A palaeo-glaciological reconstruction of the last Irish Ice Sheet.

An inversion of the glacial geomorphological record provides an effective means to reconstruct former ice sheets at ice sheet-scale. The last Irish Ice Sheet has a long history of investigation, but its most basic properties are debated. Much previous research, based on an incremental development of knowledge through field observation of glacigenic landforms and deposits, has locally yielded high levels of detail but this detail is spatially fragmented across the former ice sheet bed. The evidence-base for ice sheet reconstruction is therefore patchy and incomplete, and its internal inconsistencies make an ice sheet reconstruction, via this approach, problematic. This thesis explores new opportunities for palaeo-glaciological reconstruction offered by remotely sensed data. Systematic glacial landform mapping has been conducted throughout Ireland from a variety of satellite imagery and digital elevation models, and yields new Glacial Maps for Ireland comprising >39,000 landforms. These landform maps are the building blocks for a palaeo-glaciological reconstruction of the ice sheet. Adopting a 'flowset' approach, the full population of landform data is summarised as discrete cartographic units - flowsets - and their spatial, temporal and glaciodynamic information is extracted. The flowset record, integrated with the wealth of evidence and dating constraints in the literature, stimulates a reconstruction describing seven broad stages of ice sheet history. These provide a framework for the evolution of the last Irish Ice Sheet. Key elements of the reconstruction confirm and extend an early advance from a British ice source, a maximum period likely dominated by large ice streams, fragmentation of the ice sheet into separate ice bodies during retreat, and final decay in western mountain groups. The pattern of ice sheet evolution is both asymmetric and asynchronous. A range of scales of ice sheet behaviour are observed, from first-order, fundamental changes in ice sheet geometry (centres of mass and ice flow structure) to more local-scale high-frequency fluctuations of ice flow patterns. This new model acts as a framework for continued investigation of the evolution of the Irish Ice Sheet, and the observed ice sheet behaviour demands further exploration of the sensitivities and role of ice sheets in the wider ice - climate system

Seabed corrugations beneath an Antarctic ice shelf revealed by autonomous underwater vehicle survey: Origin and implications for the history of Pine Island Glacier

Ice shelves are critical features in the debate about West Antarctic ice sheet change and sea level rise, both because they limit ice discharge and because they are sensitive to change in the surrounding ocean. The Pine Island Glacier ice shelf has been thinning rapidly since at least the early 1990s, which has caused its trunk to accelerate and retreat. Although the ice shelf front has remained stable for the past six decades, past periods of ice shelf collapse have been inferred from relict seabed "corrugations" (corrugated ridges), preserved 340 km from the glacier in Pine Island Trough. Here we present high-resolution bathymetry gathered by an autonomous underwater vehicle operating beneath an Antarctic ice shelf, which provides evidence of long-term change in Pine Island Glacier. Corrugations and ploughmarks on a sub-ice shelf ridge that was a former grounding line closely resemble those observed offshore, interpreted previously as the result of iceberg grounding. The same interpretation here would indicate a significantly reduced ice shelf extent within the last 11 kyr, implying Holocene glacier retreat beyond present limits, or a past tidewater glacier regime different from today. The alternative, that corrugations were not formed in open water, would question ice shelf collapse events interpreted from the geological record, revealing detail of another bed-shaping process occurring at glacier margins. We assess hypotheses for corrugation formation and suggest periodic grounding of ice shelf keels during glacier unpinning as a viable origin. This interpretation requires neither loss of the ice shelf nor glacier retreat and is consistent with a "stable" grounding-line configuration throughout the Holocene

Advances in understanding subglacial meltwater drainage from past ice sheets

Meltwater drainage beneath ice sheets is a fundamental consideration for understanding ice–bed conditions and bed-modulated ice flow, with potential impacts on terminus behavior and iceshelf mass balance. While contemporary observations reveal the presence of basal water movement in the subglacial environment and inferred styles of drainage, the geological record of former ice sheets, including sediments and landforms on land and the seafloor, aids in understanding the spatiotemporal evolution of efficient and inefficient drainage systems and their impact on ice-sheet behavior. We highlight the past decade of advances in geological studies that focus on providing process-based information on subglacial hydrology of ice sheets, how these studies inform theory, numerical models and contemporary observations, and address the needs for future research

Impairment of perceptual metacognitive accuracy and reduced prefrontal grey matter volume in first-episode psychosis

Introduction: Metacognition, or “thinking about thinking”, is a higher-order thought process that allows for the evaluation of perceptual processes for accuracy. Metacognitive accuracy is associated with the grey matter volume (GMV) in the prefrontal cortex (PFC), an area also impacted in schizophrenia. The present study set out to investigate whether deficits in metacognitive accuracy are present in the early stages of psychosis. Methods: Metacognitive accuracy in first-episode psychosis (FEP) was assessed on a perceptual decision making task and their performance compared to matched healthy control participants (N = 18). A novel signal detection theory approach was used to model metacognitive sensitivity independently from objective perceptual performance. A voxel-based morphometry investigation was also conducted on GMV. Results: We found that the FEP group demonstrated significantly worse metacognitive accuracy compared to controls (p = .039). Importantly, GMV deficits were also observed in the superior frontal gyrus. The findings suggest a specific deficit in this processing domain to exist at first episode; however, no relationship was found between GMV and metacognitive accuracy. Conclusions: Our findings support the notion that an inability to accurately scrutinise perception may underpin functional deficits observed in later schizophrenia; however, the exact neural basis of metacognitive deficits in FEP remains elusive

Hässeldala – a key site for Last Termination climate events in northern Europe

The Last Termination (19 000–11 000 a BP) with its rapid and distinct climate shifts provides a perfect laboratory to study the nature and regional impact of climate variability. The sedimentary succession from the ancient lake at Hässeldala Port in southern Sweden with its distinct Lateglacial/early Holocene stratigraphy (>14.1–9.5 cal. ka BP) is one of the few chronologically well‐constrained, multi‐proxy sites in Europe that capture a variety of local and regional climatic and environmental signals. Here we present Hässeldala's multi‐proxy records (lithology, geochemistry, pollen, diatoms, chironomids, biomarkers, hydrogen isotopes) in a refined age model and place the observed changes in lake status, catchment vegetation, summer temperatures and hydroclimate in a wider regional context. Reconstructed mean July temperatures increased between c. 14.1 and c. 13.1 cal. ka BP and subsequently declined. This latter cooling coincided with drier hydroclimatic conditions that were probably associated with a freshening of the Nordic Seas and started a few hundred years before the onset of Greenland Stadial 1 (c. 12.9 cal. ka BP). Our proxies suggest a further shift towards colder and drier conditions as late as c. 12.7 cal. ka BP, which was followed by the establishment of a stadial climate regime (c. 12.5–11.8 cal. ka BP). The onset of warmer and wetter conditions preceded the Holocene warming over Greenland by c. 200 years. Hässeldala's proxies thus highlight the complexity of environmental and hydrological responses across abrupt climate transitions in northern Europe

Influence of acute fasting on pain tolerance in healthy subjects: a randomised crossover study

BackgroundAlthough chronic pain and obesity are global health crises with substantial healthcare costs, little is known about the relationship between pain perception and eating behaviours. Food consumption has been reported to provide an analgesic effect by the release of neurotransmitters modulating the pain network. However, whether short-term (acute) fasting affects pain perception remains unclear.PurposeThis study aimed to investigate the effect of acute fasting on pain perception and whether attention and mood changes drove the observed changes.Patients and methodsThe cold pressor test (CPT) was used to investigate the pain tolerance of 25 healthy participants in both non-fasting and 12-h fasting sessions. They were randomised to either session with a crossover to the other after at least 24 h, with the experimenter blinded to the sessions. The pain tolerance was measured using a Stroop task in both attentive and distracted states. The Profile of Mood States (POMS) questionnaire was used to capture the mood, and a 10-point hunger scale was used to measure hunger. Mixed-effects models were used to investigate the influence of fasting and distraction on pain perception, accounting for the repeated measures.ResultsFasting reduced CPT pain tolerance, with fasting participants twice as likely to withdraw their hands early (hazard ratio = 2.4, 95% CI: 1.3–4.5). Though men tolerated CPT pain longer than women, there was no evidence that men responded to fasting differently than women (p = 0.9). In addition, no evidence supporting that fasting affected attention or mood was found. Nonetheless, it increased hunger scores by 2.7 points on a 10-point scale (95% CI: 1.2–4.2) and decreased blood glucose concentration levels by 0.51 mmol/L (95% CI: 0.19–0.84).ConclusionAcute fasting reduces pain tolerance in the healthy participants, and this effect is independent of gender and attention or mood changes

Advances in understanding subglacial meltwater drainage from past ice sheets

Meltwater drainage beneath ice sheets is a fundamental consideration for understanding ice–bed conditions and bed-modulated ice flow, with potential impacts on terminus behavior and ice-shelf mass balance. While contemporary observations reveal the presence of basal water movement in the subglacial environment and inferred styles of drainage, the geological record of former ice sheets, including sediments and landforms on land and the seafloor, aids in understanding the spatiotemporal evolution of efficient and inefficient drainage systems and their impact on ice-sheet behavior. We highlight the past decade of advances in geological studies that focus on providing process-based information on subglacial hydrology of ice sheets, how these studies inform theory, numerical models and contemporary observations, and address the needs for future research

Higher Tetanus Toxoid Immunity 2 Years After PsA-TT Introduction in Mali.

BACKGROUND: In 2010, mass vaccination with a then-new meningococcal A polysaccharide-tetanus toxoid protein conjugate vaccine (PsA-TT, or MenAfriVac) was undertaken in 1- to 29-year-olds in Bamako, Mali. Whether vaccination with PsA-TT effectively boosts tetanus immunity in a population with heterogeneous baseline tetanus immunity is not known. We assessed the impact of PsA-TT on tetanus toxoid (TT) immunity by quantifying age- and sex-specific immunity prior to and 2 years after introduction. METHODS: Using a household-based, age-stratified design, we randomly selected participants for a prevaccination serological survey in 2010 and a postvaccination survey in 2012. TT immunoglobulin G (IgG) antibodies were quantified and geometric mean concentrations (GMCs) pre- and postvaccination among all age groups targeted for vaccination were compared. The probability of TT IgG levels ≥0.1 IU/mL (indicating short-term protection) and ≥1.0 IU/mL (indicating long-term protection) by age and sex was determined using logistic regression models. RESULTS: Analysis of 793 prevaccination and 800 postvaccination sera indicated that while GMCs were low pre-PsA-TT, significantly higher GMCs in all age-sex strata were observed 2 years after PsA-TT introduction. The percentage with short-term immunity increased from 57.1% to 88.4% (31.3-point increase; 95% confidence interval [CI], 26.6-36.0;, P < .0001) and with long-term immunity increased from 20.0% to 58.5% (38.5-point increase; 95% CI, 33.7-43.3; P < .0001) pre- and postvaccination. CONCLUSIONS: Significantly higher TT immunity was observed among vaccine-targeted age groups up to 2 years after Mali's PsA-TT mass vaccination campaign. Our results, combined with evidence from clinical trials, strongly suggest that conjugate vaccines containing TT such as PsA-TT should be considered bivalent vaccines because of their ability to boost tetanus immunity

Carbon on the Northwest European Shelf: Contemporary Budget and Future Influences

A carbon budget for the northwest European continental shelf seas (NWES) was synthesized using available estimates for coastal, pelagic and benthic carbon stocks and flows. Key uncertainties were identified and the effect of future impacts on the carbon budget were assessed. The water of the shelf seas contains between 210 and 230 Tmol of carbon and absorbs between 1.3 and 3.3 Tmol from the atmosphere annually. Off-shelf transport and burial in the sediments account for 60–100 and 0–40% of carbon outputs from the NWES, respectively. Both of these fluxes remain poorly constrained by observations and resolving their magnitudes and relative importance is a key research priority. Pelagic and benthic carbon stocks are dominated by inorganic carbon. Shelf sediments contain the largest stock of carbon, with between 520 and 1600 Tmol stored in the top 0.1 m of the sea bed. Coastal habitats such as salt marshes and mud flats contain large amounts of carbon per unit area but their total carbon stocks are small compared to pelagic and benthic stocks due to their smaller spatial extent. The large pelagic stock of carbon will continue to increase due to the rising concentration of atmospheric CO2, with associated pH decrease. Pelagic carbon stocks and flows are also likely to be significantly affected by increasing acidity and temperature, and circulation changes but the net impact is uncertain. Benthic carbon stocks will be affected by increasing temperature and acidity, and decreasing oxygen concentrations, although the net impact of these interrelated changes on carbon stocks is uncertain and a major knowledge gap. The impact of bottom trawling on benthic carbon stocks is unique amongst the impacts we consider in that it is widespread and also directly manageable, although its net effect on the carbon budget is uncertain. Coastal habitats are vulnerable to sea level rise and are strongly impacted by management decisions. Local, national and regional actions have the potential to protect or enhance carbon storage, but ultimately global governance, via controls on emissions, has the greatest potential to influence the long-term fate of carbon stocks in the northwestern European continental shelf

The atrial natriuretic peptide (ANP) knockout mouse does not exhibit the phenotypic features of pre-eclampsia or demonstrate fetal growth restriction

The ANP knockout mouse is reported to exhibit pregnancy-associated hypertension, proteinuria and impaired placental trophoblast invasion and spiral artery remodeling, key features of pre-eclampsia (PE). We hypothesized that these mice may provide a relevant model of human PE with associated fetal growth restriction (FGR). Here, we investigated pregnancies of ANP wild type (ANP+/+), heterozygous (ANP+/-) and knockout (ANP−/-) mice. Maternal blood pressure did not differ between genotypes (E12.5, E17.5), and fetal weight (E18.5) was unaffected. Placental weight was greater in ANP−/− versus ANP+/+ mice. Therefore, in our hands, the ANP model does not express phenotypic features of PE with FGR