Electron microscopy is uniquely suited for atomic-resolution imaging of heterogeneous and complex materials, where composition, physical, and electronic structure need to be analyzed simultaneously. Historically, the technique has demonstrated optimal performance at room temperature, since practical aspects such as vibration, drift, and contamination limit exploration at extreme temperature regimes. Conversely, quantum materials that exhibit exotic physical properties directly tied to the quantum mechanical nature of electrons are best studied (and often only exist) at extremely low temperatures. As a result, emergent phenomena, such as superconductivity, are typically studied using scanning probe-based techniques that can provide exquisite structural and electronic characterization, but are necessarily limited to surfaces. In this article, we focus not on the various methods that have been used to examine quantum materials at extremely low temperatures, but on what could be accomplished in the field of quantum materials if the power of electron microscopy to provide structural analysis at the atomic scale was extended to extremely low temperatures.

We use apatite fission track ages from sediments recovered by the International Ocean Discovery Program in the Laxmi Basin, Arabian Sea, to constrain exhumation rates in the western Himalaya and Karakoram since 15.5 Ma. With the exception of a Triassic population in the youngest 0.93 Ma samples supplied from western Peninsular India, apatite fission track ages are overwhelmingly Cenozoic, largely <25 Ma, consistent with both a Himalaya–Karakoram source and rapid erosion. Comparison of the minimum cooling age of each sample with depositional age (lag time) indicates an acceleration in exhumation between 7.8 and 7.0 Ma, with lag times shortening from ∼6.0 Myr at 8.5–7.8 Ma to being within error of zero between 7.0 and 5.7 Ma. Sediment supply at 7.0–5.7 Ma was largely from the Karakoram, and to a lesser extent the Himalaya, based on U–Pb zircon ages from the same samples. This time coincides with a period of drying in the Himalayan foreland caused by weaker summer monsoons and Westerly winds. It also correlates with a shift of erosion away from the Karakoram, Kohistan and the Tethyan Himalaya towards more erosion of the Lesser and Greater Himalaya and Nanga Parbat, as shown by zircon U–Pb provenance data, and especially after 5.7 Ma based on Nd isotope data. Samples younger than 5.7 Ma have lag times of ∼4.5 Myr, similar to Holocene Indus delta sediments.

The Ross Ice Shelf (RIS) is host to a broadband, multimode seismic wavefield that is excited in response to atmospheric, oceanic and solid Earth source processes. A 34-station broadband seismographic network installed on the RIS from late 2014 through early 2017 produced continuous vibrational observations of Earth's largest ice shelf at both floating and grounded locations. We characterize temporal and spatial variations in broadband ambient wavefield power, with a focus on period bands associated with primary (10–20 s) and secondary (5–10 s) microseism signals, and an oceanic source process near the ice front (0.4–4.0 s). Horizontal component signals on floating stations overwhelmingly reflect oceanic excitations year-round due to near-complete isolation from solid Earth shear waves. The spectrum at all periods is shown to be strongly modulated by the concentration of sea ice near the ice shelf front. Contiguous and extensive sea ice damps ocean wave coupling sufficiently so that wintertime background levels can approach or surpass those of land-sited stations in Antarctica.

Schmidt-hammer exposure-age dating (SHD) of boulders on cryoplanation terrace treads and associated bedrock cliff faces revealed Holocene ages ranging from 0 ± 825 to 8890 ± 1185 yr. The cliffs were significantly younger than the inner treads, which tended to be younger than the outer treads. Radiocarbon dates from the regolith of 3854 to 4821 cal yr BP (2σ range) indicated maximum rates of cliff recession of ~0.1 mm/yr, which suggests the onset of terrace formation before the last glacial maximum. Age, angularity, and size of clasts, together with planation across bedrock structures and the seepage of groundwater from the cliff foot, all support a process-based conceptual model of cryoplanation terrace development in which frost weathering leads to parallel cliff recession and, hence, terrace extension. The availability of groundwater during autumn freezeback is viewed as critical for frost wedging and/or the growth of segregation ice during prolonged winter frost penetration. Permafrost promotes cryoplanation by providing an impermeable frost table beneath the active layer, focusing groundwater flow, and supplying water for sediment transport by solifluction across the tread. Snow beds are considered an effect rather than a cause of cryoplanation terraces, and cryoplanation is seen as distinct from nivation.

This study focuses on Jewish refugee children who fled the Third Reich after the Kristallnacht in November 1938 either using the so-called Kindertransport (Children’s Transport) or by crossing the border illegally. Many parents, desperate after the Kristallnacht, sent their children abroad alone. About 1,800 arrived in the Netherlands. While for some the Netherlands was an intermediate stop, many stayed. We use a mixed-method approach with the aim of providing a better understanding of the survival rates of refugee children using information from several sources. The qualitative research provides illustrative individual experiences of child refugees and facilitates the formulation of hypotheses of settlement trajectories on risks of deportation and being killed, which are then tested using a quantitative approach. Gathering information into a database allows us to estimate the risk associated the living situation and place in the Netherlands. Among 863 Kindertransport children staying in the Netherlands in July 1942, 74 percent were deported and of those deported 81 percent were killed. Differences in settlement trajectories resulted in different risks of deportation and death. Children living with family or relatives had a higher risk of being deported than those living with foster parents or in institutions. Children living with foster parents had a similar risk of deportation to those living in institutions. Changing household type did not alter risk of deportation, while moving places increased this risk. Children deported from foster parents’ households had an increased risk of death after deportation compared to those deported from institutions, indicating an enduring effect of household type.

Harbour (2016) argues for a parsimonious universal set of features for grammatical person distinctions, and suggests (ch. 7) that the same features may also form the basis for systems of deixis. We apply this proposal to an analysis of Heiltsuk, a Wakashan language with a particularly rich set of person-based deictic contrasts (Rath 1981). Heiltsuk demonstratives and third-person pronominal enclitics distinguish proximal-to-speaker, proximal-to-addressee, and distal (in addition to an orthogonal visibility contrast). There are no forms marking proximity to third persons (e.g., ‘near them’) or identifying the location of discourse participants (e.g., ‘you near me’ vs. ‘you over there’), nor does the deictic system make use of the clusivity contrast that appears in the pronoun paradigm (e.g., ‘this near you and me’ vs. ‘this near me and others’). We account for the pattern by implementing Harbour's spatial element χ as a function that yields proximity to its first- or second-person argument.

New radiocarbon (14C) dates suggest a simultaneous appearance of two technologically and geographically distinct axe production practices in Neolithic Britain; igneous open-air quarries in Great Langdale, Cumbria, and from flint mines in southern England at ~4000–3700 cal BC. In light of the recent evidence that farming was introduced at this time by large-scale immigration from northwest Europe, and that expansion within Britain was extremely rapid, we argue that this synchronicity supports this speed of colonization and reflects a knowledge of complex extraction processes and associated exchange networks already possessed by the immigrant groups; long-range connections developed as colonization rapidly expanded. Although we can model the start of these new extraction activities, it remains difficult to estimate how long significant production activity lasted at these key sites given the nature of the record from which samples could be obtained.

The high precision offered by small-scale mechanical testing has allowed the relationships between mechanical behavior and specific microstructural features to be determined to an unprecedented degree. However, of most interest to scientists and engineers is often the behavior of materials under service conditions in an extreme environment, such as high/low temperatures, high strain rates, hydrogen atmosphere, or radiation. In this article, we detail progress made to adapt nanomechanical testing systems and techniques to observe materials behavior in situ in extreme environments.