Convective tipping point initiates localization of basaltic fissure eruptions

Basaltic fissure eruptions may evolve rapidly and unpredictably complicating hazard management. Localization of an elongate fissure to one or more focused vents may take days to months, and depends on fluid dynamic processes, such as thermally-driven viscous fingering, in the sub-volcanic plumbing system. However, fluid dynamics in a dyke geometry are poorly understood. We perform scaled analogue experiments to investigate convective magma exchange flow within a dyke-like conduit, and discover flow regimes ranging from chaotic mingling to stable, well-organized exchange, over the parameter space relevant for natural eruptions. Experiments are scaled via the Grashof number Gr, which is a Reynolds number for buoyancy-driven exchange flows. We propose that chaotic exchange at high Gr hinders thermally-driven localization by suppressing viscous fingering, whereas flow organization at low Gr enhances localization. Consequently, progressive decrease in Gr through increasing magma viscosity or decreasing dyke width pushes a fissure eruption towards a tipping point that results in rapid localization. Our findings indicate that current conceptual models for magma flow in a dyke require revision to account for this convective tipping point, and provide a quantitative framework for understanding the evolution of fissure eruptions

Seagrass science is growing: a report on the 12th International Seagrass Biology Workshop

This conference report describes the programme of the 12th International Seagrass Biology Workshop, its highlights, areas of growth for the workshop, and potential future directions for the workshop series. The report is written with an eye toward where it fits within the field of seagrass research

Food insecurity and subsequent weight gain in women

Objective: Cross-sectional data indicate that a relationship between household food insecurity and overweight exists among women in the USA. Cross-sectional data cannot determine if food insecurity leads to overweight as some have hypothesised. The purpose of the present study was to examine the relationship of food insecurity with subsequent weight gain in women using data from the Panel Study of Income Dynamics (PSID). Design, setting and subjects:Panel data from the 1999 and 2001 PSID, a nationally representative sample of households, were analysed using multivariate regression procedures. Results: Average weight gain among all women (n=5595) was 1.1 kg on average over the two years. There were no significant differences in the percentages of women who gained a clinically significant amount (2.3kg) by food insecurity status. Overweight women who were on a weight-gain trajectory during the 2-year period gained less if they were food-insecure. This relationship was not observed among healthy-weight or obese women. Conclusions: Overall, food insecurity does not appear to be strongly associated with subsequent weight gain in women

Rotary engine cooling system

A rotary engine has a substantially trochoidal-shaped housing cavity in which a rotor planetates. A cooling system for the engine directs coolant along a single series path consisting of series connected groups of passages. Coolant enters near the intake port, passes downwardly and axially through the cooler regions of the engine, then passes upwardly and axially through the hotter regions. By first flowing through the coolest regions, coolant pressure is reduced, thus reducing the saturation temperature of the coolant and thereby enhancing the nucleate boiling heat transfer mechanism which predominates in the high heat flux region of the engine during high power level operation

Phylogenetic relationships of the Wolbachia of nematodes and arthropods

Wolbachia are well known as bacterial symbionts of arthropods, where they are reproductive parasites, but have also been described from nematode hosts, where the symbiotic interaction has features of mutualism. The majority of arthropod Wolbachia belong to clades A and B, while nematode Wolbachia mostly belong to clades C and D, but these relationships have been based on analysis of a small number of genes. To investigate the evolution and relationships of Wolbachia symbionts we have sequenced over 70 kb of the genome of wOvo, a Wolbachia from the human-parasitic nematode Onchocerca volvulus, and compared the genes identified to orthologues in other sequenced Wolbachia genomes. In comparisons of conserved local synteny, we find that wBm, from the nematode Brugia malayi, and wMel, from Drosophila melanogaster, are more similar to each other than either is to wOvo. Phylogenetic analysis of the protein-coding and ribosomal RNA genes on the sequenced fragments supports reciprocal monophyly of nematode and arthropod Wolbachia. The nematode Wolbachia did not arise from within the A clade of arthropod Wolbachia, and the root of the Wolbachia clade lies between the nematode and arthropod symbionts. Using the wOvo sequence, we identified a lateral transfer event whereby segments of the Wolbachia genome were inserted into the Onchocerca nuclear genome. This event predated the separation of the human parasite O. volvulus from its cattle-parasitic sister species, O. ochengi. The long association between filarial nematodes and Wolbachia symbionts may permit more frequent genetic exchange between their genomes

In Memoriam: Keith R. Briffa, 1952–2017

Keith R. Briffa was one of the most influential palaeoclimatologists of the last 30 years. His primary research interests lay in Late-Holocene climate change with a geographical emphasis on northern Eurasia. His greatest impact was in the field of dendroclimatology, a field that he helped to shape. His contributions have been seminal to the development of sound methods for tree-ring analysis and in their proper application to allow the interpretation of climate variability from tree rings. This led to the development of many important records that allow us to understand natural climate variability on timescales from years to millennia and to set recent climatic trends in their historical context

The use of a shear thinning polymer as a bubbly magma analogue for scaled laboratory experiments

Analogue materials are commonly used in volcanology to perform scaled laboratory experiments. Analogue experiments inform on fundamental fluid dynamic, structural and mechanical processes that are typically very difficult to observe and quantify directly in the natural volcanic system. Here we investigate the suitability of an aqueous solution of hydroxyethyl cellulose polymer (HEC) for use as a lava/magma analogue, with a particular focus on its rheological behaviour. We characterize a range of physical properties as functions of the concentration and temperature of the solution: density; specific heat capacity; thermal diffusivity; thermal conductivity; surface tension; as well as rheology. HEC has a non-Newtonian, shear-thinning rheology that depends on the concentration and temperature of the solution. We show that the rheology is well described by the Cross model, which was originally developed for polymer solutions, but has also been applied to bubbly magmas. Using this similarity, an approach for scaling analogue experiments that use shear-thinning polymers, like HEC, to bubbly magma is presented. A detailed workflow and a spreadsheet are provided to allow experimentalists to investigate the effects of non-Newtonian behaviour in their existing laboratory set-ups. This contribution will allow for the more complex, but often more realistic case of bubble-bearing magmas to be rigorously studied in experimental volcanology

IUPHAR-DB: An Expert-Curated, Peer-Reviewed Database of Receptors and Ion Channels

The International Union of Basic and Clinical Pharmacology database (IUPHAR-DB) integrates peer-reviewed pharmacological, chemical, genetic, functional and anatomical information on the 354 non-sensory G protein-coupled receptors (GPCRs), 71 ligand-gated ion channel subunits and 141 voltage-gated ion channel subunits encoded by the human, rat and mouse genomes. These genes represent the targets of about a third of currently approved drugs and are a major focus of drug discovery and development programs in the pharmaceutical industry. Individual gene pages provide a comprehensive description of the genes and their functions, with information on protein structure, ligands, expression patterns, signaling mechanisms, functional assays and biologically important receptor variants (e.g. single nucleotide polymorphisms and splice variants). The phenotypes resulting from altered gene expression (e.g. in genetically altered animals) and genetic mutations are described. Links are provided to bioinformatics resources such as NCBI RefSeq, OMIM, PubChem, human, rat and mouse genome databases. Recent developments include the addition of ligand-centered pages summarising information about unique ligand molecules in IUPHAR-DB. IUPHAR-DB represents a novel approach to biocuration because most data are provided through manual curation of published literature by a network of over 60 expert subcommittees coordinated by NC-IUPHAR. Data are referenced to the primary literature and linked to PubMed. The data are checked to ensure accuracy and consistency by the curators, added to the production server using custom-built submission tools and peer-reviewed by NC-IUPHAR, before being transferred to the public database. Data are reviewed and updated regularly (at least biennially). Other website features include comprehensive database search tools, online and downloadable gene lists and links to recent publications of interest to the field, such as reports on receptor-ligand pairings. The database is freely available at "http://www.iuphar-db.org":http://www.iuphar-db.org. Curators can be reached at curators [at] iuphar-db.org. We thank British Pharmacological Society, UNESCO (through the ICSU Grants Programme), Incyte, GlaxoSmithKline, Novartis, Servier and Wyeth for their support