Now scientists claim to have come up with an answer to her changing moods – our eyes are sending mixed signals to the brain.

They believe Mona Lisa’s smile depends on what cells in the retina pick up the image and what channel the image is transmitted through in the brain.

Until recently, small corner grocery stores were seen by public health officials as part of the obesity problem.

The stores, predominantly family-owned, offered convenience, but the accent was on snack chips, canned goods and sugary drinks. Now, because they are often the sole source of groceries in areas with no full-size supermarket, the stores are becoming linchpins in public health campaigns.

“If you are educating people to make good choices, but those choices aren’t available nearby and they don’t have a car to drive out to the suburbs to the supermarket, or an hour to ride two buses to get there,” said Kai Siedenburg, of the Community Food Security Coalition, a group based in Portland, Ore., that promotes access to healthy food, “then it’s really hard for them to make good choices.”

At the height of the boom, art collectors scrambled to acquire works by top artists from rising markets including China, Russia, India and the Middle East. A serious approach to collecting meant trips to London, New York and Hong Kong several times a year for auctions, and mandatory stops at the art fairs in Cologne, Miami Beach, London, Shanghai and Basel, Switzerland.

Now, a full year since the recession gutted the global art market, collectors are canceling their trips. Some Westerners are now loath to dip into markets like Russian or Indian contemporary art, whose prices soared during the boom but whose long-term value is less established. Many are cutting back on expensive art-buying trips. And some collectors say they’re interested in supporting local artists, particularly at a time of economic hardship—the cultural equivalent of buying an American car instead of an import.

Unlike the independent highbrows and unself-conscious lowbrows, middlebrows, it seems, are so invested in “getting on in life” that they do not really like anything unless it has been approved by their betters. For Woolf and her heirs, middlebrows are inauthentic, meretricious bounders, slaves to fashion and propriety, aping a culture they cannot understand; they are the prototypes of Hyacinth Bucket in the BBC program Keeping Up Appearances, who answers her “pearl-white, slim-line, push-button telephone” with “The Bouquet residence, the lady of the house speaking.”

Of course, the only acceptable lowbrows are the ones who know their place, who have no aspirations to anything better, such as Hyacinth’s unpretentious sister, Daisy, and her unemployed husband, Onslow, the sort of bloke who attends football matches wearing a cap that holds two cans of beer.

As the Harper’s Magazine editor Russell Lynes argued in his 1949 essay “Highbrow, Lowbrow, Middlebrow,” the ideal world for Woolf is a caste system in which billions of bovine proles produce the raw materials for a coterie of sensitive, highbrow ectomorphs who spring fully formed from the head of Sir Leslie Stephen. At the very least, lowbrows with upward aspirations should have the courtesy to keep themselves out of sight until they complete their passage through the awkward age of the middlebrow.

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Figuring out young people has always been a chore, but today it’s also an industry. Colleges and corporations pay experts big bucks to help them understand the fresh-faced hordes that pack the nation’s dorms and office buildings. As in any business, there’s variety as well as competition. One speaker will describe youngsters as the brightest bunch of do-gooders in modern history. Another will call them self-involved knuckleheads. Depending on the prediction, this generation either will save the planet, one soup kitchen at a time, or crash-land on a lonely moon where nobody ever reads.

As a book-obsessed suburban adolescent, I read Jack Kerouac, Henry Miller and the fantastical neogothic fiction of Angela Carter, and attempted to cultivate the dress and persona of a woman who drank her coffee black and her scotch straight. I wanted to hang out with artists and go to wild, all-night parties where everyone listened to jazz, smoked cigarettes and understood poetry. There didn’t seem to be much of that at my sixth-form – though I did acquire a boyfriend who was taking art A-level and had read Naked Lunch – but I was determined at least to look the part. Apparently channelling one of Miller’s Parisian lowlifes crossed with a Carter character circa 1977, for some time I wore a lot of black eyeliner and dressed only in a short, crimson petticoat, brown T-bar platforms and a long, strangely smelling sheepskin coat from Camden market. (The coat was the closest I could get to the fur my fantasy outfit demanded, which doesn’t really excuse it.)

Beverly Lewis, who sets her novels among the Amish in Pennsylvania, has sold 13.5 million copies of her books. Wanda Brunstetter’s novels take place in Amish communities in Ohio, Indiana, Missouri and Pennsylvania, and have sold more than four million copies. Publishing house Thomas Nelson plans to release five Amish novels this fall, and six more in 2010.

Barnes & Noble book buyer Jane Love said Amish novels currently account for 15 of the chain’s top 100 religious fiction titles. “It’s almost like you put a person with a bonnet or an Amish field in the background and it automatically starts to sell well,” Ms. Love said.

I’m fairly certain I recently passed a rather pathetic tipping point, and now own more unread books and unwatched DVDs than my remaining lifespan will be able to sustain. I can’t possibly read all these pages, watch all these movies, before the grim reaper comes knocking. The bastard things are going to outlive me. It’s not fair. They can’t even breathe.

The relationship between black women and their hair goes well beyond the occasional bad hair day. It’s about race, politics, and the expectations of women to conform to a certain standard. It’s a great film, and one that teases out (no pun intended) the complex business of having hair that makes a political statement, whether you like it or not.

But without making light of all the messy historical, political, and cultural unpleasantness tied up in black women’s hair, it’s worth discussing another point: no one I know, black or white, woman or man, is ever really satisfied with their hair. I tested my hypothesis when I visited Francky, the proprietor of Francky L’Official Salon in Manhattan Salon on the Upper East Side. How many women, we asked, liked their hair? None, he said. They always wants something totally different than what they have – though in fairness, those who visit Francky are there willing to pay big bucks for styles, blowouts, and Keratin straightening treatments.