When Sifrhippus sandae, the earliest known horse, first appeared in the forests of North America more than 50 million years ago, it would not have been mistaken for a Clydesdale.
It weighed in at around 12 pounds–and it was destined to get much smaller over the ensuing millennia.
Sifrhippus lived during the Paleocene-Eocene Thermal Maximum (PETM), a 175,000-year interval of time some 56 million years ago in which average global temperatures rose by about 10 degrees Fahrenheit. (more…)
*A new study finds that low concentrations of the chemical methylisothiazolinone has subtle but measurable negative effects on the neural development of tadpoles. The chemical is found in some cosmetics, although the study does not provide any evidence that cosmetics are unsafe for humans.*
PROVIDENCE, R.I. [Brown University] — Scientists, health officials, and manufacturers already know that a chemical preservative found in some products, including cosmetics, is harmful to people and animals in high concentrations, but a new Brown University study in tadpoles reports that it can also interrupt neurological development even in very low concentrations.
In the cosmetics industry, the biocide methylisothiazolinone or MIT, is considered safe at concentrations of less than 100 parts per million. Lab studies, however, have found that lower concentrations affected the growth of animal neurons. Picking up from there, the Brown researchers performed a series of experiments to investigate how 10 days of exposure at concentrations as low as 1.5 ppm would affect whole, living tadpoles as they develop. Their results appear in advance online in the journal Neuroscience. (more…)
*Engineers at Brown University have developed a system that cleanly and efficiently removes trace heavy metals from water. In experiments, the researchers showed the system reduced cadmium, copper, and nickel concentrations, returning contaminated water to near or below federally acceptable standards. The technique is scalable and has viable commercial applications, especially in the environmental remediation and metal recovery fields. Results appear in the Chemical Engineering Journal.*
PROVIDENCE, R.I. [Brown University] — An unfortunate consequence of many industrial and manufacturing practices, from textile factories to metalworking operations, is the release of heavy metals in waterways. Those metals can remain for decades, even centuries, in low but still dangerous concentrations.
Ridding water of trace metals “is really hard to do,” said Joseph Calo, professor emeritus of engineering who maintains an active laboratory at Brown. He noted the cost, inefficiency, and time needed for such efforts. “It’s like trying to put the genie back in the bottle.” (more…)
WASHINGTON — The deadly Russian heat wave of 2010 was due to a natural atmospheric phenomenon often associated with weather extremes, according to a new study. And while the scientists could not attribute the intensity of this particular heat wave to climate change, they found that extreme heat waves are likely to become increasingly frequent in the region in coming decades.
The research team drew from scientific observations and computer climate models to evaluate the possible roles of natural and human-caused climate influences on the severity of the heat wave. The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union. (more…)
Fireworks. Downtown Miami on July 4, 2007. Image credit: Marc Averette. Source: Wikipedia
Fireworks can be spectacular. However, the gas and smoke produced by the colorful explosions carry extremely high levels of toxic particles, according to a study by Audrey Smargiassi, a professor at the Université de Montreal Department of Environmental and Occupational Health.
Smargiassi conducted one of the first studies examining the composition of the emitted gases and the concentration of the particles. In addition, her study is unique as she collected her data below the fireworks display where spectators usually stand. Previous studies usually collected data from nearby rooftops.
The study was conducted in 2007 during nine separate shows presented at La Ronde amusement park where 5.7 million spectators attend an international fireworks competition every summer. (more…)
