Another week done. It’s Friday morning and here are the links. The news is full of what happened in Woolwich this week, this post isn’t. Some people did a terrible thing, a man died, a child doesn’t have a father. That’s sad and awful enough, it doesn’t need any commentary today.

So links..

1) Electric shocks to brain seem to help people with maths problems. Not sure that this is something I would have liked at school but I’m rubbish at maths, unlike my Ma and Ben.

People who struggle with maths problems might fare better after a course of gentle electric shocks to the brain, scientists have claimed.

Psychologists at Oxford University found that students scored higher on mental arithmetic tasks after a five-day course of brain stimulation.

If future studies prove that it works – and is safe – the cheap and non-invasive procedure might be used routinely to boost the cognitive power of those who fall behind in maths, the scientists said. Researchers led by Roi Cohen Kadosh zapped students’ brains with a technique called transcranial random noise stimulation (TRNS) while they performed simple calculations, or tried to remember mathematical facts by rote learning.

2) HS2 is a pup and we don’t really need it. And if we’re going to have it, could we start in the North and bring it down south last. We have plenty of transport links and infrastructure in London (ok some of it isn’t great but we have it) and the North doesn’t. We need to start thinking about the whole country not just London and the South East. I say this this as a proud Londoner!

Certainly, the leaders of Birmingham, Sheffield and Manchester have welcomed HS2. For them it is either £1,000 a head from every taxpayer in Britain or nothing. They would be mad to refuse. The people of the Midlands and north were never asked what else they might do with such an enormous sum. If it were their money they would not touch it with a bargepole. No one offered them a Birmingham subway, a high-speed Manchester-Sheffield link or a Nottingham-Derby-Stoke motorway. No one did a rate of return on extending the M65 down the congested Aire valley in Yorkshire. To Westminster such projects are for peasants: they come nowhere near London.

3) On Monday, there were lots of people on the radio essentially saying “I’m not homophobic, but gay marriage will change the definition of marriage as we know it.” So I think it’s worth linking to this again.

4) and Peter Tatchell on the subject.

For me, banning same-sex marriage is homophobic discrimination. I resent being told that I’m not allowed to marry because I am gay. I want to be able to choose – and refuse. In a democracy, everyone should be equal before the law. This includes the right of same-sex couples to marry and be just as happy – or miserable – as married heterosexuals.

5) Miss Piggy Q & A in Saturday’s Guardian. One of my role models!

 What is your favourite smell?
Wet amphibian

6) Michael Pollan on the microbes that live on and in us. Fascinating.

Your microbial community seems to stabilize by age 3, by which time most of the various niches in the gut ecosystem are occupied. That doesn’t mean it can’t change after that; it can, but not as readily. A change of diet or a course of antibiotics, for example, may bring shifts in the relative population of the various resident species, helping some kinds of bacteria to thrive and others to languish. Can new species be introduced? Yes, but probably only when a niche is opened after a significant disturbance, like an antibiotic storm. Just like any other mature ecosystem, the one in our gut tends to resist invasion by newcomers.