The smell of time passing

We once owned a very peculiar border collie named Doolin.  Although from what I've heard, saying "very peculiar" in the same breath as "border collie" is kind of redundant.  The breed has a reputation for being extremely intelligent, hyperactive, job-oriented, and more than a little neurotic, and Doolin fit the bill in all respects.

As far as the "intelligent" part, she's the dog who learned to open the slide bolts on our fence by watching us do it only two or three times.  I wouldn't have believed it unless I'd seen it with my own eyes.  She also took her job very seriously, and by "job" I mean "life."  She had a passion for catching frisbees, but I always got the impression that it wasn't because it was fun.  It was because the Russian judge had only given her a 9.4 on the previous catch and she was determined to improve her score.

There were ways in which her intelligence was almost eerie at times.  I was away from home one time and called Carol to say hi, and apparently Doolin looked at her with question marks in her eyes.  Carol said, "Doolin, it's Daddy!"  Doolin responded by becoming extremely excited and running around the house looking in all of the likely spots -- my office, the recliner, the workshop -- as well as some somewhat less likely places like under the bed.  When the search was unsuccessful, apparently she seemed extremely worried for the rest of the evening.

Not that this was all that different from her usual expression.

One thing that always puzzled us, though, was her ability to sense when we were about to get home.  Doolin routinely went to the door and stood there on guard before Carol's car pulled into the driveway.  She did the same thing, I heard, when I was about to arrive.  In each case, there was no obvious cue that she could have relied on; we live on a fairly well-traveled stretch of rural highway and even if she heard our cars in the distance, I can't imagine they sound that different from any of the other hundreds of cars that pass by daily.  And my arrival time, especially, varied considerably from day to day, because of after-school commitments.  How, then, did she figure out we were about to get home -- or was it just dart-thrower's bias again, and we were noticing the times she got it right and ignoring all the times she didn't?

According to Alexandra Horowitz, a professor of psychology at Barnard University, there's actually something to this observation.  There are hundreds of anecdotal accounts of the same kind of behavior, enough that (although there hasn't been much in the way of a systematic study) there's almost certainly a reason behind it other than chance.  Horowitz considered the well-documented ability of dogs to follow a scent trail the right direction by sensing where the signal was weakest -- presumably the oldest part of the trail -- and heading toward where it was stronger.  The difference in intensity is minuscule, especially given that to go the right direction the dog can't directly compare the scent right here to the scent a half a kilometer away, but has to compare the scent here to the scent a couple of meters away.

What Horowitz wondered is if dogs are using scent intensity as a kind of clock -- the diminishment of a person's scent signal after they leave the house gives the dog a way of knowing how much time has elapsed.  This makes more sense than any other explanation I've heard, which include (no lie) that dogs are psychic and are telepathically sensing your approach.  Biological clocks of all kinds are only now being investigated and understood, including how they are entrained -- how the internal state is aligned to external cues.  (The most obvious examples of entrainment are the alignment of our sleep cycle to light/dark fluctuations, and seasonal behaviors in other animals like hibernation and migration in response to cues like decreasing day length.)

So it's possible that dogs are entraining this bit of their behavior using their phenomenally sensitive noses.  It'll be interesting to see what Horowitz does with her hypothesis; it's certainly worth testing.  Now, I need to wrap this up because Guinness's biological clock just went off and told him it was time to play ball.  Of course, that happens about fifty times a day, so there may not be anything particularly surprising there.

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Forever young

At 61 I'm reaching the age where I can't deny that I'm not young any more.  By and large, though, I've been lucky.  I now need bifocals -- more to read than to do anything else, but I wear them all the time because if I don't I'll lose them, yet another fun feature of aging.  I have mild high blood pressure (controlled by medication).  A few gray hairs and laugh lines.

But overall, I'm pretty fortunate.  It's a curious thing, though, why people seem to age at different rates, and (in the broader sense) why some species age faster.  It's a current hot topic in research; why (for example) do mice mostly age out at three or four years, dogs at age thirteen or fourteen (lower for some large breeds), cats at seventeen or so, horses by age thirty, and so on?  Despite improvement in human life expectancy because of better prevention and treatment of disease, scientists haven't been able to do much about aging itself; if you are diagnosed with heart disease, you'd have a better chance of surviving now than you would have a hundred years ago, but all of the attendant features of old age proceed at the same rate they always have.

One of the biggest mysteries about aging is why some animals seem to be resistant to it.  I'm not just talking about life expectancy; even though mice and humans have vastly different life spans, toward the end of their lives they're prone to the same things -- cardiac and circulatory problems, arthritis, eyesight and hearing loss, dementia.  It's just that with mice, that whole cycle is compressed by a factor of twenty-five.  More puzzling are the handful of animals that don't seem to age at all, at least not in the conventional sense; for example, there's a hydrozoan jellyfish, Turritopsis dohrnii, that cheats death by something almost like a Doctor Who-style regeneration; it transforms itself, down to the cellular level, to the youthful (polyp) stage, then starts over from there, rendering it effectively immortal if it doesn't die from other causes.

Jellyfish are, of course, a long way from humans evolutionarily (and therefore genetically).  Closer to us are the bizarre naked mole-rats (Heterocephauls glaber) of the deserts of Ethiopia and Somalia.  They've been the focus of a lot of study -- Chris Faulkes, of Queen Mary University of London, has been looking at their weird, almost ant-colony-style social structure, and says, "They just draw you in; they’re obviously really, really cute," which I find kind of mystifying, because to me they look like a penis with teeth.

But eye of the beholder, and all that sorta stuff.

What's weirdest about these odd rodents, though, is that unlike their more familiar cousins, they have life spans of forty or more years.  But this isn't a case of simply taking the years of life, with all of their attendant ills at the end, and adjusting it accordingly; naked mole-rats simply don't seem to get all the age-related disorders.  Cardiac and circulatory problems, arthritis, type-2 diabetes, and so on, just don't afflict them.  What exactly they do die of is still a bit of a mystery, because they seem to be just as vigorous at age 35 as they were at age 5.  "Naked mole-rats are a model of healthy aging," said Vera Gorbunova, of the University of Rochester, who has been studying how they accomplish this.

She and her colleagues have uncovered some unexpected results.  What's oddest is that their genetic biological clocks -- something that all mammals have, which are indicators of age regardless of overall health -- seem to keep track perfectly well.  It might make sense to surmise that a species who cheats aging so adroitly might be doing it by virtue of a broken biological clock, but that's not what's going on here.  They have seven molecular clocks that work as good indicators of age, and in fact, two of them are also found in humans (and work the same way).  An alternative theory -- one that's being researched -- is that they are better at protecting their epigenomes (the record of alterations made to an individual's genome during its lifetime), or at fixing damage to the DNA, but both are at this point only hypotheses.

Naturally, what people are wondering is whether any discoveries of how exactly the naked mole-rats are doing this could be applied to humans.  On the one hand, increasing our life spans dramatically would do no favors for our already overcrowded Earth; but I have to say, if I could improve my likelihood of healthy aging, I'd be the first in line.  I'm not really afraid of dying, but I am afraid of debility -- I'm one of those people who loathes having to be dependent on others for my care, so some of the degenerative diseases of old age absolutely scare the shit out of me.

We're a long way from that, though, probably long enough that it won't do me much good.  So I guess I'll have to continue relying on my good diet, exercise, and a family history of long-lived people to keep me going.  Even if we find out what the naked mole-rats are doing, transplanting that into a human is going to be a considerable, if not insurmountable, challenge.

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It's obvious to regular readers of Skeptophilia that I'm fascinated with geology and paleontology.  That's why this week's book-of-the-week is brand new: Thomas Halliday's Otherlands: A Journey Through Extinct Worlds.

Halliday takes us to sixteen different bygone worlds -- each one represented by a fossil site, from our ancestral australopithecenes in what is now Tanzania to the Precambrian Ediacaran seas, filled with animals that are nothing short of bizarre.  (One, in fact, is so weird-looking it was christened Hallucigenia.)  Halliday doesn't just tell us about the fossils, though; he recreates in words what the place would have looked like back when those animals and plants were alive, giving a rich perspective on just how much the Earth has changed over its history -- and how fragile the web of life is.

It's a beautiful and eye-opening book -- if you love thinking about prehistory, you need a copy of Otherlands.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Siesta time

I'm a morning person.

I know this is pretty unusual.  I also know from first-hand experience that night owls tend to hate us morning people, who are up with the sun and at least reasonably coherent by six a.m., if not always showered and fully dressed.  (Hell, I'm retired.  Fully dressed sometimes doesn't happen at all, especially when the weather is warm.)

The result, though, is that I fade out pretty early in the evening.  I'm one of those people who, when invited to a party, seriously consider saying no if the start time is after seven in the evening.  By eight I want to be reading a book, and the times I'm still awake at ten are few and far between.

But the lowest time for me, energy-wise, is right after lunch.  Even when I get adequate sleep, I go through a serious slump in the early afternoon, even if I was chipper beforehand.  (Okay, given my personality, I'm never really chipper.  I also don't do "perky" or "bubbly."  So think about it as "chipper as compared to my baseline demeanor.")

Turns out, I'm not alone in finding the early afternoon a tough time to be productive, or even to stay awake.  As I learned from a paper in The Journal of Neuroscience, the problem is a fluctuation in the brain's reward circuit -- it, like many other human behaviors, is on a circadian rhythm that affects its function in a regular and predictable fashion.

The problem is a misalignment of the putamen (part of the brain's reward circuit) and the suprachiasmatic nucleus, which acts as a biological clock.  The putamen is most active when you receive a reward you weren't expecting, and least active when you expect a reward and don't get one.  The cycling of the suprachiasmatic nucleus stimulates the putamen to expect a reward after lunch, and then when it doesn't come -- one in the afternoon is nowhere near quitting time or happy hour, and most people's schedules don't accommodate an early afternoon nap -- the expected payoff doesn't happen.

The result: sad putamen.  Drop in motivation levels.

"The data suggest that the brain’s reward centres might be primed to expect rewards in the early afternoon, and be ‘surprised’ when they appear at the start and end of the day," said neuroscientist Jamie Byrne of Swinburne University.  "[The] brain is ‘expecting’ rewards at some times of day more than others, because it is adaptively primed by the body clock."

Me, I wonder why this priming happens at all.  What sort of reward did we receive in the early afternoon in our evolutionary history that led to this response becoming so common?  Honestly, I wonder if it was napping; an afternoon nap has been found not only to improve cognitive function, but (contrary to popular opinion) doesn't generally interfere with sleeping at night.  Having evolved on the African savanna, where the early afternoon can be miserably hot, it could be that we're built to snooze in the shade after lunch, and now that most of us are on an eight-to-five work schedule, we can't get away with it any more.  But the circadian rhythm we evolved is still there, and our energy levels plummet after lunch.

[Image licensed under the Creative Commons Jamain, Sleeping man J1, CC BY-SA 3.0]

It reminds me of the three weeks I spent in Spain and Portugal a few years ago.  I was astonished at first by the fact that no one ate dinner -- even considered eating dinner -- until nine in the evening.  (On one of our first days there, we went to a restaurant at about eight, and asked the waiter if we could be seated at a table.  His response was, "Why?"  I think he was genuinely puzzled as to why anyone might want dinner at such a ridiculously early hour.)  But once we got the hang of it -- a big lunch with a bottle of fine red wine, then a three-hour siesta during the hottest part of the day, when businesses close their doors so there's nothing much to do but sleep anyhow -- even I was able to stay up late with no problem.

All in all, a very pleasant lifestyle, I thought.

So we now know there is a neurological reason for the early-afternoon energy slump.  Kind of a fascinating thing how much we're at the mercy of our biological clock.  But anyhow, I better get busy and get some chores done.  Time's a-wasting, and I'm guessing by lunchtime I won't be feeling like doing much but hitting the hammock and conking out for a while.

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This week's Skeptophilia book recommendation of the week is pure fun, and a great gift for any of your friends who are cryptid fanciers: Graham Roumieu's hilarious Me Write Book: It Bigfoot Memoir.

In this short but hysterically funny book, we find out from the Big Guy's own mouth how hard it is to have the reputation for being huge, hairy, and bad-smelling.  Okay, even he admits he doesn't smell great, but it's not his fault, as showers aren't common out in the wilderness.  And think about the effect this has on his self-image, not to mention his success rate of advertising in the "Personals" section of the newspaper.

So read this first-person account of the struggles of this hirsute Everyman, and maybe even next time you're out hiking, bring along a little something for our australopithecene distant cousin.

He's very fond of peach schnapps.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Timing out

One of my ongoing frustrations when I was a teacher was the failure of the educational community to use the latest scientific research to guide our approach to pedagogy.

Of course, I shouldn't be surprised.  We here in the United States have made a national pastime out of ignoring scientific research -- climate change and the safety/efficacy of vaccinations being two of the most obvious examples.  Still, it was maddening to see things like high school students struggling in Spanish I when if we put our resources into bilingual education in preschool, kids would learn a second language as easily as they did their first.

And research into the window of opportunity for language learning has been around for thirty years.

Another example was the subject of a paper this week in Nature: Human Behavior.  In "Interplay of Chronotype and School Timing Predicts School Performance," by Andrea P. Goldin, Mariano Sigman, Gisela Braier, Diego A. Golombek, and María J. Leone, of Universidad Torcuato di Tella (Buenos Aires, Argentina), we find out that people tend to have chronotypes -- natural biological clocks that time our highest and lowest alertness -- and that when schools run counter to a student's chronotype, it drastically impacts performance.

[Image licensed under the Creative Commons Robbert van der Steeg, Eternal clock, CC BY-SA 2.0]

I know this from my own experience.  I'm naturally a lark -- up with the sun.  Often earlier, even.  My morning classes in college (and teaching morning classes during my career as an educator) were easy for me.  But I have a slow fade after lunch time -- and by a time that for many people is Evening Party Time, I'm ready to be curled up in bed with a good book.

I literally haven't slept past eight o'clock in maybe twenty years.  And staying up past ten PM?

Not if you want me to be halfway coherent.

But I was painfully aware that a lot of students seemed to be on the opposite schedule.  Trying to get them to learn biology first thing in the morning (hell, trying to get them to stay awake) was an ongoing challenge.  And I can't tell you the number of students who told me that they stay up regularly till three AM -- not because of homework or social media (although those did tend to fill the wakeful hours), but because they were wide awake and going to bed earlier than that would be an exercise in frustration.

So it's a double whammy.  We take kids who are naturally night owls, make them get up early (depriving them of much-needed sleep), and then expect them to perform optimally on intellectual tasks.

Goldin et al. pull no punches about this:

Most adolescents exhibit very late chronotypes and attend school early in the morning, a misalignment that can affect their health and psychological well-being.  Here we examine how the interaction between the chronotype and school timing of an individual influences academic performance, studying a unique sample of 753 Argentinian students who were randomly assigned to start school in the morning (07:45), afternoon (12:40) or evening (17:20).  Although chronotypes tend to align partially with class time, this effect is insufficient to fully account for the differences with school start time.  We show that (1) for morning-attending students, early chronotypes perform better than late chronotypes in all school subjects, an effect that is largest for maths; (2) this effect vanishes for students who attend school in the afternoon; and (3) late chronotypes benefit from evening classes.  Together, these results demonstrate that academic performance is improved when school times are better aligned with the biological rhythms of adolescents.

And I strongly suspect that the effect this research will have on the educational community is... nada.

My wife has a poster in her office showing a dude hauling ass in the annual Pamplona Running of the Bulls, a thousand pounds of snorting animal right behind him.  The caption is: "TRADITION: Just because we've always done it this way doesn't mean it's not a really, really stupid idea."

To which the educational establishment of the United States tends to say, "Oh, well, too bad."

The most frustrating thing is that apparently it doesn't take much of a change to make a difference.  Bumping school start times ahead by an hour -- so from eight to nine AM, in the school district where I taught -- was shown to improve daytime alertness and the quality/length of sleep in adolescents in a study done six years ago.  It still wouldn't be optimal for students who are really night owls, but at this point any gain at all would be an improvement.

But given how most schools have responded to thirty-year-old research on language learning, the Goldin et al. study will probably be filed away with lots of other research, in a folder labeled, "Well, It Would Be Nice, But..."

Along with recommendations to our federal government for halting climate change and mandatory vaccination programs.  Seems like it's an uphill battle for most things these days.

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This week's Skeptophilia book of the week is a dark one, but absolutely gripping: the brilliant novelist Haruki Murakami's Underground: The Tokyo Gas Attack and the Japanese Psyche.

Most of you probably know about the sarin attack in the subways of Tokyo in 1995, perpetrated by members of the Aum Shinrikyo cult under the leadership of Shoko Asahara.  Asahara, acting through five Aum members, set off nerve gas containers during rush hour, killing fifty people outright and injuring over a thousand others.  All six of them were hanged in 2018 for the crimes, along with a seventh who acted as a getaway driver.

Murakami does an amazing job in recounting the events leading up to the attack, and getting into the psyches of the perpetrators.  Amazingly, most of them were from completely ordinary backgrounds and had no criminal records at all, nor any other signs of the horrors they had planned.  Murakami interviewed commuters who were injured by the poison and also a number of first responders, and draws a grim but fascinating picture of one of the darkest days in Japanese history.

You won't be able to put it down.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

The smell of time passing

We once owned a very peculiar border collie named Doolin.  Although from what I've heard, saying "very peculiar" in the same breath as "border collie" is kind of redundant.  The breed has a reputation for being extremely intelligent, hyperactive, job-oriented, and more than a little neurotic, and Doolin fit the bill in all respects.

As far as the "intelligent" part, she's the dog who learned to open the slide bolts on our fence by watching us do it only two or three times.  I wouldn't have believed it unless I'd seen it with my own eyes.  She also took her job very seriously, and by "job" I mean "life."  She had a passion for catching frisbees, but I always got the impression that it wasn't because it was fun.  It was because the Russian judge had only given her a 9.4 on the previous catch and she was determined to improve her score.

There were ways in which her intelligence was almost eerie at times.  I was away from home one time and called Carol to say hi, and apparently Doolin looked at her with question marks in her eyes.  Carol said, "Doolin, it's Daddy!"  Doolin responded by becoming extremely excited and running around the house looking in all of the likely spots -- my office, the recliner, the workshop -- as well as some somewhat less likely places like under the bed.  When the search was unsuccessful, apparently she seemed extremely worried for the rest of the evening.

Not that this was all that different from her usual expression.

One thing that always puzzled us, though, was her ability to sense when we were about to get home.  Doolin would routinely go to the door and stand there on guard before Carol's car pulled into the driveway.  She did the same thing, I heard, when I was about to arrive.  In each case, there was no obvious cue that she could have relied on; we live on a fairly well-traveled stretch of rural highway and even if she heard our cars in the distance, I can't imagine they sound that different from any of the other hundreds of cars that pass by daily.  And my arrival time, especially, varied considerably from day to day, because of after-school commitments.  How, then, did she figure out we were about to get home -- or was it just dart-thrower's bias again, and we were noticing the times she got it right and ignoring all the times she didn't?

According to Alexandra Horowitz, a professor of psychology at Barnard University, there's actually something to this observation.  There are hundreds of anecdotal accounts of the same kind of behavior, enough that (although there hasn't been much in the way of a systematic study) there's almost certainly a reason behind it other than chance.  Horowitz considered the well-documented ability of dogs to follow a scent trail the right direction by sensing where the signal was weakest -- presumably the oldest part of the trail -- and heading toward where it was stronger.  The difference in intensity is minuscule, especially given that to go the right direction the dog can't directly compare the scent right here to the scent a half a kilometer away, but has to compare the scent here to the scent a couple of meters away.

What Horowitz wondered is if dogs are using scent intensity as a kind of clock -- the diminishment of a person's scent signal after they leave the house gives the dog a way of knowing how much time has elapsed.  This makes more sense than any other explanation I've heard, which include (no lie) that dogs are psychic and are telepathically sensing your approach.  Biological clocks of all kinds are only now being investigated and understood, including how they are entrained -- how the internal state is aligned to external cues.  (The most obvious examples of entrainment are the alignment of our sleep cycle to light/dark fluctuations, and seasonal behaviors in other animals like hibernation and migration in response to cues like decreasing day length.)

So it's possible that dogs are entraining this bit of their behavior using their phenomenally sensitive noses.  It'll be interesting to see what Horowitz does with her hypothesis; it's certainly worth testing.  Now, I need to wrap this up because Guinness's biological clock just went off and told him it was time to play ball.  Of course, that happens about fifty times a day, so there may not be anything particularly surprising there.

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This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

[Note: if you purchase this book from the image/link below, part of the proceeds goes to support Skeptophilia!]

A consummation devoutly to be wished

When I was in college, I had an eight a.m. calculus class with a woman who used to drag herself in, large coffee in her hand, looking like death warmed over.  The first time this happened, I thought she'd just pulled an all-nighter either studying or partying -- both common occurrences in college -- but then I noticed it was day after day.  The poor woman never looked wide awake, and always seemed just this side of miserable.

Finally, being the subtle and compassionate person you all know me to be, I said to her, "What the hell is wrong with you?", or words to that effect.

She explained to me that she had serious sleep issues.  She'd get back to her dorm from her last class in the afternoon, still feeling exhausted, but then she'd get a second wind in the early evening.  Come a reasonable bedtime -- say, ten-thirty or eleven -- she was wide awake.

"I don't even bother going to bed," she told me.  "I tried it, more than once, and lay there for hours staring at the ceiling.  Now I just get up and try to be productive."

Until about four-thirty or five in the morning, when she'd finally feel tired.  Then she'd go to sleep, and her alarm would go off at six, and she'd start the whole cycle again -- with about an hour's worth of sleep.

I didn't find out until much later that what she was suffering from has a name; circadian dysrhythmia.  Basically, it's when your biological clock is completely out of sync with the rest of the world.  It's a little like a permanent case of jet lag.  And sadly, even now, forty years later, it's still remarkably resistant to treatment.

It's been the conventional wisdom for some time that circadian rhythms are mediated through a part of the brain called the hypothalamus.  And this is clearly part of the answer; sleepiness is correlated with increased activity in the anterior part of the region, and an increase in the hypothalamic production of the neurotransmitter gamma amino-butyric acid (GABA), which has an inhibitory effect on neural excitation.

[Image is licensed under the Creative Commons Jamain, Sleeping man J1, CC BY-SA 3.0]

But two new papers, published simultaneously last week in the journal Cell, have shown us that things may not be that simple.  (Are they ever?)  Both studies were done at the University of California - Irvine, and have shown that the network of internal clocks that regulates our metabolism, activity, alertness, and other cyclic behaviors are not limited to the brain -- that other parts of the body also have significant contributions to modulating our daily cycles.

In the first, titled, "BMAL1-Driven Tissue Clocks Respond Independently to Light to Maintain Homeostasis," researchers found that a chemically-driven clock exists... in our skin cells.  The authors write:

Circadian rhythms control organismal physiology throughout the day.  At the cellular level, clock regulation is established by a self-sustained Bmal1-dependent transcriptional oscillator network [a cyclic rise and fall of gene activity associated with light levels].  However, it is still unclear how different tissues achieve a synchronized rhythmic physiology.  That is, do they respond independently to environmental signals, or require interactions with each other to do so?  We show that unexpectedly, light synchronizes the Bmal1-dependent circadian machinery in single tissues in the absence of Bmal1 in all other tissues.  Strikingly, light-driven tissue autonomous clocks occur without rhythmic feeding behavior and are lost in constant darkness.

Maybe not so shocking, given that our skin is at least partly exposed to the light.  What is more surprising is the second paper, which found that a light-dependent circadian rhythm takes place in our livers:

Mammals rely on a network of circadian clocks to control daily systemic metabolism and physiology.  The central pacemaker in the suprachiasmatic nucleus (SCN) is considered hierarchically dominant over peripheral clocks, whose degree of independence, or tissue-level autonomy, has never been ascertained in vivo.  Using arrhythmic Bmal1-null mice, we generated animals with reconstituted circadian expression of BMAL1 exclusively in the liver (Liver-RE)...  [R]hythmic clock gene expression is lost in Liver-RE mice under constant darkness.  Hence, full circadian function in the liver depends on signals emanating from other clocks, and light contributes to tissue-autonomous clock function.

"The results were quite surprising," said Paolo Sassone-Corsi, who co-authored both studies.  "No one realized that the liver or skin could be so directly affected by light...  The future implications of our findings are vast.  With these mice, we can now begin deciphering the metabolic pathways that control our circadian rhythms, aging processes and general well-being."

It's undeniable that sleep plays a central role in both mental and physical health, and that the vast majority of us don't get sufficient sleep either in quantity or quality.  The more scientists find out about how our sleep cycles and other circadian rhythms are modulated, the greater the likelihood there'll be a treatment for people like my long-ago college acquaintance -- and even for simple insomniacs like myself.

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As will be obvious to any long-time readers of Skeptophilia, I have a positive fascination with things that are big and scary and can kill you.

It's why I tell my students, in complete seriousness, if I hadn't become a teacher I'd have been a tornado chaser.  There's something awe-inspiring about the sheer magnitude of destruction they're capable of.  Likewise earthquakes, hurricanes, wildfires...

But as sheer destructive power goes, there's nothing like the ones that are produced off-Earth.  These are the subject of Phil Plait's brilliant, funny, and highly entertaining Death From the Skies.  Plait is best known for his wonderful blog Bad Astronomy, which simultaneously skewers pseudoscience and teaches us about all sorts of fascinating stellar phenomena.  Here, he gives us the scoop on all the dangerous ones -- supernovas, asteroid collisions, gamma-ray bursters, Wolf-Rayet stars, black holes, you name it.  So if you have a morbid fascination with all the ways the universe is trying to kill you, presented in such a way that you'll be laughing as much as shivering, check out Plait's book.

[Note:  If you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]