Railroads represent one of the most efficient methods of long-haul transport for bulk commodities, from coal to agricultural products. Over the past 50 years, the rail network has contracted while tonnage has increased. Service, geographically, has been abandoned along short-haul routes and increased along major long-haul routes, resulting in a network that is more streamlined. The current rail network may be very vulnerable to disruptions, like the failure of a trestle. This paper proposes a framework to model rail network vulnerability and gives an application of this modeling framework in analyzing rail network vulnerability for the State of Washington. It concludes with a number of policy-related issues that need to be addressed in order to identify, plan, and mitigate the risks associated with the sudden loss of a bridge or trestle. Copyright (c) 2008 Copyright the Authors. Journal compilation (c) 2008 Wiley Periodicals, Inc..

Prior analysis regarding transportation infrastructure has often focused on the aggregate effects of public investment on economic growth or activity, usually at a national or state level. Modeling efforts that attempt to treat all counties as equivalent units, while assuming a homogeneous modeling structure for all the units, may miss important information regarding the statistical and causal relationships between economic activity and transportation infrastructure. This study examines the interrelationships between infrastructure and activity using two Washington State highway infrastructure datasets in combination with county-level employment, wages, and establishment numbers for several industrial sectors for a subset of counties from 1990 to 2004. Estimates using vector autoregressions, error correction models, and directed acyclic graphs are made. The results show that the relationships between infrastructure investment and economic activity are often weak and are not uniform in effect.

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Much research in educational psychology concerns group differences. In this study, we argue that Bayesian estimation is more appropriate for testing group differences than is the traditional null hypothesis significance testing (NHST). We demonstrate the use of Bayesian estimation on gender differences in students' achievement goals. Research findings on gender differences in achievement goals have been mixed. We explain how Bayesian estimation of mean differences is more intuitive, informative, and coherent in comparison with NHST, how it overcomes structural and interpretive problems of NHST, and how it offers a way to achieve cumulative progress toward increasing precision in estimating gender differences in achievement goals. We provide an empirical demonstration by comparing a Bayesian and a traditional NHST analysis of gender differences in achievement goals among 442 7 th-grade students (223 girls and 219 boys). Whereas findings from the two analyses indicate comparable results of higher endorsement of mastery goals among girls and higher endorsement of performance-approach and avoidance goals among boys, it is the Bayesian analysis rather than the NHST that is more intuitively interpreted. We conclude by discussing the perceived disadvantages of Bayesian estimation, and some ways in which a consideration of Bayesian probability can aid interpretations of traditional analytical methods.

Students' relationships with mathematics continuously remain problematic, and researchers have begun to look at this issue through the lens of identity. In this article, the researchers discuss identity in education research, specifically in mathematics classrooms, and break down the various perspective on identity. A review of recent literature that explicitly invokes identity as a construct in intervention studies is presented, with a devoted attention to research on identity interventions in mathematics classrooms categorized based on the various perspectives of identity. Across perspectives, the review demonstrates that mathematics identities motivate action and that mathematics educators can influence students' mathematical identities. The purpose of this paper is to help readers, researchers, and educators understand the various perspectives on identity, understand that identity can be influenced, and learn how researchers and educators have thus far, and continue to study identity interventions in mathematics classrooms.