Genes and signals: Ptashne, M., Gann, A.

Mark Ptashne: our current picture

In 1980 Mark Ptashne published a review entitled How λ repressor and Cro work followed by another, in 1988, called How eukaryotic transcriptional activators work. The bold — almost, some might feel, naïve — ambition these titles betray is unashamedly the author’s: to generate a coherent picture of how genes are switched on and off. Mark Ptashne’s approach has always been transparent. During gro...

Jasmonate, genes, and fragrant signals.

Irrepressible: An Interview with Mark Ptashne

While winter storms crippled almost every state fromWisconsin to Florida, our own force of nature blew into California in January in the compact human form of Mark Ptashne (Fig 1). Mark, who holds the Ludwig Chair of Molecular Biology at Sloan-Kettering in New York, had arrived to give a series of seminars on the West Coast. And if that weren’t enough, he also came prepared for a soirée, with h...

Decorrelation of L- and M-cone signals.

For a large sample of broadband lights reflected from natural and man-made objects, the correlation between L- and M-cone absorptions was found to be 0.99. The correlation between L + M and L - M signals was 0.21. The early recombination of cone signals in the visual system thus leads to a substantial decorrelation.

Genetic Artificial Neural Networks (gann) Modeling

Genetic algorithms and neural networks have received great acclaim in the computer science research community since the 1980s. For the most part, this results from successful applications of these new computing models, but also, because the concepts share the spirit of a movement that goes beyond science. The major principle of this movement is the idea that for a broad set of complex problems ...