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Aboveground and belowground carbon and nitrogen utilization in three drought-exposed subtropical tree species after rewetting
Item type: Journal Article
Feng M.; Ouyang S.; Tie L.; et al. (2026)
Drought frequency and intensity increasingly threaten tree survival and growth by altering trees carbon (C), nitrogen (N) and water utilization. Yet, the interplay of aboveground and belowground processes during drought recovery remains unclear. We conducted a microcosm experiment with pine (Pinus massoniana Lamb.), fir (Cunninghamia lanceolata (Lamb.) Hook.) and oak (Quercus acutissima Carruth.) saplings, exposing them to three levels of drought intensity (i.e. well-watered, moderate drought and severe drought) for 3 months, followed by 30 days of rewetting. Using 13C and 15N isotopes, we tracked C and N allocation. Our results showed that drought-stressed saplings rapidly increased net photosynthesis and predawn leaf water potential after rewetting, with the exception of severely drought-exposed oak. Root N uptake (represented by 15N recovery) also recovered quickly, even surpassing well-watered levels in moderately drought-exposed pine and fir. However, severe drought-stressed pine and fir exhibited significantly lower coarse root non-structural carbohydrates (NSC), while oak maintained higher root and stem NSC. The two coniferous species, previously severely drought-stressed, prioritized C and N allocation to aboveground and had reduced xylem hydraulic conductance after rewetting. The recovery rate of oak was slower, with limited N translocation to aboveground tissues due to leaf abscission. In conclusion, rapid root recovery coupled with more recently photosynthetic C retained in aboveground organ led to root NSC consumption in drought-stressed pine and fir. Conversely, oak’s recovery was slower, largely driven by its phenology. This study underscores that aboveground and belowground C and N allocation patterns are closely linked during drought recovery, determined by species-specific traits and the severity of prior drought stress.
Nucleation Instability Preempts Relativistic Domain Wall Transport in High-Exchange Ferrimagnetic Nanowires
Item type: Journal Article
Diona P. (2026)
Current-driven domain wall motion in ferrimagnets can approach the spin-wave velocity, giving rise to relativistic-like dynamics. While this regime has been experimentally observed in crystalline ferrimagnetic garnets and amorphous GdFeCo, the material conditions that determine whether it can be accessed remain unresolved. Here, we investigate spin-orbit-torque-driven domain wall motion in high-exchange GdCo nanowires using magneto-optical Kerr effect microscopy. We find that nucleation preempts relativistic transport. In GdCo, neither velocity saturation nor high-field collapse is observed. Instead, the large exchange interaction raises the maximum spin-wave group velocity to (Formula presented.), far above the experimentally accessible domain wall velocities. Before this limit can be approached, increasing current density and in-plane magnetic field induce domain nucleation, disrupting steady-state propagation. We map the boundary separating domain wall transport from nucleation instability and show that the nucleation threshold decreases with pulse duration, consistent with thermally assisted barrier crossing. These results identify nucleation as the mechanism that prevents access to the relativistic regime in high-exchange ferrimagnets and establish a dynamical phase boundary between steady propagation and nucleation.
Mixed Magnetocrystalline Anisotropy and the Magnetization of Monoclinic 4C Pyrrhotite
Item type: Journal Article
Gehring A.U.; Weidler P.G.; Koulialias D.; et al. (2026)
Ferrimagnetic, monoclinic 4C pyrrhotite (Fe7S8), as the iron deficient endmember of the pyrrhotite solid-solution series (Fe1–xS, 0 < x ≤ 0.125), is the main sulfide mineral widely used in rock and paleomagnetic studies of Earth's crust and extraterrestrial materials. Its particular magnetocrystalline anisotropy (MCA), characterized by an easy plane and extreme hard c-axis, originates from ordered vacancies and Fe cations in octahedral sites of a hexagonal close packing of sulfur. Here, we combine a detailed crystallographic analysis together with magnetization and magnetic torque data of a natural 4C pyrrhotite to demonstrate the configurational effect of occupied and vacant Fe-sites on the MCA. The crystallographic analysis reveals two sub-systems with six-fold symmetry set off by 30° that mainly arise from the vacancy ordering. The Fe cations in the two sub-systems have the same spin-orbit coupling as inferred from the out-of-plane spin rotations, but they differ in their dipolar coupling. The interplay of these coupling mechanisms generates a mixed MCA with respect to the two crystallographic sub-systems. Such anisotropy has a critical effect on the magnetization properties and becomes evident by the occurrence of 12-fold magnetic torques. The intrinsic directional magnetization behavior and the characteristic low-temperature magnetic anomaly known as the Besnus transition of 4C pyrrhotite can be derived from the crystallographic structure on the atomic scale that governs the MCA. This finding underscores the relevance of vacancy order on the magnetization of 4C pyrrhotite and its fidelity as a key magnetic mineral in geoscience and cosmology.
Broad-Spectrum, Cell Envelope-Active Marinocyclin Antibiotics From a Coral-Derived Bacterium Are Effective Against Colistin-Resistant Bacteria
Item type: Journal Article
Chepkirui C.; Silva S.; Straetener J.; et al. (2026)
The marine bacterial genus Aquimarina comprises diverse members with numerous natural product biosynthetic gene clusters but few characterized compounds. Here we report a novel class of lipopeptides with exceptional antibiotic activity, named marinocyclins, isolated from Aquimarina megaterium EL43 associated with the octocoral Eunicella labiata. The major congener marinocyclin A exhibited potent and uniform activity against a broad panel of drug-resistant gram-negative and gram-positive pathogens, including ESKAPE bacteria. The natural product efficiently compromised the outer and inner bacterial membranes, leading to rapid cell permeabilization and lysis. This activity profile was mediated by the ability to bind lipopolysaccharides, anionic phospholipids enriched in bacterial membranes, and peptidoglycan precursors. Eukaryotic cytotoxicity required higher doses than antibacterial activity. Genomic data suggest a nonribosomal biosynthetic origin for marinocyclins. These findings position marinocyclins as a promising new scaffold for antibiotic development and highlight the potential of Aquimarina spp. as a source of novel antibiotics. Further medicinal chemistry optimization of marinocyclins could enhance their prokaryotic selectivity to generate leads for treating infections caused by drug-resistant pathogens.
The welfare effects of explicit and implicit subsidies on fossil fuels
Item type: Journal Article
Kalmey T.; Rausch S.; Schneider J. (2026)
We study the welfare effects of removing explicit and implicit fossil fuel subsidies, the latter via corrective pricing of local air pollution. We map a multi-region general-equilibrium model with global supply chains to granular data on subsidies, marginal external costs, and national income and product accounts. On average, unilateral subsidy removal raises a country’s welfare by 3.2%, generates revenues equal to 3.1% of consumption, and lowers the carbon price needed for Paris targets by 46%. Non-market gains exceed market losses in most countries. Local air pollution pricing drives 97% of net benefits; removing explicit subsidies alone has minor effects on welfare and emissions. A quarter of countries would already reach their Paris climate target, making additional carbon pricing redundant. Combining subsidy removal with carbon pricing dominates carbon pricing alone everywhere. Global multilateral subsidy removal cuts emissions by 27.4% and raises global welfare, excluding climate benefits, by 2.3%. Corrective fossil fuel taxation can align economic, fiscal, and climate goals. (JEL C68, H23, Q43, Q58)