Doctor doggie: An HMO who fetches slippers

Q. What does "Dr. Dog" know about your health? ­-R. T. Tin

 A. Don't sell Rover short, for along with cases of canines wresting their owners out of bed just before an earthquake or tornado strikes are the many documented instances of dogs warning their special people of an imminent medical problem, says Exploring magazine of the Exploratorium Science Museum.

Author Rupert Sheldrake tells of a collie named Molly that senses her owner Lise's epileptic seizures half an hour in advance, then starts staring, barking and licking to alert her. Whether Molly is sensing subtle muscular tremors, electrical disturbances, a distinctive odor, or something else, this type of canine capability underlies formation of Support Dogs and the Seizure Alert Dog Assn.

The journal Diabetic Medicine reported on a study of 43 pet-owning patients, 14 of whom said their dogs could sense episodes of low blood sugar– possibly based on body odor.

Then there's the case of Marilyn, whose Shetland sheepdog Tricia took to sniffing and nuzzling an area of the woman's back around a small mole, reports psychologist Stanley Coren in What Do Dogs Know? The dog grew more and more insistent, until Marilyn finally went to her doctor– and was stunned to get a diagnosis of melanoma. "Tricia's early warning probably saved Marilyn's life."

As a researcher told Coren, "Inspection by a dog may one day become a routine part of cancer screening."

Q. Stands to reason that a plane flying into the wind will be slowed compared to one flying with a tailwind. By how much? Might a plane in a stiff wind wind up flying backward? ­W. W. Corrigan

 A. Airspeed = Ground Speed - Wind Speed, plain and simple. Think of aircraft as traveling on a treadmill of air, says Elizabeth Wood in Science from Your Airplane Window. Going by a posted United schedule, says Purdue aerospace engineering professor Steven Collicott, "I see it takes six hours to fly nonstop from New York to Los Angeles, but only five hours to return. At this latitude, the prevailing winds and jet streams are on average west to east. One hour out of six may not be much to someone working a notebook computer, but for someone traveling with four kids, it is."

Sure, it's possible for a small craft to fly into a strong wind and wind up going backwards, "but it has never happened when I'm around," says Collicott. Yet you see birds doing this all the time, flying stationary if not drifting backwards.

On a historic note, one NASA website reports that the Wright brothers' plane flew at 35 mph airspeed into a 25 mph Kitty Hawk headwind, making for a groundspeed of 10 mph.

"That's likely why Wilbur was able to run alongside the airplane." To reduce initial necessary groundspeed, adds Collicott, planes (as well as birds) generally take off into the wind, with Navy aircraft often aided by the carrier steaming rapidly upwind.

Q. Puzzling survey results: The geography majors at the University of North Carolina reported an average starting salary far higher than geography majors at other schools. So, you savvy statistical types, take a stab at a possible reason... a) UNC has a superior geography faculty; b) UNC attracts superior geography students; c) UNC students are bigger fibbers on surveys; d) other. ­A. Vespucci

 A. Check "other," by the name of Michael Jordan, the very highly paid Chicago Bulls basketball superstar and UNC geography major, say Jeffrey O. Bennett et al. in Using and Understanding Mathematics. People often get these confused, but "mean" (average of all the numbers), "median" (as many numbers above this figure as below), and "mode" (most common number in a list) are totally different statistical animals. Only takes one phenomenal "outlier" to make a mockery of a mean, as in the UNC case. The median here would have been more defensible.

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