The global population and status of Snowy Owls Bubo scandiacus are particularly challenging to assess because individuals are irruptive and nomadic, and the breeding range is restricted to the remote circumpolar Arctic tundra. The International Union for Conservation of Nature (IUCN) uplisted the Snowy Owl to “Vulnerable” in 2017 because the suggested population estimates appeared considerably lower than historical estimates, and it recommended actions to clarify the population size, structure, and trends. Here we present a broad review and status assessment, an effort led by the International Snowy Owl Working Group (ISOWG) and researchers from around the world, to estimate population trends and the current global status of the Snowy Owl. We use long-term breeding data, genetic studies, satellite-GPS tracking, and survival estimates to assess current population trends at several monitoring sites in the Arctic and we review the ecology and threats throughout the Snowy Owl range. An assessment of the available data suggests that current estimates of a worldwide population of 14,000–28,000 breeding adults are plausible. Our assessment of population trends at five long-term monitoring sites suggests that breeding populations of Snowy Owls in the Arctic have decreased by more than 30% over the past three generations and the species should continue to be categorised as Vulnerable under the IUCN Red List Criterion A2. We offer research recommendations to improve our understanding of Snowy Owl biology and future population assessments in a changing world.

Secondary minerals formed during simulated weathering of nuclear waste glasses have been identified by analytical electron microscopy. A complete description of the reacted glass, from the outermost surface in direct contact with the leachant solution to the reacting front that migrates into the bulk glass, was obtained. Manganese and iron oxyhydroxide phases and saponite were found to have precipitated onto the residual glass surface from the leachant solution. Iron-bearing smectite, serpentine, and manganese and uranium-titanium oxyhydroxides formed in situ in the glass in several distinct bands at different depths beneath the original surface. This sequential development of secondary phases displays a clear trend toward more order and crystallinity in the phases farthest from the reaction front and indicates that complete restructuring of the glass into crystalline phases did not occur at the interface with fresh glass. Additionally, the formation of a discrete uranium-bearing phase, as opposed to uranium uptake by precipitated phases, suggests that stable actinide phase formation rather than ion exchange may be a possible mechanism for retarding radionuclide release to the environment.

Introduction: Epidemiologic and modeling studies suggest that between 45 and 70% of individuals with chronic hepatitis C virus (HCV) infection in Canada remain undiagnosed. The Canadian Association for the Study of the Liver (CASL) recommends one-time screening of baby boomers (1945-1975). Screening programs in the US have shown a very high prevalence of previously undiagnosed HCV among patients seen in the emergency department (ED). We sought to assess the feasibility of implementing a targeted birth-cohort HCV screening program in a Canadian ED setting. Methods: Patients born from 1945 to 1975 presenting to the ED of a downtown Toronto hospital were offered HCV testing. Patients with life-threatening conditions, unable to provide verbal consent in English or intoxication were excluded. Blood samples were collected by finger prick on Dried Blood Spot (DBS) collection cards and tested for anti-HCV antibody with reflex to HCV RNA. Patients with positive HCV RNA were referred to a liver specialist. Results: During a 27-month period (July 2017 - Sept 2019), 8363 patients in the birth cohort presented to the ED during daytime hours. 80% (6714) met eligibility criteria, and 48.4% (3247) were offered testing. Screening was performed by non-medical staff (mean 8/day, median spots on DBS 4). 345 (10.6%) had been previously tested, and 639 (19.7%) declined. 2136 (65.8%) patients underwent testing: median age 58.4 years (40-82), 1117 male (52.3%). Of these, 45 patients (2.1%; 95% CI 1.5%-2.7%) were anti-HCV positive: 32 (76.2%) were HCV RNA positive, 10 (23.8%) negative and 3 not done due to inadequate DBS sample. 26 patients (81.3%) were linked to care and 3 (9.4%) lost to follow-up. HCV prevalence in the ED was significantly higher than the general Canadian population (2.1% vs 0.7%; p < 0.0001) but much lower than reported rates in American EDs (2.1% vs 10.3%; p < 0.0001). Conclusion: Acceptance of HCV screening in the ED birth cohort was high and easily performed using DBS to ensure the majority of positive samples were tested for HCV RNA. Challenges included implementation that limited number of people tested, and linkage to care for HCV positive patients. HCV prevalence among this ED birth cohort was higher than the general population but lower than seen in the ED in the US. This may in part be due to exclusion of individuals with more severe medical issues, refusal by higher risk subgroups, or population and healthcare system differences between countries.

We investigate whether musculoskeletal anatomy and three-dimensional (3-D) body proportions were modified during the evolution of large (>6000 kg) body size in Allosauroidea (Dinosauria: Theropoda). Three adaptations for maintaining locomotor performance at large body size, related to muscle leverage, mass, and body proportions, are tested and all are unsupported in this analysis. Predictions from 3-D musculoskeletal models of medium-sized (Allosaurus) and large-bodied (Acrocanthosaurus) allosauroids suggest that muscle leverage scaled close to isometry, well below the positive allometry required to compensate for declining muscle cross-sectional area with increasing body size. Regression analyses on a larger allosauroid data set finds slight positive allometry in the moment arms of major hip extensors, but isometry is included within confidence limits. Contrary to other recent studies of large-bodied theropod clades, we found no compelling evidence for significant positive allometry in muscle mass between exemplar medium- and large-bodied allosauroids. Indeed, despite the uncertainty in quantitative soft tissue reconstruction, we find strong evidence for negative allometry in the caudofemoralis longus muscle, the single largest hip extensor in non-avian theropods. Finally, we found significant inter-study variability in center-of-mass predictions for allosauroids, but overall observe that consistently proportioned soft tissue reconstructions produced similar predictions across the group, providing no support for a caudal shift in the center of mass in larger taxa that might otherwise reduce demands on hip extensor muscles during stance. Our data set provides further quantitative support to studies that argue for a significant decline in locomotor performance with increasing body size in non-avian theropods. However, although key pelvic limb synapomorphies of derived allosauroids (e.g., dorsomedially inclined femoral head) evolved at intermediate body sizes, they may nonetheless have improved mass support.

The crustose lichen Lecanora conizaeoides has declined markedly around London with progressively diminishing sulphur dioxide pollution of the air since the 1960s. To identify the immediate causes of its decline, we applied S in the form of bisulphite (0·2 & 2 mM) and sulphate (2 mM), and N as nitrate (2 mM) to relict colonies of the lichen on beech trunks in a plantation in Windsor Forest. Growth of the lichen was monitored by estimating changes in percentage cover. By the end of a 25-month period of two-weekly treatments, all the chemical treatments had resulted in significant decreases in cover of L. conizaeoides compared to distilled water controls, with the 2 mM bisulphite causing the greatest loss. Bark surface pH was also lowered by the chemical treatments, but most by the 2 mM bisulphite applications. Similar results were obtained in two laboratory experiments where the nutrient applications were repeated under a controlled environment and thallus area monitored photographically. No evidence was obtained to support the hypothesis that growth of L. conizaeoides is stimulated by an elevated sulphur supply. We conclude that the disappearance of the lichen is linked to gradual increase in bark pH caused by the combined effects of a marked reduction in SO2 emissions and rising emissions of NH3.

Isoenzyme-based studies have identified 3 taxa/species/‘phylogenetic complexes’ as agents of visceral leishmaniasis in Sudan: L. donovani, L. infantum and “L. archibaldi”. However, these observations remain controversial. A new chitinase gene phylogeny was constructed in which stocks of all 3 putative species isolated in Sudan formed a monophyletic clade. In order to construct a more robust classification of the L. donovani complex, a panel of 16 microsatellite markers was used to describe 39 stocks of these 3 species. All “L. donovani complex” stocks from Sudan were again found to form a single monophyletic clade. L. donovani ss stocks from India and Kenya were found to form 2 region-specific clades. The partial sequence of the glutamate oxaloacetate transaminase (GOT) gene of 17 L. donovani complex stocks was obtained. A single nucleotide polymorphism in the GOT gene appeared to underlie the isoenzyme classification. It was concluded that isoenzyme-based identification is unsafe for stocks isolated in L. donovani endemic areas and identified as L. infantum. It was also concluded that the name L. archibaldi is invalid and that only a single visceralizing species, Leishmania donovani, is found in East Africa.