The NASA Electric Propulsion Program

The NASA OAST Propulsion, Power, and Energy Division supports an electric propulsion program aimed at providing benefits to a broad class of missions. Concepts which have the potential to enable or significantly benefit space exploration and exploitation are identified and advanced toward application in the near and far term. This paper summarizes recent program progress in mission/system analysis; in electrothermal, electrostatic, and electromagnetic propulsion technologies; and in propulsion/spacecraft integration

Real Estate and the Tax Reform Act of 1986

In contrast to the conventional wisdom, real estate activity in the aggregate is not disfavored by the 1986 Tax Act. Within the broad aggregate, however, widely different impacts are to be expected. Regular rental and commercial activity will be slightly disfavored, while historic and old rehabilitation activity will be greatly disfavored. In contrast, owner- occupied housing, far and away the largest component of real estate, is favored, both directly by an interest rate decline and indirectly owing to the increase in rents. Low-income rental housing may be the most favored of all real estate activities. The rent increase for residential properties will be 10 to 15 percent with our assumption of a percentage point decline in interest rates. For commercial properties, the expected rent increase is 5 to 10 percent. The market value decline, which will be greater the longer and further investors think rents will be below the new equilibrium, is unlikely to exceed 4 percent in fast growth markets, even if substantial excess capacity currently exists. In no-growth markets with substantial excess capacity, market values could decline by as much as 8 percent from already depressed levels. Average housing costs will decrease slightly for households with incomes below about $60,000, but increase by 5 percent for those with incomes above twice this level. With the projected increase in rents, homeownership should rise for all income classes, but especially for those with income under$60,000. The aggregate home ownership rate is projected to increase by three percentage points in the long run in response to the Tax Act. The new passive loss limitations are likely to lower significantly the values of recent loss-motivated partnership deals and of properties in areas where the economics have turned sour (vacancy rates have risen sharply). The limitations should have little impact on new construction and market rents, however. Reduced depreciation write-offs, lower interest rates, and higher rents all act to lower expected passive losses. Moreover, financing can be restructured to include equity-kickers or less debt generally at little loss of value.

Understanding the Real Estate Provisions of Tax Reform: Motivation and Impact

Capital investment tax provisions have been changed numerous times in the last decade, with depreciation tax lives shortened in 1981 and lengthened ever since and capital gains taxation reduced in 1978 and 1981 and now increased. The first part of this paper analyzes these changes and attributes a large part of them, including the 1986 Tax Act, to changes in inflation: tax depreciation schedules and capital gains taxation that look reasonable when the tax depreciation base is being eroded at ten percent a year and an overwhelming share of capital gains is pure inflation take on a different appearance when inflation is only four percent. The remainder of the paper critiques the typical project model used to compute impacts of tax changes on real estate and report simulation results using a modified model.

Constructing Gravity Amplitudes from Real Soft and Collinear Factorisation

Soft and collinear factorisations can be used to construct expressions for amplitudes in theories of gravity. We generalise the "half-soft" functions used previously to "soft-lifting" functions and use these to generate tree and one-loop amplitudes. In particular we construct expressions for MHV tree amplitudes and the rational terms in one-loop amplitudes in the specific context of N=4 supergravity. To completely determine the rational terms collinear factorisation must also be used. The rational terms for N=4 have a remarkable diagrammatic interpretation as arising from algebraic link diagrams.Comment: 18 pages, axodraw, Proof of eq. 4.3 adde

THE ECONOMICS OF RIPARIAN MANAGEMENT: A LITERATURE REVIEW

Resource /Energy Economics and Policy,

Incorporating ASP.Net in an Information Systems Curriculum

The challenge of providing information systems graduates with the optimal balance between the old and new technology is a constantly evolving process. This teaching tip introduces Microsoft\u27s ASP.NET technology, which can be used as a bridge to integrate mainframe and client/server technologies. In order to maximize the benefits of using ASP.NET, students need to understand and apply the interrelated concepts of Windows XP professional security system, the Web Server structure, and the .Net Visual Studio setup routine for the development environment

Teleoperator Maneuvering System (TMS) Mission Applications and Benefits

The Teleoperator Maneuvering System (TMS) is a Shuttlelaunched, free-flying, remotely controlled, reusable orbital support vehicle capable of providing a wide range of placement, maneuvering, retrieval, and maintenance/repair user services for future satellites and for large space systems being planned for the late 80\u27s and beyond. The TMS will greatly extend the operating range and altitudes provided by the basic Space Transportation System (STS) in low Earth orbit; similar capabilities are also provided at geosynchronous altitudes when the TMS is delivered to that location with the Centaur or alternative upper stages. Basic TMS capabilities for both long duration and short term orbital missions, including Space Station support operations, will be described. The combined utilitarian, performance, and economic benefits offered to the user community by the TMS program will also be presented