On Prophoca and Leptophoca (Pinnipedia, Phocidae) from the Miocene of the North Atlantic realm : redescription, phylogenetic affinities and paleobiogeographic implications

Background: Prophoca and Leptophoca represent the oldest known genera of phocine seals, dating from the latest early to middle Miocene. Originally, Prophoca rousseaui and Prophoca proxima were described based on fragmentary remains from the Miocene of Belgium. However, several researchers contested the union of Prophoca rousseaui and Prophoca proxima into one genus, without providing evidence. The stratigraphic context of Prophoca remained poorly constrained due to the lack of precise data associated with the original specimens collected in the area of Antwerp (north of Belgium). Methods: Prophoca and Leptophoca are redescribed and their phylogenetic position among Phocidae is reassessed using PAUP. Dinoflagellate biostratigraphy has been carried out on sediment samples associated with specimens from Prophoca and Leptophoca to elucidate their approximate ages. Results: Whereas the species Prophoca rousseaui is redescribed, Prophoca proxima is considered synonymous to Leptophoca lenis, with the proposal of a new combination Leptophoca proxima (Van Beneden, 1877). Sediment samples from specimens of both taxa have been dated to the late Langhian-early Serravallian (middle Miocene). Following a reinvestigation of Leptophoca amphiatlantica, characters from the original diagnosis are questioned and the specimens of Leptophoca amphiatlantica are considered Leptophoca cf. L. proxima. In a phylogenetic analysis, Prophoca rousseaui and Leptophoca proxima constitute early branching stem-phocines. Discussion: Leptophoca proxima from the North Sea Basin is younger than the oldest known find of Leptophoca proxima from North America, which does not contradict the hypothesis that Phocinae originated along the east coast of North America during the late early Miocene, followed by dispersal to Europe shortly after. Morphological features of the appendicular skeleton indicate that Prophoca rousseaui and Leptophoca proxima have archaic locomotory modes, retaining a more prominent use of the fore flipper for aquatic propulsion than extant Phocidae

A critical revision of the fossil record, stratigraphy and diversity of the Neogene seal genus Monotherium (Carnivora, Phocidae)

Historically, Monotherium had been one of the few genera of extinct Phocidae (true seals) that served as a wastebin taxon. Consequently, it did neither aid in understanding phylogenetic relationships of extinct Phocidae, nor in understanding seal diversity in deep time. This urged the reassessment of the genus. Before our review, Monotherium included five different species: Monotherium aberratum, Monotherium affine, and Monotherium delognii from Belgium; Monotherium gaudini from Italy; and Monotherium? wymani from the east coast USA. In this work we redescribe the fossil record of the genus, retaining the type species M. delognii. Monotherium aberratum and M. affine are reassigned to the new phocine genus Frisiphoca. Monotherium gaudini is renamed and considered a stem-monachine (Noriphoca gaudini). The holotype of the monachine M.? wymani requires further study pending the discovery of new fossil material that could be attributed to the same taxon. Reinvestigating the stratigraphic context reveals that N. gaudini most likely represents one of the two oldest named phocid seals, or even the oldest, dated to the late Oligocene-earliest Miocene. Our results allow questioning the widespread idea that Phocidae originated in the western Atlantic and better appreciate their palaeobiogeography during the late Oligocene-Miocene interval in the North Atlantic realm

Suites maximales vertes des carquois acycliques à trois sommets

Les algèbres amassées sont très intéressantes, entre autre du point de vue de la théorie des représentations. Leurs côtés combinatoires sont immenses et on a probablement seulement effleuré le sujet. Dans ce mémoire, nous allons amorcer l'étude d'une propriété combinatoire pour un cas particulier d'algèbres amassées. Nous espérons que notre travail jettera les bases pour l'étude du cas général. Notre but sera de prouver le théorème suivant: Théorème 0.1. Tous les carquois acycliques et connexes à trois sommets ant un nombre fini de suites maximales vertes. Nous allons done expliquer tout ce qu'il y a à savoir sur les carquois et par la suite, présenter la preuve de ce théorème. Comme supplément, nous donnerons en plus la liste complète de toutes les suites maximales vertes possibles pour ces carquois

Strong fluid–solid interactions with segregated CFD solvers

Purpose: A fluid-structure coupling partitioned scheme involving rigid bodies supported by spring-damper systems is presented. This scheme can be used with already existing fluid flow solvers without the need to modify them. Design/methodology/approach: The scheme is based on a modified Broyden method. It solves the equations of solid body motion in which the external forces coming from the flow are provided by a segregated flow solver used as a black box. The whole scheme is implicit. Findings: The proposed partitioned method is stable even in the ultimate case of very strong fluid-solid interactions involving a massless cylinder oscillating with no structural damping. The overhead associated with the coupling scheme represents an execution time increase by a factor of about 2 to 5, depending on the context. The scheme also has the advantage of being able to incorporate turbulence modeling directly through the flow solver. It has been tested successfully with URANS simulations without wall law, thus involving thin high aspect-ratio cells near the wall. Originality/value: Such problems are known to be very difficult to solve and previous studies usually rely on monolithic approaches. To the authors’ knowledge, this is the first time a partitioned scheme is used to solve fluid-solid interactions involving massless component

A new delphinid from the lower Pliocene of the North Sea and the early radiations of true dolphins

Abstract. With a remarkable exception for the Mediterranean, the worldwide Pliocene record of true dolphins (Cetacea, Odontoceti, Delphinidae) remains scarce, in stark contrast with the large number of extant species testifying to the evolutionary success of this family. Based on a fragmentary skull discovered in lower Pliocene deposits (Zanclean, 5 to 4.4 Ma) of the Kattendijk Formation in the Antwerp harbour (Belgium, southern margin of the North Sea basin), we describe here a new delphinid species, Pliodelphis doelensis gen. et sp. nov. This small dolphin with cranial dimensions in the range of the short-beaked common dolphin Delphinus delphis can be distinguished from other extinct and extant delphinids by a combination of cranial features including the maxilla being significantly narrower than the premaxilla at a short distance anterior to the antorbital notch in dorsal view, the maximum opening of the mesorostral groove being located at the level of the antorbital notches, a transversely wide and anteroposteriorly long dorsal exposure of the presphenoid anterior to the bony nares, and all dorsal infraorbital foramina being located posterior to the premaxillary foramina. P. doelensis constitutes the first member of the family described from the early Pliocene of the North Sea basin and, for the whole North Atlantic realm, only the third outside the Mediterranean. This new record contributes thus to our understanding of the poorly known Pliocene radiation(s) of true dolphins

On the Rate of Almost Everywhere Convergence of Certain Classical Integral Means

AbstractThe main purpose of this article is to establish nearly optimal results concerning the rate of almost everywhere convergence of the Gauss–Weierstrass, Abel–Poisson, and Bochner–Riesz means of the one-dimensional Fourier integral. A typical result for these means is the following: If the function f belongs to the Besov spaceBsp,p, 1<p<∞, 0<s<1, thenTmtf (x)−f(x)=ox(ts) a.e. ast→0+

A new Beneziphius beaked whale from the ocean floor off Galicia, Spain and biostratigraphic reassessment of the type species

Although the fossil record of beaked whales (Cetacea, Odontoceti, Ziphiidae) is continuously improving, the geological age of new taxa is often poorly constrained. Based on a partial cranium from deep seafloor deposits off Galicia, Spain, we describe a new species of the stem beaked whale genus Beneziphius, B. cetariensis sp. nov. The latter differs from the type species B. brevirostris in the larger size, the rostrum being proportionally longer, the premaxillae being longer than the maxillae at the apex of the rostrum, the left premaxillary sac fossa being transversely concave, and the ascending process of the premaxilla reaching the vertical. Considering that the stratigraphic context of deep-sea deposits off the Iberian Peninsula is not precisely known, we provisionally propose an extended, middle Miocene to early Pliocene interval for the geological age of B. cetariensis. Nonetheless, the palynological analysis of sediment sampled from cavities in the cranium of the holotype of B. brevirostris, discovered during the second part of the nineteenth century in inland deposits of Antwerp (north of Belgium), yield an early to mid-Serravallian age (13.2-12.8 Ma, late middle Miocene). B. brevirostris is thus the oldest described species of the "Messapicetus clade", a large clade of stem ziphiids in which most species are dated from the late Miocene. The description of the Galician species B. cetariensis broadens the biogeographic distribution of Beneziphius and confirms the strong ziphiid faunal affinities between the eastern coast of the North Atlantic and the southern margin of the North Sea Basin

A new archaic homodont toothed cetacean (Mammalia, Cetacea, Odontoceti) from the early Miocene of Peru

Apart from a few exceptions, extant odontocetes (toothed cetaceans) exhibit a roughly homodont dentition. The transition from basilosaurid-like double-rooted cheek teeth with accessory denticles to single-rooted conical teeth occurred during the late Oligocene-early Miocene. At that time, several clades of now extinct, homodont and predominantly long-snouted odontocetes appeared in the fossil record. Among them, members of the genera Argyrocetus Lydekker, 1893 and Macrodelphinus Wilson, 1935, from the early Miocene of the Northeast Pacific and Argentina, were tentatively attributed to the family Eurhinodelphinidae. However, due to the fragmentary state of the specimens, unambiguous apomorphies of the family could not be detected. Based on two well-preserved skulls with associated mandibular elements, discovered in early Miocene layers of the Chilcatay Formation (Pisco Basin, Peru), we report on a new genus and species of long-snouted homodont odontocete, Chilcacetus cavirhinus n. gen., n. sp. Characterized by, among others, the presence of alveoli on the anterior premaxillary portion of the rostrum, the lack of a lateral groove on the rostrum, anterodorsally elevated nasals, a possibly autapomorphic cavity between nasals and mesethmoid in the posterior wall of the bony nares, a high temporal fossa, and the absence of ankylosis along the mandibular symphysis, C. cavirhinus n. gen., n. sp. does not fit in any of the known odontocete families, but shares several morphological features with Argyrocetus spp. and Macrodelphinus. Our phylogenetic analysis, based on 77 characters for 35 odontocete taxa, suggests the existence of an early Miocene Eastern Pacific long-snouted homodont odontocete clade (with an hypothetical South Atlantic member, the poorly known Argyrocetus patagonicus Lydekker, 1893), distinct from the only superficially similar eoplatanistids and eurhinodelphinids. Furthermore, our consensus tree indicates an early branching of this new clade compared to other homodont odontocete lineages. Unfortunately, the results of the cladistic analysis presented here are not well supported; a reappraisal of Argyrocetus and Macrodelphinus is needed to more clearly define the new clade and bolster its phylogentic position

Relationships between the physicochemical properties of an amphiphilic triblock copolymers/DNA complexes and their intramuscular transfection efficiency

Poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) triblock copolymer (PEO-PPO-PEO) based plasmid delivery systems are increasingly drawing attention in the field of nonviral gene transfer because of their proven in vivo transfection capability. They result from the simple association of DNA molecules with uncharged polymers. We examined the physicochemical properties of PEO-PPO-PEO/DNA mixtures, in which the PEO-PPO-PEO is Lutrol® (PEO(75)-PPO(30)-PEO(75)), formulated under various conditions. We found that interactions between PEO-PPO-PEO and DNA are mediated by the central hydrophobic block within the block copolymer. Dynamic light scattering and cryo-electron microscopy showed that the mean diameter of transfecting particles as well as their stability depended on the PEO-PPO-PEO/DNA ratio and on the ionic composition of the formulating medium. The most active formulation promoting a good tissue-distribution and an optimal transfection was characterized by a reduced electrophoretic mobility, a mean hydrodynamic diameter of ∼250–300 nm and by a conserved B-DNA form as shown by circular dichroism studies. Our study also revealed that the stability of these formulations strongly depended on a concentration balance between the DNA and the PEO-PPO-PEO, over which the DNA conformation was modified, micron-sized particles were generated, and the transgene expression was declined. We showed that the physicochemical properties of PEO-PPO-PEO/DNA formulations directly impact the level of gene expression in transfected muscles

De la désindustrialisation à la re-industrialisation.

La zone d’activités de Peynier-Rousset s’affirme comme un pôle industriel prospère tourné vers la microélectronique et les nouvelles technologies. Créée en 1961, elle a pris un virage décisif avec l’arrivée de l’industrie des semi-conducteurs au début des années 1980. Son exemple est d’autant plus intéressant que cette zone se situe dans un espace économique – le bassin de Gardanne – marqué par la désindustrialisation et la disparition des activités minières. À partir de son étude, il nous est ainsi permis de nous interroger sur le processus de reconversion à l’œuvre au sein des territoires industriels en prise avec la désagrégation de leur tissu traditionnel.The industrial area of Peynier-Rousset appears as a prosperous industrial Center turned to the microelectronics and new technologies. Founded in 1961, it took a decisive turn with the arrival of the semiconductor industry in the early 1980s. This example is particularly interesting because this area is located in the coalfield of Gardanne which is marked by deindustrialization and loss of mining activities. From this study, it is thus possible to wonder about the conversion process at work in the industrial areas engaged with the disintegration of their traditional economic structures