Monday, February 26, 2007

Tiffany Granath and the Growler

In case you missed it, Tiffany Granath of PlayBoy Radio was a hoot when she interviewed me this afternoon. (I'll post a few snippets of the show on my iTunes podcast in a day or two.) We talked about everything from the reasons humans have sex to the the fluid mechanics of blood flow during arousal to the physics of the nervous system.

Even better, we took a few moments to discuss a sexual technique that I call the Growler. If you listened in, you heard it first on Tiffany's Afternoon Advice.

A Growler is a low frequency hummer. If you've never heard of a hummer, it's just oral sex, except that the person performing it hums as they work. The extra vibration adds spice to the experience, whether you're doing to it a man or a woman.

So, why is it a Growler? Your nerves transmit signals in a way that limits the vibrations you can feel in your hands, feet, genitals, and basically any other body part besides your ears, to a maximum of 500 hertz or so. That's about the pitch of the A note above middle C on the piano. To give a good hummer, you should stick to pitches somewhere lower on the scale.

But as you lower your pitch, the sound turns into more of a purr or growl than a hum, hence the name "Growler." You should play around with the tone to find the right note. I can tell you that it feels great, and women seem to love getting growlers too (perhaps even more than we guys do).

Thanks to Tiffany for letting me explain it on her show!

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Thursday, February 15, 2007

The HPV Vaccine

If someone had asked me a few months ago whether there could possibly be an objection to a vaccine that could prevent cancer in thousands of people each year, I would have confidently answered "Absolutely not."

And yet, here we are, facing debates over the morality, cost, and efficacy of an FDA approved HPV vaccine. Human papillomaviruses cause more than ten thousand cases of cervical cancers and four thousand deaths annually in the US alone. The numbers are much worse in developing countries where sex education is inadequate, screening is rare, and cancer treatments are prohibitively expensive.

The new vaccine, which is being actively (and clumsily) marketed by Merck pharmaceuticals, appears to effectively prevent certain virus strains that are responsible for two thirds of HPV-related cancer cases.

I'm sure that no one will be surprised to learn that I support HPV vaccinations. Anything that extends life and reduces suffering gets my support. The fact that it also makes sex safer only strengthens my conviction.

If you've been following the public debate, you've probably noticed that the connection to sex is one of the chief objections that some vocal opponents to the vaccine point to.

One opponent, conservative Jill Stanek, focuses on the immoral origins of HPV cases. "[Like smoking,] HPV is also the consequence of a destructive behavior, sex outside of marriage."

Besides that fact that sex outside of marriage is both widespread and healthy (if you take reasonable precautions), Jill has a pretty odd idea about how HPV is transmitted. I can't imagine that many viruses can distinguish between sex inside and outside of marriage. If your partner or husband or wife carries the virus, you may be exposed during sex.

I suppose a woman could search for a mate who claims to be a virgin, and then take him at his word. Or she could simply get the vaccine and protect herself.

But the biggest issue I see is that vaccines like the Merck HPV vaccine don't just protect the individual, they protect the community as a whole. A Stanford University study from 2004 showed that HPV-related cancers could be reduced by 64% as a result of a vaccination program targeting prepubescent girls. The benefits extend beyond vaccinated girls. Both men and unvaccinated women will be safer as a result of herd immunity, even if as few as 40% of young girls are immunized. (Of course, the greatest protection will go to the vaccinated girls.)

Abstinence-based objections to HPV vaccinations strike me as both unrealistic and antisocial. It's not just about you, Jill Stanek, it's about protecting society as a whole. Stanek points out that an HPV vaccine will not protect us from other STDs. Such reasoning is so absurd that I can't imagine where to start. Were Small Pox vaccinations a bad idea because they didn't also prevent polio?

Another, more frivolous and short sighted objection is the fact that Merck will make a bundle off of the vaccine. I don't trust the altruism of major corporations (they're set up to make money, not save the world), and I certainly think we should look closely at any drug they provide. That's why we have the FDA. But the lack of profit in vaccinations is one reason we are facing a potential crisis the next time a highly-contagious and virulent flu hits our shores. In this case, it looks as though an HPV vaccine will lead both to profits and improved societal health.

Overall, the Stanford study concludes that the additional cost of the vaccine will raise average lifetime medical expenses of people in the US by $245, or about 0.6%, while saving thousands of lives every year. How can a compassionate person possibly object?

Think of all the additional people who will be alive to hear the abstinence messages that folks like Stanek promote.

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Tuesday, February 13, 2007

Buzz Skyline on Playboy Radio, Feb. 26

Mark your calendars!

I will be a guest on Playboy Radio's Afternoon Advice with Tiffany Granath on February 26 at 1:00PM PST (4:00PM EST).

The show is on SIRIUS radio's Playboy Radio channel 198. You can call in toll free to ask questions at 1-877-205-9796.

I'm looking forward to hearing from you on the air.

A few months ago, I never would have imagined that physics could be a topic on channel like Playboy Radio. I'm thrilled!

Now, I wonder if I could convince Physics World to include a centerfold model just to bring the whole thing full circle.

Even better, maybe we could raise enough of a public outcry to get science journalist Karen Hopkin to resurrect her Studmuffins of Science wall calendar.

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Wednesday, February 07, 2007

Valentine's Day Physics

Science is probably the farthest thing from your mind as you make plans for Valentine's Day next week. But for this popular holiday dedicated to romance, it occurred to me that you should keep a few of the suggestions from earlier Physics of Sex posts in mind.

Listen to the podcast with Text-to-Speech roboreaders Kate and Paul.

If you're a regular reader, suggestion number 5 is a new one that you haven't seen here yet. The rest are taken from earlier posts.

1. Opt for a low fat dinner. Fat from your meal rapidly moves into your blood, making it sticky, thick and more difficult for your heart to pump around. Reduced blood flow dampens erectile vigor (in the genitals of both men and women), and can reduce lubrication in women. So skip the foie gras on the 14th. Salads and other low fat foods are sexier for your Valentine’s Day dinner. See the entry Pumped Up and Ready for Love, part 2 for more information.

2. Tune your bed and body for better sex. Different beds have different rhythms: firm beds are better for faster sex, and soft beds are better for slower loving. For the most versatility, start with a firm bed and add pillows or thick comforters to slow things down. If you want to take even more control of the pace, experiment with sexual positions. You will find that various positions often encourage distinct natural rhythms. See Sexual Rhythms for more details.

3. Mix it up for sensory bliss. The sensory cells that respond to touch, temperature and other information tune out sensations that don’t change much. (That’s why you may forget about the sunglasses resting on top of your head, for example.) So mix things up in bed – change how and where you touch your lover to keep the sensory cells firing and the excitement levels up. See Sex and Sensibility, part 1

4. Keep going longer with sensory repetition. If you or your lover suffer from premature ejaculation, you may be able to stave off the inevitable with the start-stop method. (The method is essentially the opposite of the suggestion above.) Just as the sensory cells and nerves in your scalp soon forget about the sunglasses stowed there, repeatedly taking a man to the brink of orgasm and stopping briefly makes the sensory system less responsive, and can help him last longer in bed. See Sex and Sensibility, part 1

5. Hum a low pitched tune. Human ears can detect high frequencies, but the nerves in the rest of your body can’t register vibrations much over 500 hertz (roughly the B note above middle C on the piano). So if you give the gift of a hummer this Valentine’s Day, keep the pitch low for the best effect. The details of this suggestion will be in the upcoming post Sex and Sensibility, part2.

6. If you still need to find a Valentine's Day date, try looking the physics way. I can't guarantee results, but researchers have found that some approaches are better than others when it comes to cruising for mates. (Valentine's Day is a week away, so you still have one more weekend to try it out.) The details are in last week's post The Physics Guide to Hooking Up.

Before Valentine's Day gets here, check out other Physics of Sex suggestions in the entry Skip to the Tips.

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Saturday, February 03, 2007

Warning: E. Coli Bacteria Can Swim Upstream

Here's a bit of disquieting research news - the bacteria E. coli tend to swim upstream in flowing liquids. The revelation, which appears in a paper to be published Monday, February 5 in the journal Physical Review Letters, could explain how the bacteria manage to make their way far up the urinary tract to cause pyelonephritis, a particularly nasty kidney infection.

Yale University researchers Jane Hill, Jonathan McMurry and Hur Koser collaborated with Ozge Kalkanci of Bogazici University in Istanbul on the work, which they believe is the first observation of the natural tendency of bacteria to swim upstream.

The researchers discovered the phenomenon by filming E. coli being swept along in tiny channels filled with flowing liquid. The bacteria tended to swim to their left (when viewed from above) as they were washed downstream. Eventually, their leftward swimming caused them to move toward the side of the channel, where they promptly turned around to swim back upstream. You can watch the behavior yourself in a video supplement to the paper that the researchers recorded. (The crosshairs in the video highlight the path of one of the bacteria.)

It seems that the leftward swimming and upstream migration result from the mechanical design of the bacteria. E. coli are propelled by whip-like flagella that push the bacteria along by rotating counterclockwise. Their cell bodies rotate clockwise in response to the torque of their twisting flagalla. The combination of motions cause E. coli to swim to the left when they encounter a surface in slowly moving or still fluid - an effect that has been observed in earlier studies.

The surprising result in the recent experiment, however, is that the motions also cause the bacteria to face upstream when they are submersed in a liquid flowing rapidly along a surface, in a manner that the researchers say is "much like a weather vane orienting into the wind."

The researchers suggest that the behavior could explain the incidence of infections in patients fitted with catheters, and could be the cause of the biofilms that form inside some plumbing systems. They even speculate that leaving a running hose in contact with the ground could lead to bacterial migrations out of the dirt and into the toilet tanks and water heater inside your house.

You might wonder what's the Physics of Sex connection to E. coli paddling upstream. Well, if you consider where the largest population of E. coli is in the human body, then you and your partner have yet another excellent reason to use condoms if you happen to practice anal sex. You wouldn't want to give those nasty fellas a chance to swim up anyone's urethra, would you?

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