This paper takes a geoarchaeological contextual approach in arguing that pavement quarries—those assay and reduction events directed at cobbles that often litter expansive desert alluvial landforms—can provide a powerful index of changing trans-Holocene settlement organization. Focusing on multiple lines of evidence—age estimates of alluvial fan surfaces, quarry technology, patination pro les, and regional toolstone consumption trends at residential sites—we explore the temporal and technological development of quarry pavement use at the National Training Center at Fort Irwin, Mojave Desert. The analysis reveals that chert pavement quarrying was in ascendance during the early portion of the Late Holocene and had a strong biface production component. This landform-based model of Holocene pavement quarry development provides support for reconstructions that envision Gypsum period hunter-gatherers as residentially stable, and as undertaking increased logistical forays during which pavement quarry procurement took place.

De Haas–van Alphen measurements in CexLa1-xB6 intermetallics reveal the existence of long-lived quasiparticles for all 0

Biochemical and biomechanical extracellular matrix (ECM) cues have recently been shown to play a role in stimulating stem cell differentiation towards several lineages, though how they combine to induce adipogenesis has been less well studied. The objective of this study was to recapitulate both the ECM composition and mechanical properties of adipose tissue in vitro to stimulate adipogenesis of human adipose-derived stem cells (ASCs) in the absence of exogenous adipogenic growth factors and small molecules. Adipose specific ECM biochemical cues have been previously shown to influence adipogenic differentiation; however, the ability of biomechanical cues to promote adipogenesis has been less defined. Decellularized human lipoaspirate was used to functionalize polyacrylamide gels of varying stiffness to allow the cells to interact with adipose-specific ECM components. Culturing ASCs on gels that mimicked the native stiffness of adipose tissue (2 kPa) significantly upregulated adipogenic markers, in the absence of exogenous adipogenic growth factors and small molecules. As substrate stiffness increased, the cells became more spread, lost their rounded morphology, and failed to upregulate adipogenic markers. Together these data imply that as with other lineages, mechanical cues are capable of regulating adipogenesis in ASCs.

In this paper, we briefly review some recent de Haas-van Alphen experiments on two contrasting types of heavy fermion/Kondo systems for varying concentrations x of the impurity ion, Ce or U. In both systems the Fermi surface is observed to vary continuously with x: in CexLa1-xB6, the Ce ions behave as Kondo impurities while in UxTh1-xBe13 they do not. In both systems, the f electrons are also found to contribute only partially to the Fermi surface volume, therefore raising questions concerning the applicability of Fermi liquid theory.

Under the Kigali Amendment to the Montreal Protocol, new controls are being implemented to reduce emissions of HFC-23 (CHF[Formula: see text]), a by-product during the manufacture of HCFC-22 (CHClF[Formula: see text]). Starting in 2015, China and India, who dominate global HCFC-22 production (75% in 2017), set out ambitious programs to reduce HFC-23 emissions. Here, we estimate that these measures should have seen global emissions drop by 87% between 2014 and 2017. Instead, atmospheric observations show that emissions have increased and in 2018 were higher than at any point in history (15.9 [Formula: see text]). Given the magnitude of the discrepancy between expected and observation-inferred emissions, it is likely that the reported reductions have not fully materialized or there may be substantial unreported production of HCFC-22, resulting in unaccounted-for HFC-23 by-product emissions. The difference between reported and observation-inferred estimates suggests that an additional ~309 Tg [Formula: see text]-equivalent emissions were added to the atmosphere between 2015 and 2017.

The grounding line is a key element of coastal outlet glaciers, acting on their dynamics. Accurately knowing its position is fundamental for both modelling the glacier dynamics and establishing a benchmark for later change detection. Here we map the grounding line of the Astrolabe Glacier in East Antarctica (66°41' S, 140°05' E), using both hydrostatic and tidal methods. The first method is based on new surface and ice thickness data from which the line of buoyant floatation is found. The second method uses kinematic GPS measurements of the tidal response of the ice surface. By detecting the transitions where the ice starts to move vertically in response to the tidal forcing we determine control points for the grounding line position along GPS profiles. Employing a two-dimensional elastic plate model, we compute the rigid short-term behaviour of the ice plate and estimate the correction required to compare the kinematic GPS control points with the previously determined line of floatation. These two approaches show consistency and lead us to propose a grounding line for the Astrolabe Glacier that significantly deviates from the lines obtained so far from satellite imagery. © Author(s) 2014. CC Attribution 3.0 License.

The 1,1,1,2-tetrafluoroethane (HFC-134a), an important alternative to CFC-12 in accordance with the Montreal Protocol on Substances that Deplete the Ozone Layer, is a high global warming potential greenhouse gas. Here we evaluate variations in global and regional HFC-134a emissions and emission trends, from 1995 to 2010, at a relatively high spatial and temporal (3.75° in longitude × 2.5° in latitude and 8 day) resolution, using surface HFC-134a measurements. Our results show a progressive increase of global HFC-134a emissions from 19 ± 2 Gg/yr in 1995 to 167 ± 5 Gg/yr in 2010, with both a slowdown in developed countries and a 20%/yr increase in China since 2005. A seasonal cycle is also seen since 2002, which becomes enhanced over time, with larger values during the boreal summer.