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1. Quantifying Soil Phosphorus Dynamics: A Data Assimilation Approach

   https://doi.org/10.1029/2018JG004903  

   Hou, Enqing; Lu, Xingjie; Jiang, Lifen; Wen, Dazhi; Luo, Yiqi (July 2019, Journal of Geophysical Research: Biogeosciences)

   Abstract The dynamics of soil phosphorus (P) control its bioavailability. Yet it remains a challenge to quantify soil P dynamics. Here we developed a soil P dynamics (SPD) model. We then assimilated eight data sets of 426‐day changes in Hedley P fractions into the SPD model, to quantify the dynamics of six major P pools in eight soil samples that are representative of a wide type of soils. The performance of our SPD model was better for labile P, secondary mineral P, and occluded P than for nonoccluded organic P (Po) and primary mineral P. All parameters describing soil P dynamics were approximately constrained by the data sets. The average turnover rates were labile P 0.040 g g⁻¹day⁻¹, nonoccluded Po 0.051 g g⁻¹day⁻¹, secondary mineral P 0.023 g g⁻¹day⁻¹, primary mineral P 0.00088 g g⁻¹day⁻¹, occluded Po 0.0066 g g⁻¹day⁻¹, and occluded inorganic P 0.0065 g g⁻¹day⁻¹, in the greenhouse environment studied. Labile P was transferred on average more to nonoccluded Po (transfer coefficient of 0.42) and secondary mineral P (0.38) than to plants (0.20). Soil pH and organic C concentration were the key soil properties regulating the competition for P between plants and soil secondary minerals. The turnover rate of labile P was positively correlated with that of nonoccluded Po and secondary mineral P. The pool size of labile P was most sensitive to its turnover rate. Overall, we suggest data assimilation can contribute significantly to an improved understanding of soil P dynamics. 

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2. Cationic Bis(Gold) Indenyl Complexes

   https://doi.org/10.1002/cplu.202300691  

   Slinger, Brady_L; Zhu, Jiaqi; Widenhoefer, Ross_A (February 2024, ChemPlusChem)

   Abstract Reaction of (P)AuOTf [P=P(t‐Bu)₂o‐biphenyl] with indenyl‐ or 3‐methylindenyl lithium led to isolation of gold η¹‐indenyl complexes (P)Au(η¹‐inden‐1‐yl) (1 a) and (P)Au(η¹‐3‐methylinden‐1‐yl) (1 b), respectively, in >65 % yield. Whereas complex1 bis static, complex1 aundergoes facile, degenerate 1,3‐migration of gold about the indenyl ligand (ΔG^≠_153K=9.1±1.1 kcal/mol). Treatment of complexes1 aand1 bwith (P)AuNTf₂led to formation of the corresponding cationic bis(gold) indenyl complexestrans‐[(P)Au]₂(η¹,η¹‐inden‐1,3‐yl) (2 a) andtrans‐[(P)Au]₂(η¹,η²‐3‐methylinden‐1‐yl) (2 b), respectively, which were characterized spectroscopically and modeled computationally. Despite the absence of aurophilic stabilization in complexes2 aand2 b, the binding affinity of mono(gold) complex1 atoward exogenous (P)Au⁺exceed that of free indene by ~350‐fold and similarly the binding affinity of1 btoward exogenous (P)Au⁺exceed that of 3‐methylindene by ~50‐fold. The energy barrier for protodeauration of bis(gold) indenyl complex2 awith HOAc was ≥8 kcal/mol higher than for protodeauration of mono(gold) complex1 a. 

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3. Laser-cooling Cadmium Bosons and Fermions with Near Ultraviolet Triplet Excitations

   https://doi.org/10.1088/1742-6596/2889/1/012006  

   Gibble, Kurt (November 2024, Journal of Physics: Conference Series)

   Abstract Cadmium is laser-cooled and trapped with excitations to triplet states with UVA light, first using only the 67 kHz wide 326 nm intercombination line and subsequently, for large loading rates, the 25 MHz wide 361 nm³P₂→³D₃transition. Eschewing the hard UV 229 nm¹S₀→¹P₁transition, only small magnetic fields gradients, less than 6 G cm⁻¹, are required enabling a 100% transfer of atoms from the 361 nm trap to the 326 nm narrow-line trap. All 8 stable cadmium isotopes are straightforwardly trapped, including two nuclear-spin- $\frac{1}{2}$fermions that require no additional repumping. We observe evidence of³P₂collisions limiting the number of trapped metastable atoms, report isotope shifts for¹¹¹Cd and¹¹³Cd of the 326 nm¹S₀→³P₁, 480nm³P₁→³S₁, and 361 nm³P₂→³D₃transitions, and measure the¹¹⁴Cd 5s5p³P₂→ 5s5d³D₃transition frequency to be 830 096 573(15) MHz. 

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4. Atomic Transition Probabilities for Transitions of Si i and Si ii and the Silicon Abundances of Several Very Metal-poor Stars ^∗  

   https://doi.org/10.3847/1538-4365/acb642  

   Den Hartog, E. A.; Lawler, J. E.; Sneden, C.; Roederer, I. U.; Cowan, J. J. (March 2023, The Astrophysical Journal Supplement Series)

   Abstract We report new measurements of branching fractions for 20 UV and blue lines in the spectrum of neutral silicon (Sii) originating in the 3s²3p4s³P^o_1,2,¹P^o₁, and 3s3p³¹D^o_1,2upper levels. Transitions studied include both strong, nearly pure LS multiplets as well as very weak spin-forbidden transitions connected to these upper levels. We also report a new branching fraction measurement of the⁴P_1/2–²P^o_1/2,3/2intercombination lines in the spectrum of singly ionized silicon (Siii). The weak spin-forbidden lines of Siiand Siiiprovide a stringent test on recent theoretical calculations, to which we make comparison. The branching fractions from this study are combined with previously reported radiative lifetimes to yield transition probabilities and log(gf) values for these lines. We apply these new measurements to abundance determinations in five metal-poor stars. 

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5. Coupled, decoupled, and abrupt responses of vegetation to climate across timescales

   https://doi.org/10.1126/science.adr6700  

   Fastovich, David; Meyers, Stephen R; Saupe, Erin E; Williams, John W; Dornelas, Maria; Dowding, Elizabeth M; Finnegan, Seth; Huang, Huai-Hsuan M; Jonkers, Lukas; Kiessling, Wolfgang; et al (July 2025, Science)

   Climate and ecosystem dynamics vary across timescales, but research into climate-driven vegetation dynamics usually focuses on singular timescales. We developed a spectral analysis–based approach that provides detailed estimates of the timescales at which vegetation tracks climate change, from 10¹to 10⁵years. We report dynamic similarity of vegetation and climate even at centennial frequencies (149⁻¹to 18,012⁻¹year⁻¹, that is, one cycle per 149 to 18,012 years). A breakpoint in vegetation turnover (797⁻¹year⁻¹) matches a breakpoint between stochastic and autocorrelated climate processes, suggesting that ecological dynamics are governed by climate across these frequencies. Heightened vegetation turnover at millennial frequencies (4650⁻¹year⁻¹) highlights the risk of abrupt responses to climate change, whereas vegetation-climate decoupling at frequencies >149⁻¹year⁻¹may indicate long-lasting consequences of anthropogenic climate change for ecosystem function and biodiversity. 

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