Radiation constraints from cosmic strings

We show that it is possible to evolve a network of global strings numerically including the effects of radiative backreaction, using the renormalised equations for the Kalb-Ramond action. We calculate radiative corrections to the equations of motion and deduce the effect on a network of global strings. We also discuss the implications of this work for the cosmological axion density.Comment: 4 Pages, UUencoded postscript file, to appear in 'Trends in Astro-Particle Physics - Nuclear Physics B, Proceedings Supplement

Pilbarana, a new subterranean amphipod genus (Hadzioidea: Eriopisidae) of environmental assessment importance from the Pilbara, Western Australia

The Pilbara and nearby regions in north-western Western Australia have an exceptionally high diversity of short-range endemic invertebrates inhabiting threatened groundwater-dependent habitats. Amphipod crustaceans, in particular, are dominant in these communities, but are poorly understood taxonomically, with many undescribed species. Recent molecular phylogenetic analyses of Pilbara eriopisid amphipods have, nonetheless, uncovered a previously unknown biodiversity. In this study, we formally establish a new genus, Pilbarana Stringer & King gen. nov., and describe two new species, P. grandis Stringer & King sp. nov. from Cane River Conservation Park and P. lowryi Stringer & King sp. nov. from the Fortescue River Basin near the Hamersley Range, using a combination of molecular and morphological data. The new genus is similar morphologically to the two additional Western Australian eriopisid genera, Nedsia Barnard & Williams, 1995 and Norcapensis Bradbury & Williams, 1997, but represents a genetically divergent, reciprocally monophyletic lineage, which can be differentiated by its vermiform body shape, the presence of an antennal sinus, and by the length and form of the antennae and uropods. This research signifies an important contribution to knowledge of Pilbara subterranean communities and has critical implications for future environmental impact assessments and conservation management.Danielle N. Stringer, Rachael A. King, Andrew D. Austin, Michelle T. Guzi

On the gravitational, dilatonic and axionic radiative damping of cosmic strings

We study the radiation reaction on cosmic strings due to the emission of dilatonic, gravitational and axionic waves. After verifying the (on average) conservative nature of the time-symmetric self-interactions, we concentrate on the finite radiation damping force associated with the half-retarded minus half-advanced ``reactive'' fields. We revisit a recent proposal of using a ``local back reaction approximation'' for the reactive fields. Using dimensional continuation as convenient technical tool, we find, contrary to previous claims, that this proposal leads to antidamping in the case of the axionic field, and to zero (integrated) damping in the case of the gravitational field. One gets normal positive damping only in the case of the dilatonic field. We propose to use a suitably modified version of the local dilatonic radiation reaction as a substitute for the exact (non-local) gravitational radiation reaction. The incorporation of such a local approximation to gravitational radiation reaction should allow one to complete, in a computationally non-intensive way, string network simulations and to give better estimates of the amount and spectrum of gravitational radiation emitted by a cosmologically evolving network of massive strings.Comment: 48 pages, RevTex, epsfig, 1 figure; clarification of the domain of validity of the perturbative derivation of the string equations of motion, and of their renormalizabilit

Finite temperature effects in Coulomb blockade quantum dots and signatures of spectral scrambling

The conductance in Coulomb blockade quantum dots exhibits sharp peaks whose spacings fluctuate with the number of electrons. We derive the temperature-dependence of these fluctuations in the statistical regime and compare with recent experimental results. The scrambling due to Coulomb interactions of the single-particle spectrum with the addition of an electron to the dot is shown to affect the temperature-dependence of the peak spacing fluctuations. Spectral scrambling also leads to saturation in the temperature dependence of the peak-to-peak correlator, in agreement with recent experimental results. The signatures of scrambling are derived using discrete Gaussian processes, which generalize the Gaussian ensembles of random matrices to systems that depend on a discrete parameter -- in this case, the number of electrons in the dot.Comment: 14 pages, 4 eps figures included, RevTe

Fivebranes and 4-manifolds

We describe rules for building 2d theories labeled by 4-manifolds. Using the proposed dictionary between building blocks of 4-manifolds and 2d N=(0,2) theories, we obtain a number of results, which include new 3d N=2 theories T[M_3] associated with rational homology spheres and new results for Vafa-Witten partition functions on 4-manifolds. In particular, we point out that the gluing measure for the latter is precisely the superconformal index of 2d (0,2) vector multiplet and relate the basic building blocks with coset branching functions. We also offer a new look at the fusion of defect lines / walls, and a physical interpretation of the 4d and 3d Kirby calculus as dualities of 2d N=(0,2) theories and 3d N=2 theories, respectivelyComment: 81 pages, 18 figures. v2: misprints corrected, clarifications and references added. v3: additions and corrections about lens space theory, 4-manifold gluing, smooth structure

Trajectories of university adjustment in the United Kingdom: Emotion management and emotional self-efficacy protect against initial poor adjustment

Little is known about individual differences in the pattern of university adjustment. This study explored longitudinal associations between emotional self-efficacy, emotion management, university adjustment, and academic achievement in a sample of first year undergraduates in the United Kingdom (N=331). Students completed measures of adjustment to university at three points during their first year at university. Latent Growth Mixture Modeling identified four trajectories of adjustment: (1) low, stable adjustment, (2) medium, stable adjustment, (3) high, stable adjustment, and (4) low, increasing adjustment. Membership of the low, stable adjustment group was predicted by low emotional self-efficacy and low emotion management scores, measured at entry into university. This group also had increased odds of poor academic achievement, even when grade at entry to university was controlled. Students who increased in adjustment had high levels of emotion management and emotional self-efficacy, which helped adaptation. These findings have implications for intervention

Integrating spectrophotometric and XRD analyses in the investigation of burned dental remains

Heat alters colour and crystallinity of teeth by destruction of the organic content and inducing hydroxyapatite crystal growth. The colour and crystallite changes can be quantified using spectrophotometric and x-ray diffraction analyses, however these analyses are not commonly used in combination to evaluate burned dental remains. In this study, thirty-nine teeth were incinerated at 300–1000 °C for 15 and 30 min and then measured using a spectrophotometer and an x-ray diffractometer. Response variables used were lightness, L*, and chromaticity a* and b* and luminance (whiteness and yellowness) for colour, and crystal size for crystallinity. Statistical analysis to determine the attribution of these variables revealed yellowness and crystal size were significantly affected by temperature (p < 0.05), whilst duration of heat-exposure showed no significant effect. This study suggests the inclusion of both spectrophotometric and x-ray diffraction in investigating thermal-heated teeth is useful to accurately estimate the temperature teeth are exposed to.Rabiah A. Rahmata, Melissa A. Humphries, Jeremy J. Austin, Adrian M.T. Linacre, Mark Raven, Peter Sel

Universal Correlations of Coulomb Blockade Conductance Peaks and the Rotation Scaling in Quantum Dots

We show that the parametric correlations of the conductance peak amplitudes of a chaotic or weakly disordered quantum dot in the Coulomb blockade regime become universal upon an appropriate scaling of the parameter. We compute the universal forms of this correlator for both cases of conserved and broken time reversal symmetry. For a symmetric dot the correlator is independent of the details in each lead such as the number of channels and their correlation. We derive a new scaling, which we call the rotation scaling, that can be computed directly from the dot's eigenfunction rotation rate or alternatively from the conductance peak heights, and therefore does not require knowledge of the spectrum of the dot. The relation of the rotation scaling to the level velocity scaling is discussed. The exact analytic form of the conductance peak correlator is derived at short distances. We also calculate the universal distributions of the average level width velocity for various values of the scaled parameter. The universality is illustrated in an Anderson model of a disordered dot.Comment: 35 pages, RevTex, 6 Postscript figure

Energy metabolism in mobile, wild-sampled sharks inferred by plasma lipids

Evaluating how predators metabolize energy is increasingly useful for conservation physiology, as it can provide information on their current nutritional condition. However, obtaining metabolic information from mobile marine predators is inherently challenging owing to their relative rarity, cryptic nature and often wide-ranging underwater movements. Here, we investigate aspects of energy metabolism in four free-ranging shark species (n = 281; blacktip, bull, nurse, and tiger) by measuring three metabolic parameters [plasma triglycerides (TAG), free fatty acids (FFA) and cholesterol (CHOL)] via non-lethal biopsy sampling. Plasma TAG, FFA and total CHOL concentrations (in millimoles per litre) varied inter-specifically and with season, year, and shark length varied within a species. The TAG were highest in the plasma of less active

Splitting of the Dipole and Spin-Dipole Resonances

Cross sections for the 90,92,94Zr(p,n) reactions were measured at energies of 79.2 and 119.4 MeV. A phenomenological model was developed to describe the variation with bombarding energy of the position of the L=1 peak observed in these and other (p,n) reactions. The model yields the splitting between the giant dipole and giant spin dipole resonances. Values of these splittings are obtained for isotopes of Zr and Sn and for 208Pb.Comment: 14 pages, 4 figure