this case, dark matter is a mixture of bino and Higgsino, under the condition that gaugino masses are universal at the grand unification scale.Comment: 27 pages, 3 figures; references added, discussion about RGEs added, the version published on PR

    Control of Alternaria alternata, Causal Agent of Dead (Dormant) Flower Bud Disease of Pear

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    Dead (dormant) flower buds of pear are an important phenomenon in pear production in the Netherlands. Vigourous or unbalanced tree growth and Pseudomonas syringae pv. syringae (P.s.s.) are mentioned as likely causes of dead flower buds. Pseudomonas syringae pv. syringae was occasionally isolated from diseased flower buds. However, Alternaria alternata was nearly always isolated from diseased buds and also often in symptomless flower buds. By identifying the causal agent of dead flower buds disease, an effective control strategy can be developed. In field trials it was proven that fungicide treatments can reduce disease incidences significantly

    Possible Deviation from the Tri-bimaximal Neutrino Mixing in a Seesaw Model

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    We propose a simple but suggestive seesaw model with two phenomenological conjectures: three heavy (right-handed) Majorana neutrinos are degenerate in mass in the symmetry limit and three light Majorana neutrinos have the tri-bimaximal mixing pattern V0V^{}_0. We show that a small mass splitting between the first generation and the other two generations of heavy Majorana neutrinos is responsible for the deviation of the solar neutrino mixing angle θ12\theta^{}_{12} from its initial value 35.335.3^\circ given by V0V^{}_0, and the slight breaking of the mass degeneracy between the second and third generations of heavy Majorana neutrinos results in a small mixing angle θ13\theta^{}_{13} and a tiny departure of the atmospheric neutrino mixing angle θ23\theta^{}_{23} from 4545^\circ. It turns out that a normal hierarchy of the light neutrino mass spectrum is favored in this seesaw scenario.Comment: RevTex 12 pages (2 EPS figures included). More discussions and references adde
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