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1. Spin Dynamics and Phonons in Chromites CoCr ₂ O ₄ and MnCr ₂ O ₄

   https://doi.org/10.1088/0256-307X/41/11/117503  

   Xu_徐, Wei 威; Lin_林, Gaoting 高庭; Shu_舒, Mingfang 明方; Jiao_焦, Jinlong 金龙; Zhu_朱, Jinfeng 金峰; Ren_任, Qingyong 清勇; Le, Manh Duc; Luo_罗, Xuan 轩; Sun_孙, Yuping 玉平; Liu_刘, Yi 毅; et al (November 2024, Chinese Physics Letters)

   Abstract Spinel compounds are of great interest in both fundamental and application-oriented perspectives due to the geometric magnetic frustration inherent to their lattice and the resulting complex magnetic states. Here, we applied x-ray diffraction, magnetization, heat capacity and powder inelastic neutron scattering measurements, along with theoretical calculations, to study the exotic properties of chromite-spinel oxides CoCr₂O₄and MnCr₂O₄. The temperature dependence of the phonon spectra provides an insight into the correlation between oxygen motion and the magnetic order, as well as the magnetoelectric effect in the ground state of MnCr₂O₄. Moreover, spin-wave excitations in CoCr₂O₄and MnCr₂O₄are compared with Heisenberg model calculations. This approach enables the precise determination of exchange energies and offers a comprehensive understanding of the spin dynamics and relevant exchange interactions in complicated spiral spin ordering. 

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2. Effects of year‐long exposure to elevated pCO₂ on the metabolism of back reef and fore reef communities

   https://doi.org/10.1002/lno.12504  

   Edmunds, Peter J; Doo, Steve S; Carpenter, Robert C (March 2024, Limnology and Oceanography)

   Abstract The implications of ocean acidification are acute for calcifying organisms, notably tropical reef corals, for which accretion generally is depressed and dissolution enhanced at reduced seawater pH. We describe year‐long experiments in which back reef and fore reef (17‐m depth) communities from Moorea, French Polynesia, were incubated outdoors under pCO₂regimes reflecting endpoints of representative concentration pathways (RCPs) expected by the end the century. Incubations were completed in three to four flumes (5.0 × 0.3 m, 500 L) in which seawater was refreshed and circulated at 0.1 m s⁻¹, and the response of the communities was evaluated monthly by measurements of net community calcification (NCC) and net community productivity (NCP). For both communities, NCC (but not NCP) was affected by treatments and time, with NCC declining with increasing pCO₂, and for the fore reef, becoming negative (i.e., dissolution was occurring) at the highest pCO₂(1067–1433μatm, RCP8.5). There was scant evidence of community adjustment to reduce the negative effects of ocean acidification, and inhibition of NCC intensified in the back reef as the abundance of massivePoritesspp. declined. These results highlight the risks of dissolution under ocean acidification for coral reefs and suggest these effects will be most acute in fore reef habitats. Without signs of amelioration of the negative effects of ocean acidification during year‐long experiments, it is reasonable to expect that the future of coral reefs in acidic seas can be predicted from their current known susceptibility to ocean acidification. 

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3. Calculating surface ocean pCO ₂ from biogeochemical Argo floats equipped with pH: An uncertainty analysis: Calculating Ocean pCO ₂ From Float pH

   https://doi.org/10.1002/2016GB005541  

   Williams, N. L.; Juranek, L. W.; Feely, R. A.; Johnson, K. S.; Sarmiento, J. L.; Talley, L. D.; Dickson, A. G.; Gray, A. R.; Wanninkhof, R.; Russell, J. L.; et al (March 2017, Global Biogeochemical Cycles)
4. Equatorial Pacific pCO ₂ Interannual Variability in CMIP6 Models

   https://doi.org/10.1029/2022JG007243  

   Wong, Suki C.; McKinley, Galen A.; Seager, Richard (December 2022, Journal of Geophysical Research: Biogeosciences)
5. Physical and Biological Controls of the Drake Passage pCO ₂ Variability

   https://doi.org/10.1029/2020GB006644  

   Jersild, Annika; Ito, Takamitsu (September 2020, Global Biogeochemical Cycles)

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