Shorebased Processor Outcomes Under Catch Shares

Abstract

Fishery management measures often aim to regulate harvesting behavior but can have downstream effects on fish processors, output markets, and consumers. Empirical analysis of these impacts is generally limited due to data availability. In this article, we utilize census costs and earnings data to examine operational characteristics and economic outcomes for shorebased processors before and after implementation of the West Coast Groundfish Trawl Catch Share Program. While the overall number of buyers of catch share species along the coast decreased and fish input prices generally increased, patterns in outcomes were different for processors with Pacific whiting operations compared to those that produce nonwhiting groundfish, including lengthened seasonal whiting operations but a decrease in the number of days receiving nonwhiting groundfish. These differences in outcomes illustrate the complexities involved in the management of multispecies fisheries with heterogeneous participants in both the harvest and post-harvest sectors. This review contributes to the fairly limited empirical work on the fish processing sector, which is an integral part of the seafood supply chain and important to the economic resilience of coastal fishing communities.     

Modeling and optimizing urban bus transit considering headway variation for cost and service reliability analysis

Due to the stochastic nature of traffic conditions and demand fluctuations, it is a challenging task for operators to maintain reliable services, and passengers often suffer from longer travel times. A failure to consider this issue while planning bus services may lead to undesirable results, such as higher costs and a deterioration in level of service. Considering headway variation at route stops, this paper develops a mathematical model to optimize bus stops and dispatching headways that minimize total cost, consisting of both user and operator costs. A Genetic Algorithm is applied to search for a cost-effective solution in a real-world case study of a bus transit system, which improves service reliability in terms of a reduced coefficient of variation of headway.     

Environmental risk evaluation criteria

This paper describes an approach to incorporating environmental risk evaluation criteria within IMO’s guidelines for Formal Safety Assessment (FSA). Such criteria are currently absent from FSA, and the discussion to include them has just started. Said criteria are relevant for evaluating on a cost-benefit basis Risk Control Options (RCOs) for reducing oil spill pollution risk. Oil pollution may comefrom any ship, including bunker spills from non-tank vessels. RCOs are not necessarily ship-based, and may include vessel traffic management information systems (VTMIS) and other options. The proposed approach may be useful in extending FSA to cover environmental risk evaluation criteria and combines such criteria with criteria already in use in FSA. It can also readily be extended to environmental consequences other than oil pollution. Recent IMO developments on this matter are also reported.     

Inertial waves in the Ibiza channel

Currentmeter data taken in the Ibiza Channel show the almost permanent presence of near-inertial motions below the mixed layer. They correspond to downwards progressing waves with a vertical group velocity of some m/day. The presence of the Balearic Front sensibly affects the propagation of these inertial waves. Although situations exist in which the passage of atmospheric fronts along the Channel is clearly the generating force of these near-inertial motions we find others in which the energy density in mid-depths is higher than in any other depth. These last situations are closely related to the arrival to the Channel of some of the different water masses which flow around there. A clear correspondence between the presence of relatively strong inertial waves and a noticeable vertical shear of the subinertial flow, evidenced by an averaged Richardson number, is also observed. In some circumstances, the vertical shear of the whole flow (inertial plus subinertial) is higher than the stability limit, that is, Ri < 0.25, favoring the braking of the internal waves. This could be a plausible cause of their decay and a reason to explain why they do not penetrate further than certain depths.     

Four-wheel vehicle kinematic and geometric constraints for definition of tire slip angle

When considering vehicle safety, tires and all that they represent are a fundamental topic. Tire studies have received a considerable amount of attention from the research community because their improvement has a direct and strong impact on vehicle handling and braking. Within this eld of analysis lies an important behavioral feature: the tire slip angle, which is a consequence of lateral forces acting on the tire. This characteristic is predicted in some cases and evaluated experimentally in others. This paper addresses another way to assess the slip angle. We propose a mathematical model that describes a constraint linking the slip angle and steering angle that make a vehicle turn. We present a simplied kinematic model (based on the classic bicycle model) and a four-wheel model, which makes all of the angles involved compatible with each other. In our case, the match will be given by the determination of the turning radius. Two different scenarios, understeering and oversteering vehicles, were simulated, and the results and conclusions reached are presented herein.     

Transport planning and the policy-modelling interface

Evidence of the inability of transport models to elucidate policy is cited and reasons for this weakness are then suggested.Attention is drawn to the fundamental changes in both opinion and policy currently taking place. There is less concern with accessibility per se and rather more concern with the provision of adequate or minimum accessibility for certain social groups. More emphasis is placed also on the environmental aspects of transportation.The implications of these changes are outlined. It is not at all clear that the need to adapt and up-date models is appreciated widely enough. Finally, it is considered whether fundamental changes in methodology may help to make transport models more responsive to policy needs.     

Analytical Tire Models for Dynamic Vehicle Simulation

Four basic tire models suitable for dynamic vehicle simulation are formulated. The models are compared through a six-degree-of-freedom nonlinear simulation of a cargo truck crossing rough ground. Guidelines are developed for the selection of an optimum tire model for a given dynamic vehicle simulation.