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COMPLEX TIME: Adaptation, Aging, & Arrow of Time

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Dynamic Multi-System Resilience in Human Aging/RaviVaradhan

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Notes by user Ravi Varadhan (Johns Hopkins Univ.) for Dynamic Multi-System Resilience in Human Aging

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

Alfonse Hoekstra's discussion of multiscale resilience was fascinating to me. The network simulation models of Dervis and Peter Hoffman were very interesting and provide useful insights, but to mimic the complexity of human physiology, we would need hierarchically structured networks. I wonder if there are some invariance principles in multi-scale resilience that could reduce the degree of complexity of this type of modeling. The principles and results of hierarchy theory could be relevant here.

Sanne's talk on DIORs (dynamic indicators of resilience) was also quite interesting. There are several open questions here: how to model temporal autocorrelation; how to handle non-stationary time series; how to do systems identification with DIORs, i.e. how can we predict responses of frail/nonfrail using estimates of DIORs. I also think the idea of reactive tuning to stimulus can be examined using novel metrics of DIORs. I would be interested in exploring these ideas in my work!

The second day's talks were also very interesting. Heather's case history was captivating, highlighting the challenges of treating a human being as a complex physiological system. I liked her point that we need to observe and let the system tell us what needs to be done. Ingrid's talk was very informative on the modeling of complex ecological systems. Porter's talk on the resilience of the Pueblo Indian nation to colonization was very educational for me. I can relate to my own Hindu/Indian culture's resilience in having survived several invasions and colonization over the centuries. The idea of axiology, the systems of values which provide the core resilience to a culture, was most interesting. Warren presented some exquisite data on mouse resilience. To me, tlis hehighlighted the huge potential of using mouse models to develop a comprehensive modeling framework for resilience.

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).

The volume by Howard Pattee entitled "Hierarchy Theory; The Challenge of Complex Systems.", which was published in 1973 could be very relevant to the work on multiscale resilience that Alfonse Hoekstra presented.

Reference Materials

Title Author name Source name Year Citation count From Scopus. Refreshed every 5 days. Page views Related file
Stimulus-response paradigm for characterizing the loss of resilience in homeostatic regulation associated with frailty3 R. Varadhan, C. L. Seplaki, Q. L. Xue, K. Bandeen-Roche, L. P. Fried Mechanisms of Ageing and Development 2008 81 4
Hierarchy theory: the challenge of complex systems2 H.H. Pattee 1973 0 5

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Dynamical systems approach to studying resilience in older adults

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