Do it for fun, but not for profit

Just a couple of choice selections from the cornucopia which is Jess Riedel's blog.

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American drone for covert underwater warfare

Trident will be obsolete before the next-generation hits the water

"For half a century, big missile submarines, known as boomers, have been arguably the most decisive weapon systems in modern warfare – the queen on the strategic chessboard – because of their capacity to remain unseen until the critical moment, unleashing enormous destructive force without warning.

"Now that dominant position is under threat. A submarine can hide from a few noisily obvious ships and planes, but it is harder to hide from a swarm of small, virtually undetectable drones. The robots being developed here can potentially be made cheap and expendable, and capable of being deployed in large numbers to cover vast expanses of sea. Once fully developed, they could tilt the balance of power beneath the waves – much as airborne drones are already doing in the sky.

"It is unclear how far other countries have got with underwater drone technology; it is known that the Russian navy is working on it intensively."

I foresee an arms race where the ballistic missile submarine deploys a screen of 'drone fighters' to take out the enemies underwater surveillance drones. Good luck with that.

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Propensity to exercise and increased lifespan are correlated but not causal

"Observational studies report a strong inverse relationship between leisure-time physical activity and all-cause mortality. Despite suggestive evidence from population-based associations, scientists have not been able to show a beneficial effect of physical activity on the risk of death in controlled intervention studies among individuals who have been healthy at baseline. On the other hand, high cardiorespiratory fitness is known to be a strong predictor of reduced mortality, even more robust than physical activity level itself.

"Here, in both animals and/or human twins, we show that the same genetic factors influence physical activity levels, cardiorespiratory fitness, and risk of death. Previous observational follow-up studies in humans suggest that increasing fitness through physical activity levels could prolong life; however, our controlled interventional study with laboratory rats bred for low and high intrinsic fitness contrast with these findings.

"Also, we find no evidence for the suggested association using pairwise analysis among monozygotic twin pairs who are discordant in their physical activity levels. Based on both our animal and human findings, we propose that genetic pleiotropy might partly explain the frequently observed associations between high baseline physical activity and later reduced mortality in humans."

What this is saying is that the same set of good genes are both encouraging higher physical activity levels and giving you a longer life. If you happen to have the good genes and for some reason you're not physically active ('monozygotic twin pairs who are discordant in their physical activity levels') you still get the long life.

This is not genetic determinism. Your genes give you a set point: a certain lifespan, body-plan, weight; your choices of diet and exercise will have a varying effect, but only around that set point - not arbitrarily.

Riedel comments, "Stunning if true. Think this will slowdown our culture’s obsession with exercise for health? Me neither."