The possible effect of contrails in modifying the weather is reconsidered in the light of information obtained from ground-level contrails in Alaska. It appears likely that inadvertent cloud seeding b y jet aircraft may be of the same order of magnitude as that attained in commercial cloud seeding operations. Further investigation is needed; but in the meantime, the possibility of contrail cont...

[1] Multiple end-member spectral mixture analysis (MESMA) was applied to the Clementine UVVIS global 1 km multispectral data set, and the resulting highland material fraction image was used to investigate highland contamination of mare surfaces by impact cratering. MESMA decomposes each pixel with the number of end-members fewer than the number of the spectral bands of Clementine UVVIS data. Th...

Background and Aims: World Health Organization Global Polio Laboratory Network (GPLN) plays a critical role in the Global Polio Eradication Initiative. Cell culture methods (mostly RD and L20B cell lines) have been used for Enteroviruses and polioviruses isolation, respectively. Cross-contamination among L20B and RD cell lines causes the problem in accuracy of poliovirus surveillance and decrea...