Brought on by darkness, seasonal disorder needs light

Brought on by darkness, seasonal disorder needs light

In a few days, the winter solstice will plunge us into the longest and darkest night of the year. Is it any surprise that we humans respond with a holiday season of relentless cheer and partying?

It doesn't work for everyone, though. As daylight wanes, millions begin to feel depressed, sluggish and socially withdrawn. They also tend to sleep more, eat more and have less sex. By spring or summer the symptoms abate, only to return the next autumn.

Once regarded skeptically by the experts, seasonal affective disorder, SAD for short, is now well established. Epidemiological studies estimate that its prevalence in the adult population ranges from 1.4 percent (Florida) to 9.7 percent (New Hampshire).

Researchers have noted a similarity between SAD symptoms and seasonal changes in other mammals, particularly those that sensibly pass the dark winter hibernating in a warm hole. Animals have brain circuits that sense day length and control the timing of seasonal behavior. Do humans do the same?

In 2001, Dr. Thomas Wehr and Dr. Norman Rosenthal, psychiatrists at the National Institute of Mental Health, ran an intriguing experiment. They studied two patient groups for 24 hours in winter and summer, one group with seasonal depression and one without.

A major biological signal tracking seasonal sunlight changes is melatonin, a brain chemical turned on by darkness and off by light. Wehr and Rosenthal found that the patients with seasonal depression had a longer duration of nocturnal melatonin secretion in the winter than in the summer, just as with other mammals with seasonal behavior.

Why did the normal patients show no seasonal change in melatonin secretion? One possibility is exposure to industrial light, which can suppress melatonin. Perhaps by keeping artificial light constant during the year, we can suppress the "natural" variation in melatonin experienced by SAD patients.

There might have been a survival advantage, a few hundred thousand years back, to slowing down and conserving energy — sleeping and eating more — in winter. Could people with seasonal depression be the unlucky descendants of those well-adapted hominids?

Regardless, no one with SAD has to wait for spring and summer to feel better. "Bright light in the early morning is a powerful, fast and effective treatment for seasonal depression," said Rosenthal, now a professor of clinical psychiatry at the Georgetown Medical School and author of "Winter Blues" (Guilford, 1998). "Light is a nutrient of sorts for these patients."

The timing of phototherapy is critical. "To determine the best time for light therapy, you need to know about a person's individual circadian rhythm," said Michael Terman, director of the Center for Light Treatment and Biological Rhythms at the Columbia University Medical Center.

People are most responsive to light therapy early in the morning, just when melatonin secretion begins to wane, about eight to nine hours after the nighttime surge begins.

How can the average person figure that out without a blood test? By a simple questionnaire that assesses "morningness" or "eveningness" and that strongly correlates with plasma melatonin levels, according to Terman.

The nonprofit Center for Environmental Therapeutics has a questionnaire on its Web site (www.cet.org).

Once you know the optimal time, the standard course is 30 minutes of fluorescent soft-white light at 10,000 lux a day. You may discover that you are most photoresponsive very early, depending on whether you are a lark (early to bed and early to rise) or an owl.

The effects of light therapy are fast, usually four to seven days, compared with antidepressants, which can take four to six weeks to work.

For treatment while sleeping, there is dawn simulation. You get your own 90-minute sunrise from a light on a timer that starts with starlight intensity and ends with the equivalent of shaded sun. This is less effective than bright light.

It may sound suspiciously close to snake oil, but the newest promising therapy for SAD is negative air ionization. Terman found it serendipitously when he used a negative ion generator as a placebo control for bright light, only to discover that high-flow negative ions had positive effects on mood.

Heated and air-conditioned environments are low in negative ion content. Humid places, forests and the shore are loaded with them. It makes you wonder whether there is something, after all, to those tales about the mistral and all those hot dry winds, full of bad positive ions, that supposedly drive people mad.

Of course, you might decide to drop the light and ions and head for a sunny, tropical vacation.

Leaving Computers On Helps Them Last Longer

Leaving Computers On Helps Them Last Longer

You are finished using your PC for the day. Should you turn it off or leave it on?

 
ON OR OFF?: Your computer is more likely to be damaged by a virus picked up from the Internet than by being turned off and on too much.

You take a deep breath, rub your tired eyes and prepare to push away from your personal computer after a lengthy instant message exchange, video viewing or analysis of your monthly budget—maybe all three. But before you exit cyberspace, a decision must be made: Should you shut the machine down, place it into "sleep" mode or do nothing at all?

How you end a computer session depends on how often you use the computer, your views on energy conservation (the amount of juice it uses while sitting idle), and what you have been told about how your decision will affect your investment's longevity: Will frequent starting and stopping cause its circuits to burn out sooner?

Rest easy, your computer is more likely to be damaged by a virus picked up from the Internet than by being turned off and on too much. They are also energy efficient: Such efficiency has reached the point where most PCs place themselves in sleep mode if they remain idle for a certain period of time. So your PC will likely slip into sleep mode anyway, even if you leave it on overnight.

Sleep mode itself, once a pretty unreliable option—you never knew if you would be able to wake your PC without having to reboot it—has been vastly improved with newer operating systems. If you want your PC to consume as little energy as possible when not in use, shut it down. If you want it to consume zero energy, you're going to have to unplug it.

Your PC can be in only three states: on, sleep or off (also called standby)—each of which draws some level of electric current. A PC that is "on" will either be actively processing information or sitting idle, depending on whether the user is typing a document, reading e-mail or has stepped away briefly. The amount of wattage drawn when the computer is on varies greatly depending on whether it is a laptop or a desktop PC. (The latter uses more energy because desktop power supplies are less efficient and require a separate and often larger, power-hungry monitor.) It also varies based on the type of work being done: Complex calculations requiring intensive processing are more power hungry, whereas writing or Web browsing consume far less electricity.

When a computer goes into sleep mode, it shuts down everything but its random access memory (RAM), a group of memory cells (which represent bits of data) that retains short-term data for easy access, thus preserving the computer's last active state—the running software, used log-ons and other settings—so that the user does not have to reboot when active use resumes. Sleep mode has gotten a bad rap in the past because, "with Windows operating systems prior to Vista [which debuted in late January 2007] the 'resume from sleep' mode has not been that reliable," says Ken Bosley, Hewlett-Packard brand manager for consumer desktop PCs. "Sometimes the resume fails and you have to reboot anyway."

"The usability benefits of leaving a desktop on appear to be growing as indicated in our focus groups," says Glenn Jystad, senior manager for desktop products at PC-maker Gateway, Inc., which in October 2007 was bought by Taiwan-based computer company Acer, Inc. "Nevertheless, it is prudent for home owners to manage their PCs power settings so as to not unnecessarily draw too much power and grow their electric bills." One trick Microsoft Windows Vista users can try is to select the "balanced" power setting, which causes the PC to go into sleep mode with one hour of nonuse, he adds.

The U.S. Environmental Protection Agency (EPA) confirms that putting desktop PCs in a low-power sleep mode after a period of inactivity can lead to annual energy savings of $15 to $45 per computer. The EPA breaks sleep mode down into two categories: "system standby" and "hibernate." System standby wakes up faster than hibernate (five to 10 seconds compared with 20 or more seconds) but does not save work in the event power is interrupted or lost. This is because in system standby the PC saves work to RAM, whereas in hibernate it saves to the hard disk, which records data magnetically, thereby retaining it even when the power is cut.

If the EPA's projected cost savings fail to dazzle, there are other incentives for using computers more efficiently. The EPA says that PCs adhering to its latest Energy Star specifications are expected to save consumers and businesses more than $1.8 billion in energy costs over the next five years and prevent greenhouse gas emissions equal to the annual output of 2.7 million vehicles. Desktop PCs meet Energy Star qualifications if they use two watts or less of electricity in system standby mode, five watts or less in sleep mode and no more than 60 watts in active mode. Laptops qualify under Energy Star if they use 0.5 watt or less in standby, five watts or less in sleep and 15 watts or less in active mode.

When it comes to judging whether sleep or standby causes more wear and tear on your computer, pick your poison. Whereas disk hard drives are most likely to crash during the process of turning off the computer, leaving the PC on causes the microprocessor to generate heat—more heat than if the system is shut down—that will wear down the electronics over time. "Some components will last longer if you shut down your computer, others won't," Bosley says.

As a general rule of thumb, he says, most electronics have some failure rate linked to the amount of hours they're in use. A few hundred dollars will buy you either a blazing-fast new microprocessor or a spacious, terabyte-size hard drive, so the replacement cost differences are negligible.

Of course, the importance of whether to power down or put your computer to sleep depends a lot on how much you use it. If you spend 20 minutes each night reviewing your e-mail, it's a waste of energy to leave your PC on all day. If you're continually on your computer, or go back several times a day, it's best to leave it in sleep mode between sessions. Another variable is the efficiency of the PC's processor. Slower ones use less energy but have to work longer and harder than more powerful CPUs. "It's like a car," Bosley says, "you can't talk about gas mileage without talking about the vehicle's performance."

Ultimately, if you want to leave your PC on most of the time, your best move is to buy one that meets the EPA's Energy Star efficiency standards—Energy Star–approved PCs consume less than half the amount of energy as products without this designation—and also to make sure your computer defaults into sleep mode if it is inactive for any length of time. That sort of compromise will make sure your computer is ready for action on a moment's notice without padding your utility bills.

The Human Instrument

The Human Instrument

When judged by its size, our vocal system fails to impress as a musical instrument. How then can singers produce all those remarkable sounds? 

AMAZINGLY FLEXIBLE, the human voice creates sounds as rich and complex as those of conventional musical instrumentsbut with much smaller equipment.
AARON GOODMAN

• Although the human vocal system is small, it manages to create sounds as varied and beautiful as those produced by a variety of musical instruments.
• All instruments have a sound source, a resonator that reinforces the basic sound and a radiator that transmits the sound to listeners.
• A human’s sound source is the vibrating vocal folds of the larynx; the resonator is the sound-boosting airway above the larynx; and the radiator is the opening at the mouth.
• The human voice can create such an impressive array of sounds because it relies on non­linear effects, in which small inputs yield surprisingly large outputs.

The human vocal system would not receive much acclaim if instrument makers placed it in a lineup of traditional orchestral instruments. Arranged by size, for example, the voice box (larynx)—and the airway it sits in—would be grouped with the piccolo, among the smallest of mechanical music makers. And yet experienced singers compete well with all man-made instruments, one on one and even paired with full orchestras. Recent investigations of how our singing voice generates a remarkable range of sounds have revealed surprising complexity in the behavior of the vocal system’s elements and in the ways they interact.

For more than half a century, scientists explained the voice’s ability to create song by invoking a so-called linear theory of speech acoustics, whereby the source of sound and the resonator of sound (or amplifier) work independently. Researchers have now learned, however, that nonlinear interactions—those in which source and resonator feed off each other—play an unexpectedly crucial role in generating human sound. Such insights now make it possible to describe how great singers produce those amazing sounds.

Credit Due: Was Sir Fred Hoyle Foiled--By Himself?

Credit Due: Was Sir Fred Hoyle Foiled--By Himself?

A colleague of the late Sir Fred Hoyle says his friend never got his due for explaining how the universe got its elements 

 
FRED HOYLE may have missed out on some of the credit for the theory of how stars formed the elements by leaving a simple equation out of a 1954 paper. Here he is on the campus of the California Institute of Technology in Pasadena in February 1967.

Sir Fred Hoyle, the late astrophysicist acclaimed for developing the theory of how stars forge hydrogen and helium into the heavier elements found throughout the universe, did not get the credit he deserved for a 1954 paper that outlined the idea, because he failed to spell out a key equation, a former colleague says.

Hoyle, who died in 2001 at the age of 86, was something of a tragic figure in science. Unlike the vast majority of cosmologists, he never accepted the big bang theory of the universe, preferring the idea of an unchanging or steady state cosmos. And in his later years he embraced the view that life on Earth originated in outer space. When journals refused to accept his papers exploring the idea, he reached out to the public directly by writing books for a popular audience.

Long before descending into scientific infamy, Hoyle made what should have been a lasting contributions with his 1954 paper, "The Synthesis of the Elements from Carbon to Nickel." In it, he laid out a process by which stars heavier than 10 suns would progressively burn hydrogen and helium at their cores into heavier elements through a series of nuclear fusion reactions. As such a star aged, it would end up structured like an onion, with the heaviest elements (iron and nickel) at the core and layers of progressively lighter elements toward the surface. When the star finally exploded in a supernova, it would scatter these elements into space, where they would seed still-forming star systems.

Prior to Hoyle's work, most experts believed that the elements had been born in a flurry of nuclear fusion during the big bang (now dated to around 13.7 billion years ago).

But instead of citing the 1954 study, Clayton says, researchers discussing fusional element formation, or nucleosynthesis, typically reference a 1957 paper co-authored by Hoyle and three colleagues, which went into greater detail but on other facets of the problem, says Donald Clayton, professor emeritus of physics and astronomy at Clemson University in South Carolina.

At a recent conference commemorating the 50th anniversary of that paper, known as B²FH for the initials of its authors (Geoffrey and Margaret Burbidge, now at the University of California, San Diego, along with the late Willy Fowler of the California Institute of Technology and Hoyle), Clayton said that of 30 major nucleosynthesis papers published between 1960 and 1973, 18 cited B²FH and only one gave the nod to Hoyle's 1954 paper.

Writing in Science, Clayton attributes the misplaced citation to the fact that neither paper included a relatively straightforward equation that was implicit in Hoyle's 1954 work. "Hoyle's equation," as Clayton calls it, relates the mass of heavy elements ejected by dying stars to the rate of their death and the change in abundance of the various isotopes produced during successive nuclear reactions.

"He was an expert mathematician. It's a shame he didn't decide to just write the equation," says Clayton, who was a student of Fowler's and collaborated with both Hoyle and him. A pithy equation gives other researchers "something to hang their hat on." Now researchers most likely cite B²FH without having read the founding papers in detail, he adds.

Stan Woosley, an astrophysicist at the University of California, Santa Cruz, and the organizer of the recent B²FH conference, cites more than half a dozen researchers who "contributed unique and important insights to the founding of nuclear astrophysics," including each of the B²FH authors. "But I agree," he notes, "that Hoyle's 1954 paper is underappreciated and undercited."

In Clayton's view, Hoyle missed his chance to secure his legacy in 1957 when he and Fowler, fresh from an astronomy conference at the Vatican, were editing a draft of the paper written by the Burbidges. The finished product "was a great paper, but they did not go over the ground Hoyle had laid out," says Clayton, who adds, "Hoyle was never very interested in proofreading."

Geoffrey Burbidge says that Hoyle "certainly solved the problem of the origin of the elements." As he recalls it, however, B²FH "was very much a collaboration." Hoyle, he says, was not the type to leave something important out of a paper just because editing it was a little time-consuming.

One thing everybody agrees on is that Hoyle was shortchanged in 1983, when Fowler shared the Nobel Prize in Physics (with Subramanyan Chandrasekhar) for his work on nucleosynthesis. Clayton says the Nobel Committee's decision probably had more to do with Hoyle's rejection of scientific orthodoxy than any missing equation.

"Fred marginalized himself," Clayton says. "He made himself look like a sorehead who only cared about the steady state universe and life from outer space. … He made himself look foolish."

What's in a (Latin) Name?

What's in a (Latin) Name?

The special genius behind the species and genus 

 

The greater roadrunner is officially classified as Geococcyx californianus. The lesser roadrunner is Geococcyx velox. And the more familiar cartoon Road Runner (beep beep) has been designated on different occasions as Accelerati incredibilus, Velocitus tremenjus, Birdibus zippibus, Speedipus rex and Morselus babyfatious tastius. Consistently unsuccessful in his attempts to catch Fastius tasty-us is Wile E. Coyote, himself variously classified as a representative of the species Carnivorous slobbius, Eatius birdius, Overconfidentii vulgaris, Poor schinookius or Caninus nervous rex. (Real coyotes are Canis latrans, which sounds like a bathroom used by Roman legionnaires.)

So who do we, and the Looney Tunes folks, have to thank for setting the ground rules that led to all this highfalutin Latinate humor? None other than Swedish naturalist Carl Linnaeus, who was so in love with naming things that he gave himself a few more: Carl Linné, Carl von Linné, Carolus Linnaeus and Caroli Linnaei, the name by which he proposed the standard genus-species system of taxonomic binomial nomenclature still used to keep track of all that life out there. The year 2007 was the tricentennial of Linnaeus’s birth, which shows that some people’s contributions give them a postmortem vita that’s not at all brevis.

American journalist and wag H. L. Mencken paid unwitting tribute to Linnaeus’s classification scheme when he dubbed a large percentage of the U.S. population Boobus americanus. (Don’t worry, he meant the other guys, not you.) Mencken described the perpetually bamboozled B. americanus as “a bird that knows no closed season,” which coincidentally describes the Road Runner, also known as Disappearialis quickius. Mencken, by the way, covered the famous Scopes trial, in which some Homo sapiens treated the notion that they were related to Gorilla gorilla and Pan troglodytes like it was a Yersinia pestis infection.

Among Mencken’s many pithy comments about H. sapiens is,  “An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup.” And in fact, mixing up any of the numerous species of the genus Rosa with Brassica oleracea (Capitata Group) is even nuttier (Bertholletia excelsa) in Latin. Preventing mix-ups is one reason why Linnaeus’s system comes in so handy: French president Nicolas Sarkozy might call it a moineau, Spain’s King Juan Carlos might call it a gorrión, and Vice President Dick Cheney might (or might not) call out “fire in the hole” before trying to blow it out of the sky, but the bird in question would be recognizable to all their science advisers as Passer domesticus. Which is also known in English as the house sparrow. And because common species names, even within a single language, lack the authority of the official Linnaean designations, the house sparrow is also known in English as the English sparrow. Help, is there a taxonomist in the house?

Linnaeus’s twin great works were the 1753 Species Planterum, in which he classified all the known species of vegetation, and the 1758 Systema Naturae, which celebrates its 250th anniversary this year and which was the first major effort at organizing the animal world. The Wikipedia entry on Linnaeus notes that because of his habit of naming all the living things he encountered, “he thought of himself as a second Adam.” The cover of Systema Naturae shows a man, presumably Linnaeus, tossing Latin titles to “new creatures as they are created in the Garden of Eden.” No shrinking member of the genus Viola was he.

Linnaeus appears to have occasionally abused his absolute appellative power. The New York Botanical Garden, which hosted a rare public display of Linnaeus’s own annotated copy of the Systema Naturae last November, notes on its Web site that “he got revenge on his critics by naming unpleasant plants and animals after them. For example, he named Siegesbeckia, an unattractive Asian weed that exudes foul-smelling liquid, for German botanist Johan Siegesbeck.” So Linnaeus was probably a pain in the Equus asinus. But without him, biology could not have become big-name science.