Transonic Elastic Model for Wiggly Goto-Nambu String

The hitherto controversial proposition that a ``wiggly" Goto-Nambu cosmic string can be effectively represented by an elastic string model of exactly transonic type (with energy density $U$ inversely proportional to its tension $T$) is shown to have a firm mathematical basis.Comment: 8 pages, plain TeX, no figure

Men Are More Likely than Women to Slow in the Marathon

Studies on nonelite distance runners suggest that men are more likely than women to slow their pace in a marathon. Purpose: This study determined the reliability of the sex difference in pacing across many marathons and after adjusting women\u27s performances by 12% to address men\u27s greater maximal oxygen uptake and also incorporating information on racing experience. Methods: Data were acquired from 14 US marathons in 2011 and encompassed 91,929 performances. For 2929 runners, we obtained experience data from a race-aggregating Web site. We operationalized pace maintenance as the percentage change in pace observed in the second half of the marathon relative to the first half. Pace maintenance was analyzed as a continuous variable and as two categorical variables, as follows: maintain the pace, defined as slowing=30%. Results: The mean change in pace was 15.6% and 11.7% for men and women, respectively (P \u3c 0.0001). This sex difference was significant for all 14 marathons. The odds for women were 1.46 (95% confidence interval, 1.41–1.50; P \u3c 0.0001) times higher than men to maintain the pace and 0.36 (95% confidence interval, 0.34–0.38; P \u3c 0.0001) times that of men to exhibit marked slowing. Slower finishing times were associated with greater slowing, especially in men (interaction, P \u3c 0.0001). However, the sex difference in pacing occurred across age and finishing time groups. Making the 12% adjustment to women’s performances lessened the magnitude of the sex difference in pacing but not its occurrence. Although greater experience was associated with less slowing, controlling for the experience variables did not eliminate the sex difference in pacing. Conclusions: The sex difference in pacing is robust. It may reflect sex differences in physiology, decision making, or both

Symplectic structure for elastic and chiral conducting cosmic string models

This article is based on the covariant canonical formalism and corresponding symplectic structure on phase space developed by Witten, Zuckerman and others in the context of field theory. After recalling the basic principles of this procedure, we construct the conserved bilinear symplectic current for generic elastic string models. These models describe current carrying cosmic strings evolving in an arbitrary curved background spacetime. Particular attention is paid to the special case of the chiral string for which the worldsheet current is null. Different formulations of the chiral string action are discussed in detail, and as a result the integrability property of the chiral string is clarified.Comment: 18 page

Reusable Agena study. Volume 2: Technical

The application of the existing Agena vehicle as a reusable upper stage for the space shuttle is discussed. The primary objective of the study is to define those changes to the Agena required for it to function in the reusable mode in the 100 percent capture of the NASA-DOD mission model. This 100 percent capture is achieved without use of kick motors or stages by simply increasing the Agena propellant load by using optional strap-on-tanks. The required shuttle support equipment, launch and flight operations techniques, development program, and cost package are also defined

Charged particle radiation damage in semiconductors, 15 - Study and determination of an optimum design for space utilized lithium doped solar cells, part 1 Interim final report

Hall coefficient measurements of irradiated lithium doped solar cell

Charged particle radiation damage in semiconductors. Part 14 - Study of radiation effects in lithium doped silicon solar cells

Lithium doped silicon solar cells under electron irradiation and determination of semiconductor parameter

IMPACTS OF PESTICIDE REGULATION ON THE CALIFORNIA STRAWBERRY INDUSTRY

Environmental regulation of agriculture is becoming increasingly important, and growers are increasingly concerned about the effects of regulations on their profitability. Regulations governing the use of a pesticide affect its economic value. Further, growers often face a choice among pesticide alternatives, each with its own set of regulatory restrictions. In this environment, the introduction of a new regulation can have complex effects on growers' profit-maximizing pesticide choices. Buffer zones and regional emissions caps mean that pesticide choices can have important spatial components. Our paper presents an optimization model that incorporates spatial considerations at the field and regional level. We apply our model to fumigant choice by California strawberry growers. The industry is facing an impending ban on the use of methyl bromide, which in conjunction with chloropicrin was the standard fumigant for over forty years. In addition to the forthcoming ban, the state government has imposed regulations governing methyl bromide application, including buffer zones, etc. These extreme use restrictions provide us with an interesting environment for modeling the effects of pesticide regulations. There are currently two legally available fumigants that may substitute for methyl bromide in strawberries: 1,3-D and chloropicrin. 1, 3-D is subject to township caps and other restrictions. Township caps limit total application in an area. The California Department of Pesticide Regulation is currently undertaking air monitoring and other activities to determine whether or not buffer zones and other restrictions should be applied to chloropicrin. We evaluate the effects of current and proposed regulations on field-level decisions and industry costs and returns. Methodology To the best of our knowledge, no study has examined the role of pesticide use regulations in determining growers' profit-maximizing pesticide choices at the field level. We do so by combining three datasets with a field-level spatial model of the profit-maximizing fumigation decision. The first dataset includes detailed field-level information regarding the costs and yields associated with alternative fumigants obtained from a multi-disciplinary research project. The second includes chemical-specific California use regulations regarding treatment rates, buffer zones, and other restrictions. The third includes information on the shapes and sizes of strawberry fields in California. Using these data, the optimization model computes the profit-maximizing treatment for each field including pattern of treatment and number of acres treated per day, etc. Field-level results are aggregated to evaluate the impact of regional pesticide regulations, and then to estimate the industry-level effects of current and proposed pesticide use regulations. We model the effects of the entire regulatory system on the fumigation decisions made by farmers. The restrictions on fumigants are integrated into a field-level programming model of a grower's fumigant decision choice. The program calculates the optimal fumigation plan for a field, given the field's size and shape, and use regulations, and per-acre costs and returns associated with each fumigant. The resulting field-level choices are aggregated in order to check for consistency with township caps. If caps are exceeded, the model is rerun using a number of allocation rules. All choices for all fields are aggregated in order to obtain industry-level results. We perform this procedure for the current set of restrictions and for several alternative sets, assessing the profitability of each alternative. For example, we remove the existing township caps on 1,3-D and evaluate how much the results change. We include varying buffer zone restrictions on chloropicrin, and evaluate whether growers' fumigant choices are sensitive to the size of the buffer zone. Relevance Environmental regulation of agriculture is becoming increasingly important. By explicitly analyzing the effect of regulations affecting methyl bromide alternatives in a model that includes both the spatial dimensions of some regulations and the costs and yields associated with each alternative, we will obtain a more detailed and accurate assessment of the costs of these regulations than is currently available. Our results will provide a greater understanding of the effects of these regulations on industry profitability, and how these regulations interact. Our model can be applied to other cases of pesticide regulations. Given the increasing importance of environmental regulation in agriculture, it is important to aid policymakers in understanding how regulations interact with each other, possibly in unexpected ways.Environmental Economics and Policy,

Physics at the B Factories

We review recent progress at the two $e^+ e^-$ B factories. The first measurement of CP violation and the prospects for measuring all the angles of the unitarity triangle are discussed.Comment: To appear in the Proceedings of From the Smallest to the Largest Distances, a conference in honor of Tranh Thanh Van in Moscow, Russi

Hanging drop crystal growth apparatus

This invention relates generally to control systems for controlling crystal growth, and more particularly to such a system which uses a beam of light refracted by the fluid in which crystals are growing to detect concentration of solutes in the liquid. In a hanging drop apparatus, a laser beam is directed onto drop which refracts the laser light into primary and secondary bows, respectively, which in turn fall upon linear diode detector arrays. As concentration of solutes in drop increases due to solvent removal, these bows move farther apart on the arrays, with the relative separation being detected by arrays and used by a computer to adjust solvent vapor transport from the drop. A forward scattering detector is used to detect crystal nucleation in drop, and a humidity detector is used, in one embodiment, to detect relative humidity in the enclosure wherein drop is suspended. The novelty of this invention lies in utilizing angular variance of light refracted from drop to infer, by a computer algorithm, concentration of solutes therein. Additional novelty is believed to lie in using a forward scattering detector to detect nucleating crystallites in drop

Collapsing Layers on Schwarzschild-Lemaitre Geodesics

We discuss Israel layers collapsing inward from rest at infinity along Schwarzschild-Lemaitre geodesics. The dynamics of the collapsing layer and its equation of state are developed. There is a general equation of state which is approximately polytropic in the limit of very low pressure. The equation of state establishes a new limit on the stress-density ratio.Comment: To appear in Phys. Rev. D 1