The structural stability and compression behavior of hydrated magnesium carbonates are critical for understanding their role in permanent CO2 sequestration and for optimizing low-carbon cementitious materials. This work investigates the compressibility, anisotropy, and structural evolution of Mg5(CO3)4(OH)2·4H2O hydromagnesite mineral under high-pressure conditions using a combination of single-crystal and powder X-ray diffraction, high-pressure Raman spectroscopy, and density functional theory calculations. The results reveal a previously unreported pressure-induced order–disorder–order phase-transition sequence occurring at 0.6(1) and 7.7(1) GPa, driven by positional disorder of a carbonate group along the direction of maximum compressibility. No changes in structural topology or space-group symmetry are observed throughout compression. Quantitative Euler-angle analysis demonstrates that the structural evolution is governed by progressive carbonate tilting and rigid-body rotations of [MgO6] octahedra. A third-order Birch–Murnaghan equation of state yields V0 = 687.71(14) Å3, K0 = 40.7(6) GPa, and K′0 = 5.18(14). Raman spectroscopy confirms the vibrational stability of hydromagnesite over the investigated pressure range and reveals an initial stiffening of OH stretching vibrations, followed by progressive strengthening of hydrogen bonding above ~7.2 GPa. These findings provide a comprehensive crystallographic, elastic, and spectroscopic description of hydromagnesite under compression and offer new insights into the behavior of hydrated magnesium carbonates relevant to carbon storage, geochemical processes, and MgO-based cement technologies.
The Haruchas Dual Complex in southern Namibia is part of the Richtersveld Suite and formed by two stocks that comprise coexisting silica-oversaturated alkaline granite and silica-undersaturated foid syenite, respectively. This contribution integrates mapping, petrography, whole-rock and mineral geochemistry, and U-Pb geochronology to constrain the magmatic evolution, crustal assimilation, and post-magmatic alteration of the complex. Three magmatic stages are distinguished: (1) emplacement of the main intrusive bodies between 914 and 891 Ma; (2) intrusion of a second magma pulse with similar magma composition at 866 Ma; and (3) the intrusion of a dike suite at similar to 815 Ma. These intrusion ages confirm the Haruchas Dual Complex as the northernmost and oldest intrusion of the Richtersveld Suite and the coeval emplacement of the two stocks. Geochemical data indicate that the parental magmas were mantle-derived and generated in a within-plate extensional setting, evolving through variable degrees of fractional crystallization and crustal contamination. The southern stock, dominated by leucogranite, records stronger crustal assimilation, whereas the northern stock, composed of varieties of foid syenite, and tawite, exhibits minor contamination, reflecting spatial and temporal heterogeneity in magma evolution. Post-magmatic alteration overprinted the central portion of the northern stock in two stages: an earlier autometasomatic stage related to Na-rich orthomagmatic fluids and characterized by aegirine growth, followed by a later hydrothermal stage associated with trachyte dike emplacement and characterized by replacement of feldspathoids by natrolite and cancrinite. Combined, geochronological and geochemical data indicate a southward migration of the magmatic center within the Richtersveld Suite during early Rodinia-related crustal thinning.
This paper studies how wages and productivity among publicly listed firms vary with AI attention during a period of uneven AI adoption. AI attention measures the prominence of AI in the country-level information environment. It is distinct from AI adoption. The wage measure captures average staff expenditure on wages and salaries per employee. Using data for 69,783 listed firms in 83 countries over 2004-2023, I measure this attention with Google Trends and combine TWFE, IV-2SLS, and local projections to estimate static and dynamic relationships. Among listed firms in advanced economies (AEs), higher AI attention is associated with lower wages but higher labour productivity and TFP. Listed firms in emerging market and developing economies (EMDEs) show short-run wage gains and positive productivity responses. These patterns also vary across firms, with wage declines more pronounced among smaller, lower-productivity, and goods-producing listed firms. The sample represents the organised listed corporate sector, which constitutes a particularly selective segment of the firm population in EMDEs; the wider SME, informal, and unlisted sectors remain outside the scope of the analysis. The patterns are consistent with expectations, perceived substitution risk, organisational investment, and workforce composition playing different roles in listed-firm adjustment.
Despite the availability of potent antifungal compounds, invasive fungal diseases (IFD) are still a major cause for morbidity and mortality in immunocompromised pediatric and adult patients, and risk and outcome of IFDs are determined by the degree of the suppression of the specific arms of the immune system. This prompted us to review the current knowledge of immunotherapeutic antifungal approaches. We critically review important in vitro and animal data as well as clinical studies of immunotherapy for IFD, in particular granulocyte transfusion, the adoptive transfer of primary and genetically modified Natural Killer cells and fungal-specific T cells, and the use of colony-stimulating factors and cytokines. Although promising data of in vitro and animal models have been reported for many strategies, no clear benefit has been demonstrated in the clinical setting to date.
This paper provides a review of Late-Paleozoic skarns in the Erzgebirge/Krusne hory region (Germany/Czech Republic) with a particular emphasis on the Aue-Schwarzenberg and Geyer-Ehrenfriedersdorf Districts that host the most prolific skarn systems. Most skarns in the Erzgebirge replace carbonate units that occur intercalated with metamorphosed sedimentary and volcano-sedimentary host rock successions of pre-Variscan age. Skarn compositions range from calcic to magnesian, depending on the protolith. The timing of skarn formation is constrained by U-Pb ages of garnet and cassiterite, ranging from similar to 340 to similar to 295 Ma, broadly coinciding with different episodes of late- to post-Variscan magmatism. Textural and geochronological data implies that many of the skarns are multi-generational, with hiatuses between individual stages of up to 5 -10 Ma, indicating that they are the product of several magmatic-hydrothermal events. Early skarns are commonly characterized by skarnoid textures typical for heat-dominated metasomatism (rock-buffered), whereas younger skarns mainly show metasomatic textures and open space-infill typical for fluid-dominated metasomatism (fluid-buffered). We postulate that the relationship between timing and texture is related to uplift and exhumation of the Erzgebirge following the collisional phase of the Variscan orogeny. Most of the Sn mineralization is hosted in cassiterite, commonly intergrown with retrograde actinolite and chlorite. However, a significant portion of Sn remains locked within prograde calc-silicate phases (e.g., malayaite, Sn-bearing garnet), rendering it inaccessible for economic extraction. Indium mineralization is mainly hosted by sphalerite and less importantly other sulfides that are also associated with the retrograde stage. Scheelite is the main host of W, which shows a preferred affiliation to calcic skarns and occurs during the pro- and retrograde stage.
