> The sensory fibers are the outside of the nerve(insulative portion of the cable) and the motor fibers are the inside(copper wire).

Can you cite a source to support this? I can't find one, and I did find a paper where they attempted to image the fibers (https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-021-02871-w). Their images seem to me to show them all mixed together.

I'm concerned that it would be irresponsible to answer your question because you might attempt some of these methods. A few days ago you were asking whether it was a good idea to dry your pantry by pouring sodium hydroxide into a corner. (Just to be clear, the answer is NO.)

These substances can be safely dried by people with appropriate equipment, knowledge, common sense, and oversight. You have demonstrated none of these. If you attempt to dry sodium hydroxide at home, by any method, you will create a damaging chemical accident. If you are interested in chemistry, and you enjoy having an intact home, two functional eyes, and a clean criminal record, please stop asking these questions on Reddit and go take a class at your local community college, or anywhere else that you can receive the education you need in a safe and supervised environment.

There was a ton of guessing involved. One of the key guesses, which turned out to be correct, was that all the metals were elements. But people also guessed that "earths" were elements -- we now know they're oxides of the true elements.

Lavoisier made an influential list of elements, and some of them were wrong. He listed lime, magnesia, alumina, baryte, and silica as "earth" elements. He also missed some, like sodium, even though derived substances like lye and salt were well-known.

Lavoisier also guessed, based on analogies with known elements, that there were some elements that had not yet been isolated, like fluorine and chlorine. Interestingly, his reasoning was wrong. He thought that acids were produced by a nonmetal reacting with oxygen. Therefore, the existence of "muriatic acid" meant that there must be some "muriatic" element which combined with oxygen to produce this acid. In reality, muriatic acid did contain an unknown element (chlorine), but oxygen wasn't involved -- it's just HCl.

Most of Lavoisier's mistakes were resolved fairly soon. Davy isolated calcium, barium, and magnesium, which was fairly convincing evidence that the other "earths" were really compounds of unknown metals. (He also made chlorine, sodium, and potassium.)

There are fully analog ways to get fractional power that don't require a voltage divider. For example, a variable transformer would work just fine in an electric stove. But a variable transformer is also much larger, more expensive, and less efficient than a cheap relay.

Yes, the kidney will retain bicarbonate, but unfortunately, under normal conditions the kidney already reabsorbs close to 100% of bicarbonate. So unfortunately this mechanism cannot be increased enough to fully compensate for respiratory acidosis.

The kidney has other methods to indirectly raise the pH, like excreting ammonium (which would otherwise be reacted with bicarbonate in the liver). Other acids can also be excreted. However, renal compensation for respiratory acidosis takes days. The lungs are much faster at removing acid from the body than the kidney is.

It doesn't directly eliminate H^+ from the body. As you said, there is net zero transport of H^+. Instead, a base (bicarbonate) is reabsorbed into the body.

You should not believe that every bicarbonate ion actually reacts with an H^+ ion -- there is a complex buffered equilibrium. But each reabsorbed bicarbonate shifts that equilibrium slightly toward the alkaline side, because it has the capacity to accept an H^+.

I think the answer is really "it depends."

Let's look at just your body, because you are one of the many parts of nature that recycles dead organisms. You reuse some of the amino acids you eat, but you also burn a lot of them for energy. Even if you eat 100 g of protein every day, you don't put on 100 g of new muscle every day. So every day, you are burning at least some protein for energy -- turning it into basics like carbon dioxide and water and something nitrogenous. (In humans, the nitrogenous product is mostly urea.)

Also, most proteins in your body don't stick around forever. They are broken down and rebuilt. But the time frame can vary a lot. Collagen, for example, can have a very long half-life: over 100 years in cartilage and 15 years in skin according to [1]. At the other end of the spectrum, some enzymes have a half-life of hours [2]. So some of the amino acids currently in your proteins will be burned today and replaced by dietary protein. But because of the variability, it's very hard to say how long the average amino acid in your body stays an amino acid.

Similar things can be said for basically any biomolecule. For example, a nucleotide can "live" for a long time if it happens to be part of the DNA of a neuron or other long-lived cell, and for a much shorter time if it's in in the DNA of an erythroblast (red blood cell precursor) whose nucleus will soon be ejected and metabolized.

[1] Verzijl et al., "Effect of Collagen Turnover on the Accumulation of Advanced Glycation End Products," https://www.sciencedirect.com/science/article/pii/S0021925819558288

[2] Mathieson et al., "Systematic analysis of protein turnover in primary cells," https://www.nature.com/articles/s41467-018-03106-1

The tetanus part probably lasts for much longer than 10 years in most people (cases of tetanus in people who received their primary series are vanishingly rare, and some countries don't even give boosters) [1]. But tetanus is kind of like rabies... you'd be crazy to mess around. Even a nonlethal case of tetanus is devastating. Thus, the recommendations tend to be quite conservative, and you should be too.

The aP part (acellular pertussis), on the other hand, actually doesn't last very long. The acellular vaccine unfortunately is just not as effective as the now-discontinued whole-cell vaccine. So even if you think the tetanus version isn't strictly necessary, get your booster for the pertussis portion....

[1] Hammarlund et al, "Durability of Vaccine-Induced Immunity Against Tetanus and Diphtheria Toxins: A Cross-sectional Analysis," Clinical Infectious Diseases 2016.

Yes, they are actually equal... well, sometimes.

Dominance is irrelevant here. "Dominant" doesn't mean "more likely to be inherited." A dominant allele is one that gives you its distinctive phenotype when you inherit just one copy. A recessive allele requires you to inherit two copies before you have that phenotype. That's all. [1] The Punnet square works the same whether the alleles are dominant, recessive, incompletely dominant, or whatever.

Each axis of the Punnet square represents the two homologous chromosomes of one parent's diploid cells. When that cell undergoes meiosis, the homologous chromosomes are separated. One goes into one child cell, and the other goes into another. So each of those chromosomes is present in exactly 50% of the gametes. The same is true of the chromosomes in the other parent. So if you're heterozygous at an locus that codes for something like purple vs white flowers or something like that, half your gametes will have each allele. And if your partner is too, half their gametes will have each gene.

For the purple/white flower gene, that also means exactly 25% of your offspring will have each combination. One gamete at random from each partner. It doesn't matter whether the purple flower gene is dominant or incompletely dominant or whatever.

If the difference between the alleles is something more serious -- for example, not purple vs white flowers, but whether or not you successfully gastrulate -- the allele frequencies in the offspring are going to diverge from 50/50. This is evolution through natural selection. If the "can't gastrulate" allele is recessive, you won't see 25% of descendants in each quarter of the Punnet square. In fact, 0% of the offspring will be homozygous for the "can't gastrulate" allele, because they all died as embryos. However, if we observed the embryos at the moment of fertilization, there would still be 25% of each.

Sometimes natural selection happens before fertilization too. If an allele makes your gametes not work so well, those gametes will be less likely to even make it to the point of generating an embryo. For genes like this, the 50/50 model of the Punnet square kind of stops working. When you think about it, this kind of allele might actually be pretty common. Gametes don't just do gamete-specific stuff like making flagellae. They also need to do normal things like transporting glucose into the cell, and if they are worse at any of these normal things, they're probably less likely to succeed at being gametes. On the other hand, they probably don't even express the gene for flower pigments, so that one is probably truly 50/50.

[1] In reality, a lot of alleles aren't really 100% dominant or recessive. If you are heterozygous, you may get a phenotype that's somewhere in between the homozygous phenotypes. Sometimes it's exactly halfway between, but it is often very close to one side or the other, and those genes are considered dominant and recessive, even if they aren't truly 100% dominant or recessive. But none of this is relevant to the frequencies in the Punnet square.

Just to put this in perspective, you are also 0.0006% lighter if you climb 20 meters further from the center of the earth.

Just to address the other answer, the epiglottis prevents food from entering your trachea. It doesn't help direct air between your mouth and nose. It is not anywhere near the right location to do that.

The palate and tongue can make a seal that blocks off the mouth, forcing all air to move through your nose (even when your mouth is open).

The soft palate can't fully block off the nasopharynx in normal people, so there's always at least some air coming through the nose, but with a wide-open mouth and lifted soft palate, chances are more air is going to move through the mouth.

In [1], when subjects were not exercising, some breathed only through their noses, while others breathed partly through their mouths; however, even in the mouth breathers, 70% of the air came through their noses. When the subjects were exercising hard, everyone used their mouth. The proportion of air passing through the mouth reached 70% in habitual "mouth breathers" but only 60% in habitual nose breathers. This is probably because people who habitually breathe through their mouths have higher nasal resistance.

[1] Niinimaa et al., "Oronasal distribution of respiratory airflow" (1981), https://pubmed.ncbi.nlm.nih.gov/7244427/

If you think about it, the food we eat mostly ranges from glucose (CH*2O)n* to fatty acids (empirical formula CH*3(CH2)nCOOH. None of this has enough oxygen to get converted to CO2* without additional oxygen from somewhere.

It's true that it does not come directly from atmospheric oxygen, but indirectly it does. The atoms basically all get mixed around. For example, in glucose metabolism, oxygen reacts with reduced cytochrome c and H^+ to become water. Water hydrolyzes various phosphorylated substances to produce ADP and phosphate. The water and phosphate will donate this oxygen back in subsequent steps.

In glycolysis, two of the sugar's 6 oxygen atoms are eventually replaced by phosphate along the route to forming pyruvate. During decarboxylation of pyruvate, one of the lost oxygens is original to the sugar, while the other is the newly added one. So for the CO*2* molecule formed by pyruvate decarboxylation, it's half-and-half. One of the oxygens came from phosphate. The other came from the sugar.

In the citric acid cycle, another two CO*2* are produced by successive decarboxylations of isocitrate. Of course, it's a cycle, so more oxygen atoms have to be added back in. Of these, two come from water, one from phosphate, and one from pyruvate (originally glucose). So again, some of the oxygen in the CO*2* produced in the citric acid cycle comes originally from the sugar, but the majority comes from phosphate and water.

Well, it presumably makes sense to spend $4000 to save $2000/year, as long as you keep the new car for more than two years. Keep it for even 3 years and it's a better rate of return than you'll get anywhere else.

Now, I don't know if doing a trade with CarMax is the optimal way to do this deal. Maybe there's a better way. But it does seem to make sense.

Your original post has a list of 7 events (A1 through A7) in increasing order of probability. The difference between P(A1) and P(A7) is many orders of magnitude, with huge jumps from each statement to the next, and there is seemingly no grounds for preferring to study one of these statements to any other. Even if you try to use the principle of including all information, it's not clear where to stop. You'll just worry that you needed to choose A0: Juliet won twice, at 9PM, and the weather was cloudy both times. Compared to P(A1), P(A0) is another order of magnitude lower.

But if you realize that you actually care about, not P(A1), ..., P(A7), but P(R|A1), ..., P(R|A7), then it's easy to see that adding cloudiness does not actually change the result. In a Bayesian formulation of the problem, only relevant information matters. P(R|A0) = P(R|A1). You can ignore the weather.

The point of the last statement in the previous post is that, if you know no particular distinguishing information about Juliet, you can calculate P(R|A) or P(R|J) and it doesn't matter, because you still get the same answer. So as long as you use Bayesian reasoning, you are basically free to pay attention to the specific identity of the person, or ignore it, without affecting your conclusion.

Let's say you let J be the event that Juliet wins two state lotteries back to back, and let A be the probability that anyone wins two state lotteries back to back. Let R be the event that the lottery is rigged. What you really want to know is the posterior probability that the lottery is rigged, and this could be P(R|J) or P(R|A).

I'm interpreting your question as asking: how should I choose whether to care about P(R|J) or P(R|A)?

Fortunately, if we know nothing about Juliet, it doesn't really matter. See, you can calculate P(R|J) = P(J|R)P(R)/P(J), and you can also calculate P(R|A) = P(A|R)P(R)/P(A). I claim these calculations will produce very similar values when we know nothing about Juliet. P(R) is of course common to both. Canceling it from both expressions leaves P(J|R)/P(J) in the first expression and P(A|R)/P(A) in the second.

In the second expression, both the numerator and denominator are larger. There are at least a thousand people who play the New Jersey lottery^([citation needed]), so we expect P(A) > 1000P(J). But similarly, if the lottery is rigged, it could be rigged in favor of any of those one thousand people, so we also expect P(A|R) > 1000P(J|R). If we genuinely do not think any of those people is more likely to be favored by the rigging than any other, then the ratios will be exactly the same and our calculated probabilities will be the same too. In this case it doesn't matter whether we care about P(R|J) or P(R|A).

Remember, this only works if Juliet is an arbitrary person. If we do know that Juliet is the daughter of a crooked New Jersey politician, then maybe we think that if the lottery is rigged, it's quite likely to be rigged in her favor. In that case, we might say P(A|R) = 10P(J|R), while still believing that the lottery is probably not rigged and P(A) = 1000P(J). Then P(R|J) is going to be 100 times bigger than P(R|A). In this case it would be wrong to use P(R|A), because it's throwing away important information (Juliet's crooked connections).

In summary, in both cases we should really condition on the more specific event (i.e. we care about P(R|J)), because that takes into account all the available information. But luckily for our sanity, when we have no special information about Juliet, P(R|J) = P(R|A). So even though you want to condition on all the available information, it's fine to ignore information that means nothing to you.