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49

You must tell facts from fiction; viruses need living cells to replicate, because they do not have the molecular machinery at hand to generate energy and construct building blocks essential to life. So no, viruses cannot bring back the dead or revitalize dead cells. The thing that comes close to it are zombie ants. These ants have been infected by a ...


19

The immortal jellyfish can revert back to its immature polyp stage after reaching maturity, then mature again, over and over. You can read more on the wikipedia page, but this ability means it can potentially avoid senescence altogether.


13

Snopes.com gives a discussion of possible issues with the original experiment. Evaporation or bowel or body movements for instance. I think the biggest complaint about the experiment is that it has not been reproducible and that the original experiment was flawed. MacDougall only took six measurements and he threw two of them out in his original work. ...


12

Long story short, the astronaut probably wouldn't make it, and would first loose consciousness then suffocate. There is a lot of myth and hollywood dramatization regarding this kind of thing. Here are some: You will explode. This is just ridiculous. The skin is air tight (relatively speaking). It is also very elastic and can pull and bend quite a great ...


10

Yes, it can, but it is extremely rare. ... nosebleeds are rarely fatal, accounting for only 4 of the 2.4 million deaths in the U.S. in 1999 [1]. The main issue is that epistaxis can be a sign of potentially fatal diseases: The instances in which nosebleed is potentially fatal are those in which there is a history of recent head injury, severe ...


9

Nope, you wouldn't die instantly. While explosive decompression has never been tested on humans (for obvious reasons), the dangers of a vacuum have mostly to do with the pressure differential between your body and the now pressure-less void around you. The most fragile parts of the biological system would be the lungs and ears, and the instantaneous ...


9

About 52 to 74 days according to hunger strike wiki page. This wiki page bases its data on 8 persons who died due to hunger strike: Days survived by each person: 66, 59, 61, 61, 61, 46, 71, 73, 62, 60.


7

There are multiple levels of memory, some of which would die immediately, some of which would take some time. So the answer is: it depends; some immediately, some only very slowly. At the highest level, the current neuronal firing state of the brain encodes memory on a very short scale - working memory. The memory held on this level does not have a clear ...


7

Note: This answer is a complement to @Christiaan's answer, and is partly reusing stuff from this related answer. Since you are specifically asking about viruses, I thought that it might be interesting to mention that similar behaviour changes as those mentioned for fungi can also be caused by viruses. See e.g. this quote from Roy et al. (2006): In ...


6

This would vary a LOT depending on the amount of stored fat, previous diet, the weather and even the water drunk. Weeks though there is a good chance that a loss of electrolytes can cause health problems. (that's why I mention the water you drink, because many bottled water brands and wells have a bit of salt in them.) Its hard to say from anecdotal ...


6

One other important event that can kill the person is that the atmospheric pressure on Mars surface is less than one percent that of earth at ground level. Suddden exposure to extremely low atmospheric pressure will immediately release dissloved gases within blood and and other body fluids as bubbles and the individual is likely to get a very severe form of ...


6

Any injury, that results in external bleeding can lead to death, since it is a breach in the body's defenses and an entry point for pathogens. Explanation: When you have nose bleeding the blood must be coming from somewhere. Usually from inside your body. That means there is a hole in your body which is big enough for blood to stream out. That in return ...


6

Two compounds are specifically associated with the smell of decaying cadavers (Hoffman et al., 2009), namely: 1,5-pentanediamine (cadaverine), and 1,4-butanediamine (putrescine) Cadaverine is produced by breakdown of lysin and putrescine by the breakdown of ornithine (Science ME). Both are nitrogen-rich compounds and particularly pungent-smelling. ...


6

I don't exactly know what you meant to say by "non-functional". Red blood cells are delivering oxygen to tissues, but they cannot do this anymore in the lack of blood flow. White blood cells degenerate and after about 84 hours are no longer existing as cells (Babapulle CJ, Jayasundera NP, 1993). Neutrophiles degenerate first and lymphocytes last. Platelets ...


6

Second law of thermodynamic and ageing The second law of thermodynamic applies to closed system. Organisms are not closed system. The second law of thermodynamic is a fundamental principle of our universe and any biological processes do follow the principles of physics. However, stating that biological ageing is (partially) caused by the second law of ...


5

You will be hard-pressed to find any scientific data on this question. Psychology in humans is already a difficult study, at times failing to demonstrate results with real scientific rigor. When studying animal psychology, you face another substantial barrier - language. Although some primates have been taught to communicate with sign language, the best of ...


5

The issue I suspect you are struggling with is the anthropomorphization of the evolutionary process. Evolution is an optimization process driven by random mechanisms...i.e. there is often not a "reason" for why certain things are the way they are. Evolution is not a conscious "designer" that produces things with a specific goal in mind...it simply "picks" ...


5

Although both involve DNA fragmentation, the pattern produced is very different. During apoptosis, DNA fragmentation is done in a regular, controlled pattern, which if run on a gel produces a characteristic "ladder" pattern. Necrosis, on the other hand, is a more stochastic process, and will produce a smear. This details the difference rather nicely, ...


5

You have a very interesting question there! In order to answer, however, we must examine the most widely accepted "reason" for why we age and eventually die. Most scientists agree that it is because of mass cell death. Normally you and I would be able to deal quite well with mass cell death (such as a very large injury), the problem comes in when we are ...


5

A good working theory is that this is caused by Rigor Mortis and the anatomy of insect legs. In most cases, the muscles that pull the leg down (or closer together) are larger than the ones that pull the leg up. This is because those muscles (flexors) must support the insect's weight: (Click for larger view) When the muscles contract after death, the ...


4

This is very dependent on the organism within each of the groups you mention. While for the most part, archea are the extremophiles and have the ability to withstand many extreme conditions, nutrient limitation survival greatly varies. I think you could easily find organisms in each group that could withstand nutrient limitation well. A good example would ...


4

Alain Bombard He is a french biologist who voluntarily tested how many days a man can survive drinking seawater and how? Biologist point of view Sea contains ~3.5% of salt$^1$. Our kidney separates the waste from water and excrete them in urine provided the salt content is less than ~2%.$^2$ So, it will take the water already present in the body. ...


4

Yes. Usually only in the case of someone with hemophilia (no blood clotting) but it could theoretically occur with any serious uncontrolled nosebleed. Since blood in the stomach tends to cause vomiting, you could also lead to a scenario where someone who was uncomfortable with blood would pass out due to being scared of the blood and then aspirate (puke and ...


4

The actual paper that the linked article cites never mentioned about freezing the crickets: We examined CCR (Chill Coma Recovery) in G. pennsylvanicus exposed to 0 °C. The time required for crickets to recover movement of the abdomen and legs increased exponentially with the duration of exposure to 0 °C; after more than 12 h of cold exposure, ...


4

Yes. Moreover, even if they were not urinating at the time of death, they likely would at death, assuming adequate filling of the urinary bladder. There are two sphincters that close off the urethra. One is under control of the autonomic nervous system and the other is voluntarily controlled (somatic). At death, both sphincters will relax, releasing the ...


3

I think the key is "his fragrant corpse." When an animal dies and begins to rot, a number of quite smelly chemicals are given off, including putrescine and cadaverine. Crows and other carrion birds like vultures are probably very sensitive to these compounds, rather like sharks are to the smell of blood.


3

Yes it can but it is very rare. Most often when you get a nosebleed it is either a vein or capillary that ruptures. However in some cases it is arterial bleeding which is always an emergency. I have honestly noticed when I have nosebleeds often each one is worse than the previous with some having a lot of bleeding but still no gushing from an artery. ...


3

For car crashes, it's a mixed bag: Better Better Worse Worse Basically, it looks like, if wearing a seat belt, slightly overweight is more likely to survive a car crash, but if no seat belts are worn they are at a disadvantage; the very obese are always more likely to die, however. Also, some of this was found only for males, not females.


3

I very much doubt it. You may however die from whatever's causing the pain. The reason you feel pain is so you stop doing whatever is causing the pain. Hence someone knows not to touch a hot fire because it is painful. But the pain itself is not actually the danger - it's the fire burning away skin. So pain is actually a good thing, a survival mechanism. So ...


3

Less then a minute breathing in the atmosphere (and a very painful death). Mars' atmosphere is >95% CO2 with only trivial O2. These are atmospheric conditions similar to those used to euthanize laboratory animals. He probably wouldn't even make it 200 meters before suffocating.



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