ALBERT

Description: Opinion formation within society follows complex dynamics. Towards its understanding, axiomatic theory can complement data analysis. To this end we propose an axiomatic model of opinion formation that aims to capture the interaction of individual conviction with social influence in a minimalist fashion. Despite only representing that (1) agents have an initial conviction with respect to a topic and are (2) influenced by their neighbours, the model shows emergence of opinion clusters from an initially unstructured state. Here, we show that increasing individual self-reliance makes agents more likely to align their socially influenced opinion with their inner conviction which concomitantly leads to increased polarisation. The opinion drift observed with increasing self-reliance may be a plausible analogue of polarisation trends in the real world. Modelling the basic traits of striving for individual versus group identity, we find a trade-off between individual fulfilment and societal cohesion. This finding from fundamental assumptions can serve as a building block to explain opinion polarisation.

Description: Renewable hydrogen is necessary for the decarbonization of sectors that are difficult to electrify, such as industry and aviation, and as a storage medium for surplus electricity from renewable sources.

Description: Large igneous provinces (LIP) are vast (0.2 to 〉1 Mkm3) outpourings of basaltic lava and voluminous intrusions of magmas that have had important environmental consequences, in many cases leading to immense greenhouse gas release and mass extinctions. Magmatic oxygen fugacity (fO2) influences the chemistry of volcanic gases and is an important parameter for examining the links between LIP eruptions and environmental change. To constrain the fO2 of LIP magmas, we report olivine elemental chemistry of 399 crystals from a set of fifteen olivine-rich LIP samples, spanning in age from the Proterozoic (∼1270 Ma) to the Miocene (∼17 Ma). Concentrations of V in olivine are used to show that mafic LIP lavas erupted at +1.20 ± 0.95 ΔFMQ, on average more oxidized than mid ocean ridge basalts (MORB) at −0.28 ± 0.28 ΔFMQ. Mafic LIP magmas show a much larger range than MORB, however. Additionally, fO2 shows a negative correlation with parental magma MgO content, with high MgO lavas approaching the MORB range. This correlation is likely due to sampling of a heterogeneous mixture of oxidized and reduced lithologies, as also sampled by ocean island basalts (OIB). Correlation between fO2 and isotopic ratios such as 143Nd/144Nd demonstrates that the oxidized endmember is geochemically enriched, and may result from subduction recycling of oxidized surficial materials. The high fO2 of primitive LIP magmas demonstrate that they largely emitted oxidized gases during eruption, and furthermore, that LIP magmas associated with mass extinctions have similar magmatic fO2 to those that are not. Global plate tectonic position, magnitude and duration of LIP volcanic eruptions and magmatic degassing, as well as interaction with sedimentary basins in the crust - but not mantle source fO2 - are likely to be the critical factors for whether a LIP was associated with a mass extinction.

Description: Analysis and identifying the displacement characteristics play a key role in timely monitoring and detecting the physical responses of the bridge to ensure the safety of the human and structure. Many previous kinds of research used GNSS data to identify displacement and oscillation modelling of the bridge with different algorithms. This study uses GNSS time-series data to determine linear displacement and model oscillation of the bridge using a procedure including filtering outliers, linear regression, and sin function to identify amplitude in three directions, the plane displacement velocity, spatial displacement velocity, and vibration model of the bridge. The data in the research in the GNSS time-series data from three P5 GNSS receivers of the CHC brand on the Dachongyong bridge in Nanning, China with 1646 observations, at one-hour sample intervals in 68 consecutive days. The plane and spatial velocity of the three points DCQ01, DCQ02, and DCQ03 is 0.0181 mm/h, 0.0185 mm/h; 0.0114 mm/h, 0.0173 mm/h; and 0.0071 mm/h, 0.0082 mm/h respectively. The study results are significant in analyzing and identifying the bridge's displacement characteristics.

Description: Double seismic zones (DSZs) are a feature of some subducting slabs, where intermediate-depth earthquakes (~70–300 km) align along two separate planes. The upper seismic plane is generally attributed to dehydration embrittlement, whereas mechanisms forming the lower seismic plane are still debated. Thermal conductivity of slab minerals is expected to control the temperature evolution of subducting slabs, and therefore their seismicity. However, effects of the potential anisotropic thermal conductivity of layered serpentine minerals with crystal preferred orientation on slab’s thermal evolution remain poorly understood. Here we measure the lattice thermal conductivity of antigorite, a hydrous serpentine mineral, along its crystallographic b- and c-axis at relevant high pressure-temperature conditions of subduction. We find that antigorite’s thermal conductivity along the c-axis is ~3–4 folds smaller than the b-axis.Our numericalmodels further reveal thatwhen the lowthermal-conductivity c-axis is aligned normal to the slab dip, antigorite’s strongly anisotropic thermal conductivity enables heating at the top portion of the slab, facilitating dehydration embrittlement that causes the seismicity in the upper plane of DSZs. Potentially, the antigorite’s thermal insulating effect also hinders the dissipation of frictional heat inside shear zones, promoting thermal runaway along serpentinized faults that could trigger intermediatedepth earthquakes.

Description: Tourmaline is common in rare element pegmatites of the Nb-Y-F (NYF) type in the south-central part of the Proterozoic Sveconorwegian orogen in southern Norway. In the global context, however, tourmaline appears rare in this type of pegmatite. This study aims to explain the unusual tourmaline abundance in these pegmatites and the origin of boron (B) in the respective melts, and to raise awareness of tourmaline in NYF pegmatites generally. Tourmalines from six pegmatites in three Sveconorwegian lithotectonic units: Bamble, Kongsberg and Idefjorden, were investigated in terms of their mineral chemistry and δ11B values, in addition to bulk rock analyses of pegmatites and host rocks. Tourmalines in pegmatites from Bamble and Kongsberg record B isotopic compositions (δ11B = -1.0 to + 9.9 ‰) that are heavy relative to continental crust and mantle sources. In contrast, tourmaline in pegmatites and host rocks from Idefjorden have light B isotopic ratios (δ11B = -14.8 to −12.5 ‰) that are typical crustal values. We suggest that the latter melts were sourced from orthogneisses at depth. We relate the heavy B isotopic composition of Bamble and Kongsberg pegmatites to regional Na-metasomatism by fluids sourced from Mesoproterozoic shallow marine sediments. This is supported by previously published δ11B ratios from metasomatized Bamble host rocks. The spatial association of pegmatites with Na-metasomatism in the basement rocks suggests that metasomatism enhanced the fertility and B-concentration in the affected lithologies, favouring partial melting and the formation of tourmaline-bearing pegmatites. These findings contribute to understanding the petrogenesis of Sveconorwegian pegmatites but they also imply that B can play a greater role in the formation of NYF pegmatites than previously thought and that tourmaline has value as a petrogenetic tool in this type of pegmatites as well as in the Li-Cs-Ta (LCT) type to which is it is more commonly applied.

Description: The world should redouble its efforts on the SDGs, not abandon them. Here’s how to progress the United Nations’ agenda towards 2050.

Description: The Arctic sea ice (ASI) is expected to decrease with further global warming. However, considerable uncertainty remains regarding the temperature range that would lead to a completely ice-free Arctic. Here, we combine satellite data and a large suite of models from the latest phase of the Coupled Model Intercomparison Project (CMIP6) to develop an empirical, observation-based projection of the September ASI area for increasing global mean surface temperature (GMST) values. This projection harnesses two simple linear relationships that are statistically supported by both observations and model data. First, we show that the September ASI area is linearly proportional to the area inside a specific northern hemisphere January–September mean temperature contour Tc. Second, we use observational data to show how zonally averaged temperatures have followed a positive linear trend relative to the GMST, consistent with Arctic amplification. To ensure the reliability of these observations throughout the rest of the century, we validate this trend by employing the CMIP6 ensemble. Combining these two linear relationships, we show that the September ASI area decrease will accelerate with respect to the GMST increase. Our analysis of observations and CMIP6 model data suggests a complete loss of the September ASI (area below 10〈sup〉8〈/sup〉 km〈sup〉2〈/sup〉) for global warming between 1.5 C and 2.2 C above pre-industrial GMST levels.

Description: The loss of Arctic sea ice (ASI) represents a major transformation in the Arctic region, impacting regional and global climate, ecosystems, and socio-economic structures. Observational and reanalysis data have consistently shown a notable shift in polar environmental conditions over recent decades, marked by a substantial reduction in the ASI area and a rise in the variability in its coverage and distribution. Utilizing data from the latest Coupled Model Intercomparison Project phase, our study reveals a consistent pattern highlighting a fundamental shift in ASI dynamics preceding total loss. We observe increasing fluctuations in the September ASI area as the threshold for an ice-free Arctic is approached across various scenarios and models. This pattern is particularly concentrated in the Central Arctic (CA) sub-region. Spatial analyses reveal increasing variance along the CA's northern coastlines, accompanied by a substantial increase in open water coverage, underscoring the shift from stable to highly variable ice conditions in this region. Additionally, our findings suggest a potential link between increased ASI fluctuations and variability in surface wind speeds. These specific results underscore the urgency of multidisciplinary approaches in addressing the challenges posed by ASI variability, with implications for marine ecosystems, Indigenous communities, and navigational safety.

Description: Detection of critical slowing down (CSD) is the dominant avenue for anticipating critical transitions from noisy time-series data. Most commonly, changes in variance and lag-1 autocorrelation [AC(1)] are used as CSD indicators. However, these indicators will only produce reliable results if the noise driving the system is white and stationary. In the more realistic case of time-correlated red noise, increasing (decreasing) the correlation of the noise will lead to spurious (masked) alarms for both variance and AC(1). Here, we propose two new methods that can discriminate true CSD from possible changes in the driving noise characteristics. We focus on estimating changes in the linear restoring rate based on Langevin-type dynamics driven by either white or red noise. We assess the capacity of our new estimators to anticipate critical transitions and show that they perform significantly better than other existing methods both for continuous-time and discrete-time models. In addition to conceptual models, we apply our methods to climate model simulations of the termination of the African Humid Period. The estimations rule out spurious signals stemming from nonstationary noise characteristics and reveal a destabilization of the African climate system as the dynamical mechanism underlying this archetype of abrupt climate change in the past.