Beltway: Getting Around Garbage Collection Gridlock

We present the design and implementation of a new garbage collection framework that significantly generalizes existing copying collectors. The Beltway framework exploits and separates object age and incrementality. It groups objects in one or more increments on queues called belts, collects belts independently, and collects increments on a belt in first-in-first-out order. We show that Beltway configurations, selected by command line options, act and perform the same as semi-space, generational, and older-first collectors, and encompass all previous copying collectors of which we are aware. The increasing reliance on garbage collected languages such as Java requires that the collector perform well. We show that the generality of Beltway enables us to design and implement new collectors that are robust to variations in heap size and improve total execution time over the best generational copying collectors of which we are aware by up to 40%, and on average by 5 to 10%, for small to moderate heap sizes. New garbage collection algorithms are rare, and yet we define not just one, but a new family of collectors that subsumes previous work. This generality enables us to explore a larger design space and build better collectors

Scaling Dynamics of Domain Walls in the Cubic Anisotropy Model

We have investigated the dynamics of domain walls in the cubic anisotropy model. In this model a global O(N) symmetry is broken to a set of discrete vacua either on the faces, or vertices of a (hyper)cube. We compute the scaling exponents for $2\le N\le 7$ in two dimensions on grids of $2048^2$ points and compare them to the fiducial model of $Z_2$ symmetry breaking. Since the model allows for wall junctions lattice structures are locally stable and modifications to the standard scaling law are possible. However, we find that since there is no scale which sets the distance between walls, the walls appear to evolve toward a self-similar regime with $L\sim t$.Comment: 16 pages, 12 figure

Specific Antibodies to Recombinant Allergens of \u3cem\u3eAspergillus fumigatus\u3c/em\u3e in Cystic Fibrosis Patients with ABPA

Background Aspergillus fumigatus, a widely distributed fungus, has been implicated in causing life threatening infections as well as severe asthma and allergic diseases in man. Allergic affliction like allergic bronchopulmonary aspergillosis (ABPA) is a disabling lung disease frequently seen in patients with asthma and cystic fibrosis. Immunodiagnosis of the former is comparatively easier due to the availability of purified antigens and sensitive methods. However, this is not true with cystic fibrosis patients where the prevalence of ABPA is fairly high and the morbidity and mortality are significant. Methods In the present study, we have evaluated purified recombinant allergens from A. fumigatus, namely Asp f 1, f 2, f 3, f 4, and f 6 using ELISA and a semi-automated method (ImmunoCAP). We studied 17 patients each from cystic fibrosis with ABPA, and cystic fibrosis with asthma, 22 cystic fibrosis with no ABPA or asthma, and 11 age matched controls. Results The results indicate that no antigen, antibody or method is capable of differentiating cystic fibrosis (CF) with ABPA from other CF patients, although some allergens showed strong reaction or showed more prevalence among the patients studied. Conclusion When results of several allergens such as Asp f 1, f 2, f 3, f 4, and f 6 in their binding to IgA, IgG, and IgE antibodies were analyzed, a more strong discrimination of CF patients with ABPA was possible from the other groups studied

Financial Appraisal of the Banks for Cooperatives

This study examines the financial situation of the Farm Credit System Banks for Cooperatives using comparative analysis for the period 1978 through 1991. Profitability and leverage measures of the Banks for Cooperatives are compared with similar measures of large commercial banks. The Banks for Cooperatives were found to have performed as well as large commercial banks. Some differences can be explained as compatible with differences in the goals and objectives of a cooperative versus an investor-owned firm. Most differences can be attributed to the financial strength of the Banks for Cooperatives relative to the commercial banking industry.Agribusiness, Agricultural Finance,

Valuing Catastrophic Citrus Losses

Courts are often required to estimate changes in welfare to agricultural operations from catastrophic events. For example, courts must assign damages in lawsuits, such as with pesticide drift cases, or determine "just compensation" when the government takes private land for public use, as with the removal of dairy farms from environmentally sensitive land or destruction of canker-contaminated citrus trees. In economics, the traditional method of quantifying producer losses is estimating changes in producer welfare, but courts rarely use this method. Instead, they turn to substitute valuation methods that may not fully capture welfare changes, such as changes in land value, tree replacement value, and total revenue. This study examines various measures for valuing the back-to-back catastrophic freezes that occurred in the Florida citrus industry in the 1980s. We first use the traditional method to determine the welfare change due to a freeze (1) for a citrus grove that loses one crop and is able to return to full production the next year, and (2) the lower measure of welfare loss due to a citrus grove that loses all of its trees and is abandoned or is replanted. The lower measure is used to simulate the legal doctrine of avoidable consequences. These measures are then compared to substitute valuation measures that have been used by courts to determine welfare changes. For case 1, total revenue overestimates losses by 35.6%. For case 2, total revenue overestimates losses by 55.3%, tree replacement value underestimates losses by 93.6%, and changes in land value underestimates losses by 13.2%.citrus, perennial crops, catastrophic loss, damages, freeze, Crop Production/Industries,

Valuing Catastrophic Losses for Perennial Agricultural Crops

Courts are often required to estimate changes in welfare to agricultural operations from catastrophic events. For example, courts must assign damages in lawsuits, such as with pesticide drift cases, or determine 'just compensation' when the government takes private land for public use, as with the removal of dairy farms from environmentally sensitive land or destruction of canker-contaminated citrus trees. In economics, the traditional method of estimating changes in producer welfare is the computation of lost producer surplus, but courts rarely use this method. Instead, they turn to substitute valuation methods that may not fully capture welfare change, such as changes in land value, tree replacement value, and total revenue. This study examines various measures for valuing the back-to-back catastrophic freezes that occurred in the Florida citrus industry in the 1980s. We first use the traditional method to determine the welfare change due to a freeze (1) for a citrus grove that loses one crop and is able to return to full production the next year (simulating destruction of annual crops), and (2)the lower measure of welfare loss due to a citrus grove that loses all of its trees and is abandoned or is replanted. The lower measure is used to simulate the legal doctrine of avoidable consequences. These measures are then compared to substitute valuation measures that have been used by courts to determine welfare changes. For case 1, total revenue overestimated losses by 35.6%. For case 2, total revenue overestimates losses by 55.3%, tree replacement value underestimates losses by 93.6%, and changes in land value underestimates losses by 13.2%.citrus, perennial crops, catastrophic loss, damages, freeze, Crop Production/Industries,

Urban Sprawl and Farmland Prices

A theoretical model of farmland valuation is developed that allows urban sprawl to affect farmland values through the conversion of farmland to urban uses, shifts in production to higher-valued crops, and the speculative effect of urban pressure on farmland values. This model is estimated using county level data in the continental United States. Evidence is found for all three effects of urban sprawl on farmland values, with a significant contribution of urban pressure on net agricultural returns around major urban centers. Ancillary evidence supports that the latter effect is attributable to shifts to high-valued crops.hedonic determinants, land prices, spatial productivity, urban sprawl, Land Economics/Use, R14, Q15, D24, C33,

A Translog Cost Function Analysis of U.S. Agriculture: 1948-1999

This study examines the implications of the short-run specification of the standard, static translog cost function along with the possible implications of non-stationarity by estimating a dynamic translog cost specification complete with dynamic share equations for the U.S. using an empirical approach developed by Urga and Walters (2003). We compare the results of the static, long-run model with those of a dynamic, short-run error-correction model in terms of 1) significance of the parameter estimates, and 2) consistency with economic theory.Research Methods/ Statistical Methods,

Off-farm Income and Risky Investments: What Happens to Farm and Nonfarm Assets?

Off-farm work improves and reduces the riskiness of household income. Theoretical analyses reveal that the level and riskiness of off-farm income affect demand for farm/nonfarm investments. A two-limit Tobit model is estimated using ARMS data for 1996-2003. The impact on investment behaviour is evaluated.Farm Management,

Anisotropic perturbations due to dark energy

A variety of observational tests seem to suggest that the universe is anisotropic. This is incompatible with the standard dogma based on adiabatic, rotationally invariant perturbations. We point out that this is a consequence of the standard decomposition of the stress-energy tensor for the cosmological fluids, and that rotational invariance need not be assumed, if there is elastic rigidity in the dark energy. The dark energy required to achieve this might be provided by point symmetric domain wall network with $P/\rho=-2/3$, although the concept is more general. We illustrate this with reference to a model with cubic symmetry and discuss various aspects of the model.Comment: 4 pages, 3 figure