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Fernando Pérez

@fernandoperez.org
1.7K followers 685 following 136 posts

Open source, open science, AI in science for earth/ice and healthcare. IPython creator, @projectjupyter.bsky.social and 2i2c.org co-founder. Prof @ UC Berkeley Stats, director of @ucbids.bsky.social, co-director @schmidtdse.bsky.social; LBL scientist.

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Fernando Pérez @fernandoperez.org · 15/06/2026
Congrats to @serenabonaretti.bsky.social or the physical publication of her awesome "Learn Python with Jupyter" 📙 👏 🎉 , and thanks for sending me a physical copy to Berkeley! The weaving of Python+Jupyter and how to use them to think is wonderful. We're fortunate to have Serena in our community!
Photo of Fernando Pérez holding the book "Learn Python with Jupyter" by Serena Bonaretti, with a metal print of the Jupyter logo in a rear blue wall, above a window with shades partially drawn.
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Fernando Pérez @fernandoperez.org · 05/01/2026
They state both the instructor (blog author) and a TA manually graded all exams:
The grading was stricter than my own default. That's not a bug. Students will be evaluated outside the university, and the world is not known for grade inflation. (Just in case you are wondering, I graded all exams myself and I asked the TA to also grade the exams; we mostly agreed with the LLM grades, and I aligned mostly with the softie Gemini. However, when examining the cases when my grades disagreed with the council, I found that the council was more consistent across students and I often thought that the council graded more strictly but more fairly.)
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Fernando Pérez @fernandoperez.org · 26/09/2025
In 2023, she led NASA, then federal agencies, to make public, coordinated commitments to open science that were incredibly well thought out. While open.science.gov doesn't resolve now, it was an example of how to guide policy to benefit all of science and society. www.nature.com/articles/d41...
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Fernando Pérez @fernandoperez.org · 26/09/2025
Huge congratulations to NASA's @cgentemann.bsky.social for the #AGU2025 Open Science Recognition Prize!!! 🎉🎊🚀 Chelle has been a steadfast leader in open science, from data, to code, infrastructure, policy and education. This could not be more highly deserved! www.agu.org/honors-home/...
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Fernando Pérez @fernandoperez.org · 30/07/2025
Interested in open source, @jupyter.org - friendly tools, workflows and ideas for #earthscience and coming to @agu.org #AGU25? Since AGU's website collapse led an abstract deadline extention til tomorrow, please submit a proposal for our session! events.geojupyter.org/conferences/...
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Fernando Pérez @fernandoperez.org · 12/04/2025
Amazing science meets art event at Berkeley today! NASA Parker Solar Probe data and science becomes music at the campus Campanile carillon. Cc @cgentemann.bsky.social, Greg Niemeyer. www.suncarillon.org
Woman presenting slide about NASA science fleetFour people standing in front of Parker Solar Probe poster and sun globe. People outside Berkeley campanile Group in front of Parker Solar Probe poster
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Fernando Pérez @fernandoperez.org · 07/03/2025
That felt good! Great speeches from the Berkeley community, ranging from Nobel Laureate Jennifer Doudna to undergraduate student leaders. Amazing energy in defense of science, and it felt good to do something positive, even if it's just a small step. Below is the text I read. #StandUpForScience !
Stand Up for Science @ Berkeley
Fernando Pérez. Mar 07, 2025.
Hello, I am Fernando! I was trained as a physicist, and today I am a professor in Statistics; I also direct the Berkeley Institute for Data Science and co-direct the Data Science and Environment Center, that I both co-founded. It’s an honor to be here today, but I am very sad.

I am sad, because science is under attack. And science is deeply tied to our humanity, so our very humanity is under attack. Science is driven by curiosity, by our need to make sense of the world around us, and it gives both power and meaning to our existence. Historically, the US has been the most fertile ground for this enterprise that also brings immense social and economic value. Now we must fight to save it.

I am an immigrant: I was born and raised in Colombia, a country ravaged in the 80s and 90s by drug and guerilla violence. I wanted to study physics, and I had the option to go to Europe or the US. Having lived in both, I chose to come here. Why? Because it was:
A more open and welcoming society, where immigrants from all nations and cultures had the opportunity to build new futures.
A country whose dedication to first-rate science had never wavered, regardless of changes in politics or administrations.

Thanks to US scientific institutions, I was able to build a weird career: I published papers, but I also built stuff. In 2001 I started writing open source software for science–something called IPython that later, with work from many others, became Project Jupyter. Many of you at Berkeley have used Jupyter and scientific tools I helped build. Many companies also have products based on these tools.But this career, driven by curiosity and producing basic science and tools that benefit millions for free, would be impossible now. I am grateful to the US for what it helped me do, but I am sad that much of the country now wants to destroy this jewel.

Why do they attack science? Fascists can’t tolerate science because it is independent. Because while imperfect, scientists seek answers where the evidence will lead them regardless of what politicians want. Fascists demand obedience and control, and science strives to follow nature where it leads.

To defend our humanity, to defend this incredible endeavor that belongs to all, we must stand up and defend its core values of curiosity, exploration and independence.

This also means defending the humanity of all. Science needs all to succeed, regardless of gender, ethnicity or other identity. In particular, we as scientists must show more courage and integrity than our politicians, and stand up for the rights of trans persons to exist, to live in peace and to simply be themselves.  Fascists have chosen to target trans persons precisely because they are a small, vulnerable minority. They are betting the rest of society will abandon them. We can’t–if we abandon the rights of trans people to live with dignity, we abandon the very humanity at the heart of science, and we will forfeit any moral standing to defend the rights of other groups.

That’s what the fascists want: to crack the moral foundation we stand on, so that we can’t fight back with the power of science, the power that lets us edit genomes or take images of black holes.

So let’s fight back! With science, but with humanity too, by protecting science as open for all.

Thank you!Large group of people sitting and standing in an open plaza, with building with columns in the background. A sign that says "Science" and has some smaller text is visible in the front.Group marching on the UC Berkeley campus, below Sather Gate.
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Fernando Pérez @fernandoperez.org · 07/03/2025
It's today, T-3h! If you're in the East Bay and care about science or education (i.e. if you care about living on this planet in any form 😃), join us, 11:45 at Upper Sproul! And if you're elsewhere, look up a local event in your area, there's a LOT happening today! www.standup4scienceberkeley.com
Map of Northern hemisphere with many blue place markers.
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Fernando Pérez @fernandoperez.org · 06/03/2025
Proud to join this awesome lineup of speakers in defense of science and education at the #StandupForScience2025 Berkeley event tomorrow - join us if you're in the East Bay (there's also an event in SF and one in Sacramento)! www.standup4scienceberkeley.com
A series of headshots for speakers at the StandUpForScience Berkeley event, March 7, 2025.A series of headshots for speakers at the StandUpForScience Berkeley event, March 7, 2025.A series of headshots for speakers at the StandUpForScience Berkeley event, March 7, 2025.
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Fernando Pérez @fernandoperez.org · 06/03/2025
Delighted and proud to speak on Friday at the Berkeley #StandUpForScience march. 📢🔭🧑‍🔬🥼🔬🧪📡🛰️🌎 Science and education are under attack, but standing together we can resist ✊ Huge thanks to the organizing team for the opportunity to speak! www.standup4scienceberkeley.com
Portrait of man wearing glasses with caption:

Fernando Pérez​

Associate Professor of Statistics, UC Berkeley; Faculty Scientist, Lawrence Berkeley National Laboratory
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Fernando Pérez @fernandoperez.org · 06/03/2025
Berkeley scientists, students, faculty, staff - there's a local #standupforscience2025 event on campus on Friday! Not only science, but the entire idea of independent inquiry and higher education, are under major attack. We need to respond and defend this mission. www.standup4scienceberkeley.com
Standup for Science poster for Berkeley March 7 event, with QR code and brief schedule. Image shows the Statue of Liberty, blue and red color scheme.
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Fernando Pérez @fernandoperez.org · 18/02/2025
I'm sure they'll reopen soon under new management... It will be beautiful, it will have beautiful golden toilets everywhere...
Face of Half Dome, in Yosemite National Park, with the letters T, R, U, M, P superimposed with a marquee styling.
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Fernando Pérez @fernandoperez.org · 18/02/2025
Sweet! That was very smooth and fast! Love it that you have already a JupyterGIS example 🌎🚀 Will definitely be playing a lot more with this soon!
Screenshot of Jupyter Notebook using JupyterGIS to load data and render it over a map of central and north America.
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Fernando Pérez @fernandoperez.org · 12/12/2024
Great discussions at the #AGU24 Notebooks Now! town hall! We still have work to do, but there's a solid foundation and great energy in the community to reimagine scientific publishing. It's not a pipe dream anymore, we have the tools, infrastructure and experience to implement real change.
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Fernando Pérez @fernandoperez.org · 11/12/2024
Personal record at 22,7k thanks to #AGU24 not labeling which of the TWO Westins receptions were at! Thanks #AGU24 for keeping me healthy! ❤️😉
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Fernando Pérez @fernandoperez.org · 09/12/2024
Great job by @row1.ca at the #AGU24 #OpenScience pavillion, discussing @mystmd.org and the future of scientific publishing
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Fernando Pérez @fernandoperez.org · 12/11/2024
Mmh - this URL looks very much like a github fishing attempt to me... Am I missing something? How come the SSL/security info is shown as valid despite being for a different domain? Github doesn't seem to have an official account here, and I'm trying not to post on the other site...
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