On the expression and distribution of glacial trimlines: a case study of Little Ice Age trimlines on Svalbard

Glacial trimlines are important features for constraining 3-dimensional palaeoglaciological reconstructions, but relatively little is known about the processes of their formation and preservation. A new classification scheme for the expression of glacial trimlines was presented by Rootes and Clark (2020), with the aim to encourage further research into the processes of formation and preservation for trimlines. Here we present the first application of the trimline classification scheme to a case study location in central western Spitsbergen, Svalbard. Little Ice Age trimlines were mapped using remotely sensed imagery and the classification scheme applied. These data are presented and used to examine the factors that may influence the distribution and expression of trimlines in order to explore controls on their formation and preservation. Preliminary analysis suggests that the type of glacier, and geology, particularly the bedrock erodibility, may have an influence over the location and expression of glacial trimlines in Svalbard. These findings open the potential for trimlines to be used as part of diagnostic landsystems for specific types of glacier, such as marine-terminating tidewater glaciers, terrestrial glaciers or surge-type glaciers, and indicates that further research into glacial trimlines may enable these landforms to yield additional information about palaeo-ice masses than has previously been the case

Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination

Reconstructing the dynamic response of the Antarctic ice sheets to warming during the Last Glacial Termination (LGT; 18,000–11,650 yrs ago) allows us to disentangle ice-climate feedbacks that are key to improving future projections. Whilst the sequence of events during this period is reasonably well-known, relatively poor chronological control has precluded precise alignment of ice, atmospheric and marine records, making it difficult to assess relationships between Antarctic ice-sheet (AIS) dynamics, climate change and sea level. Here we present results from a highly-resolved ‘horizontal ice core’ from the Weddell Sea Embayment, which records millennial-scale AIS dynamics across this extensive region. Counterintuitively, we find AIS mass-loss across the full duration of the Antarctic Cold Reversal (ACR; 14,600–12,700 yrs ago), with stabilisation during the subsequent millennia of atmospheric warming. Earth-system and ice-sheet modelling suggests these contrasting trends were likely Antarctic-wide, sustained by feedbacks amplified by the delivery of Circumpolar Deep Water onto the continental shelf. Given the anti-phase relationship between inter-hemispheric climate trends across the LGT our findings demonstrate that Southern Ocean-AIS feedbacks were controlled by global atmospheric teleconnections. With increasing stratification of the Southern Ocean and intensification of mid-latitude westerly winds today, such teleconnections could amplify AIS mass loss and accelerate global sea-level rise

Glacial trimlines to identify former ice margins and subglacial thermal boundaries : a review and classification scheme for trimline expression

Reconstructions of former ice sheets and glaciers provide important palaeoglaciological information about their behaviour in response to climate changes. Glacial trimlines record both the margin positions and palaeo ice thickness, enabling the production of empirically constrained 3-Dimensional reconstructions. However, the literature review into the characteristics, interpretation, and use of glacial trimlines here presented shows that these features have been under-utilised and are poorly described in the existing literature, with a confusing terminology currently in use. A new classification scheme and terminology for trimline identification and interpretation is developed to better facilitate further research into these common features of glacierised and formerly glaciated landscapes

Dual microRNA Screens Reveal That the Immune-Responsive miR-181 Promotes Henipavirus Entry and Cell-Cell Fusion

10.1371/journal.ppat.1005974PLoS Pathogens1210e100597

Genome-wide siRNA Screening at Biosafety Level 4 Reveals a Crucial Role for Fibrillarin in Henipavirus Infection

10.1371/journal.ppat.1005478PLoS Pathogens123e100547

Large-scale analysis of structural brain asymmetries in schizophrenia via the ENIGMA consortium.

Left-right asymmetry is an important organizing feature of the healthy brain that may be altered in schizophrenia, but most studies have used relatively small samples and heterogeneous approaches, resulting in equivocal findings. We carried out the largest case-control study of structural brain asymmetries in schizophrenia, with MRI data from 5,080 affected individuals and 6,015 controls across 46 datasets, using a single image analysis protocol. Asymmetry indexes were calculated for global and regional cortical thickness, surface area, and subcortical volume measures. Differences of asymmetry were calculated between affected individuals and controls per dataset, and effect sizes were meta-analyzed across datasets. Small average case-control differences were observed for thickness asymmetries of the rostral anterior cingulate and the middle temporal gyrus, both driven by thinner left-hemispheric cortices in schizophrenia. Analyses of these asymmetries with respect to the use of antipsychotic medication and other clinical variables did not show any significant associations. Assessment of age- and sex-specific effects revealed a stronger average leftward asymmetry of pallidum volume between older cases and controls. Case-control differences in a multivariate context were assessed in a subset of the data (N = 2,029), which revealed that 7% of the variance across all structural asymmetries was explained by case-control status. Subtle case-control differences of brain macrostructural asymmetry may reflect differences at the molecular, cytoarchitectonic, or circuit levels that have functional relevance for the disorder. Reduced left middle temporal cortical thickness is consistent with altered left-hemisphere language network organization in schizophrenia