11,188 research outputs found

    Pricing Methods

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    In order to consider the range of pricing methods available, it is first necessary to choose a definition for road pricing. The term "road pricing" has been criticised as an inaccurate description of systems which is applied to (Thompson, 1990) and there is some inconsistency regarding the extent of charging policies which are considered to be included. A liberal definition could cover any fiscal form of traffic restraint, affecting the mode, time, route, destination of frequency of journeys. In this case road pricing already exists worldwide through taxes imposed upon the purchase and licensing of vehicles and through fuel taxation. The extension of conventional taxation arrangements has been used as part of road pricing strategies in both Hong Kong and Singapore (Dawson and Brown, 1985; LPAC, 1991). However, the essence of most road pricing work has been to replace and supplement these existing charges, which do not discriminate by time, location or amount of vehicle use, with charging structures which are directly related to these issues. For this reason the descriptions road-use pricing, congestion pricing and road user charging are sometimes preferred, and some recent texts have attempted to impose a narrower definition for road pricing, in which only charging systems relating directly to the time and distance travelled are included (CIT, 1992). For the purposes of this review it is best to retain the conventional term of road pricing and apply the broadest definition

    The New Zealand Chinese gooseberry export industry and its future development : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Agricultural Economics at Massey University

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    New Zealand's dependence on the traditional exports, meat, wool, butter and cheese for the major overseas earners is well documented, (see (1)). New Zealand is one of the world's most efficient producers of these commodities but market access and short term political and social expediency has tended to reduce the gains of economic rationalization. During the last year (1971) butter and cheese have been placed in long term jeopardy due to Britain's impending union1 1. This is not an unexpected development. Britain first applied for membership in 1961 and was rejected in 1963 - negotation restarted in 1966 and entry will date from the 1/1/73. However, the provisions of the Common Agricultural Policy will not come into force until 1/1/74. with the European Economic Community. Wool suffered a serious price reversal in 1967 and although a price revival has occurred in the past year it is doubtful if this will be a long term recovery. Lamb exports to the U.K. are experiencing greater competition than ever from other meats, especially cheaply produced poultry. The beef quota for the U.S.A. cannot be considered safe as it depends to a large extent on seasonal production variations in the U.S.A. and the strength of the U.S.A. farm lobby. The existence of tariff and non-tariff barriers to trade, together with low price and income elasticities of demand for primary exports has placed emphasis on manufactured exports and import substitution in New Zealand, but many attempts at such diversification are often misdirected.2 2.An obvious example of this in New Zealand - The Automobile Industry. (see The World Bank Report on the New Zealand Economy 1968) though the farming industry has some protected sectors also. New Zealand has no absolute or comparative advantage in citrus production, hop production, wheat production - consequently all are protected by trade barriers in common with many other countries. Condliffe (5) has a cautionary note about this: "It is necessary to aim at competitive production for the world market rather than protected production for a small local market.

    Searching for annihilation radiation from SN 1006 with SPI on INTEGRAL

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    Historical Type Ia supernovae are a leading candidate for the source of positrons observed through their diffuse annihilation emission in the Galaxy. However, search for annihilation emission from individual Type Ia supernovae has not been possible before the improved sensitivity of \integral. The total 511 keV annihilation flux from individual SNe Ia, as well as their contribution to the overall diffuse emission, depends critically on the escape fraction of positrons produced in 56^{56}Co decays. Late optical light curves suggest that this fraction may be as high as 5%. We searched for positron annihilation radiation from the historical Type Ia supernova SN 1006 using the SPI instrument on \integral. We did not detect significant 511 keV line emission, with a 3σ\sigma flux upper limit of 0.59 x 104^{-4} ergs cm^-2 s^-1 for \wsim 1 Msec exposure time, assuming a FWHM of 2.5 keV. This upper limit corresponds to a 7.5% escape fraction, 50% higher than the expected 5% escape scenario, and rules out the possibility that Type Ia supernovae produce all of the positrons in the Galaxy (~ 12% escape fraction), if the mean positron lifetime is less than 105^{5} years. Future observations with \integral will provide stronger limits on the escape fraction of positrons, the mean positron lifetime, and the contribution of Type Ia supernovae to the overall positron content of the Galaxy.Comment: 3 pages, 2 figures, accepted for publication in ApJ

    Modelling the Network Effects of Road User Charging: Results from a SATURN Study.

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    The aim of this research has been to investigate the modelled effects of alternative road user charging systems upon an existing road network using the congested assignment models SATURN and CONTRAM applied to the city of Cambridge. Four road user charging systems which are being considered for practical application have been tested. These are toll cordons, time-based charging, a congestion charging system similar to that proposed in Cambridge and distance-based charging. Tests have been conducted using current morning peak travel demand patterns both with a fixed trip matrix, to isolate rerouteing issues and using the SATURN elastic assignment program, SATEASY, in order to address the effects of charging upon the frequency, timing and distribution of trips. Network impacts have been assessed using a series global indicators, in particular effects on vehicle-km, vehicle-hours and the resulting average network speeds. In addition, results have been obtained for total delay times, cordon crossing flows and revenues generated from charging. These results are presented and their implications discussed

    The ASCA Spectrum of the Vela Pulsar Jet

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    ROSAT observations of the Vela pulsar and its surroundings revealed a collimated X-ray feature almost 45' in length (Markwardt & Ogelman 1995), interpreted as the signature ``cocoon'' of a one-sided jet from the Vela pulsar. We report on a new ASCA observation of the Vela pulsar jet at its head, the point where the jet is believed to interact with the supernova remnant. The head is clearly detected, and its X-ray spectrum is remarkably similar to the surrounding supernova remnant spectrum, extending to X-ray energies of at least 7 keV. A ROSAT+ASCA spectrum can be fit by two-component emission models but not standard one-component models. The lower energy component is thermal and has a temperature of 0.29+/-0.03 keV (1 sigma); the higher energy component can be fit by either a thermal component of temperature ~4 keV or a power law with photon index ~2.0. Compared to the ROSAT-only results, the mechanical properties of the jet and its cocoon do not change much. If the observed spectrum is that of a hot jet cocoon, then the speed of the jet is at least 800 km s^-1, depending on the angle of inclination. The mechanical power driving the jet is >10^36 erg s^-1, and the mass flow rate at the head is > 10^-6 M_sun yr^-1. We conclude that the jet must be entraining material all along its length in order to generate such a large mass flow rate. We also explore the possibility that the cocoon emission is synchrotron radiation instead of thermal.Comment: 12 pages, LaTeX in AAS v4.0 preprint style, two PS figures, accepted for publication in the ApJ Letter

    The Distributional Impact of Various Road Charging Schemes for London.

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    This Working Paper presents results obtained using the MVA START model for London, with the primary intention of investigating the distributional impact of road pricing in various forms and at various levels. In order to look at distributional effects the START model had to be 'disaggregated' by income groups - three each for non-car owning and car-owning households. Initially, this allowed us to see the distributional impact of the LPAC Preferred Strategy, mainly involving public transport and traffic management policies. Beyond this we tested three structures (or 'regimes') of road pricing, varying from a complex three cordon plus screenlines structure, to a single Central London cordon. Somewhat surprisingly, the latter was found to be regressive in its application. The structure with the highest benefits, as well as being relatively progressive, was the complex structure of three cordons plus screenlines, with an optimum charge level of 50 pence per cordon crossing, each way but with the outer two cordons being peak only

    Emergent charge ordering in near half doped Na0.46_{0.46}CoO2_{2}

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    We have utilized neutron powder diffraction to probe the crystal structure of layered Nax_{x}CoO2_{2} near the half doping composition of x=x=0.46 over the temperature range of 2 to 600K. Our measurements show evidence of a dynamic transition in the motion of Na-ions at 300K which coincides with the onset of a near zero thermal expansion in the in-plane lattice constants. The effect of the Na-ordering on the CoO2_{2} layer is reflected in the octahedral distortion of the two crystallographically inequivalent Co-sites and is evident even at high temperatures. We find evidence of a weak charge separation into stripes of Co+3.5+ϵ^{+3.5+\epsilon} and Co+3.5ϵ^{+3.5-\epsilon}, ϵ0.06e\epsilon\sim0.06e below \Tco=150K. We argue that changes in the Na(1)-O bond lengths observed at the magnetic transition at \tm=88K reflect changes in the electronic state of the CoO2_{2} layerComment: 7 pages, 6 figures, in press Phys. Rev.

    Quantum steering ellipsoids, extremal physical states and monogamy

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    A Corrigendum for this article has been published in 2015 New J. Phys. 17 019501Any two-qubit state can be faithfully represented by a steering ellipsoid inside the Bloch sphere, but not every ellipsoid inside the Bloch sphere corresponds to a two-qubit state. We give necessary and sufficient conditions for when the geometric data describe a physical state and investigate maximal volume ellipsoids lying on the physical-unphysical boundary. We derive monogamy relations for steering that are strictly stronger than the Coffman-Kundu- Wootters (CKW) inequality for monogamy of concurrence. The CKW result is thus found to follow from the simple perspective of steering ellipsoid geometry. Remarkably, we can also use steering ellipsoids to derive non-trivial results in classical Euclidean geometry, extending Eulers inequality for the circumradius and inradius of a triangle.The EPSRC and the ARC Centre of Excellence grant no. CE110001027. DJ is funded by the Royal Society. TR would like to thank the Leverhulme Trust. SJ acknowledges EPSRC grant EP/ K022512/1
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