Cerebrum

Subdural Haematoma

This usually occurs as the result of trauma and in such a situation is referred to as ‘acute subdural haematoma’. It is the deadliest of all head injuries.

Brain injury occurs because blood filling the area increases pressure and exerts enough force upon the brain to begin damaging the tissue. Hopefully it can be drained before this happens but more often than not, that isn’t the case.

Less frequently (and particularly in the elderly) they may occur after a very small head injury and persist unnoticed for weeks - this is the chronic presentation of subdural haematoma.

Life on Earth likely started 4.1 billion years ago, much earlier than scientists thought

UCLA geochemists have found evidence that life likely existed on Earth at least 4.1 billion years ago – 300 million years earlier than previous research suggested. The discovery indicates that life may have begun shortly after the planet formed 4.54 billion years ago.

“Twenty years ago, this would have been heretical; finding evidence of life 3.8 billion years ago was shocking,” said Mark Harrison, co-author of the research and a professor of geochemistry at UCLA.

“Life on Earth may have started almost instantaneously,” added Harrison, a member of the National Academy of Sciences. “With the right ingredients, life seems to form very quickly.”

The new research suggests that life existed prior to the massive bombardment of the inner solar system that formed the moon’s large craters 3.9 billion years ago.

“If all life on Earth died during this bombardment, which some scientists have argued, then life must have restarted quickly,” said Patrick Boehnke, a co-author of the research and a graduate student in Harrison’s laboratory.

Scientists had long believed the Earth was dry and desolate during that time period. Harrison’s research – including a 2008 study in Nature he co-authored with Craig Manning, a professor of geology and geochemistry at UCLA, and former UCLA graduate student Michelle Hopkins – is proving otherwise.

“The early Earth certainly wasn’t a hellish, dry, boiling planet; we see absolutely no evidence for that,” Harrison said. “The planet was probably much more like it is today than previously thought.”

The researchers, led by Elizabeth Bell – a postdoctoral scholar in Harrison’s laboratory – studied more than 10,000 zircons originally formed from molten rocks, or magmas, from Western Australia. Zircons are heavy, durable minerals related to the synthetic cubic zirconium used for imitation diamonds. They capture and preserve their immediate environment, meaning they can serve as time capsules.

The research is published today in the online early edition of the journal Proceedings of the National Academy of Sciences.