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A nice commentary in by @loopdlupien about a newly published article on eastern African paleoclimate change by Baxter & colleagues (link: nature.com/articles/s41586-023) - can simulations of future climatic trends in eastern Africa be reconciled with modern trends?

Past climate unravels the eastern African paradox: nature.com/articles/d41586-023

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My Geococcyx friend stopped by for a quick chat this morning.

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The extent of global sea ice has been consistently setting new daily records for at least the last two months...

More sea ice graphics available at zacklabe.com/global-sea-ice-ex

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The features in Coldwater Cave are just stunning. It's like a cave geology textbook down there.

The cave itself is flooded, with cold water actively flowing through it (Coldwater Cave, amirite?). Even in summer it was pretty cold.

On the ceiling, you could see really neat joint patterns and how fluids exploited those joints, flowed through, and then deposited calcite as they hit the cave and CO2 was released, changing equilibrium and causing chemical precipitation.

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Very proud of our -funded students at the Dept of Geosciences, University of Arizona — our program called “Clouds 2 Core” (C2C) is only for students enrolled in 2-Yr Community and Tribal Colleges and the current cohort of 11 students are from colleges and towns all over (and and ). Today is their final presentations after 8 weeks of research work, here in . Some photos below!

Here’s a couple of of some type of (presumably ?) in our backyard making a out of a !

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Timery 1.5.6 is available and should fix a possible issue with projects in saved timers on the iOS 17 and macOS Sonoma betas.

apps.apple.com/us/app/id142536

Stay tuned for lots of new goodies coming later this year!

Happy time tracking!

@DrEvanGowan I think Crack The Skye was technically the best amongst those, but Leviathan is a personal favorite; v unique when it came out.

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So, the #BBC got here. And they're hosting their own server it seems...

social.bbc/about

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@kau I’ve never experienced worse editorial handling than at Nature brand journals - we had a paper at Nat Comms (which did eventually come out there) where the editor rejected it after multiple rounds of review because one of the reviewers (who we’d already flagged as problematic) sent in a review for a completely different manuscript and the editor didn’t realise and rejected it. They then proceeded to ignore all of our emails until we got their senior editor involved. Crazy

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I spent SO MANY HOURS in grad school manually adjusting peak baselines and deciding what should or shouldn't count as a peak and then going back and doing it all again because I called it a peak in one sample but not the other. I'm SO happy that progress is being made on this problem and very excited to read this preprint!

biorxiv.org/content/10.1101/20

#GCMS #LCMS #XCMS #AnalyticalChemistry #Chromatography
#Metabolomics

Picky with peakpicking: assessing chromatographic peak quality with simple metrics in metabolomics

Chromatographic peakpicking continues to represent a significant bottleneck in automated LC-MS workflows. Uncontrolled false discovery rates and the lack of manually-calibrated quality metrics require researchers to visually evaluate individual peaks, requiring large amounts of time and breaking replicability. This problem is exacerbated in noisy environmental datasets and for novel separation methods such as hydrophilic interaction columns in metabolomics, creating a demand for a simple, intuitive, and robust metric of peak quality. Here, we manually labeled four HILIC oceanographic particulate metabolite datasets to assess the performance of individual peak quality metrics. We used these datasets to construct a predictive model calibrated to the likelihood that visual inspection by an MS expert would include a given mass feature in the downstream analysis. We implemented two novel peak quality metrics, a custom signal-to-noise metric and a test of similarity to a bell curve, both calculated from the raw data in the extracted ion chromatogram and found that these outperformed existing measurements of peak quality. A simple logistic regression model built on two metrics reduced the fraction of false positives in the analysis from 70-80% down to 1-5% and showed minimal overfitting when applied to novel datasets. We then explored the implications of this quality thresholding on the conclusions obtained by the downstream analysis and found that while only 10% of the variance in the dataset could be explained by depth in the default output from the peakpicker, approximately 40% of the variance was explained when restricted to high-quality peaks alone. We conclude that the poor performance of peakpicking algorithms significantly reduces the power of both univariate and multivariate statistical analyses to detect environmental differences. We demonstrate that simple models built on intuitive metrics and derived from the raw data are more robust and can outperform more complex models when applied to new data. Finally, we show that in properly curated datasets, depth is a major driver of variability in the marine microbial metabolome and identify several interesting metabolite trends for future investigation. ### Competing Interest Statement The authors have declared no competing interest.

www.biorxiv.org
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@cobalt Hope you all get rain up there soon! This storm was crazy though…!

Here’s a video of the intense + in central that occurred just now. Wow!

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