Allocating Yellowfin Tuna Between the Multispecies Purse Seine and Longline Fleets

Yellowfin tuna in the western Pacific are harvested as juveniles by purse seiners and as adults by longliners. The study presents estimates of the multi-species harvest technology of these two types of vessel operating in Papua New Guinea's Exclusive Economic Zone. The results, together with price and cost information and estimates of the impact of the purse seine catch on the catch rates of longline vessels are used to perform a benefit/cost analysis of a reallocation of juvenile yellowfin through a one percent decline in purse seine harvest in PNG's EEZ. The marginal benefit of investment in the yellowfin stock is found to exceed that of marginal cost, suggesting that there may be an economic case for a reallocation.resource sharing, multispecies fisheries, yellowfin tuna, Environmental Economics and Policy, International Development, International Relations/Trade, Resource /Energy Economics and Policy,

Soft gluons in Higgs plus two jet production

We investigate the effects of an all order QCD resummation of soft gluon emissions for Higgs boson production in association with two hard jets. We consider both the gluon-gluon fusion and weak boson fusion processes and show how to resum a large part of the leading logarithms in the jet veto scale. Our resummation improves on previous analyses which also aim to include the effects of multiple soft gluon radiation. In addition we calculate the interference between weak boson fusion and gluon-gluon fusion and find that it is small.Comment: 15 pages and 5 figure

Soil profile modification and cotton production

Hardpan soils of the southeastern Coastal Plains were mixed to depths up to 0.61 m in an attempt to alleviate strength problems associated with a subsurface pan. It was hypothesized that mixing the dense, coarse-textured E Horizon with the less dense Ap and the relatively clayey B horizon would increase the water-holding capacity of the E and decrease its strength. Mixed soil did have a higher amount of water held than the unmixed E, increasing it from 5 to 7% at -200 kPa matric potential. This would reduce its strength by approximately 0.1 MPa allowing easier root penetration whether the increased water is available for uptake or not. Although seed cotton in the deeply-mixed treatments outyielded the moldboard-plowed treatments by 233 kg/ha in one year, they were outyielded by 132 kg/ha in another year. The decrease in strength and the increases of retention as a result of the mixing were small and infiltration was unchanged. Furthermore, mixing of field samples was less homogenous than lab samples. It is doubtful that the level of improvement of cotton would warrant the effort involved in the mixing operation. Treatments at two sites were split into fertility subplots. The only significant fertility difference was between rates of N sidedressed when plants were about 0.40 m tall. The 20 kg/ha rate outyielded the 67 kg/ha rate by up to 300 kg/ha presumably because the higher rate encouraged vegetative growth and retarded boll formation which in turn limited lint and seed production. Interactions between tillage or mixing and fertility were non-significant. Plants grew better in the deeper disturbed soils in dryer years. Other crops may respond more favorably to the mixing

A new model for predicting adsorption of polar molecules in MOFs with unsaturated metal sites

Large-scale computational screening has the potential to translate the tailorability of metal-organic frameworks (MOFs) into actual applications, but requires the availability of accurate forcefields. Unfortunately, conventional molecular models fail to correctly describe interactions of adsorbates with coordinatively unsaturated sites (CUS) present in a large number of MOFs. Here, we confirm the failure of these models for a prototypical polar adsorbate, carbon monoxide, and show that simply adjusting their parameters leads to poor agreement with experiment isotherms when outside the fitting conditions. Building upon our previous work on non-polar hydrocarbons, we propose a new approach that combines quantum mechanical Density Functional Theory (DFT) with Monte Carlo simulations to rigorously account for specific interactions at the CUS. By explicitly including electrostatic interactions and employing accurate DFT functionals that describe dispersion interactions, our modeling approach becomes generally applicable to both polar and non-polar molecules. We demonstrate that this CUS model leads to substantial improvement in carbon monoxide adsorption isotherm predictions, and correctly captures the coordination binding mechanism. Furthermore, the model retains the transferability demonstrated in our previous work. This paper represents a major stepping stone in the development of a robust, transferable and generally applicable approach to describe the complex interactions between gas molecules and CUS, with great potential for use in large scale screening studies

Organic film thickness influence on the bias stress instability in Sexithiophene Field Effect Transistors

In this paper, the dynamics of bias stress phenomenon in Sexithiophene (T6) Field Effect Transistors (FETs) has been investigated. T6 FETs have been fabricated by vacuum depositing films with thickness from 10 nm to 130 nm on Si/SiO2 substrates. After the T6 film structural analysis by X-Ray diffraction and the FET electrical investigation focused on carrier mobility evaluation, bias stress instability parameters have been estimated and discussed in the context of existing models. By increasing the film thickness, a clear correlation between the stress parameters and the structural properties of the organic layer has been highlighted. Conversely, the mobility values result almost thickness independent

An explicit formula for the coefficients in Laplace's method

Laplace's method is one of the fundamental techniques in the asymptotic approximation of integrals. The coefficients appearing in the resulting asymptotic expansion, arise as the coefficients of a convergent or asymptotic series of a function defined in an implicit form. Due to the tedious computation of these coefficients, most standard textbooks on asymptotic approximations of integrals do not give explicit formulas for them. Nevertheless, we can find some more or less explicit representations for the coefficients in the literature: Perron's formula gives them in terms of derivatives of an explicit function; Campbell, Fr\"oman and Walles simplified Perron's method by computing these derivatives using an explicit recurrence relation. The most recent contribution is due to Wojdylo, who rediscovered the Campbell, Fr\"oman and Walles formula and rewrote it in terms of partial ordinary Bell polynomials. In this paper, we provide an alternative representation for the coefficients, which contains ordinary potential polynomials. The proof is based on Perron's formula and a theorem of Comtet. The asymptotic expansions of the gamma function and the incomplete gamma function are given as illustrations.Comment: 14 pages, to appear in Constructive Approximatio