Science in fiction affects our ability to understand science in real life. For instance, you might already be familiar with the idea that detective shows on TV, particularly forensics shows like CSI, might be influencing what juries expect to see in a courtroom.
This is called the "CSI effect" and it's hotly debated. Some prosecutors think it has a real impact on jury decisions—if they don't get the fancy, scientific evidence they've been conditioned to expect then they won't convict. Meanwhile, though, empirical evidence seems to show a more complicated pattern. Surveys of more than 2000 Michigan jurors found that, while people were heavily expecting to see some high-tech forensic evidence during trials, that expectation probably had more to do with the general proliferation of technology throughout society. More interestingly, that broad expectation didn't seem to definitively influence how jurors voted during a specific trial. In other words: The jury is still out. (*Puts on sunglasses*)
A FRONTLINE documentary that airs tomorrow centers around an interesting corollary on this issue: Whether or not shows like CSI influence juries to expect more technology, they do present a wildly inaccurate portrait of how accurate that technology is. The reality is, many of the tools and techniques used in detective work have never been scientifically verified. We don't know that they actually tell us what they purport to tell us. Other forensic technologies do work, but only if you use them right—and there's no across-the-board standard guaranteeing that happens.
Even ideas you think you can trust implicitly—like fingerprint evidence—turn out to have serious flaws that are seriously under-appreciated by cops, lawyers, judges, and juries. Read the rest
In the course of preparing for a panel here at the Conference on World Affairs, I ran across a 2009 editorial by environmental journalist Fred Pearce, in which he explains why current global population trends aren't as horrific as they're often made out to be. I thought you should read it.
Global population is going up, Pearce writes, but that's not the same thing as saying that birth rates are going up. And, in the long run, that distinction matters. Around the world—not just in the West—human birthrates are decreasing. And they've been decreasing for a really long time.
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Wherever most kids survive to adulthood, women stop having so many. That is the main reason why the number of children born to an average woman around the world has been in decline for half a century now. After peaking at between 5 and 6 per woman, it is now down to 2.6.
This is getting close to the “replacement fertility level” which, after allowing for a natural excess of boys born and women who don’t reach adulthood, is about 2.3. The UN expects global fertility to fall to 1.85 children per woman by mid-century. While a demographic “bulge” of women of child-bearing age keeps the world’s population rising for now, continuing declines in fertility will cause the world’s population to stabilize by mid-century and then probably to begin falling.
Far from ballooning, each generation will be smaller than the last. So the ecological footprint of future generations could diminish. That means we can have a shot at estimating the long-term impact of children from different countries down the generations.
A key component of antibiotic resistance is the over-use of antibiotics. We talk about this a lot in the context of over-the-counter antibacterial cleansers, but there's a doctor's office side to this story, as well.
When sick people come into a doctor's office, part of what they are looking for is psychological wellness. They want to feel like somebody has listened to them and is doing something to treat their illness. Sometimes, that means they ask their doctor for antibiotics, even if antibiotics aren't the right thing to treat what they have.
In the past, and sometimes still today, doctors go ahead and prescribe antibiotics almost like a placebo. It's hard to say no to something a patient really wants, especially when it's likely to make them feel better—just because taking anything, and treating the problem, will make them feel better. But that is definitely not a good thing in the long term.
At KevinMD, family physician Dike Drummond offers some really nice advice for doctors who are struggling with how to make a patient feel better, but also want to avoid contributing to the growing antibiotic resistance problem. What I like best about Drummond's advice: It starts with empathy.
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If you have a major challenge working up some empathy one of two things is happening.
You are experiencing some level of burnout. Empathy is the first thing to go when You are not getting Your needs met. This is a whole different topic and “compassion fatigue” is a well known early sign of significant burnout.
There's a story making the rounds right now suggesting that the use of hair relaxers—products that are used more often by African American women than women of other ethnicities—might cause uterine fibroids—a painful condition experienced more often by African American women than women of other ethnicities.
Nobody really knows why African American women seem to be more prone to uterine fibroids, and, on the surface at least, this connection seems like it might make sense. Relaxers and other products contain hormones and chemicals that act like hormones. So, maybe, those things are getting absorbed into the body and leading to the growth of fibroids.
Trouble is: That's just speculation. And the evidence used to back it up is pretty flimsy. The study this story is based on looks at nothing but broad correlations: African American women have more fibroids and African American women use more of these hair care products. That's a problem, because broad correlations can be really, really misleading.
At The Urban Scientist blog, Danielle Lee (a scientist who has experience with both fibroids and hair relaxers) talks about why the "evidence" being presented in this case isn't even close to the same thing as "proof".
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Parabens and phthalates can do some funky things. (I don’t trust these chemicals.) They are problematic and should be evaluated for safety, especially by the US Food and Drug Administration. Parabens can be an estrogen mimic – but only slightly it seems. But it’s everywhere – not just in Black hair care products like shampoos and perms.
The Body Mass Index is a popular way to measure and assess whether someone is overweight or underweight. Basically, it's just your weight divided by your height. BMI is a simple system, but it does have some flaws. Over at the Obesity Panacea blog, Peter Janiszewski (who has a Ph.D. in exercise physiology) has a nice post explaining why BMI is sometimes useful, and also why it's not a great measurement of individual health.
Right now, I bet you're chomping at the bit with, "Yeah! The BMI doesn't distinguish between fat and muscle!" And you're right. It doesn't. A simple BMI measurement would tell you that The Rock is no different than an out-of-shape couch potato of the same height and weight. Obviously, that's a flaw in the system. But it's not the most important flaw, Janiszewki argues. In fact, he says, this well-known problem with BMI is the easiest one to work around. A simple visual check can tell your doctor whether your high BMI is due to excess muscle or excess fat.
The real problems with BMI, he says, are a lot more complicated. For one thing, the system doesn't distinguish between very real differences in health outcomes for different body types. "Pears" and "Apples" might have the same BMI, but with opposite health results. Even more troubling: You can change your lifestyle, and become objectively healthier, and your BMI might not budge.
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This is particularly so if you adopt a physically active lifestyle, along with a balanced diet, but are not necessarily cutting a whole lot of calories.
The Centers for Disease Control and Prevention, and the World Health Organization, say that H5N1 bird flu kills some 60% of the human beings it manages to infect. Basically, it hasn't infected many people—because it can't be spread from person to person—but most of the people it does infect die.
But this might not be the full story.
After I posted a summary of the current controversies surrounding H5N1 research, I got an interesting email from Vincent Racaniello, a professor of microbiology at Columbia University Medical Center. Racaniello points out that the 60% death rate statistics are based on people who show up at hospitals with serious symptoms of infection. So far, there've only been about 600 cases. And, yes, about 60% of them have died.
However, they don't necessarily represent everybody who has contracted H5N1.
A death rate is only as good as statistics on the rate of infection. If you've got an inaccurate count of the number of people infected, your death rate is going to be wrong. And there's some evidence that might be the case with H5N1.
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In a recent study of rural Thai villagers, sera from 800 individuals were collected and analyzed for antibodies against several avian influenza viruses, including H5N1, by hemagglutination-inhibition and neutralization assays. The results indicate that 73 participants (9.1%) had antibody titers against one of two different H5N1 strains. The authors conclude that ‘people in rural central Thailand may have experienced subclinical avian influenza virus infections’. A subclinical infection is one without apparent signs of illness.
We recently ran a guest post by Seth Roberts, detailing the case against tonsillectomies as a regularly prescribed treatment for sore throats. I was able to read Roberts' post before it went up here, and comment on it. And Roberts made several changes to the post, which I had suggested, before it ran.
In general, I'm a big fan of basing medical treatment on evidence, rather than conjecture, tradition, or mythology. And, while I have a big problem with woo-woo (shorthand for attempts at medical treatment that are based primarily on conjecture, tradition, and mythology), I do think it's important to point out that woo-woo doesn't always come from hippies. Local doctors don't always follow the evidence, either. In fact, that's one big reason why "evidence-based medicine" has to be called that, rather than just medicine. So while I didn't agree with everything Roberts had to say, I thought his key point—tonsillectomy as a treatment for sore throats isn't actually strongly supported by evidence—was a valuable one.
That said, I R NOT A MEDICAL EXPERT. And neither is Roberts. Steven Novella, however, is a medical doctor and a clinical researcher. He has a very good blog post up that points out some important flaws in Roberts post. Here's the gist of what he has to say: Roberts seems to have misunderstood some of the studies he linked to, and assigned too much importance to others. "Evidence" can mean a range of different things. Some evidence is better than others. Read the rest
The New York Times has a fascinating story about the current state of the science on weight loss, including the results of one recent (albeit small) study that suggests that the human body responds to weight loss by actively trying to regain weight—a finding that could help explain why it's so difficult to maintain significant weight loss, even when you are able to shed pounds. Read the rest
Over the years, I've been really impressed with the stuff I've heard about microfinancng charities like KIVA. The idea of helping people in developing countries launch and support small businesses, changing their lives and the lives of their children, makes a lot of sense. And the personal stories that go with microfinancing are pretty appealing.
I'm starting to re-think my opinions on microfinancing, however, after reading some of the research done by GiveWell.org, an organization that casts an evidence-based eye on what different charities do and whether they actually get the results they claim.
It's not that microfinancing is bad, per se, GiveWell says. It's just that the system doesn't measure up to the hype. And if you've got a limited amount of money to spend on helping other people, there might be more effective ways to do it that produce more bang for your buck.
GiveWell has written a ton on this, but I'd recommend starting with a blog post of theirs from a couple of years ago called 6 Myths About Microfinance Charities that Donors Can Live Without. This piece provides a succinct breakdown of what questions you should be asking about microfinance charities, and provides lots and lots of links for deeper digging. The myth that surprised me the most:
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Myth #6: microfinance works because of (a) the innovative “group lending” method; (b) targeting of women, who use loans more productively than men; (c) targeting of the poorest of the poor, who benefit most from loans.
Reality: all three of these claims are often repeated but (as far as we can tell) never backed up.
The casual and close-range use of pepper spray on nonviolent protesters: It's not just morally bankrupt, it's also not evidence based!
Judy Stone is a doctor, infectious disease specialist, and the author of a book on how to properly conduct clinical research. She's got a guest post on Scientific American blog network looking at the scientific research that's been done to document the effects and safety of pepper spray, and how to treat exposure to pepper spray.
Shorter version: The evidence basis behind the use of pepper spray, especially in the sort of contexts one is actually likely to encounter in the real world, is woefully limited. (It's a lot like tasers that way. In both cases, the research that does exist has mostly been done using physically fit, healthy, adult subjects who are not emotionally or physically distressed in any way at the moment they are hit. They're also being hit using manufacturer recommended dosages and distances of application. Real-world data suggests there's a MASSIVE difference between the effects of that sort of scenario and, say, a terrified teenager being shot in the face at point-blank range. Or an old woman who has been walking quickly, trying to get away from police. Just to throw some hypotheticals out there.) Meanwhile, the evidence that does exist strongly suggests that police forces are currently using pepper spray in ways that are inappropriate and unsafe. Evidence. Not opinion.
Also: Liquid antacids seem to be the best way to alleviate the effects of pepper spray. Read the rest