
Math Reveals the Secrets of Cells’ Feedback Circuitry - pseudolus
https://www.quantamagazine.org/math-reveals-the-secrets-of-cells-feedback-circuitry-20190918/
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achenatx
Finally :) I have a degree in electrical engineering and a degree in
immunology (in the early 90s) and was 100% sure that control systems math
should be applied to biological systems, like the immune system.

Most biologists tend to take very little math (calculus and stats) and dont
even realize that control systems are a thing.

We definitely need more of that cross pollination.

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commandlinefan
> Most biologists tend to take very little math

Wow, really? That's surprising to me. The hardest course I ever took was one I
took for my MSCS in bioinformatics. It seemed very math-heavy, and math-heavy
in ways that I couldn't lean on my past experience to "muscle" my way through.

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adenadel
In my experience, a lot of biologists learning bioinformatics/genomics tend to
learn a specific set of general tools (HMMs, multiple hypothesis testing, PCA,
etc.) and then learn some specific statistical tools that apply to their data
(e.g negative binomial GLMs for RNAseq).

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ncmncm
There is enormous room for original, fundamental, groundbreaking work here.

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signal_space
Highly recommend this text and Uri Alon's work in general for those interested
in diving deeper into this subject.

[https://www.amazon.com/gp/product/1439837171/ref=dbs_a_def_r...](https://www.amazon.com/gp/product/1439837171/ref=dbs_a_def_rwt_bibl_vppi_i0)

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phkahler
>> To minimize the effects of noise, the duo realized, the two controller
molecules must have a very specific relationship: They have to bind to each
other and neutralize each other’s biological activity. One must be the
antithesis of the other.

One more thing they may want to add. A way to break down all these neutralized
pairs and clear them out. Depending that these molecules look like there may
already be something in place to do that, then it's more a matter of ensuring
compatibility rather than making a new clearing mechanism.

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madhadron
There are two major ways that happens. In growing populations of cells, they
are diluted as the cells grow and divide, and there is ongoing recycling of
proteins in the cell. Some are more labile (likely to be grabbed by the
recycling machinery) than others, but it's an ongoing background process.

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hi41
The article talks about negative feedback in the circuitry to maintain
stability. Why can’t the same be achieved using positive feedback in the
biological and psychological realms? Only the sign is different. In the
psychological system the negative feedback back can be thought of as pain. Why
can’t achieve stability through pleasure instead?

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kian
Just to be clear, negative feedback is not giving 'bad feedback', it's taking
an action that 'dampens' a signal as it gets outside of a zone of control to
bring it back in line. Positive feedback would not be pleasure or reward,
positive feedback would be something more akin to a runaway chain reaction or
an avalanche, where the system takes an action that emphasizes a signal as it
gets outside the zone of control.

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madhadron
> The work is backed by a mathematical proof that no simpler answer exists — a
> good indication that natural feedback systems probably work the same way.

On the contrary. It means that you probably won't find anything simpler, but
you will certainly find more complex ones as exaptation drags part of the
system off in a new direction.

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ilaksh
In a very general sense, feedback loops seem important in many areas.

A couple of potential examples: software engineering and animal intelligence.

In software there are loops between the programmer and various levels of the
development process, from compilers to test runners all the way to user
testing and feedback.

A large function of animal intelligence may be to integrate (in a very broad
sense, not mathematically as used in the article) information about the
environment in order to regulate the organism's place in it.

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woodandsteel
My understanding, as someone who is rather scientifically oriented but not a
biologist, is that a living organism is basically an elaborate, multi-level
set of interconnected negative feedback loops. Have I got that right?

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ngneer
Information security is about control, too.
[https://dl.acm.org/citation.cfm?id=2898379](https://dl.acm.org/citation.cfm?id=2898379)

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TeMPOraL
PDF: [http://sci-hub.tw/10.1145/2898375.2898379](http://sci-
hub.tw/10.1145/2898375.2898379).

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dugluak
Wow that robot looks so cool. Wish I can build something like that with a
raspberry pi 3 and a ton of my kid's lego lying around in my house.

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mehrdadn
If you find the robot cool... check this out. :-)
[https://www.youtube.com/watch?v=cyN-
CRNrb3E](https://www.youtube.com/watch?v=cyN-CRNrb3E)

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ncmncm
outstanding!

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selimthegrim
Too bad Arthur Winfree isn’t around to update his book.

