Size at maturity, reproduction and recruitment in an amphidromous shrimp Caridina serratirostris De Man, 1892 in Reunion Island (Decapoda: Atyidae)

Abstract: Fisheries of small freshwater shrimps are relatively important in certain countries. In Reunion Island, South-West Indian Ocean, a traditional recreational fishery particularly targets Atyoidaserrata (Spence Bate, 1888), which is endemic of the south-west Indian Ocean. However, a species with an Indo-Pacific distribution Caridinaserratirostris (De Man, 1892), which is a threatened species at the island scale, can occur as a by-catch. Knowledge of the biology and particularly the reproduction is essential to preserve this species. A population of C. serratirostris was sampled by electrofishing on five occasions from August 2015 until May 2016 on the Marsouins River. The size at maturity of females was estimated at 13.5 mm but the reproductive population comprised less than 6% of the total catch. Reproduction occurred throughout the survey but an increase was observed during the hot and wet season. The main factor that influenced the onset of the reproduction was the temperature. The reproductive season was followed by a recruitment peak. Firstly, this study suggested to acquire knowledge of the stock distribution in order to conserve them. Secondly, it recommended a global crustacean fishing closure during the reproductive season.Résumé : La pêcherie de petites crevettes est une activité relativement importante dans certains pays. A l’île de La Réunion, dans le Sud-Ouest de l'océan Indien, une pêche traditionnelle cible Atyoidaserrata (Spence Bate, 1888) endémique du Sud-Ouest de l’Océan Indien. Caridinaserratirostris (De Man, 1892), une espèce à répartition Indo-Pacifique, est localement menacée. Elle peut être capturée comme prise accessoire. La connaissance de la biologie et plus précisément la reproduction est indispensable pour la préservation de cette espèce. Une population de C. serratirostris a été échantillonnée par pêche électrique à cinq reprises entre août 2015 et mai 2016 sur la Rivière des Marsouins. La taille à maturité des femelles a été estimée à 13,5 mm. La population d’individus matures représentait moins de 6% de l’ensemble des captures. Même si la reproduction a été observée tout au long du suivi, elle a considérablement augmenté au cours de la saison chaude et humide. Le principal facteur qui a influencé le déclenchement de la saison de reproduction était la température. Après cette saison de reproduction, un pic de l'effectif de jeunes individus a été enregistré. Cette étude recommande l’acquisition de données sur la répartition des populations afin de les conserver. Elle conseille également une fermeture de la pêche durant la période de reproduction

Lie group stability of finite difference schemes

Differential equations arising in fluid mechanics are usually derived from the intrinsic properties of mechanical systems, in the form of conservation laws, and bear symmetries, which are not generally preserved by a finite difference approximation, and leading to inaccurate numerical results. This paper proposes a method that enables us to build a scheme that preserves some of those symmetries.Comment: 10 page

Note sur la fécondité de Caridina longirostris H. Milne Edwards, 1837 et de son évolution au cours de l’incubation sur une petite rivière du Nord de Mayotte, archipel des Comores, Sud-Ouest de l’océan Indien (Decapoda : Atyidae)

Abstract: The complex life cycle of amphidromous species is shared between the ocean and rivers. Management actions can easily take place only in rivers. The knowledge of the reproduction biology of a shrimp such as Caridina longirostris H. Milne Edwards, 1837 is essential in order to protect and preserve populations in Mayotte Island. Fecundity and brood evolution were studied on a small stream in the North of the main Island of Mayotte. Ovigerous females were sampled by electrofishing and measured. Eggs were counted and characterized by their stage of development. Fecundity fluctuates between 435 and 2,195 eggs for individuals from 22.0 to 32.5 mm. It is positively correlated with the female size. The decrease of 19.4% of fecundity during the incubation is only noticed in shrimps under 28 mm. This result would be explained by the fact that bigger females are not enough numerous in the sample. Furthermore, the lost in smallest females would partially be due to the egg volume increase of 49.8%. Résumé : Le cycle de vie amphidrome, partagé entre l’océan et les rivières, est complexe. Les mesures de gestion des peuplements des espèces qui possèdent ce type de cycle de vie ne peuvent facilement être mises en place qu’en rivière. La connaissance de la biologie de la reproduction des crevettes comme Caridina longirostris H. Milne Edwards, 1837 est primordiale afin de protéger et de conserver les populations de l'île de Mayotte. C’est dans ce contexte que la fécondité et l’évolution de la ponte au cours de l’incubation ont fait l’objet d’une première investigation sur une petite rivière du Nord de l’île de Grande Terre de Mayotte. Des femelles ovigères recueillies par pêche électrique ont été mesurées. Leur ponte a été dénombrée et caractérisée par rapport à leur développement. La fécondité de 435 à 2 195 œufs pour des individus de 22,0 à 32,5 mm est positivement corrélée avec la taille des femelles. La diminution de 19,4% de la fécondité au cours de l’incubation est observée uniquement chez les femelles de moins de 28 mm. Cette observation résulterait d’une sous représentativité des gros individus. De plus la perte chez les petites femelles serait en partie due à l’augmentation de 49,8% du volume des œufs

FAIL-MPI: How fault-tolerant is fault-tolerant MPI ?

One of the topics of paramount importance in the development of Cluster and Grid middleware is the impact of faults since their occurrence probability in a Grid infrastructure and in large-scale distributed system is actually very high. MPI (Message Passing Interface) is a popular abstraction for programming distributed computation applications. FAIL is an abstract language for fault occurrence description capable of expressing complex and realistic fault scenarios. In this paper, we investigate the possibility of using FAIL to inject faults in a fault-tolerant MPI implementation. Our middleware, FAIL-MPI, is used to carry quantitative and qualitative faults and stress testing

Combined Thoracic Ultrasound Assessment during a Successful Weaning Trial Predicts Postextubation Distress

International audienceBackground: Recent studies suggest that isolated sonographic assessment of the respiratory, cardiac, or neuromuscular functions in mechanically ventilated patients may assist in identifying patients at risk of postextubation distress. The aim of the present study was to prospectively investigate the value of an integrated thoracic ultrasound evaluation, encompassing bedside respiratory, cardiac, and diaphragm sonographic data in predicting postextubation distress.Methods: Longitudinal ultrasound data from 136 patients who were extubated after passing a trial of pressure support ventilation were measured immediately after the start and at the end of this trial. In case of postextubation distress (31 of 136 patients), an additional combined ultrasound assessment was performed while the patient was still in acute respiratory failure. We applied machine-learning methods to improve the accuracy of the related predictive assessments.Results: Overall, integrated thoracic ultrasound models accurately predict postextubation distress when applied to thoracic ultrasound data immediately recorded before the start and at the end of the trial of pressure support ventilation (learning sample area under the curve: start, 0.921; end, 0.951; test sample area under the curve: start, 0.972; end, 0.920). Among integrated thoracic ultrasound data, the recognition of lung interstitial edema and the increased telediastolic left ventricular pressure were the most relevant predictive factors. In addition, the use of thoracic ultrasound appeared to be highly accurate in identifying the causes of postextubation distress.Conclusions: The decision to attempt extubation could be significantly assisted by an integrative, dynamic, and fully bedside ultrasonographic assessment of cardiac, lung, and diaphragm functio

Unconventional Repertoire Profile Is Imprinted during Acute Chikungunya Infection for Natural Killer Cells Polarization toward Cytotoxicity

Chikungunya virus (CHIKV) is a worldwide emerging pathogen. In humans it causes a syndrome characterized by high fever, polyarthritis, and in some cases lethal encephalitis. Growing evidence indicates that the innate immune response plays a role in controlling CHIKV infection. We show here that CHIKV induces major but transient modifications in NK-cell phenotype and function soon after the onset of acute infection. We report a transient clonal expansion of NK cells that coexpress CD94/NKG2C and inhibitory receptors for HLA-C1 alleles and are correlated with the viral load. Functional tests reveal cytolytic capacity driven by NK cells in the absence of exogenous signals and severely impaired IFN-γ production. Collectively these data provide insight into the role of this unique subset of NK cells in controlling CHIKV infection by subset-specific expansion in response to acute infection, followed by a contraction phase after viral clearance

Chikungunya Disease: Infection-Associated Markers from the Acute to the Chronic Phase of Arbovirus-Induced Arthralgia

At the end of 2005, an outbreak of fever associated with joint pain occurred in La Réunion. The causal agent, chikungunya virus (CHIKV), has been known for 50 years and could thus be readily identified. This arbovirus is present worldwide, particularly in India, but also in Europe, with new variants returning to Africa. In humans, it causes a disease characterized by a typical acute infection, sometimes followed by persistent arthralgia and myalgia lasting months or years. Investigations in the La Réunion cohort and studies in a macaque model of chikungunya implicated monocytes-macrophages in viral persistence. In this Review, we consider the relationship between CHIKV and the immune response and discuss predictive factors for chronic arthralgia and myalgia by providing an overview of current knowledge on chikungunya pathogenesis. Comparisons of data from animal models of the acute and chronic phases of infection, and data from clinical series, provide information about the mechanisms of CHIKV infection–associated inflammation, viral persistence in monocytes-macrophages, and their link to chronic signs

Calcul quantique de l’anisotropie magnétique de bandes graphitiques

L’application de la méthode de LONDON au calcul de l'ani- sotropie magnétique de bandes graphitiques planes de largeur limitée (à 0 °K) conduit à des formules analytiques générales grâce à un choix convenable des conditions aux limites (lorsque l’on suppose que le champ magnétique tend vers 0).Les résultats permettent d’interpréter la variation importante de susceptibilité observée expérimentalement en fonction de la largeur des crislallites graphitiques formant les carbones prégraphitiques, mais conduisent à une anisotropic infinie pour un plan graphitique illimité.On donne également quelques caractéristiques de ces bandes en l’absence de champ magnétique (largeur de la bande interdite, énergie de résonance, indice de liaison mobile)

A representation of the collisional ice break-up process in the two-moment microphysics scheme LIMA v1.0 of Meso-NH

International audienc