Wikipedia:Reference desk/Archives/Science/2018 January 11

= January 11 =

Does normal salt intake cause cardiovascular disease and high blood pressure by depressing the renin–angiotensin system?
We can read here that taking in very low amounts of salt (less than 0.1 grams a day) leads to elevated levels of aldosterone and renin and on the long term you then don't see the usual rise in blood pressure with age. So, could it be that by adding salt to our diets at the RDA levels (note that a few grams of salt is already 50 times the natural amount), we achieve a normal blood pressure but in the wrong way, and that this causes the blood pressure regulation to not work as well causing damage to the arteries on the long term that in turn causes arterial calcification which leads to hardened arteries and blood pressure rise? Count Iblis (talk) 00:36, 11 January 2018 (UTC)


 * Dude, you began with your own reference. Don't ask us to give medical speculation on it; read the guidelines. μηδείς (talk) 02:16, 11 January 2018 (UTC)


 * What guidelines???? Count Iblis (talk) 14:13, 11 January 2018 (UTC)
 * The ones that say we're not supposed to speculate here. We're supposed to provide reading material (references) in the form of reliable sources.  Since you, yourself, just provided your own reference, and then ask us to speculate on it, Medeis is just noting that that sort of thing is not what we do here.  It is explicitly written in the guidance at the top of this very page.  -- Jayron 32 15:28, 11 January 2018 (UTC)
 * Yes, Medeis is right, of course. It's entirely logical that a 42 year old suggestion in the literature would be taken to be the last word in the scientific community. Without even searching the literature, we can be 100% sure that there is nothing more to be found in the literature, therefore anything anyone could possibly have to say must be pure speculation, so let's hat this question! Count Iblis (talk) 15:45, 11 January 2018 (UTC)
 * I never said any of that. I'm not sure why you would want to hat the question now. Here is an overview of more recent studies about heart health and salt intake.  Here are the most recent recommendations of the American Heart Association.  The problem is that the phrasing of your question "could it be that..." is leading and an invitation to speculation.  If you had phrased it "what is the current research on..." then you would have gotten a different response.  -- Jayron 32 15:52, 11 January 2018 (UTC)

Titanic
If they knew then what we know now about hypothermia, would it have been possible to save at least some of the people who died on the Titanic (I don't mean those who went down with the ship, but specifically the ones who jumped into the water)? Because the Carpathia arrived on the scene only a couple of hours after the great ship went down, and it's not exactly unknown for a hypothermic victim to be revived after such a time, right? 2601:646:8E01:7E0B:1DAB:D57B:F9C8:4AE0 (talk) 05:16, 11 January 2018 (UTC)


 * (Fixed your link.)
 * In the article you linked, the section Hypothermia suggests an answer of "maybe yes". Of course the number of victims who could be intensively treated would have been limited by the number on board the Carpathia who were qualified to do so.  The best chance of revival would have been with children.  Beyond these points we get into speculation, which we should not do here. --70.29.13.251 (talk) 06:56, 11 January 2018 (UTC)
 * According to our article Lifeboats of the RMS Titanic the Saveguard planning was insufficient and what was available was badly organized on top. Of course they already knew then that humans dont survive in ice cold water. The Titanic was not the first ship in history that sank in bad weather. Shurely with more Precaution almost everyone could have been saved. You can even argue if the captain had known a little more about Icebergs - but the big surprise is that everyone already knew back then everything important to know about icebergs. --Kharon (talk) 07:22, 11 January 2018 (UTC)
 * What I meant, though, was that we now know (but they didn't know then) that people sometimes DO survive in ice-cold water despite being mostly dead to all appearances (as the article on hypothermia points out) -- so my question was, with this knowledge alone, could they have saved more people even with all the other factors remaining the same? 2601:646:8E01:7E0B:1DAB:D57B:F9C8:4AE0 (talk) 09:45, 11 January 2018 (UTC)
 * Yes. ←Baseball Bugs What's up, Doc? carrots→ 10:23, 11 January 2018 (UTC)
 * How many extra lives could have been saved depends on what alternative history one cares to speculate. With the knowledge at the time of Titanic's sinking April 1912 it would seem obvious that earlier rescue with treatments such as a hot bath, massaging arms and legs, using a heating pad, and possibly giving alcohol could have saved more from death by Hypothermia. Today it is known that such treatments risk causing blood to be directed away from vital organs to the skin, see Hypothermia#Management. Modern recovery treatments for severe hypothermia such as extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass, including cardiopulmonary resuscitation (CPR) for those without a pulse are most effective but they would have required a well equipped Hospital ship to be present at the scene. SdrawkcaB99 (talk) 11:50, 11 January 2018 (UTC)


 *  Review of probable survival times for immersion in the North Sea from the UK Health and Safety Executive, on p. 22 points to the example of the Ocean Ranger, a mobile offshore drilling unit that sank in Canadian waters on 15 February 1982. The standby vessel arrived within 20 minutes of the sinking, but capsized a lifeboat while trying to rescue survivors. Those that fell into the sea could not hold on to the lifeboat or rescue lines and died. "It is apparent that in cold water sea conditions, the survivors who were not equipped with immersion suits succumbed within minutes to cold shock and hypothermia". I'll leave you to read through the rest of the data and evidence, but it's clear that two hours in the winter sea in your dinner suit is not survivable. Alansplodge (talk) 12:03, 11 January 2018 (UTC)


 * Circum-Rescue Collapse also makes interesting reading: "After the first Battle of the Falkland Islands [in 1914], it was reported that most of the 200 survivors from the German battlecruiser Gneisenau died on board one of the rescue ships". This underlines SdrawkcaB99's point above about the limited understanding of the condition at that time. The standard treatments used then are recognised as positively harmful now. Alansplodge (talk) 12:21, 11 January 2018 (UTC)

Cool flame
How did Sir Humphry Davy discover cool flame? Our article mentions that he produced the flame and accidentally noticed its coolness, but it doesn't mention what he did to produce it in the first place. All I'm finding with Google is numerous references to the fact of discovery, with (again) no mention of the process. Here's a good candidate for article expansion, if we can get a source. Nyttend (talk) 12:51, 11 January 2018 (UTC)
 * Reference no 5 in the cool flame article provides the answer - "H. Davy (1817) "Some new experiments and observations on the combustion of gaseous mixtures, with an account of a method of preserving a continued light in mixtures of inflammable gases and air without flame," Philosophical Transactions of the Royal Society of London, 107 : 77-86. On p. 79, Davy inserted a hot platinum wire into a mixture of air and diethyl ether vapor: "When the experiment in the slow combustion of ether is made in the dark, a pale phosphorescent light is perceived above the wire, which is most distinct when the wire ceases to be ignited. This appearance is connected with the formation of a peculiar acrid volatile substance possessed of acid properties." (though I do wonder if he really wrote vapor rather than vapour). Wymspen (talk) 13:09, 11 January 2018 (UTC)
 * Ah, sorry, I failed to check the references; I figured that whoever added the sources would have added the "how" if the sources supported it. Nyttend (talk) 13:14, 11 January 2018 (UTC)