Wikipedia:Reference desk/Archives/Science/2018 February 1

= February 1 =

"Weak Filling Condition" - What does it mean?
I'm trying to understand the following phrase and I can't. This phrase describes a product (pulse-oximeter) on Ebay and it states: "Measurement Performance in Weak Filling Condition: SpO2 and pulse rate can be shown correctly when pulse-filling ratio is 0.4%. SpO2 error is ±4%, pulse rate error is ±2 bpm or ±2%, whichever is greater." What does it mean "weak filling condition"? What does it mean "pulse filling ratio". I understand basic science but I felt to understand these things after trying many times. (I thought maybe it should be "weak feeling condition" where the pulse oximeter can't feel the pulse. But I'm not sure) — Preceding unsigned comment added by 185.191.178.183 (talk) 17:16, 1 February 2018 (UTC)


 * No idea if this helps: See our article on symplectic filling, which states: A weak symplectic filling of a contact manifold (X,ξ) is a symplectic manifold (W,ω) with ∂\partial W = X such that ω|ξ>0.  --Cookatoo.ergo.ZooM (talk) 17:37, 1 February 2018 (UTC)
 * Yeah, that's obvious [tongue-in-cheek] . Evidently, its a real thing, not a poor translation, or mistake.  E.g.: My vague understanding is that it is a form of interpolation (?). 107.15.152.93 (talk) 18:02, 1 February 2018 (UTC)
 * According to pulse oximeter, the actual measurement is of the amount of HbO2 and Hb change--the difference between minimum and maximum as the blood pulses--not the absolute amount in the light path. If there is a weak pulse, poor circulation, etc, the amount of change is smaller so the relative error in its measurement is greater. DMacks (talk) 18:34, 1 February 2018 (UTC)
 * I believe it relates to "filling in the (data) blanks"; relating to error minimization; i.e.: interpolation.2606:A000:4C0C:E200:211C:FF2A:3329:F571 (talk) 21:37, 2 February 2018 (UTC)

Breaking an opponents neck
It has been seen many times in movies, on TV and in other media where two people are fighting and one "breaks" the other's neck by twisting hard and resulting in immediate death. Is this accurate or even possible? Could even a trained (soldier, warrior, martial artist or whomever)kill an opponent in this manner? I have no doubt about serious injury (up to an including paralysis), but immediate death? If it is possible, what are the mechanics of it? 76.71.157.121 (talk) 22:11, 1 February 2018 (UTC)
 * A buddy of mine (who was giddy as a child about the detonation cord he got for Christmas, if that tells you anything) had a copy some hand-to-hand combat handbook for the US Marines. Can't guarantee that that move was or was not in there, but I'd be willing to bet $40 that it was followed with a stomp on the opponent's head to make sure they stayed down (as that's now almost every maneuver ended, even ones you'd figure would've killed the target five times over).  I don't know whether that indicates that it's actually really hard to kill someone by breaking their neck, because, again, this was a USMC handbook.  Ian.thomson (talk) 22:27, 1 February 2018 (UTC)


 * No neck grabs were part of the Marine Corps handbook as of 1990 (that is the date of mine). There are a few trip and take-down maneuvers. There is an arm-lock followed by a take-down. There is the standard "2 down low" followed by a take-down. All of the take-downs end with a head stomp. That is really only effective with the arm lock because it separates the shoulder. If done properly, the person will have a dislocated elbow and shoulder, making him unlikely to continue trying to fight. Of note, the purpose of hand-to-hand combat in the Marines is to get the opponent on the ground and incapacitated as quickly as possible. It isn't anything like boxing or MMA. You aren't scoring points or trying to pull cool moves. You just want to cause severe pain, very quickly, and move on to the next opponent. 209.149.113.5 (talk) 15:08, 2 February 2018 (UTC)


 * It involves very much the same mechanics as How to Dispatch a Chicken. It is a bit difficult to practice on humans in order to get the technic right. Not going to describe how the military are taught, because some twit reading this, may try it out in jest – and whoops – finds it works. It snaps the spinal cord, resulting in immediate paralysis and any attempts to resuscitate prove futile. Aspro (talk) 22:36, 1 February 2018 (UTC)


 * Cerebral hemorrhage is also likely with enough trauma to the upper spine with an elevated risk of instant coma or death. As a taekwondo practitioner, I've unfortunately witnessed an accidental death immediately after a kick behind the neck, death was almost instantaneous with visible bleeding from the eyes.  There's also a popular video of a similar incident during a live wrestling show.  This was not exactly spine twisting trauma, however.  — Paleo  Neonate  – 00:10, 2 February 2018 (UTC)
 * This is basically the same thing as the effect of "long drop" (warning, some unpleasant pictures in article) hanging: massive trauma to the brain stem. Such an injury usually causes rapid loss of consciousness. "Instant death" in complex animals only really happens with total disintegration, like having a nuclear weapon detonate directly on top of you. Otherwise, it takes at least a measurable amount of time for cardiopulmonary arrest to occur. (And the less complex the animal, the harder it is to get it to stay dead. Cut a flatworm in half, and now you just have two flatworms.) It should go without saying that most works of fiction are going to involve some artistic license. See for instance the Instant Death Bullet that live-action entertainment is fond of. --47.157.122.192 (talk) 04:10, 2 February 2018 (UTC)


 * It's dangerous to mess with the neck, even when you're not trying to kill or injure someone, .  In an American case, an unqualified trainer manipulated a man's neck in the bedroom vigorously and walked out of the house after the session.   The terrified man shouted down to his wife "I can't move!" and died shortly thereafter. 86.176.18.217 (talk) 13:28, 2 February 2018 (UTC)


 * Thank you for that comment user:86.176.18.217. Although it can't be performed as as depicted in the movies (where the actors don't want to kill each other for real). Knowing how to use mechanical advantage takes little strength to sever the spinal cord. Not much use in hand-to-hand combat. There, a striated blade plunged into the belly, turned and withdrawn causes so much pain that one's opponent is incapacitated and is so much quicker. A blade also avoid the emotional effect of touching ones opponent. Aspro (talk) 15:44, 2 February 2018 (UTC)

Thanks everyone. I have been a martial artist for over 30 years (karate, tae kwon do, aikido) and various instructors have "demonstrated" techniques that cause "instant death." I have never used any of these "techniques," of course but suspect that the effectiveness of them are more in the realm of myth or urban legend. . . and more likely to cause serious harm than actual death. Movies and television always tends to err on the side of the dramatic and artistic license than reality. 76.71.157.121 (talk) 23:24, 2 February 2018 (UTC)
 * I agree that there's a lot of mythology and pseudoscience in relation to martial arts. — Paleo  Neonate  – 19:20, 3 February 2018 (UTC)
 * One thing about TV and movies is time constraints. They can't spend a long time trying to show reality. They have to do the entire show to fit a one or two hour time slot. Hence other fanciful stuff, like getting DNA test results in like five minutes. ←Baseball Bugs What's up, Doc? carrots→ 22:21, 3 February 2018 (UTC)