Later On

A blog written for those whose interests more or less match mine.

Archive for January 9th, 2018

Yet Another North Carolina Voting Law Has Been Struck Down

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Kevin Drum describes how life is in some states. Please read.

Written by LeisureGuy

9 January 2018 at 7:07 pm

Posted in Election, GOP, Government, Law

In Praise of Simple Problems

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Kevin Hartnett writes in Quanta:

Most of the important discoveries in mathematics take place after decades or centuries of effort. If you want to attack the biggest problems, you’ll need to master a lot of highly technical material before you can even begin to say something new.

Such questions don’t interest Richard Schwartz. He likes problems he can read about today and start solving tomorrow — simple problems, fun problems, problems that have the aspect of a carnival game: Step right up and see what you can do with this one! It’s an unusual disposition among research mathematicians. Schwartz embraces it completely. “I don’t think I have a mature attitude towards math,” he said.

Yet none of this is to say that Schwartz is anything but a serious and accomplished mathematician. He is. He received his doctorate at Princeton University under the mentorship of Bill Thurston, one of the most important mathematicians of the last half-century. He is now a tenured professor at Brown University whose most important work has taken place in the field of dynamics, which studies the long-run behavior of iterative processes, like a billiard ball ricocheting on a frictionless table. In 2008 he proved that every triangle with angles all less than 100 degrees contains at least one periodic billiard path — a repeating path that a ball will trace and retrace forever.

Schwartz uses computer experiments in much of his work — he’s on the vanguard in that respect. As he explains, computers complement human mathematical thought in several ways: They draw out patterns that provide hints which lead to proofs that might not have been apparent to the mind alone.

Quanta Magazine spoke with Schwartz about his taste for simple problems, what he called the “miracles” of mathematics, and his upcoming math book for kids about infinity. An edited and condensed version of those conversations follows.

What do you like about mathematics?

I like all kinds of things about it. The first thing is I like the fact that it works, somehow. I like the fact that it’s procedural, and there’s a method to it so you can make progress. I like that you can get to the bottom of questions, unlike, say, politics or religion where you can just talk for years with people and no one will change the other’s opinion.

I also just like shapes and numbers. I’ve always had a love for these kinds of things for some primitive reason I can’t quite explain. Then, I like the intellectual challenge. I like solving problems, trying to solve problems that people can’t solve. There’s kind of a mountain-climbing aspect to it. Finally, I like the beauty of pure mathematics, much in the same way someone might like a work of art.

You said you like simple problems. Why?

I feel if it’s a simple problem that hasn’t been solved, it probably has some kind of hidden depth to it. In other words, there’s something missing in human knowledge that prevents people from solving the problem.

The second thing is that I like doing computer experiments, and so I feel that sometimes I have a chance of making progress. The modern computer is a new tool, and I think of these simple things as excuses for data gathering. Like, I’m just going to program the computer and run some experiments and see if I can turn up some hidden patterns that nobody else had seen just because they hadn’t yet done these experiments.

The third thing, which maybe sounds a little silly, is that the simple problems I like don’t require much background to get into them. I like things where I can just start working. I’m impatient. If I hear about some conjecture in some fancy area of math, I’m lazy about it. I don’t feel like spending six months reading the literature until I get to the point where I’m ready to attack this problem. I like to just get my hands dirty and start right away.

What’s an example of a simple problem?

Continue reading.

Written by LeisureGuy

9 January 2018 at 5:04 pm

Posted in Math

You think you’ve read (or written) a tough letter? HERE’s a really letter.

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Although I do like the phrase Nick Fotos (long-ago Annapolis friend) favored:”If you fail to cease and desist, I will take such steps as will amaze you.” Still, I think this one is tougher (PDF).

Written by LeisureGuy

9 January 2018 at 4:48 pm

Black bean chili with chicken (3 points per serving)

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Serving size is 1 cup. Recipe makes about 4 servings.

1 1/2 tablespoons olive oil
2 anchovy fillets, minced
2 large white onions, chopped
6-8 cloves garlic, minced
2 cups cooked black beans, drained (don’t use canned beans; cook 1 cup dried beans)
[2-3 jalapeño peppers, chopped including ribs and seeds – if you want spice. Can use Serrano as well.]
1 yellow bell pepper, chopped
1 red bell pepper, chopped
1 tablespoon ground ancho
1 1/2 tablespoons ground cumin
1 tablespoon smoked paprika
2 tablespoons Mexican oregano
1 tablespoon thyme
1 tablespoon ground coriander
14.5-oz can diced tomatoes
10-oz can mild green chilis, chopped (if you can’t find them, you can use chopped green bell pepper and/or 3 Anaheim peppers)
12 cherry tomatoes, halved (I like the yellow ones, but red works fine)
1 tablespoon soy sauce
1 tablespoon rice vinegar
1 tablespoon liquid smoke
1 1/2 tablespoons black pepper
2 teaspoons salt
1.5 tablespoons cocoa powder
1 packet Starbucks instant coffee

1-2 poached chicken breasts, cut into chunks (see this post for best way to poach chicken breasts)

Mince garlic right away so it can rest for at least 10 minutes before cooking

Heat oil and sauté onions and minced anchovy fillets until onions are soft and translucent and golden. Add spices and then black bean and chopped bell peppers (and Anaheim peppers if using). Sauté for a few minutes, stirring frequently. Also, if you can’t get canned green chiles, sauté a chopped green bell pepper and (if using) chopped Anaheim peppers along with the onion.

BTW, buy whole green chiles, not diced: the diced ones tend to lose their structure and become goo.

After that has sautéd for a while, add remaining ingredients, cover, and simmer 30 minutes.

1 cup of this chili = 2 Weight Watcher points.

1/4 cup shredded cheddar (or equivalent) = 4 WW points. Just FYI.

If you use a square of unsweetened baking chocolate instead of the cocoa powder, you get a 5-point dinner rather than a 3-point dinner.

Written by LeisureGuy

9 January 2018 at 4:09 pm

Posted in Food, Low carb, Recipes

Canadian Research Adds to Worry Over an Environmental Threat the Pentagon Has Downplayed for Decades

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Abrahm Lustgarten reports in ProPublica:

New research by Canadian scientists into the spread of a chemical commonly used in military explosives has confirmed some of the worst fears of U.S. environmental regulators tracking the threat posed by the Pentagon’s handling of its munitions in this country.

The Canadian research analyzed soil and water samples at nine sites where military explosives were detonated between 1990 and 2014, and came up with data about where and in what concentrations the explosive compound known as RDX, a possible human carcinogen, had turned up. Calling RDX “an internationally known problem,” which “has led to an international warning on possible soil, surface water, and groundwater contamination on military training sites,” the research described with actual measurements how RDX floats on the wind and seeps through soils into water supplies.

The researchers took water samples from groundwater at the explosives sites and found that in 26 out of 36 samples, the RDX that had made its way into aquifers exceeded levels considered safe. As a result, the researchers suggest that the data can be used to model RDX contamination at any site where munitions are routinely detonated, and for the first time, give environmental experts a way to quantify how much of it is spreading into surrounding communities.

RDX was considered a major military breakthrough when it was first developed for large-scale use on the eve of World War II, and to this day it remains a staple of the U.S. military’s war-making abilities, used in bombs, missiles and other weapons. And for decades, the Pentagon has known about RDX’s potential health and environmental threat. But the Pentagon has long maintained that the risk is not great, and it has both financed research and flexed its political muscle to have its view prevail. Most recently, the Pentagon has waged an intense fight to not have the U.S. Environmental Protection Agency upgrade its classification of RDX’s health threat, a move that could expose the Department of Defense to billions of added dollars in cleanup costs.

At a minimum, the Canadian research — published Nov. 17 in the Journal of Environmental Quality — will add to the store of knowledge about RDX contamination. The research found that while the highest concentrations of RDX remained in a ring around the sites where munitions had exploded, pieces of explosive, perhaps as large as a centimeter, were carried on the wind and later settled in the soil. Surface and groundwater samples showed that the RDX ultimately did not quickly dissolve or degrade as it sank deeper into the earth, where it usually was carried into water supplies.

Harry Craig, one of the Environmental Protection Agency’s foremost experts on explosives contamination, has described RDX as the single greatest problem the U.S. faces when it comes to cleaning up thousands of toxic munitions sites across the country. In an email to agency colleagues, Craig described the Canadian research as both novel and useful.

ProPublica reported on the history of RDX and the Department of Defense’s long-standing campaign to minimize its risks and fight EPA regulation in December. RDX has been discovered at dozens of U.S. defense sites, and increasingly in public drinking water supplies around them.  After early research by the U.S. Army determined that RDX was likely responsible for cancerous tumors in rats and mice, the Department of Defense has produced dozens of reports portraying RDX as more benign. . .

Continue reading.

Written by LeisureGuy

9 January 2018 at 3:00 pm

Best tea cosy I’ve found so far

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I now routinely brew up a pot of tea (currently Assam alone or Keemun/Assam mix), and naturally enough I wanted a tea cosy so the pot would stay hot. This one is the best I’ve tried. I was recommended by The Younger Daughter, a long-time tea drinker.

It opens into two halves, held together by the base on which the teapot sits. The bow is merely decoration, not functional. The two halves are wrapped up and around the teapot and held in place by an elastic band. The handle and spout emerge from between the two halves.

It works quite well. Highly recommended for tea drinkers.

BTW, on a cold rainy afternoon I had a second pot of tea and really had trouble sleeping. So now in the afternoon I drink herbal teas. My favorite now is Stash Wild Raspberry and Hibiscus. No effect on sleep, so far as I can tell.

Written by LeisureGuy

9 January 2018 at 10:07 am

Posted in Daily life, Drinks

LA Shaving Soap Company and the Baili BR171

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I really like the fragrance of this shaving soap, probably in part due to the vanilla, but the eucalyptus and mint brighten the fragrance considerably. The Vie-Long horsehair brush (which I let soak while I shower) made a very nice lather, and the wonderful Baili BR171 did a superb job. This is definitely one of my favorite razors, and it’s only $6.

A splash of Royal Copenhagen aftershave from a little bottle I bought for travel, and the day begins.

Written by LeisureGuy

9 January 2018 at 9:15 am

Posted in Shaving

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