Habitat-dependent outdoor recreation and conservation organizations can enable recreational fishers to contribute to conservation of coastal marine ecosystems

Stakeholder engagement is essential to conserve ecosystems and associated biodiversity. Outdoor recreation specialists represent stakeholder groups that often rely on specific healthy ecosystems and have unique incentives to contribute to conservation and stewardship. We introduce the concept of habitat-dependent outdoor recreation conservation organizations (HDORCOs) and their potential to harness outdoor recreation enthusiasm to achieve ecosystem-scale conservation objectives. We identify potential roles for HDORCOs in nurturing pro-environmental attitudes and facilitating stewardship behavior among recreationists, focusing on examples from recreational fishing specialists and coastal marine ecosystems. While HDORCOs have achieved conservation outcomes in a range of settings, transferability across recreational specializations and ecological, cultural, socioeconomic, and governance contexts could remain challenging and potentially requires further development of the HDORCO concept. Communication with HDORCOs is one strategy to enhance engagement of recreationists, stakeholder groups not traditionally associated with pro-environmental behavior, in ecosystem-scale conservation efforts

Soft-core baryon-baryon potentials for the complete baryon octet

SU(3) symmetry relations on the recently constructed hyperon-nucleon potentials are used to develop potential models for all possible baryon-baryon interaction channels. The main focus is on the interaction channels with total strangeness S=-2, -3, and -4, for which no experimental data exist yet. The potential models for these channels are based on SU(3) extensions of potential models for the S=0 and S=-1 sectors, which are fitted to experimental data. Although the SU(3) symmetry is not taken to be exact, the S=0 and S=-1 sectors still provide the necessary constraints to fix all free parameters. The potentials for the S=-2, -3, and -4 sectors, therefore, do not contain any additional free parameters, which makes them the first models of this kind. Various properties of the potentials are illustrated by giving results for scattering lengths, bound states, and total cross sections.Comment: 22 pages RevTex, 6 postscript figure

Relative sea-level change in Newfoundland, Canada during the past ∼3000 years

Several processes contributing to coastal relative sea-level (RSL) change in the North Atlantic Ocean are observed and/or predicted to have distinctive spatial expressions that vary by latitude. To expand the latitudinal range of RSL records spanning the past ∼3000 years and the likelihood of recognizing the characteristic fingerprints of these processes, we reconstructed RSL at two sites (Big River and Placentia) in Newfoundland from salt-marsh sediment. Bayesian transfer functions established the height of former sea level from preserved assemblages of foraminifera and testate amoebae. Age-depth models constrained by radiocarbon dates and chronohorizons estimated the timing of sediment deposition. During the past ∼3000 years, RSL rose by ∼3.0 m at Big River and by ∼1.5 m at Placentia. A locally calibrated geotechnical model showed that post-depositional lowering through sediment compaction was minimal. To isolate and quantify contributions to RSL from global, regional linear, regional non-linear, and local-scale processes, we decomposed the new reconstructions (and those in an expanded, global database) using a spatio-temporal statistical model. The global component confirms that 20th century sea-level rise occurred at the fastest, century-scale rate in over 3000 years (P > 0.999). Distinguishing the contributions from local and regional non-linear processes is made challenging by a sparse network of reconstructions. However, only a small contribution from local-scale processes is necessary to reconcile RSL reconstructions and modeled RSL trends. We identified three latitudinally-organized groups of sites that share coherent regional non-linear trends and indicate that dynamic redistribution of ocean mass by currents and/or winds was likely an important driver of sea-level change in the North Atlantic Ocean during the past ∼3000 years

Glueball spectrum based on a rigorous three-dimensional relativistic equation for two-gluon bound states I: Derivation of the relativistic equation

A rigorous three-dimensional relativistic equation satisfied by two-gluon bound states is derived from the QCD with massive gluons. With the gluon fields and the quark fields being expanded in terms of the gluon multipole fields and the spherical Dirac spinors respectively, the equation is well established in the angular momentum representation and hence is much convenient for solving the problem of two-gluon glueball spectra. In particular, the interaction kernel in the equation is exactly derived and given a closed expression which includes all the interactions taking place in the two-gluon glueballs. The kernel contains only a few types of Green's functions and commutators. Therefore, it is not only easily calculated by the perturbation method, but also provides a suitable basis for nonperturbative investigations

Glueball spectrum based on a rigorous three-dimensional relativistic equation for two-gluon bound states II: calculation of the glueball spectrum

In the preceding paper, a rigorous three-dimensional relativistic equation for two-gluon bound states was derived from the QCD with massive gluons and represented in the angular momentum representation. In order to apply this equation to calculate the glueball spectrum, in this paper, the equation is recast in an equivalent three-dimensional relativistic equation satisfied by the two-gluon positive energy state amplitude. The interaction Hamiltonian in the equation is exactly derived and expressed as a perturbative series. The first term in the series describes the one-gluon exchange interaction which includes fully the retardation effect in it. This term plus the linear confining potential are chosen to be the interaction Hamiltonian and employed in the practical calculation. With the integrals containing three and four spherical Bessel functions in the QCD vertices being analytically calculated, the interaction Hamiltonian is given an explicit expression in the angular momentum representation. Numerically solving the relativistic equation with taking the contributions arising from the retardation effect and the longitudinal mode of gluon fields into account, a set of masses for the $0^{++},0^{-+},1^{++},1^{-+},2^{++}$ and $2^{-+\text{}}$ glueball states are obtained and are in fairly good agreement with the predictions given by the lattice simulatio

Parity violating target asymmetry in electron - proton scattering

We analyze the parity-violating (PV) components of the analyzing power in elastic electron-proton scattering and discuss their sensitivity to the strange quark contributions to the proton weak form factors. We point out that the component of the analyzing power along the momentum transfer is independent of the electric weak form factor and thus compares favorably with the PV beam asymmetry for a determination of the strangeness magnetic moment. We also show that the transverse component could be used for constraining the strangeness radius. Finally, we argue that a measurement of both components could give experimental information on the strangeness axial charge.Comment: 24 pages, Latex, 5 eps figures, submitted to Phys.Rev.

Sum rule for the backward spin polarizability of the nucleon from a backward dispersion relation

A new sum rule for $\gamma_\pi$, the backward spin polarizability of the nucleon, is derived from a backward-angle dispersion relation. Taking into account single- and multi-pion photoproduction in the s-channel up to the energy 1.5 GeV and resonances in the t-channel with mass below 1.5 GeV, it is found for the proton and neutron that $[\gamma_\pi]_p$ = -39.5 +/- 2.4 and $[\gamma_\pi]_n$ = 52.5 +/- 2.4, respectively, in units of 10^{-4} fm^4.Comment: 10 pages, 1 figure, revtex. Submitted to Phys. Lett.

Deuteron Electroweak Disintegration

We study the deuteron electrodisintegration with inclusion of the neutral currents focusing on the helicity asymmetry of the exclusive cross section in coplanar geometry. We stress that a measurement of this asymmetry in the quasi elastic region is of interest for an experimental determination of the weak form factors of the nucleon, allowing one to obtain the parity violating electron neutron asymmetry. Numerically, we consider the reaction at low momentum transfer and discuss the sensitivity of the helicity asymmetry to the strangeness radius and magnetic moment. The problems coming from the finite angular acceptance of the spectrometers are also considered.Comment: 30 pages, Latex, 7 eps figures, submitted to Phys.Rev.C e-mail: [email protected] , [email protected]

Density functional study of Aun_n (n=2-20) clusters: lowest-energy structures and electronic properties

We have investigated the lowest-energy structures and electronic properties of the Au$_n$(n=2-20) clusters based on density functional theory (DFT) with local density approximation. The small Au$_n$ clusters adopt planar structures up to n=6. Tabular cage structures are preferred in the range of n=10-14 and a structural transition from tabular cage-like structure to compact near-spherical structure is found around n=15. The most stable configurations obtained for Au$_{13}$ and Au$_{19}$ clusters are amorphous instead of icosahedral or fcc-like, while the electronic density of states sensitively depend on the cluster geometry. Dramatic odd-even alternative behaviors are obtained in the relative stability, HOMO-LUMO gaps and ionization potentials of gold clusters. The size evolution of electronic properties is discussed and the theoretical ionization potentials of Au$_n$ clusters compare well with experiments.Comment: 6 pages, 7 figure