Erik van Nimwegen
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erikvannimwegen.bsky.social
Erik van Nimwegen
@erikvannimwegen.bsky.social
Gene regulatory networks and genome evolution. How do single cells make up their minds?
@[email protected]
@NimwegenLab on twitter. Sorry X.
Perhaps you didn't ask yourself because it is a pointless question. To LLMs that are being trained, all text on the internet is data. To astronomers the static on your radio is data. Who needs a definition? Seems like an empty 'philosopher problem' to me.
November 22, 2025 at 11:48 AM
Nutriënten? Ik weet niet hoor. Ik woon al 30 jaar niet meer in Nederland. Maar ik dacht dat voedselstoffen heetten in het Nederlands.
November 18, 2025 at 6:58 PM
Current write ups are all bland tasteless off-white colored talk-a-lot-without-saying-anything. Nothing to object to and zero character.
Yes for sure there was signal. We have stats on how initial assessments line up with final decisions after extensive in-person presentation + interviews.
November 14, 2025 at 8:58 PM
No, I am not wrong. You are attacking a straw man. Of course using AI to write a letter relies on technical progress. But you were implying that avoiding the use of AI for writing application letters would amount to stopping technological progress, which is frankly absurd.
November 14, 2025 at 1:12 PM
You’ll come to believe it eventually.
November 7, 2025 at 6:31 PM
Yes. It's all downhill from here. I know. I'm talking from experience.
November 7, 2025 at 4:36 PM
Please let us know what you think. And much agreed on Bach and Vermeer (maybe I should give Proust another try).
September 29, 2025 at 1:35 PM
and includes accurate error-bars on all estimates.

We believe RealTrace can dramatically enhance the power of time-lapse microscopy data by allowing identification and quantification of far more subtle features in the dynamics than is possible with simple data smoothing approaches. n/n
September 17, 2025 at 2:19 PM
Surprisingly, protein production rates adapt to their new steady-states far more quickly and with only a minimal transient.

RealTrace can be applied to essentially any time-lapse fluorescence microscopy data and gives accurate estimates of instantaneous growth and volumic GFP production rates, 10/n
September 17, 2025 at 2:19 PM
Finally, upon a sudden `downshift' in nutrients, we see very reproducible time-dependent responses across single cells. All cells go almost into growth arrest, then overshoot in growth rate, only to relax to a final growth rate over a time scale of 3 cell cycles. 9/n
September 17, 2025 at 2:19 PM
minimum early in the cell cycle and a maximum late in the cell cycle. In contrast, protein production rates show more complex patterns that vary across conditions and across promoters, even across constitutive promoters!
As far as we are aware, no current models can explain these patterns. 8/n
September 17, 2025 at 2:19 PM
time, and in slower growth conditions, both the amplitude and duration of these fluctuations increases.

Second, both growth rate and volumic protein production vary systematically across the cell cycle. Interestingly, the variation in growth rate is the same in all conditions, with a 7/n
September 17, 2025 at 2:19 PM
We use data from E. coli cells carrying fluorescent reporters of constitutive and ribosomal genes, growing in a microfluidic device in different conditions, to highlight the kind of subtle patterns RealTrace can uncover.
First, instantaneous growth rates vary substantially across cells and 6/n
September 17, 2025 at 2:19 PM
RealTrace is very generally applicable, which we demonstrate by applications to data from E. coli cells, mouse embryonic stem cell nuclei (data from the lab of @davidsuter.bsky.social), and entire C. elegans larvae (data from the lab of @betowbin.bsky.social). 5/n
September 17, 2025 at 2:19 PM
are correlated on short time scales, all measurement errors are independent. We implemented this idea into a rigorous Bayesian procedure that uses maximum entropy process priors and recursively approximates the non-linear dynamics over short time intervals. 4/n
September 17, 2025 at 2:19 PM
We can't fit the data to particular curves because we typically don't know what form the dynamics will take, and local smoothing systematically distorts the true dynamics by replacing it with a time average.

RealTrace solves this challenge using only one assumption: while biological changes 3/n
September 17, 2025 at 2:19 PM
Tracking the behavior of single cells using fluorescence time-lapse microscopy is becoming increasingly popular but there is a fundamental challenge in analyzing such data: as biological changes are small on short time scales, much of the true dynamics is hidden under measurement noise. 2/n
September 17, 2025 at 2:19 PM