Wikipedia:Reference desk/Archives/Science/2014 December 9

= December 9 =

What a shock! You almost gave me a heart attack!
What's the mechanism for heart attacks from severe emotional distress or extreme surprise? I've read Myocardial infarction, but I didn't see anything that answered this question; it mentions causes, but some (e.g. obesity and smoking) are long-term things, and the only immediate cause that I saw was related to the plaque that tends to build up in people suffering from the long-term causes. Nyttend (talk) 03:25, 9 December 2014 (UTC)
 * This article explains how one can be literally "scared to death" and discusses the mechanisms for how it happens. -- Jayron  32  03:57, 9 December 2014 (UTC)


 * This same answer seems to come from a press release, here from http://health.clevelandclinic.org/2014/01/surprising-heart-attack-triggers/ : It turns out that extreme emotions, both good and bad, can have an impact on the electrical impulses of the heart. Studies show that the stress spanning extreme happiness to acute grief has the ability to spur a heart attack. This is due to the body’s involuntary and sudden increase in heart rate and blood pressure brought on by a surprising event. The article seems to contradict itself by mentioning a sudden increase in blood pressure, and an increased risk of death up to a month after losing a loved one. μηδείς (talk) 04:02, 9 December 2014 (UTC)
 * Thank you; I didn't know what to look for, since "scared to death" just returns tons of colloquial uses and publications with this in the title. Are there many other species that can be scared to death through the same way?  As a former rabbit owner, I remember reading that I should ensure that my pet be free from sudden shocks and surprises, since apparently the species is prone to being scared to death, but I don't know if they die the "same way" or differently, let alone about other species.  Nyttend (talk) 04:12, 9 December 2014 (UTC)
 * More: The mechanisms seem to be caused by a sudden onrush of adrenaline to the heart. There's also other mechanisms, such as this article from Johns Hopkins University that discusses so-called "broken-heart syndrome".  Wikipedia has an article on the phenomenon at Takotsubo cardiomyopathy, which discusses specifically how emotional stress can cause acute heart problems.  -- Jayron  32  04:17, 9 December 2014 (UTC)

Diabetes and hypoglycemia
My understanding is that diabetes should tend to cause hyperglycemia and never hypoglycemia. Thus, is the only reason that diabetics are at particular risk (beyond that of the general population) of hypoglycemia due to the medication taken to counter the diabetes? --78.148.108.98 (talk) 04:30, 9 December 2014 (UTC)
 * According to Diabetes mellitus and List of causes of hypoglycemia you seem to be basically correct. Diabetes is caused by the body's inability to produce insulin; since insulin is involved in glucose metabolism, it seems like the only reasonable cause of hypoglycemia in diabetics is medication problems; basically it's the sign of an over-correction, not caused by the diabetes itself.  -- Jayron  32  04:44, 9 December 2014 (UTC)
 * As a minor clarification, only type 1 diabetes and possibly some cases of Gestational diabetes and may be a few other more minor types are definitely related to be bodies inability to produce insulin. Type 2 diabetes is characterised by insulin resistance and the body may produce too much, too little or normal levels if insulin production. You could still say their body isn't producing enough insulin in the sense that it isn't producing enough to be able to regulate their blood glucose level with insulin insulin resistance (our article says something similar in the history section). Somewhat relevant to the original question, the first line of management for type 2 diabetes is usually life style changes i.e. diet & exercise. (Diet & exercise may help people with type 1 diabetes, but there's current no good treatment that doesn't involve additional insulin.) I would guess since people are trying to control their blood sugar level, there's also a risk they may go to far in this regard and so be at increase risk from hypoglycemia. On the other hand, they may also be at lower risk since they are monitoring their glucose levels and more acutely area of the risk. If that isn't enough, then anti-diabetic medication and possibly including insulin will be used, and these will as you say carry a risk of hypoglycemia if a mistake is made or something unexpected occurs. Nil Einne (talk) 11:53, 9 December 2014 (UTC)
 * There is a type of Type 1 diabetes known as brittle diabetes, in which the islets of Langherhans normally do not produce insulin, but occasionally recover their function and start producing insulin. Since the patient is injecting insulin to compensate for the diabetes, the occasional recovery of functionality results in hypoglycemia, sometimes severe hypoglycemia, which can be fatal.  That is, in the absence of injectable insulin, the patient would usually be hyperglycemic, and sometimes normal.  With insulin, the patient will usually be more or less normal, and sometimes hypoglycemic.  The answer to the original question is yes, the risk is only due to the medication to counter the diabetes, except that the medication nonetheless increases the life expectancy.  Prior to the discovery of insulin, the Type 1 diabetic would die within a few years of the onset of the diabetes, probably in their teens or twenties.  With insulin, the life expectancy of the brittle diabetic is higher, but they will die randomly, possibly in their thirties or forties.  I don't have a reference at this time.  Robert McClenon (talk) 16:39, 9 December 2014 (UTC)

Facial surgery
Tevildo (talk) 00:57, 10 December 2014 (UTC)

Deaf and blind people interacting with traffic
I've heard that deaf people have complained about the safety of shared space streets, and blind people have complained about quiet electric vehicles. What are some technological solutions to make deaf and blind people safer as pedestrians? What policy actions could the government take to address these issues?--79.97.222.210 (talk) 15:16, 9 December 2014 (UTC)


 * This sounds like homework - is this homework? Anyway, we have an article on Electric_vehicle_warning_sounds, and here's a news article on the topic of public safety, blind people, and quiet vehicles . If this is homework, you should check these and other sources. It also might be interesting to discuss how these issues play out with bicycles a bit. SemanticMantis (talk) 15:37, 9 December 2014 (UTC)
 * Shared spaces are a ludicrous idea and hazardous to all users, regardless of modes of transport or ability. — Preceding unsigned comment added by 131.251.254.154 (talk) 15:53, 9 December 2014 (UTC)
 * This shouldn't be dismissed as homework; it ought to be a political issue of substantial interest, since if electric vehicles become a dominant force it determines what the cities of the future will sound like. From the political perspective I find it remarkable that the federal government, after decades of claiming to be helpless to act on issues like brake retarders and other vehicle noise that is documented to cause substantial, measurable health problems for the population as a whole, would suddenly get involved only to make vehicles noisier.  I would like to see a direct comparison between the number of lives of pedestrians expected to be saved by mandated noise versus the number lost due to cardiovascular and other noise associated health issues.  This should also be considered in the context of vehicular automation and systems that might simply stop the slow-moving car safely rather than plowing through the pedestrian.  I also would really like to know why something like autonomous car technology isn't already available to the blind in a hat camera or the like so that they can get warnings and navigation advice wherever they go.  The use of a few talking street intersection signs in a city is at once drastically annoying to those unfortunate enough to be located nearby, yet all but useless for allowing the blind real independence. Wnt (talk) 16:09, 9 December 2014 (UTC)
 * I didn't dismiss it, but the wording makes it sound like an assignment. I'm happy to provide some refs but I'm not in the habit of doing people's homework for them. I agree that the issue is interesting and important, that's why I replied at all. Additional useful links might be Americans_with_Disabilities_Act_of_1990 and there's even some decent refs and info at crosswalk. SemanticMantis (talk) 17:25, 9 December 2014 (UTC)

Ethics of cloning humans without brains
Would it be possible in the near future to create and grow a cloned human with most of its brain missing (i.e. not alive) to use in medical research? What do ethicists think about this? I'm assuming here that if there's no brain there's no person, am I right?--Goose Geyser (talk) 16:29, 9 December 2014 (UTC)
 * Are you asking about cloning a human with most of their brain missing, or about cloning a human with all of their brain missing, or about cloning human cells? My guess is that you are really asking about cloning human cells for use in research, not about cloning a partial human.  I am not an ethicist, but I think that most ethicists would agree that cloning a human with most of their brain missing is very unethical.  Can you please restate your question? — Preceding unsigned comment added by Robert McClenon (talk • contribs)
 * Wikipedia has an article titled Ethics of cloning which may help the OP. Ethics are not universal scientific laws, they are negotiated by people to allow for best practices to develop and to minimize potential problems.  Such ethical principles will only have been elucidated insofar as the people involved have negotiated them and put them down on paper somewhere.  -- Jayron  32  17:05, 9 December 2014 (UTC)


 * To your first question, no - we can grow some human tissues in the lab, and we can clone some entire animals - but we cannot in the near future grow a human that is "not alive" with "most of its brain missing" - the brain is a necessary part of ontogeny. Also the "no brain there's no person" thing is highly contentious, see some info at brain death. Some people out there believe that a zygote should have rights of a legal person - some history and legal perspective on that at abortion law. SemanticMantis (talk) 17:21, 9 December 2014 (UTC)


 * My guess is the OP could be suggesting something like a machine connected to a brain-less body to maintain basic living functions, similar to an iron lung, and maybe even aid growing cells a little in organizing. --84.180.255.151 (talk) 17:35, 9 December 2014 (UTC)
 * That's fine and all but we can't grow a brain-less body of a human in the near future. Human development_(biology) and fetus talk a bit about how the brain factors in to growing a human body. SemanticMantis (talk) 18:27, 9 December 2014 (UTC)
 * Yes, the ip is right, that is what I was asking. I am still interested in reading about the ethics of this idea.--Goose Geyser (talk) 18:56, 9 December 2014 (UTC)
 * I still don't understand the question. I see a distinction between cloning human tissues, cloning human organs, and cloning a brainless, or partially brainless, human body.  Robert McClenon (talk) 18:58, 9 December 2014 (UTC)
 * Could you please explain the ethical difference between cloning one human tissue and cloning all of the human tissues except the ones that give one a consciousness? If you're not creating a conscious human, I don't see who is harmed. I don't understand the distinction, one is just a subset of the other--Goose Geyser (talk) 19:17, 9 December 2014 (UTC)
 * It is as Dragons flight explained. The development of the brain is part of the process of the development of an organism, in this case a human.  In the case of mammals, the only way that I know of to clone an organism is to clone the DNA into an ovum and have it develop in a uterus, in which case a brain would develop.  Removing the brain in utero would be killing the fetus, rather the developing a fetus that never had a brain.  Cloning tissues is one process.  Cloning an organism is a different process.  Your opinion may vary, possibly with your religion, but I find the idea of removing the brain from a developing fetus to be repellent, even worse than abortion (which at least can be argued to be for convenience of the mother).  Robert McClenon (talk) 20:50, 9 December 2014 (UTC)


 * There's no process that I can imagine that would allow a whole human to develop without a brain that doesn't necessarily involve starting with a whole human and then cutting out / killing most of the brain. I think many people would regard it as grotesque to take a whole human with a brain and then intentionally destroy the brain.  It is the metaphorical, or perhaps literal, equivalent of chopping the head off of a fetus.  Abortion is certainly a relevant parallel here as we are talking about an intentional intervening act that would prevent the development of a human life that could have been normal.  I can't imagine many people would be happy with a process that involved destroying fetus brains.  If there is some alternative that gets you to nearly whole human without doing something like that, then I'm not sure what it is.  Dragons flight (talk) 19:37, 9 December 2014 (UTC)
 * Exactly. Robert McClenon (talk) 20:50, 9 December 2014 (UTC)
 * Anencephaly already exists - it's rather amazing that a fetus can develop with such a normal appearance despite the condition. But I don't know if there are any countries that wouldn't "frown upon" using the anencephalic children for destructive research, while large sums are often spent for their health care. Wnt (talk) 01:07, 10 December 2014 (UTC)
 * As that article says, the condition is not really the complete lack of a brain, but the failure of most of the brain to develop. Robert McClenon (talk) 15:27, 10 December 2014 (UTC)
 * Just wanted to point out that some parts of the brain produce hormones which are an important part of the endocrine system. I don't think this is a bridge we'll have the ability to cross any time soon. 78.148.108.98 (talk) 16:34, 12 December 2014 (UTC)

Defences against EMP
Just now coming from watching the 2005 version of War of the Worlds where aliens are attacking earth by EMPs (just paused it to ask my question here, so please no spoilers!), obviously with the main intent to shut down most vehicles and communications so people won't be able to flee and keep attacked areas from communicating with those that are still intact and unaware of the coming peril. Now, I know from the top of my head that EMPs were one of the threats both sides were preparing against during the Cold War because they would come with large nuclear explosions. AFAIK, that's why they also created ARPANET as the main forerunner to today's internet, so political figureheads in some fall-out shelters deep below the ground could still comunicate with any surviving armies on the ground even if most other electronic devices would be destroyed by giant EMPs.

So now I'm wondering, is there really a way for special devices for communication and long-range vehicles to still work even if an enemy force is purposefully using EMPs to destroy our main means of mobility and communication? In the film, the aliens have strong lightning keep hitting the very same spot on the ground a number of times until they're obviously certain the job is done for the area. Let's assume they have utopian technology to create basically infinitely strong EMPs, that probably gives us an upper limit for how strong their EMPs can be without blowing up Manhattan physically, rather than just creating a hole in the street, right? Now, whether that gives us an upper limit or not, would there be an absolute fool-proof way to prepare against these EMPs beforehand so you'd still have any way of far-range communication and mobility left? From what little I could gather from Wikipedia so far is that Cold War technology obviously worked by putting devices into Faraday cages, but once a certain amount of energy is reached, an attacker could basically melt even said cage from the outside, right? And finally, I could assume that with how they were drilling a hole in the street, it would have probably been effective for them to directly hit the city's power supply system the cables of which should be below the street, so they'd also directly attack all local power plants within the system, right? --84.180.255.151 (talk) 17:16, 9 December 2014 (UTC)


 * What? Is that some classified military knowledge, or something? :P --84.180.255.151 (talk) 19:26, 9 December 2014 (UTC)
 * A Faraday cage should shield of any EMP attack. --Kharon (talk) 20:24, 9 December 2014 (UTC)


 * Computers in combat aircraft continued to use Magnetic-core memory long after it was considered obsolete everywhere else because it's able to retain it's content during an EMP. SteveBaker (talk) 21:16, 9 December 2014 (UTC)


 * The premise here is extreme. I remember reading of a case in which someone "struck by lightning" had a gold chain melted (I doubt they were really hit, more likely those reporting didn't understand induction).  But it's one thing to melt a very thin chain next to the source and something else again to melt a nuclear submarine in the middle of the ocean (which is often a good place to shop for a perfect gift for such visiting aliens).  It's hard to picture directing all that energy to burn out circuitry, or even aiming this "EMP", without simply exploding every car and steel frame building an equal distance from the alien ship.  The effect on membrane potential might not be compatible with life - the existence of positive and negative charges in the cell implies that it ought to pick up energy from such a force.  But ultimately... an alien weapon based on physics we don't understand might do anything. Wnt (talk) 00:58, 10 December 2014 (UTC)


 * I don't see this as worth answering because anything is possible on the silver screen. The aliens, whilst looking for transmitter targets, might equally tune into an omnibus edition broadcast of the Osmonds Greatest Hits and get their brains fried.  Film scriptwriters note: A lack of any alien defense against that - I would find more credible!--Aspro (talk) 01:49, 10 December 2014 (UTC)


 * The only utopian element in my question was that of infitely strong EMPs. I gather that laws of physics can be more or less easily applied if that's the only supernatural element of the core question, hence I also exchanged the word "aliens" with "an attacker" or "an enemy force" from time to time in my question. SteveBaker and Wnt did give me some appropriate answers to ponder. So basically, combat aircrafts would crash, but the computers in them could stil be useable, as long as they were safe from any ground impact damages, and nuclear submarines that at the time of the attack were located in the ocean would also still work? And because of the basic lack of directability of EMPs, it would be impossible to off entire local power systems without blowing up cars, steel frames, and all living organisms first? PS: Funny Osmonds reference! :P --84.180.255.151 (talk) 08:48, 10 December 2014 (UTC)
 * Well, you can put out local power systems with a regular human EMP; they are super vulnerable because they involve loops of power lines that are many miles wide. But if you can surround something in a thick vault of conductive metal my skepticism increases in proportion to its conductivity.  Now I can't say for sure there's no trick around this - for example, an extremely low frequency signal can penetrate the reasonably conductive waters of the ocean to get a message to a submarine.  But an ELF signal isn't exactly what I think of when I think of EMP, and while conceptually aimable the wavelengths are still in the kilometers to thousands of kilometers, and there are suspicions of danger to human health at levels of emission vastly, vastly lower than what would be needed to actually destroy equipment with it. Wnt (talk) 14:00, 10 December 2014 (UTC)
 * Well, at least you're giving me confidence that no EMP attack could work like in the movie, no matter the nature of the aggressor, because obviously, no EMP (be it high or low frequency) could work as effectively as that without endangering all living organisms physically. Anyway, when you mentioned membrane potential, it kinda reminded me of the 1985 UK pilot movie to the later Max Headroom US series where people exploded because of electro-chemical overload in all body cells from being bombarded with subliminal messages. --84.180.255.151 (talk) 18:15, 10 December 2014 (UTC)
 * Oh, and there's more interesting physical thought experiments to ponder from the movie: At several times, we see the military try and attack the three-legged alien vehicles with what looks like conventional artillery, which is obviously useless against the shielding the aliens use. I wonder how much shielding could still be physically possible if they'd gone for the last-ditch effort and dropped the big N on them. I remember once reading a sci-fi/fantasy story with a similar theme where Satan had displaced the infernal city of Dis into the desert of Nevada where the army also tried attacking it with conventional means to no avail. Their far-range sensors are telling them that the city obviously has a surface temperature of several thousand degrees C, so one of the generals goes, "Looks like those Medieval bastards can take the temperature of molten lead, but let's see how well they respond to a temperature several ten-thousand times that of the surface of the sun!", and they drop a nuclear warhead on Dis. What they then see through their telescopes and sensors is how the city and the demons inside it shortly evaporate because their atoms are melting, before reforming (the narrator explains that their physical appearance is made up of atoms controlled by spirits) with some obvious problems at first while their atom structure is still volatile, but eventually successfully. So what's physics telling us about material resilience, or generally the behavior of matter, at 100 million degrees C as occuring inside a nuclear blast? --84.180.255.151 (talk) 18:57, 10 December 2014 (UTC)
 * Hm. Trying to find answers to this last question (how matter behaves at the temperatures found inside a nuclear fireball), I came upon Hagedorn temperature, which is the temperature where all hadron particles (including atoms) vaporize (there's also a separate, even higher Hagedorn temperature for strings). But the article is not telling me exactly how hot the Hagedorn temperature for vaporizing hadrons is, it only contains its equivalent in mass-energy. --84.180.255.151 (talk) 20:26, 10 December 2014 (UTC)

How many lecture hours does a bachelor of science have?
How many lecture hours does a bachelor of science have? — Preceding unsigned comment added by EPsande (talk • contribs) 17:42, 9 December 2014 (UTC)
 * I doubt that you are going to get a useful answer unless you are a lot more specific. A BSc in what subject? At which university? Different subjects will require a different balance between theory and practice, and individual teaching institutions will often have very different ideas as to what method is best for learning. And of course the better-funded institutions may have opportunities that those working to limited budgets don't, being for example able to replace lectures with tutorials involving smaller groups. AndyTheGrump (talk) 18:00, 9 December 2014 (UTC)

Isn't the definition of credit defined somewhere? I am thinking about the UK, right now. But there must be a minimum of hours that allows you to call a course bachelor. — Preceding unsigned comment added by EPsande (talk • contribs) 18:08, 9 December 2014 (UTC)


 * Where I went to school in the US, you needed a minimum of 120 semester hours to complete any degree. A semester was typically 15 weeks, so that would be about 1800 hours of in-class instruction.  The typical course was 3 credit hours (e.g. 3 hours of lecture per week for 15 weeks), and people aiming for a 4 year graduation would need to average about 15 credits per semester (typically 5 courses).  Many people had more than 120 credit hours at graduation due to initially exploring different possible degree paths or taking many electives that were not relevant to their ultimate degree.  About 70 of the required credits were specific to my degree program, an additional 40 credit hours were general education requirements (e.g. writing, history) that were required of everyone.  The last 10 credit hours were available for any non-major electives, though many people had more electives than that by the time they graduated.  I recall being told to expect 3 hours of out-of-class assignments and studying for every hour spent in lecture.  In practice, I'm not sure how accurate that was, and the assignment load varied greatly with the individual courses.  Dragons flight (talk) 18:05, 9 December 2014 (UTC)


 * My experience was very similar to User:Dragons flight's. Graduation required 120 credits, a three credit course had three hours of lecture (with an assumed 3 hrs of study) and fulfilments of the major as well as six distribuion classes which would include things like history, literature, and a language.  I double majored, (almost tripled), so I ended up taking about 140 credits, but that's only 17.5 credits per semester.  We had twelve actual weeks of lecture, plus holiday breaks and a two-week finals period, so, again, about "15" weeks.  Actual major requirements were minimal, but the trick was all the other courses one had to take or test out of as prerequisites.  Philosophy required upperlevel classes in Decartes, Hume, Kant, Aristotle, Plato and an option (in my case, Spinoza) as well as Epistemology, Metaphysic and Ethics.  Biology was similar, you had to take the calculus, physics, and organic chemistry prerequisites, but the Major only included Physiology, Zoology, Genetics, Ecology, and a specialization, which for me was Botany, Plant Ecology, and Limnology, all with 3hr labs that counted as 1 credit hour. Had I not almost triple majored, the 120 credits of 3 credit hrs of 12 weeks would have been easy.  That's 1,440 class hours but probably twice as much in study hours since labs and writing were intense. 1,800 seem almost on the spot, given labs were 3hr long but only counted a 1 credit hour. μηδείς (talk) 21:21, 9 December 2014 (UTC)


 * Institutions such as the Open university provide courses courses that use distance learning and so the actual lecture time is limited and most of them are provided on DvDs etc. Richerman    (talk) 18:35, 9 December 2014 (UTC)


 * In the UK, it's not a matter of number of hours as such, as the level at which those hours are taught at that makes a course a degree level (Bachelor) course. The article Qualifications and Credit Framework will give you an idea of levels, and in particular the diagram on the page. I'm used to the preceding framework, having retired from HE lecturing in 2010, which recommended a certain number of credits at levels 4 and 5 for any honours degree, but the principle is still the same. The first year will be at level 4, the second year at level 5, the third year at level 6. As for number of hours you will be expected to attend lectures, this will vary considerably between subjects and universities. --TammyMoet (talk) 20:22, 9 December 2014 (UTC)

Let's see, for engineering in the UK in 1980 I had 20-25 hours of lectures a week for 22 weeks, in the first year. The number of lectures slackened off in the other two years (I didn't bother with many lectures in the 3rd year, preferred to work in the library), but yes, rather more than a thousand hours, and about the same again in labs and tutoring and so on. Plus papers and lab writeups. We did a lot more work than the scientists, not as much as the lawyers or medics or vets. Greglocock (talk) 22:00, 9 December 2014 (UTC)

If you cannot breath, can you say "I cannot breath?"
Can you? — Preceding unsigned comment added by EPsande (talk • contribs) 19:30, 9 December 2014 (UTC)
 * You can still speak and be heard as long as you can hold your breath unless you are in a vacuum where sound can't be transmitted. --2.245.95.53 (talk) 19:47, 9 December 2014 (UTC)


 * Audible speaking requires that some air move past the vocal cords; however, the amount of air needed is small. It is certainly possible to be able to speak (weakly) without being able to move enough air to maintain safe levels of oxygen saturation in the blood.  This can happen with a partial airway obstruction, or with lung capacity impairment such as those caused by pulmonary edema or physical compression of the chest.  Dragons flight (talk) 19:59, 9 December 2014 (UTC)


 * You don't need to use your vocal cords to speak, producing a continuous voiceless velar fricative suffices as a pseudo-voice. Plasmic Physics (talk) 20:28, 9 December 2014 (UTC)


 * Heh. By which PP means a choking sound, presumably?  It still requires some air flow. μηδείς (talk) 21:27, 9 December 2014 (UTC)


 * Not really a choking sound. A voiceless velar fricative involves the tongue and soft palate, and does not require choking. That being said, yes, it does require exhaling air flow. Plasmic Physics (talk) 04:25, 10 December 2014 (UTC)


 * (ec) Being unable to say it would be a red action level for an asthma attack. Rmhermen (talk) 20:02, 9 December 2014 (UTC)


 * For information, the verb is "breathe", with two "e"s. "Breath", with one "e", is what goes in and out of your body when you breathe. Bazza (talk) 20:39, 9 December 2014 (UTC)


 * It's also possible that (in the case to which you obviously refer), the choke-hold was released sufficiently to allow some words to escape and then re-applied as the victim struggled.  Under that kind of pressure, someone is unlikely to give exact details..."I can't breathe adequately" or "I can breathe right this very instant - but 10 seconds ago I was desperate for air".   It would be dangerous to assume that because someone was able to emit those words that he was in fact getting sufficient oxygen.   Also, his body was doubtless in "Fight-or-flight response" mode with every bodily function amped up to the max...it takes a lot of oxygen to maintain that level of involuntary activity. SteveBaker (talk) 21:09, 9 December 2014 (UTC)


 * I have allergy-related asthma. I am able to say "I can't breathe", then I get my inhaler, and do not attempt to discuss the legality of selling loose cigarettes.  If I were being choked and tackled that might be a serious problem. μηδείς (talk) 21:27, 9 December 2014 (UTC)


 * It appears that the real problem there was not so much the choke hold, but the fact that he was very rotund and the cops had him on his belly, apparently oblivious to the risk that put him in as it would tend to constrict his organs. So he might be able to breathe enough to say "I can't breathe", but not enough to get enough oxygen to avoid catastrophe. ←Baseball Bugs What's up, Doc? carrots→ 21:47, 9 December 2014 (UTC)

Folks, please remember that the purpose of the science reference desk is to provide scientific reference. Discussions about current events that are not direct requests for scientific reference belong in a different forum. Nimur (talk) 22:53, 9 December 2014 (UTC)


 * It wasn't until SteveBaker's comment above appeared that I realised what the question was about. The event you refer to has only been briefly mentioned in the news here (UK). I thought that the question was from someone with English as a second language. Bazza (talk) 23:27, 9 December 2014 (UTC)
 * It has been well-covered on BBC. Here's one example. ←Baseball Bugs What's up, Doc? carrots→ 10:08, 10 December 2014 (UTC)
 * For the benefit of people who read this page in the archives, or for readers who are not following present American news closely, the issue in question is covered by our article Death of Eric Garner, in which the use of the phrase "I can't breathe" has become a contentious and inflammatory issue regarding the use of police force in the United States.
 * We can assume good faith and we can answer the original question posed here using scientific references that are suitable for an encyclopedia. If anybody seeks encyclopedic reference regarding the event, we can politely point them to the main article and remind them that current events do not fall under the purview of the science reference desk.  This topic is covered in the article.  Questions of encyclopedic merit about other aspects of this topic may belong on other areas of the reference desk.  Inflammatory discussion and speculation do not belong anywhere on Wikipedia, because Wikipedia is an encyclopedia; there are other forums in which such discussions may be conducted, preferably by polite participants conducting informed discourse.  Nimur (talk) 23:57, 9 December 2014 (UTC)


 * I agree that it's not our business to come to conclusions in a case like this - but on the other hand, answering the question literally, while pretending that we don't understand the context in which it's being asked is just a waste of everyone's time. So, be dispassionate and neutral about the events and conclusions of culpability - for sure - but consider that the real situation was that this guy was (allegedly) in a choke-hold at the time he (allegedly) said those words - sometime before (allegedly) dying from suffocation.  I believe that the answer I gave above fulfills that criterion.  I don't believe that it's sensible to say that because the guy said those words, he wasn't being choked.  I don't know whether he was actually being choked or not...only that one shouldn't rule out the possibility on the basis of that utterance. SteveBaker (talk) 02:45, 10 December 2014 (UTC)


 * Does that mean I can't ask questions about Rosetta and Philae since their use and operation constitutes a current event? --78.148.108.98 (talk) 03:49, 10 December 2014 (UTC)
 * Assuming you're referring to the comet lander, I don't think any reliable source has connected that to the Garner case. ←Baseball Bugs What's up, Doc? carrots→ 10:08, 10 December 2014 (UTC)


 * There are two kinds of chokehold: blood chokes and air chokes. If your throat is squeezed closed, you're not talking. If your carotid arteries are squeezed closed, it can feel like you can't breathe, because your brain doesn't get the oxygen, but the wind still works. "I can't respirate" would be the more proper, less catchy, thing to say. During a struggle, a rear blood choke with the crook of an arm can easily slide to an air choke with the forearm and back again, even unintentionally. That's just one thing to consider in this case, and maybe not as important as the position and health of the opponent. InedibleHulk (talk) 04:08, 10 December 2014 (UTC)


 * This guy's trachea was apparently fine, ruling out an air choke. InedibleHulk (talk) 04:13, 10 December 2014 (UTC)


 * In Eric Garner's case, the coroner ruled his death a homocide due to "compression of neck (chokehold), compression of chest and prone positioning during physical restraint" (my emphasis). Lie on the ground and ask a heavy friend to sit on your chest, so that you can exhale but not inhale.  Then you'll understand exactly how someone can say "I can't breathe" while being unable to breathe.  Hopefully the friend agrees to get up before you die--otherwise, your own coroner's report might look similar to Garner's.  --Bowlhover (talk) 05:08, 10 December 2014 (UTC)
 * Through Google, I see some sources putting "chokehold" in parentheses, and others just quoting "compression of neck". The ones which use "(chokehold)", sadly, seem to all be from five days ago, by which time Wikipedia had already synthesized it as such. If the actual report only says compression of neck, a reverse chinlock can't be ruled out. If anyone survived Bowlhover's advice, try letting your friend add the chinlock. If you're brave, go full-on camel clutch. It's not quite choking or strangling, but the squeeze sure feels deadly. InedibleHulk (talk) 08:45, 10 December 2014 (UTC)
 * I would be quite surprised if the OP were not talking about the Garner case, as it has been extremely visible in the news recently. And as noted, initial reports kept talking about the chokehold, but as the coroner's report indicates, it was the position they made this guy lay in which prompted the "can't breathe". ←Baseball Bugs What's up, Doc? carrots→ 10:04, 10 December 2014 (UTC)
 * And/or the asthma, obesity and hypertension. All contributed, all can cause dyspnea. InedibleHulk (talk) 10:41, 10 December 2014 (UTC)


 * I had been wondering about the blood chokes vs. air chokes above. I doubt this is the explanation, but could a blood choke create a false sensation of being unable to breathe?  Could a blood choke kill someone but not create evidence at autopsy that was not reported in this case?  It would useful if there were data we could add to the article that clearly raises or completely rules out that possibility. Wnt (talk) 18:29, 10 December 2014 (UTC)
 * Yeah, a blood choke can kill you, but not without leaving lactic acid evidence in the brain. And yeah, it can feel somewhat like suffocating. Press your thumbs against your carotids for a few seconds to get the gist of it. InedibleHulk (talk) 01:44, 11 December 2014 (UTC)
 * Erm, that's one piece of medical advice I'm definitely not going to take. I have enough reasons why I ought to fear strokes and arterial wall dissections without pressing ... my luck. Wnt (talk) 05:11, 11 December 2014 (UTC)
 * Fair enough. I don't need that on my conscience, either. If you want to play it extra safe, read the section on defending chokes in that "can kill you" link. You never know when it might be handy. I'll bet Jack Dealy didn't expect he'd need a shady flying head scissors to put some fear in the heart of a genuine bloody, axe-wielding maniac in his underwear. InedibleHulk (talk) 07:38, 11 December 2014 (UTC)
 * His brain isn't getting oxygen either way. I didn't follow the details but it seems as if the carotid hold did not result in unconsciousness, considering his verbal responses, and his positioning is what caused the asphyxiation.  If he did lose consciousness from the carotid hold and was left in a poor position, he'd just die from continued lack of oxygen.  See Sleeper hold  --DHeyward (talk) 23:30, 10 December 2014 (UTC)
 * He wasn't asphyxiated (suffocated) at all. He had a heart attack in the ambulance. Because of the circumstances of the struggle, he felt like he couldn't breathe, but if he couldn't, he'd have died in a few minutes. The temporary compression and anxiety deprived him of enough oxygen to contribute, along with his poor health, to the heart attack. InedibleHulk (talk) 01:44, 11 December 2014 (UTC)
 * I'm not following it particularly closely. If he was in ambulance, he should have had 100% O2.  Without tracheal damage, I would think asthma would be the next cause.  I was under the impression he died at the scene but if he was in an ambulance, it was the exertion of the fight.  Cops die on duty from exertion related illness in significant numbers related to other line of duty deaths.  --DHeyward (talk) 09:50, 11 December 2014 (UTC)
 * If a person being choked says, "I can't breathe," he means "I am having difficulty breathing, to the point of panic, please stop choking me." He does not mean "I am technically incapable of moving air past my trachea into my lungs. Just thought you'd like to know." - Nunh-huh 03:19, 11 December 2014 (UTC)
 * "Stop choking me" or "get off of me". It's a very common utterance from the bottom guy on Cops, especially after a foot chase. The officer on the show often responds with the same sort of "Yes, you can" attitude Garner's cops did, and the generally solid advice to "stop resisting". When many people survive the same thing for long enough, the words lose their urgency. Same goes for those in the "safety" of "the chair". InedibleHulk (talk) 03:42, 11 December 2014 (UTC)
 * "Stop Resisting" is a trained verbal command. It's part of use-of-force training.  It's the justification for moving to the next progression.  Engaging in discussion/conversation with someone saying they can't breathe is also trained.  Generally police will call for medical personnel upon request especially a large department like NYPD and definitely if they don't converse/yell/fight after saying they can't breathe.  Positional asphyxiation is also taught and they should try to avoid positions known to cause heavier people difficulty (i.e. handcuff extensions and laying them in a manner where it's easier to breathe).  --DHeyward (talk) 09:50, 11 December 2014 (UTC)
 * I imagine it's not easy to resist the instinct to resist beating. —Tamfang (talk) 09:52, 11 December 2014 (UTC)


 * Does everyone else see literal question marks around the "never" in "should never be used as a means of punishment?" InedibleHulk (talk) 03:57, 11 December 2014 (UTC)