The gradual yellowing of the lens and the narrowing of the pupil that occur with age disturb the body’s circadian rhythm, contributing to a range of health problems, these studies suggest. As the eyes age, less and less sunlight gets through the lens to reach key cells in the retina that regulate the body’s circadian rhythm, its internal clock.

“We believe the effect is huge and that it’s just beginning to be recognized as a problem,” said Dr. Patricia Turner, an ophthalmologist in Leawood, Kan., who with her husband, Dr. Martin Mainster, a professor of ophthalmology at the University of Kansas Medical School, has written extensively about the effects of the aging eye on health.

Circadian rhythms are the cyclical hormonal and physiological processes that rally the body in the morning to tackle the day’s demands and slow it down at night, allowing the body to rest and repair. This internal clock relies on light to function properly, and studies have found that people whose circadian rhythms are out of sync, like shift workers, are at greater risk for a number of ailments, including insomnia, heart disease and cancer.

“Evolution has built this beautiful timekeeping mechanism, but the clock is not absolutely perfect and needs to be nudged every day,” said Dr. David Berson, whose lab at Brown University studies how the eye communicates with the brain.

So-called photoreceptive cells in the retina absorb sunlight and transmit messages to a part of the brain called the suprachiasmatic nucleus (S.C.N.), which governs the internal clock. The S.C.N. adjusts the body to the environment by initiating the release of the hormone melatonin in the evening and cortisol in the morning.

Melatonin is thought to have many health-promoting functions, and studies have shown that people with low melatonin secretion, a marker for a dysfunctional S.C.N., have a higher incidence of many illnesses, including cancer, diabetes and heart disease.

It was not until 2002 that the eye’s role in synchronizing the circadian rhythm became clear. It was always believed that the well-known rods and cones, which provide conscious vision, were the eye’s only photoreceptors. But Dr. Berson’s team discovered that cells in the inner retina, called retinal ganglion cells, also had photoreceptors and that these cells communicated more directly with the brain.

These vital cells, it turns out, are especially responsive to the blue part of the light spectrum.

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Starving yourself on alternate days can make you live longer, according to scientists.
–A group of Americans have said that fasting on and off can boost brain power and help to lose weight at the same time.
–The National Institutes for Aging said their research was based on giving animals the bare minimum of calories required to keep them alive and results showed they lived up to twice as long.
–The diet has since been tested on humans and appears to protect the heart, circulatory system and brain against age-related diseases like Alzheimer’s.

‘Dietery energy restriction extends lifespan and protects the brain and cardiovascular system against age-related disease,’ said Mark Mattson, head of the laboratory of neurosciences at the NIA and professor of neuroscience at John Hopkins University in Baltimore.

‘We have found that dietary energy restriction, particularly when administered in intermittent bouts of major caloric restriction, such as alternative day fasting, activates cellular stress response pathways in neurones,’ he said to the Sunday Times.

In one set of experiments, a group of mice were only fed on alternate days while others were allowed to eat daily.

Both groups were given unlimited access to food on the days they were allowed to eat and eventually consumed the same amount of calories.

Professor Mattson said he found the mice fed on alternate days were more sensitive to insulin and needed to produce less of it.

High levels of the hormone, which is produced to control sugar levels after a meal or snack, are usually associated with lower brain power and are at a higher risk of diabetes.

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Two experiments were undertaken. For the first, 65 men and 65 women, all of an average age of 21, anonymously played a cooperation game where they could donate money via a computer program to a group fund. Donations were selfless acts, as all other players would benefit from the fund, whilst the donor wouldn’t necessarily receive anything in return.

Players did not know who they were playing with. They were observed by either someone of the same sex or opposite sex — two physically attractive volunteers, one man and one woman. Men were found to do significantly more good deeds when observed by the opposite sex. Whilst the number of good deeds made by women didn’t change, regardless of who observed.

For the second experiment, groups of males were formed. Males were asked to make a number of public donations. These increased when observed by an attractive female, where they were found to actively compete with one another. When observed by another male, however, donations didn’t increase.

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We conclude that ultrasound exposure in fetal life increases the risk of left-handedness in men, suggesting that prenatal ultrasound affects the fetal brain.

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piano improv

http://soundcloud.com/graehl/for-kevin-raw 

for-kevin-raw.mp3 Listen on Posterous

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Bad: The Turin Horse, The Decoy Bride, One Day

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fair: Broken Flowers, The Kid with a Bike, The Good, the Bad, the Weird, City Island, He Loves Me... He Loves Me Not, Noriko's Dinner Table

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bad: Sucker Punch, Khodokovsky, Real Steel, The Whistleblower

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(animated)

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poor: The Boy in the Striped Pyjamas

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Luke M. relates (see linked discussion):

Baboons... literally have been the textbook example of a highly aggressive, male-dominated, hierarchical society. Because these animals hunt, because they live in these aggressive troupes on the Savannah (just like we humans used to, and thus we evolved similarly), they have a constant baseline level of aggression which inevitably spills over into their social lives.

Scientists have never observed a baboon troupe that wasn't highly aggressive, and they have compelling reasons to think this is simply baboon nature, written into their genes. Inescapable.

Or at least, that was true until the 1980s, when Kenya experienced a tourism boom.

Sapolsky was a grad student, studying his first baboon troupe. A new tourist lodge was built at the edge of the forest where his baboons lived. The owners of the lodge dug a hole behind the lodge and dumped their trash there every morning, after which the males of several baboon troupes — including Sapolsky's — would fight over this pungent bounty.

Before too long, someone noticed the baboons didn't look too good. It turned out they had eaten some infected meat and developed tuberculosis, which kills baboons in weeks. Their hands rotted away, so they hobbled around on their elbows. Half the males in Sapolsky's troupe died.

This had a surprising effect. There was now almost no violence in the troupe. Males often reciprocated when females groomed them, and males even groomed other males. To a baboonologist, this was like watching Mike Tyson suddenly stop swinging in a heavyweight fight to start nuzzling Evander Holyfield. It never happened.

This was interesting, but Sapolsky moved to the other side of the park and began studying other baboons. His first troupe "scientifically ruined" by such a non-natural event. But really, he was just heartbroken. He never visited.

Six years later, Sapolsky wanted to show his girlfriend where he had studied his first troupe, and found that they were still there, and still surprisingly violence-free. This one troupe had apparently been so transformed by their unusual experience — and the continued availability of easy food — that they were now basically non-violent.

And then it hit him.

Only one of the males now in the troupe had been through the event. All the rest were new, and hadn't been raised in the tribe. The new males had come from the violent, dog-eat-dog world of normal baboon-land. But instead of coming into the new troupe and roughing everybody up as they always did, the new males had learned, "We don't do stuff like that here." They had unlearned their childhood culture and adapted to the new norms of the first baboon pacifists.

As it turned out, violence wasn't an unchanging part of baboon nature. In fact it changed rather quickly, when the right causal factor flipped, and — for this troupe and the new males coming in — it has stayed changed to this day.

Somehow, the violence had been largely circumstantial. It was just that the circumstances had always been the same.

Until they weren't.

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Voyager - one of the first digital cameras. Pretty good range on its wireless network, too :)

The dot is our sun.

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Robin Hanson notices some strong evidence that publicly traded companies under-invest:

The number of new businesses we get seems limited by the number of folks personally wealthy enough to start new businesses. So having more really rich folks benefits everyone via innovation.

Now I learn that very rich folks are crucial not only for business starts, but also for most investment that takes more than a year or so to payoff! Consider:

As is common in factories, [public firm] Standard [Motor Products] invests only in machinery that will earn back its cost within two years. (The Atlantic, Jan, p.66)

Why look at years-to-payback instead of return on investment? A new NBER paper on private vs. public firms makes the answer clear. Unless project gains can be very clearly proven to analysts, or perhaps so small and numerous to allow averaging over them, public firms are basically incapable of taking a loss on earnings this quarter in order to make gains several years later, no matter how big those gains. CEOs are strongly tempted to instead please analysts by grabbing higher short-term quarterly earnings. So we need the very rich to make long-term investments.

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I liked John Medina's Brain Rules, and my sister just had a baby, so I skimmed Brain Rules for Baby.

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good: Headhunters, Melancholia (extremely slow and dark, like all his films), Adventures of Tintin, A Separation, A Prophet, The Guard (underrated), The Others, Pursuit of Happyness, 50/50, The Ides of March, Tropa de Elite 2 (Elite Squad), Our Idiot Brother (underrated)

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California Verbal Learning Test (CVLT) (immediate and delayed), Spot-the-Word test (STW), Symbol Digit Modality test (SDMT) and Digit Backwards (DB). Groups of cannabis users were defined from self-reports across three waves as: ‘never’ (n= 420) ‘remain light’ (n= 71), ‘former light’ (n= 231), ‘remain heavy’ (n= 60), ‘former heavy’ (n= 60) and ‘always former’ (since start of study) (n= 657).

 baseline there were significant differences between cannabis groups on CVLT (immediate and delayed) and SDMT. However, after controlling for education, gender, gender × group and gender × wave, there were no significant between-group differences and only CVLT immediate recall reached adjusted statistically significant longitudinal change associated with changed cannabis use (group × wave P= 0.007). Specifically, former heavy users improved their performance relative to remaining heavy users (estimated marginal means: former heavy 6.1–7.5: remain heavy 6.4–6.6

That [marijuana makes you stupid], at least, has been the collective stereotype for decades. There’s even been some science to back it up, especially when the marijuana use begins at an early age. But now a different answer is beginning to emerge, thanks to an authoritative new study led by Robert Tait at the Australian National University. The scientists looked at the long-term cognitive effects of marijuana use in nearly 2,000 subjects between the ages of 20 and 24. The subjects were divided (based on self-reports) into several different categories, from total abstainers (n = 420) to “current light users” (n = 71) to “former heavy users” (n = 60). Over the course of eight years, the scientists gave the subjects a battery of standard cognitive tests, most of which focused on working memory, verbal memory and intelligence. One of the important advantages of this study is that the scientists controlled for a number of relevant variables, such as education and gender. In Time, Maia Szalavitz explains why this statistical adjustment is necessary:

The lower education levels of the pot smokers — and their greater likelihood of being male — had made it look like marijuana had significantly affected their intelligence. In fact, men simply tend to do worse than women on tests of verbal intelligence, while women generally underperform on math tests. The relative weighting of the tests made the impact of pot look worse than it was.

Once these population differences were corrected for, the long-term effects of marijuana use disappeared: The scientists found that “there were no significant between group differences.” In other words, the amount of pot consumed had no measurable impact on cognitive performance. The sole exception was performance on a test of short-term verbal memory, in which “current heavy users” performed slightly worse than former users. The researchers conclude that, contrary to earlier findings, the mind altering properties of marijuana are ephemeral and fleeting:

The adverse impacts of cannabis use on cognitive functions either appear to be related to pre-existing factors or are reversible in this community cohort even after potentially extended periods of use. These findings may be useful in motivating individuals to lower cannabis use, even after an extensive history of heavy intake.

This study builds on previous work by Harvard researchers demonstrating that the learning and memory impairments of heavy marijuana users typically vanish within 28 days of “smoking cessation.” (The slight impairments still existed, however, one week after smoking.) While several days might sound like a long hippocampal hangover, heavy alcohol users typically experience deficits that persist for several months, if not years. In other words, heavy marijuana use appears to be a lot less damaging than alcoholism.

Taken together, these studies demonstrate that popular stereotypes of marijuana users are unfair and untrue. While it’s definitely not a good idea to perform a cognitively demanding task (such as driving!) while stoned, smoking a joint probably also won’t lead to any measurable long-term deficits. The Dude, in other words, wasn’t dumb because he inhaled. He was dumb because he was The Dude. (All those White Russians probably didn’t help, either.)

Furthermore, there’s some intriguing evidence that marijuana can actually improve performance on some mental tests. A recent paper by scientists at University College, London looked at a phenomenon called semantic priming. This occurs when the activation of one word allows us to react more quickly to related words. For instance, the word “dog” might lead to decreased reaction times for “cat,” “pet” and “Lassie,” but won’t alter how quickly we react to “chair.”

Interestingly, the scientists found that marijuana seems to induce a state of hyper-priming, in which the reach of semantic priming extends to distantly related concepts. As a result, we hear “dog” and think of nouns that, in more sober circumstances, would seem rather disconnected, such as “leash” or “hair.” This state of hyper-priming helps explain why cannabis has been so often used as a creative fuel, as it seems to make the brain better at detecting those remote associations that lead to radically new ideas.

Why does marijuana increase access to far reaching intellectual connections? One possibility is that the beneficial effect of the drug is mediated by mood. Marijuana, after all, has long been used to quiet anxious nerves — big pharma is currently exploring targeted versions of THC as a next generation anxiolytic — as only a few puffs seem to dramatically increase feelings of relaxation and euphoria. (The technical term for this, of course, is getting stoned.) Furthermore, recent research has suggested that performance on various tests of remote associations and divergent thinking — a hallmark of creativity — are dramatically enhanced by such positive moods.

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