Mirror effect induced by the dilaton field on the Hawking radiation

We discuss the string creation in the near-extremal NS1 black string solution. The string creation is described by an effective field equation derived from a fundamental string action coupled to the dilaton field in a conformally invariant manner. In the non-critical string model the dilaton field causes a timelike mirror surface outside the horizon when the size of the black string is comparable to the Planck scale. Since the fundamental strings are reflected by the mirror surface, the negative energy flux does not propagate across the surface. This means that the evaporation stops just before the naked singularity of the extremal black string appears even though the surface gravity is non-zero in the extremal limit.Comment: 15 page

Characterisation of polymorphic microsatellite loci for the bryozoan Fredericella sultana, the primary host of the causative agent of salmonid proliferative kidney disease

0000-0001-7279-715X© Springer Science+Business Media Dordrecht 2014. The attached document is the authors' final accepted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it

Vortex lattice for a holographic superconductor

We investigate the vortex lattice solution in a (2+1)-dimensional holographic model of superconductors constructed from a charged scalar condensate. The solution is obtained perturbatively near the second-order phase transition and is a holographic realization of the Abrikosov lattice. Below a critical value of magnetic field, the solution has a lower free energy than the normal state. Both the free energy density and the superconducting current are expressed by nonlocal functions, but they reduce to the expressions in the Ginzburg-Landau (GL) theory at long wavelength. As a result, a triangular lattice becomes the most favorable solution thermodynamically as in the GL theory of type II superconductors.Comment: v2: minor changes, references added; 11 pages, 2 figures: version to appear in PR

Galaxy types in the Sloan Digital Sky Survey using supervised artificial neural networks

Supervised artificial neural networks are used to predict useful properties of galaxies in the Sloan Digital Sky Survey, in this instance morphological classifications, spectral types and redshifts. By giving the trained networks unseen data, it is found that correlations between predicted and actual properties are around 0.9 with rms errors of order ten per cent. Thus, given a representative training set, these properties may be reliably estimated for galaxies in the survey for which there are no spectra and without human intervention

Photogenerated Carriers in SrTiO3 Probed by Mid-Infrared Absorption

Infrared absorption spectra of SrTiO$_3$ have been measured under above-band-gap photoexcitations to study the properties of photogenerated carriers, which should play important roles in previously reported photoinduced phenomena in SrTiO$_3$. A broad absorption band appears over the entire mid-infrared region under photoexcitation. Detailed energy, temperature, and excitation power dependences of the photoinduced absorption are reported. This photo-induced absorption is attributed to the intragap excitations of the photogenerated carriers. The data show the existence of a high density of in-gap states for the photocarriers, which extends over a wide energy range starting from the conduction and valence band edges.Comment: 5 pages, 5 figures, submitted to J. Phys. Soc. Jp

Carbon in Spiral Galaxies from Hubble Space Telescope Spectroscopy

We present measurements of the gas-phase C/O abundance ratio in six H II regions in the spiral galaxies M101 and NGC 2403, based on ultraviolet spectroscopy using the Faint Object Spectrograph on the Hubble Space Telescope. The C/O ratios increase systematically with O/H in both galaxies, from log C/O approximately -0.8 at log O/H = -4.0 to log C/O approx. -0.1 at log O/H = -3.4. C/N shows no correlation with O/H. The rate of increase of C/O is somewhat uncertain because of uncertainty as to the appropriate UV reddening law, and uncertainty in the metallicity dependence on grain depletions. However, the trend of increasing C/O with O/H is clear, confirming and extending the trend in C/O indicated previously from observations of irregular galaxies. Our data indicate that the radial gradients in C/H across spiral galaxies are steeper than the gradients in O/H. Comparing the data to chemical evolution models for spiral galaxies shows that models in which the massive star yields do not vary with metallicity predict radial C/O gradients that are much flatter than the observed gradients. The most likely hypothesis at present is that stellar winds in massive stars have an important effect on the yields and thus on the evolution of carbon and oxygen abundances. C/O and N/O abundance ratios in the outer disks of spirals determined to date are very similar to those in dwarf irregular galaxies. This implies that the outer disks of spirals have average stellar population ages much younger than the inner disks.Comment: 38 pages, 9 postscript figures, uses aaspp4.sty. Accepted for publication in The Astrophysical Journa

Sex and outcrossing in a sessile freshwater invertebrate

SUMMARY1. The freshwater bryozoan Cristatella mucedo, in common with other sessile, benthic freshwater taxa, has an unusual life history: sex occurs during a relatively brief period near the start of the growing season, and overwintering occurs in the form of asexually produced dormant propagules (statoblasts). Consistent observed heterozygosity (Ho) deficits in C. mucedo populations have previously suggested that inbreeding is common, although a possible contribution of a Wahlund effect to low Ho could not be discounted. 2. We have used microsatellite data in the first study based on codominant markers to genetically characterise maternal colonies and larval offspring of C. mucedo. The 'population' represented by the larvae was in Hardy–Weinberg equilibrium, which has previously been found in only one of 39 populations of C. mucedo. At least 64% of larvae were the products of outcrossing. We suggest that the unusual early timing of sex may be a strategy to maximise rates of outcrossing within populations of sessile freshwater invertebrate