Fifteen years ago, a study showed that the brains of London cab drivers had an enlargement in the hippocampus, a brain area associated with navigation. But questions remained: Did the experience of navigating London's complex system of streets change their brains, or did only the people with larger hippocampi succeed in becoming cab drivers?

Restoring testosterone production in men may be as effective as replacing it, without compromising their fertility. Two phase III clinical trials show that a drug that restores the body's natural production of testosterone has no negative effect on a man's sperm count while a topical testosterone gel causes a significant drop. The findings, which are published in BJU International, could change the way men are treated for low testosterone.

Science fiction stories often suggest that ETs, and our future selves also, would be expansionist, colonizing the galaxy, taking over worlds, and so forth. It's natural enough, because we are expansionist ourselves. But it's actually quite easy to see that ETs simply can't have expanding populations, at least not for very long. Not if they are anything like us. 

It's a simple calculation which I covered before. If their doubling time is once a century, say (for  ease of calculation) - then in a thousand years, their population multiples by a little over a thousand (two to the power ten). So after two thousand years it has multiplied by a million, by a billion after three thousand years and so on.

Sorry, I accidentally made two copies of this article with different titles. And both have comments, so not sure what to do.

Unless you want to read the comments here, please visit the newer copy, Why ETs Won't Need to Colonize or Expand.

We are often told how bad it is to keep sitting at the computer, but one good outcome at least is how some much interesting science news comes one’s way.  One item dated 19 October 2015 from Radboud University (Nijmegen, the Netherlands) states:

Jupiter's moon Europa is believed to possess a large salty ocean beneath its icy exterior, and that ocean, scientists say, has the potential to harbor life. Indeed, a mission recently suggested by NASA would visit the icy moon's surface to search for compounds that might be indicative of life. But where is the best place to look? New research by Caltech graduate student Patrick Fischer; Mike Brown, the Richard and Barbara Rosenberg Professor and Professor of Planetary Astronomy; and Kevin Hand, an astrobiologist and planetary scientist at JPL, suggests that it might be within the scarred, jumbled areas that make up Europa's so-called "chaos terrain."

One just has to be able to accept certain scientific liberties to be a fan (addict?) of The Walking Dead. It is well worth it, since it's the most entertaining hour on television.

For example, I always wondered why the characters are routinely covered with zombie blood, guts, and other slime, all of which routinely runs down into their mouths, *and* into open wounds, yet they never catch the virus that started the apocalypse. One character even stuck his hand in the mouth of one of the things that was trying to bite him, and ripped its head off. *That* was OK, yet, if he had sustained a nibble on a cuticle during this attempt, he would have caught it turned into one of them.

This year to celebrate Halloween, Digital Science have compiled their top five spooky scientific research papers.

Early life stress is a major risk factor for later episodes of depression. In fact, adults who are abused or neglected as children are almost twice as likely to experience depression. 

Scientific research into this link has revealed that the increased risk following such childhood adversity is associated with sensitization of the brain circuits involved with processing threat and driving the stress response. More recently, research has begun to demonstrate that in parallel to this stress sensitization, there may also be diminished processing of reward in the brain and associated reductions in a person's ability to experience positive emotions.

Quebec City, October 27, 2015--After more than a century of speculation, researchers have finally proved that American eels really do migrate to the Sargasso Sea to reproduce. A team supervised by Professor Julian Dodson of Université Laval and Martin Castonguay of Fisheries and Oceans Canada reports having established the migratory route of this species by tracking 28 eels fitted with satellite transmitters. One of these fish reached the northern boundary of the Sargasso Sea, the presumed reproduction site for the species, after a 2,400 km journey. Details are published in the latest edition of Nature Communications.