The changing global distribution and prevalence of canine transmissible venereal tumour.

BACKGROUND: The canine transmissible venereal tumour (CTVT) is a contagious cancer that is naturally transmitted between dogs by the allogeneic transfer of living cancer cells during coitus. CTVT first arose several thousand years ago and has been reported in dog populations worldwide; however, its precise distribution patterns and prevalence remain unclear. RESULTS: We analysed historical literature and obtained CTVT prevalence information from 645 veterinarians and animal health workers in 109 countries in order to estimate CTVT's former and current global distribution and prevalence. This analysis confirmed that CTVT is endemic in at least 90 countries worldwide across all inhabited continents. CTVT is estimated to be present at a prevalence of one percent or more in dogs in at least 13 countries in South and Central America as well as in at least 11 countries in Africa and 8 countries in Asia. In the United States and Australia, CTVT was reported to be endemic only in remote indigenous communities. Comparison of current and historical reports of CTVT indicated that its prevalence has declined in Northern Europe, possibly due to changes in dog control laws during the nineteenth and twentieth centuries. Analysis of factors influencing CTVT prevalence showed that presence of free-roaming dogs was associated with increased CTVT prevalence, while dog spaying and neutering were associated with reduced CTVT prevalence. Our analysis indicated no gender bias for CTVT and we found no evidence that animals with CTVT frequently harbour concurrent infectious diseases. Vincristine was widely reported to be the most effective therapy for CTVT. CONCLUSIONS: Our results provide a survey of the current global distribution of CTVT, confirming that CTVT is endemic in at least 90 countries worldwide. Additionally, our analysis highlights factors that continue to modify CTVT's prevalence around the world and implicates free-roaming dogs as a reservoir for the disease. Our analysis also documents the disappearance of the disease from the United Kingdom during the twentieth century, which appears to have been an unintentional result of the introduction of dog control policies.This is the author's accepted manuscript. The final version of this article has been published by BioMed Central: http://www.biomedcentral.com/1746-6148/10/168

An Environment-Sensitive Synthetic Microbial Ecosystem

Microbial ecosystems have been widely used in industrial production, but the inter-relationships of organisms within them haven't been completely clarified due to complex composition and structure of natural microbial ecosystems. So it is challenging for ecologists to get deep insights on how ecosystems function and interplay with surrounding environments. But the recent progresses in synthetic biology show that construction of artificial ecosystems where relationships of species are comparatively clear could help us further uncover the meadow of those tiny societies. By using two quorum-sensing signal transduction circuits, this research designed, simulated and constructed a synthetic ecosystem where various population dynamics formed by changing environmental factors. Coherent experimental data and mathematical simulation in our study show that different antibiotics levels and initial cell densities can result in correlated population dynamics such as extinction, obligatory mutualism, facultative mutualism and commensalism. This synthetic ecosystem provides valuable information for addressing questions in ecology and may act as a chassis for construction of more complex microbial ecosystems

Handicap et citoyenneté une approche interdisciplinaire

De manière générale, le concept de citoyenneté a considérablement évolué. En ce qui concerne le handicap, le passage d’un modèle médical à un modèle social et ensuite à un point de vue psychosocial et pluridisciplinaire a transformé les modalités d’intervention. Les personnes en situation de handicap de bénéficiaires-usagers sont devenues des bénéficiaires-experts, socialement incluses plutôt qu’insérées. Une justice sociale réellement inclusive ne peut s’instaurer qu’à travers des processus d’apprentissages de l’ensemble des personnes concernées, usagers, professionnels, chercheurs, experts, politiques

Development and performance of a high pressure hydrogen time projection chamber

We describe a high pressure hydrogen gas time projection chamber (TPC) which is presently operating at Fermilab both as target and as recoil detector in an experiment investigating the diffraction dissociation of photons on hydrogen, ..gamma..p ..-->.. Xp. The TPC, which consists of two cylindrical drift regions each 45 cm in diameter and 75 cm long, measures the polar angle and the energy loss dE/dx of the recoil protons. Typically, at 15 atm of H/sub 2/ with 2 kV/cm drift field and 7 kV on the 35 ..mu.. sense wires, the drift velocity is about 0.5 cm/..mu.. sec and the spatial resolution +- 200 ..mu..

Observation of the Decay $\K_{L}^{0}\rightarrow\mu^{+}\mu^{-}

An experiment performed at the Brookhaven National Laboratory alternating-gradient synchrotron has yielded six events above negligible background which satisfy criteria for the decay K L0 -->µ+µ-. The K L0 flux, measured by means of the decay K L0 --> pi + pi -, leads to a value for the branching ratio Gamma (K L0 -->µ+µ-) / Gamma (KL-->all)=11 x 10-9