kitchen table math, the sequel: 4/29/12 - 5/6/12

Saturday, May 5, 2012

thinner, part 2

In the wake of my discovery re: weight and cognition, I've decided to harp on my vegans-are-thinner experience. Re-harp, that is.

AND SEE: thinner
AND: the Ed diet

arithmetic and the brain


Recent studies in human neuroimaging, primate neurophysiology, and developmental neuropsychology indicate that the human ability for arithmetic has a tangible cerebral substrate. The human intraparietal sulcus is systematically activated in all number tasks and could host a central amodal representation of quantity. Areas of the precentral and inferior prefrontal cortex also activate when subjects engage in mental calculation. A monkey analogue of these parieto-frontal regions has recently been identified, and a neuronal population code for number has been characterized. Finally, pathologies of this system, leading to acalculia in adults or to developmental dyscalculia in children, are beginning to be understood, thus paving the way for brain-oriented intervention studies.

Arithmetic and the brain.
Dehaene S, Molko N, Cohen L, Wilson AJ.
Curr Opin Neurobiol. 2004 Apr;14(2):218-24.

help desk

2 seats open; 5 candidates running; maybe 1600 people will vote. Two candidates are running as a slate, with posters around town saying "Two seats, two votes."

There will be some bullet-voting. No idea how much.

What's the fewest votes a candidate would need to win if the race is close?

good news from the state tests for once

Robert Pondiscio on Pineapplegate 

The kids interviewed in the Times seem to know exactly what's wrong with the pineapple item.

Friday, May 4, 2012

most Berkeley students do not know

Brad De Long:
How can they expect to survive in the modern world without knowing these things?
And why haven't they learned them?
To which I can only say: Brad DeLong has not been paying attention!

I've just started reading the comments. Calculators in grade school aren't faring well thus far.

From the first Comment:
The best students are great, but the quantitative reasoning skills of even the average student at a good university are worse than those of a typical waiter/waitress 40 years ago.

brain atrophy in teens with Type 2 diabetes

We also measured the brain, the hippocampus... What we found was that among the kids with Type 2  diabetes, their hippocampi are smaller in volume, very significantly. For those of you who work in Alzheimer's disease, the difference between the kids with Type 2 diabetes and the control kids [who were obese but did not have Type 2 diabetes] is about the same as that between a normal elderly and one with mild cognitive impairment. So the volume difference is around 12% So this is not a small, little thing. So what will happen to these children, whether we're actually seeing permanent damage or not, we don't know.

Their frontal lobe regions are also affected, and they have more overall brain atrophy than the control group. And remember, the control group was an obese control group.

Impact of Obesity and Metabolic Disease on Brain Structure and Function 5/5/11
Antonio Convit, M.D.
I haven't watched the entire lecture, but I gather that the reason he tells us to remember that the control group is obese is that we can also expect to see brain changes in obese teens who have not developed Type 2 diabetes, which would mean that the brains of teenagers with Type 2 diabetes are even more different from the brains of normal-weight adolescents.*

The lecture - the few minutes I've watched of it - is horrifying.

I had no idea.

*update (4/5/2012)

Right. Obesity in and of itself, without Type 2 diabetes, is linked to brain atrophy. Sounds like overweight may be as well, at least in people over 70.
They found that obese individuals [over age 70] had, on average, 8 percent less brain tissue than people of normal weight, while overweight people had 4 percent less tissue. According to Thompson, who is also a member of UCLA's Laboratory of Neuro Imaging, this is the first time anyone has established a link between being overweight and having what he describes as "severe brain degeneration."

"That's a big loss of tissue, and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer's and other diseases that attack the brain," he said. "But you can greatly reduce your risk for Alzheimer's if you can eat healthily and keep your weight under control."
btw, remember back when I was bugging everyone about vegan diets making you thin?

Well, they do. I adopted a vegan weight-loss diet in September 2009, lost 11 pounds, and have basically kept it off ever since -- without even being a vegan. I need to get back on track, but still: even part-time veganism makes you thinner than full-time non-veganism.

Monday, April 30, 2012

not your father's bell curve

Sticky wages in 2011:

The tall bar in the middle represents workers who had a wage increase of $0
People to the right of the bar had pay raises
People to the left of the bar had pay cuts
Why Has Wage Growth Stayed Strong?
By Mary Daly, Bart Hobijn, and Brian Lucking

I've been meaning to post this for a while now.

I find this chart fascinating. I have never, not once in my entire lifetime, seen a curve that looked like this -- although they must be out there.

Here's the San Francisco Fed write-up:
Researchers generally point to asymmetries in the distribution of observed wage changes among individual workers as evidence of nominal wage rigidities. Figure 2 plots an example of this type of wage change distribution in 2011. The dashed black line shows a symmetric normal distribution. The blue bars plot the actual distribution of nominal wages.

The figure’s most striking feature is the blue bar that spikes at zero, indicating the large number of workers who report no change in wages over a year. This spike stands out in the distribution of actual wage changes, suggesting that, rather than cutting pay [in line with reduced earnings], employers simply kept wages fixed over the year. This is supported by the large gap to the left of zero between the actual distribution of wage changes and the dashed black line representing the normal distribution. This gap suggests that the spike at zero is made up mostly of workers whose wages otherwise would have been cut.
Once you start thinking about sticky wages, you see them everywhere.

For instance, Ed and I were watching an episode of Friday Night Lights a couple of weekends back, and the story line, which spanned multiple episodes, revolved around budget cuts to the schools. First the cuts were rumored, then the cuts were announced, and then there was rending of clothes and tearing of hair and parents mobbing board meetings to demand that cuts happen to other people's programs, not theirs. (And, yes, this sequence of events does sound familiar).

It was high drama.

Teachers would be FIRED!

Football teams would be MERGED!

Fire and flood, death and despair!

Two years ago, right up to the moment I found out about  downward nominal wage rigidities over the business cycle, * this story line would have made perfect sense to me. Like everyone else on the planet (including pick-up farm workers and their employers in India, apparently), I simply took it as a given that people can be cut but wages can't. In hard times, fear and loss (and television drama) follow directly from this belief.

But once you know about the money illusion, a school budget crisis loses most of its oomph as dramatic premise. Watching the pandemonium onscreen, I was unmoved. I kept thinking, "How about a wage freeze? How about a furlough? How about a wage cut?"

"How about everyone sit down and do some arithmetic and, while you're at it, figure out that it's not like the Dillon School District is a family where the sole breadwinner just lost their** job. You've still got money coming in, you just don't have as much money coming in next year as you did this year. (Or, if Dillon is anything like Westchester County, you don't have as big an increase coming in next year as you did this year, but you've still got an increase.) So everyone's gonna have to make do with less, but nobody's gonna starve, not unless you insist on firing the young teachers so the old teachers don't have to take a cut."

No dice.

The story arc ends with teachers getting fired and football teams getting merged, and nobody says 'boo' about the possibility of 'shared sacrifice' and the like.

I realize that, in real life, employees do take freezes and furloughs to keep everyone on the job. But they don't do it often, as the chart reveals.

* I have now consumed so much macroeconomics that I can read formulations like downward nominal wage rigidities over the business cycle almost as fast as I can read twinkle, twinkle, little star.
**It pains me to write "the sole breadwinner just lost their job," as opposed to "the sole breadwinner just lost his job," but I think the time has come.

Direct Instruction in Grammar

From the study guide for the California Teachers of English Learners Teacher Certification Exam:
"Direct instruction in grammar and spelling has had disappointing effects on students' writing.  Teachers have not achieved much success with extensive error correction either.  The most successful teaching of language conventions has been the presentation of well-written materials.  A good reader becomes a good writer as the self editing process develops and good models are available.  A teacher is most likely to be successful if he/she keeps a variety of well-written and easily understood examples of both written and spoken English available to the students."

Study guide was prepared by and has no affiliation with the California Teacher Credentialing Dept. nor the testing companies that California uses.  The above quoted passage doesn't seem that far out of line from what I've seen presented in ed school classes.

Susan S on Facebook

One problem I had was with my special ed son. He is very "young" even though he's grown. He mostly likes coupons and anime, and kid stuff, so I never worried about him and rarely checked.

Well, I noticed one day that he had a couple of men that he barely knew that were his new "friends". They were friends of friends of friends, or so the story goes. He really didn't know them. Well, they were engaging him (trying to set up a meet) that was disturbing to me. He was uncomfortable, too, so he did unfriend them and refused to answer. But I was surprised that he had allowed them in.

If a photo gets tagged, you can get it untagged, but if it has gone out to a bunch of people, I don't think you can get it back. So, someone can have a picture of you that you have no control over, and then tag it and send it to many.

Another time, and I think this was Yahoo and not FB, I was alerted that a friend of mine had commented at some blog. It even showed me her comment. I asked her if she knew about it and she said no. We both had to change our privacy settings (and the rest of our family's) to stop it. Again, I think that was Yahoo.

Someone out there probably knows more than me, but those were just a few of my experiences.

Facebook rules

Terri W:
Do not post or say anything on any network, email, chat, text, website, WHATEVER unless you are willing for the whole world to see it.

For Facebook, I'd actually use a slightly different rule (borrowed from a friend who was going through a lot and who loved posting on Facebook): "Only good goes on Facebook." When I see my students getting into trouble, that's the rule they break.