April 13[edit]

At what air temperature on average dogs start to stick out their tongues and at what they start to keep them inside mouth? 212.180.235.46 (talk) 18:21, 13 April 2024 (UTC)[reply]

According to this source, the air temperature surrounding the animal must not rise above 29.5°C (85°F). The same article mentions 31°C (87.8°F) as the skin temperature; at higher ambient temperatures panting becomes the only available means by which the dog can cool itself. Normal human skin temperature is a few degrees higher, so you may still be comfortable while your hot dog is not.  --Lambiam 21:15, 13 April 2024 (UTC)[reply]

Long experience tells me it varies a lot by breed and even by individual dogs. I'd be fascinated if anyone has ever worked out an average. HiLo48 (talk) 23:33, 13 April 2024 (UTC)[reply]

I would think it would also depend on the dog's activity level, i.e. whether running around or just setting. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:40, 14 April 2024 (UTC)[reply]

For sure. HiLo48 (talk) 01:21, 14 April 2024 (UTC)[reply]

Hm, I've seen dogs panting during walkout well below 29.5°C which looks quite high (at around 20°C or so). 212.180.235.46 (talk) 11:09, 14 April 2024 (UTC)[reply]

I imagine there are local factors and a lot of diversity. The dog that scammed his way into my house is quite heat intolerant apparently having forgotten his young wild days in a hot eucalyptus forest, whereas the semi-feral street dogs seem unbothered by temperatures like 34C while bathed in IR from concrete etc. Sean.hoyland (talk) 11:30, 14 April 2024 (UTC)[reply]

April 16[edit]

Understandably they need to be hot to fly well but something must be different. Protein differences? Sagittarian Milky Way (talk) 18:58, 16 April 2024 (UTC)[reply]

Some possible answers here. Mikenorton (talk) 19:21, 16 April 2024 (UTC)[reply]

How do chickens live for 5-10 years with average body temperatures of 105-107? With smaller breeds over 106. Sagittarian Milky Way (talk) 00:51, 17 April 2024 (UTC)[reply]

That article says a lot about how active birds are, but some are not terribly active at all. Eagles glide and soar with seemingly minimal energy input. Unless under threat (which is rare), Australia's large ratites spend the day strolling around or just sitting. Other Australian birds just seem to sit on tree branches all day, only very occasionally making a very short foray for food. HiLo48 (talk) 03:18, 17 April 2024 (UTC)[reply]

Their defense against pathogens is presumably dependent to some extent on maintaining high core body temperatures, or having very elevated temperatures in bursts like bats. Is a temperature difference of a few Celsius between us and chickens that much of a challenge for biological systems? Many social insects operate at much higher temperatures. Sean.hoyland (talk) 04:29, 17 April 2024 (UTC)[reply]

It depends on a lot of factors, but probably the biggest one is just whether enzymatic function can happen well enough at those temperatures. Not only is temperature an important factor in any equilibria or reaction rates (see reaction rate, Arrhenius equation, equilibrium constant, Van 't Hoff equation and Van 't Hoff plots, etc.) and are enzymes often quite pH dependent, which itself changes as a result of temperature, but at different temperatures the physical structure of enzymes, i.e. how they are folded and other structural issues, can change. This will denature the enzymes, potentially permanently, and a denatured enzyme either has incredibly reduced function or total even loss of function. That said, there isn't some magic one temperature that is best for all enzymes in nature. Rather, as a result of evolution and natural selection, the enzymes of a particular organism will be at their optimal temperature and pH range (or close enough to it for organism survival) for the given conditions of that organism. If you try to put human lysozyme in a chicken or a cat, it likely will not function. However, chickens and cats have their own versions of lysozyme which do work at their operating temperatures. Put chicken or cat enzymes in us, and they might not thermally denature, but they might not be at an optimal temperature for enzymatic activity (or worse, the direction of the equilibrium could even shift, depending on the thermodynamics involved). The adaptations needed to adjust enzymatic optimal temperature ranges often (but not always) aren't very complicated, to the point that a few degrees Celsius adaptation might only require a single point mutation changing one codon/one amino acid. However, even that can become a problem when you have a lot of enzymes needing to adapt to a very quickly changing temperature condition. Thus the problem with coral bleaching, for example. Not having a lot of temperature regulation and being dependent on external temperature, if a temperature shock happens too rapidly for generational/evolutionary adaptation, you start seeing bleaching and eventually extinction events (we have extensive fossil records of other temperature shocks that wiped out the vast majority of marine corals). --OuroborosCobra (talk) 14:53, 18 April 2024 (UTC)[reply]

An intelligent bird might just as easily ask "How can some mammals have lifelong low core temperatures?"

Everything is relative, and birds have been around something like 160 million years longer than H. sapiens, so their 'normality' is more established than ours. {The poster formerly known as 87.81.230.195} 151.227.134.31 (talk) 16:08, 17 April 2024 (UTC)[reply]

Their biochemical and enzymatic activity is optimized enough to that temperature for function. Same as any other living thing. --OuroborosCobra (talk) 17:26, 17 April 2024 (UTC)[reply]

There's been some studies which indicate there may be two phases of liquid water with a mixture from 50°C-65°C which is a major barrier to life evolving to work at a higher temperature. NadVolum (talk) 20:30, 26 April 2024 (UTC)[reply]

April 17[edit]

Hi. The medical field has been using Modified-release dosage tablets/pills/capsules for decades.

Today, I heard about Nicotine pouch on the news. I have never came across this delivery method before, so it got me curious. Nicotine pouch slowly release Nicotine over time, in an analogous way as modified-release dosage tablets/pills/capsules slowly release medication over time.

1. Are there any medication that is delivered via the pouch method?

2. There are Nicotine pouch, Nicotine patch, Nicotine gum, and Nicotine Lozenges[1] that is kept in the mouth but must not be swallowed. There are probably many other nicotine delivery methods that I am not aware of. Are there any Modified-release dosage nicotine tablets/pills/capsules that you swallow?

3. To the best of my knowledge, it seems like almost every nicotine delivery method that goes in the mouth is kept in the mouth, and must not be swallowed. Is there a reason for this?

OptoFidelty (talk) 05:28, 17 April 2024 (UTC)[reply]

• It seems that nicotine causes nausea and vomiting when it hits the stomach. Also, the stomach acids destroy it, according to Quora. This article says that a time release pill for treating ulcerative colitis with nicotine gets a lot of nicotine where it's needed in the colon, but not so much in the bloodstream. The nicotine in the pouches and other delivery methods needs to travel across the mucous membranes, skin, or lungs to get people feeling good. Abductive (reasoning) 10:37, 17 April 2024 (UTC)[reply]

Thank you! OptoFidelty (talk) 18:53, 17 April 2024 (UTC)[reply]

Some medications (and foods) besides nicotine are being packaged in edible film pouches or capsules. [2] It's been studied for new methods of drug delivery [3] but I haven't personally seen anything other than self-medications taken with these kinds of pouches. Reconrabbit 01:42, 19 April 2024 (UTC)[reply]

April 20[edit]

One of my favorite webcomics, Saturday Morning Breakfast Cereal, once made a joke about Xia's five-body configuration (comic here). I went looking for what it was talking about and found our article on the Painlevé conjecture, to which I added a redirect-with-possibilities. As an aside, the article could use some TLC; the most glaring problem is that it introduces variables without saying what they represent.

Anyway I was trying to figure out where this infinite energy was supposed to be coming from. My best guess so far is that the five bodies are idealized as point masses, which means that the gravitational energy released as you let two of them approach one another grows without bound. This of course would make them black holes in our actual universe, so that energy wouldn't be available, but in the universe of the comic, I guess this wouldn't be a problem (I've never thought very deeply about what happens to general relativity as c approaches ∞, so I'm not sure about that). But in any case there's no new energy appearing that wasn't there before, so the comic's claim that "the universe collapses" seems wrong.

No, really, I actually do have a sense of humor. I just want to know if I've understood this correctly. Does anyone have a different understanding? --Trovatore (talk) 19:50, 20 April 2024 (UTC)[reply]

O/T That article rather overeggs the pudding. The various proofs are for the 2d case ie planar. Perhaps it is obvious that if it works in 2d it'll work in 3d. Greglocock (talk) 21:22, 22 April 2024 (UTC)[reply]

I'm not too sure what it means to "overegg the pudding" but I was not interpreting the configuration as planar; if that's correct then I've misunderstood the drawing. Can you point me to why you say that? --Trovatore (talk) 21:43, 22 April 2024 (UTC)[reply]

It means exaggerating the utility of . The repeated use of the word planar is what I was getting at.Greglocock (talk) 05:45, 23 April 2024 (UTC)[reply]

The last section of the AMS article by Saari and Xia has this: "While we now know that noncollision singularities exist, several mysteries remain. Any partial listing has to include whether n = 5 is the cut-off for this surprising behavior, or whether the four-body problem can propel particles to infinity in a finite time. Can, for instance, Anosov’s suggestion be carried out? Are there planar examples with small n values?" This implies IMO that Xia's construction is non-planar. I think the sketch of the construction also implies this: the orbits of the pair of point masses m₁ and m₂ are said to be parallel to the x-y plane and highly elliptical, while m₃ moves along the z-axis. The orbits of the pair m₄ and m₅ are also orthogonal to the z-axis, with their major axes shown at an angle to those of m₁ and m₂ in the accompanying figure.  --Lambiam 12:52, 23 April 2024 (UTC)[reply]

Energy borrowed from the potential energy shed by point masses approaching each other closely but not, in the finite time, "arbitrarily closely", can only be finite. To reach infinity their distance has to become less than any positive number, which means it is zero. Doesn't that qualify as a collision? What is worse, in Jinxin Xue's 4-body solution all four bodies are said to escape to infinity in a finite time. Do they scoot off in four different directions?  --Lambiam 13:18, 23 April 2024 (UTC)[reply]

I believe the idea is this: as you approach the time of the singularity, the separation between some pairs of masses approaches zero, but the positions of those masses diverge to infinity. If you consider a collision to be when two masses have identical, finite coordinates, then that never happens in this scenario. --Amble (talk) 22:59, 23 April 2024 (UTC)[reply]

How hard would it be to construct it from satelitees? Zarnivop (talk) 22:41, 25 April 2024 (UTC)[reply]

You could put satellites in the right pattern at some starting time, but they wouldn’t actually behave as predicted by Xia’s model. That’s because the model requires perfect point masses in a Newtonian universe affected only by one another’s gravitational pull. Real satellites have other forces acting on them, have negligible influence from each other’s gravity, and are not point masses. And of course, real satellites aren’t in a Newtonian universe. —Amble (talk) 02:25, 26 April 2024 (UTC)[reply]

April 23[edit]

While adding a brief historical context section to that lemma I noticed some former changes of another IP which I doubt to be correct. Please could somebody countercheck, since I have no access to the referenced Elsevier source documents from which the data has been obviously originally taken. Here the difflinks in question:

• Special:Diff/1218613828 Section or not a section?
• Special:Diff/1218613911 Greater or less than 100.000 Volts? Grounding or grounding substrate?
• Special:Diff/1218614055 Second half of a sentence was removed. Does that make sense?
• Special:Diff/1218614423 Negative or positive? Discharge or charge?
• Special:Diff/1218614559 100 million volts or only 100 volts?

I would tend to revert these unverified changes, they look illogicaly to me, but wanted to ask here first.

Many thanks! --92.117.130.94 (talk) 05:06, 23 April 2024 (UTC)[reply]

P.S.: Maybe there is a need to improve my wording or grammar in the historical section I have added, since I'm not an English language native speaker, sorry if I've used unusual or strange wording. --92.117.130.94 (talk) 05:12, 23 April 2024 (UTC)[reply]

Thanks for noticing. I've reverted these edits because they look like vandalism to me. HansVonStuttgart (talk) 08:13, 23 April 2024 (UTC)[reply]

April 26[edit]

Are there analytical expressions that describe how the radii of white dwarfs change with mean molecular weight? JoJo Eumerus mobile (main talk) 19:06, 26 April 2024 (UTC)[reply]

See White dwarf#Mass–radius relationship. The radius goes down fairly quickly as the mass increases. NadVolum (talk) 20:13, 26 April 2024 (UTC)[reply]

The radius depends on the mean molecular weight through the number of electrons per unit mass N. Ruslik_Zero 20:27, 26 April 2024 (UTC)[reply]