Towed-Diver Surveys,a Method for Mesoscale Spatial Assessment of Benthic Reef Habitat: A Case Study at Midway Atoll in the Hawaiian Archipelago

An integrated method for benthic habitat assessment is described, in which divers maneuver boards equipped with digital video, temperature, and depth recorders while being towed behind a small boat. The tow path is concurrently recorded by a GPS receiver, and a layback model is applied to more accurately map the data. Percent cover of salient benthic categories is quantified by whole-image analysis of still frames sampled at 30-s intervals. The results of 15 towed-diver surveys at Midway Atoll in the Hawaiian Archipelago during a mass coral bleaching event are presented to exemplify the method and are compared to results derived from conventional methods. Towed-diver surveys bridge a gap between large-scale mapping efforts using satellite data and small-scale, roving diver assessments, providing a mesoscale spatial assessment of reef habitats. The spatial coverage of towed-diver surveys provides comprehensive data to managers concerning the extent, intensity, differential taxonomic response, and bathymetric correlates of bleaching.     

Distribution of drifting seaweeds in eastern East China Sea

In offshore waters with relatively low primary production, drifting seaweeds composed of Sargassum species form an identical ecosystem such as an oasis in desert. Commercially important pelagic fishes such as jack mackerel (Trachurus japonicus) and yellow tail (Seriola quinqueradiata) spawn in East China Sea pass their juvenile period accompanying drifting seaweeds. Therefore drifting seaweeds are very important not only in offshore ecosystem but also fishery resources. However the distribution of drifting seaweeds in East China Sea has scarcely known. Then we conducted two research cruises of R/V Hakuho–Maru in May 2002 and in March 2004. During the cruises, drifting seaweeds were visually observed from the bridge and sampled with a towing net. The observation revealed that the drifting seaweeds were distributed along the front between the Kuroshio Current and coastal waters and mainly composed of one seaweed species, Sargassum horneri (Turner) C. Agardh from spring to early summer. There are no reports on geographical distribution of this species in the coasts south of southern Kyushu Island in Japan. Kuroshio Current flows northeastward there. Buoys with GPS attached to drifting seaweeds released off Zhejiang Province, China, in March 2005 to track their transport. Their positions monitored by ORBCOM satellite showed that they were transported to the area in East China Sea, where the drifting seaweeds were observed during the cruises, in 2 months. These facts suggest that S. horneri detached from Chinese coast in March or months earlier than March could be transported to fringe area of continental shelf and waters influenced by Kuroshio Current from March to May. Therefore the Sargassum forests, especially S. horneri, along the Chinese coast play a very important role in the ecosystem of the East China Sea as a source of drifting seaweeds.     

BOOK REVIEW

Abstract

Nationwide Transport Surveys and Time‐Use Surveys both reflect the daily agendas and schedules of the reporting individuals and should therefore yield comparable indicators of travel behaviour; for instance: immobility rate (share of persons not leaving the home on any one day), daily travel time, and number of trips per day. These two surveys exist in three countries from the same time period: Belgium, France, Great Britain. The comparisons demonstrate that they tell parallel stories, but that the levels of the variables are significantly different with lower immobility rates and longer travel times reported in the Time‐Use Surveys. These surveys should therefore be integrated in the analysis of travel behaviour analysis as a crucial yardstick. In Europe, where Nationwide Travel Surveys are intermittent and not harmonized, the harmonised Time‐Use Surveys allow for crucial European‐wide comparisions across time and space.     

Ship complexity assessment at the concept design stage

An innovative complexity metric is introduced that provides a way to compare similar or different ship types and sizes at the contract design stage. The goal is to provide the designer with this information throughout the design process so that an efficient design is obtained during the first design run. Application to and validation on real passenger ships indicate that there is a significant correlation between the error in an engineer’s judgement of complexity and the cost assessment error. It follows that this tool could be used to improve knowledge of the ship’s complexity at the contract design stage, and even to try to optimise the design if the complexity criteria are not fixed by the shipowners.     

The estimation of transport cost functions: a methodological review

Abstract

The ex‐post facto cost of using private finance in roads is examined using a case study approach. The paper focuses on the first eight design, build, finance and operate (DBFO) roads commissioned by the UK Government’s Highways Agency and paid for through a system of shadow tolls. It carries out a financial analysis of the publicly available accounting information from the Highways Agency and its private sector partners for the first 6 years since the start of the 30‐year schemes in 1997. Publicly available financial information about the schemes was found to be limited and opaque. In 3 years, the Highways Agency had paid more than the construction cost. It was unclear whether the payments were higher than expected at financial close. Its private sector partners reported a post‐tax return on capital of 29% and an effective cost of capital of 11% in 2002, twice the cost of public finance. However, operating through a complex web of subcontracting creates additional, undisclosed sources of profit for their parent companies that make it difficult to establish the total cost of using private finance. The paper questions the wisdom of using private finance by providing evidence about the cost, including the cost of risk transfer.     

The VOCO multi-body software in the context of real-time simulation

The railway multi-body software developed for more than 20 years by INRETS (now IFSTTAR), under the name VOCO^®, has been dedicated from the origin to highly nonlinear elements, such as the dry friction dampers of freight bogies and the wheel–rail contact based on measured profiles. A second important step has been the discovery of a particular method in order to simulate on sinuous tracks. In the aim of industrial applications, the specification has always been to reach the goal of real time. Although it is not possible in all the cases, the recent non-Hertzian contact development is allowing real-time simulation to be achieved.     

A review of recent theoretical and empirical analyses of asymmetric information in road safety and automobile insurance

Road safety policies and automobile insurance contracts often use incentive mechanisms based on traffic violations and accidents to promote safe driving. Can these mechanisms improve road safety efficiently? Do they reduce asymmetric information between drivers and insurers and regulators? In other words, is there residual asymmetric information in observed distributions of accidents and infractions? We answer these questions in this article by reviewing recent theoretical and empirical results that rest on various data and methodologies. We present recent tests related to the identification of residual asymmetric information in road safety management and in automobile insurance contracting. We also propose a theoretical analysis of the foundations of point-record driver's licenses observed around the world.     

Noisy demand and mode choice

Mode choice under stochastically varying demand is studied via a dynamic mathematical model which describes the behavioural interactions between population groups. The model is developed by assuming competing attractivity functions for automobile and public transit which motivate their use subject to an overall demand for transportation. When this demand is allowed to vary stochastically, a set of stochastic differential equations describing the model are obtained. These are solved for their steady-state values. It is found that noisy demand can structure the system qualitatively differently than when the demand is fixed. The noise is found to generally reduce the level of public transit ridership, but it also changes the values of the threshold at which new regimes occur and, most interestingly, it induces new steady-state solutions for ridership at critical values of the variance of demand. In the latter case, noise becomes a source of new possibilities in the system by triggering a steady-state solution not present in the noise-free environment.