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Materials that repel sharks could save lives . . . of sharks

A metal that reacts with seawater to produce an electric field may help keep sharks at bay. But the idea isn’t to protect humans from shark attacks. Just the opposite: scientists hope the metal will save sharks from senseless deaths in fishing nets.

An estimated 11 million to 13 million sharks die each year as “bycatch,” collateral damage in the hunt for other fish. Sharks grow slowly and can take many years to reach reproductive age, so their populations are being severely impacted by fishing.

In a recent study that offers hope for preventing some of these deaths, scientists from NOAA, four universities, and a research firm that develops shark repellents placed bars of the metal palladium neodymium in tanks holding juvenile sandbar sharks. The sharks avoided the metal bars and weren’t tempted by bait suspended within 12 inches of the bars. The study suggests that the metal could be used to ward sharks away from fishing gear.

Palladium neodymium is machinable and reasonably priced. But more study is needed to determine whether it can resist corrosion and remain effective as a shark repellent over long periods of time.

Where U.S. carbon dioxide emissions come from…and where they go.

A new system for mapping carbon dioxide emissions in the U.S. will help regulators figure out exactly where these emissions are coming from and how best to reduce them. Among human-produced gases that contribute to climate change, carbon dioxide is public enemy number one.

A group of researchers at Purdue University, led by atmospheric scientist Kevin Gurney, created the interactive mapping system. Called Vulcan, the system tracks the hourly output of carbon dioxide—emitted when fossil fuels such as coal and gasoline are burned—from factories, power plants and other sources across the country. Vulcan shows carbon dioxide emissions at a scale that is 100 times more detailed than previous maps.

Vulcan has already revealed that the southeastern U.S. is a much more important source of emissions than previously realized. Also, the maps reveal that much of the carbon dioxide gas emitted into the atmosphere gets blown toward the north Atlantic.

Animated versions of the map [see video below] show how emissions fluctuate from day to night, and from summer to winter. For example, scientists have discovered that some regions experience huge releases of carbon dioxide in the late winter. The Vulcan data is available for anyone to download. The researchers are also working on a mapping system called the Hestia Project, which will quantify carbon dioxide emissions around the planet.

A half-decade study to track the flu’s travels could lead to better vaccines

Where does the flu come from? Scientists at the University of Cambridge and the World Health Organization’s Global Influenza Surveillance Network tracked the migrations of flu viruses and discovered that the most common originate in East and Southeast Asia and spread in a distinctive pattern around the world. Understanding how these viruses evolve and travel will lead to better vaccines against flu epidemics that currently infect 5 to 15 percent of the world’s population each year.

Until this study was done, the global migrations of flu viruses were a mystery. To solve it, the scientists analyzed 13,000 samples of influenza A (H3N2) virus—the most common type of flu—collected worldwide by the surveillance network to determine when these strains arrived at various locations between 2002 and 2007.

Because the flu evolves so quickly, selecting the strains to include in next year’s flu vaccines is a challenge. Now surveillance networks and vaccine developers can focus on Asia, which seems to be the birthplace of ever-evolving flu viruses. These viruses typically reach Europe and North America six to nine months later, and end up in South America a few months after that. Fortunately, it’s usually a one-way trip.

The study will be published on April 18 in the journal Science.