Wikipedia:Reference desk/Archives/Science/2017 March 5

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March 5

Is there any evolutionistic explanation for the gender split?

Additionally, how come the split is into pairs rather than into triplets and likewise, evolutionistically speaking? HOTmag (talk) 00:59, 5 March 2017 (UTC)

See Evolution of sexual reproduction. In short, the division of sexes reduces the number of harmful traits in a gene pool while still increasing the amount of variety. I'm not immediately seeing anything concerning pairs (though I just woke up), but it's probably because machines with the fewest moving parts are the least likely to break. Mating requiring two individuals is risky enough, the more you add the more risk there is that a suitable partner will die. There are, however, a variety of Sex-determination systems, including XX/XY, XX/X0, ZZ/ZW, and ZZ/Z0; with some intersex possibilities depending on the species. Ian.thomson (talk) 01:19, 5 March 2017 (UTC)

I would not say it is the division of the sexes that does what you state, but sexual reproduction itself. There are organisms that can reproduce sexually despite having only one gender, such as earthworms, and organisms in which there are no obvious differences between the two genders, such as baker's yeast. See also Sexual dimorphism. Someguy1221 (talk) 01:29, 5 March 2017 (UTC)

Scientifically, you probably mean "sex", as most scientists consider "gender" to be something to do with social norms and perhaps grammar. Anyway, there are FAR more than two sexes! Well, assuming that by "gender" in this case something like mating type, which are the different types of critters within a species that can/or cannot sexually reproduce with each other. Humans only have two mating types, but it gets more complicated for other organisms. For interesting examples of this, see mating in fungi. A famous example is the Schizophyllum_commune, which, through combinatorics of Mating-type_region, has over 28,000 different sexes! Also check out Anisogamy for a basic way many organisms have split. SemanticMantis (talk) 15:35, 5 March 2017 (UTC)

Gender refers to the distinction between male and female. See Gender. Blooteuth (talk) 22:52, 5 March 2017 (UTC)

Sex is biological, gender is a social construct. Evolution of gender would be a very different thing, and that's not what OP is asking about. The Sex_and_gender_distinction is easy to understand, and easy to respect when speaking of science. Well, apparently not for you. Good luck with that, but fair warning, if you go around using "gender" to mean "sex", you'll sound ignorant, and it will make people question whether you really know what you're talking about. SemanticMantis (talk) 19:35, 6 March 2017 (UTC)

Speaking as a scientist...hahahaha no, scientists don't care. Maybe this is a thing in gender studies, but not in any scientific conversation I've ever been party to. Someguy1221 (talk) 04:20, 10 March 2017 (UTC)

• Seriously? DNA forms complimentary DOUBLE helixes. But yes, let's all get frantic over politically correct use of sex versus gender versus whatever the hell else, rather than answering the question. DNA splits in two. Two sexes. Not π sexes, not 15 genders. Two fucking sexes. Mitosis rules! Offer not valid off Terra. μηδείς (talk) 04:10, 10 March 2017 (UTC)

Puncturing an automobile tire

For reference later on — I have P175/70R14 tires (Walmart profile for one brand thereof), although I don't know the manufacturer's brand. I'm not immediately able to find references to the thickness of this model's rubber on the sidewalls.

While driving on a gravelled forest road today, I found myself with a slow tire leak, and the tire-repair store's employee found a small twig embedded in the interior sidewall (how bizarre!). As you can see, the whole thing was about 45mm in length with a diameter somewhat exceeding 5mm; when holding the original, I can't identify the type of wood (although I wonder if it's maple, judging by the bark), and I don't have any clue what kinds of trees were lining the area where I picked it up. The mass is apparently 1.1 grams — I constructed a crude balance out of a ruler and fulcrum, with this stick on one end and toothpicks as the weights on the other, and eleven toothpicks (average mass 100 grams, according to this webpage) balanced out the stick. Please note the shape of the end toward the left side of the picture, which is what penetrated the sidewall.

Is it possible to calculate the minimum force required to puncture a tire with these specifications, and if so, is it possible to calculate the minimum velocity of this 1.1g piece of wood at the moment of impact? Or would we have to consider fluid dynamics (for the air), precise details about the shape of the pointed end, and other factors that I'm not able to handle? Nyttend (talk) 04:34, 5 March 2017 (UTC)

I find it hard to visualise a 100g toothpick, unless King Kong uses them. DuncanHill (talk) 15:04, 5 March 2017 (UTC)

Oops, yes, 100mg. Nyttend (talk) 00:38, 6 March 2017 (UTC)

Bizarre indeed. You say it was embedded in the interior sidewall -- do you know whether the point of entry was through the sidewall, or through the tread? Modern radial tires are pretty tough in the tread but much less so in the sidewalls. Shock Brigade Harvester Boris (talk) 04:50, 5 March 2017 (UTC)

In case you wonder, this was definitely what happened: the guy jacked up the car, removed the lugnuts, and pulled off the wheel as I was standing next to him and watching the whole thing, so he and I discovered the wood plug together and watched the tire deflate rapidly when he pulled it. There were plenty of little sticks on the road; I suppose that I ran over one with another wheel, sending bits flying, and one of them got stuck. And by "interior" (I have no clue if this is "standard" terminology), it was the left side of the front-right tire, i.e. the side of the tire closer to the engine and farther from where the curb would be if gravel roads in the woods had curbs. To answer your question: if the "bottom" of the sidewall is where it meets the hubcap, and the "top" is where the tread begins, it was near the top — about at the level of the little lettering (including the word "explosion") at File:Fix-a-flat.jpg, i.e. between the tread and the word "DOUGLAS" in big text. Nyttend (talk) 04:58, 5 March 2017 (UTC)

It's not the force that matters, but rather the pressure, and for that you would indeed need to determine the contact area of the point and the tire. Did you by any chance lose traction and have the wheel spin while in that area ? I've found that this is a way for sidewall damage to occur, as the tire spins against a branch, in your case. Another possibility is if the tire was underinflated, causing the sidewall to touch the pavement. StuRat (talk) 05:08, 5 March 2017 (UTC)

Tire was previously at normal pressure (high 30s PSI), so the sidewall had no way to touch the pavement in that manner, while I witnessed no tire traction issues; there were mud ruts, but they'd all dried out, and the road was otherwise fine aside from plenty of small shallow holes (mostly occupied by puddles) and assorted washboarding zones. Nyttend (talk) 05:13, 5 March 2017 (UTC)

The ruts could do it, lowering the tire to where the sidewall was in contact with the edge of the rut, which presumably had the twig sticking out. StuRat (talk) 05:28, 5 March 2017 (UTC)

Yes, the ruts must have concentrated a significant proportion of the weight of the car onto this small twig. I've had this happen with sharp stones, but I think you were extremely unfortunate to have this happen with a small piece of wood. In almost all cases, the wood should snap before the tyre is penetrated, but the angles must have been just right for compression of the wood without any shear forces. My guess is that this low-probability event will never happen to you again. Dbfirs 08:38, 5 March 2017 (UTC)

Unless proven otherwise I'm going to guess the twig was at the tip of a much larger branch that anchored it in the ground. It might also have had a sharp tip that cracked off as it punctured the tire and was lost inside. Even if it doesn't look freshly broken now, it's possible that going around and around as part of an auto tire "weathered" the twig down to a bare essential that seems blunt ended? This isn't really science because (hopefully!) it will not be reproducible. Wnt (talk) 11:43, 5 March 2017 (UTC)

Good point about the broken tip; it means that we can't create an accurate answer to my original question. Note to the people immediately above: sorry to have accidentally led you down the wrong path, but I should have previously noted that I stayed away from the ruts, fearing that they might be wet (look for "shallow" at [1], the last time I drove on a road of this quality), and my estimation that they were dry is derived from the generally dusty state of the road. Nyttend (talk) 12:17, 5 March 2017 (UTC)

• You should consider the unfortunate but likely possibility of being just another victim of a crocked tire mechanic. It's common practice among some tire places to add the extra service of inserting a screw (usually a large tapcon) from the inside. They just love to see you come back for more tire :)) --TMCk (talk) 00:22, 7 March 2017 (UTC)

@TracyMcClark: That sounds like some kind of urban legend to me. It would only take one unrelated tire mishap to reveal the screw inside the tire waiting to screw out (? I don't even get the geometry ?) and then the owner would be solving a locked-room mystery with a tire that he knows who last had it depressurized, which doesn't require Sherlock Holmes! And all that for business that would probably go to the nearest shop at the time of the rupture, which means only a few percent return, offering a few percent profit... it just doesn't make sense. Unless you provide a reference I'm calling this one busted. Wnt (talk) 13:33, 8 March 2017 (UTC)

Thanks for pinging. The only thing busted is/was my tire after a blowout on the highway. Of course it could've just been a magical screw that found it's way inside and screwed itself in. I had not considered that possibility at the time.--TMCk (talk) 15:16, 8 March 2017 (UTC)

@TracyMcClark: Is it possible you ran over a piece of thin wood or panelling in the road? If it had been ripped from a wall with the sharp end of a screw poking out the back (which I've seen often) then if it landed with that end down the panelling would be held up by a screw balanced on its point. When your tire ran over the wood, the panelling would break loose from the screw and be pushed down, or just broken up entirely, leaving a screw under your tire with the blunt end pointing up. Even the blunt end of a screw, I think, might be able to force its way through the tread to cause a problem - possibly even after a delay, if the initial hole were relatively small. Wnt (talk) 23:47, 9 March 2017 (UTC)

@Wnt: It was a 2 1/2" Tapcon with a big hex head nicely screwed in (tip only) by a mean little pissed off tire place mechanic.--TMCk (talk) 00:26, 10 March 2017 (UTC)

Forensic detection of voice disguises

Off the top of my head, two of the most common ways to disguise one's voice are (1) changing one's pitch and (2) speaking with an accent one does not normally use. Is it really possible for forensic voice detection to penetrate these disguises? 173.52.236.173 (talk) 05:27, 5 March 2017 (UTC)

If you were using a device to change the pitch, the same device, shifting the pitch in the reverse direction, should restore the original voice. StuRat (talk) 05:30, 5 March 2017 (UTC)

... and changing one's accent will possibly fool a human listener, but will not change the characteristic volume and frequency patterns of the consonants and vowels that are common to the accents. The only reliable way to prevent forensic analysis of voice pattern is to severely degrade the reproduction until is is barely interpretable by the human ear. Dbfirs 08:28, 5 March 2017 (UTC)

This is the subject of the novel In the First Circle; you could look to see whether the technology described in the book really exists. Nyttend (talk) 12:59, 5 March 2017 (UTC)

Maybe someone should ask Q about it! 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 01:21, 6 March 2017 (UTC)

Enough random timbre/pitch/loudness/pace/background noise etc. obsfucations varying over time in a random pattern should act as sort of a one time pad right? Sagittarian Milky Way (talk) 21:47, 5 March 2017 (UTC)

Yes, "probably", but how do you know how much is "enough"? It only needs a few scattered seconds on an obfuscation that is easily reversed to allow a frequency analysis to compare with another unobfuscated recording and obtain a match. The safer method is to encode the voice digitally, then convert to a very low bit-rate so that insufficient bandwidth remains to allow an elecronic comparison. This seems to be the method used for broadcast recordings when the speaker does not wish to be identified. Dbfirs 23:21, 5 March 2017 (UTC)

I meant for each moment to be altered by many different ways and (average and instantaneous) strengths of ways, maybe going through many sequential passes before publication. Very low bit-rate compression seems much more direct and better, though. Sagittarian Milky Way (talk) 00:09, 6 March 2017 (UTC)

These sources discuss various aspects of attempting to forensicly recognise disguised voices where pitch shifting was involved, generally by the person rather than using a device [2] [3] [4] [5]. This source discusses recognising voices when accent imitation (or other disguises) were attempted [6] (this is a book chapter, perhaps other parts of the book will also be of interest) while [7] relates to dialect masking.

These sources discuss various aspects of recognise a voice where a disguise was attempted, I think they will relate to your specific questions but I'm not definitely saying it [8] [9] [10] [11] [12] (a preliminary report of that thesis is here [13]). And [14] is a word of caution on forensic voice analysis, mostly where disguises weren't used.

If that's still not enough, I also came across [15] which looks to be some sort of research proposal, perhaps you can see if anything ever came of it and [16] seems to relate to a presentation (and also includes some refs), you could see if it the research was ever published. Then there's [17] which seems to have some mention of disguise, in particular has a link to some refs including some relating to accents. And [18] is a student essay submitted to one of those essay writing sites, it seems to have a bunch of refs although I can't see where they are there.

Nil Einne (talk) 13:26, 6 March 2017 (UTC)

Continuous casting

I came across the Continuous casting article and was surprised to learn that casting was way more common than I thought. Is there any steel parts/goods that don't go through at least one casting stage? Or is casting a common step to all steel processing methods? ECS LIVA Z (talk) 06:41, 5 March 2017 (UTC)

All modern steelmaking methods involve the iron or steel at some point being melted and recast. Someguy1221 (talk) 09:25, 5 March 2017 (UTC)

The only exceptions you are likely to find are steel parts, usually daggers, made from meteoric iron or telluric iron, which are extremely rare (on Earth). Someguy1221 (talk) 09:28, 5 March 2017 (UTC)

• Steel manufacturers usually sell by the ton and deliver their pieces as ingots below the recrystallization temperature (though not necessarily at room temperature); so yes, there is "at least one casting stage". However, there are a few applications where the ingot is then heated again; see hot working (and also forging); this means the end piece will have "forgotten" the casting process (it will only ensure the correct alloy concentrations). For instance it is the case for many pieces in the in the nuclear industry, e.g. steam generators. Strangely enough I have no source for this, but it is well-known in the industry that hot forging reduces carbon inhomogeneities compared to using cast pieces. Tigraan^{Click here to contact me} 14:46, 5 March 2017 (UTC)

Extrusion or cold forming, like Cold-formed steel, is actually most common. There is also Compression molding and less common Sintering and Thixoforming. Im not shure to what extend the term casting is used international but in my country (Germany) the term casting is only used for (near) finalizing cast forming of parts, like always done with Cast iron not usually with steel. --Kharon (talk) 19:27, 5 March 2017 (UTC)

Extrusion (as the process is generally understood) isn't a process used for steel, but continuous casting (to form some sort of bar or sheet from a melt) certainly is. Maybe this is a linguistic difference, but in English continuous casting is the description used for this type of steel forming, where an unpressurised reservoir of molten steel feeds the die or mould under gravity, unlike extrusion where a mechanical force is applied to generate hydrostatic pressure.

For the OP's original question, yes, some form of casting has been part of every ironmaking process since the adoption of the blast furnace. Even if it as simple as the initial casting of pig iron. Andy Dingley (talk) 20:44, 5 March 2017 (UTC)

Starvation effect on testicles

Does semen production in the human male testicles decrease or even stop completely during long periods of starvation?— Preceding unsigned comment added by 203.112.211.106 (talk) 09:46, 5 March 2017 (UTC)

I'm surprised, but it seems not, though that depends on your definition of "long". This study starved male dogs for 10 days and actually saw an increase in sperm count. I guess evolution sets interesting priorities. I couldn't find any studies of human sperm count after starvation, probably because by the time such people get access to a doctor, that's not what's on their mind. Someguy1221 (talk) 10:13, 5 March 2017 (UTC)

Many plants can be encouraged to flower by putting them under stress - lack of water, poor soil, etc. encourage the production of flowers. It seems that the evolutionary mechanism is that when the life of the plant is at risk, the need to reproduce and scatter genes about becomes more urgent. It seems plausible that the same mechanism would apply to animals. Wymspen (talk) 15:23, 5 March 2017 (UTC)

A low protein diet may decrease libido, perhaps including semen production. Dr. Kellogg, of breakfast cereal fame, thought so: "Dr. Kellogg introduced Kellogg Corn Flakes in hopes that it would reduce masturbation." Here's a source that blames low protein and zinc levels for this effect, with low protein being specifically blamed for low availability of testosterone: [19]. StuRat (talk) 15:35, 5 March 2017 (UTC)

Feynman Lectures. Lecture 50. Ch.50-1, Ch.50-3 [20]

...

Musicians will usually speak of a musical tone in terms of three characteristics: the loudness, the pitch, and the “quality.” The “loudness” is found to correspond to the magnitude of the pressure changes. The “pitch” corresponds to the period of time for one repetition of the basic pressure function. (“Low” notes have longer periods than “high” notes.) The “quality” of a tone has to do with the differences we may still be able to hear between two notes of the same loudness and pitch. An oboe, a violin, or a soprano are still distinguishable even when they sound notes of the same pitch. The quality has to do with the structure of the repeating pattern.

— Feynman • Leighton • Sands, The Feynman Lectures on Physics, Volume I

...

We all know that a particular vowel sound—say “e–e–e”—still “sounds like” the same vowel whether we say (or sing) it at a high or a low pitch. From the mechanism we describe, we would expect that particular frequencies are emphasized when we shape our mouth for an “e–e–e,” and that they do not change as we change the pitch of our voice. So the relation of the important harmonics to the fundamental—that is, the “quality”—changes as we change pitch. Apparently the mechanism by which we recognize speech is not based on specific harmonic relationships.

— Feynman • Leighton • Sands, The Feynman Lectures on Physics, Volume I

I do not understand 2nd part. Why is the quality changed when we change pitch. Pitch is the period or frequency of the pattern (so when period doubles then the frequency of the main pattern decreases 2 times and all the harmonics frequencies also decrease 2 times). Does Feynman mean that “e–e–e”-sound has some frequencies unchanged during change of pitch? Username160611000000 (talk) 11:17, 5 March 2017 (UTC)

Harmonics of a given pitch frequency are whole-number multiples of the pitch frequency and therefore do change when the pitch changes. The first Feynman extract explains that we are sensitive to the different amplitudes of their harmonics that characterize various musical instruments. However as stated at Voice#Physiology and vocal timbre "The sound of each individual's voice is entirely unique not only because of the actual shape and size of an individual's vocal cords but also due to the size and shape of the rest of that person's body, especially the vocal tract, and the manner in which the speech sounds are habitually formed and articulated." A person's bodily characteristics that affect their voice do not change when (s)he changes the pitch of an utterance but act as a fixed shaping filter acting on the varying harmonics. Note that human Voice sounds comprise both pitch-related or "voiced" components originating in the Vocal folds and "voiceless" or non-pitch-related sounds, such as Obstruent consonants (see plosives and fricatives.) Speech recognition (see article) is different from distinguishing an oboe from a violin (for which an audio Spectrum analyzer can suffice), it includes abilities to estimate the individual speaker's identity, gender, emotional state, age, health and even their cultural background from hearing their voice. Blooteuth (talk) 12:57, 5 March 2017 (UTC)

• "Does Feynman mean that “e–e–e”-sound has some frequencies unchanged during change of pitch?" - Yes, that is exactly what he means. This is explained at formant. In short, there are frequency peaks in the spectrogram that don't change much, even when the fundamental frequency does. How and why this is the case can get as complicated as you like, but the simple fact is relatively easy to verify, and our article gives a nice table of the bits that don't change. Here is a video discussing how to measure vowel formants [21] SemanticMantis (talk) 15:16, 5 March 2017 (UTC)
  • Thanks. Can you suggest online piano simulator for testing Feynman examples (I have found one piano-player.info but it seems damper does not work as Feynman describe, there is no resonance with pressed C' and hit C)? Username160611000000 (talk) 15:54, 5 March 2017 (UTC)

Online piano simulators [22] [23] [24]. Blooteuth (talk) 22:39, 5 March 2017 (UTC)

piano-player.info - there is damper but its emulation isn't complete , because I can't hear resonance.

pianoplays.com - there is no damper option

virtualpiano.net - there is no damper option

Username160611000000 (talk) 11:30, 6 March 2017 (UTC)

I'm not sure... very high end digital pianos have routines built in to simulate String_resonance, but I'm not aware of any online. I think many of the commercial VSTis would do it, but have no specific recommendation. You may also try asking that question (an online piano with dampers and string resonance) at Reddit's synthesizer forum, [25]. Real pianos can be commonly found at public places like hospitals, universities, churches, theaters, bars. You will definitely hear these acoustic phenomena better and more clearly with a real mechanical piano, so I'd recommend trying to find one in your area to play with for a few minutes. You also might to better asking a new question here specifically on this topic. SemanticMantis (talk) 15:32, 6 March 2017 (UTC)

The Kawai CN33 digital piano has an optional string resonance function (p. 48). "Even when the sustain pedal is not depressed on an acoustic piano, the strings for any notes held will be un-damped and will resonate freely in sympathy with the strings of other notes that are played if they are part of the same harmonic series. In addition, adjacent notes will also be resonated." Blooteuth (talk) 22:58, 6 March 2017 (UTC)

• In music specifically, the other word for what Feynman is talking about here is called Timbre. --Jayron32 20:31, 6 March 2017 (UTC)

Vowels do get a lot more difficult to distinguish at high pitches around C6, though. Double sharp (talk) 11:35, 7 March 2017 (UTC)

Anatoly Dyatlov

The article states: During the accident, Dyatlov was exposed to a radiation dose of 390 rem (5.5 Sv), the equivalent to five lifetimes worth of total exposure, which causes death to 50-70% of affected persons after 30 days. — Now, what exactly is meant by "total exposure" here?--Hubon (talk) 17:41, 5 March 2017 (UTC)

My guess would be the amount of radiation an individual is exposed to, in total, over an average lifetime. --OuroborosCobra (talk) 18:48, 5 March 2017 (UTC)

Yes "in total", like "in collectiv" or "in sum". By the way, this is a very bad comparrison because since any multicellular being regenerates (and repairs) almost all its cells up to some tenthousend times during its lifespan, you can not compare that to a being that is exposed to such a high dosis in such short time that there is no chance to even regenerate a small part of all cells once. --Kharon (talk) 19:52, 5 March 2017 (UTC)

Thank you. Yet, as I see, the statement is in fact founded with a reference. Shall I remove it still?--Hubon (talk) 02:42, 6 March 2017 (UTC)

thumb|Not very healthy...

PS: While we're at it: How was this image of the Chernobyl corium – such extremly hazardous, radioactive material – created? Not by a person, right?--Hubon (talk) 05:26, 6 March 2017 (UTC)

Probably by a person, per Chernobyl disaster#Human impact: " Most of the victims were fire and rescue workers trying to bring the accident under control, who were not fully aware of how dangerous the exposure to radiation in the smoke was." That is, people did (unwisely) get sent into Chernobyl both during and after the accident for clean-up and documentation purposes. Yes, they pretty much all got very sick and many of them died. --Jayron32 15:33, 6 March 2017 (UTC)

But I mean one must be aware of the fact that what you see on this photo is corium containing the molten amalgam of the nuclear reactor itself with already used fuel elements and all its extremely radiating fission products! Thus, if really a person had taken this picture, they would have died of extremely acute radiation sickness within very short time – even just being near the actual molten core and centre of the disaster. Considering that, it's really quite hard for me to believe anybody could have stayed right by this place to take that picture... So, wouldn't it more likely have been taken by a robot or anything of that kind? (Though I doubt the Soviets [already] had such refined devices in those days...)--Hubon (talk) 16:05, 6 March 2017 (UTC)

Likely not. If you read any accounts of the Soviet response to Chernobyl, they were pretty cavalier with regards to protecting the lives of the workers sent in to clean up and document the event. While the provenance of this one picture is still unknown, it would be entirely within the characterization of the response to the event that it was taken by a person, probably only minimally protected from the intense radiation. Because we have a) no evidence the Soviets used robots for the clean up and b) we have ample evidence they used people and c) those people got sick and died in massive numbers. You[re belief in what should have happened is not relevant here. We have no reason to believe anyone except a person took that picture, a person who probably got very sick, and quite likely died. Read Wikipedia articles on Chernobyl disaster especially the text RIGHT NEXT TO the picture you posted above "volunteers in wetsuits and respirators (for protection against radioactive aerosols) and equipped with dosimeters, entered the knee-deep radioactive water and managed to open the valves." Also see Chernobyl liquidators. Those were living breathing people, not robots. That you have no belief in such people is irrelevant. They existed, and they did that work. Your incredulity has nothing to do with it. --Jayron32 16:39, 6 March 2017 (UTC)

Of course, I know about the liquidators. And you're probably right as for this picture. It's still just an eerie vision for me as a person socialized in a civilized environment that human beings were immediately exposed to this shit... Though, I do wonder if this is actually the pool that was drained by Ananenko and Bezpalov and, if yes, how the engineers in charge could tell prior to the draining mission whether the corium had already molten through the concrete floor and reached the then still water-filled pool or not — couln't find that in the article nor on the web though. Concerning the Dyatlov article, would you recommend deleting the doubtful statement we've discussed before? I'm asking because I'm really not an expert on this kind of stuff...--Hubon (talk) 02:25, 7 March 2017 (UTC)

I've already deleted it. The source doesn't say anything about five lifetimes worth of dose (and the numbers I've most recently seen for yearly dose [390 Rem/620 mRem/year = 629 years]). All the source states is some effects of high dose radiation.Tobyc75 (talk) 18:53, 7 March 2017 (UTC)

[26] while referring to the elephant foot photos says

From a safe distance, workers – or “liquidators” as they were called – rigged up a crude wheeled camera contraption and pushed it towards the Elephant’s Foot. Careful examination determined that it wasn’t all nuclear fuel. In fact, the mass consisted of only a small percentage of fuel; the rest was melted concrete, sand, and core shielding that all melted and flowed together. Over time, the Elephant’s Foot decomposed. It puffed dust and its surface cracked. But for years it remained too dangerous to approach.

Well I don't know how safe the distance was but I guess it wasn't so close to instant death. Someone else says something similar about a wheel device in the comments. Searching for such a device finds [27]

During a research trip to the sarcophagus, equipment registered levels of radiation so high that it could kill anyone who got too close for more just 300 seconds. To find the source of the daily readings, one scientist attached a camera to a wheeled device and rolled it in the direction of the source. That’s when they spotted the Elephant’s Foot—an structure so deadly that spending only 30 seconds near it will make you sick—and five minutes will kill you.

At a risk of linking to copyvio, I'm going to hope it short enough for fair use and [28] shows what I think is the device. I'm unclear exactly when the flowing photo was taken and whether it may have been taken with this device as well. [29] does suggest that the details of some of the photos are murky.

Nil Einne (talk) 01:50, 9 March 2017 (UTC)

[30] mentions we don't have similar photos from Fukushima perhaps partially because of the difficult taking them even in the modern robotics era. Nil Einne (talk) 02:02, 9 March 2017 (UTC)