MODELING NONNEGATIVITY VIA TRUNCATED LOGISTIC AND NORMAL DISTRIBUTIONS: AN APPLICATION TO RANCH LAND PRICE ANALYSIS

This study presents an empirical method of modeling the nonnegativity of dependent variables using truncated logistic and normal disturbance distributions. The method is applied in estimating a ranch land hedonic price function. Results show that the degree of truncation is significant.Land Economics/Use,

Temporal Changes of Largemouth Bass Alleles in a Northern Arkansas Reservoir Stocked with Florida Bass

Southwest Electric Power Company (SWEPCO) Lake in northwest Arkansas is a thermal cooling pond for the Flint Creek Power Station. This reservoir has been regularly stocked with Florida bass (Micropterus floridanus) on top of a pre-existent largemouth bass (M. salmoides) population since its creation in 1976. Allozyme analysis of diagnostic loci in 1995-1996 revealed that 62% of the alleles were Florida bass alleles and that most fish were FX hybrids (77%). Microsatellite analysis of diagnostic loci in 2006 revealed that 78% of the alleles were Florida bass alleles and that most fish were FX-Florida hybrid bass (59%), with the remainder designated as Florida bass. The ongoing stocking of Florida bass and the possibility of a selective advantage for Florida bass alleles in a thermal pond may account for these temporal reductions in largemouth bass allele frequencies

Control and coherence of the optical transition of single defect centers in diamond

We demonstrate coherent control of the optical transition of single Nitrogen-Vacancy defect centers in diamond. On applying short resonant laser pulses, we observe optical Rabi oscillations with a half-period as short as 1 nanosecond, an order of magnitude shorter than the spontaneous emission time. By studying the decay of Rabi oscillations, we find that the decoherence is dominated by laser-induced spectral jumps. By using a low-power probe pulse as a detuning sensor and applying post-selection, we demonstrate that spectral diffusion can be overcome in this system to generate coherent photons.Comment: 5 pages,4 figure

Economic and psychological approaches to risk-bearing : theory and experimental evidence / BEBR No. 603

Title page includes summary.Includes bibliographical references (p. 44-45)

Condition Relative to Phenotype for Bass Populations in Southern Arkansas Lakes

Southern Arkansas reservoir largemouth bass populations (Micropterus salmoides) are often supplemented with stocks of Florida bass (M. floridanus) in an attempt to boost the frequency of hybrid and trophy bass. Stocking rates of Florida bass among these lakes are highly variable. We determined bass phenotype composition among 12 lake populations based upon stocking protocols: exclusively Florida bass, primarily Florida bass, mixed stocking protocol and primarily largemouth bass. We also compared condition among phenotypes (n =2,100) to test for hybrid or phenotype vigor. Mean relative weight of bass for most lakes but SWEPCO Lake (mean Wr = 72) were ≥ 90. Phenotype frequencies were inconsistent with FB stocking histories. No lake population was comprised only with pure Florida bass despite four of the lakes being stocked solely with this bass species. Numbers of F1 hybrid bass were low for all lake samples. Relative weight among phenotypes was also inconsistent among lake samples, allowing no conclusions to be made regarding relative weight and hybrid vigor or phenotype. Further testing increasing both the number of lake samples and sample size within lakes may provide insight into these questions of stocking effectiveness of Florida bass and hybrid or phenotype vigor

Interim Guidelines for Design of Highway Pavements

The adequacy of a pavement design is directly related to the accuracy of traffic data, axle load information and materials data. It is assumed that appropriate construction procedures will be employed and that the pavements will be maintained periodically during the course of their service lives. It is assumed that the subgrade will be constructed at or near the optimum moisture content and to the maximum dry density as specified in appropriate standard specifications. It is also assumed that the base course materials meet design requirements, that the aggregates will meet soundness and durability requirements and that the aggregate base will be compacted to specified densities. Pavement layers should meet mixture design requirements and be compacted to specified densities. The construction process should be structured to provide as homogenous a pavement layer as practical within the limits of existing construction practices. In the event it is not possible to construct pavements to meet design assumptions, pavement designs should be modified to reflect actual construction conditions. Most pavement thickness design procedures (including. the Kentucky procedures) are founded on the assumptions that quality materials will be used to construct the pavement, that appropriate construction conditions exist, and that appropriate construction procedures will be used. It is possible to develop pavement thickness designs for less than ideal conditions or for marginal materials. Examples of pavement designs involving marginal materials include those pavement designs wherein by-product (waste) materials have been used in one or more layers of the pavement structure. The level of pavement performance associated with a given thickness design also presumes some level of routine pavement maintenance. Designs may be modified to reflect other levels of maintenance such as the zero maintenance concept. This interim design guide addresses only pavement designs presuming adequate subgrade construction conditions, appropriate construction techniques for aggregate and pavement layers, accurate information concerning the strengths and quality of materials used in the pavement, and accurate information concerning the magnitude and quantity of loads for which the pavement is designed to accommodate. Alternate design strategies should be used in the event these assumptions are violated

Geotechnical, Hydrologic, and Hydraulic Investigation of Mill Creek Dam-Phase II

The general scope of this study, Phase II, was to assess the safety of Mill Creek Dam. Findings obtained from detailed geotechnical, hydraulic, and hydrological investigations are presented. The structural stability, as well as the hydrological and hydraulic stability, were investigated. Specifically, objectives of the study were as follows: 1. To determine the engineering characteristics of the clay core, shells, and random fill. 2. To evaluate the potential for piping. 3. To evaluate seepage conditions at the site. 4. To evaluate the structural stability of the earth and rockfill dam. 5. To evaluate erodability. 6. To assess geologic conditions at the site. 7. To evaluate existing and required spillway hydraulics and hydrology of the site. 8. To analyze requirements for a drawdown facility. 9. To evaluate alternative remedial measures that could be used to correct deficiencies in the dam. This study presents data relating to the degree of safety and alternative remedial schemes. Information presented herein will aid in the final selection of the remedial method and in implementing remedial construction. Development of detailed remedial plans, however, was not within the scope of this study