Advances in modelling subglacial lakes and their interaction with the Antarctic ice sheet

Subglacial lakes have long been considered hydraulically isolated water bodies underneath ice sheets. This view changed radically with the advent of repeat-pass satellite altimetry and the discovery of multiple lake discharges and water infill, associated with water transfer over distances of more than 200 km. The presence of subglacial lakes also influences ice dynamics, leading to glacier acceleration. Furthermore, subglacial melting under the Antarctic ice sheet is more widespread than previously thought, and subglacial melt rates may explain the availability for water storage in subglacial lakes and water transport. Modelling of subglacial water discharge in subglacial lakes essentially follows hydraulics of subglacial channels on a hard bed, where ice sheet surface slope is a major control on triggering subglacial lake discharge. Recent evidence also points to the development of channels in deformable sediment in West Antarctica, with significant water exchanges between till and ice. Most active lakes drain over short time scales and respond rapidly to upstream variations. Several Antarctic subglacial lakes exhibit complex interactions with the ice sheet due to water circulation. Subglacial lakes can therefore—from a modelling point of view—be seen as confined small oceans underneath an imbedded ice shelf.</jats:p

Trust, but verify? Understanding citizen attitudes toward evidence-informed policy making

In this article, we inquire to what extent different manifestations of trust are associated with public support for evidence informed policy making (EIPM). We present the results of a cross-sectional survey conducted in the peak of the second COVID-19 wave in six Western democracies: Australia, Belgium, Canada, France, Switzerland, and the United States (N = 8749). Our findings show that public trust in scientific experts is generally related to positive attitudes toward evidence-informed policy making, while the opposite is the case for trust in governments and fellow citizens. Interestingly, citizens' assessment of government responses to COVID-19 moderates the relationship between trust and attitudes toward EIPM. Respondents who do rather not trust their governments or their fellow citizens are more in favor of EIPM if they evaluate government responses negatively. These findings suggest that attitudes toward EIPM are not only related to trust, but also strongly depend on perceived government performance.The politics and administration of institutional chang

Beleidsevaluatie vandaag: Een voorzichtige balans

The politics and administration of institutional chang

Beleidsevaluatie vandaag: Een voorzichtige balans

The politics and administration of institutional chang

Ice core evidence for a 20th century increase in surface mass balance in coastal Dronning Maud Land, East Antarctica

Ice cores provide temporal records of surface mass balance (SMB). Coastal areas of Antarctica have relatively high and variable SMB, but are under-represented in records spanning more than 100 years. Here we present SMB reconstruction from a 120 m-long ice core drilled in 2012 on the Derwael Ice Rise, coastal Dronning Maud Land, East Antarctica. Water stable isotope (δ18O and δD) stratigraphy is supplemented by discontinuous major ion profiles and continuous electrical conductivity measurements. The base of the ice core is dated to AD 1759 ± 16, providing a climate proxy for the past  ∼ 250 years. The core's annual layer thickness history is combined with its gravimetric density profile to reconstruct the site's SMB history, corrected for the influence of ice deformation. The mean SMB for the core's entire history is 0.47 ± 0.02 m water equivalent (w.e.) a−1. The time series of reconstructed annual SMB shows high variability, but a general increase beginning in the 20th century. This increase is particularly marked during the last 50 years (1962–2011), which yields mean SMB of 0.61 ± 0.01 m w.e. a−1. This trend is compared with other reported SMB data in Antarctica, generally showing a high spatial variability. Output of the fully coupled Community Earth System Model (CESM) suggests that, although atmospheric circulation is the main factor influencing SMB, variability in sea surface temperatures and sea ice cover in the precipitation source region also explain part of the variability in SMB. Local snow redistribution can also influence interannual variability but is unlikely to influence long-term trends significantly. This is the first record from a coastal ice core in East Antarctica to show an increase in SMB beginning in the early 20th century and particularly marked during the last 50 years

Fxyd2 regulates Aδ- and C-fiber mechanosensitivity and is required for the maintenance of neuropathic pain

Identification of the molecular mechanisms governing sensory neuron subtype excitability is a key requisite for the development of treatments for somatic sensory disorders. Here, we show that the Na,K-ATPase modulator Fxyd2 is specifically required for setting the mechanosensitivity of Aδ-fiber low-threshold mechanoreceptors and sub-populations of C-fiber nociceptors, a role consistent with its restricted expression profile in the spinal somatosensory system. We also establish using the spared nerve injury model of neuropathic pain, that loss of Fxyd2 function, either constitutively in Fxyd2(-/-) mice or acutely in neuropathic rats, efficiently alleviates mechanical hypersensitivity induced by peripheral nerve lesions. The role of Fxyd2 in modulating Aδ- and C-fibers mechanosensitivity likely accounts for the anti-allodynic effect of Fxyd2 knockdown. Finally, we uncover the evolutionarily conserved restricted expression pattern of FXYD2 in human dorsal root ganglia, thus identifying this molecule as a potentially promising therapeutic target for peripheral neuropathic pain management

Conservative solutions for progress: on solution types when combining QCA with in-depth Process-Tracing

What is the most appropriate QCA solution type when engaging in a multimethod design that includes QCA and in-depth process-tracing (PT)? While either the intermediate or the parsimonious solution are generally favored in QCA-only studies, we identify important challenges that can emerge when selecting those solutions in a QCA-PT multimethod study. We particularly highlight the risk of mechanistic heterogeneity, omitted conditions, and draw the attention on the issue of generalization. We discuss each of these intertwined challenges in depth, and explain why the conservative solution is useful to consider in addressing them. We substantiate our arguments by drawing on a recently completed evaluation study that was commissioned by the Flemish ESF Agency in Belgium. In the study, we combined QCA and theory-guided in-depth process-tracing to uncover under what combinations of conditions (QCA) a training programme would lead to successful training transfer and how (PT) this happened in the successful cases. The article highlights the need to carefully consider the selection of solution types in any multimethod design comprising QCA.The politics and administration of institutional chang

Neck–size Distributions of Through–pores in Polymer Membranes

AbstractThe capillary flow porometry (CFP) is generally used for measuring the bubble point pressure corresponding to largest through pore–size in the membrane. In present work, the CFP technique was used for developing a methodology for determination of the neck–size distributions in the synthetic membranes. It is important as the transport flux across the membrane is controlled by the neck size of through–pores. Therefore the average, maximum and minimum pore sizes and pore–size distribution in these membranes was determined by CFP and compared with different techniques like Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Molecular Weight Cut–off (MWCO). For the MWCO method, the Stokes radius of solute poly(ethylene oxide) (PEO) was calculated using the method commonly used, and also confirmed by Dynamic Light Scattering (DLS)