Late-time Kerr tails: generic and non-generic initial data sets, "up" modes, and superposition

Three interrelated questions concerning Kerr spacetime late-time scalar-field tails are considered numerically, specifically the evolutions of generic and non-generic initial data sets, the excitation of "up" modes, and the resolution of an apparent paradox related to the superposition principle. We propose to generalize the Barack-Ori formula for the decay rate of any tail multipole given a generic initial data set, to the contribution of any initial multipole mode. Our proposal leads to a much simpler expression for the late-time power law index. Specifically, we propose that the late-time decay rate of the $Y_{\ell m}$ spherical harmonic multipole moment because of an initial $Y_{\ell' m}$ multipole is independent of the azimuthal number $m$, and is given by $t^{-n}$, where $n=\ell'+\ell+1$ for $\ell<\ell'$ and $n=\ell'+\ell+3$ for $\ell\ge\ell'$. We also show explicitly that the angular symmetry group of a multipole does not determine its late-time decay rate.Comment: 12 pages, 13 figures, 4 tables. Substantially revised manuscrip

Accurate time-domain gravitational waveforms for extreme-mass-ratio binaries

The accuracy of time-domain solutions of the inhomogeneous Teukolsky equation is improved significantly. Comparing energy fluxes in gravitational waves with highly accurate frequency-domain results for circular equatorial orbits in Schwarzschild and Kerr, we find agreement to within 1% or better, which we believe can be even further improved. We apply our method to orbits for which frequency-domain calculations have a relative disadvantage, specifically high-eccentricity (elliptical and parabolic) "zoom-whirl" orbits, and find the energy fluxes, waveforms, and characteristic strain in gravitational waves.Comment: 6 pages, 9 figures, 2 tables; Changes: some errors corrected. Comparison with Frequency-domain now done in stronger fiel

Method of producing high T(subc) superconducting NBN films

Thin films of niobium nitride with high superconducting temperature (T sub c) of 15.7 K are deposited on substrates held at room temperature (approx 90 C) by heat sink throughout the sputtering process. Films deposited at P sub Ar 12.9 + or - 0.2 mTorr exhibit higher T sub c with increasing P sub N2,I with the highest T sub c achieved at P sub n2,I= 3.7 + or - 0.2 mTorr and total sputtering pressure P sub tot = 16.6 + or - 0.4. Further increase of N2 injection starts decreasing T sub c

EVALUATING THE COST EFFECTIVENESS OF LAND RETIREMENT PROGRAMS

This paper extends an integrated framework that combines economic, environmental and GIS modeling to evaluate the cost effectiveness of land retirement programs. The modeling framework is applied to the Lower Sangamon Watershed in Cass County of Illinois to examine the economic costs and environmental benefits of three land retirement scenarios: land actually enrolled in the Illinois CREP, land selected by a land rental cap mechanism and land identified by a least cost model. We find that land retirement in the watershed successfully achieved the program goal of 20% sediment abatement. However, in achieving the same level of sediment abatement, the costs of actual land retirement are 1.3 times and 2.1 times of those in a land rental cap mechanism and a least cost model respectively. The model results also reveal that cost effective land retirement parcels are more sloping, close to river, with higher upland sediment inflow, more on-site erosion and lower quasi-rents. The results indicate that governments may improve the cost effectiveness of land retirement program through targeting. And there is a need to modify current Illinois CREP eligibility criteria to include sloping cropland adjacent to the river in the program. Furthermore our results suggest that in the program implementation land retirement contracts could be selected based on several measurable parameters such as distance from the river and slope.Land Economics/Use,

OPTIMAL TARGETING OF CREP TO IMPROVE WATER QUALITY: DETERMINING LAND RENTAL OFFERS WITH ENDOGENOUS SEDIMENT DEPOSITION COEFFICIENTS

An integrated watershed management framework that combines detailed spatial biophysical attributes of land with a hydrologic model and an economic model is developed to study the cost-effective enrollment of land in the Conservation Reserve Enhancement Program (CREP). Compared with previous related studies that assumed exogenous sediment deposition coefficients related only to site specific characteristics, this research explicitly considers endogenous sediment deposition coefficients, that are determined by landuse decisions made by all land parcels in the run-off path, in determining land rental offers. The modeling framework is applied to one of the eligible watersheds, Court Creek, in Illinois. We find that the optimal targeting of land enrollment is much more cost-effective than a uniform land rental policy.Land Economics/Use, Resource /Energy Economics and Policy,

The Deuteron Spin Structure Functions in the Bethe-Salpeter Approach and the Extraction of the Neutron Structure Function g1n(x)g_1^n(x)

The nuclear effects in the spin-dependent structure functions $g_1^D$ and $b_2^D$ are calculated in the relativistic approach based on the Bethe-Salpeter equation with a realistic meson-exchange potential. The results of calculations are compared with the non-relativistic calculations. The problem of extraction of the neutron spin structure function, $g_1^n$, from the deuteron data is discussed.Comment: (Talk given at the SPIN'94 International Symposium, September 15-22, 1994, Bloomington, Indiana), 6 pages, 5 figures, Preprint Alberta Thy 29-9

The Corporate Monitor: The New Corporate Czar?

Following the recent spate of corporate scandals, government enforcement authorities have increasingly relied upon corporate monitors to help ensure law compliance and reduce the number of future violations. These monitors also permit enforcement authorities, such as the Securities & Exchange Commission and others, to leverage their enforcement resources in overseeing corporate behavior. However there are few descriptive or normative analyses of the role and scope of corporate monitors. This paper provides such an analysis. After sketching out the historical development of corporate monitors, the paper examines the most common features of the current set of monitor appointments supplemented by interviews with monitors. This is followed by a normative analysis that examines when it is desirable to appoint monitors and what powers and obligations they should have. Based on this analysis, we provide a number of recommendations for enhancing the potential of corporate monitors to serve a useful deterrent and law enforcement function without being unduly burdensome on corporations. This involves, among other things, discussion of the kinds of powers monitors should have and the fiduciary duties monitors should owe to the shareholders whose businesses they are monitoring

Building stock dynamics and its impacts on materials and energy demand in China

China hosts a large amount of building stocks, which is nearly 50 billion square meters. Moreover, annual new construction is growing fast, representing half of the world's total. The trend is expected to continue through the year 2050. Impressive demand for new residential and commercial construction, relative shorter average building lifetime, and higher material intensities have driven massive domestic production of energy intensive building materials such as cement and steel. This paper developed a bottom-up building stock turnover model to project the growths, retrofits and retirements of China's residential and commercial building floor space from 2010 to 2050. It also applied typical material intensities and energy intensities to estimate building materials demand and energy consumed to produce these building materials. By conducting scenario analyses of building lifetime, it identified significant potentials of building materials and energy demand conservation. This study underscored the importance of addressing building material efficiency, improving building lifetime and quality, and promoting compact urban development to reduce energy and environment consequences in China

The Corporate Monitor: The New Corporate Czar?

Following the recent spate of corporate scandals, government enforcement authorities have increasingly relied upon corporate monitors to help ensure law compliance and reduce the number of future violations. These monitors also permit enforcement authorities, such as the Securities & Exchange Commission and others, to leverage their enforcement resources in overseeing corporate behavior. However there are few descriptive or normative analyses of the role and scope of corporate monitors. This paper provides such an analysis. After sketching out the historical development of corporate monitors, the paper examines the most common features of the current set of monitor appointments supplemented by interviews with monitors. This is followed by a normative analysis that examines when it is desirable to appoint monitors and what powers and obligations they should have. Based on this analysis, we provide a number of recommendations for enhancing the potential of corporate monitors to serve a useful deterrent and law enforcement function without being unduly burdensome on corporations. This involves, among other things, discussion of the kinds of powers monitors should have and the fiduciary duties monitors should owe to the shareholders whose businesses they are monitoring