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How whales got their teeth

A multidisciplinary team of researchers has married together the fossil record and the embryonic development process to investigate how the whale got its teeth. Not all whales have teeth, but those that do, such as killer whales, have rows of simple peg like teeth, each one looking the same as the next. Whales use this spiked row of teeth to grab prey, but unlike other mammals, whales do not chew.

In a new study, Brooke Armfield and colleagues investigated the developmental processes that cause the teeth of dolphins, whales' smaller cousins, to be different, and tracked the evolutionary progression of their unique dentition across the fossil record.  Whales evolved from land mammals and so Armfield and co-workers first went to the fossil record to trace when and how whales evolved their simple teeth. The fossil record shows that, 48 million years ago, whales had the same four kinds of teeth just like most other mammals.

Most mammals have four kinds of teeth, each shaped for specific tasks. In most mammals there are wedge-shaped incisors, a pointy canine, and premolars and molars with bumps and valleys that fit together like a mortar and pestle when you chew.  Gradually, the teeth of whales became simpler and acquired their characteristic peg-like appearance around 30 million years ago, well after the time that they had acquired an array of adaptations for living in the water.

“The simple shift in the location of proteins that influence tooth shape found in whales may help us to better understand how mammals evolved their complex tooth in the first place,” said Armfield.

Star with cool atmospheric layer identified

ESA’s Herschel space observatory has detected a cool layer in the atmosphere of Alpha Centauri A, the first time this has been seen in a star beyond our own sun. The finding is not only important for understanding the sun’s activity, but could also help in the quest to discover proto-planetary systems around other stars.

The sun’s nearest neighbours are the three stars of the Alpha Centauri system.
The faint red dwarf, Proxima Centauri, is nearest at just 4.24 light-years, with the tight double star, Alpha Centauri AB, slightly further away at 4.37 light-years. Alpha Centauri B has recently been in the news after the discovery of an earth-mass planet in orbit around it.

But Alpha Centauri A is also very important to astronomers: almost a twin to the sun in mass, temperature, chemical composition and age, it provides an ideal natural laboratory to compare other characteristics of the two stars.  One of the great curiosities in solar science is that the sun’s wispy outer atmosphere – the corona – is heated to millions of degrees while the visible surface of the sun is ‘only’ about 6,000ºC. Even stranger, there is a temperature minimum of about 4000ºC between the two layers, just a few hundred kilometres above the visible surface in the part of sun’s atmosphere called the chromosphere.

“The study of these structures has been limited to the sun until now, but we clearly see the signature of a similar temperature inversion layer at Alpha Centauri A,” Rene Liseau of the Onsala Space Observatory, Sweden, and lead author of the paper presenting the results said.

Acupuncture may help relieve seasonal allergies

Acupuncture may help relieve seasonal allergy symptoms in some people with runny noses and watery eyes, according to a recent study out of Germany - but the effect seems to be small.

Researchers studied the effect of acupuncture over eight weeks and reported a decrease in allergy symptoms, according to Fox News.

The exact mechanism is not known or even clear; however, the researchers believe that it may be due to an effect on the immune system.

In some cases, it appeared a reduction in the amount of allergy medications might be possible, they said.

They suggested that acupuncture might be helpful when combined with Western treatments.

But they said that patients should discuss with their allergist before changing or stopping any medications.

The study was published in the Annals of Internal Medicine.

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