Can weather affect the way people vote?
A new US study suggests a connection between changes in temperature and that country's voting behaviour, finding warmer weather in states was related to increases in voter turn-out - and votes for the incumbent party.
Voter behaviour data from each state was collected for all US presidential elections from 1960 to 2016 and compared to the difference between maximum temperature on voting day and that of the previous election day.
"We found that for every 10C increase in temperature, voter turnout increased by 1.4 per cent," said Jasper Van Assche, a researcher at Belgium's Ghent University, and whose study has been published in Frontiers in Psychology.
"Although these effects are rather small compared to the 'usual suspects' that predict voting, they might play a role in close races."
He and his co-authors have gone as far as suggesting a 10C increase in temperature may have made Al Gore the 43rd US President instead of George W Bush, as Gore might have won in Florida.
Van Assche stressed his results were not affected by other factors that could influence voter behaviour.
"Importantly, the relationship between voter behaviour and turnout remained true even when we took into account the 'usual suspects' that can have an effect - the president being available for reappointment, the incumbent president being elected or not, presidential approval ratings, whether the president's party had a majority in Congress during the two last years, and change in state gross domestic product (GDP), amongst others."
The politics of... algae
While single-celled organisms typically only make it into political discussion during insults, it turns out that modelling their behaviour may give researchers a better handle on how political movements survive and spread.
In a new study, researchers have modelled systems where strategies or ideologies compete for members.
By varying the extent to which members of a given system worked offensively or defensively, trying to convert individuals to their "side" or trying to keep similar individuals, they found some general principles that may begin to explain how differing strategies play out.
"The original angle for this was not a political slant. It was actually algae," said study author Eric Libby, a unicellular microbes researcher at the US-based Santa Fe Institute.
But, he noted, "I think that the political handle on this is probably more intuitive."
At first, the researchers had been looking at how algae evolve differing complex life cycles, such as which nutrients to absorb.
But after a working group with their collaborators, they saw it might help explain dynamics in a population where two groups compete for resources - in this case, voters.
In the original simulation model developed, which included just two distinct groups, individuals displaying one ideology might adopt the other if they were around enough people with the opposite beliefs seeking to influence them.
Over time, the researchers found that when two competing ideologies squared off with predominantly offensive strategies, many individuals would convert from one side to the other, and both parties would persist.
Meanwhile, when both ideologies were more defensive, rather than leading to a stalemate, the less defensive group disappeared entirely, as a small initial loss would ultimately be amplified.
A 50/50 offence-defence mix was found to be the best strategy.
But when a third party was added to the mix, the winning strategy was one that used a level of offence higher than one opponent but lower than the other - and there was no single best strategy.
"If you have multiple strategies competing, there doesn't seem to be an optimal solution," Libby explained.
"It really depends on who else you're competing against."
Blue-eyed people share a common ancestor
Scientists have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today.
"Originally, we all had brown eyes," explained Professor Hans Eiberg, of the University of Copenhagen.
"But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a switch which literally turned off the ability to produce brown eyes."
The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin.
The "switch," which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but limits its action to reducing the production of melanin in the iris - effectively "diluting" brown eyes to blue.
The switch's effect on OCA2 is therefore quite specific: and If the gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour - a condition known as albinism.
Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes.
"From this we can conclude that all blue-eyed individuals are linked to the same ancestor," Eiberg said.
"They have all inherited the same switch at exactly the same spot in their DNA."
Brown-eyed individuals, by contrast, had considerable individual variation in the area of their DNA that controls melanin production.
Eiberg and his team examined mitochondrial DNA and compared the eye colour of blue-eyed individuals in countries as diverse as Jordan, Denmark and Turkey.
His findings are the latest in a decade of genetic research, which began in 1996, when Eiberg first implicated the OCA2 gene as being responsible for eye colour.