Archive for the ‘General’ Category.

Should I Pay Off Student Loans or Put The Money In the Stock Market?

Hypothetically, if you had three student loans totaling about $100,000 at different interest rates… say $3%, 5%, and 6%, would you push to pay them off or invest the “extra” money in the stock market?

My first thought was that the stock market generally pays 7% interest over inflation so I should pay down the 6% loan and put all the rest of the money into the stock market, but now I’m second-guessing myself. Thoughts?

Of course, first priority is to make a rainy day fund and pay into a matching 401(k).

I found this crazy-cool chart that shows the S&P 500 doing something like 3% better than inflation over long periods of time. (via) so maybe I should pay off all the student loans. My investing average seems to be waay better than 3% but when I look at that crazy-cool chart, I can see that I’ve been investing in a big bubble for a long time.

Blargh. Why can’t it be easy to make lots of money without doing any work? Oh wait, yeah.

Figured It Out!

There was this awful noise that I’d sometimes hear in my room at school. It sounded like a machine in the walls suddenly turning on. Sometimes for a half a second, sometimes for a minute. On and off, on and off! It’d come on a bit more around 11am or so so I thought it might be related to kids going to the nearby bathroom. When it was happening and I had the opportunity, I’d run around the building looking for the source. It wasn’t the air conditioning, wasn’t the bathrooms, wasn’t the heaters, wasn’t the neighboring classrooms playing with power tools. I talked to the school custodian, to the neighboring teachers. But they all thought I was mad. I wasn’t mad! I wasn’t! I swear it!


Then, a few days ago, more than a YEAR after first noticing the sound, I found it! A water hammer in the sink of the classroom two doors down. So simple! When the kids were cleaning up from morning work, they’d turn on the water. Curiously, it was quieter in the room with the offending sink than in mine.

I got the most joy when Ms. S. the teacher one door down told me how for the last DECADE she was explaining-away that horrible sound to her students. We were both beaming!


I went to the custodian and explained what was going on. We wrote up a work order for the plumber together. And 3 days later, with one gentle turn of a wrench, the problem dissolved into the mists!


1 mile

My in-laws’ two homes are each about 1 mile away from the flames of the Kincaid fire in Santa Rosa. Please send good wishes!

Moderate Humidity Decreases Infection Rates

TL;DNR: Keeping the humidity at 40-60% dramatically decreases airborne infection rates!

Here are snippets from an article in Forbes, shown to me by Winnie Chen.

Oct 17, 2019, 09:30am
This Inexpensive Action Lowers Hospital Infections And Protects Against Flu Season
Leah Binder

“Harvard Medical School graduate and lecturer, Stephanie Taylor” heads this research…

“The one factor most associated with infection was (drum roll): dry air.”

“Taylor finds one of the most interesting studies from a team at the Mayo Clinic, which humidified half of the classrooms in a preschool and left the other half alone over three months during the winter. Influenza-related absenteeism in the humidified classrooms was two-thirds lower than in the standard classrooms—a dramatic difference.”

“They used to assume the microbes in desiccated droplets were dead, but advances in the past several years changed that thinking.”

Machine Learning Hand Gender

In looking up hand research for work, I came across this super-cool machine learning article. In brief: a computer can read an X-Ray and tell if a person is a boy or girl really accurately and (at least some) doctors can’t! Maybe by paying attention to what the computer sees, doctors can figure out how to determine the gender of the hand in the X-ray.

Despite the well-established impact of sex and sex hormones on bone structure and density, there has been limited description of sexual dimorphism in the hand and wrist in the literature. We developed a deep convolutional neural network (CNN) model to predict sex based on hand radiographs of children and adults aged between 5 and 70 years. Of the 1531 radiographs tested, the algorithm predicted sex correctly in 95.9% (κ = 0.92) of the cases. Two human radiologists achieved 58% (κ = 0.15) and 46% (κ = − 0.07) accuracy. The class activation maps (CAM) showed that the model mostly focused on the 2nd and 3rd metacarpal base or thumb sesamoid in women, and distal radioulnar joint, distal radial physis and epiphysis, or 3rd metacarpophalangeal joint in men. The radiologists reviewed 70 cases (35 females and 35 males) labeled with sex along with heat maps generated by CAM, but they could not find any patterns that distinguish the two sexes. A small sample of patients (n = 44) with sexual developmental disorders or transgender identity was selected for a preliminary exploration of application of the model. The model prediction agreed with phenotypic sex in only 77.8% (κ = 0.54) of these cases. To the best of our knowledge, this is the first study that demonstrated a machine learning model to perform a task in which human experts could not fulfill.


Looking for Noisy-environment speech recognition microphone

Please help me find a good noisy-environment speech recognition microphone. I have students that want to use speech-to-text in their classroom, the microphone should pick up the student’s voice but not stray voices in the room. Best if it’s on a headset.