We study Z2 orbifolds of M-theory in terms of E10. We find a simple relation between the Z2 action on E10 and the imaginary root that corresponds [hep-th/0401053] to the "twisted sector" branes. We discuss the connection between the Kac-Moody algebra DE10 and the "untwisted" sector, and we demonstrate how DE18 can describe both the untwisted and twisted sectors simultaneously.
For sixty years, engineers and planners have debated the freeway’s role in the city. Engineers have tended to view freeways strictly in traffic service terms. Planners, on the other hand, have long viewed freeways not only as a means of facilitating automobile transportation but also as a tool for reshaping the city. This paper uses the plans of Harland Bartholomew and Robert Moses to illustrate these competing visions of the freeway. In the end, the traffic-service vision of the engineers emerged victorious as a result of state and federal highway finance decisions, and this victory has carried with it a high price for many American cities.
Since the passage of the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, federal surface transportation legislation has mandated that state departments of transportation (DOTs) engage in increasingly collaborative and multi-modal transportation planning. Over the past decade state DOTs have had to reassess both their role in and approach to statewide transportation planning. Such reassessments, by their very nature, require one to consider pre-ISTEA (and TEA-21) planning efforts by state DOTs. What have been the driving forces – both issues and interest groups – shaping state transportation policy and how have they evolved over time? Reexamining the past allows us to look at the specific agency responses to these forces – both successes and failures – and offers lessons on the appropriate planning role for state-level transportation agencies.
This paper considers the experiences of the California Department of Transportation (Caltrans) and its predecessor agencies in addressing the task of statewide transportation planning in California. The paper begins with the early efforts of the Bureau of Highways, in tandem with an array of good roads movement activists, to create the state highway system for California, and the paper ends in the present-day with its debates over the proper roles of state versus regional and local governments in transportation planning. The historical discussion is divided into eras of statewide transportation planning, with each era focused on a particular policy or planning issue or set of issues. The paper concludes with general observations on the themes and lessons suggested by the state’s experiences.
State DOT's are grappling with how to meet federal mandates that they engage in multimodal transportation planning with metropolitan planning organizations and other governmental agencies. The experience of one state, California, shows that the recent round of soul-searching is nothing new. California's experience is one of episodic, triage-style planning undertaking in response to a recurring series of fiscal or physical crises and external mandates. The only exception to this pattern was the long-range planning surrounding the California Freeway System plan adopted in 1959. But given today's transportation policy environment and prevailing public attitudes abut building large transportation facilities, the ability of state DOTs to craft far-reaching, long-range plans along the lines of the 1959 example is a Herculean task. Today's round of organizational soul-searching could represent the first hesitant steps towards an era of thoughtful, proactive planning, or it could simply be the latest example of reactive planning. Past experience suggests that the latter is more likely the case.
Eleven dimensional supergravity compactified on $T^10$ admits classical solutions describing what is known as billiard cosmology - a dynamics expressible as an abstract (billiard) ball moving in the 10-dimensional root space of the infinite dimensional Lie algebra E10, occasionally bouncing off walls in that space. Unlike finite dimensional Lie algebras, E10 has negative and zero norm roots, in addition to the positive norm roots. The walls above are related to physical fluxes that, in turn, are related to positive norm roots (called real roots) of E10. We propose that zero and negative norm roots, called imaginary roots, are related to physical branes. Adding 'matter' to the billiard cosmology corresponds to adding potential terms associated to imaginary roots. The, as yet, mysterious relation between E10 and M-theory on $T^10$ can now be expanded as follows: real roots correspond to fluxes or instantons, and imaginary roots correspond to particles and branes (in the cases we checked). Interactions between fluxes and branes and between branes and branes are classified according to the inner product of the corresponding roots (again in the cases we checked). We conclude with a discussion of an effective Hamiltonian description that captures some features of M-theory on $T^10.$
In 2003, the federal government spent about $37 billion on the highway and transit networks that comprise the surface transportation system. With so much money at stake it is no surprise that expenditure decisions are subject to intense debate. Settling past conflicts has required the development of elaborate compromises, from the transit penny in 1982 to minimum-guaranteed-return rules in more recent years. Conflicts over expenditure decisions continue to resurface, particularly during the debates over program reauthorization.
This dissertation examines federal surface transportation expenditure policy. It includes both historical and quantitative analyses. The historical analysis seeks to understand how the current expenditure policy rules came into being and how they have evolved from the 1890’s to the present. The quantitative analysis focuses on the period from 1990 to the present. It examines the spatial pattern of highway and transit expenditures among the states, investigates geographic redistribution in the highway program (the donor state conflict), and determines whether these expenditure patterns can be explained by political, transportation, and socio-demographic variables. It also seeks to understand whether these patterns have changed in the years following passage of ISTEA and TEA-21.
The historical analysis shows that political and/or institutional inertia has limited the opportunity for significant policy change. Policies developed to address particular problems at very specific moments in time have been retained long after their original rationales have disappeared. The Senate has traditionally defended the policy status quo, and its institutional structure has been an important factor in the development of federal policy. The quantitative analysis shows that the relationships between highway expenditures and highway use and between transit expenditures and transit use are moving in opposite directions. The geographic redistribution of federal highway dollars is unrelated to either the use or extent of a state’s highway system. The analysis also shows that a state’s earmark dollars are more closely related to political representation variables than are its formula dollars. Notwithstanding the rhetoric of policy change, ISTEA and TEA-21 have produced only modest changes in any of these patterns.
The first thing to understand about transportation in California is how grave the problems really are. In terms of both traffic congestion and air pollution, California’s problems are the worst in the nation. Traffic congestion is difficult to comparea mongci ties, but one attempt to rank Americanc ities in terms of their traffic congestion found that Los Angeles is number1 , San Francisco-Oaklandi s number3 , and San Bemardino-R/versidea hd San Diego tie for number8 . Addedt ravel time and added fuel consumptiona ssociated with reduceds peeds in congestedt raffic are estimatedt o cost motorists in these four cities a total of $13 billion a year. Ninety percent of this cost is for the added travel time and 10 percent is for the added fuel consumptionc aused by delays in peak-hour traffic) To put this $13- billion-a-year cost estimate in perspective, the total general revenue (property taxes, sales taxes, business license taxes, etc.) of all c2ities in Califomiaw as $9.4 billion in 1994-1995. Therefore, the estimated costs of traffic congestion in Los Angeles, San Francisco-Oakland, San Bemardino-R/verside, and San Diego alone are 38 percent more than the general revenues of all municipal governments in California combined.
Universities and public transit agencies in the United States have together invented an arrangement – called Unlimited Access – that provides fare-free transit service for all students (and, on some campuses, faculty and staff as well). Unlimited Access is not free transit but is instead a new way to pay for it. The university pays the transit agency for all rides taken by eligible members of the campus community. This article evaluates the results of the Unlimited Access program at the University of California, Los Angeles (UCLA). Bus ridership for commuting to campus increased by 56 percent during BruinGO’s first year, and solo driving fell by 20 percent. Because these startling results were achieved in a city famous for its addiction to cars, they suggest that Unlimited Access can succeed almost anywhere.
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