Wikipedia:Reference desk/Archives/Science/2017 September 17

= September 17 =

Vaccination boosters
Why are adults, other than those at high risk, not offered a booster for the chickenpox vaccination if the dose given at childhood doesn't last a lifetime? 90.198.254.50 (talk) 09:08, 17 September 2017 (UTC)
 * You didn't say where but I see from your ip it is the UK. My guess is because the NHS is being stretched far too far by austerity and have far more important things to spend their money on. But even if it was offered it probably wouldn't be worth it till people were 60 and their immmune systems started to get weaker and they got more liable to get shingles, there's enough chickenpox around still anyway to keep the immune system primed normally. If we were halfway towards eradicating chickenpox it probably would be worthwhile doing booster shots more generally until it was totally eliminated - but that isn't viewed as any sort of important target at the moment. There have been efforts to eliminate measles but those have been stymied by stupidity and ignorance in the developed world in refusing the MMR vacine. Dmcq (talk) 12:30, 17 September 2017 (UTC)
 * In the case of testing for bowel cancer every patient is written to every two years between the ages of 65 and 70 I believe, and the letters say that those over 70 are welcome to request a self - test pack.  So far as I know, testing and vaccination for common diseases is given on request - I wouldn't like the OP to think (s)he can't have a vaccination if (s)he wants one.   If you've had shingles once you can get it again, and vaccination does not provide complete protection. 82.14.24.95 (talk) 12:54, 17 September 2017 (UTC)
 * Varicella vaccine is given two times not just one. It is often given on the same schedule (1 year and 4-6 years) as the vaccinations against measles, mumps and rubella (MMR). There are even combined quadrovalent vaccines for these diseases. The third adult (or booster) dose is not given by the same reason as for MMR: it is generally considered pointless. The vast majority will remain immune for life after two doses. So, returns are diminishing quickly for any additional dose. Ruslik_ Zero 18:59, 17 September 2017 (UTC)


 * The Zoster vaccine article discusses the various US, UK, and European recommendations. It's basically a high-dose chickenpox vaccine for adults, either over 60 or at risk. -Arch dude (talk) 20:22, 17 September 2017 (UTC)
 * There is a confusion here with zoster vaccines. They serve a different purpose and are give to those who are already infected. The question was about a vaccine to prevent the primary infection. Ruslik_ Zero 20:28, 17 September 2017 (UTC)
 * Our varicella vaccine article seems to me to discuss the issue well. What do you think is not adequately answered by the article? --47.138.161.183 (talk) 05:41, 18 September 2017 (UTC)


 * Well I personally know of at least one person that contracted shingles just weeks after receiving a chicken-pox/zoster vaccine a few years back so (just a guess but) maybe that sort of occurrence has become common enough to motivate health officials to refrain from recommending the scheduling of that shot for all but the highest risk categories? My overall take on the whole thing basically this: a correctly prepared and properly stored vaccine administered at the right time to a person whose state of health is sufficiently "just so" will most likely experience positive-to-neutral results, otherwise there is always the inherent risk that comes with injecting foreign (and potentially dangerous) agents into one's system. And you can't necessarily rely on the conclusions reached in peer-reviewed studies because most are directly/indirectly funded by the health-care industry itself which is naturally in the business of selling stuff and minimizing legal liability. So look at the raw data and be very wary of interpretive statistics. For example, when the question comes up as to why adults are not typically offered a booster for the chickenpox vaccination, suppose you eventually come across papers such as this one (which unequivocally asserts that there is "no evidence of a statistically significant change in the rate of increase [of shingles onset] after introduction of the varicella vaccination program") take careful note of the the highly-presumptive interpretation and then draw your own conclusions accordingly using just a bit of logic and reasoning. 73.232.241.1 (talk) 12:57, 19 September 2017 (UTC)
 * Exactly what in all that conspiracy theory contradicts what I said above? I said there was enough chickenpox around to keep up the immune system primed normally. However older peoples immune system can be weaker and need a bigger jolt to keep in order. Dmcq (talk) 17:30, 19 September 2017 (UTC)

Is it true to say that "in every disease the entire body is involved"?
I'm reading now a medical book which stays "in every disease the entire body is involved". Now, I am not sure if every disease involves every system in the body. 93.126.88.30 (talk) 15:09, 17 September 2017 (UTC)


 * Yes, that does seem a bit silly. Acne doesn't normally effect your pancreas, for example.  Perhaps they could say "potentially could become involved", as an infection that starts from, say, acne, could eventually spread to, say, the pancreas.  StuRat (talk) 15:45, 17 September 2017 (UTC)


 * What do you mean by "medical" here? It's clearly starting from the point of holistic medicine, but the woo woo is strong is such fields and the risk is that it can easily diverge into nonsense such as homeopathy. Discussion and rational coverage of such fields is forbidden at WP, and any detailed coverage of them is just blanked with a redirect to a single simple bucket of ridicule, as if all are equally unworthy of consideration. Andy Dingley (talk) 15:55, 17 September 2017 (UTC)


 * If I get a severe cold or flu, it certainly "seems like" the entire body is involved, but to turn that experience into some kind of generalized truism seems highly suspect. ←Baseball Bugs What's up, Doc? carrots→ 16:08, 17 September 2017 (UTC)


 * The OP needs to cite title, author, edition and page if he wants any sort of real help. And presumably the author has defined his terms and that sentence does not sit alone, but is found within an argument.  I wouldn't come here with the sentence from one of my favorite books, "Now it's broken and needs to be fixed", and expect comment if I didn't give the context so that editors could make sense of its significance. μηδείς (talk) 17:46, 17 September 2017 (UTC)


 * Not everything requires context. "Elephants are a kind of fish" is just plain wrong, regardless of context.  On the other hand, "whales are a kind of fish", could be correct, in some contexts, like "According to the archaic classification system of X, whales are a type of fish". StuRat (talk) 19:24, 17 September 2017 (UTC)


 * But elephants are fish, at least cladistically... it's in the lead section of the article. Wnt (talk) 19:39, 17 September 2017 (UTC)


 * Yes, Wnt, I had to laugh when Stu laid that whopper. Stu also thinks a graphic from the US Forestry Service hosted at the Boston Globe showing the reforestation of the Eastern US since 1900 is right-wing hate speech.  Oh, well.  A little knowledge is a dangerous thing. μηδείς (talk) 20:39, 17 September 2017 (UTC)


 * No, your misrepresentation of what it said was right-wing misinformation, not hate speech. StuRat (talk) 20:49, 17 September 2017 (UTC)


 * Well, no, that's not what you said either, but I knew I could count on you to take the bait. Here's the link to your original suggestion that a Forestry Department report at the Boston Globe was misinformation from a right-wing website.  You have to understand, Stu, that some of us are actually credentialled in some of the fields we comment on, and know what sources to go to to prove our point, rather than just immediately answer every question posted on these desks based on some Faygo-intoxicated guess. μηδείς (talk) 01:41, 18 September 2017 (UTC)


 * That's exactly what I said and I stand by it. If you want to debate it, that was the place, not here.  That link DOES NOT SAY, AS YOU CLAIM "According to the trend from 1850 to 1920, according to this government map, the US would be entirely void of trees at this point."  That's you just making crap up. StuRat (talk) 01:56, 18 September 2017 (UTC)


 * I'm all for correcting people to be excessively pedantic, but not just to make a case against them (I'm not directing this at any particular party). We should return to the topic. Wnt (talk) 02:17, 18 September 2017 (UTC)


 * Agreed. Hatted. StuRat (talk) 02:26, 18 September 2017 (UTC)


 * I think the idea is pretty much correct -- at least, if we take "involved" to mean potentially affected during the future course of disease, rather than noticeably damaged. For example, acne might cause dermatillomania, depression, and apparently on some famous occasions can lead to septicemia and even death.  Obviously, an intact and well-functioning immune system should keep the acne contained, but then again a truly well-functioning immune system probably ought to have stopped the acne to begin with.
 * I would anticipate that the moral of the story might be the need for a complete medical history... no matter what. Wnt (talk) 18:11, 17 September 2017 (UTC)


 * The difference between "involved" and "could potentially become involved" seems rather critical in a medical context. If a doctor said "your pancreas is involved" instead of "could potentially become involved", that would be malpractice. StuRat (talk) 19:21, 17 September 2017 (UTC)


 * Every disease might be an overstatement, but the great majority of diseases activate either a stress response or the immune system, both of which cause changes pretty much throughout the body. Looie496 (talk) 19:06, 17 September 2017 (UTC)

"normally closed" relays
Please could you tell me what consumer electronics are likely to contain "normally closed" relays. I know microwaves contain "normally open" relays which switch to "normally closed" when power is applied. Thanks for your time. — Preceding unsigned comment added by 36.85.29.51 (talk) 18:17, 17 September 2017 (UTC)


 * Some type of overheat switch which opens when the device overheats, then you hit the reset button to close it again ? For example, a hair dryer might have this.  StuRat (talk) 19:11, 17 September 2017 (UTC)


 * I think my first electronic experimenter kit as a kid had at least one of each ... I would make those things buzz... the FCC probably had a van out looking for me. ;) Wnt (talk) 19:43, 17 September 2017 (UTC)


 * An un-interruptable power supply (UPS) might have a NC relay on its mains input. The mains will be connected to the UPS output unless the UPS actively decides otherwise and disconnects the mains by energizing the relay coil. (In fact, the relay will probably be SPDT with the mains on the NC input and the inverter on the NO input) -Arch dude (talk) 20:17, 17 September 2017 (UTC)


 * Sounds like you already got some good answers, but to be clear, most general purpose relays have both a normally open and normally closed pin making it a SPDT (single-pole double-throw) switch. As far as applications, they're all over the place. A magnetic door lock for example, and as mentioned anything that during a power loss, you want it to close a connection (probably to some other system), so you see them a lot in safety type applications where you need a "cut-off" of some sort. As just a fun fact, you can use a DPDT relay to make a forward / reverse controller for a motor. When the relay is activated, the motor goes forward, when de-activated, it reverses the polarity, see these in kid's electric cars a lot. Drewmutt ( ^ᴥ^ ) talk  02:13, 20 September 2017 (UTC)

Walking/running downhill energy consumption
Walking/running downhill: what consumes more energy for a human?--Hofhof (talk) 21:08, 17 September 2017 (UTC)


 * Considering the high amount of energy we burn just standing still, whatever gets you to the bottom fastest would "stop the clock" and thus reduce the total amount of energy burnt for the trip. That would be running.  However, if you phrase the Q differently, such as "What method will get you to the bottom of the hill and consume the least energy, over the course of an hour", then a slow walk would probably be better, since the clock no longer stops when you get to the bottom.  The temperature would figure into it, though.  If it's so cold that mere walking results in shivering, then running may conserve energy. StuRat (talk) 21:14, 17 September 2017 (UTC)


 * There are actual sources for this on line. These are rather basic: http://healthyliving.azcentral.com/burn-many-calories-running-downhill-18961.html https://www.verywell.com/how-many-more-calories-do-you-burn-walking-uphill-3975557. Both show that it is easier going downhill either way, and you save about 6% walking downhill.  The amount saved depends on the incline, and past a certain point the calories saved decreases as the slope gets steeper.  Neither of those sources gives any charts or formulae or much in the way of detail, but if the popular press is covering this, I expect their are more formal studies as their sources. μηδείς (talk) 01:33, 18 September 2017 (UTC)
 * The steepness is also relevant if you're having balance problems: if it's so steep that you risk falling down the hill, your effort to balance yourself and stay on your feet might take a bit of energy, and of course you're likely to be steadier (and thus require less balancing effort) if you're going more slowly. Of course, if you fall down on a steep slope, you may expend no energy (other than the basal metabolic rate) in descending the rest of the hill, but that might cause the expenditure of energy for other purposes.  Nyttend (talk) 01:55, 18 September 2017 (UTC)
 * According to the laws of physics downwards should be far easier and with lower energy consumption. However it seems to be the opposite, with walking, in reality. Not because of physics but because of lake of training, humans are not used to constantly decelerate bipedal motion, thus usually very ineffective in doing that and thus, physically paradox, need more energy walking downhill. --Kharon (talk) 05:15, 18 September 2017 (UTC)
 * I used to do a lot of hillwalking and the descent phase always gave me sore quadriceps femoris muscles. A lot of walkers get knee pain from descents, a condition called Iliotibial Band Syndrome. It's the stress of controlling the speed of your footfall, a problem that is going to be worse if you're running; more speed equals greater kinetic energy. I have seen people lose control when descending too fast, a jog turns into enormous strides, turns into head-over-heels tumbling. Quite comical unless you meet any large rocks on the way.  Alansplodge (talk) 10:14, 18 September 2017 (UTC)
 * When I climbed Mount Kinabalu on the standard guided tourist route from Timpohon Gate, I had a similar experience. Ascending was fairly tiring. Normally done over two days which is what I did, I think that's mostly because if you want to do it over 1 day you have to make good time and also may not reach the summit at the best of times (it can cloud over sunrise) and also for commercial reasons. Unless you're fairly fit and making good time, on the first phase you'll have porters speeding past you with large gas bottles etc on their backs, which at very least means you probably aren't going to moan when you see the food prices in Laban Rata (even despite recognising the porters aren't getting much from that). The second phase from Laban Rata is not as long although I think steeper on average (the vertical ascent is less than the first phase but the distance is even less) and with more tricky terrain and also generally done mostly when it's dark and given the altitude you may get mild altitude sickness. The descent follows on from the second phase of the climb (i.e. the total climb is over 2 days). From memory, the descent is not quite so tiring overall but boy can you feel it in the legs as most information guides note, probably for days afterwards. And this was as a ~19 year old albeit not that fit. IIRC my travel companion actually read stuff suggesting that some people found jogging or running down was actually kinder on the legs, but it's not something I researched myself. This source for example  suggest other things and on another issue it notes that doing it may seem to reduce pain on descent, but actually increase the required recovery time. Nil Einne (talk) 12:34, 18 September 2017 (UTC)


 * User:Kharon, the sources I cited said you always expend less energy walking or running down hill, but that at steeper slopes the energy saved is less because the stride becomes irregular. At some point you are simply climbing downhill, and using your legs to break a fall, but at that point it's not really walking or running anymore.
 * User:Alansplodge, one of the sources actually recommends running down hill as a good way to build quadriceps muscle, hence your soreness on doing this--its a different type of exercise. μηδείς (talk) 20:44, 18 September 2017 (UTC)
 * Note to self - always read the references that you link :-) Most older hillwalkers in the UK use trekking poles in an attempt to reduce the impact on their knees. Another point is that when planning a route using Naismith's rule, you add time for ascent (usually 1 minute for every 10 metres up) but don't add time for descent. Alansplodge (talk) 10:13, 19 September 2017 (UTC)
 * Perhaps we should start using Tobler's hiking function instead of Naismith, though the spike in its graph makes it look rather implausible to me. AndrewWTaylor (talk) 16:28, 19 September 2017 (UTC)
 * But if you would use an ebike that has an recuperation capable controller, you could even fill up your batteries on the way. So be smart, buy your very own ebike asap!:D --Kharon (talk) 21:49, 19 September 2017 (UTC)

Civil engineering asset management
Is asset management and ongoing maintenance in civil engineering generally more closely aligned to civil engineering design and consulting as opposed to construction? 90.198.254.50 (talk) 22:30, 17 September 2017 (UTC)
 * Civil engineering is a huge field of Work and civil engineers are typically "jack of all trades" since they have to recon with everything that may happen to their construction, design or planning. So ofcourse asset management and maintenance seems to have no direct connection to design, construction and its planning but since it usually is an essential part of all that is designed, constructed and planned, they have to learn how that is done too. --Kharon (talk) 05:33, 18 September 2017 (UTC)