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Stem-cell-specific genes regulate processes such as maintenance, identity and/or division. Here, the authors show that in the Arabidopsis root TCX2, a gene expressed across different stem cell populations (a stem-cell-ubiquitous gene), controls division and identity by regulating stem-cell-type-specific networks.

Carbonaceous shales in the Southern Uplands-Down-Longford Terrane accretionary prism had extremely high potential for hydrocarbon generation in the Lower Paleozoic. Structural thickening in the prism enhanced the rapid generation of oil. Shale horizons are separated by thick turbidites composed of low-permeability greywackes, so oil under high fluid pressure either pooled along shale bedding surfaces or migrated into fractured greywackes. Pooled oil became solidified to bitumen, which locally formed deposits on a scale of tonnes, mined as coal. The carbon-rich shale also sequestered large amounts of sulfur from seawater, which precipitated as pyrite firstly during early diagenesis, then further during fluid flow through the shale beds. The oil was also sulfur-bearing. Deformation focused on the shale beds during the evolution of the accretionary prism would have been closely related to the fluid flow which precipitated bitumen and sulfides. The palaeo-fluids were also anomalously rich in methane and hydrogen, similar to fluids venting from modern accretionary prisms. Supplementary material: details of localities searched for coal in Lower Palaeozoic, Southern Uplands-Down-Longford Terrane (locations shown in Fig. 6) are available at https://doi.org/10.6084/m9.figshare.c.6691597 [ABSTRACT FROM AUTHOR]

The Lower Devonian plant-bearing Rhynie Chert, Aberdeenshire, UK, consists of sinters deposited by a hot spring system. Like many modern hot springs, the Rhynie geothermal system was lithium-rich, and its silica deposits are richer in lithium than other current or fossil sinters. Twenty samples of Rhynie sinter have a mean content of 255 ppm lithium. The high values imply exceptional lithium contents in the spring waters. Together with pegmatites and granites in the same region, the chert is related to a lithium-rich Late Caledonian magmatic suite, of which it is a surface expression. The measurements suggest that ancient hot spring deposits could provide valuable data during the exploration for lithium. Supplementary material: Supplementary Table 1 (compositional data for Late Caledonian granites) is available at https://doi.org/10.6084/m9.figshare.c.6756506 [ABSTRACT FROM AUTHOR]

Marble in the supracrustal rocks of the Lewisian Complex, Tiree, includes chlorine-bearing amphiboles, chlorine-rich apatite, sulphur-rich scapolite, albite and phlogopite, all of which are regarded as evidence for evaporites in other metamorphosed sequences. Titanite yields U–Pb ages of ∼1.6 Ga, i.e. late Laxfordian, which excludes a younger imprint of sodium metasomatism. Traces of anhydrite, and isotopically heavy pyrite, also indicate deposition from seawater. Elsewhere in the Hebrides, tourmaline in Lewisian Complex marbles may represent seafloor exhalative deposits. Combined, the evidence suggests Lewisian Complex supracrustal marbles formed in an evaporative environment, like other Palaeoproterozoic successions across the North Atlantic region. [ABSTRACT FROM AUTHOR]

Thermal conductivity of natural rock is only well characterized for temperatures above 273 K, i.e., at typical Earth values. In planetary science, there is a requirement to explore the thermal characteristics of rock at temperatures below 273 K, for which thermal conductivity data are sparse or contested. Here, we present empirical data for a basalt showing thermal conductivity ranging from 2.71 ± 0.09 W m−1 K−1 at 224.4 K, to 2.63 ± 0.05 W m−1 K−1 at 288.8 K. Previous work reports much lower values in this range, which may be due to the fragmented nature of the previous research, the use of powdered samples for some data, and the effect of porosity. The high‐temperature thermal conductivity laws of Sass et al. (1992) and Haenel and Zoth (1973) can be robustly extrapolated to cover the temperature range of our data. [ABSTRACT FROM AUTHOR]