115 research outputs found

    Biological Threats Are National Security Risks: Why COVID-19 Should Be a Wake up Call for Policy Makers

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    A national security strategy is the “nation’s plan for the coordinated use of all the instruments of state power—nonmilitary as well as military—to pursue objectives that defend and advance its national interest.” Perhaps the most straightforward national security objective is to protect the country from foreign invasion, but national security involves other objectives that aim to protect people in the United States as well as their values. For example, protecting U.S. elections from foreign interference is a security objective that advances the nation’s interest in democratic governance. The outbreak of a highly contagious disease like COVID‑19 strikes at the core of national security and the nation’s interest in protecting its citizens from unnecessary harm

    The reported durations of GOES Soft X-Ray flares in different solar cycles

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    The Geostationary Orbital Environmental Satellites (GOES) Soft X-ray (SXR) sensors have provided data relating to, inter alia, the time, intensity and duration of solar flares since the 1970s. The GOES SXR Flare List has become the standard reference catalogue for solar flares and is widely used in solar physics research and space weather. We report here that in the cur- rent version of the list there are significant differences between the mean du- ration of flares which occurred before May 1997 and the mean duration of flares thereafter. Our analysis shows that the reported flare timings for the pre-May 1997 data were not based on the same criteria as is currently the case. This finding has serious implications for all those who used flare duration (or fluence, which depends on the chosen start and end times) as part of their analysis of pre-May 1997 solar events, or statistical analyses of large sam- ples of flares, e.g. as part of the assessment of a Solar Energetic Particle fore- casting algorithm

    Targeted metagenomic recovery of four divergent viruses reveals shared and distinctive characteristics of giant viruses of marine eukaryotes

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    Giant viruses have remarkable genomic repertoires—blurring the line with cellular life—and act as top–down controls of eukaryotic plankton. However, to date only six cultured giant virus genomes are available from the pelagic ocean. We used at-sea flow cytometry with staining and sorting designed to target wild predatory eukaryotes, followed by DNA sequencing and assembly, to recover novel giant viruses from the Pacific Ocean. We retrieved four ‘PacV’ partial genomes that range from 421 to 1605 Kb, with 13 contigs on average, including the largest marine viral genomic assembly reported to date. Phylogenetic analyses indicate that three of the new viruses span a clade with deep-branching members of giant Mimiviridae, incorporating the Cafeteria roenbergensis virus, the uncultivated terrestrial Faunusvirus, one PacV from a choanoflagellate and two PacV with unclear hosts. The fourth virus, oPacV-421, is phylogenetically related to viruses that infect haptophyte algae. About half the predicted proteins in each PacV have no matches in NCBI nr (e-value < 10−5), totalling 1735 previously unknown proteins; the closest affiliations of the other proteins were evenly distributed across eukaryotes, prokaryotes and viruses of eukaryotes. The PacVs encode many translational proteins and two encode eukaryotic-like proteins from the Rh family of the ammonium transporter superfamily, likely influencing the uptake of nitrogen during infection. cPacV-1605 encodes a microbial viral rhodopsin (VirR) and the biosynthesis pathway for the required chromophore, the second finding of a choanoflagellate-associated virus that encodes these genes. In co-collected metatranscriptomes, 85% of cPacV-1605 genes were expressed, with capsids, heat shock proteins and proteases among the most highly expressed. Based on orthologue presence–absence patterns across the PacVs and other eukaryotic viruses, we posit the observed viral groupings are connected to host lifestyles as heterotrophs or phototrophs

    Experimental study of surface curvature effects on aerodynamic performance of a low Reynolds number airfoil for use in small wind turbines

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    This paper presents the wind tunnel experimental results to investigate the effects of surface gradient-of-curvature on aerodynamic performance of a low Reynolds number airfoil Eppler 387 for use in small-scale wind turbines. The prescribed surface curvature distribution blade design method is applied to the airfoil E387 to remove the gradient-of-curvature discontinuities and the redesigned airfoil is denoted as A7. Both airfoils are manufactured with high precision to reflect the design. Low-speed wind tunnel experiments are conducted to both airfoils at chord based Reynolds numbers 100 000, 200 000, and 300 000. Surface pressure measurements are used to calculate the lift and pitching-moment data, and the wake survey method is applied to obtain the drag data. The experimental results of E387 are compared with NASA Low Turbulence Pressure Tunnel (LTPT) results for validation. The gradient-of-curvature discontinuities of E387 result in a larger laminar separation bubble which causes higher drag at lower angles of attack. As the angle of attack increases the separation bubble of the airfoil E387 moves faster towards the leading edge than that of A7, resulting in a premature bubble bursting and earlier stall on E387. The impact of the gradient-of-curvature distribution on the airfoil performance is more profound at higher angles of attack and lower Reynolds number. The aerodynamic improvements are integrated over the 3D geometry of a 3 kW small wind turbine, resulting in up to 10% increase in instantaneous power and 1.6% increase in annual energy production. It is experimentally concluded that an improved curvature distribution results in a better airfoil performance, leading to higher energy output efficiency

    Ecophysiology of uncultivated marine euryarchaea is linked to particulate organic matter

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    Particles in aquatic environments host distinct communities of microbes, yet the evolution of particlespecialized taxa and the extent to which specialized microbial metabolism is associated with particles is largely unexplored. Here, we investigate the hypothesis that a widely distributed and uncultivated microbial group - the marine group II euryarchaea (MGII) - interacts with living and detrital particulate organic matter (POM) in the euphotic zone of the central California Current System. Using fluorescent in situ hybridization, we verified the association of euryarchaea with POM. We further quantified the abundance and distribution of MGII 16S ribosomal RNA genes in size-fractionated seawater samples and compared MGII functional capacity in metagenomes from the same fractions. The abundance of MGII in free-living and &lt;3 μm fractions decreased with increasing distance from the coast, whereas MGII abundance in the 0.8-3 lm fraction remained constant. At several offshore sites, MGII abundance was highest in particle fractions, indicating that particle-attached MGII can outnumber free-living MGII under oligotrophic conditions. Compared with free-living MGII, the genome content of MGII in particleassociated fractions exhibits an increased capacity for surface adhesion, transcriptional regulation and catabolism of high molecular weight substrates. Moreover, MGII populations in POM fractions are phylogenetically distinct from and more diverse than free-living MGII. Eukaryotic phytoplankton additions stimulated MGII growth in bottle incubations, providing the first MGII net growth rate measurements. These ranged from 0.47 to 0.54 d-1. However, MGII were not recovered in wholegenome amplifications of flow-sorted picoeukaryotic phytoplankton and heterotrophic nanoflagellates, suggesting that MGII in particle fractions are not physically attached to living POM. Collectively, our results support a linkage between MGII ecophysiology and POM, implying that marine archaea have a role in elemental cycling through interactions with particles. © 2015 International Society for Microbial Ecology. All rights reserved

    A recurrent mitochondrial p.Trp22Arg NDUFB3 variant causes a distinctive facial appearance, short stature and a mild biochemical and clinical phenotype

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    Background Isolated Complex I deficiency is the most common paediatric mitochondrial disease presentation, associated with poor prognosis and high mortality. Complex I comprises 44 structural subunits with at least 10 ancillary proteins; mutations in 29 of these have so far been associated with mitochondrial disease but there are limited genotype-phenotype correlations to guide clinicians to the correct genetic diagnosis. Methods Patients were analysed by whole-exome sequencing, targeted capture or candidate gene sequencing. Clinical phenotyping of affected individuals was performed. Results We identified a cohort of 10 patients from 8 families (7 families are of unrelated Irish ancestry) all of whom have short stature (C, p.Trp22Arg NDUFB3 variant. Two sibs presented with primary short stature without obvious metabolic dysfunction. Analysis of skeletal muscle from three patients confirmed a defect in Complex I assembly. Conclusions Our report highlights that the long-term prognosis related to the p.Trp22Arg NDUFB3 mutation can be good, even for some patients presenting in acute metabolic crisis with evidence of an isolated Complex I deficiency in muscle. Recognition of the distinctive facial features—particularly when associated with markers of mitochondrial dysfunction and/or Irish ancestry—should suggest screening for the p.Trp22Arg NDUFB3 mutation to establish a genetic diagnosis, circumventing the requirement of muscle biopsy to direct genetic investigations

    Suppression of Autophagy Dysregulates the Antioxidant Response and Causes Premature Senescence of Melanocytes

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    YesAutophagy is the central cellular mechanism for delivering organelles and cytoplasm to lysosomes for degradation and recycling of their molecular components. To determine the contribution of autophagy to melanocyte (MC) biology, we inactivated the essential autophagy gene Atg7 specifically in MCs using the Cre-loxP system. This gene deletion efficiently suppressed a key step in autophagy, lipidation of microtubule-associated protein 1 light chain 3 beta (LC3), in MCs and induced slight hypopigmentation of the epidermis in mice. The melanin content of hair was decreased by 10–15% in mice with autophagy-deficient MC as compared with control animals. When cultured in vitro, MCs from mutant and control mice produced equal amounts of melanin per cell. However, Atg7-deficient MCs entered into premature growth arrest and accumulated reactive oxygen species (ROS) damage, ubiquitinated proteins, and the multi-functional adapter protein SQSTM1/p62. Moreover, nuclear factor erythroid 2–related factor 2 (Nrf2)–dependent expression of NAD(P)H dehydrogenase, quinone 1, and glutathione S-transferase Mu 1 was increased, indicating a contribution of autophagy to redox homeostasis in MCs. In summary, the results of our study suggest that Atg7-dependent autophagy is dispensable for melanogenesis but necessary for achieving the full proliferative capacity of MCs

    A future for game histories?

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    Recent years have seen an efflorescence of writing and curatorial work focused upon the past of video games. However, this work has tended to concentrate on particular forms of analysis, and privileged certain kinds of discourse. This article argues that these approaches limit our capacity to produce effective histories of and around games, and proposes more nuanced histories, informed by Foucauldian ideas of a genealogical approach to historical work, and a clear sense of the voices that present histories fail to represent. Broader, cultural game histories, we contend, offer us a clearer understanding of games’ past, and can move us away from the teleological, deterministic, and “great man” histories which dominate the present landscape. Reflecting on the past in this way also suggests an agenda for the future, in encouraging us to consider how and to what end we preserve video game culture

    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]
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