Deux nouveau horizons a vertebres (Chondrichthyes-Elasmobranchii et osteichthyes actinopterygii) dans le toarcien belge et limitrophe (Lorraine) synthese stratigraphique et profils nouveaux

Two new vertebrates faunas (elasmobranches, actinopterygians, reptiles) from the belgian Toarcian are introduced. A stratigraphy review of the Lorraine Toarcian is proposed

Disused Jurassic regional stage from Belgium: Virtonian

An overview of the definition and history of the Virtonian is given with the argumentation for the abandonment of this disused regional stage

Disused Jurassic regional stage from Belgium: Virtonian

An overview of the definition and history of the Virtonian is given with the argumentation for the abandonment of this disused regional stage

A note on an early Jurassic ophiuroid from Rachecourt (Lorraine, Belgium)

A fairly well-preserved ophiuroid, collected from micaceous sandy argillites of the Messaney Formation (Domerian, late Pliensbachian) as exposed at Rachecourt (Gaume, Belgian Lorraine) is described and tentatively identified as Sinosura wolburgi (Hess, 1960). The rarity of complete ophiuroid fossils in Belgian Jurassic deposits and the poor fossil content of the Messaney Formation (bioelastic beds, crinoid columnals) warrant description of the present specimen

Skyrmion and Skyrme-Black holes in de Sitter spacetime

Numerical arguments are presented for the existence of regular and black hole solutions of the Einstein-Skyrme equations with a positive cosmological constant. These classical configurations approach asymptotically the de Sitter spacetime. The main properties of the solutions and the differences with respect to the asymptotically flat ones are discussed. It particular our results suggest that, for a positive cosmological constant, the mass evaluated as timelike infinity in infinite. Special emphasis is set to De Sitter black holes Skyrmions which display two horizons.Comment: 11 pages, 4 figure

A new microvertebrate fauna from the Middle Hettangian (early Jurassic) of Fontenoille (Province of Luxembourg, south Belgium)

A Lower Jurassic horizon from Fontenoille yielding fossil fish remains can be dated to the Middle Hettangian Liasicus zone on the basis of the early belemnite Schwegleria and the ammonite Alsatites Iciqueus francus. Hybodontiform sharks are represented by Hybodus reticularis, Lissodus sp„ Polxacrodus sp, and Neoselachians by Synechodus paludinensis nov. sp. and Synechodus streitzi, nov. sp. Earlier reports of a scyliorhinid are not confirmed; teeth of similar morphology to scyliorhinids seem to be juvenile variants of 5. paludinensis. Chimaeriform remains include Squaloraja sp., the earliest occurrence of the genus. The Actinopterygian fauna is introduced, comprising a palaeonisciform cf. Ptxcholepis, a possible late perleidiform cf. Platysiagum, the dapediid semionotiforms Dapedium and cf. Tetragonolepis, the pycnodontiform Eomesodon, halecomorphs cf. Furidae or Ophiopsidae, pholidophoriforms and/or Leptolepididae, and actinistians. Lepidosaur remains are also present

Non Uniform Black Strings and Critical Dimensions in AdSdAdS_d

We study the equations of black strings in spacetimes of arbitrary dimensions with a negative cosmological constant and construct numerically non uniform black strings solutions. Our results suggest the existence of a localised black hole in asymptotically locally $AdS$ spacetime. We also present evidences for a dependence of the critical dimension on the horizon radius.The critical dimension represents the dimension where the order of the phase transition between uniform and non uniform black string changes. Finally, we argue that both, the regular asymptotically locally $AdS$ solution and $AdS$ black string solutions with a very small horizon radius, present a negative tension. This turns out to be an unexpected feature of the solutions.Comment: 13 pages, 5 figure

Charged-rotating black holes and black strings in higher dimensional Einstein-Maxwell theory with a positive cosmological constant

We present arguments for the existence of charged, rotating black holes in $d=2N+1$ dimensions, with $d\geq 5$ with a positive cosmological constant. These solutions posses both, a regular horizon and a cosmological horizon of spherical topology and have $N$ equal-magnitude angular momenta. They approach asymptotically the de Sitter spacetime background. The counterpart equations for $d=2N+2$ are investigated, by assuming that the fields are independant of the extra dimension $y$, leading to black strings solutions. These solutions are regular at the event horizon. The asymptotic form of the metric is not the de Sitter form and exhibit a naked singularity at finite proper distance.Comment: 21 pages, 9 figure

New stable phase of non uniform black strings in AdSd{AdS}_d

We consider the non uniform $AdS$ black string equations in arbitrary number of dimension in a perturbative approach up to order 2 and in a non perturbative. We restrict the study in the perturbative approach to the backreacting modes, since they provide the first relevant corrections on the thermodynamical quantities of the solutions. We also present some preliminary results in the construction of non-perturbative solutions, in particular, we present a first part of the non uniform - uniform black string phase diagram. Our results suggests the existence of a new stable phase for $AdS$ non uniform black strings, namely long non uniform black string, with the extra direction length of the order of the $AdS$ curvature.Comment: Results extended. 14 pages, 5 figure