MODELING A RIGHTS‐BASED APPROACH FOR MANAGING HABITAT IMPACTS OF FISHERIES

ABSTRACT. Limiting adverse consequences of fishing on essential fish habitat has emerged as a key fishery management objective. The conventional approach to providing habitat protection is to create MPAs or marine reserves that prohibit all or certain types of fishing in specific areas. However, there may be more cost‐effective and flexible ways to provide habitat protection. We propose an individual habitat quota (IHQ) system for habitat conservation that would utilize economic incentives to achieve habitat conservation goals cost‐effectively. Individual quotas of habitat impact units (HIU) would be distributed to fishers with an aggregate quota set to maintain a target habitat “stock.” HIU use would be based on a proxy for marginal habitat damage. We use a dynamic, explicitly spatial fishery and habitat simulation model to explore how such a system might work. We examine how outcomes are affected by spatial heterogeneity in the fishery and the scale of habitat regulation. We find that the IHQ system is a highly cost‐effective means of ensuring a given level of habitat protection, but that spatial heterogeneity and the scale of regulation can have significant effects on the distribution of habitat protection.     

AN INDIVIDUAL‐BASED MODEL FOR FERAL HOGS IN GREAT SMOKY MOUNTAINS NATIONAL PARK

The expansion of feral hog (Sus scrofa) populations in the United States has resulted in increased efforts to develop and implement control strategies designed to minimize the impacts done by this invasive species. We describe an individual‐based model for feral hogs in Great Smoky Mountains National Park (GSMNP). The objectives of the model are to provide an understanding of the population dynamics of this feral hog population and to determine the efficacy of the annual harvest as a population control method. Results suggest that the dynamics of the population are driven by fall hard mast production and the GSMNP harvests currently limit growth of the population, but these control efforts have not reduced the population.     

Harmonics in the stress response of a WCA-Lennard-Jones liquid under oscillatory elongational flow

The WCA fluid shows a nonlinear behaviour toward a periodic elongational flow through the presence of higher harmonics in stress responses. At the same time the liquid remains purely viscous and isotropic. The absence of numerical artefacts is checked and the physical origin of the harmonics is discussed.     

MODELING THE DYNAMICS OF FISHERY STOCK RECOVERY: IMPLICATIONS FOR THE ASSESSMENT OF NATURAL RESOURCE DAMAGES

ABSTRACT. During the restoration planning phase of the natural resource damage assessment (NRDA) process, potential injuries to natural resources and services are evaluated in terms of the nature, degree and extent of injury so that the need for and scale of restoration actions can be ascertained. Injuries are quantified by comparing the condition of the injured natural resource relative to baseline (pre‐injury) conditions. The “Type A” procedures are used to quantify damages from smaller spills and rely on a standardized methodology and computer model to calculate injury and value of damages. In this model, fishery stock changes from injuries and resulting changes in user participation are not treated as dynamic. If true stock growth and re‐growth are indeed dynamic, then the Type A model is likely underestimating fishery losses. The purpose of this paper is to illustrate the potential for such underestimation by comparing simulated stock and harvest losses under dynamic treatment and a static treatment that more closely represents the way stock and service losses are estimated under the current NRDA process.     

ALTERNATIVE METHODS TO ANALYZE THE RANK ORDERED DATA: A CASE OF INVASIVE SPECIES CONTROL

ABSTRACT. Data collected regarding homeowner preferences for various Formosan Subterranean termite control methods were analyzed using ordered probit and exploded logit models. Ordered probit model for first, second and fourth preferences had similar variables significant, although the first preference model had many significant variables. The most important variable, in terms of significance, across all preferences was the perception that a respondent thinks that termite existence is a problem in their neighborhood. The results from the exploded logit model indicated that a control option with liquid treatment option and more visits by a pest control agency is a less preferred treatment option. This paper was presented at the 2004 Research Modeling Association World Conference on Natural Resource Modeling in Melbourne, Australia.     

Characterization of the [Xtilde] 1Σ+ à 3Π and à 1Π electronic states of BBO

The three lowest-lying electronic states, [Xtilde] ¹Σ⁺, à ³II and à ¹II, of the linear BBO molecule have been systematically investigated using ab initio electronic structure theory. The equilibrium structures and physical properties including dipole moments, vibrational frequencies and associated infrared intensities, Renner parameters and energetics for the three states of BBO have been determined employing SCF, CISD, CCSD and CCSD(T) levels of theory and a wide range of basis sets. The ground state of BBO presents a degenerate real bending frequency, while the à ³II and à ¹II states show two distinct real bending frequencies due to the Renner-Teller interaction. The bending motion of the à ¹II state was analysed using the equation-of-motion (EOM)-CCSD and EOM-CC3 techniques in order to avoid possible variational collapse to a lower-lying state. The [Xtilde] ¹Σ⁺-à ³II separation was predicted to be T ₀ = 16.6 kcal mol^?1 (5800 cm^?1, 0.719 eV) at the cc-pVQZ CCSD(T) level of theory. With the cc-pVQZ EOM-CC3 method the [Xtilde] ¹Σ⁺-à ¹II splitting was predicted to be T ₀ = 48.0 kcal mol^?1 (16 800 cm^?1, 2.08 eV), which is in good agreement with the experimental value of T ⁰ = 46.6 kcal mol^?1 (16 300 cm^?1, 2.02 eV). The Renner parameters and averaged harmonic frequencies of the bending mode were determined to be ? = 0.184 and ω₂ = 363 cm^?1 for the à ³II state, and ? = 0.246 and ω₂ = 383cm^?1 for the à ¹II state. The theoretical [Xtilde] ¹Σ⁺ state harmonic B-B stretching frequency ω₃ = 636 cm^?1 is somewhat higher than the experimental estimate of 582 cm^?1 and the predicted à ¹II state harmonic B-B stretching frequency ω₃ = 861 cm^?1 is significantly higher than the experimental estimate of 440 cm^?1     

A CC2 dielectric continuum model and a CC2 molecular mechanics model

In this paper we present theory and applications for the second-order approximate singles and doubles coupled cluster (CC2) electronic structure method coupled to either a dielectric continuum (the CC2/DC model) or a molecular mechanical intermolecular force field (the CC2/MM model). Calculations of the interaction energy, solvation energy, electric dipole moment and electric quadrupole moment of liquid water are presented using the correlated CC2 approach. The results are compared to the corresponding results using the uncorrelated Hartree-Fock (HF) and the correlated coupled cluster singles and doubles (CCSD) methods. Also, a hierarchy in the coupling between the quantum mechanical (QM) and the molecular mechanical (MM) part of the system is investigated in the QM/MM model for the three different electronic structure methods.     

The QM/MM approach for wavefunctions,energies and response functions within self-consistent field and coupled cluster theories

This paper presents the coupled cluster/molecular mechanics (CC/MM) and self-consistent field/molecular mechanics (SCF/MM) approaches for wavefunctions, energies and response properties. Two physically different theories are derived, the mean-field and the direct-field interaction approaches, together with expressions for the optimization condition of both variational and non-variational wavefunctions and energies. Also derived are the linear response functions at the CC/MM and SCF/MM levels of theory, and the expressions are compared with the vacuum response functions.     

Reorientation behaviour of bent core molecules in response to an external electric field as detected by time-resolved FTIR spectroscopy

Time-resolved polarized Fourier transform infrared spectroscopy (FTIR) is employed to analyse the segmental orientation and mobility of achiral bent core molecules in response to an external electric field. By shearing the substance between ITO coated CaF2 windows two types of domain, racemic and homochiral, are formed in the high temperature B2 phase. Each of these domains is characterized by two spontaneous symmetry-breaking instabilities which yield a symmetric and an antisymmetric electro-optical response, respectively. Taking advantage of the specificity of IR spectroscopy, this switching behaviour is analysed on a molecular level for the moieties of the bent core liquid crystal materials. In this way, the electrically induced reorientation of the different segments on a cone and the suppression of the antiferroelectric structure at higher frequencies can be followed in detail. Furthermore the biased rotation of the two carbonyl groups around the molecular long axis is determined. It is shown that all molecular units move synchronously on the time scale of the experiment (10mus).     

Attosecond-correlated dynamics of two electrons in argon

In this work we explored strong field-induced decay of doubly excited transient Coulomb complex Ar ^?? → Ar ²⁺ + 2e. We measured the correlated two-electron emission as a function of carrier envelop phase (CEP) of 6 fs pulses in the non-sequential double ionization (NSDI) of argon. Classical model calculations suggest that the intermediate doubly excited Coulomb complex loses memory of its formation dynamics. We estimated the ionization time difference between the two electrons from NSDI of argon and it is 200 ± 100 as (N Camus et al, Phys. Rev. Lett. 108, 073003 (2012)).