Regularizing the quark-level σ\sigma model

We show that the finite difference, $-i\pi^2 m^2$, between quadratic and logarithmic divergent integrals $\int d^4p[m^2(p^2-m^2)^{-2}-(p^2-m^2)^{-1}]$, as encountered in the linear $\sigma$ model, is in fact regularization independent.Comment: 9 pages, 2 figures, Latex, to appear in Mod. Phys. Lett.

Embryonic and post-embryonic development of the polyclad flatworm Maritigrella crozieri; implications for the evolution of spiralian life history traits

<p>Abstract</p> <p>Background</p> <p>Planktonic life history stages of spiralians share some muscular, nervous and ciliary system characters in common. The distribution of these characters is patchy and can be interpreted either as the result of convergent evolution, or as the retention of primitive spiralian larval features. To understand the evolution of these characters adequate taxon sampling across the Spiralia is necessary. Polyclad flatworms are the only free-living Platyhelminthes that exhibit a continuum of developmental modes, with direct development at one extreme, and indirect development via a trochophore-like larval stage at the other. Here I present embryological and larval anatomical data from the indirect developing polyclad <it>Maritrigrella crozieri</it>, and consider these data within a comparative spiralian context.</p> <p>Results</p> <p>After 196 h hours of embryonic development, <it>M. crozieri </it>hatches as a swimming, planktotrophic larva. Larval myoanatomy consists of an orthogonal grid of circular and longitudinal body wall muscles plus parenchymal muscles. Diagonal body wall muscles develop over the planktonic period. Larval neuroanatomy consists of an apical plate, neuropile, paired nerve cords, a peri-oral nerve ring, a medial nerve, a ciliary band nerve net and putative ciliary photoreceptors. Apical neural elements develop first followed by posterior perikarya and later pharyngeal neural elements. The ciliated larva is encircled by a continuous, pre-oral band of longer cilia, which follows the distal margins of the lobes; it also possesses distinct apical and caudal cilia.</p> <p>Conclusions</p> <p>Within polyclads heterochronic shifts in the development of diagonal bodywall and pharyngeal muscles are correlated with life history strategies and feeding requirements. In contrast to many spiralians, <it>M. crozieri </it>hatch with well developed nervous and muscular systems. Comparisons of the ciliary bands and apical organs amongst spiralian planktonic life-stages reveal differences; <it>M. crozieri </it>lack a distinct ciliary band muscle and flask-shaped epidermal serotonergic cells of the apical organ. Based on current phylogenies, the distribution of ciliary bands and apical organs between polyclads and other spiralians is not congruent with a hypothesis of homology. However, some similarities exist, and this study sets an anatomical framework from which to investigate cellular and molecular mechanisms that will help to distinguish between parallelism, convergence and homology of these features.</p

Neutral pion decay in dense skyrmion matter

We study the density dependence of the decay $\pi^0\to \gamma \gamma$ using the Skyrme Lagrangian to describe simultaneously both the matter background and mesonic fluctuations. Pion properties such as mass and decay constant are modified by the medium. This leads to large suppression at high density of both photo-production from the neutral pion and the reverse process. The in-medium effective charge of $\pi^{\pm}$ are also discussed in the same framework.Comment: 8 pages, 4 figures. Corrections in light of referee comment

A Survey of the Subsistence and Artisanal Fisheries in Rural Areas of Viti Levu, Fiji

Resource /Energy Economics and Policy,

Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography

Acknowledgments We thank Mallory Young for providing phase velocity measurements in mainland Australia and Tasmania. Robert Musgrave is thanked for making available his tilt-filtered magnetic intensity map. In the short term, data may be made available by contacting the authors (S.P. or N.R.). A new database of passive seismic data recorded in Australia is planned as part of a national geophysics data facility for easy access download. Details on the status of this database may be obtained from the authors (S.P., N.R., or A.M.R.). There are no restrictions on access for noncommercial use. Commercial users should seek written permission from the authors (S.P. or N.R.). Ross Cayley publishes with the permission of the Director of the Geological Survey of Victoria.Peer reviewedPublisher PD

Evidence of micro-continent entrainment during crustal accretion

Peer reviewedPublisher PD

Development and application of the GIM code for the Cyber 203 computer

The GIM computer code for fluid dynamics research was developed. Enhancement of the computer code, implicit algorithm development, turbulence model implementation, chemistry model development, interactive input module coding and wing/body flowfield computation are described. The GIM quasi-parabolic code development was completed, and the code used to compute a number of example cases. Turbulence models, algebraic and differential equations, were added to the basic viscous code. An equilibrium reacting chemistry model and implicit finite difference scheme were also added. Development was completed on the interactive module for generating the input data for GIM. Solutions for inviscid hypersonic flow over a wing/body configuration are also presented

A Review of Peer Support for Suicide Bereavement as a Postvention Alternative

Peer support is acknowledged as a cornerstone in recovery from mental illness and addictions; yet its applicability for survivors of suicide has not been explored. Most postvention programs consist of professionally led individual and group counseling services. Alternatives to traditional professional counseling interventions are reported in the mental health peer support literature. We examine the postvention literature and the related mental health literature on peer support programs to determine their relevance and applicability. This report considers peer support provided as a postvention option or supplied in tandem with conventional professional services. Finally, we examine this as an intervention that also needs to be documented by quantitative and qualitative methods so that the presumptions and hesitations about its efficaciousness with suicide survivors can be documented

THE BIOMASS OF TROPICAL ANCHOVIES (Encrasicholina SPECIES) AT BACAN, EASTERN INDONESIA ESTIMATED BY THE DAILY EGG PRODUCTION METHOD

Tropical anchovies (Encrasicholdno species) are the target of the large baitfishery for the pole-and-line skipjack tuna fleet in eastern Indonesia. Recent studies have shown that the tuna catches are constrained by a lack of bait