972 research outputs found
CHOICE SET CONSIDERATIONS IN MODELS OF RECREATION DEMAND: HISTORY AND CURRENT STATE OF THE ART
Demand and Price Analysis,
The Economic Value of Marine Recreational Fishing: Analysis of the MRFSS 1998 Pacific Add-on
Marine Recreational Fishing Statistics Survey (MRFSS) economic add-on data has been collected since 1994. The data are comprised of two geographically identical datasets for the Southeast region (1997, 2000), five identical datasets for the Northeast region (1994, 1996, 1997, 1999, 2000), and one dataset for the Pacific region (1998). Measures of the economic value of fishing sites and harvest have been derived from demand models estimated with data from the Northeast and the Southeast regions. In this paper we present a demand model estimated for the Pacific region (i.e., west coast). For consistency, the model is based on the 1994 and 1997 studies. Measures of the economic value of fishing sites and harvest are developed. We demonstrate how the model can be used for fisheries management decisions.
Explaining the Allocation of Bilateral and Multilateral Environmental Aid to Developing Countries
In this paper we examine how international development assistance for environmental purposes is allocated to developing countries. In particular, we investigate whether there are patterned differences between environmental aid for international public goods projects versus environmental projects having more localized impacts. We empirically investigate these questions using project project level development assistance data.International Development,
Angler Heterogeneity and the Species-Specific Demand for Marine Recreational Fishing
In this study we assess the viability of single-species recreation demand models given commonly available data sets. Using the 2000 MRFSS southeast intercept data combined with the economic add-on, we determine that the MRFSS data will support only a few species-specific recreation demand models. Considering species of management interest in the southeast, we focus on dolphin, king mackerel, red snapper and red drum. We examine single-species recreational fishing behavior using random utility models of demand. We explore mixed logit (i.e., random parameter) logit and finite mixture (i.e., latent class logit) models for dealing with angler heterogeneity. We compare these to the commonly used conditional and nested logit models in terms of the value of catching (and keeping) one additional fish. Mixed logit models illustrate that the value of catch can be highly heterogeneous and, in some cases, can include both positive and negative values. The finite mixture model generates value estimates that were some times strikingly different than conditional, nested and mixed logit models. Preference heterogeneity is significant within the MRFSS data. We find evidence that single-species models outperform multiple species models and recreational values differ. Key Words: marine recreational fishing, single-species demand, preference heterogeneity models
Optical Measurements in a Combustor Using a 9-Point Swirl-Venturi Fuel Injector
This paper highlights the use of two-dimensional data to characterize a multipoint swirl-venturi injector. The injector is based on a NASA-conceived lean direct injection concept. Using a variety of advanced optical diagnostic techniques, we examine the flows resultant from multipoint, lean-direct injectors that have nine injection sites arranged in a 3 x 3 grid. The measurements are made within an optically-accessible, jet-A-fueled, 76-mm by 76-mm flame tube combustor. Combustion species mapping and velocity measurements are obtained using planar laser-induced fluorescence of OH and fuel, planar laser scatter of liquid fuel, chemiluminescence from CH*, NO*, and OH*, and particle image velocimetry of seeded air (non-fueled). These measurements are used to study fuel injection, mixedness, and combustion processes and are part of a database of measurements that will be used for validating computational combustion models
Acute effects of single-bout exercise in adults with type 2 diabetes: a systematic review of randomised controlled trials and controlled crossover trials
Background: Exercise interventions improve type 2 diabetes (T2D). Published randomised control trials and crossover control trials were systematically examined to establish the differences in the effect of single-bout exercise on glucose control and insulin sensitivity in individuals with type 2 diabetes.Methods: Using PRISMA guidelines on three electronic databases, studies that tested the effects of a single bout of exercise on glucose control and insulin sensitivity in T2D were identified. To be included, studies had to meet the PRISMA criteria and contain data on the effects of a single bout of exercise on blood glucose and/or insulin resistance in individuals with T2D.Results: Three of the 205 articles met the inclusion criteria. All of the studies prescribed a single bout of continuous aerobic exercise at 40–60% heart rate reserve (HRR), 60% HRR, or 73% VO2 peak. Aerobic exercise was associated with improved glucose control when compared with resistance exercise. Continuous aerobic exercise significantly lowered average glucose during the first 24 hours post-exercise. Interval walking decreased mean and maximal blood glucose when compared with that in control.Conclusions: In conclusion, the findings of this review suggest high-intensity interval training to be the most effective form of exercise
Strategic Substitutes or Complements? The Game of Where to Fish
The ‘‘global game with strategic substitutes and complements’’ of Karp et al. (2007) is used to model the decision of where to fish. A complete information game is assumed, but the model is generalized to S \u3e 1 sites. In this game, a fisherman’s payoff depends on fish density in each site and the actions of other fishermen which can lead to congestion or agglomeration effects. Stable and unstable equilibria are characterized, as well as notions of equilibrium dominance. The model is applied to the Alaskan flatfish fishery by specifying a strategic interaction function (response to congestion) that is a non-linear function of the degree of congestion present in a given site. Results suggest that the interaction function may be non-monotonic in congestion
Flame Tube Testing of a GEA TAPS Injector: Effects of Fuel Staging on Combustor Fuel Spray Patterns, Flow Structure, and Speciation
This paper presents results in which we compare fuel staging and its effect on fuel spray pattern, velocity and speciation during combustion for several inlet conditions using a GE TAPS injector configuration. Planar laser-induced fluorescence (PLIF), particle image velocimetry (PIV) and phase Doppler interferometry (PDI) were used to investigate spray patterns and velocity. The 2D PIV provides slices in the flow of axial-vertical or axial horizontal velocity components. With 3D PDI, we obtained 3 components of velocity, and fuel drop sizes. Chemiluminescence imaging and spontaneous Raman scattering (SRS) were used to investigate flame structure, species location and relative species concentration. Phase Doppler and PIV data were acquired using scatter from fuel droplets; therefore, those data were obtained only at the pilot-only test points. Raman measurements were acquired only at 10/90 split points to avoid droplets
Excitation/Detection Strategies for OH Planar Laser-Induced Fluorescence Measurements in the Presence of Interfering Fuel Signal and Absorption Effects
Planar laser-induced fluorescence (PLIF) excitation/detection methods have been applied to obtain spatial distributions of the hydroxyl [OH] reacting intermediary and hydrocarbon [HC] primary species in laminar and turbulent combustion reactions. In this report, broadband and narrowband excitation/filtering techniques are explored to identify an optimal experimental configuration yielding significant fluorescent signal with low absorption losses. The combustion environments analyzed include 1) a laminar non-premixed methane/air flame and 2) a turbulent, non-premixed Jet-A/air fueled flame within a lean flame tube combustor. Hydrocarbon-based fuel and OH were excited via the R1 (1), R1(10) and R2(7) transitions of the A(sup 2)Epsilon(+) X(sup 2)pi(1,0) band using a broadband Nd:YAG pumped optical parametric oscillator (OPO) and narrowband Nd:YAG/dye laser with ultraviolet frequency extension (UVX) package. Variables tested for influence on fluorescent signal and absorption characteristics were excitation line, laser energy, exciting linewidth, combustion reactants, and test flow conditions. Results are intended to guide the transition from a dye/UVX laser to an OPO system for performing advanced diagnostics of low-emission combustion concepts
Optical Characterization of Fuel Injection in a Flame Tube Combustor Using a GE TAPS Injector Configuration
This paper presents results in which we compare fuel staging and its effect on fuel spray pattern, velocity and speciation during combustion for several inlet conditions using a GE TAPS injector configuration. Planar laser-induced fluorescence (PLIF), particle image velocimetry (PIV) and phase Doppler interferometry (PDI) were used to investigate spray patterns and velocity. The 2D PIV provides slices in the flow of axial-vertical or axial horizontal velocity components. With 3D PDI, we obtained 3 components of velocity, and fuel drop sizes. Chemiluminescence imaging and spontaneous Raman scattering (SRS) were used to investigate flame structure, species location and relative species concentration. Phase Doppler and PIV data were acquired using scatter from fuel droplets; therefore, those data were obtained only at the pilot-only test points. Raman measurements were acquired only at 10/90 split points to avoid droplets
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