Wikipedia:Reference desk/Archives/Science/2020 May 14

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May 14

How many SARS 2 "organisms" are in someone when they die? What is their mass and density?

Sagittarian Milky Way (talk) 01:23, 14 May 2020 (UTC)

Think the question should be worded how many Covid organisms are enough to make a person sick, and how many are enough to kill a person. 67.175.224.138 (talk) 02:28, 14 May 2020 (UTC).

The number of individual organisms in a body overpowered by 'SARS 2 organisms' or required to kill an individual will vary with the individual. A person with an ongoing illness - say of the heart or liver or diabetes - will require less organisms to overpower them. Similarly an older person of 50 kilos (110lbs) would probably require less organisms than a younger person of 120 kilos (265lbs). One then has to take into account gender, race or age for example. Based on these variables the answer is going to vary. All this is apart from what method would be used to measure the mass and density of pathogens present in a body.Richard Avery (talk) 12:58, 14 May 2020 (UTC)

• We can do a Fermi estimate by looking at the fact that there is about 60 grams of DNA in your body right now, and viruses are mostly DNA with a protein coating. There are about 3,000,000,000 base pairs in each strand of DNA and Covid 19 has about about 30,000 base pairs, which is about 10^-5 the amount of DNA in your body, so IF every single cell in your body was infected, the DNA from the coronavirus should weigh about 0.00060 grams. DNA base pairs have a mass of about 650 daltons, and the current coronavirus has a mass on the order of [https://www.cusabio.com/2019-novel-coronavirus.html 5,500,000 daltons), meaning that DNA is about 1/10,000 the mass of the virus. That means that IF every single cell in your body was infected with it, the total mass of all of the coronavirus particles would weight about 60 grams, or 0.1% of your weight. That would be an upper limit, and since MUCH less than "every cell in your body" would be infected, you can expect the actual percent of mass to be several orders of magnitude less. --Jayron32 13:41, 14 May 2020 (UTC)

A bit of data from a Lancet article: "The viral loads in throat swab and sputum samples peaked at around 5–6 days after symptom onset, ranging from around 10⁴ to 10⁷ copies per mL during this time". doi:10.1016/S1473-3099(20)30113-4 The approimate average volume of a human is about 65 L, so that means if every mL of you is as infected as saliva, you have 6.5x10⁸ to 6.5x10¹¹ viral particles. DMacks (talk) 15:36, 19 May 2020 (UTC)

What are the biggest living organisms that are without a nervous system?

What are the current biggest living organisms that are without a nervous system? --ThePupil (talk) 10:36, 14 May 2020 (UTC)

You need to say what you mean by "creature". Bazza (talk) 10:57, 14 May 2020 (UTC)

Right. I changed the term. Thank you.--ThePupil (talk) 11:19, 14 May 2020 (UTC)

As is often the case, Wikipedia has an article which should answer your question. Looks like it's a tree. Bazza (talk) 11:34, 14 May 2020 (UTC)

Oh! By organisms, I mean organisms which do not belong to the plants, but something with movement. I'm not sure what is the right term for it. --ThePupil (talk) 12:10, 14 May 2020 (UTC)

Well, the same article should tell you what you want to know. Bazza (talk) 13:15, 14 May 2020 (UTC)

Plants have movement, by the way. Movement is often one of the defining characteristics of "life" --OuroborosCobra (talk) 13:36, 14 May 2020 (UTC)

They just move very slowly, compared with animals. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:43, 14 May 2020 (UTC)

Not all of them. And animals are comatose compared to some fungi. Bazza (talk) 14:25, 14 May 2020 (UTC)

Thank you. Except for plants, are there other living from the animalia kingdom who doesn't have nervous system? --93.126.116.89 (talk) 14:57, 14 May 2020 (UTC)

A candidate for the biggest animal without a nervous system is this sponge, said to be the size of a small minivan. Mikenorton (talk) 15:19, 14 May 2020 (UTC)

(EC) I don't entirely understand your question as plants are not in the animalia kingdom. And fungi, that are mentioned above, are neither plants or animals and also lack a nervous system. (While classification of eukaryotes, as with any diverse group, is difficult, and some place animals and fungi in the same group e.g. Opisthokont, animals and fungi are still different groups within those groups AFAIK.) But if your looking for animals without a nervous system I suggest you read that article and Evolution of nervous systems. Sponges (possibly a monophyletic grouping) are generally regarded as having no nervous system. Nil Einne (talk) 15:32, 14 May 2020 (UTC)

And you then come up against the question of whether a massive sponge is one organism or a large colony. --Khajidha (talk) 01:12, 15 May 2020 (UTC)

Also, what do you mean by nervous system? Jellyfish have a diffuse neural net. Does that count?--Khajidha (talk) 01:14, 15 May 2020 (UTC)

Basically I searched for any kind of information about any kind of organism (that isn't plant or fungus) that doesn't have a nervous system. By nervous system, I mean to any kind of innervation. If I'm not mistaken, I've heard in past that there are some worms or nematode which don't have a nervous system, but I'm not sure if I understood it well.--ThePupil (talk) 18:20, 15 May 2020 (UTC)

All sources seem to agree that the only animals completely lacking a nervous system are the sponges. On the other hand there ist this roundworm that doesn't uses neurons to feed: its pharynx contracts rythmically and ingests the bacteria the worm feeds on without need for neural input. But there are three neural circuits that stop the feeding and cause the worm to spit if it risks to ingests someting harmful, see [[1]] 2003:F5:6F08:8200:351A:656A:496C:6A58 (talk) 13:52, 17 May 2020 (UTC) Marco PB

You're choices are rather limited. Count Iblis (talk) 19:29, 17 May 2020 (UTC)

Immortality Research

I was curious if there scientific institutions or organizations which seek to develop methods to allow people to either live very long or achieve some form of immortality. I have heard about the cryogenic research which is conducted in some countries, but cryogenics are not life-prolonging in themselves, at least not as far as I know. The idea seems to be that if a corpse is frozen, that it could be brought back to life in the far future.--2A02:1205:5049:A1D0:C837:56F9:23F:C686 (talk) 19:01, 14 May 2020 (UTC)

You could start by reviewing Ageing. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:10, 14 May 2020 (UTC)

Also, the articles Indefinite lifespan and Strategies for Engineered Negligible Senescence might be of interest to you. You can also take a look at the Aubrey de Grey article. Futurist110 (talk) 23:03, 14 May 2020 (UTC)

Young blood transfusion if you are into vampire chic. 2601:648:8202:96B0:3567:50D5:8BFF:4588 (talk) 07:18, 16 May 2020 (UTC)

Can a person who had coronary artery disease and a heart attack in their early 50s (and survived) live into their 80s and beyond?

Can a person who had coronary artery disease and a heart attack in their early 50s as a result of having their arteries be clogged with plaque (and survived this heart attack as a result of going to the hospital and getting their arteries unclogged in time) live into their 80s and beyond? If so, just how likely is this to occur? It this very unlikely to occur? Or are the odds of this occurring more likely than one thinks? Futurist110 (talk) 23:02, 14 May 2020 (UTC)

I know someone who had a heart attack before 40 and is now 73, so maybe you could ask again in seven years? —Tamfang (talk) 00:54, 15 May 2020 (UTC)

The answer is yes, this is perfectly possible, if the person maintains an solid exercise regime and a healthy well balanced diet. It is not only possible but has happened on multiple occasions, too numerous to name. 86.186.232.80 (talk) 10:05, 15 May 2020 (UTC)

Without even looking, I can almost certainly say that a person has had that happen at some point in the 10,000 years of humanity, given the tens of billions of people who have lived and the wide variation in their stories. It could even be more than one, so one could even use the word "people" in that place and be truthful. --Jayron32 14:26, 15 May 2020 (UTC)

So, just to make the point, here's one person who survived 43 years (at the time of writing) after his first heart attack. Here is someone who has survived, so far, 42 years after his first heart attack, and he's had several since then. He's still alive today. Here is someone who doesn't quite make your criteria, but he's close. He had his first heart attack at 52, and was 78 at the time of writing the article. Based on those, we can definitely say that it is more than a person who has done as you have described. It is definitely people who have done so. --Jayron32 14:32, 15 May 2020 (UTC)

It is possible, of course, but unlikely as ischemic heart disease is a progressive disease. Ruslik_Zero 21:01, 15 May 2020 (UTC)

• This article works out a probability model for your question and using the given equation, or eyeballed-numbers from Figure 1F, one can work out the odds of the person dying at any particular age (keep in mind the obvious caveats of extrapolating the model to non-US population, and applying it to any individual patient). Abecedare (talk) 22:34, 15 May 2020 (UTC)

See here. Count Iblis (talk) 18:42, 16 May 2020 (UTC)