9,230 research outputs found
Pricing Methods
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
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.
Radio Emission from the Composite Supernova Remnant G326.3-1.8 (MSH15-56)
High resolution radio observations of the composite supernova remnant (SNR)
G326.3-1.8 or MSH 15-56 with the Australia Telescope Compact Array show details
of both the shell and the bright plerion which is offset about 1/3 of the
distance from the center of the SNR to the shell. The shell appears to be
composed of thin filaments, typical of older shell SNRs. The central part of
the elongated plerion is composed of a bundle of parallel ridges which bulge
out at the ends and form a distinct ring structure on the northwestern end. The
magnetic field with a strength of order 45 microGauss, is directed along the
axis of the ridges but circles around the northwestern ring. This plerion is
large and bright in the radio but is not detected in x-ray or optical
wavelengths. There is, however, a faint hard x-ray feature closer to the shell
outside the plerion. Perhaps if the supernova explosion left a rapidly moving
magnetar with large energy input but initially rapid decay of both relativistic
particles and magnetic field, the observed differences with wavelength could be
explained.Comment: 15 pages, 10 figures, accepted by Ap
Searching for annihilation radiation from SN 1006 with SPI on INTEGRAL
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 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 3 flux upper limit of 0.59 x 10 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 10 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.
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
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.
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
Late Light Curves of Normally-Luminous Type Ia Supernovae
The use of Type Ia supernovae as cosmological tools has reinforced the need
to better understand these objects and their light curves. The light curves of
Type Ia supernovae are powered by the nuclear decay of . The late time light curves can provide insight into the behavior of
the decay products and their effect of the shape of the curves. We present the
optical light curves of six "normal" Type Ia supernovae, obtained at late times
with template image subtraction, and the fits of these light curves to
supernova energy deposition models.Comment: Proceedings of Astronomy with Radioactivities V Conferenc
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