Author Topic: Episode #692  (Read 1631 times)

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Offline Steven Novella

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Episode #692
« on: October 13, 2018, 03:07:32 AM »
What’s the Word: Epistocracy; News Items: Ultrafaint Dwarf Galaxies, Monkeys and Wolves, WHO and TCM, Iron Age Sword, HPV Vaccine Update; Most Desirable Artifact; Science or Fiction
Steven Novella
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Offline elert

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Re: Episode #692
« Reply #1 on: October 13, 2018, 01:30:12 PM »
Some clarification is needed on magnetism. The magnetic properties of the elements have their origin in the intrinsic spin of subatomic particles — electrons in most everyday examples such a refrigerator magnets. The spin of the electron makes it a tiny magnet. This is a permanent and unchanging property of the electron.

Ferromagnetic elements have unpaired electrons in their outermost shells with an unusual behavior. When these electrons are near one another (when the atoms they belong to are adjacent in a solid lattice) they conspire to align in the same direction. Large groups of them will align in what are called domains. When all the domains in a chunk of iron share alignments, you have a strong permanent magnet. When many of them share alignments, you have a weak permanent magnet. When the alignments of all the domains are randomly directed, you have something that is not a magnet even though it is made of a magnetic material. Iron, nickel, cobalt, gadolinium, are dysprosium are the ferromagnetic elements. Some compounds containing these elements are ferromagnetic, like magnetite (Fe3O4). Some are not, like pyrite (FeS2). Surprisingly, some compounds made of non-ferromagnetic elements are ferromagnetic, like manganese bismuthide (MnBi) also known as bismanol.

A "not a magnet" can become a temporary magnet if it is placed in an external magnetic field (bringing an typical paperclip near a fridge magnet, for example). This changes the alignments of the domains into something that is closer to the direction of the external field. With more of the domains in closer alignment, the "not a magnet" is induced to become a magnet. When the external field is removed, the domains may or may not return to their original alignments. If they do, the object returns to its "not a magnet" state. (This can happen quickly or slowly depending on the element, compound, or alloy. Paperclips are made of steel. Fridge magnets are made of barium ferrite.) If the domains don't return to their original alignments, the magnet is now a permanent magnet and it will remain that way until another external field comes along to compel it to act differently. Iron fences have been known to become permanent magnets just because of how they were originally aligned in the Earth's magnetic field.

The magnetic properties of materials that are not ferromagnetic can be divided into two types of behavior — paramagnetism and diamagnetism. Paramagnetic materials exhibit a weak electron spin alignment when placed in an external magnetic field. Most elements are paramagnetic. The paramagnetism of liquid oxygen is a fun demo to try if you ever have access to liquid nitrogen and a strong magnet. You use the LN2 to condense drops of oxygen out of the air and have them fall near the poles of the magnet. The drops will deflect or, if you're lucky, stick to a pole and boil on it.

The opposite of paramagnetism is diamagnetism. Diamagnetic materials tend to align opposite an external magnetic field. Water is diamagnetic, but I can't think of any application of this knowledge. Superconductors are superdiamagnetic. They cannot hold an external magnetic field. Bringing a magnet near a superconductor induces eddy currents in the superconductor that behave like a mirror image of the magnet. A magnet next to a mirror image magnet results in repulsion. This is the basis of the liquid nitrogen cooled, magnetic levitation videos on YouTube — including .

Offline CarbShark

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Re: Episode #692
« Reply #2 on: October 13, 2018, 02:15:29 PM »
That’s one cool YouTube you got there


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and Donald Trump is President of the United States.

I'm not a doctor, I'm just a guy who has done a ton of research into diet and nutrition.

Offline PSXer

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Re: Episode #692
« Reply #3 on: October 13, 2018, 05:04:54 PM »
Is soldering really a subtype of welding? I've always heard (and a 10 second google search seems to confirm) that welding specifically refers to melting the pieces of metal to be joined, while soldering and brazing involve melting an intermediary metal between the pieces to be joined. Therefore, it's impossible that anything was welded with solder 3,000 years ago.

Semantics win again!

Offline Hampster

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Re: Episode #692
« Reply #4 on: October 13, 2018, 05:53:22 PM »
I missed the science of fiction because of the word welding. If Steve has use brazzing, I might have been so quick to judge.
WARNING- Opinions subject to change as new evidence emerges.

Offline lonely moa

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Re: Episode #692
« Reply #5 on: October 13, 2018, 06:00:12 PM »
Gardasil 9 requires being given twice.  Better than the alternative.

A couple of my good friend (both GPs) got their boys immunised promptly after I was diagnosed with OPC. 

The good thing about HPV caused OPC is that the treatment is pretty successful, if rather brutal, unlike OPC from tobacco use.  Seems to affect men in the 45-65 age range, although I met a woman my age who was treated for in the last year.

I was involved (just consent, really) in a study for HPV related OPC in NZ.  Turns out that one could almost rule out NOT being caused by HPV for non smoking men in my age group.

I am forever grateful to Mr Allison, the women on the linear accelerator and all the nurses on the ward (and of course my beautiful and long-suffering wife) for the cure. 
"Pull the goalie", Malcolm Gladwell.

Offline mddawson

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Re: Episode #692
« Reply #6 on: October 13, 2018, 09:36:36 PM »
Hey guys, try saying the following sentences:

"I sold a circuit board"

"I soldered a circuit board"

 ;)
"I only take scientific comments when they are peer-reviewed rather than being published in a small local newspaper or scratched on a toilet wall somewhere."
Professor Peter Brown (2005).

Offline brilligtove

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Re: Episode #692
« Reply #7 on: October 13, 2018, 11:01:57 PM »
"I sold her a circuit board"
vs
"I soldered a circuit board"
is a lot closer in a base middle Canadian accent, at least. Solder is pronounced 'sawder' so it's a stretch.

At that pendantree aside - I delight in the way you think.
evidence trumps experience | performance over perfection | responsibility – authority = scapegoat | emotions motivate; data doesn't

Offline mmortal03

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Re: Episode #692
« Reply #8 on: October 14, 2018, 02:21:48 AM »
The link for the article about "Monkeys and Wolves" on the show notes is wrong.

Offline Tassie Dave

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Re: Episode #692
« Reply #9 on: October 14, 2018, 03:45:01 AM »
"I sold her a circuit board"
vs
"I soldered a circuit board"
is a lot closer in a base middle Canadian accent, at least. Solder is pronounced 'sawder' so it's a stretch.

At that pendantree aside - I delight in the way you think.

Another word the North Americans pronounce differently.  ;) We pronounce it to rhyme with "older".

Offline 2397

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Re: Episode #692
« Reply #10 on: October 14, 2018, 05:07:14 AM »
I sold her a circuit board, but I didn't solder.

Offline elert

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Re: Episode #692
« Reply #11 on: October 14, 2018, 09:55:41 AM »
That’s one cool YouTube you got there


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Offline daniel1948

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Re: Episode #692
« Reply #12 on: October 14, 2018, 11:36:02 AM »
I believe it was Steve who said he'd like to own the first living thing, or maybe he said a fossil of it. The problem is that when you get very close to the line between living and not living, we don't have really good definitions. It seems likely to me that there was not an easily definable demarcation between the first living thing and its immediate predecessor.

Cara definitely won, though.

Personally, I don't have a great urge to own things of symbolic historic value. I would not even want to own the library of Alexandria, other than to donate it to people who could read the books in it. Those early fossils, I have no interest in owning them, though I really want the book about them that the person who discovers and studies them will write. I think meteorites are cool, but I have no interest in owning one, even though they are available and cheap.

I got SoF right this week. That happens maybe once every couple of months. I am way below chance. I generally do well on tests, but I'm lousy at SoF.
Daniel
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Offline lonely moa

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Re: Episode #692
« Reply #13 on: October 14, 2018, 01:58:56 PM »
Soldering sheet metal works because it has reasonable shear strength. 

Welding is a lot more fun, I'm glad it is an occasional necessity (or diversion) for me. 

"Pull the goalie", Malcolm Gladwell.

Offline Tassie Dave

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Re: Episode #692
« Reply #14 on: October 14, 2018, 02:59:33 PM »
I believe it was Steve who said he'd like to own the first living thing, or maybe he said a fossil of it. The problem is that when you get very close to the line between living and not living, we don't have really good definitions. It seems likely to me that there was not an easily definable demarcation between the first living thing and its immediate predecessor.

Cara definitely won, though.

She definitely won, though I do think they overstated the value of the Library of Alexandria and where human progress would be if it had survived. "Appeal to Antiquity Fallacy"  ;)

The Library might have been the greatest library of the time and hold hundreds of thousands of works, but there were libraries elsewhere and copies of most of the works.


 

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