PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please sub

[H2Oxide]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Wrong. I can think of countless examples where this doesn't hold up. Here are a couple.

"That man killed my wife and left her corpse in his trunk!"
"Objection, your honor; the investigators found nothing in his trunk."
"Absence of evidence is not evidence of absence!"

"That man shot me!"
"But the medical examiners found no bullet wound or other evidence of trauma"
"Absence of evidence is not evidence of absence!"

Absence of evidence IS evidence of absence if/when we expect to find evidence.

Alright Copi, calm down. It's just a common expression that has for some reason become associated with Carl Sagan. In this specific example it holds well, for if we hadn't investigated alternative medicine scientifically already, then the possibility of validity would still exist (to a degree).

 

[Encap]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Wrong. I can think of countless examples where this doesn't hold up. Here are a couple.

"That man killed my wife and left her corpse in his trunk!"
"Objection, your honor; the investigators found nothing in his trunk."
"Absence of evidence is not evidence of absence!"

"That man shot me!"
"But the medical examiners found no bullet wound or other evidence of trauma"
"Absence of evidence is not evidence of absence!"

Absence of evidence IS evidence of absence if/when we expect to find evidence.

yes exactly,---per the traditional aphorism, "absence of evidence is not evidence of absence", positive evidence of this kind is distinct from a lack of evidence or ignorance of that which should have been found already, had it existed.
The absence of evidence is evidence of absence only in case in which, were the postulated entity to exist, we should expect to have more evidence of its existence than we do.

Sagan's point was:
"Appeal to ignorance—the claim that whatever has not been proved false must be true, and vice versa (e.g., There is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist—and there is intelligent life elsewhere in the Universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we're still central to the Universe.). This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence."
From: Sagan, Carl (1997). The Demon-Haunted World: Science as a Candle in the Dark (1st ed.). New York: Ballantine. p. 213. ISBN 0-345-40946-9. OCLC 32855551.

The argument from ignorance for "absence of evidence" isn't necessarily fallacious, for example, that a potentially life saving new drug poses no long term health risk unless proved otherwise.
On the other hand, were such an argument to rely imprudently on the lack of research to promote its conclusion, it would be considered an informal fallacy whereas the former can be a persuasive way to shift the burden of proof in an argument or debate.
Carl Sagan often criticized such "impatience with ambiguity" with English asr=tronomer and cosmologist Martin Rees' maxim, "Absence of evidence is not evidence of absence" as found on page 3 of NASA's "Project Cyclops, A Design Study of a System for Detecting Extraterrestrial Intelligent Life." https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730010095.pdf

However---"In some circumstances it can be safely assumed that if a certain event had occurred, evidence of it could be discovered by qualified investigators. In such circumstances it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its non-occurrence."
~  Copi, Introduction to Logic (1953), p. 95

In the the field of medine/medical the distinction can become a life and death matter, not just pretty words.
"The non-equivalence of statistical significance and clinical importance has long been recognised, but this error of interpretation remains common. Although a significant result in a large study may sometimes not be clinically important, a far greater problem arises from misinterpretation of non-significant findings. By convention a P value greater than 5% (P>0.05) is called “not significant.” Randomised controlled clinical trials that do not show a significant difference between the treatments being compared are often called “negative.” This term wrongly implies that the study has shown that there is no difference, whereas usually all that has been shown is an absence of evidence of a difference. These are quite different statements."
From: Statistics notes: Absence of evidence is not evidence of absence. Martin 1995
See: Statistics notes: Absence of evidence is not evidence of absence | The BMJ

Bottom line--- No matter what our scientific theories, no matter what our human religions, reality remains a mystery. It's as simple as that.

An actual Saganism:
“Somewhere, something incredible is waiting to be known.” ~ Carl Sagan

Alright Copi, calm down. It's just a common expression that has for some reason become associated with Carl Sagan. In this specific example it holds well, for if we hadn't investigated alternative medicine scientifically already, then the possibility of validity would still exist (to a degree).

Yes however whatever any particular alternative medicine or medical practice as investigated reveals or not, it is still a pretty wide open field --the search for alternatives and many forms have merit and positive results as well.
What western medical science "knows" is very little compared to what it does not know and has a very limited ability to intervene effectively in human health and wellness.

Acupuncture. a very ancient form of healing which pre-dates recorded history, was long considered pseudoscience in the West yet it has a history of practice and results in China that goes back at least to 8000 years ago and probably long before that.
‘Acupuncture’ is clearly is not pseudoscience; however, the way in which it is used or portrayed by some may on occasion meet that definition. Acupuncture is a technique that predates the development of the scientific method. The contemporary use of acupuncture within modern healthcare is another matter entirely, and the fact that it can be associated with pre-scientific medicine does not make it a pseudoscience.
The primitive society of China is divided into two time periods- The Old Stone Age(10,000 years ago and beyond) and the New Stone Age (10,000-4000 years ago).During the Old Stone Age knives were made of stone and were used for certain medical procedures. During the New Stone Age, stones were refined into fine needles and served as instruments of healing. They were named bian stone - which means use of a sharp edged stone to treat disease. Many bian stone needles used in accupuncture practice were excavated from ruins in China dating back to the New Stone Age.

PS pseudoscience is just a new fangled modern derogatory term people use/employ for argument sake, when they have no answers for the most part, as if it's use as a prognostication of some sort, makes a difference.
"the oldest known use of the word “pseudoscience” dates from 1796 when the historian James Pettit Andrew referred to alchemy as a “fantastical pseudo-science” (Oxford English Dictionary).
Since the derogatory connotation is an essential characteristic of the word “pseudoscience”, an attempt to extricate a value-free definition of the term would not be meaningful. An essentially value-laden term has to be defined in value-laden terms.
This problem is not specific to pseudoscience but follows directly from a parallel but somewhat less conspicuous problem with the concept of science. The common usage of the term “science” can be described as partly descriptive, partly normative. When an activity is recognized as science this usually involves an acknowledgement that it has a positive role in our strivings for knowledge. On the other hand, the concept of science has been formed through a historical process, and many contingencies influence what we call and do not call science."
See: https://plato.stanford.edu/entries/pseudo-science/

 

[H2Oxide]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

And just like that, the eBay thread has turned into a discussion on the nature of reality.

 

[Alaskan]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

I like the glass, but the claims of what it can do based on what? Thought it was funny, and you are right, I was looking for a yellow wavelength coherent laser, all I can find is that 10 thousand dollar unit the seller can't test, or wont have tested. Not that I'd pay that anyway, so moot.

I like Diachi's find though: Melles Griot 5 Watts 532nm Class 4 Laser model: 85-GHS-305 - Lots of nice parts for a project in there, or if you can come up with a wiring diagram something to try to make work. (Note Diachi reserached this further, is really 2.5 watts). Diachi, since you have the cables etc., why don't you jump on this?

Good price for a compact 20 watt LPM http://m.ebay.com/itm/Thorlabs-D3MM...erMate-Plug-for-your-Multimeter-/252891069431

 

[Encap]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

I like the glass, but the claims of what it can do based on what? Thought it was funny, and you are right, I was looking for a yellow wavelength coherent laser, all I can find is that 10 thousand dollar unit the seller can't test, or wont have tested. Not that I'd pay that anyway, so moot.
Good price for a compact 20 watt LPM Thorlabs D3MM Thermal Laser Power Meter with MeterMate Plug for your Multimeter | eBay

Yes I agree. the "glass" is pretty deluxe. Perhaps will order one as a novelty/curiosity type thing to use as a paperweight.. People will undoubtedly ask what it is because of it's unusual appearance.

How about something to compliment the Quantum BioPhysics® AlphaSpin?New Yellow Next Coherent Energy Field Funnel | eBay.
A "travel model" 5.5W 589nm source based on a passively mode-locked Nd:YVO4 laser and a multi-stage Lithium Triborate optical
parametric amplifier seeded by a tuneable semiconductor laser, perhaps?

"In this paper we describe proof-of-concept experiments leading to the generation of several watts of quasi-continuous 589nm emission from an optical parametric amplifier (OPA) pumped by a passively mode-locked Nd:YVO4
MOPA (Master Oscillator Power
Amplifier) system. A significant advantage of our approach is that it comprises a linear optical chain that could be assembled from commercially available hardware and does not require fast switching electronics or active cavity stabilization."

This scheme can be assembled from commercially available non-developmental hardware and is readily scalable to high average powers. See here: "Generation of tuneable 589nm radiation as a Na guide star source using an optical parametric amplifier" Here:: https://openresearch-repository.anu.edu.au/bitstream/10440/960/1/Duering_Generation2009.pdf

PS Also interesting see: http://adsabs.harvard.edu/abs/2015SPIE.9650E..08L "To the best of our knowledge, this represents the highest average-power for all-solid-state sodium beacon laser ever reported."

Imagine 81W of 589.159nm pure joy to play with.

 

[diachi]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Diachi, since you have the cables etc., why don't you jump on this?

Good price for a compact 20 watt LPM Thorlabs D3MM Thermal Laser Power Meter with MeterMate Plug for your Multimeter | eBay

I don't have the money for it, otherwise I would!

That's a good deal for that LPM, nice find!

Here's a little fiber pumped Q-switched Nd:YLF head from Spectra-Physics. I was going to grab it, but again, no money.

SPECTRA PHYSICS 7960-L4-I LASER HEAD | eBay

Seller has another model too (last I looked), though it's much the same. Best I can tell it should do about 1W at 1047nm Q-switched, though I've found references to them doing 2W.

You'll need a fiber coupled pump and ideally a Q-switch driver. Can't remember pump power off the top of my head, pump should be 808nm, with maybe some temperature tuning to get it right IIRC. Q-switch drive power is mentioned in the manual somewhere, it's only a couple watts. Frequency isn't mentioned as far as I could see, just a frequency range for a watt meter to measure drive power.

Manual: http://www.bunkerofdoom.com/laser/spectraphysics/R Series User Manual.pdf

Some more information on a similar unit:
Untitled Normal Page

 

[Alaskan]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

I want that LPM but I have four laser power meters, I can't justify another one. I have one of those Spectra Physics heads already for 1060 nm output, was thinking of driving it with a wavelength locked 808 nm laser diode I have, it will put out up for 4 watts though, twice its designed input.

I've written the seller about the "5 watt" laser head and told him it was really 2.5 watts, but so far he has not changed his listing, if anyone else here would please contact him and let him know too, maybe you will convince him to change the listing and save some poor guy buying it thinking it is five watts: Melles Griot 5 Watts 532nm Class 4 Laser model: 85-GHS-305 - or perhaps he will ignore it, I don't know.

Diachi, is that DPSS the same one you have in your signature showing the inside?

 

[diachi]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

.

Diachi, is that DPSS the same one you have in your signature showing the inside?

The Melles 2.5W? Yes, although mine is the 2W, insides are the same with some variations between years.

Didn't know you had one of those SP heads already!

 

[Alaskan]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Got it last year

 

[paul1598419]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Got it last year

Cool, Alaskan. Any plans for it?

 

[Alaskan]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Toy, I got it cheap, don't know what yet.

 

[diachi]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Toy, I got it cheap, don't know what yet.

Nice little heads! I'm interested in the 1047nm (more than the 1064) for doubling to 523.5nm. Those are Q-switched so you should be able to do that fairly easily with extra-cavity SHG. Plus I had bought an Nd:YLF head years ago that went missing during shipping, wanted to bring that project back.

 

[Encap]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Toy, I got it cheap, don't know what yet.

Was surprised to see new 589nm, 50mW, 100mW, 200mW and 500mW Vaisho lab lasers on ebay at very discounted prices or best offer--prices about 60% to 70% off of what CNI gets for same output and quality 589nm

See: 589nm laser | eBay

 

[paul1598419]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Nice find, Encap. I put a bid on a 473nm DPSS laser, not working, for parts only. I'd appreciate it if no one here bids against me.

 

[Alaskan]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

I've seen that seller list a couple of those every week or two, first his shipping was 45 dollars to Alaska, now over 80 dollars. The shipping price keeps me away.

 

[paul1598419]

Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please

Didn't know. I thought you might be interested.