The former city and now archaeological site called Cantona in the highlands east of Mexico City appears to have been abandoned nearly 1,000 years ago as a result of a prolonged dry spell that lasted about 650 years, according to a new study by geography graduate student Tripti Bhattacharya and professor Roger Byrne.
The flip side of Heisenberg's uncertainty principle, the energy time uncertainty principle, establishes a speed limit for transitions between two states. UC Berkeley physical chemists have now proved this principle for transitions between states that are not entirely distinct, allowing the calculation of speed limits for processes such as quantum computing and tunneling.
Thanks to historical data preserved in UC Berkeley's libraries, campus botanists have been able to compare tree survey data from the 1920s and '30s with forest service data today. They find a decline in large trees and an increase in the density of small trees in forests throughout the state. The large tree decline seems to be caused by water stress.
Is Earth at the dawn of a new geological epoch dominated by human-influenced geologic and environmental change? Anthony Barnosky is part of a group that proposes that this new era, called the Anthropocene, indeed began at the start of the nuclear era with the 1945 Trinity nuclear bomb test in New Mexico.
A tiny sliver of plutonium safely stored on the UC Berkeley campus is making news for its connection to a momentous point in history. Nuclear scientists have recently determined with near certainty that the plutonium was created by a team led by the late UC Berkeley chemist Glenn Seaborg as part of the Manhattan Project.
Two and a half million years ago, our hominin ancestors in the African savanna crafted rocks into shards that could slice apart a dead gazelle, zebra or other game animal. Over the next 700,000 years, this butchering technology spread throughout the continent and, it turns out, came to be a major evolutionary force, according to new research that combines the tools of psychology, evolutionary biology and archaeology.
Berkeley scientists show that the effects of chronic stress on fertility persist long after the stress is gone. This is because a hormone that suppresses fertility, GnIH, remains high even after stress hormone levels return to normal. In rats, they successfully blocked the hormone gene and restored normal reproductive behavior, suggesting therapeutic potential for stressed humans and animals in captive breeding programs.
UC Berkeley psychologist Fred Theunissen's work on songbirds could help improve hearing aids to allow people to home in on specific sounds in noisy environments, a particular problem for the hard of hearing. He and his graduate students study zebra finches, which are especially adept at listening in crowded, noisy environments, and developed an algorithm for reducing distortion in hearing aids.
Amid the amazing biodiversity of the Indonesian island of Sulawesi lives a 5-gram frog that gives direct birth to tadpoles, without ever laying eggs. This unique reproductive strategy, found in a group of fanged frogs endemic to the island, is described for the first time by UC Berkeley herpetologist Jim McGuire and colleagues from Indonesia and Canada.