1,292 research outputs found
Wolfpack: Measure and Counter
Intelligence, communications, and submerged speed were the critical factors in wolfpack tactics in the Battle of the Atlantic
Accumulation of Sellafield-derived radiocarbon (14C) in Irish Sea and West of Scotland intertidal shells and sediments
The nuclear energy industry produces radioactive waste at various stages of the fuel cycle. In
the United Kingdom, spent fuel is reprocessed at the Sellafield facility in Cumbria on the
north west coast of England. Waste generated at the site comprises a wide range of
radionuclides including radiocarbon (14C) which is disposed of in various forms including
highly soluble inorganic carbon within the low level liquid radioactive effluent, via pipelines
into the Irish Sea. This 14C is rapidly incorporated into the dissolved inorganic carbon (DIC)
reservoir and marine calcifying organisms, e.g. molluscs, readily utilise DIC for shell
formation. This study investigated a number of sites located in Irish Sea and West of Scotland
intertidal zones. Results indicate 14C enrichment above ambient background levels in shell
material at least as far as Port Appin, 265 km north of Sellafield. Of the commonly found
species (blue mussel (Mytilus edulis), common cockle (Cerastoderma edule) and common
periwinkle (Littorina littorea)), mussels were found to be the most highly enriched in 14C due
to the surface environment they inhabit and their feeding behaviour. Whole mussel shell
activities appear to have been decreasing in response to reduced discharge activities since the
early 2000s but in contrast, there is evidence of continuing enrichment of the carbonate
sediment component due to in-situ shell erosion, as well as indications of particle transport of
fine 14C-enriched material close to Sellafield
Ecosystem uptake and transfer of Sellafield-derived radiocarbon (14C). Part 1. The Irish Sea
Ecosystem uptake and transfer processes of Sellafield-derived radiocarbon (14C) within the Irish Sea were examined. Highly variable activities in sediment, seawater and biota indicate complex 14C dispersal and uptake dynamics. All east basin biota exhibited 14C enrichments above ambient background while most west basin biota had 14C activities close to background, although four organisms including two slow-moving species were significantly enriched. The western Irish Sea gyre is a suggested pathway for transfer of 14C to the west basin and retention therein. Despite ongoing Sellafield 14C discharges, organic sediments near Sellafield were significantly less enriched than associated benthic organisms. Rapid scavenging of labile, 14C-enriched organic material by organisms and mixing to depth of 14C-enriched detritus arriving at the sediment/water interface are proposed mechanisms to explain this. All commercially important fish, crustaceans and molluscs showed 14C enrichments above background; however, the radiation dose from their consumption is extremely low and radiologically insignificant
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iBBiG: iterative binary bi-clustering of gene sets
Motivation: Meta-analysis of genomics data seeks to identify genes associated with a biological phenotype across multiple datasets; however, merging data from different platforms by their features (genes) is challenging. Meta-analysis using functionally or biologically characterized gene sets simplifies data integration is biologically intuitive and is seen as having great potential, but is an emerging field with few established statistical methods. Results: We transform gene expression profiles into binary gene set profiles by discretizing results of gene set enrichment analyses and apply a new iterative bi-clustering algorithm (iBBiG) to identify groups of gene sets that are coordinately associated with groups of phenotypes across multiple studies. iBBiG is optimized for meta-analysis of large numbers of diverse genomics data that may have unmatched samples. It does not require prior knowledge of the number or size of clusters. When applied to simulated data, it outperforms commonly used clustering methods, discovers overlapping clusters of diverse sizes and is robust in the presence of noise. We apply it to meta-analysis of breast cancer studies, where iBBiG extracted novel gene set—phenotype association that predicted tumor metastases within tumor subtypes
Morphology of small-scale submarine mass movement events across the northwest United Kingdom
A review of multibeam echo sounder (MBES) survey data from five locations around the United Kingdom northwest coast has led to the identification of a total of 14 separate subaqueous mass movement scars and deposits within the fjords (sea lochs) and coastal inlets of mainland Scotland, and the channels between the islands of the Inner Hebrides. In these areas, Quaternary sediment deposition was dominated by glacial and glaciomarine processes. Analysis of the morphometric parameters of each submarine mass movement has revealed that they fall into four distinct groups of subaqueous landslides; Singular Slumps, Singular Translational, Multiple Single-Type, and Complex (translational & rotational) failures. The Singular Slump Group includes discrete, individual subaqueous slumps that exhibit no evidence of modification through the merging of several scars. The Singular Translational Group comprise a single slide that displays characteristics associated with a single translational (planar) failure with no merging of multiple events. The Multiple Single-Type Group incorporates scars and deposits that displayed morphometric features consistent with the amalgamation of several failure events of the same type (e.g. debris flows or slumps). Finally, the Complex (translational & rotational) Group comprises landslides that exhibited complex styles of failures, including both translational and rotational mechanisms controlling the same slide. The submarine mass movements that comprise this dataset are then discussed in relation to global fjordic and glaciomarine nearshore settings, and slope failure trigger mechanisms associated with these environments are described with tentative links to individual submarine landslides from the database, where appropriate. It is acknowledged that additional MBES data are needed not only to expand this database, but also in order to create a more statistically robust study. However, this initial study provides the basis for a much wider investigation of subaqueous mass movements and correlations between their morphometric parameters
The Crisis in Science Education: Problems and Recommendations: A Summary of the Iowa Academy of Science Symposium at Luther College, Decorah, Iowa, April 22, 1983
There is a recognized state and national crisis in securing and maintaining qualified science teachers. To date the majority of effort has been expended toward identifying and redefining the problems with few attempts made to resolve them. The purpose of this symposium was to spend minimal time seeking to inform participants of the problems and then to present some recommendations for resolving them. Each of the presenters was uniquely to address this, to date, intractable problem
Latest Quaternary palaeoceanographic change in the eastern North Atlantic based upon a dinoflagellate cyst event ecostratigraphy
AbstractThe analyses of dinoflagellate cyst records, from the latest Quaternary sediments recovered from DSDP Core 610A taken on the Feni Ridge in the southern Rockall Trough, and part of core MD01-2461 on the continental margin of the Porcupine Seabight in the eastern North Atlantic Ocean, has provided evidence for significant oceanographic change encompassing the Last Glacial Maximum (LGM) and part of the Holocene. This together with other published records has led to a regional evaluation of oceanographic change in the eastern North Atlantic over the past 68 ka, based upon a distinctive dinoflagellate event ecostratigraphy. These changes reflect changes in the surface waters of the North Atlantic Current (NAC), and perhaps the deeper thermohaline Atlantic Meridional Overturning Circulation (AMOC), driving fundamental regime changes within the phytoplanktonic communities. Three distinctive dinoflagellate cyst associations based upon both factor and cluster analyses have been recognised. Associations characterised by Bitectatodinium tepikiense (between 61.1 ± 6.2 to 13.4 ± 1.1 ka BP), Nematosphaeropsis labyrinthus (between 10.5 ± 0.3 and 11.45 ± 0.8 ka. BP), and the cyst of Protoceratium reticulatum (between 8.5 ± 0.9 and 5.2 ± 1.3 ka. BP) indicate major change within the eastern North Atlantic oceanography. The transitions between these changes occur over a relatively short time span (c.1.5 ka), given our sampling resolution, and have the potential to be incorporated into an event stratigraphy through the latest Quaternary as recommended by the INTIMATE (INTegrating Ice core, MArine and TErrestrial records) group. The inclusion of a dinoflagellate cyst event stratigraphy would highlight changes within the phytoplankton of the North Atlantic Ocean as a fully glacial world changed to our present interglacial
Ex-vivo HRMAS of adult brain tumours: metabolite quantification and assignment of tumour biomarkers
Background: High-resolution magic angle spinning (HRMAS) NMR spectroscopy allows detailed metabolic analysis
of whole biopsy samples for investigating tumour biology and tumour classification. Accurate biochemical
assignment of small molecule metabolites that are “NMR visible” will improve our interpretation of HRMAS data
and the translation of NMR tumour biomarkers to in-vivo studies.
Results: 1D and 2D 1H HRMAS NMR was used to determine that 29 small molecule metabolites, along with 8 macromolecule signals, account for the majority of the HRMAS spectrum of the main types of brain tumour(astrocytoma grade II, grade III gliomas, glioblastomas, metastases, meningiomas and also lymphomas). Differences in concentration of 20 of these metabolites were statistically significant between these brain tumour types. During the course of an extended 2D data acquisition the HRMAS technique itself affects sample analysis: glycine, glutathione and glycerophosphocholine all showed small concentration changes; analysis of the sample after HRMAS indicated structural damage that may affect subsequent histopathological analysis.
Conclusions: A number of small molecule metabolites have been identified as potential biomarkers of tumour
type that may enable development of more selective in-vivo 1H NMR acquisition methods for diagnosis and prognosis of brain tumours
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