Monday, May 18, 2009

Face Masks For Flu

I've read several criticisms lately of wearing face masks to protect against the swine flu.  They explain that influenza germs are small enough to pass through face masks and therefore the masks are useless.  

I disagree.  

No, I'm not disputing the size of the virus or the porousness of the face masks.  I disagree that the only benefit of face masks is stopping airborne germs.

Influenzas, colds, and lots of other disease are contagious through tiny droplets of euphemistic water.  Really it's droplets of spit or snot, but water is much nicer to talk about.  Lots of these water droplets are expelled when people sneeze and cough and a few when people talk and yawn.  Even though these germ filled water droplets are usually so tiny they are invisible and even though they fly through the air, a disease that can be transmitted this way is not really airborne.  Each droplet is a lovely wet microcosm that can sustain germs that couldn't live in plain, dry air.  Droplets are big enough to hold colonies of germs that are too big and too heavy to float in the air.  A truly airborne virus can float in the air like a dust mote and can exist outside of a water droplet.  

Face masks don't stop airborne germs but they do stop germ filled water droplets.  So either swine flu is not airborne today and face masks will stop its transmission or it is airborne and face masks will make it less contagious by stopping those germs in water droplets.

The other thing face masks do is change habits.  They stop people from biting their nails and rubbing their nose.  They stop people from coughing into their hand just before turning a doorknob or pushing an elevator button.

  


Monday, March 23, 2009

Why I believe in evolution

I believe in evolution for the same reason I believe in the germ theory of disease or that atoms are made of electrons, protons, and neutrons; it's basic science.  

Like all basic science there are reams of direct evidence for evolution.  One of the beautiful things about science is that I don't have to rely on an authority figure to tell me "There's plenty of evidence."  I can verify the evidence and reasoning myself.  I can start by picking up a textbook or two and learning the basics.  I can go to museums and see some of the evidence for myself.  I can read about current experiments in the popular press that rely on that basic science.  I can make my own observations and if I'm ambitious I can do my own experiments.

For example, there's a local weed that grows short in neighborhoods but long in the park.  If I mow my front and back yard to different heights (change the selective pressure), will that weed respond?    

The Texas school board is voting on whether to change the biology curriculum to cast doubt on evolution.  This kind of nonsense frustrates me.  

I am sad that scientists and science educators have to spend so much time trying to explain basic science to people who perceive controversy, gaps, or weakness in it.  I am sad that because of the way the textbook market works changes in a religious, anti-intellectual state like Texas can effect science classes in the rest of the country.  I am irritated that members of a school board either know so little science or choose to believe so little science that this change has a chance of passing.  I am irritated that a religious agenda* is interfering with public schools.

*Religion is the only reason to be actively against evolution while ignoring quarks, F=ma, and cholesterol.  

Mostly I am sad and irritated that a group of grownups who are ignorant about science are trying to keep the next generation ignorant about science.

Wednesday, March 18, 2009

Life begins at conception. So what?

Many of the anti abortion people in the media say that life begins at conception and that therefore abortion is murder.  I think that's a lousy argument.  

To be clear, I am pro choice so I disagree with their conclusion.  But I don't think life is special. 

Most things we eat were once alive.  Salt is a rock and was never alive.  A lot of fruit can be eaten without killing the plant it came from.  But every time you eat a carrot, a plant was killed for you.  Following the form of the anti abortionists' argument, that carrot plant was murdered for you.  

Every time you take antibiotics for an infection or use vinegar on a cutting board you kill things that had been alive.

I don't mourn when I bleed, even though blood cells that share my DNA die.  Nor do I morn when I give a blood sample to get my cholesterol checked.  

So arguing that abortion is murder because life begins at conception is hypocritical even for anti abortionists who are vegetarian and don't kill spiders.

Sunday, January 18, 2009

Instructions Don't Cover All Contingencies

Most of Daughter 0.5's toys have specific, gentle cleaning instructions. "Don't immerse," they say. "Surface clean only," they say.

However, they don't say how to clean off copious amounts of spit up which is the consistency of pudding and which was generated while Daughter 0.5 was enthusiastically chewing on the toy.

Thursday, January 15, 2009

Does Caffeine Fuel Hallucinations?

A friend sent me a link to Drink coffee, see dead people which looks at a study which "quizzed 200 students on their caffeine intake and found those with the highest consumption were also more prone to report seeing, or hearing, things that were not there." The article implied that either increased caffeine consumption or the increase in stress hormone (cortisol) caused by caffeine caused the increase in hallucinations. It allowed that one alternate explanation might be that people who had more hallucinations used caffeine to deal with them.

Let me start with medical facts that go against conventional wisdom before picking on the article. There's an incorrect stereotype that someone who sees things or hears things is unusual and has serious problems. Hallucinations are not rare, not certain indicators of mental illness, and rarely as immersive as seen in TV dramas. A lot of sane and normal people very occasionally think they hear someone calling their name when no one's there, or hear a snatch of music when none is playing. A standard symptom of serious fatigue is to see little black dots moving at the edge of one's vision. It's common to interpret a vague shape out of the corner of one's eye as a person.

Even a good article on a scientific study is less useful than looking at the study itself and its data. Plus media is always biased. Even if an article avoids leaning left or right, avoids favoring either the outlandish or the traditional, it is still biased towards being interesting. Writers (and yes, I am feeling self-conscious as I write this) select interesting topics and then try to describe them in an interesting manner. It is entirely possibly (and hopefully likely) that the study only reported the correlation between caffeine and self-reported hallucinations and avoided drawing unsupported conclusions, but that's only mildly interesting to a small group of people. The title of the article "Drink coffee, see dead people" is catchy and the implication is weird and interesting.

There's a difference between perception and interpretation. The fatigue symptom of moving black dots can be interpreted as seeing ants on one's desk. The article says that participants were "sensing the presence of dead people." I'd like to know the specifics. Did they feel a crawling or cold sensation on the backs of their necks? Did they hear a dead person's voice? Did they see a human shape out of the corner of their eye and assume it was a dead person?

The article gives a nod to the logical truth that correlation does not indicate causation by mentioning that hallucinations might increase caffeine consumption instead of the other way around. But it doesn't mention the possibility of a common cause. Lack of sleep and lack of food are known to increase hallucinations. Do you suppose that students with the highest caffeine intake are well-rested and haven't skipped any meals lately? Me neither. I'd like to see a follow up study that controls for sleep habits and diet.

The article mentions "a daily equivalent of seven cups of instant coffee". Flippantly, I'd like to see the data divided by type of coffee; instant versus french press or espresso. I have a completely unsupported belief that coffee connoisseurs understand their sensory input better than those who drink instant. Plus we're smarter.

Monday, November 10, 2008

Baby Monitors Don't Monitor Just The Baby

I left Husband asleep in our bed and Daughter 0.1 asleep in her crib (which is in our bedroom) to do some online shopping and catch up on LOLcats when I heard this horrible noise through the baby monitor. I rushed to the crib worrying I'd find Daughter 0.1 coughing hard to keep from choking or vomiting worse than she ever has in her short life.

Instead I find her squinting with her hands in front of her face and body language that clearly said "Mom, I was sleeping. Why'd you turn on the light?"

Surprised, I stopped and listened. The shower was running. I walked into the bathroom to catch my husband sneezing. And sneezing again.

So through a closed door, over the noise of the shower, the baby monitor picked up my husband's sneezing fit while our baby was sleeping peacefully.

Thursday, October 30, 2008

You'll Understand When...

A friend reminded me of the phrase "You'll understand when you have children."

When I was young I disliked it as a non-answer. People used it instead of trying to explain something.

When I was older but still single I was uncomfortable with the assumption that I would or should have children. (Aforementioned friend doesn't like that assumption either.)

Now that I'm a parent, I think that "You'll understand when you have children" is a short, thoughtless way of saying "If you had been dealing with a baby for hours, days, and weeks while extremely sleep-deprived you would be able to recognize certain behaviors and do certain tasks instinctively, too."

There's also the emotional attachment to the baby. Some of that is hormones. Before labor and delivery I was fond of the autonomous being who lived in my abdomen. Immediately after delivery, I thought she was adorable, loved her, and strongly wanted to protect her and keep her close. That was a sudden emotional change that coincided with a sudden dose of hormones.

So if you're a parent and you have the urge to tell someone, "You'll understand when you have children." consider starting with, "It's difficult to explain, but let me try." instead.

Monday, October 20, 2008

Why do people believe weird things?

Many people believe many things that aren't true, or that aren't provably true. Whether it's something to cure the common cold, cause bad luck, or guaranteed to make money fast there are many who buy it, avoid it, invest in it, and tell their friends how it worked for them.

There are many websites debunking such things or embracing science that shows what is true or false. Skepchick and Snopes are two I like.

But today I wonder why people believe weird things.

People develop superstitions easily.
I had a friend years ago who wore the same sweatshirt a few times while watching his favorite sports team win on TV. He developed a belief that he had to wear that sweatshirt during a game in order for the team to win. This pattern is very common. The same thing happens a few times in a row and people believe it is "always" true. Once the superstition is established people remember the events that reinforce it and discount the events that don't. Have you ever thought or said something like:
- "This traffic light is always red."
- "This line at the grocery store is always faster."
- "My gate at the airport never changes."
- "I never loose my keys."
- "I catch colds more than most people."
- "It always rains on holidays."
Chances are the light, line, gate, etc. is random and your perception is wrong. The only way to know is to carefully track the events so you have solid data to counteract your selective memory.

The human brain is great at finding patterns.
It's so good at finding patterns that it finds them where they don't exist. Have you ever found shapes in clouds? I used to do that as a child; lie on the grass and watch the clouds go by and call out ones that looked like a ship or a bunny. Of course the similarity is only coincidence, there is no mechanism causing a certain cloud to specifically resemble a rabbit. Evolution clearly favored the ability to find every real pattern (and some false ones) over avoiding false patterns (and missing some real ones). I don't know why recognizing patterns is so beneficial but I'm sure there's an evolutionary biologist or evolutionary psychologist with a good hypothesis.

Logical fallacies are difficult.
Okay, maybe they're not difficult to understand while reading about them or during a formal debate, but most people don't internalize that understanding well enough to recognize logical fallacies at other times. Two common ones are:
- "Post hoc ergo propter hoc." That's Latin for "After this therefore because of this." The fallacy is thinking that since B happened after A, B was caused by A. I think this fallacy explains why so many people believe vaccines cause autism. The age when autism symptoms usually first show up is after the MMR vaccine is routinely given. So when those poor parents hear this horrible diagnosis the most recent event in their child's life was that vaccine. But believing that causal relationship makes as much sense as believing that breakfast causes lunch or that fifth grade causes puberty.
- "Correlation does not indicate causation." Lots of things increase or decrease at the same time, but that's mostly coincidence. Over time the population increases and the year number increases. That doesn't mean that incrementing the year makes the population go up. Further, if we decide next year is year 10,000 and then we'll count backwards every year, that won't make the population go down. But it's easy for someone to assume causation when they see a correlation, and easier when there's an official looking line graph.

People tend to believe other people.
Humans are social. We thrive when get along with each other and learn from each other. So when a friend says "This supplement cured my cold" or "This stock is certain to go up" people tend to believe it. It's more social, easier, and more pleasant to trust one's friends (or newscasters, priests, aerobic instructors, etc.) than to do one's own analysis. So once an unproven or incorrect idea is out there it tends to spread.

Most people don't trust the scientific method.
The scientific method is the best tool we have to understand our universe. Sadly, most people picture science as the combination of books full of facts and authority figures who call themselves scientists. Most people don't know (or don't think about) the process that finds all those facts. Many people trust the Bible more than science texts and clergy more than scientists...and they think these things are similar.

So there are reasons why people believe various sorts of woo; understandable, human reasons. But I think it is responsible to question one's beliefs, assess the evidence, and discard unsubstantiated beliefs.

Friday, October 17, 2008

Motherhood Has Turned Down My Gross-O-Meter

I used to think that urine and feces were categorically gross. My own was acceptable when it went directly into the toilet and was flushed promptly and successfully. Anything else was gross.

Feel free to stop reading now. Really.

[If you know how to do a cut, jump, fold, "Read More", or whatever it's called in Blogger, please leave a comment and let me know how. I can't seem to figure it out and I have yet to find anything about it in Blogger's help articles.]





Daughter 0.1 spit up a lot early this afternoon. Repeatedly. Since I was walking around the house holding her at the time, she spat up on my shoulder, down my back, on the back of my right calf, and on the floor. When she seemed to be done I figured I'd change my shirt and give her a quick bath.

Did you read that? "Quick bath." That was foreshadowing.

Bath time always includes some risk of a mess because the diaper has to come off before the baby goes into the bath. So far we've been lucky with the naked baby transportation.

This time she peed on me. Since I was holding her upright against my chest she peed on my shirt and shorts. For a small creature she can let loose a lot of urine. My pre-motherhood reaction to being peed on would have been quite vocal and I would have gotten the pee off me before doing anything else. Instead, I finished putting the baby in the bath* and thought about how I would pick up my clean baby after the bath without getting her pee back on her.

*Her bath is in the laundry room sink for now. She fits, it's more comfortable than bending over a tub, and it has a vegetable sprayer.**

**Clearly these aren't foot notes since they're in the middle, but I'm not sure what to call them. Asterisk-ized digressions?

So there I am, half-soaked with baby pee, holding the baby in one arm so I can wash her bottom when she starts to poo. And poo. And poo some more.

For the first few weeks, babies poo often. The tracking sheet from the hospital says 4 to 12 times a day. But once their digestion matures enough breast-fed babies poo much less often since they absorb most of what they take in. One baby health book says not to worry if they only poo once a week. Today is Friday and until this afternoon Daugher0.1 hadn't pooed since Monday. I don't think she was absorbing; I think she was saving it up.

She's still pooing in the sink and I'm using the vegetable sprayer in one hand to wash the poo down the drain and off her feet while I'm holding her partly upright with the other hand. I'm not saying "EWWW!", I'm not thinking "This is gross." Instead I'm thinking, "My arm's getting tired. I hope she's done soon." After some more pooing I start to think it's a good thing she's pooing in the sink because this much wouldn't fit in a diaper and a leaky diaper is a bad, surprising kind of mess.

Becoming a mother has drastically increased my tolerance for things that come out of babies.

Friday, September 26, 2008

Wiki Worldflicks: Images and Maps

I was looking for a picture of a waterfall and happened across an image wiki build on Google maps.

http://wiki.worldflicks.org

I had a hard time navigating to a specific place, but The Smithsonian is a good place to start.

Have fun!