Air cushion vehicles: A briefing

Experience and characteristics; the powering, uses, and implications of large air cushion vehicles (ACV); and the conceptual design and operation of a nuclear powered ACV freighter and supporting facilities are described

Open vs.Closed standards for ambient intelligence: an exploratory study of adoption

Emerging forms of structurally complex information systems, such as Ambient Intelligence (AmI), requires the integration of a range of technologies. To enable such systems’ development there is a reliance on interoperability standards. However, due to their inherent characteristics, the adoption of open or closed standards by technology vendors can have impacts the later stages of the adoption and diffusion of systems. This paper reports on research-in-progress which explores the adoption of open and closed standards by technology vendors engaged in AmI development. Existing models of innovation adoption and diffusion fail to adequately account for adoption in more complex technological contexts. In order to address such deficiencies, current perspectives on standards are discussed, before a conceptual framework for structuring the research is proposed which integrates both existing adoption theory and standards-oriented research. The use of the European Consumer Electronics sector as a unit of analysis is discussed, before concluding with an overview of how the study will progress

Live imaging of Drosophila gonad formation reveals roles for Six4 in regulating germline and somatic cell migration

<p>Abstract</p> <p>Background</p> <p>Movement of cells, either as amoeboid individuals or in organised groups, is a key feature of organ formation. Both modes of migration occur during <it>Drosophila </it>embryonic gonad development, which therefore provides a paradigm for understanding the contribution of these processes to organ morphogenesis. Gonads of Drosophila are formed from three distinct cell types: primordial germ cells (PGCs), somatic gonadal precursors (SGPs), and in males, male-specific somatic gonadal precursors (msSGPs). These originate in distinct locations and migrate to associate in two intermingled clusters which then compact to form the spherical primitive gonads. PGC movements are well studied, but much less is known of the migratory events and other interactions undergone by their somatic partners. These appear to move in organised groups like, for example, lateral line cells in zebra fish or <it>Drosophila </it>ovarian border cells.</p> <p>Results</p> <p>We have used time-lapse fluorescence imaging to characterise gonadal cell behaviour in wild type and mutant embryos. We show that the homeodomain transcription factor Six4 is required for the migration of the PGCs and the msSGPs towards the SGPs. We have identified a likely cause of this in the case of PGCs as we have found that Six4 is required for expression of <it>Hmgcr </it>which codes for HMGCoA reductase and is necessary for attraction of PGCs by SGPs. Six4 affects msSGP migration by a different pathway as these move normally in <it>Hmgcr </it>mutant embryos. Additionally, embryos lacking fully functional Six4 show a novel phenotype in which the SGPs, which originate in distinct clusters, fail to coalesce to form unified gonads.</p> <p>Conclusion</p> <p>Our work establishes the <it>Drosophila </it>gonad as a model system for the analysis of coordinated cell migrations and morphogenesis using live imaging and demonstrates that Six4 is a key regulator of somatic cell function during gonadogenesis. Our data suggest that the initial association of SGP clusters is under distinct control from the movements that drive gonad compaction.</p

Preliminary impact speed and angle criteria for design of a nuclear airplane fission product containment vessel

Studying aircraft accidents to determine impact angle and speed criteria for designing nuclear airplane fission product containment vesse

Topographic Constraints on Magma Accumulations Below the Actively Uuplifting Uturuncu and Lazufre Volcanic Centers in the Central Andes

Geodetic surveys of Volcán Uturuncu and the Lazufre volcanic complex in the Central Andes of South America reveal sustained surface uplift from magmatic intrusion at depth. However, the decadal timescales of geodetic surveys are short relative to the timescales of magma chamber growth. Thus, from geodesy alone, it is difficult to infer the deformation and hence magma accumulation history of these volcanoes. Here we combine data from InSAR, long-wavelength topography, GPS and high-resolution topographic surveys of lake shorelines and rivers, and lava flow morphology to constrain the spatial and temporal evolution of magmatism at Uturuncu and Lazufre. Near Uturuncu, dated lake shorelines show no evidence of tilting since ca. 16 ka, and we find no evidence of deformation in the long-wavelength topography. A lack of net surface displacement suggests that uplift related to a rising diapir must be less than a century old, or, more likely, magmatic inflation at Uturuncu is transient over millennial timescales and is therefore not recorded in the topography. At Lazufre, we also find no evidence for sustained uplift recorded in Late Pleistocene lake shorelines. However, the orientations of multiple dated lava flows suggest that the long-wavelength dome at the center of Lazufre’s uplift has persisted since at least 400 ka. Additionally, we find that the radial distribution of volcanic vents at Lazufre, coupled with the presence of an apical graben, is consistent with experimental and theoretical predictions of magmatic doming. The dome’s longevity indicates significant magma storage at depth, and therefore Lazufre is likely a highly evolved pre-caldera magmatic system. These two case studies demonstrate that combining geomorphic and geophysical data sets to extend the geodetic record back in time can help determine the style and magnitude of magma transport in volcanic systems

Identification of Novel Cetacean Poxviruses in Cetaceans Stranded in South West England

Poxvirus infections in marine mammals have been mainly reported through their clinical lesions and electron microscopy (EM). Poxvirus particles in association with such lesions have been demonstrated by EM and were previously classified as two new viruses, cetacean poxvirus 1 (CePV-1) and cetacean poxvirus 2 (CePV-2). In this study, epidermal pox lesions in cetaceans stranded in South West England (Cornwall) between 2008 and 2012 were investigated by electron microscopy and molecular analysis. PCR and sequencing of a highly conserved region within the viral DNA polymerase gene ruled out both parapoxand orthopoxviruses. Moreover, phylogenetic analysis of the PCR product clustered the sequences with those previously described as cetacean poxviruses. However, taking the close genetic distance of this gene fragment across the family of poxviridae into account, it is reasonable to postulate further, novel cetacean poxvirus species. The nucleotide similarity within each cluster (tentative species) detected ranged from 98.6% to 100%, whilst the similarity between the clusters was no more than 95%. The detection of several species of poxvirus in different cetacean species confirms the likelihood of a heterogeneous cetacean poxvirus genus, comparable to the heterogeneity observed in other poxvirus genera

Galaxy And Mass Assembly (GAMA) : the absence of stellar mass segregation in galaxy groups and consistent predictions from GALFORM and EAGLE simulations

We investigate the contentious issue of the presence, or lack thereof, of satellites mass segregation in galaxy groups using the Galaxy And Mass Assembly (GAMA) survey, the galform semi-analytic, and the EAGLE cosmological hydrodynamical simulation catalogues of galaxy groups. We select groups with halo mass 12 ≤ log (Mhalo/h−1 M⊙) < 14.5 and redshift z ≤ 0.32 and probe the radial distribution of stellar mass out to twice the group virial radius. All the samples are carefully constructed to be complete in stellar mass at each redshift range and efforts are made to regularize the analysis for all the data. Our study shows negligible mass segregation in galaxy group environments with absolute gradients of ≲0.08 dex and also shows a lack of any redshift evolution. Moreover, we find that our results at least for the GAMA data are robust to different halo mass and group centre estimates. Furthermore, the EAGLE data allows us to probe much fainter luminosities (r-band magnitude of 22) as well as investigate the three-dimensional spatial distribution with intrinsic halo properties, beyond what the current observational data can offer. In both cases we find that the fainter EAGLE data show a very mild spatial mass segregation at z ≤ 0.22, which is again not apparent at higher redshift. Interestingly, our results are in contrast to some earlier findings using the Sloan Digital Sky Survey. We investigate the source of the disagreement and suggest that subtle differences between the group-finding algorithms could be the root cause.Publisher PDFPeer reviewe