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COMPLEX TIME: Adaptation, Aging, & Arrow of Time

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Hallmarks of Biological Failure/MariaRiolo

From Complex Time

Notes by user Maria Riolo (SFI) for Hallmarks of Biological Failure

Post-meeting Reflection

1+ paragraphs on any combination of the following:

  • Presentation highlights
  • Open questions that came up
  • How your perspective changed
  • Impact on your own work
  • e.g. the discussion on [A] that we are having reminds me of [B] conference/[C] initiative/[D] funding call-for-proposal/[E] research group

Interesting conceptual idea organisms traversing a state space with multiple local attractors and one absorbing state (death), and aging as changing that landscape and thus the probability of transitions between states. Even if we just looked at aging as a plain old flattening of the landscape (or accumulation of noise in the landscape/transition probs?), that would already pop out properties like breakdown of homeostasis/loss of resilience to perturbations (previously attracting basins aren't as steep) and a propensity to reach regimes that were previously hard to get to (e.g. cancers). At first glance it seems like flattening the landscape would lead to more variability across the board, more wide excursions to various states, but maybe that's not quite right - I could also picture a scenario where loss of local variability -> landscape dominated by broad features that haven't eroded away -> loss of diversity/flexibility, effectively being left with a small set of wide highways instead of a larger set of little paths.

Related idea came up today: how do "near flat until sudden acceleration of risk" disease incidence v age curves arise from more gradually creeping molecular aging? Possible mechanism could be that idea of gradual landscape change leading to a threshold where falling out of the basin of attraction becomes much more likely. I tried a toy model over lunch: stochastic logistic growth process with gradually declining carrying capacity. What do survival times look like? Turns out they do get that nice elbow property - could imaging evolving how much you invest in repairs to slow the gradual decline tuning that elbow to an appropriate age of "I probably already died by other causes and my expected # of future offspring is low."


Reference material notes

Some examples:

  • Here is [A] database on [B] that I pull data from to do [C] analysis that might be of interest to this group (insert link).
  • Here is a free tool for calculating [ABC] (insert link)
  • This painting/sculpture/forms of artwork is emblematic to our discussion on [X]!
  • Schwartz et al. 2017 offers a review on [ABC] migration as relate to climatic factors (add the reference as well).

Reference Materials