The study, by researchers at the University of Colorado at Boulder and Children's Hospital in Boston, indicates a typical person can safely listen to an iPod for 4.6 hours per day at 70 percent volume using stock earphones, according to Cory Portnuff, a doctoral researcher in CU-Boulder's speech language and hearing sciences department.
The researchers found that listening to music at full volume through an iPod for more than five minutes a day using stock earphones can increase the risk of hearing loss in a typical person
Typical individuals can tolerate about two hours a day of a decibel unit known as 91-dBA before risking hearing loss, Portnuff said. The term dBA stands for "A-weighted decibels, a scale that takes into account that the human ear has different sensitivities to different frequency levels,"
Loud sounds can stress and potentially damage delicate hair cells in the inner ear that convert mechanical vibrations, or sound, to electrical signals that the brain interprets as sound. "Over time, the hair cells can become permanently damaged and no longer work
No one set of earphones is more dangerous than another," he said. "While isolator style earphones are capable of producing higher levels of sound than earbuds, most people use them at a lower volume than earbuds because they block out background noise. It's important to monitor the level of volume control settings."
The EPA will remove PCBs and TCE from subsurface soils and remove
PCBs in two on-site buildings.
“This clean-up is absolutely critical because so many children are
potentially at- risk across the street at the Herbert Hoover Boys
& Girls Club,” said U.S. Rep.
Wm. Lacy Clay (D-MO).
the
agency plans a
thermally enhanced extraction of two toxins:
trichloroethylene (TCE), a chlorinated industrial solvent, and
polychlorinated biphenyls (PCBs), a cancer-causing chemical once
used in electrical transformers that were disassembled at a
building on the site.
The citizen advocacy group is calling for cleanup goals be expanded
to cover all areas impacted by Carter Carburetor, the treatment
technology to be proven to work on PCBs on similar sites and at
similar concentrations before use at the St. Louis site, the risk
assessment scenario expanded to include children of all ages and
the cleanup plan protect the health of children and area
residents.
Brain gene activity changes through life Studies track biochemical patterns from just after conception to old age Web edition : Friday, October 28th, 2011 Human brains all work pretty much the same and use roughly the same genes in the same way to build and maintain the infrastructure that makes people who they are, two new studies show.