Phylogeography, population structure and evolution of coral-eating butterflyfishes (Family Chaetodontidae, genus Chaetodon, subgenus Corallochaetodon)

Aim: This study compares the phylogeography, population structure and evolution of four butterflyfish species in the Chaetodon subgenus Corallochaetodon, with two widespread species (Indian Ocean – C. trifasciatus and Pacific Ocean – C. lunulatus), and two species that are largely restricted to the Red Sea (C. austriacus) and north-western (NW) Indian Ocean (C. melapterus). Through extensive geographical coverage of these taxa, we seek to resolve patterns of genetic diversity within and between closely related butterflyfish species in order to illuminate biogeographical and evolutionary processes. Location: Red Sea, Indian Ocean and Pacific Ocean. Methods: A total of 632 individuals from 24 locations throughout the geographical ranges of all four members of the subgenus Corallochaetodon were sequenced using a 605 bp fragment (cytochrome b) of mtDNA. In addition, 10 microsatellite loci were used to assess population structure in the two widespread species. Results: Phylogenetic reconstruction indicates that the Pacific Ocean C. lunulatus diverged from the Indian Ocean C. trifasciatus approximately 3 Ma, while C. melapterus and C. austriacus comprise a cluster of shared haplotypes derived from C. trifasciatus within the last 0.75 Myr. The Pacific C. lunulatus had significant population structure at peripheral locations on the eastern edge of its range (French Polynesia, Johnston Atoll, Hawai'i), and a strong break between two ecoregions of the Hawaiian Archipelago. The Indian Ocean C. trifasciatus showed significant structure only at the Chagos Archipelago in the central Indian Ocean, and the two range-restricted species showed no population structure but evidence of recent population expansion. Main conclusions: Patterns of endemism and genetic diversity in Corallochaetodon butterflyfishes have been shaped by (1) Plio-Pleistocene sea level changes that facilitated evolutionary divergences at biogeographical barriers between Indian and Pacific Oceans, and the Indian Ocean and Red Sea, and (2) semi-permeable oceanographic and ecological barriers working on a shorter time-scale. The evolution of range-restricted species (Red Sea and NW Indian Ocean) and isolated populations (Hawai'i) at peripheral biogeographical provinces indicates that these areas are evolutionary incubators for reef fishes

A review of the goatfishes of the genus Upeneus (Perciformes : Mullidae) from New Caledonia and the Chesterfield Bank, with a new species and four new records

A review of the goatfishes of the genus Upeneus (Perciformes: Mullidae) from New Caledonia and the Chesterfield Bank, with a new species and four new records. Zoological Studies 45(3): 298-307. Only 2 species of the goatfish genus Upeneus have been recorded from New Caledonia: U. tragula Richardson and U. vittatus (Forsskal). Upeneus filifer (Ogilby) was listed by name only in a report on experimental trawling on the Chesterfield Bank. New records are herein reported of U. australiae Kim and Nakaya, U. guttatus (Day), U. moluccensis (Bleeker), and U. sulphurus Cuvier for the New Caledonia region, and U. mouthami is described as a new species. A key, diagnoses, and color illustrations are given for all 8 species; summary notes on food habits are provided

Stochastic emergence of inflaton fluctuations in a SdS primordial universe with large-scale repulsive gravity from a 5D vacuum

We develop a stochastic approach to study scalar field fluctuations of the inflaton field in an early inflationary universe with a black-hole (BH), which is described by an effective 4D SdS metric. Considering a 5D Ricci-flat SdS static metric, we implement a planar coordinate transformation, in order to obtain a 5D cosmological metric, from which the effective 4D SdS metric can be induced on a 4D hypersurface. We found that at the end of inflation, the squared fluctuations of the inflaton field are not exactly scale independent and becomes sensitive with the mass of the BH.Comment: version accepted in European Physical Journal Plu

On the thin-shell limit of branes in the presence of Gauss-Bonnet interactions

In this paper we study thick-shell braneworld models in the presence of a Gauss-Bonnet term. We discuss the peculiarities of the attainment of the thin-shell limit in this case and compare them with the same situation in Einstein gravity. We describe the two simplest families of thick-brane models (parametrized by the shell thickness) one can think of. In the thin-shell limit, one family is characterized by the constancy of its internal density profile (a simple structure for the matter sector) and the other by the constancy of its internal curvature scalar (a simple structure for the geometric sector). We find that these two families are actually equivalent in Einstein gravity and that the presence of the Gauss-Bonnet term breaks this equivalence. In the second case, a shell will always keep some non-trivial internal structure, either on the matter or on the geometric sectors, even in the thin-shell limit.Comment: 17 pages, 2 figures, RevTeX 4. Revised version accepted for publication in Physical Review

Power-Law Inflation from the Rolling Tachyon

Modeling the potential by an inverse square law in terms of the tachyon field ($V(T)=\beta T^{-2}$) we find exact solution for spatially flat isotropic universe.We show that for $\beta>2\sqrt{3}/3$ the model undergoes power-law inflation. A way to construct other exact solutions is specified and exemplified.Comment: References added. Matches the version in print. To appear in PR

Realistic Tunneling States for the Magnetic Effects in Non-Metallic Real Glasses

The discovery of magnetic and compositional effects in the low temperature properties of multi-component glasses has prompted the need to extend the standard two-level systems (2LSs) tunneling model. A possible extension \cite{Jug2004} assumes that a subset of tunneling quasi-particles is moving in a three-welled potential (TWP) associated with the ubiquitous inhomogeneities of the disordered atomic structure of the glass. We show that within an alternative, cellular description of the intermediate-range atomic structure of glasses the tunneling TWP can be fully justified. We then review how the experimentally discovered magnetic effects can be explained within the approach where only localized atomistic tunneling 2LSs and quasi-particles tunneling in TWPs are allowed. We discuss the origin of the magnetic effects in the heat capacity, dielectric constant (real and imaginary parts), polarization echo and SQUID magnetization in several glassy systems. We conclude by commenting on a strategy to reveal the mentioned tunneling states (2LSs and TWPs) by means of atomistic computer simulations and discuss the microscopic nature of the tunneling states in the context of the potential energy landscape of glass-forming systems.Comment: 48 pages, 27 figures; mini-review for the Proceedings of the XIV International Workshop on Complex Systems (Fai della Paganella, Trento, March 2015) (submitted to Phil.Mag.). arXiv admin note: text overlap with arXiv:cond-mat/0210221 by other author

La campagne CORAIL 1 du "N.O. CORIOLIS" aux îles Chesterfield (du 15 août au 4 septembre 1988) : données préliminaires sur les peuplements ichtyologiques

La campagne CORAIL 1 a permis l'étude des peuplements ichtyologiques coralliens sur trois stations aux îles Chesterfield. Chaque station est divisée en trois strates de profondeur : 0-5 m, 5-10 m et 10-15 m. Dans chaque strate deux empoisonnements à la roténone et de 3 à 5 transects ont été réalisés. Au total, 555 espèces de poissons ont été recensées. Ces poissons présentent une affinité légérement supérieure avec les peuplements de Nouvelle Calédonie qu'avec ceux de la Grande Barrière de Corail (GBR). Les résultats des empoisonnements et des comptages ont été combinés pour calculer les densités et les biomasses. Ces deux paramètres diminuent avec la profondeur, mais du fait de la diminution simultanée des substrats durs avec la profondeur, on observe de très grandes concentrations de poissons sur les pâtés coralliens isolés sur les fonds meubles au-delà de 10 m. Les densités et les biomasses observées (O.15 à 5.26 poissons/m2 et de 1.7 à 230 g/m2) sont du même ordre de grandeur que ce qui est actuellement connu du Pacifique tropical. La structure trophique de ces peuplements varie considérablement d'une strate à l'autre, l'élément le plus stable étant le nombre d'espèces par groupe trophiqu

A 5D non compact and non Ricci flat Kaluza-Klein Cosmology

A model universe is proposed in the framework of 5-dimensional noncompact Kaluza-Klein cosmology which is not Ricci flat. The 4D part as the Robertson-Walker metric is coupled to conventional perfect fluid, and its extra-dimensional part is coupled to a dark pressure through a scalar field. It is shown that neither early inflation nor current acceleration of the 4D universe would happen if the non-vacuum states of the scalar field would contribute to 4D cosmology.Comment: 13 pages, major revision, published online in GR