Glacial history of the Åsgardfonna Ice Cap, NE Spitsbergen, since the last glaciation

The response of glaciers and ice caps to past climate change provides important insight into how they will react to ongoing and future global warming. In Svalbard, the Holocene glacial history has been studied for many cirque and valley glaciers. However, little is known about how the larger ice caps in Svalbard responded to Late Glacial and Holocene climate changes. Here we use lake sediment cores and geophysical data from Femmilsjøen, one of Svalbard’s largest lakes, to reconstruct the glacial history of the Åsgardfonna Ice Cap since the last deglaciation. We find that Femmilsjøen potentially deglaciated prior to 16.1 ± 0.3 cal ka BP and became isolated from the marine environment between 11.7 ± 0.3 to 11.3 ± 0.2 cal ka BP. Glacial meltwater runoff was absent between 10.1 ± 0.4 and 3.2 ± 0.2 cal ka BP, indicating that Åsgardfonna was greatly reduced or disappeared in the Early and Middle Holocene. Deposition of glacial-meltwater sediments re-commenced in Femmilsjøen at c. 3.2 ± 0.2 cal ka BP, indicating glacier re-growth in the Femmilsjøen catchment and the onset of the Neoglacial. The glacier(s) in the Femmilsjøen catchment area reached sizes no smaller than their modern extents already at c. 2.1 ± 0.7 cal ka BP. Our results suggest that larger Svalbard ice caps such as Åsgardfonna are very sensitive to climate changes and probably melted completely during the Holocene Thermal Maximum. Such information can be used as important constraints in future ice-cap simulations

A divergent heritage for complex organics in Isheyevo lithic clasts

Primitive meteorites are samples of asteroidal bodies that contain a high proportion of chemically complex organic matter (COM) including prebiotic molecules such as amino acids, which are thought to have been delivered to Earth via impacts during the early history of the Solar System. Thus, understanding the origin of COM, including their formation pathway(s) and environment(s), is critical to elucidate the origin of life on Earth as well as assessing the potential habitability of exoplanetary systems. The Isheyevo CH/CBb carbonaceous chondrite contains chondritic lithic clasts with variable enrichments in 15N believed to be of outer Solar System origin. Using transmission electron microscopy (TEM-EELS) and in situ isotope analyses (SIMS and NanoSIMS), we report on the structure of the organic matter as well as the bulk H and N isotope composition of Isheyevo lithic clasts. These data are complemented by electron microprobe analyses of the clast mineral chemistry and bulk Mg and Cr isotopes obtained by inductively coupled plasma and thermal ionization mass spectrometry, respectively (MC-ICPMS and TIMS). Weakly hydrated (A) clasts largely consist of Mg-rich anhydrous silicates with local hydrated veins composed of phyllosilicates, magnetite and globular and diffuse organic matter. Extensively hydrated clasts (H) are thoroughly hydrated and contain Fe-sulfides, sometimes clustered with organic matter, as well as magnetite and carbonates embedded in a phyllosilicate matrix. The A-clasts are characterized by a more 15N-rich bulk nitrogen isotope composition (δ15N = 200–650‰) relative to H-clasts (δ15N = 50–180‰) and contain extremely 15N-rich domains with δ15N 15N-rich domains show that the lithic clast diffuse organic matter is typically more 15N-rich than globular organic matter. The correlated δ15N values and C/N ratios of nanoglobules require the existence of multiple organic components, in agreement with the H isotope data. The combined H and N isotope data suggest that the organic precursors of the lithic clasts are defined by an extremely 15N-poor (similar to solar) and D-rich component for H-clasts, and a moderately 15N-rich and D-rich component for A-clasts. In contrast, the composition of the putative fluids is inferred to include D-poor but moderately to extremely 15N-rich H- and N-bearing components. The variable 15N enrichments in H- and A-clasts are associated with structural differences in the N bonding environments of their diffuse organic matter, which are dominated by amine groups in H-clasts and nitrile functional groups in A-clasts. We suggest that the isotopically divergent organic precursors in Isheyevo clasts may be similar to organic moieties in carbonaceous chondrites (CI, CM, CR) and thermally recalcitrant organic compounds in ordinary chondrites, respectively. The altering fluids, which are inferred to cause the 15N enrichments observed in the clasts, may be the result of accretion of variable abundances of NH3 and HCN ices. Finally, using bulk Mg and Cr isotope composition of clasts, we speculate on the accretion regions of the various primitive chondrites and components and the origin of the Solar System’s N and H isotope variability

Neutrophil Paralysis in Plasmodium vivax Malaria

Plasmodium vivax is responsible for approximately 60–80% of the malaria cases in the world, and contributes to significant social and economic instability in the developing countries of Latin America and Asia. The pathogenesis of P. vivax malaria is a consequence of host derived inflammatory mediators. Hence, a better understanding of the mechanisms involved in induction of systemic inflammation during P. vivax malaria is critical for the clinical management and prevention of severe disease. The innate immune receptors recognize Plasmodium sp. and initiate a broad spectrum of host defense mechanisms that mediate resistance to infection. However, the innate immune response is the classic “two-edged sword”, and clinical malaria is associated with high levels of circulating pro-inflammatory cytokines. Our findings show that both monocytes and neutrophils are highly activated during malaria. Monocytes produced high levels of IL-1β, IL-6 and TNF-α during acute malaria. On the other hand, neutrophils were a poor source of cytokines, but displayed an enhanced phagocytic activity and superoxide production. Unexpectedly, we noticed an impaired chemotaxis of neutrophils towards an IL-8 (CXCL8) gradient. We proposed that neutrophil paralysis is in part responsible for the enhanced susceptibility to bacterial infection observed in malaria patients

Persistence of Holocene ice cap in northeast Svalbard aided by glacio-isostatic rebound

The deglaciation of the Svalbard-Barents Sea Ice Sheet was driven by relative sea-level rise, the incursion of North Atlantic waters around Spitsbergen, and increasing summer insolation. However, ice retreat was inter rupted by asynchronous re-advances that occurred into high relative seas, during a period associated with warm regional waters and elevated summer temperatures. Better understanding of this complex style of deglaciation and the dynamic response to a warming climate can serve as an important analogue for modern warming and today’s ice sheets. We present evidence from northern Svalbard of glacier re-advances during the Late Glacial Early Holocene in hand with relative sea-level history and the occurrence of thermophilous molluscs. We argue that glacio-isostatic adjustment during the transition into the Holocene influenced ice marginal dynamics and as a result, the southern region of the Åsgardfonna ice cap persisted through the Holocene Thermal Maximum

Making robust decisions about the impact of health education programs: Psychometric evaluation of the Health Education Impact Questionnaire (heiQ) in diverse patient groups in Norway

OBJECTIVE: To undertake a rigorous psychometric evaluation of the widely used eight-scale heiQ version 2.0 (evaluating immediate effects of self-management interventions) in diverse patient groups in Norway. METHODS: Cross-sectional survey data were collected from 1019 Norwegians. Data were extracted from studies among people with musculoskeletal disorders (n=516), psoriasis (n=254), heart disease (n=97), and Type 2 diabetes (n=152). To investigate the factorial validity of the Norwegian heiQ, confirmatory factor analyses (CFA) were carried out using Mplus. RESULTS: One-factor model fit, without modifications, was acceptable for the Emotional distress scale. Only one correlated residual was required to be fitted in each of the other scales to achieve satisfactory model fit. The postulated highly restricted full eight-factor model (no cross-loadings, no correlated residuals) showed good fit to the data. Internal consistency was acceptable for most scales (0.72-0.90) but low for Self-monitoring and insight. CONCLUSION: This study of the Norwegian heiQ replicates the factor structure of the original Australian heiQ, using robust and highly restricted CFA procedures, demonstrating a clean independent clusters model structure. PRACTICE IMPLICATIONS: Researchers, program implementers and policymakers could use the Norwegian heiQ with confidence to generate reliable information on program outcomes and support quality improvement activities