2012-12-30聽力
SA 60s Science
Forest Canopy Color Reveals CO2 Uptake
When autumn rolls around, the leaf peepers come out in force. Armed with
digital cameras, they record the most spectacular displays of fall
foliage. Well according to a study in the journal Functional Ecology [Toshie Mizunuma et al., The
relationship between carbon dioxide uptake and canopy colour from two
camera systems in a deciduous forest in southern England], those images may be more than just pretty pictures. They may represent a new way to monitor climate change.
Trees take carbon dioxide, or CO2, from the atmosphere and convert it
into biomass. By sopping up CO2 they help to stabilize the climate. But
at the same time, they’re also affected by climate, for example, budding
earlier in the season as global temperatures rise.To understand how all this balances out, ecologists monitor how forests take up CO2. It’s a costly business that involves using a network of 500 instrument towers worldwide. So researchers got to wondering whether there might be an easier way to keep an eye on photosynthesis. And they found that digital cameras do the trick.
Analyzing two years’ worth of snaps taken every half hour in a forest in southern England, the researchers discovered that a tree’s leafy colors provide a good proxy for its photosynthetic productivity. So next time you go for a walk in the woods, take only photos. And leave only data points.
Humidity Levels Explain U.S. Flu Winter Peak
Cases of the flu peak in winter in the U.S. But why? A new study suggests it’s not the heat, but the humidity. Or lack thereof. Because in temperate regions, the influenza virus fares best when the weather is dry. That’s according to work published in the journal PLoS One. [Wan Yang, Subbiah Elankumaran and Linsey C. Marr, Relationship between Humidity and Influenza A Viability in Droplets and Implications for Influenza’s Seasonality]Scientists have long debated why flu erupts when the days grow chilly. Is it that we spend more time cooped up together indoors? Or is there something about the virus that likes it cold and dry? To find out, researchers suspended influenza virus in a solution that mimics human mucus. They incubated this infectious soup at different humidities and measured viral survival.
And they found that at low humidity, the fake mucus dries up and the virus does just fine. But when the humidity tops 50%, the droplets only partially evaporate, leaving behind a solution that’s too salty for the virus to thrive.
Interestingly, the virus does well again when the humidity reaches 100 percent, evaporation stops and the salinity of the mucus bath is juuust right. That could explain why the flu prefers to hit the tropics in rainy season. And why you should always keep your nose clean, but moist.
Telecommuters Work Longer Hours than Office Goers
When I say “telecommuting,” do you picture yourself easing into the
workday in a pair of fuzzy slippers? Well, so does your boss. But the
reality is, you’re both dreaming. Because a new study shows that folks
who work at home at least some of the time put in more hours than those
who stay at the office. That’s according to work published in the
journal Monthly Labor Review. [Mary C. Noonan and Jennifer L. Glass, The hard truth about telecommuting]
Telecommuting for a portion of the workweek certain has its appeal. Avoiding the time and cost involved in commuting and presumably having a more flexible schedule and a better work-life balance are all potential pluses. But are employees really able to take advantage of such work-at-home perks?
Researchers took advantage of labor information from census bureau surveys and were surprised by what they found. First off, the proportion of people who work remotely remained unchanged from the mid-’90s to the mid-2000s the most recent data available. Second, those who do telecommute are more likely to work overtime, an additional 5 to 7 hours on top of the standard 40.
Which means that people who work from the comfort of home are not slackers in slippers. They’re more likely tech-savvy self-starters—who don’t know when to stop.
Telecommuting for a portion of the workweek certain has its appeal. Avoiding the time and cost involved in commuting and presumably having a more flexible schedule and a better work-life balance are all potential pluses. But are employees really able to take advantage of such work-at-home perks?
Researchers took advantage of labor information from census bureau surveys and were surprised by what they found. First off, the proportion of people who work remotely remained unchanged from the mid-’90s to the mid-2000s the most recent data available. Second, those who do telecommute are more likely to work overtime, an additional 5 to 7 hours on top of the standard 40.
Which means that people who work from the comfort of home are not slackers in slippers. They’re more likely tech-savvy self-starters—who don’t know when to stop.