Archive for electronic signature

chain of lynx and drove of hares

Posted in Books, Kids, pictures, R, Statistics with tags , , , , , , , , , on February 27, 2020 by xi'an

A paper (and an introduction to the paper) in Nature this week seems to have made progress on the existence of indefinite predator-prey cyles. As in the lynx/hare dataset available on R. The paper is focusing on another pair, an invertebrate and its prey, an algae. For which the authors managed a 50 cycle sequence. What I do not get about this experiment is how the cycle can be tested via a rigorous statistical experiment.

“…the predator–prey system showed a strong tendency to return to the dominant dynamical regime with a defined phase relationship. A mathematical model suggests that stochasticity is probably responsible for the reversible shift from coherent to non-coherent oscillations, a notion that was supported by experiments with external forcing by pulsed nutrient supply.”

As I had not renewed my subscription to Nature in time, I could not check the additional material for details, but the modelling seems to involve a wavelet decomposition of the bivariate time series, with correlations between the two series…

copyright antiques and antics…

Posted in Books, Kids, pictures, University life with tags , , on August 7, 2015 by xi'an

Handwritten notes by E. GaloisI just cannot understand why publishers persist in requesting from us authors copyright agreements and even less  handwritten copyright forms that have to be sent back to them instead of via a simple email agreement or at least an electronic form. And because I cannot fill most those forms on line, it annoys me no end if only because it involves several physical steps, hence wasting my time. It would be just so easy to set an electronic copyright agreement if the publishers were under any form of pressure to do so. Hence I encourage everyone (sharing this irk!) to return a reply like the following one to each copyright request:

…why should I waste time printing, filling, scanning, and sending back this form in an era when electronic forms and signatures do exist and are accepted for legal matters? Commercial publishers request such paper antiques because they cannot be pressured into creating the proper electronic medium to handle copyright transfers.