What if birds of a feather flock together, but only at specific group sizes? www.nature.com/articles/s41... This is the focus of our new paper, now published in Nature Communications. We introduce a new network model and show how to model and measure homophily to incorporate group variations.

Late advertisement of our new pre-print: Contact structure and population immunity shape the selective advantage of emerging variants www.medrxiv.org/content/10.1...

🧵1/ A bit late to the party, but I want to introduce a pet project of mine—and my first single-author paper! 🎉 It tackles something that has quietly frustrated me for years: how we measure the similarity of two clusterings/community structures.

Spatiotemporal Activity-Driven Networks arxiv.org/abs/2511.15533

Latest out: Fairness in infectious disease modeling. Great collaboration with Yuhan Li, @ngozzi.bsky.social @mtizzoni.bsky.social www.medrxiv.org/content/10.1...

published pubs.aip.org/aip/cha/arti...

A semi-regular reminder: My colleagues and I are running an interdisciplinary online seminar series called Complex Systems Research Exchange (CREx🦖). sites.google.com/view/cxrex

📢 New reviewed preprint, published by @elife.bsky.social at doi.org/10.7554/eLif.... We study two effects in science funding across 14 different funding programmes from 6 research funders across Europe and North America: (1) The Matthew effect; and (2) and the early-career setback effect. 🧵1/8

Reminder: Last chance to apply for our postdoc positions in polarisation + mental well-being: www.aalto.fi/en/open-posi...

Science isn’t really moving towards equity; institutions are just perfecting the appearance of equity. We need to build an alternative system, says Dolors Armenteras go.nature.com/4nzGhp9

We are hiring multiple PhD and postdocs for two newly funded projects at the intersection of mental health and political polarization at the CS Dept at Aalto, Finland. The PIs are Juhi Kulshrestha, Talayeh Aledavood, and Mikko Kivelä. Full call text and link to apply: www.aalto.fi/en/open-posi...

Celebrating the publication of our big collaborative spatial-social meta-analysis of density-dependent transmission effects, out now in Nature Eco Evo! doi.org/10.1038/s415... (or rdcu.be/eD6eB)

Q: How are resources consumed in transportation networks, and how does this shape the overall functioning of the system? We introduce the minimum-cost percolation framework and apply it to the U.S. air transportation system using publicly available data. 🔗 www.nature.com/articles/s41...

Our paper about discounting the influence of node attributes from detected communities in networks is out in Physical Review E! journals.aps.org/pre/abstract...

Happy to share this long-overdue project! We found that many real-world event sequences follow a surprisingly similar hierarchically structured pattern, and that multi-timescale memory mechanisms can explain this pattern. Feedback welcome! arxiv.org/abs/2508.18281

Our new preprint with @takayukihir.bsky.social is out in arXiv: Takayuki Hiraoka‬ and Hang-Hyun Jo, Hierarchical organization of bursty trains in event sequences, arxiv.org/abs/2508.18281

PNAS: Strength and weakness of disease-induced herd immunity in networks https://www.pnas.org/doi/abs/10.1073/pnas.2421460122?af=R

Eighty years after the atomic bomb was dropped on Japan, we hear from one of the survivors go.nature.com/45pj3e1

This is a huge news to me—that Mendeley Desktop is not going to be discontinued—yet nobody in my timeline seems to be talking about it? blog.mendeley.com/2025/07/09/m...

New paper in PNAS!🎉 doi.org/10.1073/pnas... Is herd immunity to infectious diseases effective when induced by natural infection? Earlier studies have suggested that population heterogeneity makes disease-induced herd immunity more effective than previously thought. Our work challenges this notion.

Spatial cognition is vital for all animals. Humans, in particular, use cartographic knowledge and language to understand the environment beyond what we directly experience. Place names (toponyms) play a key role in this cognitive process as they reflect how we mentally structure geographical space.

On Tuesday, Tarmo Nurmi successfully defended his thesis on multilayer networks. Congratulations, Tarmo!

Latest out in PNAS!! Comparative evaluation of behavioral epidemic models using COVID-19 data. Amazing collaboration with @ngozzi.bsky.social and @alexvespi.bsky.social www.pnas.org/doi/10.1073/...

Our paper has been finally published in PLOS ONE! See doi.org/10.1371/jour...

My bus is delayed, time for another beer

So many interesting talks at #NetSci2025! Here are some of my favorites among contributed presentations I heard today:

Arrived in Maastricht, excited to be attending #NetSci2025 this week! If you're there too, please visit poster #4 by my collaborator, Zahra Ghadiri, during lunchtime on Wednesday. She will tell you about our research, “Epidemic Reproduction Number in Spatial Networks”.

Arrived in Maastricht, excited to be attending #NetSci2025 this week! If you're there too, please visit poster #4 by my collaborator, Zahra Ghadiri, during lunchtime on Wednesday. She will tell you about our research, “Epidemic Reproduction Number in Spatial Networks”.

Cool study showing that the pattern of wrinkles on a finger immersed in water for long time is always the same. doi.org/10.1016/j.jm...

Looking forwards to presenting at NetSci on 3 June. If you're an Early Career Researcher attending the conference, it would be great to see you there #netsci2025

New paper alert 📄🚨 Static network structure cannot stabilize cooperation among large language model agents journals.plos.org/plosone/arti... w @ivanromic.bsky.social @balaraju.bsky.social & al.

📢 We’re hiring! RIKEN iTHEMS has launched a new Mathematical Social Science Team, and we’re looking for researchers to join us. If you're into cooperation, norms, or networks, check out the call! 🔗 www.riken.jp/en/careers/r... Feel free to DM me if you have questions!

Human wounds heal three times slower than those of other primates, including our closest cousins, chimpanzees. This suggests that it's a unique trait we've acquired through evolution. Why would such a seemingly disadvantageous trait have been favored by natural selection? doi.org/10.1098/rspb...

I just learned about loop-else syntax in Python and it made my day! docs.python.org/3/tutorial/c...

*Please repost* @sjgreenwood.bsky.social and I just launched a new personalized feed (*please pin*) that we hope will become a "must use" for #academicsky. The feed shows posts about papers filtered by *your* follower network. It's become my default Bluesky experience bsky.app/profile/pape...

When you have network data with node metadata, how can you use them to improve community detection? One way is to make the communities align with the metadata. In our new preprint, we propose another way: to discount the effects of the metadata from the detected communities. arxiv.org/abs/2502.20083

Me ranting at AI about English words

Researchers studying the movement of crowds at a traditional Spanish festival have shown that densely packed groups of people form swirling ‘vortex’ patterns never before documented in human gatherings https://go.nature.com/40DSmzK

Does costly punishment—paying a cost to reduce an opponent's payoff—help sustain cooperation in indirect reciprocity? Punishment is often seen as a powerful tool, but its effectiveness here is debated. Our new study explores this: sciencedirect.com/science/arti... 🧵

My latest post on a remarkable mathematical CV: kucharski.substack.com/p/the-ten-ye...

How to choose a research question? Choosing which problems to work on is perhaps the hardest and most crucial part of science. It is also an invisible and underrated part.

We have been hearing lots of sad news about research funding in the US! We currently have open postdoc positions here in Finland (these positions come with lots of independence and good compensation). Deadline on 2/2:

The early-career success of academic researchers is better predicted by their publication record during their postdoctoral years than by where they obtained their PhD, according to a study of 45,572 academic careers worldwide. In PNAS: www.pnas.org/doi/10.1073/...

Our recent PNAS about postdocs and their future careers: www.pnas.org/doi/10.1073/...

We're organizing a NetSci'25 satellite workshop on Directed Acyclic Graphs — if you're working on, e.g., citation graphs, pedigrees, causality, temporal-network event graphs, network representations of spacetime, or any other areas where DAGs play a role, please contribute! www.dagshop.xyz

A semi-regular reminder: Together with colleagues from South Korea and Japan, we are running an interdisciplinary online seminar series called Complex Systems Research Exchange (CREx🦖). sites.google.com/view/cxrex

The world has passed “peak child”

They say we never know the value of water until the well is dry. I'm now deeply appreciative of Overleaf and praying for its comeback.

I know complaining about updates is cliché, but wasn’t the old look of the Physical Review website better than the new one?