Changes in epidemiological patterns of sea lice infestation on farmed Atlantic salmon, Salmo salar L., in Scotland between 1996 and 2006

Analyses of a unique database containing sea lice records over an 11 year period provide evidence of changing infestation patterns in Scotland. The data, collected from more than 50 commercial Atlantic salmon farms, indicate that both species of sea lice commonly found in Scotland, Lepeophtheirus salmonis and Caligus elongatus, have declined on farms over the past decade. Reductions for both species have been particularly marked since 2001 when more effective veterinary medicines became available. Treatment data were also available in the database and these show a growing trend towards the use of the in feed medication emamectin benzoate (Slice), particularly in the first year of the salmon production cycle. However, this trend to wards single product use has not been sustained in 2006, the latest year for which data are available. There is some evidence of region to region variation within Scotland with the Western Isles experiencing higher levels of infestation. However, compared to the levels observed between 1996 and 2000, all regions have benefited from reduced lice infestation, with the overall pattern showing a particular reduction in the second and third quarters of the second year of production

Gender differences in the prevalence of impaired fasting glycaemia and impaired glucose tolerance in Mauritius. Does sex matter?

Objective: To examine gender differences in the characteristics and prevalence of various categories of glucose tolerance in a population study in Mauritius.Research design and methods: In 1998, a community-based cross-sectional survey was conducted in Mauritius. Categories of glucose metabolism were determined in 5388 adults, with an oral glucose tolerance test given to those who did not have previously diagnosed diabetes (n = 4036). Other cardiovascular risk factors were assessed among those without known diabetes.Results: For men and women the prevalence of diabetes (22.0 vs. 21.8%, respectively) and the prevalence of coexisting impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) (3.2 vs. 2.9%) were similar. However, men were twice as likely as women to have isolated IFG [5.1% (4.2&ndash;6.0) vs. 2.9% (2.3&ndash;3.5)], despite being younger, thinner and with lower plasma insulin but higher lipids. Conversely, the prevalence of isolated IGT was lower in men [9.0% (7.9&ndash;10.2) vs. 13.9% (12.6&ndash;15.1)]. Among non-diabetic individuals, fasting glucose was higher in men than women, whereas 2-h glucose was higher in women. In people without diabetes, women had significantly higher body mass index, beta cell function (HOMA-B), fasting and 2-h insulin than men and significantly lower waist-hip ratios, waist circumference, insulin sensitivity (HOMA-S) and triglycerides.Conclusion: In Mauritius, the distribution of impaired glucose metabolism differs by sex. The observation that IFG is more prevalent in men and IGT more prevalent in women raises important questions about their underlying aetiology and the ability of the current glucose thresholds to equally identify men and women at high-risk of developing diabetes. IFG should be seen as a complimentary category of abnormal glucose tolerance, rather than a replacement for IGT.<br /

Raptor research during the COVID-19 pandemic provides invaluable opportunities for conservation biology

Authors acknowledge financial support from: the Dean Amadon Grant of the Raptor Research Foundation (to PS); the Raptor Research and Conservation Foundation, Mumbai, and the University of Oxford's Global Challenges Research Fund through the Ind-Ox initiative (KCD00141-AT13.01) (both to NK), and the Gordon and Betty Moore Foundation (GBMF9881) and the National Geographic Society (NGS-82515R-20) (both to CR).Research is underway around the world to examine how a wide range of animal species have responded to reduced levels of human activity during the COVID-19 pandemic. In this perspective article, we argue that raptors are particularly well-suited for investigating potential ‘anthropause’ effects, and that the resulting insights will provide much-needed impetus for global conservation efforts. Lockdowns likely alter many of the extrinsic factors that normally limit raptor populations. These environmental changes are in turn expected to influence – mediated by behavioral and physiological responses – the intrinsic (demographic) factors that ultimately determine raptor population levels and distributions. Using this framework, we identify a range of research opportunities and conservation challenges that have arisen during the pandemic. The COVID-19 anthropause allows raptor researchers to address fundamental and applied research objectives in a large-scale, quasi-experimental, well-replicated manner. Importantly, it will be possible to separate the effects of human disturbance and anthropogenic landscape modifications. We explain how high-quality datasets, accumulated for a diverse range of raptor species before, during, and after COVID-19 lockdowns, can be leveraged for powerful comparative analyses that attempt to identify drivers of particular response types. To facilitate and coordinate global collaboration, we are hereby launching the ‘Global Anthropause Raptor Research Network’ (GARRN). We invite the international raptor research community to join this inclusive and diverse group, to tackle ambitious analyses across geographic regions, ecosystems, species, and gradients of lockdown perturbation. Under the most tragic of circumstances, the COVID-19 anthropause has afforded an invaluable opportunity to significantly boost global raptor conservation.Publisher PDFPeer reviewe

Population Monte Carlo algorithms

We give a cross-disciplinary survey on ``population'' Monte Carlo algorithms. In these algorithms, a set of ``walkers'' or ``particles'' is used as a representation of a high-dimensional vector. The computation is carried out by a random walk and split/deletion of these objects. The algorithms are developed in various fields in physics and statistical sciences and called by lots of different terms -- ``quantum Monte Carlo'', ``transfer-matrix Monte Carlo'', ``Monte Carlo filter (particle filter)'',``sequential Monte Carlo'' and ``PERM'' etc. Here we discuss them in a coherent framework. We also touch on related algorithms -- genetic algorithms and annealed importance sampling.Comment: Title is changed (Population-based Monte Carlo -> Population Monte Carlo). A number of small but important corrections and additions. References are also added. Original Version is read at 2000 Workshop on Information-Based Induction Sciences (July 17-18, 2000, Syuzenji, Shizuoka, Japan). No figure

Effects of hydrostatic pressure on the magnetic susceptibility of ruthenium oxide Sr3Ru2O7: Evidence for pressure-enhanced antiferromagnetic instability

Hydrostatic pressure effects on the temperature- and magnetic field dependencies of the in-plane and out-of-plane magnetization of the bi-layered perovskite Sr3Ru2O7 have been studied by SQUID magnetometer measurements under a hydrostatic helium-gas pressure. The anomalously enhanced low-temperature value of the paramagnetic susceptibility has been found to systematically decrease with increasing pressure. The effect is accompanied by an increase of the temperature Tmax of a pronounced peak of susceptibility. Thus, magnetization measurements under hydrostatic pressure reveal that the lattice contraction in the structure of Sr3Ru2O7 promotes antiferromagnetism and not ferromagnetism, contrary to the previous beliefs. The effects can be explained by the enhancement of the inter-bi-layer antiferromagnetic spin coupling, driven by the shortening of the superexchange path, and suppression, due to the band-broadening effect, of competing itinerant ferromagnetic correlations.Comment: 11 pages, 4 figure

Consistent Anisotropic Repulsions for Simple Molecules

We extract atom-atom potentials from the effective spherical potentials that suc cessfully model Hugoniot experiments on molecular fluids, e.g., $O_2$ and $N_2$. In the case of $O_2$ the resulting potentials compare very well with the atom-atom potentials used in studies of solid-state propertie s, while for $N_2$ they are considerably softer at short distances. Ground state (T=0K) and room temperatu re calculations performed with the new $N-N$ potential resolve the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure

Force-Extension Relations for Polymers with Sliding Links

Topological entanglements in polymers are mimicked by sliding rings (slip-links) which enforce pair contacts between monomers. We study the force-extension curve for linear polymers in which slip-links create additional loops of variable size. For a single loop in a phantom chain, we obtain exact expressions for the average end-to-end separation: The linear response to a small force is related to the properties of the unstressed chain, while for a large force the polymer backbone can be treated as a sequence of Pincus--de Gennes blobs, the constraint effecting only a single blob. Generalizing this picture, scaling arguments are used to include self-avoiding effects.Comment: 4 pages, 5 figures; accepted to Phys. Rev. E (Brief Report