Decimetre-scale carbonaceous macrofossils from the Mesoproterozoic Gaoyuzhuang Formation in the Yanshan Range are known as the current oldest unambiguous evidence of macroscopic multicellular eukaryotes. Here, we reported a new SIMS zircon age of 1588.8 ± 6.5 Ma from a volcanic tuff in the Qianxi County of Hebei Province, about 11 m above the macrofossil’s horizon. This new age provides a direct age constraint on the macroscopic eukaryotic fossils from the Gaoyuzhuang Formation. It indicates that macroscopic life with the moderate diversity and certain morphological complexity had already evolved at the beginning of the Mesoproterozoic, and implies a possibility of discovering macroscopic eukaryotes in earlier rocks. This study also calls for a stratigraphic framework to integrate biological and environmental studies in different regions for a better understanding of the evolution of multicellular organisms and environmental change during this important period.

Analytical data from aqueous dissolution studies of minerals, mineral systems, and naturally equilibrated solutions such as surface waters and groundwaters provide the basic ingredients necessary to calculate comparative solubility (or activity) products (CKs) and comparative free energies of formation (CΔGf0) of possible minerals or hypothetical minerals. Using a thermodynamic approach, quasi-thermodynamic values are obtained which can help in understanding the relative stabilities of different but similar materials and changes in reacting systems. Illite equilibrated solutions demonstrated that: 1) there is a 5 kcal spread in comparative free energies of formation of the five illites used, 2) the comparative stabilities remain about the same when highly simplified but similar hypothetical mineral formulas are considered, and 3) some of these illites are probably not the most stable phase in a closed chemical system at standard temperature and pressure.

A “mineral index system” composed of common rock-forming minerals, products of chemical weathering and perhaps hypothetical minerals is proposed, which offers a means of studying naturally equilibrated solutions. Such a system can show changes with respect to CΔGf0 of these minerals at a particular site through time or in relationship to spatial distribution and geologic changes through synchronous sampling at different sites.

Electron probe analyses of diagenetic illites in Eocene sandstones from Kettleman North Dome, California, along with analyses of coexisting interstitial waters were used to calculate apparent molal free energies of formation of the illites at the in situ conditions of 100°C and 150 bars. Various triangular and rectangular compositional plots, once contoured for free energy, crudely indicate that the free energy decreases as the potassium content increases, decreases as the Al-for-Si substitution increases, and appears to be a minimum along a narrow composition valley having ~3% Fe2O3 of octahedral cations. Qualitatively, the shape of the free energy surface suggests only small departures from ideality.

The illites and water samples used in the calculations were chosen as close to each other as possible and are in equilibrium. The waters contain mainly Cl−, SO42−, Na+, and Ca2+ and have a total salinity of ~10,000 ppm. The illites, which coexist in the sandstones with diagenetic quartz, albite, and K-feldspar, are phen-gitic and contain 5–9% K2O, 1–3% total FeO, 1% MgO, and minor Na2O, MnO, and TiO2. The Fe2O3/FeO ratio has been set arbitrarily to 7 by comparison with published analyses.

Log K (100°C) was first calculated for the equilibrium illite ⇄ ions from the ionic activities obtained through speciation calculations for each water sample. The apparent free energies of formation of illites at 100°C were then calculated. The effect of instrumental uncertainty on the values of ΔGf was assessed by accepting a 2.5 or 3.5% error in the probe analyses and by using a Monte Carlo method of error propagation. The free energies of formation obtained (on the basis of O10(OH2)) range from -1280 to -1320 kcal/mole at 100°C and 150 bars, and their Monte-Carlo uncertainties are less than ±2 kcal/mole. Combining the compositions of natural, coexisting aqueous solutions and mineral solid solutions through thermodynamic equations constitutes a fast method to determine, at least crudely, the free energy-composition surface for the solid solution. This is in contrast to experimental methods such as calorimetry or hydrothermal equilibrium, which are very time-consuming and difficult.

How do non-state armed groups form in intra-state armed conflicts? Researchers have started to disaggregate armed groups, but we still know little about how armed groups emerge in different ways. Drawing on the literature on social movements, civil wars, and civil–military relations, we generate a typology of ‘movement’, ‘insurgent’, and ‘state splinter’ origins of armed groups. We argue that fundamentally different dynamics of conflict shape armed group origins in the context of broad-based mobilisation, peripheral challenges to the state, and intra-regime fragmentation. Armed groups that emerge in these contexts in general differ in their initial membership and leadership, the basic organisational dimensions that we focus on. We demonstrate the utility of our typology by mapping different origins of armed groups onto existing cross-national data and charting type narratives in illustrative cases. This discussion advances recent efforts to understand the importance of armed group emergence for outcomes of interest to conflict scholars by moving beyond either separate types of origins or highly disaggregated organisational analyses to broader conflict dynamics through which armed groups form, with implications for how these groups act. Future research should consider different origins which we identify in comparison through an in-depth analysis of armed groups’ complex histories.

Although the theology of Tradition of the Dominican Yves Congar was highly influential in drafting the Dogmatic Constitution Dei Verbum at the Second Vatican Council, postconciliar debates neglected some of the most original aspects of this theology. This article proposes a retrieval of the notion of Tradition as ‘milieu éducatif’, advanced by the theologian in Tradition and Traditions, as a valuable resource for contemporary discussions on Christian formation. It intends to highlight how Congar connected the theological realities of revelation and its transmission by the Church with the concrete practice of Christian life. This notion is, then, put in conversation with contemporary Christian thinkers who have reflected on the practical aspects of Christian formation, chiefly James K.A. Smith. This dialogue aims to show the relevance of Congar’s notion to current discussions. While the theology of Tradition exposed by the French Dominican can be completed and specified by current proposals, it can also offer a new theological depth to those proposals.

In this article, I argue for the centrality of prayer within Christian interpretation of scripture. This argument is made in two stages. First, Christ on the road to Emmaus is the interpreter of scripture par excellence, such that scriptural interpretation is fruitfully understood as participation in Christ's interpretation of scripture to and for the church. Second, scriptural interpretation must take prayer as central to an appropriate scriptural hermeneutics, since prayer is one way in which the reader of scripture becomes conformed to person of Christ.

This article will consider James K.A. Smith’s proposal for Christian educational reform by examining the historical animating principles and the contemporary embodied practices of Episcopal boarding schools in the United States. Drawing on historical accounts of the early years of Episcopal boarding schools, this paper will surface resonances between Smith’s vision for Christian education and the hopes of the first rectors of Episcopal boarding schools. Moving from the founding of these schools to their contemporary configurations, this paper will draw on ethnographic accounts of Episcopal boarding schools to complicate Smith’s vision of the formative Christian school. Ethnographic accounts of Episcopal schools offer further support for Smith’s cultural liturgies paradigm; at the same time, the concrete realities of Episcopal boarding schools will call into question Smith’s convictions regarding the potential for Christian schools to operate counter-liturgically. A consideration of the Episcopal Church’s ecclesial mission will demonstrate how it departs from Smith’s post-liberal ecclesiology to suggest realistic ways forward in the negotiation of Christian identity and practice in the context of Episcopal boarding schools.

This contribution is based on the work published by (Pinzón et al. 2021) in which we computed rotation rates for a sample of 79 young stars (∼3 Myr) in a wide range of stellar masses (from T Tauri Stars to Herbig Ae/Be stars) in in the Orion Star Formation Complex (OSFC). We study whether the magnetospheric accretion scenario (MA), valid for young low mass stars, may be applied over a wide range of stellar masses of not. Under the assumption that stellar winds powered by stellar accretion are the main source for the stellar spin down, the hypothesis of an extension of MA toward higher masses seems plausible. A comparison with Ap/Bp stars suggest that HAeBes should suffer a loss of angular momentum by a factor between 12 and 80 during the first 10 Myr in order to match the magnetic Ap/Bp zone in HR diagram.

Photoelectric effect of dust grains by UV radiation is an important process for disk heating, but as a disk evolves, the amount of dust grains decreases. Photoeaporation is a disk dispersal process, which is caused by high-energy radiation. We perform a set of photoevaporation simulations solving hydrodynamics with radiative transfer and non-equilibrium chemistry in a self-consistent way. We run a series of simulations with varying the dust-to-gas mass ratio in a range . We show that H2 pumping and X-ray heating mainly contribute to the disk heating in case of and photoelectric effect mainly heats the gas in cases. The mass-loss profile changes significantly with respect to the main heating process. The outer disk is more efficiently dispersed when photoelectric effect is the main heating source.