Description d'Acnodon senai n. sp. du Rio Jari (Brésil, Amapa) et redescription d'A. normani (Teleostei, serrasalmidae)

#Acnodon senai n. sp., décrite du rio Jari (Brésil, Amapa), est une espèce proche de #A. normani Gosline, 1951 décrite du rio Tocantins. Ces deux espèces ont un museau pointu, une bouche terminale et deux séries de dents du prémaxillaire nettement séparées. Ces caractères les différencient de #A. oligacanthus (Müller et Troschel, 1844), décrit du Surinam, chez qui le museau est arrondi, la bouche infère et les séries prémaxillaires accolées. Les branchiospines, rigides et bordées d'une membrane simple chez #A. normani, sont souples et bordées d'une membrane lobulée chez #A. senai$. (Résumé d'auteur

Le genre Serrasalmus (Pisces, Serrasalmidae) dans le bas Tocantins (Brésil, Parà), avec la description d'une espèce nouvelle, S. geryi, du bassin Araguaia-Tocantins

Les auteurs font une description complémentaire détaillée de 7 espèces du genre #Serrasalmus récoltées dans le cours inférieur du rio Tocantins, au cours de 3 années de collectes trimestrielles. Une espèce nouvelle, #S. geryi, est décrite du bas Tocantins et de l'Araguaia. Tous les spécimens de #S. calmoni ont été capturés dans la zone sous influence de la marée. Les autres espèces sont distribuées sur toute la portion de cours étudiée. Un seul spécimen de #S. denticulatus a été récolté et #S. striolatus, décrit du rio Parà, n'a pas été rencontré. La présence de #S. eigenmanni, espèce différente de #S. humeralis, et la présence de #S. gibbus, espèce différente de #S. rhombeus sont confirmées. Une clé d'identification est proposée et les relations entre les espèces sont discutées. #S. eigenmanni est placée, avec #S. calmoni dans le sous-genre #Pristobrycon. Les auteurs placent #S. geryi dans le sous-genre #Serrasalmus, proposant une extension de la définition de celui-ci. (Résumé d'auteur

Une nouvelle espèce de Bryconexodon (Pisces, Characidae) décrite du bassin du Trombetas (Para, Brésil)

Une nouvelle espèce du genre #Bryconexodon Géry (#Pisces, #Characidae) est décrite du cours supérieur du Rio Trombetas (Para, Brésil). #Bryconexodon n. sp. est très voisine de #B. juruenae Guéry, 1980 par la forme et la distribution des dents, mais présente moins d'écailles en ligne latérale (13-15 contre 17-19), moins de séries d'écailles au-dessus de la ligne latérale (8-9 contre 10-12) et autour du pédoncule caudale (16-18 contre 22). L'examen de contenus stomacaux révèle que #B. trombetasi n. sp. est lépidophage. (Résumé d'auteur

Une nouvelle espèce du genre Mylesinus (Pisces, Serrasalmidae), M. paraschomburgkii, décrite des bassins du Trombetas et du Uatuma (Brésil, Amazonie)

Une série de collectes, réalisées dans le bassin du Trombetas (Brésil, Para) et le bassin du Uatuma (Brésil, Amazonas), a permis de récolter de nombreux spécimens du genre #Mylesinus (Characiformes, #Serrasalmidae) de 13 à 365 mm de longueur standard. Après une mise au point de la littérature se rapportant au genre #Mylesinus, M. paraschomburgkii$ n.sp. est décrite. Au cours de la croissance, cette espèce présente de nombreuses modifications morphologiques et anatomiques. Certains caractères, comme la hauteur du corps ou la longueur de la tête, présentent de fortes allométries de croissance qui s'atténuent au-delà de 80 mm de longueur standard. Le nombre de dents à la mâchoire inférieure augmente régulièrement avec la taille des spécimens et, parallèlement, les dents, caniniformes et pointues chez les jeunes, deviennent plus larges et incisiformes. L'intestin présente une forte allométrie positive et son mode d'enroulement se modifie au cours de la croissance. Les auteurs relient ces modifications anatomiques à celle du régime alimentaire qui passe de carnivore à phytophage brouteur à partir de 50 mm de longueur standard. (Résumé d'auteur

FGF/heparin differentially regulates Schwann cell and olfactory ensheathing cell interactions with astrocytes: a role in astrocytosis

After injury, the CNS undergoes an astrocyte stress response characterized by reactive astrocytosis/proliferation, boundary formation, and increased glial fibrillary acidic protein (GFAP) and chondroitin sulfate proteoglycan (CSPG) expression. Previously, we showed that in vitro astrocytes exhibit this stress response when in contact with Schwann cells but not olfactory ensheathing cells (OECs). In this study, we confirm this finding in vivo by demonstrating that astrocytes mingle with OECs but not Schwann cells after injection into normal spinal cord. We show that Schwann cell-conditioned media (SCM) induces proliferation in monocultures of astrocytes and increases CSPG expression in a fibroblast growth factor receptor 1 (FGFR1)-independent manner. However, SCM added to OEC/astrocyte cocultures induces reactive astrocytosis and boundary formation, which, although sensitive to FGFR1 inhibition, was not induced by FGF2 alone. Addition of heparin to OEC/astrocyte cultures induces boundary formation, whereas heparinase or chlorate treatment of Schwann cell/astrocyte cultures reduces it, suggesting that heparan sulfate proteoglycans (HSPGs) are modulating this activity. In vivo, FGF2 and FGFR1 immunoreactivity was increased over grafted OECs and Schwann cells compared with the surrounding tissue, and HSPG immunoreactivity is increased over reactive astrocytes bordering the Schwann cell graft. These data suggest that components of the astrocyte stress response, including boundary formation, astrocyte hypertrophy, and GFAP expression, are mediated by an FGF family member, whereas proliferation and CSPG expression are not. Furthermore, after cell transplantation, HSPGs may be important for mediating the stress response in astrocytes via FGF2. Identification of factors secreted by Schwann cells that induce this negative response in astrocytes would further our ability to manipulate the inhibitory environment induced after injury to promote regeneration

GeoCLEF 2006: the CLEF 2006 Ccross-language geographic information retrieval track overview

After being a pilot track in 2005, GeoCLEF advanced to be a regular track within CLEF 2006. The purpose of GeoCLEF is to test and evaluate cross-language geographic information retrieval (GIR): retrieval for topics with a geographic specification. For GeoCLEF 2006, twenty-five search topics were defined by the organizing groups for searching English, German, Portuguese and Spanish document collections. Topics were translated into English, German, Portuguese, Spanish and Japanese. Several topics in 2006 were significantly more geographically challenging than in 2005. Seventeen groups submitted 149 runs (up from eleven groups and 117 runs in GeoCLEF 2005). The groups used a variety of approaches, including geographic bounding boxes, named entity extraction and external knowledge bases (geographic thesauri and ontologies and gazetteers)

Exact time-dependent correlation functions for the symmetric exclusion process with open boundary

As a simple model for single-file diffusion of hard core particles we investigate the one-dimensional symmetric exclusion process. We consider an open semi-infinite system where one end is coupled to an external reservoir of constant density $\rho^\ast$ and which initially is in an non-equilibrium state with bulk density $\rho_0$. We calculate the exact time-dependent two-point density correlation function $C_{k,l}(t)\equiv -$ and the mean and variance of the integrated average net flux of particles $N(t)-N(0)$ that have entered (or left) the system up to time $t$. We find that the boundary region of the semi-infinite relaxing system is in a state similar to the bulk state of a finite stationary system driven by a boundary gradient. The symmetric exclusion model provides a rare example where such behavior can be proved rigorously on the level of equal-time two-point correlation functions. Some implications for the relaxational dynamics of entangled polymers and for single-file diffusion in colloidal systems are discussed.Comment: 11 pages, uses REVTEX, 2 figures. Minor typos corrected and reference 17 adde

Quasivariational solutions for first order quasilinear equations with gradient constraint

We prove the existence of solutions for an evolution quasi-variational inequality with a first order quasilinear operator and a variable convex set, which is characterized by a constraint on the absolute value of the gradient that depends on the solution itself. The only required assumption on the nonlinearity of this constraint is its continuity and positivity. The method relies on an appropriate parabolic regularization and suitable {\em a priori} estimates. We obtain also the existence of stationary solutions, by studying the asymptotic behaviour in time. In the variational case, corresponding to a constraint independent of the solution, we also give uniqueness results

Inventário De Moluscos Do Estuário Do Rio Paraíba No Nordeste Do Brasil

Coastal ecosystems of northeastern Brazil have important biodiversity with regard to marine mollusks, which are insufficiently studied. Here we provide an inventory of mollusks from two sites in the estuary of the Paraíba River. Mollusks were collected in 2014 and 2016 on the coast and sandbanks located on the properties of Treze de Maio and Costinha de Santo Antônio. The malacofaunal survey identified 12 families, 20 genera and 21 species of bivalves, 17 families, 19 genera and 20 species of gastropods and one species of cephalopod. Bivalves of the family Veneridae Rafinesque, 1815 were the most representative, with a total of five species. Gastropods of the family Littorinidae Children, 1834 had the greatest species richness. The most abundant species were: Neritina virginea (Linnaeus, 1758), Brachidontes exustus (Linnaeus, 1758), Crassostrea brasiliana (Lamarck, 1819), Cerithium atratum (Born, 1778), Anomalocardia brasiliana (Gmelin, 1791), Parvanachis obesa (C. B. Adams, 1845), Phrontis polygonata (Lamarck, 1822), Littoraria angulifera (Lamarck, 1822), L. flava (King, 1832), Tagelus plebeius (Lightfoot, 1786), Echinolittorina lineolata (d’Orbigny, 1840) and Iphigenia brasiliensis (Lamarck, 1818). The results show that the study area has considerable species richness of Mollusca, requiring environmental monitoring in the region mainly due to the economic importance of some species to the local population. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17

Laser cooling of a trapped two-component Fermi gas

The collective Raman cooling of a trapped two-component Fermi gas is analyzed. We develop the quantum master equation that describes the collisions and the laser cooling, in the festina lente regime, where the heating due to photon reabsorption can be neglected. The numerical results based on Monte Carlo simulations show, that three-dimensional temperatures of the order of 0.008 T_F can be achieved. We analyze the heating related to the background losses, and conclude that our laser-cooling scheme can maintain the temperature of the gas without significant additional losses. Finally we derive an analytic expression for the temperature of a trapped Fermi gas heated by background collisions, that agrees very well with the data obtained from the numerical simulation.Comment: 5 pages, 3 figure