What is emergence, after all? New PNAS Nexus paper: academic.oup.com/pnasnexus/ar.... In this paper, I clarify the scientific meaning of emergence as a measurable and physically grounded phenomenon through concrete examples, such as temperature, magnetism, and herd immunity in social networks.

If you have an Iranian colleague or friend, this is likely how they feel theses days:

We're already in the phase that each of us (Iranians) by now know someone killed/injured in our circle of friends/family. And this is despite the continued internet blackout, when millions haven't still managed to hear from their family/friends since Thursday, January 8th. This tells a lot ... 😥😥

How did we decide to call a tree “tree”? A bird “bird”? Not now, but in the early days, when there could have been different ways to name or define something. On Language & Poetry | A short post I wrote over the Christmas holidays; abbas.sitpor.org/2025/12/28/o...

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.

Science is supposed to know no borders, until every major conference in my field picks the most hostile country to travel to as its venue 💆🏼 #Epidemics10 #NetSci2026 #CCS2026 #IC2S2 🇺🇸

“I have always tried to live in an ivory tower; but a tide of shit is beating at its walls, threatening to undermine it.” Doing science in contemporary academia, with its endless pressure to please grant committees, often feels like this Flaubert’s complaint in an 1872 letter to Turgenev.

What you expect the least from the reviewers and the editor is exactly checking for the main claims!

Being in #academia as someone not from the global north be like: #phdchat #phdlife

“Physicists are very good and famous for getting the right answers for the wrong reasons.” Why? Here’s a clue: noisy philosophizing! Sean commenting on Nima's talk, Two Cheers for Shut Up and Calculate, at the Natural Philosophy Symposium 2025

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...

We should switch from paper to screen posters—more eco-friendly and far more engaging. Elisa’s poster already showed us how creative this can be. @elisamurators.bsky.social @cssociety.bsky.social

Thank you for this opportunity. The slides of my talk & the preprint are available at abbas.sitpor.org

Excited to present 2 of our recent works at @css-conference.bsky.social “Social & Special Landscape of Covid-19 Immunity in Denmark” - Tue at 15:30, Room 13 - Thu at 12:30, Old Chapel Room “Homophily Within and Across Groups” - Thu at 10:30, Room 13, CSS Satellite

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

@jsaramak.bsky.social you will love this! Permanent link to this comic: xkcd.com/833/

All the keynote recordings are available now, enjoy! www.youtube.com/playlist?lis...

AI & Public Health: Between Hype and Hope — Interview with Samir Bahtt youtu.be/L-_pFPOZvV0 From outbreak forecasting to shaping public policy, AI promises transformative impacts—but what are its true capabilities and limitations? @sjbhatt.bsky.social

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.

What if #herd_immunity isn’t just about how many people are immune, but how they’re 'spatially' connected? Our new PNAS paper explores this concept. We show how the topology and geometry of social networks influence the dynamics of herd immunity, whether it arises from infection or #vaccination. 1/2

1/3 What happens if one repeatedly retrains a machine on data primarily generated from itself? For example when students use LLMs to write their essays that they then put online. And then profs use LLMs to write a paper on that topic and so on 😎 arxiv.org/abs/2506.20623

What is #emergence, after all? arxiv.org/abs/2507.04951 We unpack its meaning across science & philosophy, drawing on examples ranging from physics to bird flocking & epidemics. We feature how #herd_immunity emerges as immune individuals form overlapping firewalls that grow into a dominant shield.

My "Math, Revealed" series is freely available to anyone -- no paywall! -- in the thread below.

Are you interested in doing a PhD in data science in Denmark? The Danish Advanced Research Academy (DARA) has open PHD calls 👇 Reach out to me if you are interested in 1) ML/AI robustness 2) Algorithmic fairness 3) Intersection of Climate change and human behavior daracademy.dk/fellowship/f...

Presented our work with @c0rrad0.bsky.social, @bolozna.bsky.social, and Barbara Keller on user behavior change after cross-party interactions at #ICWSM today! Was a great experience and got a lot of interesting questions 🙌 Also: currently looking for postdoc opportunities - happy to chat!

@sunelehmann.com got me thinking: Are there things that will always remain beyond human understanding, but not for AI? Is there a cognitive upper bound for us—due to our biology—much like a cat can't grasp the mathematics of spacetime curvature? Oh, and the reference totally sealed the deal 😄

Today was the opening of the @icssi.bsky.social in Copenhagen—a remarkable gathering. But, for the first time in my life, I found myself unable to hear a word in a conference. My mind remained fixed—utterly and immovably—on the faces of those I love in #Iran. 1/3

In this episode, @jsaramak.bsky.social shares his personal journey into Network Science. Jari talks about his motivation and research methods as well as how he selects interesting scientific questions. He emphasizes the importance of collaborative partnerships. youtu.be/HwdZS6Fy8X8

Hurray! 🎉 @arash.network (left) is the 24th recipient of the Zachary's Karate Club CLUB prize. For his talk @netsciconf.bsky.social NetSci 2025, he was entrusted with the illustrious trophy 🏆 from @nwlandry.bsky.social #networkscience networkkarate.tumblr.com

Cool hypergraph approach for modeling homophily explicitly at each interaction size! Samantha told us how shifting homophily across hyperedge sizes can amplify inequality in who gets timely information—a perfect hypergraph companion to our clique-layer story. arxiv.org/abs/2412.07901 #netsci2025

If you're looking for a quite handy multitype branching process framework for modeling diffusion in networks with communities check this work by @davidjpos.bsky.social and friends. @netsciconf.bsky.social #netsci2025

🎶 Temporal networks as music? Jari’s audio demo makes temporal networks audible—and it’s oddly mesmerizing. Wild stuff—hear it for yourself and find more here: jarisaramaki.fi/2024/03/19/t... @jsaramak.bsky.social @netsciconf.bsky.social #netsci2025

#NetSci2025 has a fun game to boost the poster session . . . as if that should be needed: petterhol.me/2022/12/20/t...

If Petter's talk sparked your curiosity, his blog will feed it: petterhol.me/blog And here's a great interview on why and how he writes: youtu.be/Wtjo7eWE76E @pholme.bsky.social deserves a best blog award @netsciconf.bsky.social!

Homophily isn’t a uniform property—it varies within and across groups. Time to model that properly! Interested and at #NetSci2025? See you at 👇 - Tue at 15:00, Network Geometry Satellite, FPN Groene zaal or - Wed at 17:30, Multilayer Networks Parallel Session, 0.10 Sydney @netsciconf.bsky.social

The US has long been an uneasy and unfair conference venue for researchers not from the global north! This time is more inclusive, tho! You know, "Then they came for the Jews, And I did not speak out. Because I was not a Jew. Then they came for me, And there was no one left, To speak out for me"

DAGshop is almost here — less than a week to go! If you’re at NetSci, come explore the connections between temporal networks, causality, spacetime, quantum gravity, and more. dagshop.xyz

I'm keynoting this fika-to-fika* workshop in Lund today. Free to participate with registration. www.ai.lu.se/2025-05-27 * peak Sweden?

IceLab Camp: FREE #TRAINING for #PhD students and #Postdocs eager to explore science across boundaries! Learn how to ask questions, craft interdisciplinary research proposals & have fun doing it. September 23–26 near Umeå Apply by June 9 www.umu.se/en/icelab/ca... #complexsystems #complexityschool

🚨 Just 1 week to go! Join us in London 🇬🇧 on May 16 for the NetPlace Workshop on Networks & Physics! Keynotes, collabathon, ERC-style pitches & more 🧠⚛️💥 🆓 Registration is free 💸 Travel/accommodation support available for those who register by Friday May 9 👉 netplace.site/event/netpla...

We had a unique and inspiring symposium on infectious disease epidemiology at Stockholm University. Tnx to the organizers, speakers, and all attendees for the engaging and fruitful discussions. You can view my slides here: lnkd.in/db8ZFw5X

Now that #AcademicTwitter is fading and some of us have moved here, I’m thinking of positive cultural improvements, like sharing the actual insights from the talks we attend! I’d love to see more than just the celebrity cameo in my feed.

"The mixture of vagueness and sheer incompetence is the most marked characteristic of modern English prose, and especially of any kind of political writing." George Orwell's 1946 essay on Politics and the English Language www.orwellfoundation.com/the-orwell-f...

I am hiring PhD students and Postdocs to join me in beautiful Copenhagen. Together, we will develop data science methods to improve epidemic preparedness. Copenhagen is amazing, salary is good, we have plenty of funding, and a great community. Read more..: candidate.hr-manager.net/ApplicationI...

There are days in life that shake you. I’m shattered 💔 to share that I just found out that the US Government terminated my 2024 NIH Director’s Early Independence Award (~$2 million), threatening my long-promised assistant professor job at Columbia University & academic career... 1/🧵

Writing a paper be like spending 8 hours reading 6 papers to write one sentence citing 2 references—then deleting it the next morning. "A carpenter does not sit on his shavings. You have to be ruthless with your material! If it takes attention away from [the main message], throw it away at once."

Walk down the street of any city, and look around you. What you've got to remember is what you're looking at is also you. Everyone you're looking at is also you. You could be that person. You could be that monster, you could be that cop. And you have to decide, in yourself, not to be. J. Baldwin

Charting the Uncharted: Interview with Sune Lehmann youtu.be/hbbjq54nQO8 With @sunelehmann.com, we explore his unconventional journey from traditional physics to the wild world of social data science and interdisciplinary research.

IMO, the real issue isn't the validity or reliability of the principle but its misinterpretation in practice. Occam's razor is only relevant when two models have equal explanatory power, serving as a tie-breaker. If one model predicts better, then Occam's razor doesn't apply.

Interested in using data on human behaviour to understand and predict epidemics? Come do a PhD with us! Deadline 7 March – please get in touch if interested! www.lshtm.ac.uk/study/fees-a...