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Old 2020-02-14, 20:49   #2696
masser's Avatar
Jul 2003

23348 Posts

Ugh. I'm certain that countless teachers have discovered the exact same approach. Most of them had the humility and sense not to squawk about such a near-triviality.

He even found out that a math teacher in Sudbury, Canada, named John Savage came up with a similar approach 30 years ago. An article by Mr. Savage in the journal The Mathematics Teacher in 1989 laid out almost the same procedure, although Dr. Loh filled in some nuances of logic in explaining why it works.

“I honestly can’t remember exactly where the eureka moment was,” Mr. Savage said in a phone interview. But it seemed to be an improvement over the usual way of teaching the subject.

He continued using that approach, as did some other teachers he knew. But the internet was still in its infancy, and the idea faded away.

“It never caught on,” Mr. Savage said. “Looking back on it, I should have pushed it a little more. I think it’s so much easier than the traditional way.”

Mr. Savage said he was excited to see the same idea revived 22 years after he had retired. “I was quite interested to read it now,” he said of Dr. Loh’s paper. “It’s quite interesting that he basically came up with the same idea.”
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Old 2020-02-14, 21:03   #2697
6809 > 6502
Uncwilly's Avatar
Aug 2003
101×103 Posts

7·1,087 Posts

Betelgeuses shenanigans just got weirder, only part of it is dimming
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Old 2020-02-14, 22:06   #2698
ewmayer's Avatar
Sep 2002
República de California

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Originally Posted by rogue View Post
It's near-criminal for articles such as this to omit mention of Kolmogorov's associated 1941 turbulent-microscale theory. Wikipedia describes the connection between the 2 scaling regimes:
Similar to the Kolmogorov microscales, which describe the smallest scales of turbulence before viscosity dominates; the Batchelor scale describes the smallest length scales of fluctuations in scalar concentration that can exist before being dominated by molecular diffusion. It is important to note that for Sc>1, which is common in many liquid flows, the Batchelor scale is small when compared to the Kolmogorov microscales. This means that scalar transport occurs at scales smaller than the smallest eddy size.
It's winking at us! "Hiya, sailor - looking for a shoulder to cry on?"

Last fiddled with by ewmayer on 2020-02-14 at 22:09
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Old 2020-02-16, 20:25   #2699
ewmayer's Avatar
Sep 2002
República de California

2·32·593 Posts

Scientists discover largest bacteria-eating virus. It blurs line between living and nonliving. | LiveScience
...the researchers searched through a DNA database that they created from samples they and their colleagues collected from nearly 30 different environments around the world, ranging from the guts of people and Alaskan moose to a South African bioreactor and a Tibetan hot spring, according to a statement.

From that DNA, they discovered 351 huge phages that had genomes four or more times larger than the average genome of phages. Among those was the largest phage found to date with a genome of 735,000 base pairs — the pairs of nucleotides that make up the rungs of the DNA molecule's "ladder" structure — or nearly 15 times larger than the average phage. (The human genome contains about 3 billion base pairs.)

These phages are "hybrids between what we think of as traditional viruses and traditional living organisms," such as bacteria and archaea, senior author Jill Banfield, a University of California, Berkeley, professor of Earth and planetary science and of environmental science, policy and management, said in the statement. This huge phages' genome is much larger than the genomes of many bacteria, according to the statement.

The authors found that many of the genes coded for proteins that are yet unknown to us. They found that the phages had a number of genes that are not typical of viruses but are typical of bacteria, according to the statement. Some of these genes are part of a system that bacteria use to fight viruses (and was later adapted by humans to edit genes, a technique called CRISPR-Cas9).

Scientists don't know for sure, but they think that once these phages inject their DNA into bacteria, the phages' own CRISPR system strengthens the CRISPR system of the bacteria. In that way, the combined CRISPR system could help to target other phages (getting rid of the competition).

What's more, they found that some of the phages had genes that coded for proteins necessary for the functioning of ribosomes — a cellular machine that translates genetic material into proteins (the proteins are the molecules that carry out DNA's instructions). These proteins aren't typically found in viruses, but they are found in bacteria and archaea, according to the statement.

Some of these newfound phages may also use the ribosomes in their bacteria host to make more copies of their own proteins, according to the statement.

"Typically, what separates life from nonlife is to have ribosomes and the ability to do translation; that is one of the major defining features that separate viruses and bacteria, nonlife and life," co-lead author Rohan Sachdeva, a research associate at UC Berkeley, said in the statement. "Some large phages have a lot of this translational machinery, so they are blurring the line a bit."

Last fiddled with by ewmayer on 2020-02-16 at 20:26
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Old 2020-02-19, 20:03   #2701
xilman's Avatar
May 2003
Down not across

2·47·103 Posts

I still use paper star maps on a night to night basis, despite the availability of alternatives on the interweb thingy which are in full colour and go much fainter.

Whether it's Norton's for simple orientation, finder charts for specific variable stars, or the Millennium Star Atlas for breadth of coverage, sometimes paper maps are so much more practical and convenient. They tend to be better annotated, for a start.
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