mistermack

Yes, I only noticed that after I posted. Capital i is confusing, i should have used the lower case. ☺️

No, you're wrong. Both terms are used, but the common one is ID50. This is wiki article is interesting, it sheds more light on the subject, and really does illustrate how few ecoli are needed to cause infection : However, experience shows that it may be easier for the mind to compare the doses causing the effect in 50% or 1% of consumers. Here are some values of D1 (dose causing the effect considered in 1% of consumers exposed to the hazard): Escherichia coli (EHEC), haemolytic-uremic syndrome in children under 6 years: 8.4 bacterial cells; Escherichia coli (EHEC), haemolytic-uraemic syndrome in children aged 6 to 14 years: 41.9 bacterial cells; You can see from that article that it only takes 8.4 cells to infect 1% of children under 6, contrary to what Charon has been posting. To be honest, I think that proves my point. I'm not talking about 1%, I'm talking about the chance of one bacterium causing an infection, in favourable circumstances. https://en.wikipedia.org/wiki/Minimal_infective_dose#:~:text=However%2C experience shows,41.9 bacterial cells%3B

I think you and your wife are confusing "infectious dose" with what I am talking about, which is the possibility of an infection from one bacterium. It's a totally different question. The term "infectious dose" used as standard in the business refers to the ID50, which is the dose that will infect 50 percent of an average population. Of course 500-700 cells is more likely, in that case. But that says nothing about the potential for one bacterium, in the right circumstances, being able to replicate and cause an infection. I know that I read or heard that one strain of ecoli can, under the right circumstances, cause a harmful infection from a single bacterium. I didn't dream it, it was from an informed source, but of course I didn't note it at the time as I didn't anticipate ever discussing it. This link is interesting. The first post is from someone who works in the field : Quote : " That said, I spend all day every day studying bacterial pathogens, " and : In this case, it depends on the particular species of bacteria you're talking about. Some species can cause an infection from just a couple of bacteria; others can need hundreds (or more!) in order to reliably infect a host." It's not a paper, it's a discussion, but it's the sort of thing that I'm talking about. The source that I remember made it clear that this strain of ecoli is highly unusual in being able to cause infection from such a small initial dose. https://www.reddit.com/r/askscience/comments/1go68r/can_i_get_sick_from_a_single_bacteria_cell_or/

One single bacterium can become 16 after four replications. And a possible 128 after 7. So what stops the process, in the case of a single bacterium, in a person with low acid levels in their stomach?

The thing with ecoli is that it can survive and multiply in the gut, which is how one bacterium can be dangerous. I can't remember where I read that, but it did include the info that people with lower levels of acid in the stomach are especially vulnerable. And that includes people who take acid suppressors, including Omeprazole, which I take, one a day. That's what made it stick in my memory.

While I’m pretty relaxed generally about food hygiene, there are a few bacteria that really do need to be avoided. I think the worst is an ecoli variant found in cattle dung. I remember reading that it is so bad, that a single bacterium can lead to a fatal infection. Most viruses and bacteria need a fairly substantial number to invade in the first infection, but for some reason, this ecoli bug can do it with just one. So if I dropped a bottle cap in a house, I wouldn’t worry, but if I dropped it in a farm yard, I would be very wary.

That's been calculated many times. The limiting factor is the effect on the inner ear, causing nausea for some people. From memory, the answer is 224 metres. At that size, an orbital period of 30 seconds gives 1g artificial gravity, and no humans experience nausea. You could go lower than 224m and experiment with drugs for the people who feel nauseous, or go for slightly less than 1g, so the 224m isn't a fixed point, but anything over that would be ok. That sounds like a big space station, but it could be just two balanced units, with a 224 metre tether, rotating opposite each other. But anyway, in the distant future, it's likely that 224 metres would be on the small side. If a station is to be self-sustaining, it would have to be a lot bigger than that. So long term, I don't think size will be any kind of obstacle. But short term, it will be.

I would be a bit cautious about making dust out of leaves. It would be wise to avoid breathing in any of the dust at least. A friend of mine caught legionnairs and very nearly died, from breathing in spray from jet washers. They used a pool of standing water as a reservoir. You never know what you are breathing in, it's best to take precautions.

It's an interesting thought, the engineering of a spinning space station. On earth, the main building materials need to be strong in compression, whereas in a spinning space station, you want materials that are strong in tension. The lack of weather should be a plus, and storage space will be limitless, and heavy lifting will be very different.

This does push back the age that can confidently be attributed to homo sapiens, although there are other finds that are now being dated as even older than this, to about 300,000 years ago. It's a blurry picture, because it seems likely that there was quite a bit of inbreeding with neanderthals, on various occasions. This site in Morocco, Jebel Irhoud, seems to be even older, but dating and classification are maybe not as certain as the Omo site. The remains are classified as homo sapiens, but there looks to be some neanderthal element, in the tools and some features. https://en.wikipedia.org/wiki/Jebel_Irhoud

But what is a sex change operation, if it's not making gay people straight? You start with a man who is attracted to men, and the objective is to end up after the operation as a woman who is attracted to men. The objective is the same, to end up as a straight person. I made it clear that giving hormones doesn't work at the moment, I said it was a flippant thought, but whether there will be techniques to change sexual orientation in the future is a different story. Who thought fifty years ago that it would be possible to give a man a pig's heart? If there's a demand for it, they will certainly try it. It has a horrible history, because of the compulsion element, and the pretty awful things they tried. But that applies to most other procedures in medicine too. But if that's what some people genuinely want, and it brings them happiness, then for them it would be a good thing. Just because it would not be for you, doesn't mean that it should be denied to others if that's what they really want.

To begin with, you could, as now, have the first space stations orbiting within the Earth's protective shield. Then later, as stations got bigger, you could have the plant-growing surfaces situated on the outside facing in, so that the moist soil would be absorbing the harmful stuff. Obviously, that would be way down the line, on huge self sustaining space stations. Anything bulky that needs storing, like the water supply, could also be positioned on the outer surface. Maybe a station could generate it's own magnetic shield, a mini version of the Earth.

Wouldn't it be better and less invasive to use silicone implants on the hips, or fillers or a combination of the two? In any case, the size of the hips isn't exactly a deal breaker, when it comes to sex differences. There are plenty of very attractive women with narrow hips, and vice versa. I'm a male, and I have wide hips, but I've never (till now) even thought about it as a sexual marker. It's quite hard even for an expert to say for certain that a skeleton is of a man or woman. They usually say which it is most likely to be.

Admittedly, I wasn't thinking about pandemics when I posted. A beverage cap doesn't strike me as a serious hazard. Even if somebody else handled it, they would normally touch the outside parts rather than the parts that contact the drink. Hand washing would normally protect you from the odd stray virus picked up off a cap. With the covid outbreak, the consensus medical opinion seems to be that the importance of hand washing is not very great, compared to mask wearing and ventilation. Other bugs are more easily passed on off surfaces so hand washing does make sense, especially around hospitals and other public places. As far as the OP goes though, I would say that soap and water are more than enough for that kind of situation. A bit over the top, if anything.

How did the human species evolve, without soap and bleach? It's a mystery. If we could see what our ancestors had to eat at times, to survive, we might be a little less fussy these days. There is some very nasty stuff out there, but that doesn't mean that it's all bad. And our immune systems are tuned to dealing with loads of bacteria and viruses and may need regular exposure to keep healthy.

I've heard that too. It's a possibility, but I would say that it's not likely to be first or second choice, because with the current technology, there's very little to be gained on Venus. It's too hot on the surface, and there's not much that's useable in the atmosphere, which is also very corrosive. Venus would be a great candidtate for Terraforming, having close to 1g gravity. But it would be an enormous project. Probably far too much for the available gains. I don't think Jupiter itself would have any useable resources, but it's moons would. Our own Moon would be easier to exploit though, because the sunlight is stronger here, so power generation is easier.

When it comes to the insignificance of humans, it's obviously a comparative thing, not absolute. In absolute terms, humans are truly insignificant in both size and lifespan. Most of us are only significant to close friends and family. A few are significant historically, but most of that is in a bad way. The bad make more history than the good.

The new cases in the UK have been dropping now for six days, it looks like the peak of the Omicron spike has passed. Unfortunately, the deaths look like they are in the sharply rising phase, matching the beginning of the Omicron spike. If that's the case, then it seems to indicate that Omicron is certainly a killer, maybe at a lower percentage, but it's certainly capable of having an effect on the death figures. It would help, if the government would release a breakdown of the death figures, showing what strain of Covid was involved.

I've posted this before, but I still believe that the future of humans away from the Earth is in space stations, not planets or moons. Once you get them up to a certain size, you can rotate them and create 1g of artificial gravity, you have virtually limitless free energy beaming at you, and you can land and take off using practically no fuel whatsoever. You can mine the moons for raw materials, you can use the cheap solar electricity to manufacture everything, you have free cold storage, and space is well and truly limitless. Here on Earth, we are running out of space with seven billion humans. Up there, there is room for seven billion billion humans, without stepping on each others toes. That is by living on space stations. I would imagine that the first stage in colonising space would be a Moon mining operation, with a space station orbiting the Moon as permanent living quarters. I don't think Mars or the outer planets would become any use for hundreds of years. The first step would be to establish a settlement that was self-sustaining without help from Earth. And that's a formidable step, but should happen within a couple of hundred years.

You need to be even more specific than that. It depends what kind of colony you are talking about. A working colony of adults would probably cope with the low gravity fairly well. The record stay on the space station is 437 days, but that's effectively zero gravity. With the substantial gravity on Mars, one might guess that you could stay fairly healthy over five to ten years. A breeding colony would be a totally different story. Nobody knows how children would develop, in Mars gravity. I can't see how it will ever be ethical to try it. I suppose you could take some chimps there, maybe a few pregnant females, and observe the development. But my guess is that it will never be ethical to do it with humans. (not exactly ethical with chimps). I've often thought that Mars might one day be a great place for a retirement colony. When you get really old and feeble, a lower-gravity environment might be a great option.

Plastic? Glass?

What problem? I agree, Mars has a high gravity problem, as far as human use is concerned. It takes a huge amount of energy to take off from Mars. Not as bad as the Earth, but huge nonetheless. The Moon is far easier. The Apollo missions could take off and get home with very little fuel.

That's not how science works. Things that don't work today can work tomorrow. Changing inclination has a lot of bad history, because of compulsion and brutish treatment that didn't work, but that doesn't mean that in the future it will never work and be a welcome option to some people. Although it might turn out to be impossible, who knows? But you can bet your life that it will be tried again in the future, it might even be happening now. I absolutely didn't say that. I said that i thought it's unlikely to happen, and gave my reasons, for others to chew up as much as they like. I may well be wrong in that. Discussion doesn't mean just hearing what you want to hear. What's the point of that? Considering the downside is just as important as the upside in real life. Cosmetic surgery doesn't have a 100% rosy history either. It's been fantastic for some people, but an absolute disaster for others. Trans surgery can be likewise. I have a good friend who had the full works, and is still not sure whether they regret it, or not, after several years.

Afraid not, that's why I just said "I remember" to make it clear. I wasn't collecting references 25 years ago, or buying peer reviewed journals. But if you remember the turn of the millenium differently, that's fair enough. From what I remember, you didn't need a peer reviewed paper to get on tv or in the papers at the time. It was a time of anything goes, and little criticism. This is the site I use for facts about ice : http://nsidc.org/arcticseaicenews/ Their long term graphs show little change over the last fifteen years, averaged out, although it's still possible to make the case for a continued downward trend in the Arctic ice. If you take the last fifteen years in isolation, the trend looks pretty flat, but if you add on the previous fifteen years, it looks like an ongoing drop.

It's probably a bit early, but I have a feeling that the Omicron wave has peaked in the UK. The reporting of cases and deaths has been a bit intermittent over the Christmas/New Year period, but it's seemingly back to normal now, and the new cases have apparently began to drop. Only a few days, but it's better than nothing. I would be really interested to know what's happened to Delta cases, since the Omicron virus became dominant. It would be great to know if the new variant suppresses the spread of the old one, or just adds to the total over the top. PS, glad you had a mild dose Beecee, and hope you don't get any lingering after-effects.