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Why Does Hair on Moles Grow More Quickly?

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In medieval Europe and early colonial America, moles were seen as a sign of demonic possession (as was everything else). The ancient Greeks and Chinese, however, used the markings to try to decipher personality traits or destinies. In the age of modern pop culture, icons like Marilyn Monroe, Goldie Hawn, Cindy Crawford, and Madonna have turned moles into beauty marks to be desired and even emulated. But as anyone whose skin is accentuated by a mole can tell you, there is something particularly unique about them: They seem to grow hair at a faster rate than ordinary skin, and that hair often seems darker and coarser.

Why is this? Why do hairs burst forth from moles more quickly than they do from ordinary skin? Science actually doesn’t know.

“The short answer is that we’re not sure why the hair is coarser in moles or why it may seem to grow faster,” Lauren Ploch, a dermatologist based in Augusta, Georgia, tells mental_floss. “The development of moles is still a dermatologic mystery, as is the regulation of hair growth.”

When viewed under a microscope, nevus cells, a kind of melanocyte found in moles, don't invade the structure of hair follicles and seem to have no effect that would change hair appearance or growth, says Ploch.

Researchers do know that mole skin is different from other skin and develops as the result of a number of factors, including genetics, environment, hormones, and signaling proteins. Many of these elements (especially hormones and signaling proteins) also contribute to hair growth, says Ploch. So the presence of the mole and the underlining causes of it may tinker with the usual bodily factors regulating hair growth.

“I suspect that, while the mole itself may not have a direct role in creating a darker, coarser hair, the local milieu of signaling molecules and hormones in the skin that created the mole leads to a darker, coarser hair within the lesion,” she says.

She adds that moles often develop during puberty in response to androgen, the same steroid hormone that spurs facial and pubic hair growth, so moles and hair have a common stimulus. 

Science has yet to fully explain the behavior of moles, but at least we know more about them than we did during the middle ages.

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travel
Why You Should Never Take Your Shoes Off On an Airplane
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What should be worn during takeoff?

Tony Luna:

If you are a frequent flyer, you may often notice that some passengers like to kick off their shoes the moment they've settled down into their seats.

As an ex-flight attendant, I'm here to tell you that it is a dangerous thing to do. Why?

Besides stinking up the whole cabin, footwear is essential during an airplane emergency, even though it is not part of the flight safety information.

During an emergency, all sorts of debris and unpleasant ground surfaces will block your way toward the exit, as well as outside the aircraft. If your feet aren't properly covered, you'll have a hard time making your way to safety.

Imagine destroying your bare feet as you run down the aisle covered with broken glass, fires, and metal shards. Kind of like John McClane in Die Hard, but worse. Ouch!

Bruce Willis stars in 'Die Hard' (1988)
20th Century Fox Home Entertainment

A mere couple of seconds delay during an emergency evacuation can be a matter of life and death, especially in an enclosed environment. Not to mention the entire aircraft will likely be engulfed in panic and chaos.

So, the next time you go on a plane trip, please keep your shoes on during takeoff, even if it is uncomfortable.

You can slip on a pair of bathroom slippers if you really need to let your toes breathe. They're pretty useless in a real emergency evacuation, but at least they're better than going barefoot.

This post originally appeared on Quora. Click here to view.

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Big Questions
Where Should You Place the Apostrophe in President's Day?
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Happy Presidents’ Day! Or is it President’s Day? Or Presidents Day? What you call the national holiday depends on where you are, who you’re honoring, and how you think we’re celebrating.

Saying "President’s Day" infers that the day belongs to a singular president, such as George Washington or Abraham Lincoln, whose birthdays are the basis for the holiday. On the other hand, referring to it as "Presidents’ Day" means that the day belongs to all of the presidents—that it’s their day collectively. Finally, calling the day "Presidents Day"—plural with no apostrophe—would indicate that we’re honoring all POTUSes past and present (yes, even Andrew Johnson), but that no one president actually owns the day.

You would think that in the nearly 140 years since "Washington’s Birthday" was declared a holiday in 1879, someone would have officially declared a way to spell the day. But in fact, even the White House itself hasn’t chosen a single variation for its style guide. They spelled it “President’s Day” here and “Presidents’ Day” here.


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Maybe that indecision comes from the fact that Presidents Day isn’t even a federal holiday. The federal holiday is technically still called “Washington’s Birthday,” and states can choose to call it whatever they want. Some states, like Iowa, don’t officially acknowledge the day at all. And the location of the punctuation mark is a moot point when individual states choose to call it something else entirely, like “George Washington’s Birthday and Daisy Gatson Bates Day” in Arkansas, or “Birthdays of George Washington/Thomas Jefferson” in Alabama. (Alabama loves to split birthday celebrations, by the way; the third Monday in January celebrates both Martin Luther King, Jr., and Robert E. Lee.)

You can look to official grammar sources to declare the right way, but even they don’t agree. The AP Stylebook prefers “Presidents Day,” while Chicago Style uses “Presidents’ Day.”

The bottom line: There’s no rhyme or reason to any of it. Go with what feels right. And even then, if you’re in one of those states that has chosen to spell it “President’s Day”—Washington, for example—and you use one of the grammar book stylings instead, you’re still technically wrong.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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