20 August 2010 PM

Science: why second hand smoke (even a little) is bad:

Scientists led by Dr. Ronald Crystal at Weill Cornell Medical College documented changes in genetic activity among nonsmokers triggered by exposure to secondhand cigarette smoke. Public-health bans on smoking have been fueled by strong population-based data that links exposure to secondhand cigarette smoke and a higher incidence of lung diseases such as emphysema and even lung cancer, but do not establish a biological cause for the correlation. Now, for the first time, researchers can point to one possible cause: the passive recipient’s genes are actually being affected. (See a new recipe for longevity that says no to smoking.)

Crystal’s team devised a study in which 121 volunteers – some of whom smoked and some of whom had never smoked – agreed to have samples of their airway cells studied for genetic activity. The subjects also provided urine so the researchers could measure the amount of nicotine and its metabolites, like cotinine, for an objective record of their exposure to cigarette smoke.

Airway cells that line the bronchus, from the trachea all the way to the tiny alveoli deep in the lungs, are the first cells that confront cigarette smoke, whether it is inhaled directly from a cigarette or secondhand from the environment. Crystal’s group hypothesized that any deterioration in lung function associated with cancer or chronic obstructive pulmonary disease, including emphysema and bronchitis, in which the lungs lose their ability to take in air, would begin with these cells. (See TIME’s guide for good health at every age.)

And indeed, that’s what he and his team found. The researchers removed airway cells from the volunteers using a bronchoscope and tested all 25,000 identified human genes in them to determine which ones were active – either turned on or off – in response to cigarettes. They narrowed the search to 372 genes that were active among the smokers but not in the cells of the nonsmokers. Based on the level of nicotine in the urine, the scientists also divided the volunteers into three groups: smokers, who showed the highest level of the tobacco metabolites; nonsmokers, who showed none of these compounds and a low-exposure group who fell in between. Comparing the 372 genes among these three groups, they found that the low-exposure group shared 34% of the same active genes with nonsmokers and 11% of the same gene activity with smokers. The low-exposure group included both nonsmokers who have never lit up as well as those who admitted to smoking only occasionally. [...]

Food: “locally grown” does NOT mean “smaller carbon footprint”, though there might be other reasons to buy locally grown stuff (e. g., taste, support your neighbor, etc.):

[...]One popular and oft-repeated statistic is that it takes 36 (sometimes it’s 97) calories of fossil fuel energy to bring one calorie of iceberg lettuce from California to the East Coast. That’s an apples and oranges (or maybe apples and rocks) comparison to begin with, because you can’t eat petroleum or burn iceberg lettuce.

It is also an almost complete misrepresentation of reality, as those numbers reflect the entire energy cost of producing lettuce from seed to dinner table, not just transportation. Studies have shown that whether it’s grown in California or Maine, or whether it’s organic or conventional, about 5,000 calories of energy go into one pound of lettuce. Given how efficient trains and tractor-trailers are, shipping a head of lettuce across the country actually adds next to nothing to the total energy bill.

It takes about a tablespoon of diesel fuel to move one pound of freight 3,000 miles by rail; that works out to about 100 calories of energy. If it goes by truck, it’s about 300 calories, still a negligible amount in the overall picture. (For those checking the calculations at home, these are “large calories,” or kilocalories, the units used for food value.) Overall, transportation accounts for about 14 percent of the total energy consumed by the American food system.

Other favorite targets of sustainability advocates include the fertilizers and chemicals used in modern farming. But their share of the food system’s energy use is even lower, about 8 percent.

The real energy hog, it turns out, is not industrial agriculture at all, but you and me. Home preparation and storage account for 32 percent of all energy use in our food system, the largest component by far. [...]

New York Mosque, again: Millard Fillmore’s Bathtub has an interesting post pointing out that Hiroshima does have several American things near ground zero and that Pearl Harbor has a Japanese cultural center. Surf there to see the satellite photo and to read the title of his post.

In fact, other nations are lampooning us (e. g., “outrage over plans to build a library next to Sarah Palin“).

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