Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: a case study from a polythermal glacier in Svalbard

Ice-cored lateral–frontal moraines are common at the margins of receding high-Arctic valley glaciers, but the preservation potential of these features within the landform record is unclear. Recent climatic amelioration provides an opportunity to study the morphological evolution of these landforms as they de-ice. This is important because high-Arctic glacial landsystems have been used as analogues for formerly glaciated areas in the mid-latitudes. This study uses SfM (Structure-from-Motion) photogrammetry and a combination of archive aerial and UAV (unmanned aerial vehicle) derived imagery to investigate the degradation of an ice-cored lateral–frontal moraine at Austre Lovénbreen, Svalbard. Across the study area as a whole, over an 11-year period, the average depth of surface lowering was − 1.75 ± 0.89 m. The frontal sections of the moraine showed low or undetectable rates of change. Spatially variable rates of surface lowering are associated with differences in the quantity of buried ice within the structure of the moraine. Morphological change was dominated by surface lowering, with limited field evidence of degradation via back-wastage. This permits the moraine a greater degree of stability than previously observed at other sites in Svalbard. It is unclear whether the end point will be a fully stabilised ice-cored moraine, in equilibrium with its environment, or an ice-free lateral–frontal moraine complex. Controls on geomorphological change (e.g. topography and climate) and the preservation potential of the lateral–frontal moraine are discussed. The methods used by this research also demonstrate the potential value of SfM photogrammetry and unmanned aerial vehicles for monitoring environmental change and are likely to have wider applications in other geoscientific sub-disciplines

Controls on dryland mountain landscape development along the NW Saharan desert margin: Insights from Quaternary river terrace sequences (Dadès River, south-central High Atlas, Morocco)

This study documents river terraces from upstream reaches of the Dad es River, a major fluvial system draining the south-central High Atlas Mountains. Terraces occur as straths with bedrock bases positioned at 10 m altitudinal intervals up to 40 m (T1-T5) above the valley floor, becoming less common between 50 and 140 m. The rock strength, stratigraphy and structure of the mountain belt influences terrace distribution. Terraces are absent in river gorges of structurally thickened limestone; whilst welldeveloped, laterally continuous terraces (T1-T4) form along wide valleys occupying syncline structures dominated by weaker interbedded limestone-mudstone. Terrace staircases develop in confined canyons associated with weaker lithologies and influence from structural dip and stratigraphic configuration. Terraces comprise a bedrock erosion surface overlain by fluvial conglomerates, rare overbank sands and colluvium. This sequence with some OSL/IRSL age control, suggests terrace formation over a 100 ka climate cycle with valley floor aggradation during full glacials and incision during glacial-interglacial transitions. This integrates with other archives (e.g. lakes, glaciers, dunes), appearing typical of landscape development along the NW Saharan margin south of the High Atlas, and similar to patterns in the western-southern Mediterranean. The 100 ka climate cycle relationship suggests that the terrace sequence documents Late-Middle Pleistocene landscape development. Consistent altitudinal spacing of terraces and their distribution throughout the orogen suggests sustained base-level lowering linked to uplift-exhumation of the High Atlas. Low incision rates (<0.2 mm a 1) and general absence of terrace deformation suggests dominance of isostatically driven base-level lowering with relief generation being Early Pleistocene or older.National Geographic research grant (8609-09

COVID-19: Rapid antigen detection for SARS-CoV-2 by lateral flow assay: A national systematic evaluation of sensitivity and specificity for mass-testing

Background Lateral flow device (LFD) viral antigen immunoassays have been developed around the world as diagnostic tests for SARS-CoV-2 infection. They have been proposed to deliver an infrastructure-light, cost-economical solution giving results within half an hour. Methods LFDs were initially reviewed by a Department of Health and Social Care team, part of the UK government, from which 64 were selected for further evaluation from 1st August to 15th December 2020. Standardised laboratory evaluations, and for those that met the published criteria, field testing in the Falcon-C19 research study and UK pilots were performed (UK COVID-19 testing centres, hospital, schools, armed forces). Findings 4/64 LFDs so far have desirable performance characteristics (orient Gene, Deepblue, Abbott and Innova SARS-CoV-2 Antigen Rapid Qualitative Test). All these LFDs have a viral antigen detection of >90% at 100,000 RNA copies/ml. 8951 Innova LFD tests were performed with a kit failure rate of 5.6% (502/8951, 95% CI: 5.1–6.1), false positive rate of 0.32% (22/6954, 95% CI: 0.20–0.48). Viral antigen detection/sensitivity across the sampling cohort when performed by laboratory scientists was 78.8% (156/198, 95% CI 72.4–84.3). Interpretation Our results suggest LFDs have promising performance characteristics for mass population testing and can be used to identify infectious positive individuals. The Innova LFD shows good viral antigen detection/sensitivity with excellent specificity, although kit failure rates and the impact of training are potential issues. These results support the expanded evaluation of LFDs, and assessment of greater access to testing on COVID-19 transmission. Funding Department of Health and Social Care. University of Oxford. Public Health England Porton Down, Manchester University NHS Foundation Trust, National Institute of Health Research

Search for annual and diurnal rate modulations in the LUX experiment

Various dark matter models predict annual and diurnal modulations of dark matter interaction rates in Earth-based experiments as a result of the Earth’s motion in the halo. Observation of such features can provide generic evidence for detection of dark matter interactions. This paper reports a search for both annual and diurnal rate modulations in the LUX dark matter experiment using over 20 calendar months of data acquired between 2013 and 2016. This search focuses on electron recoil events at low energies, where leptophilic dark matter interactions are expected to occur and where the DAMA experiment has observed a strong rate modulation for over two decades. By using the innermost volume of the LUX detector and developing robust cuts and corrections, we obtained a stable event rate of 2.3±0.2  cpd/keVee/tonne, which is among the lowest in all dark matter experiments. No statistically significant annual modulation was observed in energy windows up to 26  keVee. Between 2 and 6  keVee, this analysis demonstrates the most sensitive annual modulation search up to date, with 9.2σ tension with the DAMA/LIBRA result. We also report no observation of diurnal modulations above 0.2  cpd/keVee/tonne amplitude between 2 and 6  keVee.Various dark matter models predict annual and diurnal modulations of dark matter interaction rates in Earth-based experiments as a result of the Earth's motion in the halo. Observation of such features can provide generic evidence for detection of dark matter interactions. This paper reports a search for both annual and diurnal rate modulations in the LUX dark matter experiment using over 20 calendar months of data acquired between 2013 and 2016. This search focuses on electron recoil events at low energies, where leptophilic dark matter interactions are expected to occur and where the DAMA experiment has observed a strong rate modulation for over two decades. By using the innermost volume of the LUX detector and developing robust cuts and corrections, we obtained a stable event rate of 2.3$\pm$0.2~cpd/keV$_{\text{ee}}$/tonne, which is among the lowest in all dark matter experiments. No statistically significant annual modulation was observed in energy windows up to 26~keV$_{\text{ee}}$. Between 2 and 6~keV$_{\text{ee}}$, this analysis demonstrates the most sensitive annual modulation search up to date, with 9.2$\sigma$ tension with the DAMA/LIBRA result. We also report no observation of diurnal modulations above 0.2~cpd/keV$_{\text{ee}}$/tonne amplitude between 2 and 6~keV$_{\text{ee}}$

Tectonic and sedimentary evolution of the Cenozoic Hatay Graben, Southern Turkey: A two-phase model for graben formation

New structural and sedimentary studies form the basis of a new interpretation for the Neogene Hatay Graben. Fault analysis reveals three contemporaneous trends of fault orientation (000°-180°, 045°-225° and 150°-350°) suggesting that the graben is transtensional in nature. Sedimentary studies show that, following shallow-marine deposition from the Late Cretaceous to the Eocene, a hiatus ensued until Early Miocene fluvial sedimentation. After a Mid-Miocene marine transgression, water depths increased until the Messinian salinity crisis, followed by a regression from the Pliocene to the present day. The basin initially developed as the distal margin of a foreland basin of the Tauride allochthon to the north, developing a classic sedimentary sequence during Mid-Late Miocene. Stresses caused by loading of the crust created a flexural forebulge to the south that supplied sediment mainly northwards. During the Plio-Quaternary, transtensional graben development took place, primarily influenced by the westward tectonic escape of Anatolia along the East Anatolia Fault Zone and left-lateral offset along the northward extension of the Dead Sea Transform Fault. This area is, thus, an excellent example of a foreland basin reactivated in a strike-slip setting. Our new two-phase model: foreland basin, then transtensional basin for the Hatay Graben, is in contrast to previous models, in which it was generally assumed that the Plio-Quaternary Hatay Graben represents a direct extension of the Dead Sea Fault Zone or the East Anatolian Fault Zone. © The Geological Society of London 2006

Caenorhabditis elegans POLQ-1 and HEL-308 function in two distinct DNA interstrand cross-link repair pathways

DNA interstrand cross-links (ICLs) are highly cytotoxic DNA lesions hindering DNA replication and transcription. Whereas in bacteria and yeast the molecular mechanisms involved in ICL repair are genetically well dissected, the scenario in multicellular organisms remains unclear. Here, we report that the two new mus308 genes, polq-1 and hel-308 are involved in ICL repair in Caenorhabditis elegans. After treatment with ICL agents, a decrease in survival and an increase in checkpoint-induced cell cycle arrest and apoptosis of germ cells is observed in mutants of both genes. Although sensitive to ICL agents and to a minor extent to IR radiation, cytological and epistatic analyses suggest that polq-1 and hel-308 are involved in different DNA repair pathways. While hel-308 functions in a Fanconi anemia dependent pathway, polq-1 has a role in a novel distinct and brc-1 (CeBRCA1)-dependent ICL repair process in metazoans