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April 03, 2013

What Makes Rain Smell So Good?

What Makes Rain Smell So Good? | Surprising Science
Back in 1964, a pair of Australian scientists (Isabel Joy Bear and R. G. Thomas) began the scientific study of rain’s aroma in earnest with an article in Nature titled “Nature of Agrillaceous Odor.” In it, they coined the term petrichor to help explain the phenomenon, combining a pair of Greek roots: petra (stone) and ichor (the blood of gods in ancient myth). In that study and subsequent research, they determined that one of the main causes of this distinctive smell is a blend of oils secreted by some plants during arid periods. When a rainstorm comes after a drought, compounds from the oils—which accumulate over time in dry rocks and soil—are mixed and released into the air. The duo also observed that the oils inhibit seed germination, and speculated that plants produce them to limit competition for scarce water supplies during dry times. These airborne oils combine with other compounds to produce the smell. In moist, forested areas in particular, a common substance is geosmin, a chemical produced by a soil-dwelling bacteria known as actinomycetes. The bacteria secrete the compound when they produce spores, then the force of rain landing on the ground sends these spores up into the air, and the moist air conveys the chemical into our noses. “It’s a very pleasant aroma, sort of a musky smell,” soil specialist Bill Ypsilantis told NPR during an interview on the topic. “You’ll also smell that when you are in your garden and you’re turning over your soil.”

April 02, 2013

Algal blooms may become the norm for Lake Erie

Blame agricultural run-off. Algal Blooms May Become the Norm in Lake Erie: Scientific American
The Native Indians of Ohio called the area that is now northwestern Ohio and southeastern Michigan the "Great Black Swamp" -- a land of marshy wetlands. The early pioneers were able to dredge the land and turn it into the rich, productive region it is today. Corn and soybeans dominate in the region, and high prices for both commodities in recent years have encouraged farmers to keep sowing more rows, said Joe Logan, director of agricultural programs for the Ohio Environmental Council. "There is a compelling economic interest for farmers to maximize productivity," Logan said. Below the surface of the fields lie networks of perforated tubing, which pull excess water from the soil and send it to the lake, rich in phosphorus, Logan said. Before the 1970s, phosphorus runoff to Lake Erie's western basin was mostly due to municipal sewers and industry, said David Baker, who founded the National Center for Water Quality Research at Heidelberg University in Tiffin, Ohio, in 1969. By 1980, the phosphorus from agricultural runoff was almost twice the amount from municipal sources, he said. The patterns also changed. While municipal sources of pollution tend to be consistent throughout the year, agricultural runoff increases tremendously in the spring with the swelling of rivers and streams from the rain.

The Myers-Briggs test has no credibility, why is it so popular?

When I worked at Lexis-Nexis we had to take this silly personality test every year as part of a team-building exercise. It never felt accurate, more like getting everyone into a room and doing the world's most boring Cosmo dating quiz. Nothing Personal: The questionable Myers-Briggs test | Science | guardian.co.uk
I was recently reviewing some psychological lectures for my real job. One of these was on personality tests. The speaker mentioned the Myers-Briggs test, explaining that, while well known (I personally know it from a Dilbert cartoon) the Myers-Briggs test isn't recognised as being scientifically valid so is largely ignored by the field of psychology. I tweeted this fact, thinking it would be of passing interest to a few people. I was unprepared for the intensity of the replies I got. I learned several things that day. 1. The Myers-Briggs Type Indicator (MBTI) is used by countless organisations and industries, although one of the few areas that doesn't use it is psychology, which says a lot. 2. Many people who have encountered the MBTI in the workplace really don't have a lot of positive things to say about it. 3. For some organisations, use of the MBTI seemingly crosses the line into full-blown ideology. So how did something that apparently lacks scientific credibility become such a popular and accepted tool? The MBTI was developed during World War 2 by Myers and Briggs (obviously), two housewives who developed a keen interest in the works of Carl Jung. They developed the MBTI based on Jung's theories, with the intention of producing a useful test that would allow women entering the workforce to be assigned jobs that would be best suited to their personalities. . . .