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   https://doi.org/10.1016/j.pmatsci.2021.100891  

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2. THROUGH FIRE, AND THROUGH WATER, AN ABUNDANCE OF MID-DEVONIAN CHARCOAL

   https://doi.org/10.2110/palo.2024.009  

   GLASSPOOL, IAN J; GASTALDO, ROBERT A (September 2024, Palaios)

   Abstract Evidence of fire in the Middle Devonian remains globally scarce. Charcoalified mesofossils recovered from the Emsian–Eifelian Trout Valley and St. Froid Lake formations of Maine are direct evidence of wildfires proximal to the Acadian Orogen, formed as the Avalon terrane and the North American plate collided. These mesofossils include charred psilophytes, lycopsids, prototaxodioids, enigmatic taxa such as Spongiophyton, and coprolites. Here, fire combusted a senesced and partially decayed litter, and the intimately associated nematophytes, following a period of extended dryness. We envisage wildfires occurred during neap tide when exposure of the flora of this estuarine setting was prolonged. Herein we provide a reconstruction of this Middle Devonian landscape and its flora in which lightning generated by post-dry season storms ignited wildfires that propagated through an extensive psilophyte-dominated litter. 

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3. Through-bond and through-space radiofrequency amplification by stimulated emission of radiation

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   Trofimov, Ivan_A; Salnikov, Oleg_G; Pravdivtsev, Andrey_N; de_Maissin, Henri; Yi, Anna_P; Chekmenev, Eduard_Y; Hövener, Jan-Bernd; Schmidt, Andreas_B; Koptyug, Igor_V (October 2024, Communications Chemistry)

   Abstract Radio Amplification by Stimulated Emission of Radiation (RASER) is a phenomenon observed during nuclear magnetic resonance (NMR) experiments with strongly negatively polarized systems. This phenomenon may be utilized for the production of very narrow NMR lines, background-free NMR spectroscopy, and excitation-free sensing of chemical transformations. Recently, novel methods of producing RASER by ParaHydrogen-Induced Polarization (PHIP) were introduced. Here, we show that pairwise addition of parahydrogen to various propargylic compounds induces RASER activity of other protons beyond those chemically introduced in the reaction. In high-field PHIP, negative polarization initiating RASER is transferred via intramolecular cross-relaxation. When parahydrogen is added in Earth’s field followed by adiabatic transfer to a high field, RASER activity of other protons is induced via bothJ-couplings and cross-relaxation. This through-bond and through-space induction of RASER holds potential for the ongoing development and expansion of RASER applications and can potentially enhance spectral resolution in two-dimensional NMR spectroscopy techniques. 

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4. Fairness through Aleatoric Uncertainty

   https://doi.org/10.1145/3583780.3614875  

   Tahir, Anique; Cheng, Lu; Liu, Huan (October 2023, ACM)

   We propose a simple yet effective solution to tackle the often-competing goals of fairness and utility in classification tasks. While fairness ensures that the model's predictions are unbiased and do not discriminate against any particular group or individual, utility focuses on maximizing the model's predictive performance. This work introduces the idea of leveraging aleatoric uncertainty (e.g., data ambiguity) to improve the fairness-utility trade-off. Our central hypothesis is that aleatoric uncertainty is a key factor for algorithmic fairness and samples with low aleatoric uncertainty are modeled more accurately and fairly than those with high aleatoric uncertainty. We then propose a principled model to improve fairness when aleatoric uncertainty is high and improve utility elsewhere. Our approach first intervenes in the data distribution to better decouple aleatoric uncertainty and epistemic uncertainty. It then introduces a fairness-utility bi-objective loss defined based on the estimated aleatoric uncertainty. Our approach is theoretically guaranteed to improve the fairness-utility trade-off. Experimental results on both tabular and image datasets show that the proposed approach outperforms state-of-the-art methods w.r.t. the fairness-utility trade-off and w.r.t. both group and individual fairness metrics. This work presents a fresh perspective on the trade-off between utility and algorithmic fairness and opens a key avenue for the potential of using prediction uncertainty in fair machine learning. 

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5. Electron hopping through proteins

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   Warren, Jeffrey J.; Ener, Maraia E.; Vlček, Antonín; Winkler, Jay R.; Gray, Harry B. (November 2012, Coordination Chemistry Reviews)