The processes responsible for freshwater flux from the Antarctic Ice Sheet (AIS), ice‐shelf basal melting and iceberg calving, are generally poorly represented in current Earth System Models (ESMs). ...Here we document the cryosphere configuration of the U.S. Department of Energy's Energy Exascale Earth System Model (E3SM) v1.2. This includes simulating Antarctic ice‐shelf basal melting, which has been implemented through simulating the ocean circulation within static Antarctic ice‐shelf cavities, allowing for the ability to calculate ice‐shelf basal melt rates from the associated heat and freshwater fluxes. In addition, we added the capability to prescribe forcing from iceberg melt, allowing for realistic representation of the other dominant mass loss process from the AIS. In standard resolution simulations (using a noneddying ocean) under preindustrial climate forcing, we find high sensitivity of modeled ocean/ice shelf interactions to the ocean state, which can result in a transition to a high basal melt regime under the Filchner‐Ronne Ice Shelf (FRIS), presenting a significant challenge to representing the ocean/ice shelf system in a coupled ESM. We show that inclusion of a spatially dependent parameterization of eddy‐induced transport reduces biases in water mass properties on the Antarctic continental shelf. With these improvements, E3SM produces realistic ice‐shelf basal melt rates across the continent that are generally within the range inferred from observations. The accurate representation of ice‐shelf basal melting within a coupled ESM is an important step toward reducing uncertainties in projections of the Antarctic response to climate change and Antarctica's contribution to global sea‐level rise.
Plain Language Summary
The future of the Antarctic Ice Sheet (AIS) has the potential to have broad impacts on global climate, perhaps most notably in contributing to sea‐level rise. The current generation of Earth System Models (ESMs) do not accurately represent the two primary means in which ice is lost from the AIS, through melting at the base of ice shelves floating on the ocean and the calving of icebergs. This limits our ability to make climate projections that incorporate the impacts of the AIS in a changing climate. Here, we demonstrate a novel capability to model one of those processes, ice‐shelf basal melting, in an ESM. We demonstrate the ability to simulate ice‐shelf basal melt rates across many Antarctic ice shelves that are in line with present day observations. We also find that, for certain ice shelves, modeled ice‐shelf basal melting can experience a rapid transition to high melting far above present‐day estimates, and this simulated high melting can be mitigated through improved ocean physics.
Key Points
Capabilities have been added to an Earth System Model to model realistic Antarctic ice‐shelf basal melt fluxes and prescribe iceberg forcing
Simulated basal melt rates have a strong sensitivity to the ocean mesoscale eddy parameterization
For one choice of the mesoscale eddy parameterization, the Filchner‐Ronne Ice Shelf transitions to a high melt regime
SARS-CoV-2 RNA in wastewater settled solids is associated with COVID-19 incidence in sewersheds and therefore, there is a strong interest in using these measurements to augment traditional disease ...surveillance methods. A wastewater surveillance program should provide rapid turn around for sample measurements (ideally within 24 hours), but storage of samples is necessary for a variety of reasons including biobanking. Here we investigate how storage of wastewater solids at 4 °C, -20 °C, and -80 °C affects measured concentrations of SARS-CoV-2 RNA. We find that short term (7 or 8 d) storage of raw solids at 4 °C has little effect on measured concentrations of SARS-CoV-2 RNA, whereas longer term storage at 4 °C (35-122 d) or freezing reduces measurements by 60%, on average. We show that normalizing SARS-CoV-2 RNA concentrations by concentrations of pepper mild mottle virus (PMMoV) RNA, an endogenous wastewater virus, can correct for changes during storage as storage can have a similar effect on PMMoV RNA as on SARS-CoV-2 RNA. The reductions in SARS-CoV-2 RNA in solids during freeze thaws is less than those reported for the same target in liquid influent by several authors.
How does one find objects in scenes? For decades, visual search models have been built on experiments in which observers search for targets, presented among distractor items, isolated and randomly ...arranged on blank backgrounds. Are these models relevant to search in continuous scenes? This article argues that the mechanisms that govern artificial, laboratory search tasks do play a role in visual search in scenes. However, scene-based information is used to guide search in ways that had no place in earlier models. Search in scenes might be best explained by a dual-path model: a ‘selective’ path in which candidate objects must be individually selected for recognition and a ‘nonselective’ path in which information can be extracted from global and/or statistical information.
In the wake of the COVID-19 pandemic, psychologists were pushed to look beyond traditional in-person models of neurodevelopmental assessment to maintain continuity of care. A wealth of data ...demonstrates that telehealth is efficacious for pediatric behavioral intervention; however, best practices for incorporating telehealth into neurodevelopmental assessment are yet to be developed. In this topical review, we propose a conceptual model to demonstrate how telehealth can be incorporated into various components of neurodevelopmental assessment.
Harnessing existing literature and expertise from a multidisciplinary task force comprised of clinicians, researchers, and patient/parent representatives from the subspecialty of cardiac neurodevelopmental care, a conceptual framework for telehealth neurodevelopmental assessment was developed. Considerations for health equity and access to care are discussed, as well as general guidelines for clinical implementation and gaps in existing literature.
There are opportunities to integrate telehealth within each stage of neurodevelopmental assessment, from intake to testing, through to follow-up care. Further research is needed to determine whether telehealth mitigates or exacerbates disparities in access to care for vulnerable populations as well as to provide evidence of validity for a wider range of neurodevelopmental measures to be administered via telehealth.
While many practices are returning to traditional, face-to-face neurodevelopmental assessment services, psychologists have a unique opportunity to harness the momentum for telehealth care initiated during the pandemic to optimize the use of clinical resources, broaden service delivery, and increase access to care for pediatric neurodevelopmental assessment.
Concurrent gemcitabine and nab-paclitaxel treatment is one of the preferred chemotherapy regimens for metastatic and locally advanced pancreatic ductal adenocarcinoma (PDAC). Previous studies ...demonstrate that caveolin-1 (Cav-1) expression is critical for nab-paclitaxel uptake into tumors and correlates with response. Gemcitabine increases nab-paclitaxel uptake by increasing Cav-1 expression. Thus, we hypothesized that pretreatment with gemcitabine would further enhance the sensitivity of PDAC to nab-paclitaxel by increasing Cav-1 expression and nab-paclitaxel uptake.
We investigated the sensitivity of different gemcitabine and nab-paclitaxel treatment regimens in a panel of PDAC cell lines and orthotopic xenograft models. The sensitivity of different treatment regimens was compared with the standard concurrent treatment.
Pretreatment with gemcitabine before nab-paclitaxel increased Cav-1 and albumin uptake and significantly decreased proliferation and clonogenicity compared with concurrent treatment, which correlated with increased levels of apoptosis. Cav-1 silencing reduced the uptake of albumin, and therapeutic advantage was observed when cells were pretreated with gemcitabine prior to nab-paclitaxel. In addition, we observed that pretreatment with gemcitabine resulted in partial synchronization of cells in the G
-M-phase at the time of nab-paclitaxel treatment, providing another mechanism for the benefit of altered scheduling. In heterotopic and orthotopic xenograft models, the altered schedule of gemcitabine prior to nab-paclitaxel significantly delayed tumor growth compared with concurrent delivery without added toxicity.
Pretreatment with gemcitabine significantly increased nab-paclitaxel uptake and correlated with an increased treatment efficacy and survival benefit in preclinical models, compared with standard concurrent treatment. These results justify preclinical and clinical testing of this altered scheduling combination.
Gold mining operations near Yellowknife (Northwest Territories, Canada) released vast quantities of arsenic trioxide during the 1950s, which dispersed across the landscape. Contemporary measurements ...of arsenic concentrations in lake water and surficial sediment identify enrichment within a 30 km radius. However, paleolimnological studies have identified possible evidence of mining influence during the 1950s at a lake beyond this distance, suggesting a more expansive legacy footprint may exist. Here, we analyze spatiotemporal patterns of arsenic, antimony, and lead deposition from sediment cores at lakes located 10–40 km (near-field) and 50–80 km (far-field) from the mines along the prevailing northwesterly wind direction (NW) and 20–40 km to the northeast (NE) of the mines to improve characterization of the legacy footprint of emissions. We build upon previous findings to determine if: 1) there is evidence of mine-related pollutants beyond the well-established 30 km radius and 2) enrichment is greatest in the prevailing wind direction, as expected for aerial dispersion from a point source of emissions. Results demonstrate enrichment since the 1950s for arsenic and antimony at least as far as 80 km to the NW and 40 km to the NE, thus legacy deposition extended beyond the currently defined 30 km radius ‘zone of immediate influence’. Concentrations, enrichment factors, and total excess inventories of arsenic and antimony decline with distance from the mines and are greater along the prevailing (NW) than orthogonal (NE) wind direction. Peak concentrations in uppermost sediment strata at near-field lakes in the prevailing wind direction suggest supply of arsenic and antimony remains high from legacy stores in the catchment and lake sediment profiles >60 years after emissions were released. Such lasting influence of legacy emissions likely is not limited to mines in the Yellowknife region, and paleolimnological approaches can effectively delineate zones of past and ongoing pollution from legacy sources elsewhere.
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•We analyze metals in sediment cores to track dispersal of legacy mine emissions.•Enrichment of As and Sb evident beyond known 30-km radius pollution zone.•Distance from source and wind direction influenced contaminant dispersal.•Enriched surface sediments within 30 km suggest ongoing delivery of legacy metals.
Synaptic inhibition is critical for controlling neuronal excitability and function. During global cerebral ischemia (GCI), inhibitory synapses are rapidly eliminated, causing hyper-excitability which ...contributes to cell-death and the pathophysiology of disease. Sequential disassembly of inhibitory synapses begins within minutes of ischemia onset: GABAARs are rapidly trafficked away from the synapse, the gephyrin scaffold is removed, followed by loss of the presynaptic terminal. GABAARs are endocytosed during GCI, but how this process accompanies synapse disassembly remains unclear. Here, we define the precise trafficking itinerary of GABAARs during the initial stages of GCI, placing them in the context of rapid synapse elimination. Ischemia-induced GABAAR internalization quickly follows their initial dispersal from the synapse, and is controlled by PP1α signaling. During reperfusion injury, GABAARs are then trafficked to lysosomes for degradation, leading to permanent removal of synaptic GABAARs and contributing to the profound reduction in synaptic inhibition observed hours following ischemia onset.
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•Global ischemia initiates a sequential trafficking itinerary for GABAARs•GABAARs are dispersed from synapses and PP1α activity drives their surface removal•During reperfusion, GABAARs are sorted to lysosomes for degradation•Together, these steps underly persistent loss of GABAARs from synapses in ischemia
Cellular neuroscience; Molecular physiology
We developed a method to automatically assess texts for features that help readers produce gist inferences. Following fuzzy-trace theory, we used a procedure in which participants recalled events ...under gist or verbatim instructions. Applying Coh-Metrix, we analyzed written responses in order to create gist inference scores (GISs), or seven variables converted to Z scores and averaged, which assess the potential for readers to form gist inferences from observable text characteristics. Coh-Metrix measures reflect referential cohesion and deep cohesion, which increase GIS because they facilitate coherent mental representations. Conversely, word concreteness, hypernymy for nouns and verbs (specificity), and imageability decrease GIS, because they promote verbatim representations. Also, the difference between abstract verb overlap among sentences (using latent semantic analysis) and more concrete verb overlap (using WordNet) should enhance coherent gist inferences, rather than verbatim memory for specific verbs. In the first study, gist condition responses scored nearly two standard deviations higher on GIS than did the verbatim condition responses. Predictions based on GIS were confirmed in two text analysis studies of 50 scientific journal article texts and 50 news articles and editorials. Texts from the
Discussion
sections of psychology journal articles scored significantly higher on GIS than did texts from the
Method
sections of the same journal articles. News reports also scored significantly lower than editorials on the same topics from the same news outlets. GIS proved better at discriminating among texts than did alternative formulae. In a behavioral experiment with closely matched text pairs, people randomly assigned to high-GIS versions scored significantly higher on knowledge and comprehension.
Abstract Objective: To identify ethnic differences in the incidence of first ever stroke. Design: A prospective community stroke register (1995-6) with multiple notification sources. Pathological ...classification of stroke in all cases was based on brain imaging or necropsy data. Rates were standardised to European and world populations and adjusted for age, sex, and social class in multivariate analysis. Setting: A multi-ethnic population of 234 533 in south London, of whom 21% are black. Results:612 strokes were registered. The crude annual incidence rate was 1.3 strokes per 1000 population per year (95% confidence interval 1.20 to 1.41) and 1.25 per 1000 population per year(1.15 to 1.35) age adjusted to the standard European population. Incidence rates adjusted for age and sex were significantly higher in black compared with white people (P<0.0001), with an incidence rate ratio of 2.21 (1.77 to 2.76). In multivariable analysis increasing age(P<0.0001), male sex (P<0.003), black ethnic group (P<0.0001), and lower social class (P<0.0001) in people aged 35-64 were independently associated with an increased incidence of stroke. Conclusions:Incidence rates of stroke are higher in the black population; this is not explained by confounders such as social class, age, and sex. Ethnic differences in genetic, physiological, and behavioural risk factors for stroke require further elucidation to aid development of effective strategies for stroke prevention in multi-ethnic communities.
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