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Has a U.S. River Run Backwards Before?

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The ongoing drought conditions wreaking havoc across large swaths of the country have driven the water in Lake Michigan an inch below its previous record low, and aren’t stopping. Last month, the U.S. Army Corps of Engineers announced that, if this continues and the lake water drops below the level of the Chicago River, the river could reverse course and begin flowing back towards its source. (Thankfully, there’s a series of locks separating the two, which will help prevent the less-than-clean river from flowing into the lake and the city’s source of drinking water.) Has an American river ever done an about-face like this before?

Right Back Where it Started From

Oh yeah. In fact, the Chicago has done it before. If the river does reverse course, it won’t be running backwards so much as running forwards again. 

When Europeans first settled in the Chicago area, the river drained into Lake Michigan, which was fine—except that settlers used the river to dump waste, and used the lake for drinking water. As the city grew, there were numerous outbreaks of typhoid and cholera because of contaminated drinking water, and something had to be done. 

In the late 1800s, the city decided to solve their problem with an ambitious engineering feat: They would reverse the flow of the river and send it away from the lake and towards the Mississippi River. The so-called “Chicago Diversion” worked: It not only diverted contaminated water away from the city’s drinking water, but also connected the Great Lakes and Mississippi River water systems and opened up the possibility of commercial travel and trade between them. 

It hasn't been just barges and haulers that could cross from one system to the other, though. Invasive Asian carp, introduced decades ago to southern fish farms as pond cleaners, have gradually made their way north, threatening native species and altering food webs as they go. With the fish nearing the Great Lakes, the idea of un-reversing (re-reversing?) the Chicago River has been kicked around, but now it looks like the river could take care of the problem itself. 

All Shook Up

The most famous of American Rivers, the mighty Mississippi, also might have gone backwards more than once. In 1811 and 1812, three earthquakes—the most powerful to ever hit the eastern U.S.—struck what was then a sparsely populated area of the Louisiana Territory. 

Eyewitness accounts from the quake read like Michael Bay scripts: The ground rippled and quivered; chasms opened up and swallowed livestock and wagons; sand and dirt exploded from the ground like volcanic eruptions and blotted out the sun; the Mississippi shook with such violence that the water ran backwards and boats were dragged upstream. 

One boatman, wanting to get away from the trees falling over on the river banks, put his boat out into the middle of the river and soon found, he claimed, that “the current changed, and the boat hurried up, for about the space of a minute, with the velocity of the swiftest horse,” fast enough that he had to hold on to his hat to keep it on his head. 

Gradually, the man said, the river returned to its normal course. Exactly how long that took is unclear, and various firsthand accounts have the river going backwards for anywhere from a few hours to a few days. Whether the river even reversed itself at all is questionable, and the United States Geological Survey says that ground uplifts and waves moving upstream may have just created the illusion that the water was moving backwards. 

What’s more certain is that the Mississippi reversed course for about 24 hours when Hurricane Isaac struck last year, and when Hurricane Katrina hit in 2005.

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Big Questions
Why Do Small Dogs Live Longer Than Large Dogs?
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Why do small dogs live longer than large dogs?

Adriana Heguy:

The issue of body size and lifespan is a fascinating topic in biology. It’s strange that across species, at least in mammals, large-bodied animals live longer than small-sized animals. For example, elephants live a lot longer than mice. The theory is that
bigger animals have slower metabolisms than small animals, and that faster metabolisms result in more accumulation of free radicals that damage tissue and DNA. But this doesn't always hold for all animals and the “rate of living” theory is not widely accepted. What we cannot clearly understand remains fascinating.

But now if we look at within a given species, lifespan and body size are inversely correlated. This is definitively the case for dogs and mice, and it has been proposed that this is the case for humans, too. Why would this be? A possible explanation is that larger dogs (or mice, or people) grow faster than their smaller counterparts because they reach a larger size in more or less the same time, and that faster growth could be correlated with higher cancer rates.

We do not have a clear understanding of why growing faster leads to accelerated aging. But it seems that it is an accelerated rate of aging, or senescence, that causes larger dogs to have shorter lifespans than little dogs.

The figure above is from Ageing: It’s a Dog’s Life. The data is from 32 breeds. Note that the inverse correlation is pretty good, however some large dog breeds, at around 40 to 50 kg (or about 88 to 110 pounds), live 12 or 13 years in average while some other dog breeds of equal body size live only eight or nine years on average. This is due to dogs being a special case, as they were artificially bred by humans to select for looks or behavior and not necessarily health, and that considerable inbreeding was necessary to produce “purebred” dogs. For example, boxers are big dogs, but their higher cancer rates may result in a shorter lifespan. However, the really giant breeds all consistently live eight to nine years on average. So there is something going on besides simple breeding quirks that led to bad genetics and ill health. Something more general.

A few years ago, a large study [PDF] was published using mortality data from thousands of dogs across 74 breeds, testing three hypotheses: Large dogs may die younger than small dogs because of (1) an earlier onset of senescence, (2) a higher minimum mortality hazard, or (3) an increased rate of aging. The conclusion from their study is that aging starts more or less at the same age in small and large breeds, but large breeds age faster. We do not have a clear understanding of the underlying mechanism for faster aging in dogs. It seems that when we selected for large body size, we selected for faster aging as well. But we do not know all the genetic components of this. We know that there are at least three genes that determine large body size in dogs: IRS4 and IGSF1, involved in thyroid hormone pathways which affect growth, and ACSL4, involved in muscle growth, and back fat thickness.

But how this accelerates aging is still speculation. More studies are needed, but dogs seem to be a great model to study the evolution of body size and its relationship to aging.

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

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Big Questions
Should You Keep Your Pets Indoors During the Solar Eclipse?
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By now, you probably know what you’ll be doing on August 21, when a total solar eclipse makes its way across the continental United States. You’ve had your safety glasses ready since January (and have confirmed that they’ll actually protect your retinas), you’ve picked out the perfect vantage point in your area for the best view, and you’ve memorized Nikon’s tips for how to take pictures of this rare celestial phenomenon. Still, it feels like you’re forgetting something … and it’s probably the thing that's been right under your nose, and sitting on your lap, the whole time: your pets.

Even if you’ve never witnessed a solar eclipse, you undoubtedly know that you’re never supposed to look directly at the sun during one. But what about your four-legged family members? Shouldn’t Fido be fitted with a pair of eclipse glasses before he heads out for his daily walk? Could Princess Kitty be in danger of having her peepers singed if she’s lounging on her favorite windowsill? While, like humans, looking directly at the sun during a solar eclipse does pose the potential of doing harm to a pet’s eyes, it’s unlikely that the thought would even occur to the little ball of fluff.

“It’s no different than any other day,” Angela Speck, co-chair of the AAS National Solar Eclipse Task Force, explained during a NASA briefing in June. “On a normal day, your pets don’t try to look at the sun and therefore don’t damage their eyes, so on this day they’re not going to do it either. It is not a concern, letting them outside. All that’s happened is we’ve blocked out the sun, it’s not more dangerous. So I think that people who have pets want to think about that. I’m not going to worry about my cat.”

Dr. Jessica Vogelsang, a veterinarian, author, and founder of pawcurious, echoed Speck’s statement, but allowed that there’s no such thing as being too cautious. “It’s hard for me to criticize such a well-meaning warning, because there’s really no harm in following the advice to keep pets inside during the eclipse,” Vogelsang told Snopes. “It’s better to be too cautious than not cautious enough. But in the interest of offering a realistic risk assessment, the likelihood of a pet ruining their eyes the same way a human would during an eclipse is much lower—not because the damage would be any less were they to stare at the sun, but because, from a behavior standpoint, dogs and cats just don’t have any interest in doing so. We tend to extrapolate a lot of things from people to pets that just doesn’t bear out, and this is one of them.

“I’ve seen lots of warnings from the astronomy community and the human medical community about the theoretical dangers of pets and eclipses, but I’m not sure if any of them really know animal behavior all that well," Vogelsang continued. "It’s not like there’s a big outcry from the wildlife community to go chase down coyotes and hawks and bears and give them goggles either. While we in the veterinary community absolutely appreciate people being concerned about their pets’ wellbeing, this is a non-issue for us.”

The bigger issue, according to several experts, would be with pets who are already sensitive to Mother Nature. "If you have the sort of pet that's normally sensitive to shifts in the weather, they might be disturbed by just the whole vibe because the temperature will drop and the sky will get dark,” Melanie Monteiro, a pet safety expert and author of The Safe-Dog Handbook: A Complete Guide to Protecting Your Pooch, Indoors and Out, told TODAY.

“If [your pets] have learned some association with it getting darker, they will show that behavior or at a minimum they get confused because the timeframe does not correspond,” Dr. Carlo Siracusa of Penn Vet Hospital told CBS Philly. “You might put the blinds down, but not exactly when the dark is coming but when it is still light.” 

While Monteiro again reasserts that, "Dogs and cats don't normally look up into the sun, so you don't need to get any special eye protection for your pets,” she says that it’s never a bad idea to take some extra precautions. So if you’re headed out to an eclipse viewing party, why not do your pets a favor and leave them at home. They won’t even know what they’re missing.

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