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December 26

Comparison of RNA vaccines and RNA viruses

How do they compare? Can the former reproduce, at least to some degree, once inside the human body? Some of the latter cause cancer, how can we discard that the former also won't? Is their mechanism of action similar? Both articles might improve with a sub-section around these issues. --Bumptump (talk) 14:40, 26 December 2020 (UTC)[reply]

You should read the respective articles. Ruslik_Zero 17:16, 26 December 2020 (UTC)[reply]

Always a good idea, but do they address the specific questions posed by the OP? --Lambiam 23:36, 26 December 2020 (UTC)[reply]

As implied above, the articles need more content regarding these questions. Ruslik should read the respective articles to see by himself. --Bumptump (talk) 23:51, 26 December 2020 (UTC)[reply]

The last two paragraphs in 'Mechanism' section answer all your questions. Ruslik_Zero 20:23, 27 December 2020 (UTC)[reply]

They describe how the vaccine is intended to work. They do not contain an assurance that no RNA replication can take place. If they somehow imply this, well, then this implication is rather... implicit. I can understand that people want to be sure that this cannot happen. Assurances by scientists saying, "trust us, nothing can go wrong", are probably not an effective approach. Note also that until November 27 the lead stated that the cells are "reprogrammed" by injecting the vaccine, which was not helpful. --Lambiam 23:52, 27 December 2020 (UTC)[reply]

Sure, some scientists can have trouble communicating to the general public because they tend to forget not everyone has their level of background knowledge. An RNA vaccine would have to include an RNA-dependent polymerase or something like a retrotransposon to even hypothetically get a cell to make copies of the RNA. "Typically", gene information only moves one-way in cells, DNA to RNA to protein. Free RNA is rapidly broken down by cells. The central challenge of RNA vaccine development has been actually getting the RNA to persist in a cell long enough to get translated, which was done with the modRNA technique (which is on the Main Page today), selectively modifying the RNA so it's more resistant to degradation but still able to get translated by ribosomes. --47.152.93.24 (talk) 02:14, 28 December 2020 (UTC)[reply]

And some respondents here can have trouble communicating with questioners, dismissing reasonable questions as if they display an unconscionable ignorance and this reference desk has no raison d'être other than to belittle questioners. --Lambiam 12:15, 28 December 2020 (UTC)[reply]

The intent of existing RNA vaccines is to get the RNA into your cells and get it translated by ribosomes into the protein it codes for. Whether that counts as "reproduction" is up to you. This is where we run up against human language being vague. Viruses themselves are just nucleic acid and proteins in a package, and don't do anything outside of a cell, which is why many people don't consider them really "alive". Oncoviruses can cause cancer by trying to insert their genes into the cell's DNA or by otherwise messing with gene transcription and regulation. Doing the former requires enzymes to splice the viral genes into the cell's DNA (retroviruses use a reverse transcriptase). The latter could potentially be caused by just RNA, but it'd probably have to be complex RNA encoding things like ribozymes. This could potentially be used to treat cancer or other diseases as well. But for producing immunity to a disease, the vaccine will generally only contain genes for antigens to elicit an immune response against them. The RNA vaccines for COVID-19 just contain the gene for the viral "spike protein" that binds to cells to infect them. --47.152.93.24 (talk) 03:21, 27 December 2020 (UTC)[reply]

December 28

Covid-19 vs. Spanish Flu, who would win?

Spanish flu had far more fatalities, but that has to be at least in part because treatment possibilities were a lot worse then. There were no ventilators, no antibiotics or antivirals, etc. Like if you compared a mass shooting (50 people struck by bullets, say) in 1918 to one in 2020, the 2020 one would have far higher survival rate because of blood transfusions and antibiotics (making wounded people much less likely to die of infections), even given identical guns for both shootings. You couldn't conclude that the 1918 guns were deadlier.

So is there a reasonable way to compare the virulence of a Covid-19 infection to a Spanish Flu one, given comparable levels of treatment? Similarly, what about the transmissibility? Any idea how the comparison would end up? Thanks. 2601:648:8202:96B0:0:0:0:313A (talk) 00:30, 28 December 2020 (UTC)[reply]

Sociology and epidemiology and psychology and it's just a flu bro people (1918 had them too) are too complex to know for sure without controlled time travel trials of many permutations of years, Covid, Spanish flu (only one per timeline) and patient zero events. Pick lots of different plausible people to be patient zeros and see what happens. To research who are plausible patient zeros start out with using your time machine to find out who was the real patient zero and how did he get it? Did he eat a bat or got bit by one or bit the head off or raped it or what? Find out how easy it is to become patient zero from each method (i.e. what kind of bat eating mishap, can you get it from kissing, how often do humans kiss bats vs drink bat blood vs touch it with an open wound vs breathe bat germs vs..), find out how much viral load you get by the different methods and where the precursor virus lived and things like that and develop a non-distorting unbiased distribution of patient zero events. Like an electron cloud of patient zeros, an electron cloud for each year and germ combination. Account for bat phenotypes too and so on to make sure you replicate the butterfly effect just right instead of favoring one result or the other by choosing to make the bat sneeze at millisecond 3 instead of 10 too often or making the average human a bat zoosadist too rarely or too often or whatever without knowing the real odds. That would be playing God instead of just finding out which virus is worse in an apples-to-apples comparison. Also this trial's unethical.^{[citation needed]} Sagittarian Milky Way (talk) 00:47, 28 December 2020 (UTC)[reply]

On second thought maybe it is simpler to just make the random mutation dice non-deterministic in the progenitor virus species or strain instead of "it's deterministic cause it already happened" and let the patient zero chips do whatever happens. Repeat till you get many epidemics of each type and make a graph of ppm of Earth killed by badness percentile and see which looks worse. Sagittarian Milky Way (talk) 01:38, 28 December 2020 (UTC)[reply]

Hard to give a reference for this one, but it may be possible to say something useful.

First, Spanish flu hit at the worst time imaginable, which must be part of the reason why it's so infamous: right at the end of World War 1. Millions of soldiers were travelling around the world, spreading the virus, millions had been breathing diluted poison gas for a few years and even in European countries that stayed neutral, trade disruptions led to food and fuel shortages, so people were in a pretty bad condition.

I've read in newspapers and seen on tv news that about 10% of covid patients who end up in hospital in my small western European country die within a few weeks. At the same time, only about 0.2% of all people who get infected die, which means that about 98% recovers without significant treatment (although note that some patients die without ever getting to hospital, but those are the people who were expected to die anyway, even if they hadn't had covid). Those number seem to match with numbers reported for excess deaths and some signs of saturation, indicating that in some areas everybody has already been infected. If covid had struck in 1923, those 98% would have recovered too. It appears that Spanish flu mortality was higher than 2%. In the early 20th century, the population was younger, suffered less from welfare diseases (like obesity) and was more used to infections (which keep your immune system in shape), so was less sensitive to covid (but also to some extend to flu). And back then, it was considered normal that elderly people would die of pneumonia.

All combined, I guess that if covid had struck in 1923 (when the effects of WW1 were waning off), hardly anyone would have noticed. And maybe it did, as there are several coronaviruses that now only cause a common cold, but when first appearing would have been as unknown to our immune system as the current virus is now. But if Spanish flu hadn't struck in the aftermath of WW1, it wouldn't have been as bad as it came to be.

Note that I'm not a virologist or epidemiologist, although my understanding of history and statistics isn't worse than theirs. PiusImpavidus (talk) 10:54, 28 December 2020 (UTC)[reply]

The Spanish flu killed the strong immune systems, usually the young not the old. Sagittarian Milky Way (talk) 15:18, 28 December 2020 (UTC)[reply]

If the Spanish flu had struck in 1923 instead of 1918, it might have been a mere blip on the radar (but note that the similar 2009 swine flu pandemic was recognized as an outbreak in Mexico well before it became a pandemic). I am not convinced that this would also have been so for COVID-19, if only because of the suddenness of the transition from mild symptoms to a life-threatening situation as well as the long-lasting effects experienced by some recovered patients. I think there are too many unknowns to compare the respective virulences in a 1918 what if scenario. --Lambiam 12:48, 28 December 2020 (UTC)[reply]

Perhaps worth reminding everyone that although it's commonly referred to as "Spanish flu," epidemiologists are fairly sure that it didn't originate in Spain, nor was it particularly prevalent there. Because many of the countries in which it first spread were in the the throes of WW1, their newspapers were censored to avoid damaging morale: Spain was neutral in the war, so Spanish newspapers freely reported the disease's progress in Spain, leading to a false impression that it had appeared there first. {The poster formerly known as 87.81.230.195} 2.122.56.237 (talk) 14:39, 28 December 2020 (UTC)[reply]

Kansas flu or Chinese flu? Sagittarian Milky Way (talk) 15:18, 28 December 2020 (UTC)[reply]

How does Gravitational waves discovery useful in daily life?

How does Gravitational waves discovery useful in daily life? This discovery made three people won nobel prize in 2017. Rizosome (talk) 15:47, 28 December 2020 (UTC)[reply]

To make sure there aren't hostile aliens communicating to each other with gravitational waves, at least waves above our detection limit. Maybe they'd use gravitational waves or neutrinos cause they're hard to detect. If many more gravitational waves than is plausibly a natural frequency occur with no natural explanation that may be bad, especially if they appear to coding for something. Like evenly distributed small gaps of no gravitational waves when graphed by some aspects which would be ambiguous bits or trits or tetracontaits or whatever. So ruling that out is comforting in addition to the astrophysical knowledge gained. Sagittarian Milky Way (talk) 16:23, 28 December 2020 (UTC)[reply]

There is no need for it to be useful, see basic research. Fgf10 (talk) 16:45, 28 December 2020 (UTC)[reply]
The winners of the Nobel Prize must have conferred a great "benefit to humankind". It is not further defined how to make that determination. --Lambiam 00:35, 29 December 2020 (UTC)[reply]

Knowledge itself is a great benefit. Fgf10 (talk) 09:20, 29 December 2020 (UTC)[reply]

So the title of the novel The Faculty of Useless Knowledge contains an oxymoron. --Lambiam 12:56, 29 December 2020 (UTC)[reply]

Also learning this science required pushing the envelope of laser length accuracy and orthogonality and interferometry and the technology invented to find the waves may have practical benefits in other applications that will be invented in the 21st century and might not even be thought of yet. If you already know how to do it when the applications are invented in the future you won't have to waste time learning how to do it cause the envelope has already been pushed. Sagittarian Milky Way (talk) 00:59, 29 December 2020 (UTC)[reply]

It is useful to our modern lives by not having any use at all, thereby diverting resources that we would otherwise use in a destructive way. Count Iblis (talk) 07:47, 29 December 2020 (UTC)[reply]

And it keeps people at work and off the streets who otherwise might become hooligans or street robbers. --Lambiam 14:10, 29 December 2020 (UTC)[reply]

That's it. As I always said to my kids during their formative years, "You've got two choices, boys. Either become hooligans or street robbers, or go and discover gravitational waves. There's not much in the middle, frankly." -- Jack of Oz ^{[pleasantries]} 21:52, 29 December 2020 (UTC)[reply]

When did GPS satellites launched in space?

When did GPS satellites launched in space? I didn't find any information about in this article. Rizosome (talk) 16:03, 28 December 2020 (UTC)[reply]

Actually, the article says "with the first prototype spacecraft launched in 1978 and the full constellation of 24 satellites operational in 1993." Mike Turnbull (talk) 16:25, 28 December 2020 (UTC)[reply]

That's the first generation, there have been replacement launches of new generation satellites pretty much continuously ever since. The last one was last month, see List of GPS satellites.Fgf10 (talk) 16:44, 28 December 2020 (UTC)[reply]

It was definitely usable at some level in 1982, as I did a project with Ferranti on it then. That implies there must have been 4 satellites at least. Greglocock (talk) 20:53, 28 December 2020 (UTC)[reply]

What's the difference between photovoltaic and photoelectric effect?

What's the difference between photovoltaic and photoelectric effect? Wiki says they are closely related. Rizosome (talk) 16:58, 28 December 2020 (UTC)[reply]

From the lead of the Photovoltaic effect article:

The main distinction is that the term photoelectric effect is now usually used when the electron is ejected out of the material (usually into a vacuum) and photovoltaic effect used when the excited charge carrier is still contained within the material. In either case, an electric potential (or voltage) is produced by the separation of charges, and the light has to have a sufficient energy to overcome the potential barrier for excitation. The physical essence of the difference is usually that photoelectric emission separates the charges by ballistic conduction and photovoltaic emission separates them by diffusion, but some "hot carrier" photovoltaic device concepts blur this distinction.

-- ToE 19:09, 28 December 2020 (UTC)[reply]

December 29

UV-C sanitizing machine that works against the covid?

I've been considering getting one of these, so I can disinfect things like my keys, mobile phone, cards, money, masks (if I only wore them briefly), cigarettes, stuff that came in the mail, documents related to my work, etc.

Unfortunately I've heard that there are a lot of scams and products that are just crappy on places like eBay and Amazon.

What do I need to be looking for, to find one that actually kills the covid/China virus/corona/whatever? I know it needs to be a purpose-made UV-C emitter, not just a general ultraviolet tube/blacklight - apparently scammers are selling these at inflated prices and advertising them as working against the virus.

Are there any specific products/manufacturers that are recommended? --Iloveparrots (talk) 10:30, 29 December 2020 (UTC)[reply]

Don't buy the LED models, as they are probably just pale blue lights. UVC LEDs are a very special product, not likely to be sold cheaply. I bought a UVC fluoro tube. It is a clear tube with no fluorescent coating. It produces ozone, which you can smell, when it operates. I got it before the outbreak, so there was no shortage. Graeme Bartlett (talk) 12:20, 29 December 2020 (UTC)[reply]

Is it true that most of those handheld UV wands are useless blue lamps - and if they're not useless, they're actively dangerous, as the intensity of UV-C required to kill the covid would also hurt your eyes and blister your skin? Not something you should be waving around. Saw that claimed. --Iloveparrots (talk) 12:59, 29 December 2020 (UTC)[reply]

Let me quote from ultraviolet germicidal irradiation: "For human beings, skin exposure to germicidal wavelengths of UV light can produce rapid sunburn and skin cancer. Exposure of the eyes to this UV radiation can produce extremely painful inflammation of the cornea and temporary or permanent vision impairment, up to and including blindness in some cases." Draw your own conclusions. Fgf10 (talk) 15:01, 29 December 2020 (UTC)[reply]

As this is the reference desk, let's try a reference: UV Lights and Lamps: Ultraviolet-C Radiation, Disinfection, and Coronavirus. Quick summary: mostly does not work, easily causes more harm than good, but the definitive science is not in yet. Unproven medical interventions are usually not a great idea. 85.76.64.226 (talk) 17:09, 29 December 2020 (UTC)[reply]

Does Rabies virus harmful to dog also?

I know Rabies virus harmful to humans, what about dogs health? Rizosome (talk) 18:07, 29 December 2020 (UTC)[reply]

I googled "does rabies kill dogs" and the answer is definitely YES. Before they die, they can become aggressive (hence the term "mad dog") and bite, which is one way humans can get it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:18, 29 December 2020 (UTC)[reply]

Untreated rabies is almost always fatal in humans, dogs or any other mammal. Cullen³²⁸ Let's discuss it 18:20, 29 December 2020 (UTC)[reply]

See Rabies in animals. Deor (talk) 18:48, 29 December 2020 (UTC)[reply]

vaccination after COVID 19 infection

If somebody is unknowingly infected w/ Covid 19, and then the next day, while stil presymptomatic and still in the incubation period, they receive the first dose of vaccine, would their recite of the vaccine be expected to have any effect on their subsequent course of illness with COVID 19? Please note, I am not seeking medical advice for myself as I am months away from vaccination. I am merely curious because I have heard that for some other viral diseases, ( measles , Hepatitis A) vaccination within a certain amount of time after exposure can sometimes prevent or at least reduce severity of illness. — Preceding unsigned comment added by 63.247.53.11 (talk) 20:55, 29 December 2020 (UTC)[reply]

Not known, but looks less likely with Covid, because the virus has a very rapid onset and is in full bloom before a vaccine would normally be expected to raise a response. https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html Gzuckier (talk) 06:13, 30 December 2020 (UTC)[reply]

Just now I saw a news story of someone who developed symptoms and tested positive for COVID-19 six days after getting the vaccine.^[1] It is possible they were already infected but still asymptomatic when receiving the first dose. Alternatively, they could have become infected afterwards; the protection of the vaccination before the second dose is rather limited. The story does not mention anything concerning the prognosis of the patient. While the prior vaccination will at least somewhat boost an immunological response, for some COVID-19 patients the worst problem is the immune system overreacting in a so-called cytokine storm. --Lambiam 15:57, 30 December 2020 (UTC)[reply]

December 30

Cryogenic freezer at Monterey aquarium

[2] The Aquarium has kindly lent one of its two cryogenic freezers to a nearby hospital for storage of Covid vaccine, and it made a nice news story. Not answered is: why does an aquarium have something like that around anyway? The vaccine apparently must be stored at -94 degrees F, so the freezer has to be even colder than that, and in the photo it looks pretty big (it has to hold 1000s of vaccine vials). I'm sure the aquarium has a perfectly good use for the freezers but I can't help puzzling over what it might be.

Also, are there any serious technical challenges to building lots of such freezers out of parts on hand, as part of Operation Warp Speed? It seems strange that there should be a big shortage. It's just ordinary pumps and compressors at that temperature, right? No special magnetic whatevers like liquid helium temperatures would require. Thanks. 2601:648:8202:96B0:0:0:0:313A (talk) 04:50, 30 December 2020 (UTC)[reply]

As to the second question, see ULT freezer and Refrigerator#Ultra-low temperature refrigerators for the requirements. It does seem like something that could be built largely "out of parts on hand", but if course you'd have to make sure that those parts were usable at the applicable temperatures, and you'd need a suitable low-temperature refrigerant.

The articles also indicate that such freezers are used to preserve biological samples, so if the aquarium is doing zoological research, that'd probably be why they had them. --174.95.161.129 (talk) 05:33, 30 December 2020 (UTC)[reply]

Storage of proteins & enzymes, cells, DNA and RNA, and a few other things works best at -70°C or lower, so materials the Monterey Bay Aquarium uses for research or veterinary care purposes probably require ultracold freezers. You probably can't cobble together a -70°C freezer out of a random assortment of pumps and compressors, though, since there are only a few manufacturers and ultracold freezers tend to run around $15,000 US for the most inexpensive models - I'd imagine if they were easy to build more manufacturers would do so and the price might be lower. Wevets (talk) 05:58, 30 December 2020 (UTC)[reply]

Thanks all. I didn't realize that an ULT freezer is different from a cryocooler. However, it sounds like ULT freezers are expensive mostly because they are specialized lab equipment: they are basically normal refrigerators with two compressor stages without any exotic materials. Ramping up production during this past year (say some tens of thousands of extra ones are needed) even at $15k each would be in the $100mm's somewhere, not that huge an amount in the overall Covid response. It was interesting to see that Stanford University had 2000 of these freezers in 2010. 2601:648:8202:96B0:0:0:0:313A (talk) 01:57, 31 December 2020 (UTC)[reply]

Great responses above. Just a quick note on availability of spare parts. It's certainly possible, but one of the issues is that most refrigeration systems are built to foodservice specs and they don't require anything near that temperature. Even ice cream, which is typically the lowest-temp food item, only requires -20F for commercial storage (and honestly 0F is more common). So, most "off the shelf" components are built to that standard. Even the specialized trucks ice cream manufacturers uses only get down to -20F (ref) and simply include more insulation and barriers to maintain the temperature. This limits the user-pool and the sheer numbers. Matt Deres (talk) 16:32, 1 January 2021 (UTC)[reply]

Healing from cuts ability

Gonna preface this with a statement that this isn’t a medical question, I don’t have any cuts or anything, I’m just wondering a couple of things. So, if you get cut your blood scabs over it then it heals, by growing new skin, and bigger cuts take longer right? Does this scale linearly over the whole body? Does it even scale locally? Say if I had a 2cm cut on my left hand would it heal faster than 2 1cm cuts one on either hand? Does the body prioritise healing beyond what areas have the most blood flow? Where can I read up on this? --86.172.59.180 (talk) 23:14, 30 December 2020 (UTC)[reply]

Wound healing: The larger the wound, the more work it takes to repair it, because the cells have to regenerate the whole area and join back together the wound margins. Larger wounds will usually entail more damage to structures like blood vessels, and those need to regrow as well. As far as I'm aware, the body doesn't "centrally control" wound healing anywhere. Cells migrate to the wound in response to inflammation, and the wound healing is regulated by local signalling between cells. --47.152.93.24 (talk) 03:06, 31 December 2020 (UTC)[reply]

Here's a paper describing constant speed traveling waves of cell propagation in response to wounding. It's an in vitro model, though. JoelleJay (talk) 19:46, 31 December 2020 (UTC)[reply]

December 31

Multi-shot vaccines

It's in the news that the first few Covid vaccines require two shots a few weeks apart, but there are some other multi-shot vaccines, including shingles (2 doses), rabies (3 or more doses), etc. Apparently the Pfizer Covid vaccine is two shots of the same drug, taken a few weeks apart (for some reason that hadn't occurred to me: I thought it would be drug A and then later drug B, like two-part epoxy). My questions:

In these multi-dose vaccines, are the doses always of the same drug?
Are there many other common vaccinations where more than 1 shot is involved?
What happens if you get the prescribed number of doses, but for whatever reason the time between doses is longer than recommended? This is particularly with regard to Covid, so since the RCT didn't address this question, any sort of reasonably science-based info is welcome (nobody should take it as medical advice, they should always follow the protocol as closely as they can, but it won't be entirely within anyone's control, so I'm asking what's likely to happen if something goes wrong).

My reason for asking the last question is there are N doses of Pfizer vaccine available at a given time, and current policy has been to vaccinate N/2 people with their first shot, then save the remaining doses to give the second shot to the same N/2 people on schedule. But now they are talking about switching to a policy of delivering the first shot as fast as they can (i.e. use the N doses for N people) and do the second shot as more vaccine becomes available. Since there will undoubtedly be slips and delays in some places, lots of people will get the second shot later than expected, or not at all. So I'm wondering the likely public health consequence of this. 2601:648:8202:96B0:0:0:0:313A (talk) 01:33, 31 December 2020 (UTC)[reply]

Following the approval in the UK of the Oxford/Astra Zeneca vaccine, there has been considerable debate about such timing issues. "This BBC article". discusses this and the present UK government's conclusion that it is better to give the N doses to N people (rather than N/2) when the initial supply is limited, mainly because that gives at least some protection and there is a fairly wide time window for the second dose. Mike Turnbull (talk) 13:09, 31 December 2020 (UTC)[reply]

The official UK line is that "For both vaccines [Pfizer and Oxford/Astra], data provided to MHRA demonstrate that while efficacy is optimised when a second dose is administered, both offer considerable protection after a single dose, at least in the short term... The Joint Committee on Vaccination and Immunisation (JCVI) has subsequently recommended that as many people on the JCVI priority list as possible should sequentially be offered a first vaccine dose as the initial priority". [3] Professor Chris Whitty, the Chief Medical Officer for England, recently quoted a figure of "at least 70% protection" from an initial dose. [4] Alansplodge (talk) 14:40, 1 January 2021 (UTC)[reply]

Administering two shots is common for the MMRV vaccine and a recombinant zoster vaccine, and routine for several others, such as the hepatitis A vaccine. For mRNA vaccines such as those developed to offer protection against COVID-19, the mRNA coaxes the recipients' cells into producing antigens. If the antigens of two different vaccines are sufficiently similar, which means that the antibodies developed by the recipients' immune systems cross-react to the other antigen, it would seem quite likely that using these different vaccines for the two shots still offers enhanced protection. The proof should be given by clinical trials, which have not been conducted. If the second shot is delayed for too long, it will quite possibly not offer as much enhanced protection as when it is given timely. Again, clinical trials would be needed to determine the impact for these specific vaccines, but have also not been conducted. --Lambiam 13:20, 31 December 2020 (UTC)[reply]

Gam-COVID-Vac requires two different drugs for its two doses. Ruslik_Zero 12:18, 1 January 2021 (UTC)[reply]

Need assistance identifying these satellite images on the covers of three editions of Oxford Atlas of the World

The Atlas of the World published by Oxford University Press has been updated with new edition released annually for more than twenty years. All the recent ones each has a satellite image as its cover. I was able to identify the sources for most of those images with ease using TinEye but there are three that I have not been able to including:

I would like to know what those satellite images are from or if not, at least what geographical location each is depicting. StellarHalo (talk) 11:58, 31 December 2020 (UTC)[reply]

Why not write to the OUP and ask them? --174.95.161.129 (talk) 04:34, 1 January 2021 (UTC)[reply]

Well, I could but they would probably say something along the line of "the information you request is in those books. you can purchase them online in here and here". Also, the main reason I am asking here is because gaining direct access to those books fore free is currently tedious due to the pandemic lockdowns. StellarHalo (talk) 06:22, 1 January 2021 (UTC)[reply]

You won't know until you try. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:47, 1 January 2021 (UTC)[reply]

The 16th edition could be looking east across the Horn of Africa? (just south of the tip - see this) PaleCloudedWhite (talk) 19:56, 1 January 2021 (UTC)[reply]

January 1

Onion ring - Bispropenyl disulfide?

Hi all,

I have a little look around and the only mentions of this purported chemical seem to be quotations from Wikipedia.

Disulfide obviously means two Sulfurs in the middle.
"Propynyl"... a three carbon alkyne with a triple bond between the carbons?
Bis is an nonstandard form of di, so two "Propynyl" as the R's in R-S-S-R.

Hmm.... would Carbon triple-bonds survive cooking temperature? And is Bispropenyl disulfide - despite all what you might see on the internet - pretty much fictional? Pete AU aka --Shirt58 (talk) 12:37, 1 January 2021 (UTC)[reply]

The compound is more commonly called Diallyl disulfide. Propene is an alkene not an alkyne. Mike Turnbull (talk) 13:09, 1 January 2021 (UTC)[reply]

The term occurs in the old-fashioned spelling "bispropenyl disulphide" in an article in New Scientist. It contains an illustration with the chemical formula. I am not too familiar with the representation of chemical formulas, but I think this is not the same as diallyl disulfide: the double bonds are at different spots:

CH₃–CH=CH—S–S–CH=CH—CH₃ (bispropenyl disulfide)

CH₂=CH–CH₂–S–S–CH₂–CH=CH₂ (diallyl disulfide)

--Lambiam 17:39, 1 January 2021 (UTC)[reply]

Nice spot, Lambiam. There are a number of similar components in onion and the one named by the OP is indeed likely to be one of the isomers you drew (the double bonds can each be independently E or Z but usually Z, I think). There is a freely-available article that covers some of these compounds here: Eady, Colin C.; Kamoi, Takahiro; Kato, Masahiro; Porter, Noel G.; Davis, Sheree; Shaw, Martin; Kamoi, Akiko; Imai, Shinsuke (2008). "Silencing Onion Lachrymatory Factor Synthase Causes a Significant Change in the Sulfur Secondary Metabolite Profile". Plant Physiology. 147 (4): 2096–2106. doi:10.1104/pp.108.123273. PMC 2492635. PMID 18583530.. Mike Turnbull (talk) 18:13, 1 January 2021 (UTC)[reply]

Looking with "Find Similar Structures" for diallyl disulfide on PubChem turns up a compound with the IUPAC name1-(prop-1-enyldisulfanyl)prop-1-ene, with as a given synonym "dipropenyl disulfide". The two appear to be sufficiently different that the former has three safety warnings, including "acutely toxic", while the other has none. As far as I can tell its chemical structure is the same as seen in the New Scientist article, which mentions this as responsible for a "sweeter smell" when frying onions, so I think this is the compound referred to as "bispropenyl disulfide" in the Onion ring article. --Lambiam 19:57, 1 January 2021 (UTC)[reply]

What are candidates for the decade with the most weather records under various emissions scenarios?

Or only the limited set of all-time single-station records that most weather stations of long recordkeeping have, just count them and sum worldwide, that's simpler than trying to estimate complicated things like what year the world hurricane speed record etc is most likely to fall.

A spherical cow model doesn't seem too hard if you used some simple "what's the highest sigma reached by year x if weather station starts 1900 and climate didn't change" model which has probably been made and statistically found the most likely year to break a record if each temperature was boosted by the y-value of a simple curve that fits the average land temperature curve in the IPCC scenario but a degree of global warming doesn't necessarily cause 1 degree of boost to the highest temperatures in a place and correlation with precip, cold records etc would be bad. And those would have more effect than heat records by (collectively) outnumbering them. Sagittarian Milky Way (talk) 15:08, 1 January 2021 (UTC)[reply]

How to understand pitch in sound subject?

I can understand "volume", but I can't understand "pitch" term. How to understand pitch in sound subject?Rizosome (talk) 15:22, 1 January 2021 (UTC)[reply]

We have an article at Pitch (music) - does that help? Matt Deres (talk) 16:35, 1 January 2021 (UTC)[reply]

See also This YouTube video for an basic explanation. Alansplodge (talk) 16:46, 1 January 2021 (UTC)[reply]

Small children speak at a higher pitch than adults. Adult women generally speak at a higher pitch than adult men. On a standard musical keyboard such as a piano the keys go left to right from a low pitch by small steps to a high pitch; the sounds produced differ only in pitch. --Lambiam 17:02, 1 January 2021 (UTC)[reply]

Wiki articles are too technical for readers so I prefer reference desk to learn. Low Pitch means first key in piano? Rizosome (talk) 18:31, 1 January 2021 (UTC)[reply]

The lowest pitch on a piano is the key farthest to the left; the highest pitch is the key farthest to the right. The pitch increases from left to right. --R. S. Shaw (talk) 20:15, 1 January 2021 (UTC)[reply]

If you find the Wikipedia articles too technical, try the Simple English Wikipedia.--Shantavira|^{feed me} 20:35, 1 January 2021 (UTC)[reply]

(edit conflict) Low and high are relative attributes, just like tall and short. A man with a height of 240 centimetres is tall, but no one would call a tower of that height tall. The leftmost key of a standard piano (corresponding to the key with key number 1 in this table) is close to the lowest pitch humans can hear as a tone, but many pipe organs have a pedal keyboard that goes even lower. The pitches of whale songs can also be lower. But sounds that have a much and much lower pitch than the highest key of a piano may still be referred to as having a high pitch, and sounds that have a much higher pitch than the lowest key may be referred to as having a low pitch, because they are high or low in comparison to something else. No human singer, not even Diana Damrau, can get as high as the highest key on a piano, and not even Yuri Wichniakov can get as low as the lowest key, and still here we read: "A Basque woman recently performed this remarkable shout for me. She started with a loud, high tone and gradually descended to a low pitch."

By the way, there is also a Wikipedia written in a simpler English; see for example their article about Pitch. --Lambiam 20:49, 1 January 2021 (UTC)[reply]

So "low pitch" sounds like "low decibel" sound? Rizosome (talk) 23:48, 1 January 2021 (UTC)[reply]

No. Decibel, as a measure of sound pressure level, relates to loudness or volume. Pitch relates to that character of a musical note which is independent of its duration. While our article -- pitch (music) -- describes the mechanism, the perception or qualia is difficult to put in writing, other then by referring to sounds you may have heard -- such as the low pitch of a key on the left side of a piano (YouTube: Hear Piano Note - Lowest A 0m20s) vs. the high pitch of a key on the right (YouTube: Hear Piano Note - Highest C 0m7s) (Here are notes in ascending pitch: YouTube: Hear White Piano Keys - All 52 Notes 2m45s.), or the low pitch of a foghorn (YouTube: Sounding the Sumburgh Foghorn 2m22s -- first sounds at 1m45s) vs. the high pitch of a penny whistle (YouTube: Traditional Irish Tin Whistle Songs 2m51s).

If you are deaf or sufficiently hearing impaired to not discern these difference, let us know and we might be able to give an analogy, otherwise here are some additional videos on the subject:

YouTube: Sound Waves: High Pitch and Low Pitch 2m32s -- demonstrates with voice, guitar string, xylophone, and resonate bottle.
YouTube: Pitch – Higher and Lower 3m14s -- a quiz comparing pairs of piano notes. (A non-interactive demo video of an interactive program.)

You may find dog whistle interesting; its pitch is above that which most humans can hear. -- ToE 00:48, 2 January 2021 (UTC)[reply]

Why nuclear fusion instead of breeder reactors

Dear Wikipedians:

Why are so much attention and effort being directed towards nuclear fusion when breeder reactors are already shown to work? I read a piece by Bernard Cohen which calculates that just the amount of uranium-238 alone (not counting thorium) is enough to power the world for as long as the sun is in a state to support life on earth.

172.97.139.62 (talk) 23:57, 1 January 2021 (UTC)[reply]

For something as big as what will end Earth's clean energy shortage it's good to not put all eggs in one basket. Sagittarian Milky Way (talk) 00:06, 2 January 2021 (UTC)[reply]

Safely disposing of radioactive waste is an unsolved issue. Breeder reactors produce less than other types of fission reactors, but if applied on a grand scale, the waste will become a growing and eventually unmanageable problem. --Lambiam 01:58, 2 January 2021 (UTC)[reply]

The amount of available fuel is not currently a limiting quantity - there is little practical difference to a contemporary society between using uranium to run FBRs for a billion years or the same uranium to run LWRs for 10 million years. Moving beyond the issue of fuel, the breeder reactors really only have one thing going for them - the waste consists of isotopes with much shorter halflives than that of conventional nuclear reactors. But that is where the major advantages end. Breeder reactors currently require a greater capital investment than conventional reactors of similar output; they are more prone to accidents, which is a rather huge deal when it comes to nuclear; and it's theoretically possible to use a breeder reactor to generate fuel for nuclear weapons. It seems likely that the increased cost and accident risk may be a sort of self-reinforcing issue - i.e. that the existence of these issues may contribute to more conventional reactor designs receiving more attention and research moneys, causing the difference in cost and safety to persist regardless. Anyway, fusion power comes without concern for the kind of radiation leaks of either of these types of fission reactor, without the concern of massive quantities of radioactive waste, and without the concern of waste being turned into fission bombs. Someguy1221 (talk) 11:29, 2 January 2021 (UTC)[reply]

January 2

Silvery shiny inside of bags with chips

Bags with chips often have silvery shiny inside. Why is this and how is this done? A thin layer of metal like aluminum? Thank you. Hevesli (talk) 11:14, 2 January 2021 (UTC)[reply]

This is a metallised film, manufactured by exposing a polymer, such as cellophane, to metal vapor that has been injected into a vacuum chamber. This process is known as physical vapor deposition. Someguy1221 (talk) 11:40, 2 January 2021 (UTC)[reply]