SIZE AND BAG LIMITS IN RECREATIONAL FISHERIES: THEORETICAL AND EMPIRICAL ANALYSIS

Size and bag limits are among the most common forms of regulations for recreational fisheries. In this paper, we theoretically study and compare the short- and long-term impacts of these policies on individual anglers and fish stocks. Particular attention is paid to the issue of release mortality, which can have important consequences for policy effectiveness. Theoretically, we show the conditions under which these policies will be successful in achieving biological objectives. Implications for recreation demand analysis are discussed. We also study these policies using a simulation model of various policy combinations for the Gulf of Mexico red snapper fishery.Resource /Energy Economics and Policy,

ECONOMIC EFFICIENCY OF ALTERNATIVE BYCATCH-REDUCTION POLICIES AND BYCATCH REDUCTION DEVICES

This paper examines the ability of two new policies to reduce bycatch of red snapper by the shrimp fishery in the Gulf of Mexico: Fractional License and Fractional Gear Programs, as proposed by Townsend, reduce bycatch by reducing the effort levels of shrimp vessels. The policies are evaluated both theoretically and using a simulation model, and they are compared with the current regulatory policy requiring shrimp vessels to use bycatch reduction devices to rebuild red snapper stocks. We find that either a FL program or a FG program could reduce effort and the related problem of bycatch resulting in improving red snapper stocks, while at the same time increasing economic welfare in the fishery.Resource /Energy Economics and Policy,

Transferable Rights of Recreational Fishery: An Application to Red Snapper Fishery in the Gulf of Mexico

Transferable rights (TRs) programs are being increasingly considered in fisheries to overcome current overfishing situation. This paper will focus on developing a conceptual foundation, investigating advantages of the TRs program in fishery management, and answering critical issues to implement recreational TRs programs. Implication is to the Gulf of Mexico red snapper fishery.Transferable Rights, Individual Transferable Quota, Recreational Fishery, Resource /Energy Economics and Policy, Q22,

Joint Estimation of Revealed and Stated Preference Data: An Application to Recreational Red Snapper Valuation

This study extends the joint estimation of revealed and stated preference data literature by accounting for truncation in the revealed preference data. The analytical model and estimation procedure are used to estimate the value of recreational red snapper fishing in the Gulf of Mexico. This recreational red snapper valuation is decomposed into its direct and indirect components. As expected, the value of recreational red snapper fishing using the joint revealed-stated preference model proposed in this analysis is bracketed on the upper limit by the value obtained using the contingent valuation method and on the lower limit by the travel cost method. The results also indicate that the joint model improves the precision of estimated recreational red snapper valuation.Resource /Energy Economics and Policy,

Optimal Nitrogen Applications: A Stochastic Dynamic Model of Irrigated Corn in the Southern High Plains

Crop Production/Industries,

On the density-potential mapping in time-dependent density functional theory

The key questions of uniqueness and existence in time-dependent density functional theory are usually formulated only for potentials and densities that are analytic in time. Simple examples, standard in quantum mechanics, lead however to non-analyticities. We reformulate these questions in terms of a non-linear Schr\"odinger equation with a potential that depends non-locally on the wavefunction.Comment: 8 pages, 2 figure

The NASA Ames Research Center one- and two-dimensional stratospheric models. Part 2: The two-dimensional model

The two-dimensional model of stratospheric constituents is presented in detail. The derivation of pertinent transport parameters and the numerical solution of the species continuity equations, including a technique for treating the stiff differential equations that represent the chemical kinetic terms, and appropriate methods for simulating the diurnal variations of the solar zenith angle and species concentrations are discussed. Predicted distributions of tracer constituents (ozone, carbon 14, nitric acid) are compared with observed distributions

Effects of Training Intensity on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

Background. Many physical interventions can improve locomotor function in individuals with motor incomplete spinal cord injury (iSCI), although the training parameters that maximize recovery are not clear. Previous studies in individuals with other neurologic injuries suggest the intensity of locomotor training (LT) may positively influence walking outcomes. However, the effects of intensity during training of individuals with iSCI have not been tested. Objective. The purpose of this pilot, blinded-assessor randomized trial was to evaluate the effects of LT intensity on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI \u3e1 year duration performed either high- or low-intensity LT for ≤20 sessions over 4 to 6 weeks. Four weeks following completion, the training interventions were alternated. Targeted intensities focused on achieving specific ranges of heart rate (HR) or ratings of perceived exertion (RPE), with intensity manipulated by increasing speeds or applying loads. Results. Significantly greater increases in peak treadmill speeds (0.18 vs 0.02 m/s) and secondary measures of metabolic function and overground speed were observed following high- versus low-intensity training, with no effects of intervention order. Moderate to high correlations were observed between differences in walking speed or distances and differences in HRs or RPEs during high- versus low-intensity training. Conclusion. This pilot study provides the first evidence that the intensity of stepping practice may be an important determinant of LT outcomes in individuals with iSCI. Whether such training is feasible in larger patient populations and contributes to improved locomotor outcomes deserves further consideration

Environmental effects of SPS: The middle atmosphere

The heavy lift launch vehicle associated with the solar power satellite (SPS) would deposit in the upper atmosphere exhaust and reentry products which could modify the composition of the stratosphere, mesosphere, and lower ionosphere. In order to assess such effects, atmospheric model simulations were performed, especially considering a geographic zone centered at the launch and reentry latitudes