In calcites and dolomites in seven African carbonatites, SrO, FeO and MnO occur in concentrations from 1 to 2 wt.%, whereas Ce, Y, Cu and Zn occur only at the ppm level. Sr, Ce and Y partition preferentially into calcite relative to co-existing dolomite, whereas Fe and Mn favour dolomite. Sr partitions preferentially into calcite relative to co-exisiting apatite, but the light rare-earth elements partition into apatite. Magnetite from Kerimasi contains up to 13 wt.% MgO and 6 wt.% MnO, extending the known ranges in composition of magnetites from carbonatites.

Optical frequency standards, or lasers stabilized to atomic or molecular transitions, are widely used in length metrology and laser ranging, provide a backbone for optical communications and lie at the heart of next-generation optical atomic clocks. Here we demonstrate a compact, low-power optical frequency reference based on the Doppler-free, two-photon transition in rubidium-87 at 778 nm implemented on a micro-optics breadboard. Our optical reference achieves a fractional frequency instability of 2.9×10−12/ τ for averaging times τ less than 103 s, has a volume of ≈35 cm3 and operates on ≈450 mW of electrical power. The advanced optical integration presented here demonstrates a key step towards the development of compact optical clocks and the broad dissemination of SI-traceable wavelength references.

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In a nuclear war, volcanic eruption, asteroid or comet impact that causes an abrupt sunlight reduction scenario (ASRS), agricultural yields would plummet. Global society is currently unprepared for such an event, implying an urgent need for evaluation and prioritization of solutions. We show effective deployment of resilient food solutions appears sufficient to fulfill global energy and macronutrient food requirements, potentially saving billions from famine. A Monte Carlo analysis of resilient food outcomes, using a linear optimization model, shows a 95% probability of global food availability between 2,100 and 3,500 Kcals per capita per day in a nuclear winter scenario involving 150 Tg of soot in the stratosphere. Our analysis indicates nutritionally sufficient diets from resilient foods would be widely affordable, costing US$1.73 daily, though subsidization could be needed across Southern Asia and Sub-Saharan Africa. Post-disaster conflict or insufficient international cooperation could increase costs and reduce output, hampering effective resilient food deployment.

A new large-volume, high-pressure facility is being utilized and developed as part of GeoSoilEnviroCARS at a third-generation synchrotron, the Advanced Photon Source. This user facility consists of two large-volume presses (LVP), a 2.5 MN (250 ton) LVP installed at the bending magnet beamline, and a 10 MN (1000 ton) LVP at the insertion device beamline. Here we report some techniques currently being developed with the 10 MN LVP and the latest scientific results obtained using the 2.5 MN LVP.

The focus of this work is to determine the type of interparticle forces that are primarily responsible for the rheology control of high solids solvent borne coatings containing polymer microgels. Rheological behavior is an important consideration when formulating high solids coatings due to the relatively low viscosities required for sufficient atomization during spray application and the difficulty of preventing the film from sagging during the bake cycle. Rheology control agents such as microgels are used to modify rheological properties where solvent evaporation is insufficient during the bake cycle to prevent sagging.In this paper that describes the first phase of our work, we have characterized several microgel dispersions used as rheology control agents in high solids automotive topcoats using scanning electron microscopy (SEM) and steady shear viscosity measurements. The steady shear viscosity versus microgel volume fraction data was compared with the expected behavior of ideal hard sphere dispersions. One of the microgel dispersions showed very nearly ideal behavior while others deviated from the expected behavior at higher volume fractions. We have also investigated the steady shear behavior of increasing concentrations of microgel dispersions added to low molecular weight acrylic polymer, typical of resins used in high solids automotive coatings. These microgel dispersions induce a yield stress in the Newtonian resin that shows a strong dependence on microgel particle concentration.

The digital transformation of societies has been a core concern for the information systems (IS) research community since its emergence. While most of this work has had a positive outlook, recently a stronger focus on the unintended consequences and dark side of digitalization has come to the fore. This paper contributes to this emerging stream of research by zooming in on a heretofore unrecognized question with potentially catastrophic consequences: What happens to our increasingly digitalized societies when a pro-longed blackout causes a large fraction of digital systems and services to stop working for an extended period of time? To answer this motivating question, we conducted two system dynamics-based simulation experiments to tease out how different degrees of digitalization in a society would affect the resilience of the food system in the face of two different, extreme but plausible prolonged blackout scenarios. We find that a high degree of digitalization has a strong significant negative impact on food system resilience in the investigated scenarios. In the discussion of our findings, we conceptualize “the risk of digital fragility” as the underlying driver of the observed results. Moving forward, we suggest seven mitigation strategies for the risk of digital fragility as fruitful avenues for future research.

<p>Modern civilization is highly dependent on industrial agriculture. Industrial agriculture in turn has become an increasingly complex and globally interconnected system whose historically unprecedented productivity relies strongly on external energy inputs in the shape of machinery, mineral fertilizers, and pesticides. It leaves the system vulnerable to disruptions of industrial production and international trade. Several scenarios have the potential to damage electrical infrastructure on a global scale, including electromagnetic pulses caused by solar storms or the detonation of nuclear warheads in the upper atmosphere, as well as a globally coordinated cyber-attack. The current COVID-19 pandemic has highlighted the importance of crisis preparation and the establishment of more resilient systems. To improve preparation for high-stake risk scenarios their impact especially on critical supply systems must be better understood. To further the understanding of consequences for the global food system this work aims to estimate the effect the global inhibition of industrial production could have on the crop yields of maize, rice, soybean, and wheat. A generalized linear model with a gamma distribution was calibrated on current crop-specific gridded global yield datasets at five arcmin resolution. Gridded datasets on the temperature regime, the moisture regime, soil characteristics, nitrogen, phosphorus and pesticide application rates, the fraction of irrigated area and a proxy to determine whether farm activities are mechanized were chosen as explanatory variables. The model was then used to predict crop yields in two phases following a global catastrophe which inhibits the usage of any electric services. Phase 1 reflects conditions in the year immediately after the catastrophe, assuming the existence of fertilizer, pesticides, and fuel stocks. In phase 2 all stocks are used up and artificial fertilizer, pesticides and fuel are not available anymore. The predictions showed a reduction in yield of 10-30% in phase 1 and between 34 and 43% in phase 2. Overall Europe, North and South America and large parts of India, China and Indonesia are projected to face major yield reductions of up to 95% while most African countries are scarcely affected. The findings clearly indicate hotspot regions which align with the level of industrialization of agriculture. Further, it is shown that the yield reduction is likely to be substantial, especially in industrialized countries. The analysis also provides insights on major factors influencing crop yield under losing industry circumstances. Due to data unavailability some crucial factors could not be included in the model, but their qualitative discussion leads to the conclusion that the presented results can be considered an optimistic scenario, and that further research is needed to quantify the impact of the omitted aspects. </p>