Very Interesting!

especially if those books don't have metal inserts or anything like that?

Because it DOES have metal inserts. They are called RFID chips, and they are very small and very cheap. You can even buy them. I suggest google image: "rfid chips label and tags"

I work in a fairly poor urban library and we do use RFID chips, which are great for self checkin and checkout. They're on everything, including wee DVDs.

Every few years we have a run on toilet paper (in one series of instances, a lady would bring a bunch of kids in a couple times a week and they would break the paper holders and conceal massive amounts in the kids' backpacks). A bunch of RFID tags inside the TP rolls, and you've found the culprits.

Moral: Don't steal from libraries. We're here to help you borrow things for free.

The most well-known anti-theft device for books is a tape of magnetic metal strip. The tapes are applied between the spine and the binding of a book (for hard covers) or deep inside in between some pages (for paperbacks). It's called tattle-tape.

Do you know how if you hold a tuning fork near your mouth and sing the right note, the fork will sing back? The books contain very thin "tuning forks" that look like stickers. The scanner you walk through emits a tone that causes any near by "tuning forks" to ring at that same frequency. The scanner then listens for the resonating forks and sounds an alarm if it hears any. You can't actually hear the frequency though because it is done with radio frequencies.

Edit: It occurred to me that I didn't actually answer ops question. Basically when you check in or out the book it runs over a large magnet what wacks the tuning fork into and out of tune.

A lot of books have the metal inserts in their spine or in their cover where you can not see them. But it is not unlikely that the scanners are unable to pick up on every book, just the most valuable ones which have the metal inserts. The way these work is tha the metal inserts are in a perfect length to create a magnetic resonance that precisely matches that of the scanner. So when you walk through the scanner the magenetic field makes the metal inserts resonate which can be detected by the scanner. However during the checkout they use a magnet to change the magnetic characteristics of the metal insert and therefore its resonance frequency. This prevents it from triggering the scanners. This is also a reversable action so they can reset the books when you return them.

Pilot here- it's 99% theatrics to make it more dramatic in TV and movies.

The 1% of the time when it's real would occur in only a couple situations.

In a fly-by-wire aircraft, the pilot's inputs are fed into a computer that in turn actuates the control surfaces. A malfunction in the computer that causes a sudden, extreme control input, such as what happened in Flight 302 would be a situation likely to have the pilots fighting the controls to override the input (though there are established procedures that go beyond just fighting the control input)

In a manual flight control aircraft, where movements of the flight controls move pulleys and wires attached to the control surfaces, a failure such as a jammed pulley or sudden disconnection could leave a control surface-and the plane- in a dangerous configuration in which the pilots might be attempting extreme control inputs to stabilize the aircraft.

But overall, dramatically fighting the controls as in movies is a mostly futile endeavor. There are procedures and redundancies in place in most aircraft that make it unnecessary.

As others have said, that's largely theatrics in movies and TV.

There are essentially three systems in use:

• Fly-by-wire is what you will predominantly see in modern airliners and military aircraft. Here, your stick isn't actually physically linked to any control surface - instead, your inputs send signals to a computer which then positions flight control surfaces to do what you are asking the computer to do. The computers are, in relaxed stability aircraft (like fighter jets), actually continuously sending signals to the flight controls to keep the jet flying stable. In some aircraft, if you turn off the flight control computers entirely, your jet is no longer able to maintain controlled flight.

In this case, the fighting control stick does absolutely nothing. In fact, you won't even feel the actual feedback from flight control surfaces on aircraft because the stick isn't directly linked to them.

• Hydromechanical. This is used in older fighter jets and in airliners/aircraft with big control surfaces. Basically, when flying at faster speeds (which creates larger pressure/air loads on control surfaces), human power isn't enough so the control stick is mechanically linked to hydraulic systems that move the control surfaces for you. These hydraulic circuits operate in the thousands of psi. For instance, if you pull the stick back, you are mechanically telling the servos and actuators to move the stabilator (or elevators) to pitch the aircraft up.

In this case, if you did have something go wrong, fighting the stick doesn't do much either. Most likely, if something went wrong, it's because your hydraulic line or mechanical linkage broke, or you lost a control surface. In which case, fighting the controls won't do you anything.

• Direct linkage. This is what you commonly see in older aircraft/lighter aircraft/general aviation like in your Cessna. Here your control surfaces are directly linked to your control stick/rudder via wires and pulleys. You will directly feel the loads on the control surfaces.

Here is where you could, like in the movies, perhaps try to fight for control via physically fighting the stick more. A jammed linkage or connection might require more force to fight through. But even then, you risk breaking something even worse (sudden snapping of control surfaces can overwhelm mechanical limits) OR getting into a PIO (pilot induced oscillation).

MORE likely to happen is if you have a failure in a control surface (e.g. an aileron fails), you have to put in some input like rudder or opposite aileron to keep the plane flying straight and level. In that case, you are "fighting the controls" by keeping some force on the stick to maintain the flight attitude you want. But you aren't "fighting the stick" like in the movies - instead, you're precisely and finely putting your control inputs in (or trimming the aircraft) to offset what was lost.

Helicopter pilot, answer is you don't unless the hydraulic system has failed. This is less likely the larger the helicopter as they have multiple independent hydraulic systems so one failing has no effect at all. Smaller helicopters like Jetrangers or Astars are harder to control with a hydraulic failure but not even that bad, we train to land with the hydraulics off by flying real aircraft with the hydraulics turned off, it isn't considered dangerous to do so. For a large helicopter if you somehow had all hydraulics fail at the same time depending on the type it is a major emergency and possibly unrecoverable.

They don't, that's just in the movies. In fact fighting the controls can make things worse. A perfect example is American Airlines Flight 587, the aircraft flew into the turbulence behind another aircraft, and the First Officer, who was the pilot flying, panicked and fought the rudder so hard that he ripped the tail off causing the aircraft to crash killing everyone.

Another pilot here. All the controls in my plane are directly connected to the yoke and pedals (manual). When airflow is low, especially during slow flight such as during landings, controls require exaggerated expression. They don't have much lift being generated to cause a change. Alternatively, very strong winds in lighter aircraft can definitely cause you to fight. They can quickly push you and change your pitch, yaw, and roll (these are the axis of motion). In this case you have to counter the effects of the wind.

Most of this is experienced extensively by all pilots in training. But it can take real physical effort (without much return from the controls). Usually however, you fly with "two fingers". A light touch will do it 9 times out of 10 if you're trimmed in (tuned controls to stable). Remember, flight is across long distances and you generally navigate on 10° increments (eg 010° - 360°) or smaller so planes must fly on small movements and corrections not grant turns like you see on movies.

The only times I've ever done movement like that when not training and with passengers was during some landings where the wind goes dead on me or once with an engine out on takeoff with about 400 feet below me to return to runway.

Where can I start my lucid dreaming path (book recommendation?) and what are the proven benefits (and negative effects) of lucid dreaming?

What happens to our brain when we are lucid dreaming? Is it still able to “clear waste”?

I’ve lucid dreams (and vivid dreams) since I was a child (I’m now in my 40s). I remember 90% of my dreams and I’m always aware that I am dreaming.

But: many times with lucid dreams I wake up tired. Like I spent the whole night just awake. Any findings related to that?

What is consciousness in your opinion?

I have aphantasia. Dreams are pretty non-existent for me, but when I do dream it's not really visual in nature - more like ideas/concepts, conversations - that sort of thing. Do you think it is possible to lucid dream without internal visualization?

Individual virions contained 24 ± 9 S trimers (Extended Data Fig. 1b). This is fewer than previous estimates that assumed a uniform distribution of S21, because S was not uniformly distributed over the virus surface. A small sub-population of virions contained only few S trimers whereas larger virions contained higher numbers of S trimers. Ke et al Nature 2020 https://www.nature.com/articles/s41586-020-2665-2

Coronavirus are what's referred to as Positive Strand RNA viruses. What this means is that the virus genetic material comes ready to be translated into protein. But that would mean that their single long "genomic" script would only make 1 protein. They get around this by coding for their own RNA polymerases that read at multiple subgenomic regions. These polymerase are also not made at the same time, the virus translates proteases that cleave the long strands of protein to smaller functional proteins.

At the very end of all of this, are the structural capsid proteins that include the spike protein. You can imagine that different effective rates of all the proteases and polymerases I discussed (there's also the speed in which trans cleavage occurs) that you're going to get some variability in the rate that the spike protein will be made according to the number of capsid proteins made (which is always the same). Especially since at the final step, the viral genome is just stuffed into the available capsid and there's no real "counting" system established for how many spike proteins are on it.

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The top of the tree is in charge. It grows like crazy to get more sun and make more side branches. More sun and more leaves mean more sugar and trees like sugar too.

Eventually the side branches can't hear that bossy top - they grow a little more and soon they're telling the buds behind them to grow more side branches while they chase the sun and make more sugar.

Douglas Fir and Sequoia and Red Alder branches have really good hearing and only rarely subordinate.

Lilacs and Hornbeam and Willow never listen.

Trees that are topped go crazy - there's nothing to listen to.

It's because trees want to take a shape that works for them.

Basically trees have five main things in mind.

Keep anchored (which is the job of the roots), suck up water and fertilizer (also the roots), don't fall over (the roots plus the trunk), reach more sunlight (the branches and the leaves) and suck up sun for energy (the leaves).

There's a lot of different ways that a tree can do all five, but it really can't do the fifth one very well unless it spreads out sideways a little (yes, there are exceptions like palm trees). The reason for this is the leaves get in each others way, blocking the sun.

So as it grows, it splits, and this lets more leaves be in more sun because the tree starts getting more sideways as it gets taller. Now the tree COULD just keep trying to keep all its leaves and grow taller and taller without branching... but this starts making "don't fall over" a lot tougher at some point.

So the tree branches to get more light once it gets to a certain size, and keeps branching after that to collect even more.

At least for some trees, there are special cells (apical meristem) at the end of a stem. These cells produce a chemical (auxin) that stops other stems from branching. As the stem grows long, there is less of that chemical so other stems start to branch off.

The first stem a tree has is the trunk. So after the tree is tall enough, a new stem branches off and the tree starts to get wider at the top. This happens again and again over time.

As it grows taller, the older stems get bigger around to help support the weight. This is able to happen because the tree keeps its food and water movement cells just under the bark. Over time, these cells are made more rigid with other chemicals and new food and water movement cells grow on top of those.

This is why we see rings when we cut into a tree also. This process usually happens on a yearly cycle, so we can often count those rings to know how old the tree is.

This is important to your original question because those special chemicals from the ends of stems are pushed around by the food and water cells. That affects how much of the chemical is in any part of the tree and isn’t a perfect process.

Since this is ELI5, I’ve definitely oversimplified. Someone linked a post in r/askscience that has the more technical names.

I don't remember much of the technical lingo from my Aboriculture class (Ecology, Evolution, Natural Resources Degree), but the simple answer is that usually one tree stem is dominant and this becomes what you know as the trunk. What will sometimes happen is a second stem will compete for dominance and both will grow around the same rate. This causes the split that you see. Sometimes those split trunks will even fuse together and form one larger trunk, which is better for the tree.

Edit: still have my text and it confirms that whether or not a tree will actually split is due to genetics, but the reasoning above is accurate.

Edit2: I'm not suggesting 2 trunks are better than one. I was just making a point that it's better for the tree if they fuse together, which is not likely. One trunk is always better.

Arboriculture 4th edition -Integrated Management of Landscape Trees, Shrubs, and Vines by Richard Harris, James Clark, and Nelda Matheny.

Heres another interesting tidbit, trees can be made to split so you can harvest straight staves from them with a practice called pollarding: https://en.m.wikipedia.org/wiki/Pollarding

Common practice in the middle ages I believe.

Headphones off, they're listening to current music. Headphones on, listening to what to play next. One earphone up, matching beat and tempo/speed of both songs to mix well.

Once upon a time I was a (very) small time aspiring DJ

Djs need to hear both what you hear, and the music they are preparing on you headphones. They can do this electronically, but many quickly put down an earcup for convenience.

Everyone answered your question already but they used to sell only one side. https://i.pinimg.com/originals/90/84/96/90849653e9d6163bb8a8fd6a090d6997.jpg

It is kind of a pain to put the headphones on and off and then have to adjust one side of the headphones, so they came up with these one speaker hand held headphones. The people that I saw use these were guys that had residencies at clubs, so they had all the sound dialed in, and they would play for 3 or 4 hours a night.

When I was a dj, it was very hard to hear your headphones when playing on a loud system (club system). So I would wear both sides on my ears and maybe just take one side off just a tad so i can still hear the club speakers.

but to reiterate what everyone is saying, you are basically listening to two songs at once.

So in order to prepare the next song, the DJ need to set the transition. That’s what he is doing most of the time, listening to the next version to the mix in advance in order to launch it at the right time.

To make sure the beat of the next song matches the beat of the currently playing song. One ear to hear what is currently playing and the other to hear the one that will be played next

There is, and it's called the ICRS (International Celestial Reference System). It is an idealized set of coordinates, the current realization of which is called the ICRF (International Celestial Reference Frame) version 3.

Astronomical reference systems are based on the celestial sphere, which is the backdrop of very remote galaxies and other radio sources that are for all practical purposes so distant as to be effectively motionless. If you can fix a set of three orthogonal axes with respect to this sphere, and define its center, then you're done.

The center of the ICRS is the barycenter (center of mass) of the solar system. This is quite close to, but not exactly at, the center of the Sun.

The two biggest features on the celestial sphere for Earth astronomers are the ecliptic and the equator. The ecliptic is the circle on the celestial sphere that the Sun traces out over one year. It is the projection of the orbit of the Earth onto the 'universe'. Likewise the equator is the projection of the plane of rotation of the Earth. If you label their intersection (the vernal equinox, which is where the Sun is around March 20th) as the positive x-axis, and define that positive z is in the direction of angular momentum of Earth, you've basically captured the idea. This is called equatorial coordinates.

Now this is tied to the rotation of the Earth, which is not as stable as first thought, which means this coordinate system moves. That's not good. The ICRS directions we use today are more or less 'frozen in time' on January 1, 2000, with a slight offset to account for the fact that we have better measurements since then.

The ICRF itself is defined as a list of coordinates of some very distant radio sources which can be pinpointed to very high accuracy:

https://hpiers.obspm.fr/icrs-pc/newwww/icrf/icrf3sx.txt

Other reading:

https://en.wikipedia.org/wiki/International_Celestial_Reference_System
https://en.wikipedia.org/wiki/International_Celestial_Reference_Frame
https://en.wikipedia.org/wiki/Equatorial_coordinate_system

Actual astronomers feel free to arrest me on inaccuracies.

There is no unambiguous "this place but 6 months ago". Such a description would need an unambiguous definition of "at rest" (staying at the same place), which does not exist. Something that's at rest for one observer will move for another observer and vice versa. Both views are equally valid.

All the coordinate systems we can introduce are arbitrary. The ICRS discussed by /u/TheBB uses the barycenter of the Solar System as reference. In that case Earth is ~300 million km away from the place where it was 6 months ago (twice the Earth/Sun distance). Similarly, you could use the barycenter of our galaxy as reference. Then Earth would be ~3 billion km away from where it was 6 months ago (largely from the Sun's orbit in the galaxy). You could also use the barycenter of the Andromeda galaxy, or any other reference you like, and you'll get a different answer every time.

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Ties into my thoughts a while ago... Astral Navigation sounds like it is very much impossible. Fixed reference points on earth are the locations of objects in the past. Move toward those objects, and they will change. At further lengths away from Earth, the locations of "known" objects are going to change significantly and/or they will be gone.

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They call this condition "honeybound"

Queens need open cells to lay eggs... If a colony becomes too cramped in their hive they will create a new set of queens and all the oldest bees and the old queen fly away to start a new hive in some other new space.. the young bees remain behind taking care of the new queens and new baby bees... the new queens have fatal duels until only one remains... typically if the first queen to emerge is healthy she will be allowed to go kill the other queens before they escape their cocoons... if the best queen is slow to emerge workers will protect that area from a lesser but quicker to emerge queen who would certainly eliminate that better competition given the opportunity.

If the space is extremely cramped or the colony exceptionally populous, they may also send a couple more swarms with newly emerged queens rather than having them duel down to one...

Ideally the best new queen takes the original colony... the old queen starts up a new hive elsewhere... if they're especially fortunate 2-3 minor swarms with new queens also begin anew.

Those minor swarms do not have great odds of survival but sometimes nature finds a way.

Update: thanks so much for all the gifts and goofy comments you all made my day = )

I've only been a bee keeper for a single season, but I take that responsibility seriously so I've tried my best to learn as much as I can so I can be a proper steward of my lil beebies.

I wouldn't call myself an expert by any means but I tell myself to learn like I'll live forever and serve like there's no tomorrow. I try to spend at least a little chunk of time learning more about bees everyday! They're fascinating and I'm a biologist so it's really a joy to learn all about them!

I'd like to encourage anyone and everyone who isn't allergic to work with bees and learn about them and help local bee keeper or become one yourself!

They're marvelous creatures and truly altruistic... working with them has been extremely rewarding and fulfilling... the hardest part is waiting for winter to pass.

As for how the bees select their favored queen? I guess that's one of their secrets, I only know about it because I've seen the way some workers guard their favorite unopened queen cell. I could scratch up a few paragraphs of ideas about factors that go into it but I'm already rambling hahaha... likely there is a lot to it.

Thanks again guys support local bee keepers and get your hands in the mix, most bee keepers are old timers and the industry needs more youthful energy and innovation!

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When there is too much honey in a hive they use it to keep themselves warm over the winter. They use the sugar in honey to sustain warmth so they don’t die. They eat the honey and vibrate around to create warmth. Bees live in a ball inside a hive. They stay at the bottom of the hive in the beginning and throughout the winter they move up towards the food source. Bees honey is mostly found at the top of the hive. If they have any left they use it to feed the bees and keep them alive for the next year. If they get too crowded for their hive, they swarm and take the old queen with them. The remaining bees can feed jelly to a newly laid egg and turn it into a queen. Usually a bee keeper knows when to split a hive.

Side note: if you do not leave enough honey your bees will die over the winter.

Other side note: I’m a hobby bee keeper in Maine, the winters are brutal. I love beekeeping, so if you have any other questions I’d be happy to help :)

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Motion blur occurs when the camera takes too long to generate the image. By the time the last bit of information is taken, the image has changed noticeably. So if all the information is taken in a very short moment, that difference is very small and the image looks sharp. However since the camera has less time to collect the light for the picture, shorter exposure times need a brighter scene. So the flash needs to be stronger or the scene just needs to be very well illuminated.

To further the other comments - if the location where they choose to take the photo is lit primarily by the flash (and I've not seen a roller coaster photo where that is not the case) then the duration of the flash effectively becomes the shutter speed (because the image is lit by the flash - and the camera can only capture an image while the flash is "on").

Flashes can have extremely short durations (1/1000 down to 1/20000 of a second) this means that they are really good at stopping motion.

Three things:

1. They use fast shutter speeds. That means that the shutter is only open for a very short period of time to gather data. And during that short period of time, you don't move much. Imagine you took a video at 3200 frames per second, then advanced it frame by frame. The movement would be almost imperceptible. That is how much you move while the shutter is open. They probably shoot at 1/3200th or even 1/6400th. The down side to having the shutter open for such a short period is that there is not much light that gets through in such a short period of time, so...

2. They use bright, fast flashes. That flash will pulse with each shutter click and it will be timed to illuminate the riders for the same length of time. So the riders are getting hit with a very bright light for only 1/3200th of a second and anything that happens outside of that window is too dark to really process.

3. They use angles to their advantage. Look out the side window of your car on the highway and things will be zooming by and you can't really focus on them. But look out the windshield and you can easily focus on approaching items.

Cameras have a depth of focus. These particular cameras are set to focus on a point in space that is let's say...3 feet deep. So as the riders are approaching the camera from the background toward the foreground, they will remain in focus for 3 feet as they pass through the camera's view. In 1/3200th of a second, they will probably move less than a quarter of an inch. So there is plenty of time to capture them in focus.

But if that camera were placed perpendicular to the coaster train and shooting from the side, the riders would zoom through the view much faster. It's the difference of trying to catch a baseball thrown toward your face and trying to catch a baseball thrown past your face from the side. It's much easier to see it coming straight on.

They can use a fast shutter speed because they have the flash lights. If the lights didnt flash when you went past there wouldn't be enough light hitting the lense in the time you were there, so the image would be dark. If the shutter speed is lower you get motion blur.

To add to the above, in broad daylight it is no problem at all to have a shutter speed of 1/4000 or even 1/8000 of a second.

Everyone undergoes ~ 20ish during gestation. And throughout your life individual cells undergo mutations that may of may not be passed down to other cells. Apoptosis prevents most from being passed down to other cells. By the end of your life it is possible to sequence a cell from your left hand and a cell from your right hand and get very very close but ever so slightly different sequences.

Ok.

This is really both a population biology, and a systems biology question, and it has to be broken apart as such. Here is a rough order estimate that will get you most of the way to whatever it is you need. Flame me if I am off by 50%, I dont care, but this is experience talking. Much of this data comes from sequencing, life science degrees, systems biology, bioinformatics, and most importantly Personal genomics and several discussion with the director of George Mason Systems Biology.

Back of envelope:

3BB. Human beings have around 3 billion base pairs

25k. This is encoding about 25000-30,000 "Genes"

This is segmented onto 23 pairs of chromosomes # 1-22 and X/Y

750MM. A quarter of that is coding and regulatory (750 MM bp), the rest non-coding.

10k. Now up to half (10000) of those coded genes are completely necessary, untouchable, "unmutated", conserved to a very high degree, and the fetus will stop development if they are changed in any way, so then those implantations fail out and mom will miscarry (up to 20% of the time). This is no ones fault. If you, as a budding little promising zygote, cant put a phosphate on a glucose molecule with hexokinase, you will not make it in this world. You absorbed nutrient of your placenta until you got to 128 cells, then it was too far a journey for diffucion. Same situation is for neurotransmitters, receptor proteins, cell cycle kinases, etc. There are many of those that you just can't change, and survive development. Some result in putting off the death drama, like lysosomal storage disorders, where a lack of the ability to take a sugar molecule of a brain protein leads to that now useless thing being shunted into a neuronal storage granule, until arund 2-3 years, when the child perishes. Be compassionate. All of us know these people.

1. Now there are changes in the other half of the genome with varying effect. For the remainder, we are talking about involvement of 7500 "rare" heritable genomic disorders. Gp investigate NORD for more info. Blindness, deafness, ALS, charcot marie tooth syndrome, Alpha-1 Antitrypsin disorder. Many of them. Mess with those and you have a disorder, if not a disease. Glass bones, inability to taste cilantro, we are legion.

Now let's call mutations "SNPs", or single nucleotide polymorphisms; changes. Half of the rare diseases are SNP related, half are multiple sites involved. We dont know a lot of those.

1. Last, people are actually mosaic. A person has at any moment 5-25 genomes in them, from localized cellular mutation. The changes are slight, but hey, one of them goes awry like cyclin dependent kinase 1, and you have a tumor since you cant control cell division in that tissue anymore. We hope that your killer T cells keep on cleaning up and seeing them. Then again, some SNPs are escape mutants without the receptors that TNK cells need.

So. What are the population numbers you ask?

1. Average people carry about 3-10000 SNPs in their 3 B bp genome. This is still only a vanishing part of who we are as a genome, 0.013 parts per thousand changed. We are way over 99% alike one another, changes and all. of those 5000 changes, over half are silent, non-deleterious changes. I have over 5k of those. We dont worry about them. They dont do anything. Look in your personal sequence file, find the (=). They are equivalent, silent, immaterial.

2. Then about 2-4000 changes are "likely pathogenic", where the SNP change results in a change in the protein of the gene, a charge change in it, a folding problem, a premature read stop. However, modern medicine is only up to knowing what a fraction of the genes do, much less correlating the changes to a diseases causally or with Pearson's R or some such. Currently about 25% of genetic diseases are mapped to a polymorphism.

3. Now at the last, if you are talking about "mutations", that is, SNPs, probably pathogenic, non-benign, and mapped to a disease or metabolic pathway, then the answer for a regular person is about a HUNDRED. I have about 45 of these. This is from sequenced human beings at INOVA, northern Virginia where they are getting the exome of every baby, rather than doing heel sticks for PKU, Down's trisomy, etc. Everyone has them, no one is perfectly functional at the genomic level. There are 25k bell curves of enzyme function in pop bio to eventually look at. We are the sum of all of it.

4. Now half of those changes are in only one copy, or yield to us a "carrier" status. You have one bad hit, the other is fine. You are "heterozygous". Bless the sexual reproduction, we have multiple copies of almost everything! These disorders just do not show up. The "incidence" of the change can be up to 5-10 % of the population. Rare diseases have under 2% incidence? However, if 48% of the populace carries a SNP, is that a variant? Thoughts. I carry SNPs that produce pathogenesis for 45 genes. Better than average but who wants 45 damages? Luckily more than half of these are recessive.

5. I have only informatically battered down about 22 of SNPs that cause some concern. Inosine metabolism, glutamate turnover, etc. You can lose yourself in Pubmed on this stuff. Thankfully, most of these changes result in enzyme activity being dropped by only 5-30%. Functionally, they have no perceptible effect, physiologically, that a practicing MD would call "disease". Will you be an olympic athlete? Sorry, VO2 max is limited to 78% because your lung neutrophil elastase is changed and unregulated by serpins, and now your alveoli have less surface area. Go take a spiromoter reading and get back on your bike. Will you be Einstein? No, of the 10k genes it takes to make a brain, you have 4 changes that impact catecholamine synthesis. Sorry. You have a good spleen though, that only took 5200 genes to make and the organ is unhit.

Now you are down to the very last category, which I think is what you are actually asking. For those persons who carry a deleterious mutation, a dominant SNP, which then results in disease, who are they and how many? Now we are talking about 5-10% of humanity carrying some form disease. Of my 5k variations, 2 are in this category. One is metabolic for which a protein can be taken be needle, one is structural for which there is no cure. Both of them result in 40% activity for that pathway. There are others that result in 25% that I can augment with nutritional support, hacking myself.

I live for the day when personal genomics makes medicine personal, for when genetics is not eugenics, for when the natural variation is treatable if pathogenic, and left alone if not. We are all humanity, we are every color. Your ability to metabolize alcohol better than me does not make you better or worse. We can be grateful for the math that aspergers has brought us, the violin of Paganini who could not connect two lysine molecules correctly to make collagen, so his fingers were extra flexible. This is who we are, a group of adventurers. We can work on crispr genetic therapy to fix beta thalassemia, and clotting disorders, and many of the above where a SNP has caused loss of function. We can work on situations wehre a bad protein builds up and gives you cirrhosis, with antisense RNA technology.

Now let me extend the last point. You may ask yourself, of, if I have 75 SNPs to worry over, they make me different by a fraction of a percent, and those genes control stuff like depression, ambulation, height, whatever. Is there anyone like me? Add up the chance of having each SNP at each position, for all your copies. What is the chance someone else has this "signature"? My answer is, you would need 50X the current poulation of the planet, to find a single person who has that set of SNPs or mutations. Even your brother carries half the SNPs you do.

All of us are unique. That's the statistical fact.

Thanks. Best of luck.

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You have them in every cell in your body (different ones) and every cell division adds another 10 to 100 or so. (Wrong, read EDIT below!!)

So everyone has them, probably a couple thousand per cell and old people have more than young people.

Which is why having an old father puts you at higher risk of borth defect.

EDIT: GUYS, I GOT IT WRONG! It's 10-100 mutations per GENERATION! Each cells ends up with 10-100 mutations in a lifetime, not each cell division!!

We tend to separate inheritable mutations - called 'germline' mutations - from non-inheritable mutations - called 'somatic' mutations. The mutation rate varies greatly between tissues. A large part of this is down to different rates of cell division, but that's far from the only factor.

The germline mutation rate is well documented, since we can look at genetic differences between parent and child to calculate this. It's around 0.5x10^-9 per base pair per year. We have about 3 billion base pairs, so that works out to about 1.5 inheritable mutations a year.

The overall somatic mutation rate in humans is a bit debatable, since to accurately measure it you'd need a constant stream of DNA samples from the whole body, due to different tissues being under very different pressures and environments. However, the best estimate I've found is about 2 mutations per cell division for every 100 million basepairs. That's roughly 15 mutations with every division. This number is likely to be rather rough, but it's probably a good ballpark.

It's difficult to say how fast, on average, we make new cells over our whole body. You often hear the factoid that we replace our bodies every 7 years, but that's a number that seems to have been pulled out of thin air. Most of our body replaces itself in under a year (Source) . Fat, bones, and heart muscle can take closer to 10 years, and nerves, lens cells, and oocytes (egg cells) are rarely replaced. Let's go for a ballpark figure of around a year on average, though, for all the cells. This is almost certainly incorrect, but it's also likely in the right order of magnitude. Perhaps someone else will feel industrious enough to calculate a more accurate average based on the relative number of cells in each category.

We have about 30 trillion cells (3x10^13) in our bodies, replacing themselves roughly each year. This give us a ballpark of around 500 trillion mutations a year.

If you're wondering why we don't have cancer of the everything all the time, it's a combination of many of those mutations being 'null' mutations - ie they have no effect. Those that do have an effect overwelmingly tend to be harmful in that the cell just doesn't function and dies. Those very very few that have cancerous potential are, by and large, immediately destroyed - either by a cell's own security features causing it to self-destruct, or by our immune system.