Recently in Being Human

Michael Marshall, environment reporter

If reports this week are to be believed, the entire anatomically modern human population descends from ancestors who lived in southern Africa. This flies in the face of a mass of evidence that the cradle of humanity was east Africa, probably somewhere near the famous Great Rift valley. So where did we really come from?

The idea of a southern Africa origin comes from a study of the genetics of African hunter-gatherer groups. Brenna Henn of Stanford University in California and colleagues genotyped people from seven groups, including Khoisan-speakers from the Hadza and Sandawe populations in Tanzania and click-speaking ǂKhomani Bushmen of South Africa, and found many differences.

Nature News explains:

These sorts of differences have allowed geneticists to calculate relationships and moments of evolutionary divergence... The team used the geographic locations of the genetically diverse groups of people to determine where humans might first have emerged.

The researchers found genetically diverse groups in central and eastern Africa, but most were in the south of the continent. As Henn told the BBC:

Populations in southern Africa have the highest genetic diversity of any population, as far as we can tell. So this suggests that this might be the best location for [the origins] of [anatomically] modern humans.

Debora MacKenzie, reporter  

Peter Aldhous, San Francisco bureau chief

(Image: Rex Features)

What do George W. Bush and Osama Bin Laden have in common? Both may have unwittingly revealed their decisions to launch violent actions through subtle shifts in their use of language.

"It doesn't matter which team you're on," James Pennebaker, a psychologist at the University of Texas at Austin, claimed at the annual meeting of the American Association for the Advancement of Science. "If your team is going to war, there are these linguistic shifts."

Pennebaker is one of several researchers working with the US Department of Homeland Security on the Comparative Case Studies of Radical Rhetoric project, which is analysing English translations of statements issued by al-Qaeda and al-Qaeda in the Arabian Peninsula, alongside those released by two groups with similar radical Islamic philosophies, but which have not resorted to violence. The ultimate goal is to help intelligence analysts predict impending acts of terrorism.

Jessica Hamzelou, reporter

Ferris Jabr, reporter

When avid sports fans sit down to watch a game on TV, they are not really on the couch: they are stepping up to the plate, sprinting down the field, gliding over the ice - they are right there, shoulder pad to shoulder pad with their favourite players.

For some die-hard fans, watching a game is apparently such an immersive experience that they, well, die of the excitement. Exhilarating matches can really get your heart going; unfortunately, they can also permanently silence its beating.

Robert Kloner, a cardiologist at the University of Southern California, analysed cardiac deaths in Los Angeles county during two Super Bowls: an intense 1980 match in which the much-loved Los Angeles Rams lost to the Pittsburgh Steelers at the Rose Bowl in Pasadena, California and a more predictable 1984 game in which the Los Angeles Raiders gained an early lead and defeated the Washington Redskins in Tampa, Florida.

Kloner and his colleagues found that deaths due to heart failure in Los Angeles rose during the 1980 Super Bowl for both men and women - and especially for people over 65. Conversely, cardiac deaths decreased during the 1984 Super Bowl. The 1980 loss, Kloner reasons, literally broke the hearts of some fans in LA, especially if they had underlying heart conditions. But 1984's unsurprising victory hardly tugged anyone's heartstrings.

"There are many well-known chronic risk factors for cardiac deaths - smoking, obesity, diabetes," Kloner explains, "but there is also evidence for acute risk factors that trigger a cardiac event."

Earthquakes are one good example of acute risk factors for cardiac deaths, Kloner says, and he is interested in discovering other heart-stopping global phenomena. He decided to investigate the Super Bowl after reading a 2008 New England Journal of Medicine study that found alarming rates of cardiac emergencies in Germany during the World Cup.

"Fans develop an emotional attachment to their favourite team, which becomes like part of the family," Kloner says. "Think about how a parent feels when watching a child in a school sporting event: if junior has a bad game, or makes a bad play, or the play is intense, it can lead to emotional stress. The same thing can occur in the avid fan supporting their beloved team."

This is perhaps the most intriguing aspect of Kloner's study. When we think of sports-related injuries and health risks, we typically think of concussions, dislocated shoulders and torn anterior cruciate ligaments (ACLs). But patterns of cardiac deaths in sports fans raise to the surface a latent and overlooked concern: how watching sports can curse the body by enchanting the mind. An avid sports fan has a heart that beats not for a single individual, but for an entire team - a strain that is sometimes too great to sustain.

Journal reference: Clinical cardiology, DOI:10.1002/clc.20876

Ferris Jabr, reporter

In the past few years, some researchers have explored whether warfare and societal collapse might be explained in part by swings in climate.

A 2007 study found that periods of cold weather preceded 12 of 15 major conflicts in China's ancient dynasties. The frost would have created food shortages, the study suggested, which would have inspired rebellions and made communities more vulnerable to invasion. More recently, a study in Science argued that dramatic shifts in climate would have affected agriculture, contributing to the fall of the Roman Empire.

But what about the opposite effect? Can humanity's skirmishes change the climate?

Jessica Hamzelou, reporter

Barack Obama speaks about healthcare reform legislation at the American Nurses Association House of Delegates (Image: Rex Features)

The House of Representatives voted yesterday to repeal Obama's bill on healthcare reform.

The vote was won by 245 to 189, as three Democrats joined all 242 Republicans in voting to scrap the Affordable Care Act which was passed by Congress last year.

Those who voted for the repeal argue that making the healthcare system more efficient will result in job losses, and that businesses forced into offering health insurance to employees will suffer.

The bill will cripple small businesses, Republican representative Joe Wilson told the Boston Globe:

The liberal healthcare takeover destroys jobs, limits freedoms, and expands big government

Andy Coghlan, reporter

Wendy Zukerman and David Cohen

There's been a slight over-reaction in the media to the publication of a study exploring the fascinating effects of the drug ketamine on people's perception of reality.

Most reports got bogged down in hyped outrage over paying students £250 to take part in the trial, and the side effects experienced by one participant. Paying participants is a common practice in scientific research and risks would have been weighed by an ethical review board. The side effects reported in a local Cambridgeshire newspaper seemed to have stirred things up, even though that report also admits it is not the first of its kind - at least two other studies involving ketamine were conducted at Cambridge over the last two years.

But there's a far more interesting story here.

Peter Aldhous, San Francisco bureau chief

If you had any doubts that science faces a rough ride in the next Congress, due to start work in January, watch this video.

The incoming Republican majority in the House of Representatives has selected the National Science Foundation (NSF) as the first target for a "YouCut Citizen Review", in which ordinary Americans are being asked to identify "wasteful spending that should be cut".