Ulysse Marquis
@ulyssemarquis.bsky.social
📤 53
📥 117
📝 38
looking for order in messy systems statistical physics
reposted by
Ulysse Marquis
Network Science Institute
14 days ago
What makes a city feel alive? A new study in 𝘗𝘕𝘈𝘚 𝘕𝘦𝘹𝘶𝘴, with contributions from
@riccardodiclemente.com
, rethinks urban vibrancy through ecology and retail science. The key idea: cities thrive through activity diversity, much like ecosystems thrive through biodiversity.
tinyurl.com/uuc3cja3
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Ulysse Marquis
physics.soc-ph
16 days ago
On the Meaning of Urban Scaling
https://arxiv.org/abs/2603.30021
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Ulysse Marquis
arXiv cond-mat.dis-nn Disordered Systems and Neural Networks
21 days ago
Ulysse Marquis, Henri Berestycki, Marc Barthelemy: FKPP fronts in quenched random media
https://arxiv.org/abs/2605.14914
https://arxiv.org/pdf/2605.14914
https://arxiv.org/html/2605.14914
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arxiv.org/abs/2604.21437
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Universal Local Roughness from Disorder Crossover in Urban-Front Growth
Urban expansion fronts display a robust local roughness exponent together with strongly dispersed growth and nonuniversal dynamic exponents. We show that this coexistence can arise from a disorder-con...
https://arxiv.org/abs/2604.21437
about 1 month ago
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Two pre-prints out, discussing 1) the dynamical interpretation of cross-sectional exponent in urban scaling
arxiv.org/abs/2603.30021
2) the roughening in deposition models with strong blobs polydispersity
arxiv.org/abs/2604.018...
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https://arxiv.org/abs/2603.300212
2 months ago
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Ulysse Marquis
Tiago Peixoto
2 months ago
I’m happy to share that, as of April 1st, I will be taking on a W3 Professorship in Complex Systems and Network Science at the Goethe University Frankfurt
@goetheuni.bsky.social
.
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www.sciencedirect.com/science/arti...
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Modeling the spatial growth of cities
The growth of cities has traditionally been studied from a population perspective, while urban expansion – its spatial growth – has often been approac…
https://www.sciencedirect.com/science/article/pii/S0370157326001195
2 months ago
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on the x-minute cities
arxiv.org/abs/2603.12122
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Why urban heterogeneity limits the 15-minute city
The `15-minute city' has emerged as a central paradigm in urban planning, promoting universal access to work and essential services within short travel times. Its feasibility-particularly for commutin...
https://arxiv.org/abs/2603.12122
3 months ago
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reposted by
Ulysse Marquis
physics.soc-ph
3 months ago
Mathematical modeling of urban sprawl
https://arxiv.org/abs/2603.08338
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reposted by
Ulysse Marquis
Urban Truth Collective
3 months ago
Suburban Sprawl may seem cheap, but even the costs we CAN count are far too high, and we ALL pay them. HT Smart Prosperity Institute
#UrbanTruth
institute.smartprosperity.ca/library/publ...
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Ulysse Marquis
Geoff Boeing
3 months ago
I recently published a paper in PNAS Nexus with Marc Barthelemy, Alain Chiaradia, and Chris Webster that addresses the problem of urban networks' elevations: they seem simple enough, but modeling them can be tricky. Open-access paper link:
buff.ly/Mt7u2QG
Here's a short summary...
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Ulysse Marquis
Tiago Peixoto
3 months ago
New on the arxiv: “Graphs are maximally expressive for higher-order interactions”
arxiv.org/abs/2602.16937
We clarify central misconceptions in the recent literature on "higher-order networks". w/
@piratepeel.bsky.social
,
@manlius.bsky.social
, and
@thilogross.bsky.social
Explainer 🧵: 1/N
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Graphs are maximally expressive for higher-order interactions
We demonstrate that graph-based models are fully capable of representing higher-order interactions, and have a long history of being used for precisely this purpose. This stands in contrast to a commo...
https://arxiv.org/abs/2602.16937
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arxiv.org/abs/2602.16937
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Graphs are maximally expressive for higher-order interactions
We demonstrate that graph-based models are fully capable of representing higher-order interactions, and have a long history of being used for precisely this purpose. This stands in contrast to a commo...
https://arxiv.org/abs/2602.16937
3 months ago
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reposted by
Ulysse Marquis
Arthur Charpentier
4 months ago
"L’écosystème du bruit et la fabrique de l’autorité"
freakonometrics.hypotheses.org/88516
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L’écosystème du bruit et la fabrique de l’autorité
Depuis quelques moi, j’essaye d’écrire un billet sur le greenwashing (“écoblanchiment” comme on dirait au Québec). Et forcément, ça prend du temps, parce que j’ai souvent tendance à me perdre dans tes...
https://freakonometrics.hypotheses.org/88516
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journals.aps.org/pre/abstract...
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Scale-free points-of-interest distribution in a city emerging from homogeneous Poissonian-point processes
Urban systems often exhibit scale-invariant properties, with power-law distributions observed in various spatial and temporal patterns of human behavior. A prominent example is the distribution of commercial activities and other points of interest (POIs) across cities. However, the mechanisms by which such heavy-tailed behaviors emerge from local urban dynamics remain poorly understood. In this work we demonstrate that global inhomogeneity in the spatial distribution of POIs can arise from the aggregation of locally homogeneous processes. Using Foursquare data from the city of Bologna, we show that POI distributions exhibit clear power-law scaling when analyzed at city scale. We develop a theoretical framework in which this behavior naturally emerges from spatial clusters defined by shared intensity levels across disjoint areas, rather than spatial contiguity. By analytically and empirically linking these local processes to the observed global distribution, we provide a generative explanation for the emergence of scale-free patterns in urban commercial structure. To further relax the assumptions underlying the purely spatial model, and to account for the empirical observation that areas with similar activity intensity can be spatially disjoint, we introduce a hybrid hierarchical approach that combines spatial clustering with statistical heterogeneity across regions of comparable density, modeled via Poisson mixtures. This enables us to capture real-world deviations from local regularity while preserving interpretability. Our findings highlight a key insight: complex global phenomena in cities can arise from the spatial superposition of simple, locally uniform dynamics. This connection between microlevel homogeneity and macroscale complexity offers tools for interpreting, modeling, and classifying urban space.
https://journals.aps.org/pre/abstract/10.1103/c8jr-3twz
4 months ago
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reposted by
Ulysse Marquis
NetScience
4 months ago
Network map of Bluesky users
flowingdata.com/2026/02/11/n...
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Network map of Bluesky users
Theo Sanderson visualized the network of 3.4 million Bluesky users, placed by follow patterns. It is searchable and interactive. If you zoom in close enough, you can find our tiny pocket of data vi…
https://flowingdata.com/2026/02/11/network-map-of-bluesky-users/
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reposted by
Ulysse Marquis
Marco Mancastroppa
4 months ago
Another new preprint on group adaptation! 📣 Great joint work w/
@martonkarsai.bsky.social
and
@alainbarrat.bsky.social
! Can adaptive behaviors driven by group interactions be more effective and less costly than pairwise ones? How do their adaptive mechanisms differ?
arxiv.org/abs/2602.05915
🧵 1/7
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Higher-order adaptive behaviors outperform pairwise strategies in mitigating contagion dynamics
When exposed to a contagion phenomenon, individuals may respond to the perceived risk of infection by adopting behavioral changes, aiming to reduce their exposure or their risk of infecting others. Th...
http://arxiv.org/abs/2602.05915
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www.siam.org/publications...
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The Physics of Surfaces: Why City Growth is So Rough | SIAM
A novel surface physics-based approach extracts several universal properties from urban data to account for spatial irregularities in city structure.
https://www.siam.org/publications/siam-news/articles/the-physics-of-surfaces-why-city-growth-is-so-rough/
4 months ago
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Ulysse Marquis
Minsuk Kim
4 months ago
Finally, our paper is published in Physical Review E! Surprisingly, the anomalous network-dependent properties observed in ordinary percolation are washed out by the shortest-path-percolation process! An updated arXiv preprint will be available soon as well. 🔗:
journals.aps.org/pre/abstract...
add a skeleton here at some point
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reposted by
Ulysse Marquis
Berlin School of Economics
4 months ago
🏙️ The
#Economics
of
#Architecture
@ahlfeldt.bsky.social
, Elisabetta Pietrostefani & Ailin Zhang bring architectural quality into urban & welfare economics, documenting spillovers, heterogeneous preferences & a coordination problem in design investment. 👇
berlinschoolofeconomics.de/insight/the-...
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And out today !
journals.aps.org/pre/abstract...
add a skeleton here at some point
5 months ago
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reposted by
Ulysse Marquis
Tiago Peixoto
6 months ago
Public service announcement: this
@firefox.com
extension seems to work as intended:
addons.mozilla.org/en-US/firefo...
If anyone knows of a similar workaround for google search on android, please let me know.
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Hide Google AI Overviews – Get this Extension for 🦊 Firefox (en-US)
Download Hide Google AI Overviews for Firefox. Hide annoying Google AI Overviews.
https://addons.mozilla.org/en-US/firefox/addon/hide-google-ai-overviews/
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reposted by
Ulysse Marquis
UCL Bartlett Centre for Advanced Spatial Analysis (CASA)
6 months ago
Just published in Nature Cities, a study led by recent CASA PhD graduate Andrew Renninger advances our understanding of urban inequality by focusing on experienced socioeconomic segregation, or daily encounters between individuals of differing socio-economic groups.
www.nature.com/articles/s44...
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reposted by
Ulysse Marquis
UCL Bartlett Centre for Advanced Spatial Analysis (CASA)
6 months ago
CASA staff Philyoung Jeong and Dr Duncan Smith have published a new working paper on accessibility to cycle routes in London, examining new cycling indicators for tracking cycle network development, gaps in the network and challenges faced by vulnerable cyclists.
discovery.ucl.ac.uk/id/eprint/10...
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Thrilled to share my latest paper
arxiv.org/abs/2512.046...
, accepted at PRE! It challenges a critical assumption from network science : that networks are built bottom-up from nodes. In many spatially embedded networks, this is simply not true : networks are built upon lines and nodes only happen...
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Diffusive geodesics wandering in networks of rigid chains
We introduce an ensemble of spatial networks built from the junctions of hindered-rotation chains, incorporating directional correlations between bonds, an aspect ignored in the standard network model...
https://arxiv.org/abs/2512.04682v1
6 months ago
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reposted by
Ulysse Marquis
Rafael Prieto-Curiel
6 months ago
In our latest paper, with colleagues from the World Bank, we quantified how urban form shapes water access. Compact city growth could deliver piped water to 220 million more people and sewage services to 190 million more people in Africa, Asia, and Latin America. 💧🏙️
www.nature.com/articles/s44...
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reposted by
Ulysse Marquis
NetScience
6 months ago
Recurrent visitations expose the paradox of human mobility in the 15-Minute City vision
arxiv.org/abs/2509.00919
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Recurrent visitations expose the paradox of human mobility in the 15-Minute City vision
In the transition towards sustainability and equity, proximity-centred planning has been adopted in cities worldwide. Exemplified by the 15-Minute City (15mC), this emerging planning paradigm assumes ...
https://arxiv.org/abs/2509.00919
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reposted by
Ulysse Marquis
UCL Bartlett Centre for Advanced Spatial Analysis (CASA)
6 months ago
CASA research in
@nytimes.com
: Ollie Ballinger built software to track naval vessels via open-source satellite data, revealing patterns in Caribbean maritime activity. Read the full story:
www.nytimes.com/2025/11/21/w...
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Satellite Data Reveals How the U.S. Navy Is Deployed Near Venezuela
https://www.nytimes.com/2025/11/21/world/americas/us-navy-venezuela-satellite-data.html?unlocked_article_code=1.208.d0hC.nxvv3V9uaJeA&smid=url-share
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reposted by
Ulysse Marquis
Rafael Prieto-Curiel
7 months ago
Large cities are often assumed to be more violent, but our review shows there’s nothing universal about urban violence. In our new study,
@ronaldomenezes.bsky.social
and I show that isolated cities tend to experience higher rates of violence against civilians.
www.nature.com/articles/s41...
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reposted by
Ulysse Marquis
Tiago Peixoto
7 months ago
This level of blatant dishonesty baffles me. I'm seeing this more and more. Do people *want* to ruin their reputation?
add a skeleton here at some point
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www.bbc.co.uk/weather/arti...
www.lavoixdunord.fr/1645503/arti...
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Northern Lights set to dazzle UK once again due to possible 'severe' geomagnetic storm
The Northern Lights have been shining over the UK and there is another chance to see them Wednesday as Elizabeth Rizzini and Helen Willetts explain.
https://www.bbc.co.uk/weather/articles/cpv13jpmxw7o
7 months ago
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Great read
journals.aps.org/rmp/abstract...
(I also recommend the quick lecture as a teaser
youtu.be/7WsMEL3Q0RI?...
)
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Statistical mechanics for networks of real neurons
Our ability to perceive, think, or act relies on coordinated activity in large networks of neurons in the brain. This review examines recent progress in connecting ideas from statistical physics, such...
https://journals.aps.org/rmp/abstract/10.1103/jcrn-3nrc
7 months ago
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reposted by
Ulysse Marquis
physics.soc-ph
7 months ago
Metros reduce car use in European cities but trams do not
https://arxiv.org/abs/2511.08280
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reposted by
Ulysse Marquis
Mark A. Hanson
7 months ago
We wrote the Strain on scientific publishing to highlight the problems of time & trust. With a fantastic group of co-authors, we present The Drain of Scientific Publishing: a 🧵 1/n Drain:
arxiv.org/abs/2511.04820
Strain:
direct.mit.edu/qss/article/...
Oligopoly:
direct.mit.edu/qss/article/...
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reposted by
Ulysse Marquis
Richard McElreath 🐈⬛
11 months ago
How can we reform science? I have some ideas. But I am not sure you’ll like them, because they don’t promise much.
elevanth.org/blog/2025/07...
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Which Kind of Science Reform
What hope is there for science reform, if we can't agree on what to reform? Right now, principles are more important than practices.
https://elevanth.org/blog/2025/07/09/which-kind-of-science-reform/
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Our work on the dynamics of urban expansion just got published in the Physical Review Letters !
journals.aps.org/prl/abstract...
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Universal Roughness and the Dynamics of Urban Expansion
Urban sprawl reshapes cities, yet its quantitative laws remain elusive. Analyzing built-up expansion in 19 cities (1985--2015) with tools from surface growth physics in radial geometry, we reveal anis...
https://journals.aps.org/prl/abstract/10.1103/rlkq-t36n
7 months ago
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Ulysse Marquis
Arthur Charpentier
7 months ago
"In the 1940s, when the French mathematician Jacques Hadamard asked good mathematicians how they came up with solutions to hard problems, they nearly universally answered that they didn’t think in words; neither did they think in images or equations"
www.henrikkarlsson.xyz/p/wordless-t...
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When is better to think without words?
Non-verbal, blurry thinking is faster and can search in a broader way, but it is more error-prone than verbal thought.
https://www.henrikkarlsson.xyz/p/wordless-thought
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Ulysse Marquis
NetScience
8 months ago
Principled Model Selection for Stochastic Dynamics
link.aps.org/doi/10.1103/...
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Principled Model Selection for Stochastic Dynamics
Complex dynamical systems, from macromolecules to ecosystems, are often modeled by stochastic differential equations. To learn such models from data, a common approach involves sparse selection among ...
http://link.aps.org/doi/10.1103/ltdt-hvh7
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reposted by
Ulysse Marquis
physics.soc-ph
8 months ago
Modeling the spatial growth of cities
https://arxiv.org/abs/2510.03045
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reposted by
Ulysse Marquis
physics.soc-ph
8 months ago
Universal Model of Urban Street Networks
https://arxiv.org/abs/2509.21931
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Ulysse Marquis
Minsuk Kim
9 months ago
Strikingly, the shortest-path percolation homogenizes scale-free networks before the phase transition, resulting in the same universality class as the Erdős–Rényi Networks! Check out our new preprint on arXiv:
arxiv.org/abs/2509.09142
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Shortest-path percolation on scale-free networks
The shortest-path percolation (SPP) model aims at describing the consumption, and eventual exhaustion, of a network's resources. Starting from a graph containing a macroscopic connected component, ran...
https://arxiv.org/abs/2509.09142
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Ulysse Marquis
physics.soc-ph
9 months ago
From lines to networks
https://arxiv.org/abs/2509.07951
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Ulysse Marquis
Diego Rybski
9 months ago
Looks more complicated than it is. In our recent study
journals.plos.org/plosone/arti...
we search for an optimum city size, minimizing both urban carbon emissions and urban heat island (constraint: fundamental allometry). It turns out that given the known UHI parameters such optimum does not exist.
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reposted by
Ulysse Marquis
Complex Human Behaviour Lab
9 months ago
Wide coverage of social media and disinformation analysis yesterday from our lab at the
@css-conference.bsky.social
, with four talks presenting our works associate to the European projects
#AI4TRUST
#AICODE_EU
#HATEDEMICS
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reposted by
Ulysse Marquis
Complex Human Behaviour Lab
9 months ago
Also seen yesterday at
@css-conference.bsky.social
a work on reinforcement learning applied to ants behaviour by Alessio Pitteri, our study of the historical evolution of EU projects by
@verorsanigo.bsky.social
and the study on Coordinated Behavior by
@elisamurators.bsky.social
#CCS2025
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New pre-print out ! Work led by
@eleandre.bsky.social
, in collaboration with M. Napolitano and
@ricgallotti.bsky.social
. Using Foursquare data from Bologna, we find that the distribution of POIs follows a clear power-law pattern at the city scale. To explain this, we introduce a framework where ...
add a skeleton here at some point
9 months ago
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reposted by
Ulysse Marquis
physics.soc-ph
9 months ago
Scale-free Points-of-Interest Distribution in a City Emerging from Homogeneous Poissonian-point Processes
https://arxiv.org/abs/2509.01699
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reposted by
Ulysse Marquis
Complex Human Behaviour Lab
9 months ago
Yesterday was our first day at
@css-conference.bsky.social
in Siena 🇮🇹. We presented on Telegram data collection
@elisamurators.bsky.social
, city growth
@ulyssemarquis.bsky.social
and urban traffic (Alberto Amaduzzi). Excited for 5 more talks today!
#CCS2025
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reposted by
Ulysse Marquis
Alessandro Vespignani
9 months ago
Very interesting study on social contagion applied in a historical context by
@szapperi.bsky.social
and collaborators. Powerful example of where good historical data can lead us in the future.
www.nature.com/articles/s41...
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Epidemiology models explain rumour spreading during France’s Great Fear of 1789 - Nature
Epidemiological methods are used to show that the Great Fear of 1789, a series of peasant insurrections in rural revolutionary France, was driven by deliberate political action rather than spontaneous...
https://www.nature.com/articles/s41586-025-09392-2
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