Recherches sur les risques pouvant resulter de la pollution chimique des eaux d'alimentation—II. Etudes comparatives de la toxicite a long terme et de la cytotoxicite des micropolluants organiques extraits des eaux utilisees pour la preparation des eaux d'alimentation

Micropollutants extracted by chloroform from raw river waters used for preparation of drinking waters have been divided into two categories pending the degree of cytotoxicity shown by another team of research using a given cellular system: fractions with high cytotoxicity and fractions with low cytotoxicity.In parallel groups of 50 rats and 60 mice, half male and female, were fed, from weaning, diets containing those fractions.Comparison of the results showed a correlation between the two types of results, only in the case of some biochemical parameters.In regard to the long term effects (lesions of the liver, increase in the incidence of malignant tumors in treated animals), no correlation could be found.

Résumé

Des micropolluants organiques préparés par extraction chloroformique d'eaux brutes ont été répartis en 2 catégories, en fonction des résultats obtenus dans les investigations d'une autre équipe de chercheurs sur un systéme cellulaire: fractions à cytotoxicité forte et fractions à cytotocixité faible.Parallélement, des groupes de 50 rats et de 60 souris, par moitié mâles et femelles, ont reçu dans leur régime, à partir du sevrage et pendant pratiquement toute leur vie, les deux catégories de micropolluants.La comparaison des résultats obtenus dans les 2 types d'investigations nà révélé de corrélation que dans le cas de certains paramétres biochimiques et encore seulement dans une certaine mesure. En ce qui concerne les effets à long terme observés chez les lots traités des 2 espéces animales soumises aux épreuves (nettes altérations hépatique, augmentation de l'incidence des tumeurs malignes), aucune corrélation n'a pu être établie entre les critéres toxicologiques retenus et le degré de cytotoxicité des micropolluants sur le système cellulaire utilisé.     

Configuration of ACK Trees for Multicast Transport Protocols

For scalable multicast transport, one of the promising approaches is to employ a control tree known as acknowledgement (ACK) tree which can be used to convey information on reliability and session status from receivers to a root sender. The existing tree configuration has focused on a ‘bottom‐up’ scheme in which ACK trees grow from leaf receivers toward a root sender. This paper proposes an alternative ‘top‐down’ configuration where an ACK tree begins at the root sender and gradually expands by including non‐tree nodes into the tree in a stepwise manner. The proposed scheme is simple and practical to implement along with multicast transport protocols. It is also employed as a tree configuration in the Enhanced Communications Transport Protocol, which has been standardized in the ITU‐T and ISO/IEC JTC1. From experimental simulations, we see that the top‐down scheme provides advantages over the existing bottom‐up one in terms of the number of control messages required for tree configuration and the number of tree levels.     

Probe test yield optimization based on canonical correlation analysis between process control monitoring variables and probe bin variables

Process control monitoring (PCM) data provide information that is used to track abnormal processes and estimate various probe bin yields. However, multi-dimensional information has not yet been fully utilized from both PCM data and probe bins. In this paper, we proposed a canonical correlation analysis in order to investigate the relationship between multiple PCM variables and various probe bin variables. Polynomial regression was also employed as a methodology for maximizing the performance yield based on the results of the canonical correlation analysis. Two conclusions were drawn from the results of this research. First, the PCM variables that affected the probe bins were contact resistance, sheet resistance, and Isat_P4H as well as threshold voltage (Vt) during the process tuning step. Second, the typical values of Vtl_P4H and Isat_P4H should be changed in order to maximize the performance yield. The proposed method can be used for yield improvement and as a problem-solving approach for optimizing the IC process.     

A router-assisted session tree configuration mechanism for reliablemulticast

A session tree based mechanism provides an efficient method to avoid well-known feedback implosion. However, it is not easy to configure an efficient session tree for IP multicast because it does not provide any explicit membership and routing topology information to the upper layer protocol. Incongruity between a session tree built on the transport layer and the corresponding routing tree on the network layer would incur large cost to handle control messages. This problem can be solved if a router that knows the information of routing topology can support the configuration of a session tree. Thus this letter proposed a router-assistant mechanism which minimizes the change of router functions and allows the routers to assist in providing a reliable multicast transport service