The interaction between tolls and capacity investment in serial and parallel transport networks.

Investment; Serial; Transport; Networks; Working;

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic): Alewife/Blueback Herring

This profile covers life history and environmental requirements of both alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis), since their distribution is overlapping and their morphology, ecological role, and environmental requirements are similar. The alewife is an anadromous species found in riverine, estuarine, and Atlantic coastal habitats, depending on life cycle stage, from Newfoundland (Winters et al. 1973) to Soutn Carolina (Berry 1964). Landlocked populations are i n the Great Lakes, Finger Lakes, and many other freshwater lakes (Bigelow and Sch roeder 1953; Scott and Crossman 1973). The blueback herring is an anadromous species found in riverine, estuarine, and Atlantic coastal habitats, depending on life stage cycle, from Nova Scotia to the St. Johns River, Florida (Hildebrand 1963

Strategic investment and pricing decisions in a congested transport corridor.

This paper studies pricing and investment decisions on a congested transport corridor where the elements of the corridor are controlled by different governments. A corridor can be an interstate highway or railway line, or an inter-modal connection. We model the simplest corridor: two transport links in series, where each of the links is controlled by a different government. Each link is used by transit as well as by local traffic; both links are subject to congestion. We consider a two stage noncooperative game where both governments strategically set capacity in the first stage and play a pricing game in the second stage. Three pricing regimes are distinguished: (i) differentiated tolls between local and transit transport, (ii) one uniform toll on local and transit traffic, and (iii) only the local users can be tolled. Numerical analysis illustrates all theoretical insights. A number of interesting results are obtained. First, transit tolls on the network will be inefficiently high. If only local traffic can be tolled, however, the Nash equilibrium tolls are inefficiently low. Second, raising the toll on transit through a given country by one euro raises the toll on the whole trajectory by less than one euro. Third, higher capacity investment in a given region not only reduces optimal tolls in this region under all pricing regimes but it also increases the transit tolls on the other link of the corridor. Fourth, capacities in the different regions are strategic complements: when one country on the corridor increases transport capacity, it forces the other country to do the same. Fifth, we find interesting interactions between optimal capacities and the set of pricing instruments used: capacity with differentiated tolls is substantially higher than in the case of uniform tolls but overall welfare is lower. Finally, if transit is sufficiently important, it may be welfare improving not to allow any tolling at all, or to only allow the tolling of locals.Investment; Pricing; Decisions; Decision; Transport;

Niobium-based superconducting nano-devices fabrication using all-metal suspended masks

We report a novel method for the fabrication of superconducting nanodevices based on niobium. The well-known difficulties of lithographic patterning of high-quality niobium are overcome by replacing the usual organic resist mask by a metallic one. The quality of the fabrication procedure is demonstrated by the realization and characterization of long and narrow superconducting lines and niobium-gold-niobium proximity SQUIDs

On Pair Creation of Extremal Black Holes and Kaluza-Klein Monopoles

Classical solutions describing charged dilaton black holes accelerating in a background magnetic field have recently been found. They include the Ernst metric of the Einstein-Maxwell theory as a special case. We study the extremal limit of these solutions in detail, both at the classical and quantum levels. It is shown that near the event horizon, the extremal solutions reduce precisely to the static extremal black hole solutions. For a particular value of the dilaton coupling, these extremal black holes are five dimensional Kaluza-Klein monopoles. The euclidean sections of these solutions can be interpreted as instantons describing the pair creation of extremal black holes/Kaluza-Klein monopoles in a magnetic field. The action of these instantons is calculated and found to agree with the Schwinger result in the weak field limit. For the euclidean Ernst solution, the action for the extremal solution differs from that of the previously discussed wormhole instanton by the Bekenstein-Hawking entropy. However, in many cases quantum corrections become large in the vicinity of the black hole, and the precise description of the creation process is unknown.Comment: 45 pages, 5 figures, EFI-93-74, UCSBTH-93-38. (Omitted acknowledgements added, typos fixed

Air pollution from aircraft

A series of fundamental problems related to jet engine air pollution and combustion were examined. These include soot formation and oxidation, nitric oxide and carbon monoxide emissions mechanisms, pollutant dispension, flow and combustion characteristics of the NASA swirl can combustor, fuel atomization and fuel-air mixing processes, fuel spray drop velocity and size measurement, ignition and blowout. A summary of this work, and a bibliography of 41 theses and publications which describe this work, with abstracts, is included

Bianchi type IX asymptotical behaviours with a massive scalar field: chaos strikes back

We use numerical integrations to study the asymptotical behaviour of a homogeneous but anisotropic Bianchi type IX model in General Relativity with a massive scalar field. As it is well known, for a Brans-Dicke theory, the asymptotical behaviour of the metric functions is ruled only by the Brans-Dicke coupling constant with respect to the value -3/2. In this paper we examine if such a condition still exists with a massive scalar field. We also show that, contrary to what occurs for a massless scalar field, the singularity oscillatory approach may exist in presence of a massive scalar field having a positive energy density.Comment: 31 pages, 7 figures (low resolution

Evaluation of high-resolution forecasts with the non-hydrostaticnumerical weather prediction model Lokalmodell for urban air pollutionepisodes in Helsinki, Oslo and Valencia

International audienceThe operational numerical weather prediction model Lokalmodell LM with 7\,km horizontal resolution was evaluated for forecasting meteorological conditions during observed urban air pollution episodes. The resolution was increased to experimental 2.8 km and 1.1 km resolution by one-way interactive nesting without introducing urbanisation of physiographic parameters or parameterisations. The episodes examined are two severe winter inversion-induced episodes in Helsinki in December 1995 and Oslo in January 2003, three suspended dust episodes in spring and autumn in Helsinki and Oslo, and a late-summer photochemical episode in the Valencia area. The evaluation was basically performed against observations and radiosoundings and focused on the LM skill at forecasting the key meteorological parameters characteristic for the specific episodes. These included temperature inversions, atmospheric stability and low wind speeds for the Scandinavian episodes and the development of mesoscale recirculations in the Valencia area. LM forecasts often improved due to higher model resolution especially in mountainous areas like Oslo and Valencia where features depending on topography like temperature, wind fields and mesoscale valley circulations were better described. At coastal stations especially in Helsinki, forecast gains were due to the improved physiographic parameters (land fraction, soil type, or roughness length). The Helsinki and Oslo winter inversions with extreme nocturnal inversion strengths of 18°C were not sufficiently predicted with all LM resolutions. In Helsinki, overprediction of surface temperatures and low-level wind speeds basically led to underpredicted inversion strength. In the Oslo episode, the situation was more complex involving erroneous temperature advection and mountain-induced effects for the higher resolutions. Possible explanations include the influence of the LM treatment of snow cover, sea ice and stability-dependence of transfer and diffusion coefficients. The LM simulations distinctly improved for winter daytime and nocturnal spring and autumn inversions and showed good skill at forecasting further episode-relevant meteorological parameters. The evaluation of the photochemical Valencia episode concentrated on the dominating mesoscale circulation patterns and showed that the LM succeeds well in describing all the qualitative features observed in the region. LM performance in forecasting the examined episodes thus depends on the key episode characteristics and also the season of the year with a need to improve model performance in very stable inversion conditions not only for urban simulations

Nanoscale fillers. Fillers for high oxygen permeability polymer films

A wide range of polymer film products are available with varying degrees of permeability to a variety of gases, from oxygen to water to aromatic species. The barrier properties are determined primarily by the choice of the matrix polymer, and fine tailoring can be introduced through the addition of filler materials such as inorganic platelets and polymer blend materials. It was identified that hollow and porous addition of such particles appears little studied. Gel particles were prepared by free radical emulsion polymerisation of styrene and DVB in presence of hydrophobic solvents. Porous particles were prepared by the surfactant free emulsion copolymerisation of VBC and DVB, followed by Friedel- Crafts alkylation to yield hypercrosslinked microporous nanoparticles. Porous and gel particles were added to polymer films and the oxygen permeability and mechanical properties of these films determined. It was found that the addition of hypercrosslinked microporous nanoparticles increased the oxygen permeability of the films up to 〜50 % when added at 40 wt% loading. Further to these studies, hollow nanoparticles were prepared by the emulsion phase ATRP of DVB when initiated by mPEG-6-PS inisurf in the presence of a hydrophobic solvent