Happy Cinco de Mayo everyone! Down with that imperialist aggressor Napoleon III! (The painting to the right is Manet's Execution of Maximillian. Supposedly, the chap on the right looks like Napoleon III, in a zinger to his administration which Manet viewed as responsible for Maximillian's death.)
Cosmic Variance has a great post on the physics of chocolate and why it doesn't always solidify the way you want it to:
If you've ever tried to use chocolate in its melted form, you've probably discovered that chocolate has a number of peculiarities that frequently thwart your best culinary efforts. For example, if your melted chocolate becomes contaminated with an errant drop of water, the chocolate siezes up. If you try to reharden chocolate that's been melted (say, in making chocolate covered strawberries), you're frequently left with a matte finish and crumbly texture that in no way resembles the dark glossy chocolate you began with.
The reasons for this should be familiar to any solid state physicist (or at least, they were to the one who made my wedding cake and first clued me in). Cocoa butter, one of the dominant ingredients in chocolate, contains several triglycerides that lock into a crystal form when cooled. However, there is not just one form that the triglycerides can lock into, but six of them (beta(I) through beta(VI)). Each successive form is more stable and has a higher melting point. Almost all commercial chocolate is in the beta(V) form -- from what I can tell, you only get to sample beta(VI) in the afterlife, if you've been very, very good. When chocolate goes all wrong, it is usually a failure of the melted and cooled chocolate to recrystallize into the beta(V) state.
Mothers are less likely to get their younger daughters vaccinated for HPV in part due to fears about precocious sexual activity. Never mind that the vaccine works much better the younger you have them vaccinated:
In the study, while 86 percent of moms intended to vaccinate a 16- to 18-year-old daughter, and 68 percent intended to vaccinate a 13- to 15-year-old daughter, fewer than half -- only 48 percent -- intended to vaccinate a 9- to 12-year-old daughter, according to the data analyzed by Dr. Kahn and her colleagues. "Mothers' intention to vaccinate against HPV is lowest for the younger daughters. Yet, younger girls are more likely than older girls to benefit from vaccination, which is why the CDC recommends that they be targeted for vaccination. This discrepancy between mothers' attitudes and CDC recommendations represents a challenge for health care providers."
"We found that mothers' beliefs about HPV vaccination are the most powerful determinants of whether they intend to vaccinate their daughters at this age. The findings of our study, in combination with results of the evolving literature on HPV vaccine acceptability, provide information that can be used to improve moms' acceptance of HPV vaccination for their younger daughters."
Factors independently associated with intention to vaccinate a younger daughter included belief that one's daughter should get a regular Pap screen and beliefs about HPV vaccines. The seven-item scale measuring beliefs about HPV vaccines included perceived benefits to HPV vaccination (such as whether that vaccination will protect one's daughter against cervical cancer), perceived barriers to vaccination (such as whether that vaccination may lead to riskier sexual behaviors), belief that the daughter is at risk for HPV infection, belief that HPV-related diseases such as cervical cancer are serious, and belief that one's doctor would recommend vaccination.
Dr. Kahn said that the most powerful individual predictors that were most associated with likelihood to vaccinate their younger daughters were (in order): belief that HPV vaccination would provide protection against cervical cancer, belief that vaccinated girls would not practice riskier sex, belief that one's daughter's clinician would recommend HPV vaccines for her, and belief that one's daughter is at risk for HPV infection.
New York's regulations mandating calories of food be posted in fast food restaurants have gone into effect. The City Room at the NYTimes rates the thus-far mixed compliance. My take: in this time of high food prices, it gives me great comfort to see the NY city government going to such lengths to reiterate information I already had before. I deeply appreciate calorie counts being clubbed over my head, and I simply love the greater costs that such burdensome regulations imply. Thank you so much.
A delightful post in which Chad explains relativity to his dog:
"Why do they call relativity 'relativity?' Why not something cooler, like Superfast Timeslowing Squirrelcatching Dynamics?"
"Well, for starters, that's a bad name for a physics theory. Physicists don't care much about squirrels. More importantly, though, the name 'Relativity' comes from one of the theory's most basic elements: the idea that relative motion is the only thing that matters. There is no absolute frame of reference against which we can measure the motion of everything in the universe." The light changes, and I start driving again.
"Yeah, but that's silly. Of course there's a fixed frame of reference."
"Really? What is it?"
"Well, my house, silly. And the yard, with the big oak tree. And the other tree. And the other other tree. And--"
"OK, ok, I get it."
"The house is where I keep my stuff!"
Read the whole thing.