Male and female birds often show differences in body size, with males typically being larger. Some birds, like many ratites – large, flightless species such as emus and cassowaries – are the opposite, with the females towering over the males. 

But some extinct ratites, among the largest female birds in the world, were almost twice as big as their male mates. A new paper says that the size difference in giant moa was not due to any specific environmental factors but instead evolved as a result of scaling-up of smaller differences in male and female body size shown by their smaller-bodied ancestors.

New research has questioned the reliability of neuroscience studies, concluding that most had an average power of around 20 percent – a finding which means the chance of the average study discovering the effect being investigated is only one in five. 

The conclusions neuroscience papers drew could be wrong due to small sample sizes, the authors say.

Many factors can push a wild animal population to the brink of collapse and ecologists have long sought ways to measure the risk of such a collapse.

Last year, MIT physicists demonstrated that they could numerically predict a population's risk of collapse by monitoring how fast it recovers from small disturbances, such as a food shortage or overcrowding. However, this strategy would likely require many years of data collection.

The same research team writing in Nature now describes a new way to predict the risk of collapse, based on variations in population density in neighboring regions. Such information is easier to obtain than data on population fluctuations over time, making it potentially more useful, according to the researchers.

Violent crime is undercounted or overcounted, depending on who you ask. Some statistics count gun violence twice, for example, as a criminal getting shot and a police officer doing the shooting.

On the other side, in a paper published in the Canadian Journal of Criminology and Criminal Justice, Wayne State University Ph.D. student Zavin Nazaretian and David M. Merolla, assistant professor of sociology, say that "capping" — which only allows survey respondents to represent a maximum of three incidents per crime type regardless of how many incidents they report — is undercounting violent crime by 87 percent and household crime by 36 percent.

Our sun will one day become a faint white dwarf star - but prior to that, for a few tens of thousands of years as its atmosphere is blown away into space  it could be surrounded by spectacular and colorful glowing clouds of ionized gas known as planetary nebulae.

"What are the radiation doses to airplane passengers from the intense bursts of gamma-rays that originate from thunderclouds?" researchers asked at a press conference during the European Geosciences Union in Vienna today.