Assessment of Vulnerability and Integrated Management of Coastal Dunes in Veracruz,Mexico

Dune systems are essential to the ecological balance and sediment inputs of coastal environments and they provide numerous environmental services; however, their existence is threatened by natural and human stressors that contribute to their degradation. Future impacts are expected to be greater because of global climate change in association with further rises in sea level. Beaches and dune systems occupy large areas along the coastline of the state of Veracruz on the Gulf of Mexico. The aim of this study is to establish the intrinsic vulnerability of nine dune fields in Veracruz to current and future impacts and to assess their integrated management status. These dune–beach systems are more vulnerable to the effects of economic activities and land use change than to those induced by natural forces. Results show that six of these dune systems have medium vulnerability and an ecological conservation policy should be adopted; the other three, with high or very high vulnerability, are candidates for a restoration policy.     

The authors in this issue

This paper analyses the impacts on a particular region of a recent policy change regarding public transit subsidy in New Zealand, under which the contributions of local authorities are increased from 0 to 50% of net direct expenditures. The options open to the community are examined and their effects on regional income, future development and social equitability are analysed. It also illustrates the cost effectiveness of a natural monopoly under increased accountability.     

Competition for the German regional rail passenger market 5 years after regionalization

The paper investigates the competition for regional passenger rail services in Germany from 1996 to 2000 by using data mainly provided by regional authorities. It analyses data on the level of network characteristics, contract life, the Länder (i.e. regions), competitive placing procedures, and their winners as well as achieved cost and services improvements. It finds that with competition being rare, the amount of competitively placed services declined until recently. Only about half of the regional authorities gained experience with competitive placings, which points at the expertise deficit of these bodies. A diverse picture on competitive placings' characteristics such as network size and contract life appears. State-owned carrier DB AG remains the dominant player as it could win the majority of the competitively procured services. Private companies have played a minor role in the game up to now. Accomplished reduction of subsidies and improved service quality respectively provide an indication of the potential for enhancing efficiency in this market.     

Ludwig?s Ratchet and the Collapse of New England Groundfish Stocks

The stocks of principal groundfish species off New England have collapsed, creating economic hardship and dislocation in fishing communities from Rhode Island to Maine. In this article we analyze the causes of this collapse using the ?ratchet effect? described by Ludwig, Hilborn, and Walters (1993) as a framework. According to Ludwig, Hilborn, and Walters, powerful economic and political interests drive fisheries to overcapitalize and overexploit despite scientific evidence that stocks are declining. When the fishery is no longer economically viable, governments provide financial assistance to minimize economic hardship. When stocks increase there is another rush to invest, and the cycle repeats itself. The history of groundfish management in New England conforms well to this model. Optimism among fishers and government over U.S. control of this fishery in 1977 stimulated successive rounds of investment that built up excessive fishing capacity despite warnings from scientists that stocks were becoming weaker. Management regimes designed by the New England Fishery Management Council were ineffective in constraining fishing effort. Collapse of the stocks has led to severe restrictions on fishing and to government assistance. We suggest that the integration of science, management, and harvesting sectors through ecosystem-based management offers the best means of avoiding similar situations in the future.     

A GIS‐based traffic analysis zone design: implementation and evaluation

The purpose of this paper is to implement an efficient method for GIS‐based traffic analysis zone (TAZ) design in order to evaluate and validate such a method. The method was developed by the authors.

Moran's I spatial autocorrelation coefficient and sample variance are used for evaluating the generated TAZs using the Champaign‐Urbana, IL region as a case study. Sensitivity analysis is also conducted to explore the fluctuations in TAZ generation outcomes. The evaluation, the validation as well as the TAZ design have been implemented with ARC/INFO GIS software on a UNIX workstation platform.     

Assessing land‐use regulations in coastal wetlands: The case of the long point area,lake Erie,Ontario

Abstract

The first comprehensive attempt at development control along the Canadian Great Lakes shoreline was the 1976 lakeshore regulation policy adopted by the Regional Municipality of Haldimand‐Norfolk on the north Lake Erie shore. This innovative strategy was initiated at the municipal level as a component of the regional land‐use planning process. Determination of efficiency and effectiveness of the policy implementation process is based on analysis of permit approval files. All development applications submitted between 1976 and 1980 in the Turkey Point and Long Point Peninsulas are evaluated. Those areas, the most popular cottaging areas in the region, are most susceptible to flood and erosion hazards. Of the total applications submitted during the four‐year study period, 37 percent were in these areas. The policy was ineffective and inefficient in controlling development in the two peninsulas. Applications were approved in the majority of cases, despite regulatory prohibition of developments in hazard‐susceptible areas. There were lengthy decision‐making delays, often exceeding one year, and frequent violations of regulatory procedures. Recommendations are suggested to improve policy implementation.     

Changing patterns of urban travel Part 2. public transport and future patterns of travel

This two‐part paper contains most of a report prepared by TRRL for the European Conference of Ministers of Transport, and presented by one of the authors to the Council of Ministers in November 1984. Part 1, which was published in the January‐March 1986 issue of Transport Reviews, looked at the way cities have been changing over the years and the influence of growing car ownership on trip patterns. This part examines the changes in public transport use in more detail, considers the interactions between the various underlying trends, speculates on future travel patterns by both public and private means and considers the likely impact of land use and transport policies.     

Proximité aux infrastructures et croissance de l’emploi en ?le-de-France (1993–2008) : le r?le des transports à l’échelle intramétropolitaine

This article aims to analyze the role of proximity to transport infrastructures in employment growth within 291 municipalities located in the ?le-de-France region between 1993 and 2008. Based on the employment data from Unistatis, a multiple regression econometric model is estimated, first without variables describing proximity to infrastructure, and then integrating them in order to measure the gain in explanatory power. The results suggest that the role of infrastructure in employment growth rate is limited and varies according to economic sectors and network types.     

Hybrid modeling of seat-cab coupled system for truck

For the complex structure and vibration characteristics of the seat and cab system of truck, there is no reliable theoretical model for the suspensions design at present, which seriously restricts the improvement of ride comfort. In this paper, a 4 degree-of-freedom seat-cab coupled system model was presented; using the mechanism modeling method, its vibration equations were built; then, by the tested cab suspensions excitations and seat acceleration response, its parameters identification mathematical model was established. Combining the tested signals and a simulation model with the parameters identification mathematical model, a new method of hybrid modeling of seat-cab coupled system was presented. With a practical example of seat and cab system, the parameters values were identified and validated by simulation and test. The results show that the model and method proposed are correct and reliable, and lay a good foundation for the optimal design of seat suspension and cab suspensions to improve ride comfort.