A new study has found that cities with the largest increases in immigration between 1990 and 2000 experienced the largest decreases in rates of homicide and robbery. The findings suggest that immigration may be partially responsible for the drop in crime during the decade, the author says. The study appears in Social Science Quarterly.

Drawing from the FBI's Uniform Crime Reports and U.S. Census data, University of Colorado sociologist Tim Wadsworth analyzed 459 cities with populations of at least 50,000. Wadsworth measured immigrant populations in two ways: those who are foreign-born and those who immigrated within the previous five years.

Writing in American Antiquity, researchers from Arizona State University and North Carolina State University say archaeologists can use computational modeling to study the long-term effects of varying land use practices by farmers and herders on landscapes.

By using these techniques, archeologists can develop alternative computerized scenarios that can be compared with traditional archaeological records, possibly enhancing previous findings of how humans and the environment interact.

Elevated levels of carbon dioxide predicted by models of climate change can drive increased production of fungal spores, including some associated with allergies and asthma, according to a new study in Environmental Health Perspectives.

Researchers have programmed an autonomous molecular "robot" made out of DNA to start, move, turn, and stop while following a DNA track.

The development could ultimately lead to molecular systems that might one day be used for medical therapeutic devices and molecular-scale reconfigurable robots---robots made of many simple units that can reposition or even rebuild themselves to accomplish different tasks.

Results of the research have been published in Nature.

The traditional view of a robot is that it is "a machine that senses its environment, makes a decision, and then does something---it acts," said Erik Winfree, associate professor of computer science, computation and neural systems, and bioengineering at Caltech.

By analyzing tiny variations in the isotopic composition of silver in meteorites and Earth rocks, scientists are putting together a timetable of how our planet was assembled 4.5 billion years ago. The new study, published in Science, indicates that water and other key volatiles may have been present in at least some of Earth's original building blocks, rather than acquired later from comets, as some scientists have suggested.

Compared to the Solar System as a whole, Earth is depleted in volatile elements, such as hydrogen, carbon, and nitrogen, which likely never condensed on planets formed in the inner, hotter, part of the Solar System. Earth is also depleted in moderately volatile elements, such as silver.

MIT neuroscientists writing in the Journal of Neurophysiology have developed a new method to analyze brain imaging data – one that may paint a clearer picture of how our brain produces and understands language.

Research with patients who developed specific language deficits (such as the inability to comprehend passive sentences) following brain injury suggest that different aspects of language may reside in different parts of the brain. But attempts to find these functionally specific regions of the brain with current neuroimaging technologies have been inconsistent and controversial.