710 research outputs found
Virtual aids to navigation
There are many examples of master, bridge crew and pilot errors in navigation causing grounding under adverse circumstances that were known and published in official notices and records. Also dangerous are hazards to navigation resulting from dynamic changes within the marine environment, inadequate surveys and charts. This research attempts to reduce grounding and allision incidents and increase safety of navigation by expanding mariner situational awareness at and below the waterline using new technology and developing methods for the creation, implementation and display of Virtual Aids to Navigation (AtoN) and related navigation information. This approach has widespread significance beyond commonly encountered navigation situations. Increased vessel navigation activity in the Arctic and sub-Arctic regions engenders risk due, in part, to the inability to place navigational aids and buoys in constantly changing ice conditions. Similar conditions exist in tropical regions where sinker placement to moor buoys in sensitive environmental areas with coral reefs is problematic. Underdeveloped regions also lack assets and infrastructure needed to provide adequate navigation services, and infrastructure can also rapidly perish in developed regions during times of war and natural disaster. This research exploits rapidly developing advances in environmental sensing technology, evolving capabilities and improved methods for reporting real time environmental data that can substantially expand electronic navigation aid availability and improve knowledge of undersea terrain and imminent hazards to navigation that may adversely affect ship operations. This is most needed in areas where physical aids to navigation are scarce or non-existent as well as in areas where vessel traffic is congested. Research to expand related vessel capabilities is accomplished to overcome limitations in existing and planned electronic aids, expanding global capabilities and resources at relatively low-cost. New methods for sensor fusion are also explored to
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reduce overall complexity and improve integration with other navigation systems with the goal of simplifying navigation tasks. An additional goal is to supplement training program content by expanding technical resources and capabilities within the confines of existing International Convention on Standards for Training, Certification and Watchkeeping for Seafarers (STCW) requirements, while improving safety by providing new techniques to enhance situational awareness
New Sensor Technology Integration for safe and efficient e-Navigation
This paper discusses the relation of new sensor technology on bridge resource management as pertaining to the integration of new information sources and types for ship navigation in a future e-Navigation environment. An overview of several new technologies will be provided showing how systems and devices currently available in the commercial marketplace are being adapted and used to aid ship navigation planning and decision making. Examples include live Doppler radar useful for coastal navigation available from land-based sources through broadband Internet connections, imagery from unmanned aerial vehicles to aid in ice-navigation in, and forward-looking sonar for navigating in poorly charted, uncharted and other world regions where aids to navigation are not readily available. The use of such innovative methods are not yet covered in IMO Guidelines, as e.g., for Voyage Planning, the Procedures Manual of a ship’s Safety Management System or any other document to illustrate the adoption of such technology, but needs to be considered and investigated. However, the implications of introducing such new information sources in terms of bridge watchstander (Officer of the Watch - OOW) workload and training are discussed with respect to existing guidelines and regulations. Further illustration is provided in the context of how such new information sources may be integrated with existing resources to enhance overall navigation situational awareness. This includes the information itself as well as the means and methods used to interact with the OOW in terms of bridge displays, monitors and alarms. Selected specific details of research efforts currently underway will be provided in terms of forward-looking sonar integration into the bridge environment and navigation processes. This will include results obtained from experimental studies in the laboratory as well as on a suitably equipped research vessel test bed. A description of achievements accomplished to date will be provided in terms of tasks performed; the processes and procedures employed to acquire, manage and evaluate these tasks; preliminary results and outcomes achieved; and metrics used to measure these outcomes in terms of determining whether the research goals are achievable. Comparisons between expectations and actual results will be discussed, along with an analysis of risks encountered. Lessons learned are documented regarding errors in input, process, product and/or metrics
Robust Weak-lensing Mass Calibration of Planck Galaxy Clusters
In light of the tension in cosmological constraints reported by the Planck
team between their SZ-selected cluster counts and Cosmic Microwave Background
(CMB) temperature anisotropies, we compare the Planck cluster mass estimates
with robust, weak-lensing mass measurements from the Weighing the Giants (WtG)
project. For the 22 clusters in common between the Planck cosmology sample and
WtG, we find an overall mass ratio of \left =
0.688 \pm 0.072. Extending the sample to clusters not used in the Planck
cosmology analysis yields a consistent value of from 38 clusters in common. Identifying the
weak-lensing masses as proxies for the true cluster mass (on average), these
ratios are lower than the default mass bias of 0.8 assumed in
the Planck cluster analysis. Adopting the WtG weak-lensing-based mass
calibration would substantially reduce the tension found between the Planck
cluster count cosmology results and those from CMB temperature anisotropies,
thereby dispensing of the need for "new physics" such as uncomfortably large
neutrino masses (in the context of the measured Planck temperature anisotropies
and other data). We also find modest evidence (at 95 per cent confidence) for a
mass dependence of the calibration ratio and discuss its potential origin in
light of systematic uncertainties in the temperature calibration of the X-ray
measurements used to calibrate the Planck cluster masses. Our results exemplify
the critical role that robust absolute mass calibration plays in cluster
cosmology, and the invaluable role of accurate weak-lensing mass measurements
in this regard.Comment: 5 pages, 2 figure
Late Holocene Rupture History of the Alpine Fault in South Westland, New Zealand
Abstract Strata and fault relationships revealed in five trenches excavated across the recent trace of the Alpine fault at the Haast, Okuru, and Turnbull Rivers, South Westland, New Zealand, record the three most recent surface-faulting events. Using back-stripping techniques to remove the three faulting events and the sedimentary units associated with the faulting restores the cross-sections to gravel-bed floodplains at the Haast and Okuru Rivers, at about A.D. 750. Horizontal and vertical offsets of stream channels and terrace risers reveal characteristic displacements of about 8–9 m dextral and up to 1 m vertical per event. Cumulative dextral displacement is 25 ± 3 m in the past three events. The most recent surface-rupture event was probably in A.D. 1717, and the next prior events were about A.D. 1230 ± 50 and about A.D.750 ± 50. The timing of these events is consistent with past large-great earth- quakes on the southern section of the Alpine fault inferred from off-fault data, but there are fewer events identified in trenches. Our three-event dataset indicates the aver- age surface-rupture recurrence interval for the South Westland section of the fault is about 480 years, much longer than the current elapsed time of 295 years. Therefore, the Alpine fault in South Westland may not be close to rupture as is often speculated
Mapping the H2 resistance effective against Globodera pallida pathotype Pa1 in tetraploid potato
This work was supported by the Rural & Environment Science & Analytical Services Division of the Scottish Government, the BBSRC, through the joint projects CRF/2009/SCRI/SOP 0929, BB/L008025/1 and BB/K018299/1. Additional funding was obtained through the James Hutton Institute SEEDCORN initiative, AHDB Potato, the Perry Foundation and The Felix Cobbold Trust. Amanpreet Kaur was supported by the Commonwealth Scholarship Commission through a Commonwealth split-site Ph.D. grant.Key message: The nematode resistance gene H2 was mapped to the distal end of chromosome 5 in tetraploid potato. The H2 resistance gene, introduced into cultivated potatoes from the wild diploid species Solanum multidissectum, confers a high level of resistance to the Pa1 pathotype of the potato cyst nematode Globodera pallida. A cross between tetraploid H2-containing breeding clone P55/7 and susceptible potato variety Picasso yielded an F1 population that segregated approximately 1:1 for the resistance phenotype, which is consistent with a single dominant gene in a simplex configuration. Using genome reduction methodologies RenSeq and GenSeq, the segregating F1 population enabled the genetic characterisation of the resistance through a bulked segregant analysis. A diagnostic RenSeq analysis of the parents confirmed that the resistance in P55/7 cannot be explained by previously characterised resistance genes. Only the variety Picasso contained functionally characterised disease resistance genes Rpi-R1, Rpi-R3a, Rpi-R3b variant, Gpa2 and Rx, which was independently confirmed through effector vacuum infiltration assays. RenSeq and GenSeq independently identified sequence polymorphisms linked to the H2 resistance on the top end of potato chromosome 5. Allele-specific KASP markers further defined the locus containing the H2 gene to a 4.7Â Mb interval on the distal short arm of potato chromosome 5 and to positions that correspond to 1.4Â MB and 6.1Â MB in the potato reference genome.Publisher PDFPeer reviewe
Economics of some soil conservation practices
In applying conservation and fertility improvement plans, farmers have a choice between alternative combinations of land use, fertilizer applications and erosion control practices. Within limits, they may choose between different rotations and different fertilizer applications combined with different erosion control practices and still farm the land in accordance with the soil capabilities.
While land use in accordance with soil capabilities and appropriate fertilization is basic to soil conservation, these measures need to be supplemented by supporting conservation practices such as contouring, sod waterways, mulching, drainage, flumes, etc., if soil is to be conserved and improved most efficiently.
Successful conservation farming (that system which will increase total farm production, build up soil fertility, control erosion and maximize earnings) cannot be tailor-made to fit all farms but involves consideration of each individual\u27s situation. The farmer (and those working with him) must analyze his problem to determine his costs and returns for the farm as a whole under alternative combinations of crops, fertilization and supporting conservation measures to determine which system will best fit his capital position and abilities and still do the conservation job
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Host-microbiome interactionsin human type 2 diabetes following prebiotic fibre (galactooligosaccharide) intake
Aberrant microbiota composition and function have been linked to several pathologies, including type 2 diabetes. In animal models, prebiotics induce favourable changes in the intestinal microbiota, intestinal permeability (IP) and endotoxaemia, which are linked to concurrent improvement in glucose tolerance. This is the first study to investigate the link between IP, glucose tolerance and intestinal bacteria in human type 2 diabetes. In all, twenty-nine men with well-controlled type 2 diabetes were randomised to a prebiotic (galacto-oligosaccharide mixture) or placebo (maltodextrin) supplement (5·5 g/d for 12 weeks). Intestinal microbial community structure, IP, endotoxaemia, inflammatory markers and glucose tolerance were assessed at baseline and post intervention. IP was estimated by the urinary recovery of oral 51Cr-EDTA and glucose tolerance by insulin-modified intravenous glucose tolerance test. Intestinal microbial community analysis was performed by high-throughput next-generation sequencing of 16S rRNA amplicons and quantitative PCR. Prebiotic fibre supplementation had no significant effects on clinical outcomes or bacterial abundances compared with placebo; however, changes in the bacterial family Veillonellaceae correlated inversely with changes in glucose response and IL-6 levels (r −0·90, P=0·042 for both) following prebiotic intake. The absence of significant changes to the microbial community structure at a prebiotic dosage/length of supplementation shown to be effective in healthy individuals is an important finding. We propose that concurrent metformin treatment and the high heterogeneity of human type 2 diabetes may have played a significant role. The current study does not provide evidence for the role of prebiotics in the treatment of type 2 diabetes
Galaxy Properties from the Ultra-violet to the Far-Infrared: Lambda-CDM models confront observations
We combine a semi-analytic model of galaxy formation with simple analytic
recipes describing the absorption and re-emission of starlight by dust in the
interstellar medium of galaxies. We use the resulting models to predict galaxy
counts and luminosity functions from the far-ultraviolet to the sub-mm, from
redshift five to the present, and compare with an extensive compilation of
observations. We find that in order to reproduce the rest-UV and optical
luminosity functions at high redshift, we must assume an evolving normalization
in the dust-to-metal ratio, implying that galaxies of a given bolometric
luminosity (or metal column density) must be less extinguished than their local
counterparts. In our best-fit model, we find remarkably good agreement with
observations from rest-frame 1500 Angstroms to 250 microns. At longer
wavelengths, most dramatically in the sub-mm, our models underpredict the
number of bright galaxies by a large factor. The models reproduce the observed
total IR luminosity function fairly well. We show the results of varying
several ingredients of the models, including various aspects of the dust
attenuation recipe, the dust emission templates, and the cosmology. We use our
models to predict the integrated Extragalactic Background Light (EBL), and
compare with an observationally-motivated EBL model and with other available
observational constraints.Comment: 27 pages, 17 figures, 1 table, accepted to MNRAS, this version
matches accepted manuscrip
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