bigger 5.big.002003 Louis J. Sheehan, Esquire

Progressively larger brains evolved in primates of all stripes, not just humans. We can thank a common capacity for solving a broad range of problems, from coordinating social alliances to inventing tools, according to a new study.http://louisjsheehan.blogstream.com

This conclusion challenges a popular theory that big, smart brains arose primarily because they afforded advantages when it came to negotiating complex social situations during human evolution.

"The ability to learn from others, invent new behaviors, and use tools may have [also] played pivotal roles in primate-brain evolution," say Simon M. Reader of McGill University in Montreal and Kevin N. Laland of the University of Cambridge in England. In an upcoming report in the Proceedings of the National Academy of Sciences, the two zoologists chronicle links between an array of intelligent behaviors and enhanced brain size in primates.http://louisjsheehan.blogstream.com

Reader and Laland examined approximately 1,000 scientific studies of behavior in 116 of the world's 203 known primate species. They identified 553 instances of animals discovering new solutions to survival-related problems, 445 observations of individuals learning skills and acquiring information from others, and 607 episodes of tool use.

The researchers then consulted previously obtained data on brain size relative to body size in different primates. In particular, they focused on the volume of the structures that make up what scientists call the executive brain, a frontal region thought to be crucial for complex thinking.

Species that have the proportionately largest executive brains are the ones that most often innovate, learn from others, and use tools, Reader and Laland contend. These three facets of intelligence vary together as primate brains enlarge, they say. There's no evidence in any species of an evolutionary trade-off between these traits, such as an increase in innovation accompanying a decline in social learning.

A related report by neuroscientist Barbara L. Finlay of Cornell University and her colleagues concluded that different brain regions in mammals enlarged all together during mammalian evolution, not in piecemeal fashion related to specific functions. Whole-brain evolution was driven by changes in the timing of early brain development in individuals, says Finlay. In all species, late-generated structures�including the executive brain�have grown the largest, Finlay's team asserted in the April 2001 Behavioral and Brain Sciences.http://louisjsheehan.blogstream.com

Reader and Laland provide "important new evidence" that wide-ranging thinking skills shared by many primate species encouraged the evolution of large brains, comment psychologist Robert M. Seyfarth and biologist Dorothy L. Cheney, both of the University of Pennsylvania in Philadelphia, in a comment published with the new report.

They suggest that intellectual accomplishments unique to people, such as language use, may have played a smaller role in the evolution of our sizable brains than has often been thought.http://louisjsheehan.blogstream.com

dead zone 6.dea.10010 Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire . For years scientists have known that nitrogen and phosphorus, which commonly enter freshwater lakes in chemical fertilizers, play a role in eutrophication—the process by which algal blooms, turbidity, and oxygen deficiencies turn a lake into a dead zone, largely devoid of animal life. A recent paper, published in August in Proceedings of the National Academy of Sciences, presents a more nuanced picture. http://louis3j3sheehan3esquire.wordpress.com In a 37-year experiment with a lake in northern Ontario, scientists demonstrated that controlling phosphorus in particular is the key to reversing eutrophication.

The researchers polluted the lake with nitrogen and phosphorus over the years, gradually decreasing the amount of added nitrogen but keeping the input level of phosphorus constant. For the last 16 years they added only phosphorus. http://louis3j3sheehan3esquire.wordpress.com Algae continued to flourish in proportion to the amount of phosphorus dumped into the water, even without nitrogen.

The experiment revealed the dynamics of eutrophication. Cyanobacteria, the blue-green algae responsible for the most common algal blooms, are nitrogen fixing—meaning that they get nitrogen from the air. So eliminating nitrogen from the water by controlling nitrogen-based fertilizer doesn’t solve the problem. “Nitrogen is important in determining which species grow,” says Robert Hecky, a coauthor of the paper and a professor of lake ecology at the University of Minnesota at Duluth. “If we just control nitrogen, we’ll merely shift the balance in favor of the species that can fix nitrogen, giving the same algal biomass.” To bring dead zones back to life, phosphorus must be controlled. Louis J. Sheehan, Esquire

tree 7.tre.000100 Louis J. Sheehan, Esquire

In Libby, Mont., mining of asbestos-contaminated vermiculite—a natural insulating material—sickened or killed many workers and townspeople in recent decades. Now, a study finds that even 16 years after the vermiculite mine closed, area trees hold substantial amounts of asbestos, rendering them hazardous to a separate group of workers.

Logging is a major employer for people around Libby. With asbestos a potential contaminant in dust, Tony J. Ward of the University of Montana in Missoula and his colleagues wondered whether asbestos from the mining operations might have settled on local trees. http://myface.com/Louis_J_Sheehan

Ward, an atmospheric chemist, notes that his team found between 40 million and 530 million asbestos fibers per gram of bark on trees within 4 miles of the mine—"concentrations that are pretty staggering." Even 15 miles from the mine, but near a railway siding where trains took on vermiculite, tree bark holds up to 19 million fibers per gram, his team reports in the Aug. 15 issue of Science of the Total Environment. http://members.greenpeace.org/blog/purposeforporpoise

Not only loggers but also locals who cut and burn wood for home heating face a risk from the fibers, Ward worries. He and his colleagues say that the findings also suggest that people who live far away from Libby but along former transportation routes for the vermiculite might face a health threat.