Dispersal of Calluna vulgaris(L.) Hull. seeds on a severly burnt upland moorland

From natural and manipulated experiments at 460 m a.s.l., traps were used to record the dispersal range of Calluna vulgaris seeds on an unvegetated post-wildfire site. Seeds were trapped to 50 m from source, although most (73%) were deposited within one metre of the parent plant. C. vulgaris seeds were not dispersed as far in these experiments as recorded in previous workers’ experiments on lowland grassland

Energy Tax Credits and Residential Conservation Investment

We model the decision to invest in residential energy conservation capital as an irreversible investment in the face of price uncertainty. The irreversible nature of this investment means that there is a value to waiting to invest (an option value) which helps explain the low rate of conservation investment as a result of the residential energy tax credit. Simulations suggest that a tax credit of the type implemented from 1978 through 1985 will not increase conservation investment significantly. We investigate the empirical evidence on the effectiveness of credits using data from a panel data set of roughly 38,000 individual tax returns followed over a three year period from 1979-1981. Unlike previous work, we find that the energy tax credit is statistically significant in explaining the probability of investing. Our estimates suggest that increasing the federal credit by 10 percentage points would increase the percentage of households claiming the credit from 5.7% to 7.1%.

The Incidence of a U.S. Carbon Tax: A Lifetime and Regional Analysis

This paper measures the direct and indirect incidence of a carbon tax using current income and two measures of lifetime income to rank households. OUr results suggest that carbon taxes are more regressive when annual income is used as a measure of economic welfare that when proxies for lifetime income are used. Further, the direct component of the tax, in any given year, is significantly more regressive than the indirect component. In fact, for 1987, the indirect component of the tax is mildly progressive. We observe a modest shift over time with the direct component of carbon taxes becoming less regressive and the indirect component becoming more regressive. These effects mostly offset each other and the distribution of the total tax burden has not changed much over time. In addition we find that regional variation has fluctuated over the years of our analysis. By 2003 there is little systematic variation in carbon tax burdens across regions of the country.

Imperfect Construction of Microclusters

Microclusters are the basic building blocks used to construct cluster states capable of supporting fault-tolerant quantum computation. In this paper, we explore the consequences of errors on microcluster construction using two error models. To quantify the effect of the errors we calculate the fidelity of the constructed microclusters and the fidelity with which two such microclusters can be fused together. Such simulations are vital for gauging the capability of an experimental system to achieve fault tolerance.Comment: 5 pages 2 figure

Distributional Impacts in a Comprehensive Climate Policy Package

This paper provides a simple analytic approach for measuring the burden of carbon pricing that does not require sophisticated and numerically intensive economic models but which is not limited to restrictive assumptions of forward shifting of carbon prices. We also show how to adjust for the capital income bias contained in the Consumer Expenditure Survey, a bias towards regressivity in carbon pricing due to underreporting of capital income in higher income deciles in the Survey. Many distributional analyses of carbon pricing focus on the uses-side incidence of carbon pricing. This is the differential burden resulting from heterogeneity in consumption across households. Once one allows for sources-side incidence (i.e. differential impacts of changes in real factor prices), carbon policies look more progressive. Perhaps more important than the findings from any one scenario, our results on the progressivity of the leading cap and trade proposals are robust to the assumptions made on the relative importance of uses and sources side heterogeneity.

Investigation into Contact Resistance and Damage of Metal Contacts Used in RF-MEMS Switches

This research examines the physical and electrical processes involved in lifecycle failure of Microelectromechanical (MEMS) Radio-Frequency (RF) cantilever beam ohmic contact switches. Failures of these switches generally occur at the contact, but complete details of performance of microcontacts are difficult to measure and have not been previously reported. This study investigated the mechanics of microcontact behavior by designing and constructing a novel experimental setup. Three representative contact materials of varying microstructure (Au, Au5%Ru, Au4%V2O5) were tested and parameters of contact during cycling were measured. The Au4%V2O5, a dispersion strengthened material developed at Lehigh University, showed the most promise of the materials tested with the longest-life contact lasting more than 15.5 x 106 cycles. Evidence of time-dependent deformation and contact heating during cycling was noted in all materials tested. Material hardness was not proportional to contact lifetime or adhesive forces measured during testing. Surfaces of post-cycling contact surfaces were evaluated and failures were categorized by ductile or brittle separation characteristics. Separation characteristics were correlated by contact lifetime

The Incidence of a U.S. Carbon Tax: A Lifetime and Regional Analysis

This paper measures the direct and indirect incidence of a carbon tax using current income and two measures of lifetime income to rank households. Our results suggest that carbon taxes are more regressive when annual income is used as a measure of economic welfare than when proxies for lifetime income are used. Further, the direct component of the tax, in any given year, is significantly more regressive than the indirect component. In fact, for 1987, the indirect component of the tax is mildly progressive. We observe a modest shift over time with the direct component of carbon taxes becoming less regressive and the indirect component becoming more regressive. These effects mostly offset each other and the distribution of the total tax burden has not changed much over time. In addition we find that regional variation has fluctuated over the years of our anlaysis. By 2003 there is little systematic variation in carbon tax burdens across regions of the country.