Random Utility Models of Recreational Fishing: Catching Fish Using a Poisson Process

This paper presents a Poisson model of expected angler catch during a sportfishing trip and employs the expected catch in a random utility model of site choice. The approach permits greater heterogeneity in expected catch and in individual welfare estimates from policies such as creel limits.sportfishing, creel limits, expected catch, Environmental Economics and Policy, Resource /Energy Economics and Policy,

A Random Utility Model for Sportfishing: Some Preliminary Results for Florida

The gray literature in the field of nonmarket benefit measurement has made extensive use of the random utility (or discrete choice) model in recent years, but few applications appear in the literature. This article provides such an application, illustrating the technique with preliminary results from a regional study modeling east cost sportfishing behavior. The article discusses some of the strengths and weaknesses of the random utility model. It also illustrates how data regularly collected by the National Marine Fisheries Service can be supplemented with economic survey data to estimate these discrete choice behavioral models.Random utility, discrete choice, sportfishing, nonmarket benefits, environmental quality, Environmental Economics and Policy, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,

Development of the NASA VALT digital navigation system

The research to develop and fabricate a terminal area navigation system for use in the NASA VTOL Approach and Landing Technology (VALT) program. The results of that effort are reported. The navigation system developed and fabricated was based on a general purpose airborne digital computer. A set of flight hardware units was fabricated to create the necessary analog, digital and human interface with the computer. A comprehensive package of software was created to implement the control and guidance laws required for automatic and flight director approaches that are curved in two planes. A technique was developed that enables the generation of randomly shaped lateral paths from simple input data. The lateral path concept combines straight line and elliptical-curved segments to fit a continuous curved path to the data points. A simple, fixed base simulation was put together to assist in developing and evaluating the system. The simulation was used to obtain system performance data during simulated curved-path approaches

Measuring the Benefits of Improvements in Water Quality: The Chesapeake Bay

Federal, state, and local government agencies have joined forces in the ambitious and expensive task of improving the water quality of the Chesapeake Bay. Clean-up efforts will be devoted to three major problems: nutrient over enrichment, toxic substances, and the decline of submerged aquatic vegetation. Although the beneficiaries are ultimately human, criteria for judging the Bay's water quality have been primarily biological and physical. This paper addresses the question of the human values from the Bay. How do people use the Bay and how much are they willing to pay for the changes in water quality that improve their use? With a variety of methods and data sources, we estimate the annual aggregate willingness to pay for a moderate improvement in the Chesapeake Bay's water quality to be in the range of $10 to$100 million in 1984 dollars.Community/Rural/Urban Development, Environmental Economics and Policy, Resource /Energy Economics and Policy,

A technique for generating arbitrarily shaped curved approach paths

A technique for creating and using arbitrarily curved flight paths is described, in conjunction with either automatic or manual guidance. Operating techniques for VTOL aircraft in the terminal area environment are investigated. Straight lines and elliptical segments to connect a series of data points into a continous approach path were developed. Software was created to allow the generation of arbitrarily shaped altitude and speed profiles in conjunction with the lateral curved paths

Study for incorporating time-synchronized approach control into the CH-47/VALT digital navigation system

Techniques for obtaining time synchronized (4D) approach control in the VALT research helicopter is described. Various 4D concepts and their compatibility with the existing VALT digital computer navigation and guidance system hardware and software are examined. Modifications to various techniques were investigated in order to take advantage of the unique operating characteristics of the helicopter in the terminal area. A 4D system is proposed, combining the direct to maneuver with the existing VALT curved path generation capability

The Law of Interspersion and the Principle of Edge: Old Arguments and a New Synthesis

Leopold’s interspersion hypothesis has experienced fluctuating acceptance, opposition and neglect due to its unintentional ambiguous description and seemingly simplistically universal application. Originally developed to describe the positive association between animal density and habitat heterogeneity in the landscape, the hypothesis has been mischaracterized as the principle of edge resulting from Guthery and Bingham’s (1992) assertion that the interspersion hypothesis could be modeled by the amount of ‘high contrast’ edge and that edge density and interspersion were synonymous. We contend that Leopold’s original intention was not to promote more edge density is always better but rather to promote interspersion of habitat types within landscapes suitable for bobwhite. We argue that edge density and interspersion are different metrics to describe landscape configuration but are incorrectly used interchangeably. These metrics reflect two unique hypotheses regarding bobwhite relationships with landscape structure. We used a northern bobwhite (Colinus virginianus) monitoring dataset to demonstrate the importance of the proper use of edge density and interspersion metrics. We modeled bobwhite abundance at 160 sites across 6 years using an open N-mixture model. We used Fragstats to calculate edge density and interspersion at the landscape scale. These metrics were not correlated (r \u3c .10) indicating they describe unique aspects of configurational heterogeneity. Both metrics had positive but varying effects on bobwhite abundance. We recommend scientists have explicit a priori hypothesis regarding the differential effects of edge density and interspersion

DRC-1339 AND DRC-2698 RESIDUES IN STARLINGS: PRELIMINARY EVALUATION OF THEIR EFFECTS ON SECONDARY HAZARD POTENTIAL

DRC-1339 (3-chloro-4-methylbenzenamine HCI) is the active ingredient in Starlicide Complete, a commercial bait used to control starlings (Sturnus vulgaris) at animal feedlots throughout the U.S. Because of the recent widespread use of this product, par- ticularly within the wintering range of many raptors, they and other avian or mammalian scavenger or predator species may be exposed to large numbers of dead or dying star- lings and blackbirds (Icteridae) throughout the winter roosting season (November-March). Acute toxicity data are available for five species of raptors and a number of mammals indicating that DRC-1339 or its primary toxic metabolite DRC-2698 (N-(3-chloro-4-methylphenyl) acetamide, CAT), a potential roost toxicant, are only moderately toxic (100-300 mg/kg) to these animals. However, there are some avian and mammalian scavengers or predators to which these compounds are considerably more toxic (i.e., cats, owls, magpies). Secondary hazards have not been observed when DRC-1339 killed starlings were fed to three raptor species for as long as 141 days and to domestic cats for seven days (DeCino, Cunningham and Schafer 1966; Holler et al. 1979, unpubl, manuscript); however, the direct long-term effects of both chemicals have not been determined on raptors or other predatory or scavenger species. In order to decide if long-term studies are needed on predator or scavenger species, it is necessary to estimate accurately the degree of expected exposure to DRC-1339 and DRC-2698under actual use conditions. Since exposure will depend primarily upon the amount of these chemicals that remains in bird carcasses from bait ingestion until death, the metabolic or excretion rate of DRC-1339 and DRC-2698 must be known in target and at-risk, nontarget bird species. Although considerable data are available to determine the metabolic or excretion rate of DRC-1339 in target birds, some of these data are conflicting. We are therefore presenting the preliminary results of some of our current research with DRC-1339 and DRC-2698

An Empirical Examination of Certain Aspects of Auditor Changes in NYSE, AMEX, and Selected OTC Companies

The purpose of this thesis was to analyze a number of auditor change and other peripheral issues from two related perspectives. Empirical data were gathered from publicly available Forms 8-K and 10-K to first assess whether meaningful differences existed between NYSE, AMEX, and OTC registrants regarding disclosures required in those documents. Secondly, the data were analyzed to determine whether differences existed with respect to the accounting firms (Big Eight or non-Big Eight) involved in the auditor changes. In most of the tests designed to achieve these purposes, statistically defensible results were obtained using the nonparametric chi-square test for significance of observed differences and the McNemar test for significance of changes, at the .05 level

Comment on "low time resolution analysis of polar ice cores cannot detect impulsive nitrate events" by D.F. Smart et al.

Smart et al. (2014) suggested that the detection of nitrate spikes in polar ice cores from solar energetic particle (SEP) events could be achieved if an analytical system with sufficiently high resolution was used. Here we show that the spikes they associate with SEP events are not reliably recorded in cores from the same location, even when the resolution is clearly adequate. We explain the processes that limit the effective resolution of ice cores. Liquid conductivity data suggests that the observed spikes are associated with sodium or another non-acidic cation, making it likely that they result from deposition of sea salt or similar aerosol that has scavenged nitrate, rather than from a primary input of nitrate in the troposphere. We consider that there is no evidence at present to support the identification of any spikes in nitrate as representing SEP events. Although such events undoubtedly create nitrate in the atmosphere, we see no plausible route to using nitrate spikes to document the statistics of such events.EW is supported by a Royal Society Professorship.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/2015JA02157