Serological evidence for Japanese encephalitis and West Nile virus infections in domestic birds in Cambodia

Mosquito-borne flaviviruses with an enzootic transmission cycle like Japanese encephalitis virus (JEV) and West Nile virus (WNV) are a major public health concern. The circulation of JEV in Southeast Asia is well-documented, and the important role of pigs as amplification hosts for the virus is long known. The influence of other domestic animals especially poultry that lives in high abundance and close proximity to humans is not intensively analyzed. Another understudied field in Asia is the presence of the closely related WNV. Such analyses are difficult to perform due to the intense antigenic cross-reactivity between these viruses and the lack of suitable standardized serological assays. The main objective of this study was to assess the prevalence of JEV and WNV flaviviruses in domestic birds, detailed in chickens and ducks, in three different Cambodian provinces. We determined the flavivirus seroprevalence using an hemagglutination inhibition assay (HIA). Additionally, we investigated in positive samples the presence of JEV and WNV neutralizing antibodies (nAb) using foci reduction neutralization test (FRNT). We found 29% (180/620) of the investigated birds positive for flavivirus antibodies with an age-depended increase of the seroprevalence (OR = 1.04) and a higher prevalence in ducks compared to chicken (OR = 3.01). Within the flavivirus-positive birds, we found 43% (28/65) with nAb against JEV. We also observed the expected cross-reactivity between JEV and WNV, by identifying 18.5% double-positive birds that had higher titers of nAb than single-positive birds. Additionally, seven domestic birds (10.7%) showed only nAb against WNV and no nAb against JEV. Our study provides evidence for an intense JEV circulation in domestic birds in Cambodia, and the first serological evidence for WNV presence in Southeast Asia since decades. These findings mark the need for a re-definition of areas at risk for JEV and WNV transmission, and the need for further and intensified surveillance of mosquito-transmitted diseases in domestic animals

On reducing the complexity of matrix clocks

Matrix clocks are a generalization of the notion of vector clocks that allows the local representation of causal precedence to reach into an asynchronous distributed computation's past with depth $x$, where $x\ge 1$ is an integer. Maintaining matrix clocks correctly in a system of $n$ nodes requires that everymessage be accompanied by $O(n^x)$ numbers, which reflects an exponential dependency of the complexity of matrix clocks upon the desired depth $x$. We introduce a novel type of matrix clock, one that requires only $nx$ numbers to be attached to each message while maintaining what for many applications may be the most significant portion of the information that the original matrix clock carries. In order to illustrate the new clock's applicability, we demonstrate its use in the monitoring of certain resource-sharing computations

Effet de la température seuil de développement sur la répartition géographique d'une variété

A La Réunion, de nouvelles variétés sélectionnées pour des environnements contraints, notamment vis-à-vis de températures basses font la preuve de leur meilleure adaptabilité en produisant plus de biomasse dans les Hauts de l'ile. La dynamique de levée de populations homogènes de boutures d'un seul bourgeon a été étudiée et caractérisée en chambres climatiques à différentes températures constantes, pour trois variétés contrastées. La levée des boutures en fonction du temps est plus rapide et plus complète pour la variété R583, qui est connue pour être mieux adaptée aux basses températures que pour R570 et R577. Se basant sur l'hypothèse d'une température seuil de fonctionnement plus basse, une simulation des durées de débourrement-levée est réalisée par zone, sur la côte Ouest de La Réunion à partir de données climatiques des 10 dernières années. Un écart de 2 degrés sur le seuil montre l'importance relative de ce paramètre sur la date de levée, ce qui laisse supposer une faculté de la plante à s'implanter plus rapidement. Un parallèle est fait entre les limites géographiques obtenues, où l'implantation à dire d'expert est possible au vu du temps nécessaire en jour pour la levée et celles qu'illustrent les zones effectives récentes de plantations de la variété R583. La bonne implantation d'une variété, sans garantir une meilleure production finale en biomasse et en sucre, représente un atout indéniable dans l'implantation de la culture, notamment pour la compétition vis-à-vis de la flore adventice. L'outil de cartographie, associé utilisant les nombreuses données météorologiques disponibles, a permis d'illustrer l'effet de 2 valeurs de températures seuils sur la durée nécessaire à la levée. (Résumé d'auteur

El Jurásico en la región de Obon (Teruel)

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Bounded version vectors

Version vectors play a central role in update tracking under optimistic distributed systems, allowing the detection of obsolete or inconsistent versions of replicated data. Version vectors do not have a bounded representation; they are based on integer counters that grow indefinitely as updates occur. Existing approaches to this problem are scarce; the mechanisms proposed are either unbounded or operate only under specific settings. This paper examines version vectors as a mechanism for data causality tracking and clarifies their role with respect to vector clocks. Then, it introduces bounded stamps and proves them to be a correct alternative to integer counters in version vectors. The resulting mechanism, bounded version vectors, represents the first bounded solution to data causality tracking between replicas subject to local updates and pairwise symmetrical synchronization.FCT project POSI/ICHS/44304/2002, FCT under grant BSAB/390/2003

Biostratigraphic sequence of Portuguese West-basin. Differentiation during the Lias and Dogger.

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu