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Questions tagged [death]

A state in which an organism or a cellular system, as defined by its full set of functionality, ceases to exist (i.e., most of the functions are irreversibly lost).

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1answer
37 views

Do dead bivalves always float in water?

This 2014 Oct 14 article by Jolene Bouchon avouches: How do you know if your bivalves are alive? Immediately get rid of anything with broken or damaged shells. Clams and mussels shells should be ...
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Mammal Statistics about Natural Death Versus Being Killed?

Is there data determining what percentage of mammals die a natural death (disease, old age) and what percentage die due to being killed and/or eaten by other mammals? In watching wildlife ...
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Is there a physiological reason why direct lightning strikes are not lethal for everyone or does it all come down to dumb luck?

Some people who get directly struck by lightning and some more than once (starts at 00:25) survive while others die instantly or later on due to complications/injuries. Looking at a wiki page for ...
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Typical concentration of oxygen for hypoxia and necrosis due to lack of nutrients

I'm a physicist and I'm interested in hypoxia due to the lack of nutrients at the center of avascular tumors. So I have a few questions about hypoxia. Below which concentration of oxygen and other ...
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How do booklice avoid dessication?

I often find booklice (aka psocids) in old paper notes I have in semi-storage. These pages of paper are intentionally left in dry conditions on my desk to avoid damage. However, if the psocids live ...
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Where can I find resources of the biological processes occurring after death of a mammal at various temperatures?

Using google I usually end with results in cell death. I found some layman articles, but that does not help. My main interest is the brain part.
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What's the decomposition rate of a mammal at -20 Celsius? [closed]

Is there any where to predict it without thawing? In terms of measuring it. What if the body was immersed in sugar prior to freezing?
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Why exactly does the immune system weaken with age?

Why does the immune system become weaker with age in humans and in some other mammals? Let's try to be more specific than just "everything degrades with age."
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Why can't we kill ourselves by holding our breath?

Is it possible to kill yourself by holding your breath? This question is obviously copied from Quora, but I had heard it as a fact that we cannot kill ourselves by holding our breath and I'm looking ...
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395 views

Immediate cause of death due to dehydration

When we don't drink we get dehydrated and after some time we die. What is the cause of death on the lowest level? I would assume the dielectric properties around/in the heart tissue get imbalanced ...
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What is the death mechanism of an electrocuted Mosquito?

While using the Electric bat, does the mosquito get killed by primary electrocution, or it secondarily by burning?
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5k views

Why do eyes change colour after death?

Why exactly do eyes turn black when we die? (Or even change colour at all). The source of inspiration to this question is due to this video https://www.youtube.com/watch?v=6mNs_TcUyHc&t=627s (it's ...
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790 views

Why do living things go belly up as they die? [closed]

I have seen birds, lizards, frogs, fish, etc in various places on their back dead. May be insecticides cause them to flip over but I do not believe every upside down creature died by poison as stated ...
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73 views

What is the fundamental reason for death from too high or low internal temperature?

I have read something about why we die from over/underheat, but always found too general reasons. Such that the liver fails. But why does the liver fail? I would like to know the most fundamental ...
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490 views

Do dead cells always contain no nucleus?

If I examine a dead cell, can I be sure that it has not a nucleus? And what about the other organelles?
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86 views

How to surpass cell death?

Is it possible to surpass/decay cell death. For example to disable the process muscles cells death, by tweaking the transduction pathways: If it's not possible in our age Medicine, what it would ...
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257 views

When is a person declared to be dead?

From what I can tell, it is not well defined, but at least in the US it has to do with cessation of cardiopulmonary functionality. Any reliable sources that give a definition of when a human being is ...
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Is it possible for a human to live forever if he/she didn't catch any diseases?

Aging is not a disease, but it's the gradual weakening of the body, as the body gets weaker it gets more prone to diseases. So one doesn't die from aging but from diseases. So if one didn't catch any ...
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279 views

Will neurons die if they are inactive for a long time?

We know that when muscles are not used they atrophy. Does something similar also happen in neurons if they do not receive any stimulus?
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491 views

What is the medical definition of death?

What is the medical definition of death? And how do medical examiners determine whether a person has really deceased, as opposed to for example a condition like brain death?
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174 views

Which extinction event killed the highest proportion of organisms?

The P-T extinction (a.k.a. the Great Dying) tends to be considered the worst - for example, Wikipedia states: It is the Earth's most severe known extinction event, with up to 96% of all marine ...
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88 views

Decomposition of human body after death

What causes decomposition of human body after death? Here it says autolysis, while Here it says that bacteria decompose the body. If bacteria decompose the body, why don't they do while we are living?
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Do ants really dispose of their own dead, and how/why?

I just read this from Wikipedia's Swarm Behavior article: Despite the lack of centralized decision making, ant colonies exhibit complex behaviour and have even been able to demonstrate the ability ...
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Alternative conditions for Liquifactive Necrosis

A person is beaten on the head hard enough to swell the whole front part of the head. The body is thrown into the river and recovered after about 36 hours. Is this condition enough for liquifactive ...
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What is operating temperature of the human brain?

I've heard several times that human brain can die in temperatures over 40 °C, or under 10 °C, as an engineer I'm curious. In what temperature region can brain properly work? And just an underlying ...
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Does mechanical shock kill animals?

I heard that loss of blood kills shot animals, a lot. But a few times, I heard that mechanical shock kills animals. For example in this video (starts to play at the right spot; relevant from 14:35 to ...
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At what point is a picked flower considered dead?

Let a flower be picked from the ground such that its stem is cut and the (a?) flower is separated from the root system (as in figure). Questions: 1a. At what "point" is it considered dead? Does ...
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Aging and death of perennials

Perennial plants species generate a new plant annually from the same parent root stock. At the end of the year that new shoot withers and dies, to re-appear the next year. Hence, the above-ground ...
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2k views

Can rigor mortis change the anatomical position in which a person died?

I've been told as an undergrad in anthropology that the flexed position of the body in which some Neanderthal skeletons were found indicates that they were deliberately buried. Apart from the good ...
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1answer
803 views

How long do tiny spiders live? [closed]

I'm pretty sure there's a spider in my ear. I feel it move and hear the scratching (i blame my cat for playing with bugs in the bed). I've gone to the doctor, but all they do is flush my ear with ...
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how long after death can a body exhibit an immune response

I suppose this is part of a larger question - at what point do the body's coordinated systems (Endocrine, Autonomic nervous system etc) begin to fail? Within hours? Days? Minutes? Of course this ...
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1answer
606 views

How does glutaraldehyde kill bacteria?

How does glutaraldehyde kill bacteria? After disinfecting, does it leave the corpses of the bacteria to count? Does it leave bio-film in tact?
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1k views

Single celled organism and immortality

My biology book says: No individual is immortal,except single celled organisms.. I think that such conclusion aries from the necessity of binary division in many single celled organism to ...
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816 views

What causes drone bees to die?

... when not killed by other members of the hive. Is it always a consequence of exile (denial of some resource, etc) or does some organ fail regardless of circumstances?
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381 views

Does an increased reproduction/mortality rate provide an evolutionary advantage?

If a species has a high mortality/birth rate, then it is able to adapt to changing environments more quickly than species that live for a long time. Without a high mortality rate, food and other ...
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1k views

What would kill you first water or cola? [closed]

After discussing this with some colleagues, I devised the theory that you could drink more coca-cola in a single sitting than you could water, without killing you. Defining the volume it would take ...
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Does reproduction cause aging ? Is aging just a strategy to increase reproductive success in all organisms? [closed]

Background for why I am asking this: I read a book—modern biological theory and experiments on celibacy— which uses life history theory to imply that reproduction is the reason why organisms grow old....
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957 views

Which are the last cells of the human body to die?

When somebody dies, which are the last surviving cells of his/her body? Those of hair, nails, or some other obscure but resilient cells? Shedding light on why and how they are so vital might boost ...
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1answer
5k views

Why does fever above 102 herald a cancer patient's death?

I was recently intrigued by a longtime hospice nurse's observation that her cancer patients die a different death than her Alzheimer's, multiple sclerosis, heart failure and COPD patients. She stated ...
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I know why phototaxis happens but why did those bees die? [closed]

There is a tube light in front of my veranda. This is just spring. So at night when I turn on the tube light many bees gather around the tube for phototaxis. But in the morning I see many of them are ...
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What Would Happen To a Human Who Died In Space And Stayed There For a Prolonged Period of Time? [closed]

Last night I was watching a documentary regarding the Apollo space program, and it spoke about how Apollo 8 orbited the moon 10 times then came back to Earth. It said that while the ship was in orbit ...
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2answers
514 views

Metabolic activity postmortem

I read some papers about studies on metabolism in post-mortem tissues in human, but I do not exactly the reason about why our brain continues to have activity after death.
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2k views

Would urination continue after death?

If someone was urinating, and they were to hypothetically suddenly "fall dead" (the brain is unconscious and all muscles / organs are unfunctional), would they continue urinating or would it stop?
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557 views

What are most common natural causes of death? [closed]

What are most frequently occurring natural causes of death?
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106 views

Could a single cell be brought to life?

If a scientist is observing a single cell under a microscope, and then realizes that the cell has died, is it possible to bring that dead cell back to life? For my inquiry, let's assume that the ...
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4k views

Can tardigrades survive being eaten?

Compared to a tardigrade, the cockroach seems fragile. But can tardigrades survive the acidic environment of being eaten by most animals?
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Can the dead be brought back to life by viruses?

Zombies have been a part of popular culture for decades. The living dead rising up to take over the world is a terrifying concept, worthy of Hollywood blockbusters and television hits. Some of those ...
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12k views

What is the maximum altitude where humans can survive?

What is the highest altitude that a human can survive without being pressurized? Let's assume that oxygen and heat/insulation are not the limiting factors? Why I asked.
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978 views

Does the second law of thermodynamics cause aging? [closed]

What is the current understanding as to why organisms age and die? In the following explanation on Ask an Engineer, entropy is not even considered (despite it being answered by an engineer). Unless ...
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1answer
12k views

What happens to blood after a person dies?

After a human dies, what happens to their blood? I know that it tends to accumulate in the lower areas of the body, whichever parts are closest to the ground, but I am wondering about coagulation. ...