For more details, check out the blog post, and the paper here: go.aps.org/4aJrftm

We introduce a new 'halting interaction', where individuals stop on encountering others moving in the opposite direction. With this simple addition, we can attain globally ordered collective movement, with just pairwise interactions!

We show, using a model, that a simple addition can circumvent this limitation, and attain globally ordered movement, with just pairwise interactions. The ingredient is 'stop-and-go' movement, a feature seen across taxa in animal locomotion, from locusts to sheep.

Previous work has shown that, in small groups, interacting with just one neighbour is enough to achieve order. However, in large groups, these single-neighbour or pairwise interactions are insufficient, and the group devolves into disordered motion.

In animal collective movement, there is evidence that individuals can interact only with a few neighbours at a time, due to perceptual and cognitive limitations. This begs the question: how many neighbours do you need to interact with, to achieve ordered collective movement?

Here is a blog post on our recently published paper on collective movement with stopping: arshednabeel.github.io/blog/flockin...

(Short thread follows)

Work lead by Yogesh Kumar KC, and mentored by @vishuguttal.bsky.social and Srikanth Iyer.

Our work on collective movement of individuals who can stop is now out in Physical Review E! We show that stopping can lead to ordered collective movement through a surprising new mechanism. go.aps.org/4aJrftm

Bluesky Map Interactive map of 3.4 million Bluesky users, visualised by their follower pattern.

I made a map of 3.4 million Bluesky users - see if you can find yourself!

bluesky-map.theo.io

I've seen some similar projects, but IMO this seems to better capture some of the fine-grained detail

Google's NotebookLM is one of the few times that AI has pleasantly surprised me. Especially with its new feature of creating slide-decks from sources you upload, it's an incredible tool for self-study.

The Company of Biologists 100 logo to the left and QR code to the right. Portrait of Rohini Balakrishnan to the left, text to the right 100 extraordinary biologists Rohini Balakrishnan Rohini Balakrishnan is a Journal of Experimental Biology author, Editorial Advisory Board member and a part of the first cohort of JEB Travelling Fellowship recipients. Rohini Balakrishnan is a Professor at the Indian Institute of Science, India, where she investigates animal communication and bioacoustics. #100biologists #biologists100

This week, we are highlighting Rohini Balakrishnan, a @jexpbiol.bsky.social author, Editorial Advisory Board member and a part of the first cohort of JEB Travelling Fellowship recipients, as an extraordinary biologist. #100biologists

Diagram from “Eco-Evolutionary Dynamics for Finite Populations and the Noise-Induced Reversal of Selection” by Ananda Shikhara Bhat and Vishwesha Guttal (Jan 2025). © University of Chicago

How Randomness Can Flip Evolution: New Study Uncovers Surprising Role of Population Noise

Summary & Analysis by Tahirah Williams of “Eco-Evolutionary Dynamics for Finite Populations and the Noise-Induced Reversal of Selection” by Bhat et al.
www.amnat.org/an/newpapers...

Full House brainstorming about Projects at the Konstanz School of Collective Behavior . What an amazing group of Students . Each student works on a project to be presented at the end of the school @cbehav.bsky.social

I recently learned that people may be using em-dashes (—) as one of the tell-tale signs for AI generated text. Now I have to consciously avoid using them in emails etc.

I liked my em-dashes! 😞

Discovering Stochastic Dynamical Equations from Ecological Time Series Data | The American Naturalist Abstract Theoretical studies have shown that stochasticity can affect the dynamics of ecosystems in counterintuitive ways. However, without knowing the equations governing the dynamics of populations ...

Nabeel et al. present a method to derive models of theoretical ecology from stochastic time series data. This data-driven method may help empirical tests of ecological theories and to discover unknown principles. Read now ahead of print!
www.journals.uchicago.edu/doi/10.1086/...

Oh sorry for the confusion! The purgatory time consisted of many submissions across journals. All things considered, the review process at AmNat was quite pleasant!

Discovering Stochastic Dynamical Equations from Ecological Time Series Data | The American Naturalist Abstract Theoretical studies have shown that stochasticity can affect the dynamics of ecosystems in counterintuitive ways. However, without knowing the equations governing the dynamics of populations ...

After languishing in the peer-review purgatory for over two years, our work on discovering dynamical models from time series data is finally out in @asn-amnat.bsky.social!

www.journals.uchicago.edu/doi/10.1086/...

Vol. 24 - Here is a revised version of your review with improved clarity ChatGPT is not my peer. It should not review my papers.

We finally got a ChatGPT generated review on a manuscript. So I wrote about how we handle these reviews is a sign of whether we have given up on peer review altogether.

Distinct Elements in Streams: An Algorithm for the (Text) Book Given a data stream $\mathcal{A} = \langle a_1, a_2, \ldots, a_m \rangle$ of $m$ elements where each $a_i \in [n]$, the Distinct Elements problem is to estimate the number of distinct elements in $\ma...

Even the full paper is very readable (by CSTheory standards anyway).
arxiv.org/abs/2301.10191

So elegant!
Back in the day when I was a CS masters student, streaming algorithms were of my favorite things in our graduate algorithms course.

I’m probably missing something, but intuitively it looks like A should imply B?

Comparison of lattice-based random walks models with and without interactions between agents.

Do you work with individual-based models of birth, death and movement?

We have a review paper for you, part of a special collection for the journal Interface’s 20th birthday!

doi.org/10.1098/rsif...

This past week, I had a pleasure to attend and teach a tutorial session at the ICTS-ICTP Winter School on Quantitative Systems Biology. Fascinating school, opened my eyes to the amazing world of theoretical community ecology.