Ogier Ghiselin de Busbecq – Scientist of the Day

Ogier Ghiselin de Busbecq, a Flemish botanist and
diplomat, died Oct. 28, 1592, at age 70.

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The giant sequoias in the Sierra Nevada are one of America’s treasures, but for the first time in Sequoia National Park’s history, the trees are showing visible signs of exhaustion due to the drought.

On a hike last summer, a scientist noticed that the leaves of the giant sequoias were browning and more sparse than usual. This finding got ecologists thinking: Did the drought cause this?

“We’re just trying to get a better understanding of how giant sequoia trees respond to severe drought. We have very little understanding of … how severe of a drought it takes to kill a giant sequoia tree,” says Anthony Ambrose, a tree biologist at University of California, Berkeley.

Some of the sequoias in the park are over 3,000 years old and have faced many droughts in their lifespans. But perhaps this drought is too much for them.

To Measure Drought’s Reach, Researchers Scale The Mighty Sequoia

Photo credit: Ezra David Romero/Valley Public Radio


Why Do People ‘Twitch’ When Falling Asleep?

A hypnagogic jerk is an involuntary muscle spasm that occurs as a person is drifting off to sleep.

The phenomenon is so named in reference to the hypnogogic state — the transitional period between wakefulness and sleep. Hypnagogic jerks are also commonly known as hypnic jerks or sleep starts.

The muscle spasms may occur spontaneously or may be induced by sound, light or other external stimuli. Some people report hypnagogic jerks accompanied by hallucinations, dreams, the sensation of falling, or bright lights or loud noises coming from inside the head.

Sleep starts are quite common, with some research suggesting that 60 to 70 percent of people experience them. Many individuals may be visited by nightly hypnic jerks without even knowing it, as the twitches often go unremembered, particularly if they don’t cause a person to wake up.

Some scientists believe certain factors, such as stress, anxiety, fatigue, caffeine and sleep deprivation, may increase the frequency or severity of hypnagogic jerks, but conclusive research is lacking on the subject.

Researchers are also unsure why hypnic jerks occur, but a few theories exist.

One hypothesis says that

the spasms are an ancient primate reflex to the relaxation of muscles during the onset of sleep — the brain essentially misinterprets the relaxation as a sign that the sleeping primate is falling out of a tree, and causes the muscles to quickly react.

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