247 research outputs found

    Combining univariate approaches for ensemble change detection in multivariate data

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    Detecting change in multivariate data is a challenging problem, especially when class labels are not available. There is a large body of research on univariate change detection, notably in control charts developed originally for engineering applications. We evaluate univariate change detection approaches —including those in the MOA framework — built into ensembles where each member observes a feature in the input space of an unsupervised change detection problem. We present a comparison between the ensemble combinations and three established ‘pure’ multivariate approaches over 96 data sets, and a case study on the KDD Cup 1999 network intrusion detection dataset. We found that ensemble combination of univariate methods consistently outperformed multivariate methods on the four experimental metrics.project RPG-2015-188 funded by The Leverhulme Trust, UK; Spanish Ministry of Economy and Competitiveness through project TIN 2015-67534-P and the Spanish Ministry of Education, Culture and Sport through Mobility Grant PRX16/00495. The 96 datasets were originally curated for use in the work of Fernández-Delgado et al. [53] and accessed from the personal web page of the author5. The KDD Cup 1999 dataset used in the case study was accessed from the UCI Machine Learning Repository [10

    Re-evaluating ambiguous age relationships in Archean cratons: implications for the origin of ultramafic-mafic complexes in the Lewisian Gneiss Complex

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Archean ultramafic-mafic complexes have been the focus of important and often contentious geological and geodynamic interpretations. However, their age relative to the other components of Archean cratons are often poorly-constrained, introducing significant ambiguity when interpreting their origin and geodynamic significance. The Lewisian Gneiss Complex (LGC) of the northwest Scottish mainland – a high-grade, tonalite-trondhjemite-granodiorite (TTG) terrane that forms part of the North Atlantic Craton (NAC) – contains a number of ultramafic-mafic complexes whose origin and geodynamic significance have remained enigmatic since they were first described. Previous studies have interpreted these complexes as representing a wide-range of geological environments, from oceanic crust, to the sagducted remnants of Archean greenstone belts. These interpretations, which are often critically dependent upon the ages of the complexes relative to the surrounding rocks, have disparate implications for Archean geodynamic regimes (in the NAC and globally). Most previous authors have inferred that the ultramafic-mafic complexes of the LGC pre-date the TTG magmas. This fundamental age relationship is re-evaluated in this investigation through re-mapping of the Geodh’ nan Sgadan Complex (where tonalitic gneiss reportedly cross-cuts mafic rocks) and new mapping of the 7 km2 Ben Strome Complex (the largest ultramafic-mafic complex in the LGC), alongside detailed petrography and spinel mineral chemistry. This new study reveals that, despite their close proximity in the LGC (12 km), the Ben Strome and Geodh’ nan Sgadan Complexes are petrogenetically unrelated, indicating that the LGC (and thus NAC) records multiple temporally and/or petrogenetically distinct phases of ultramafic-mafic Archean magmatism that has been masked by subsequent high-grade metamorphism. Moreover, field observations and spinel mineral chemistry demonstrate that the Ben Strome Complex represents a layered intrusion that was emplaced into a TTG-dominated crust. Further to representing a significant re-evaluation of the LGC’s magmatic evolution, these findings have important implications for the methodologies utilised in deciphering the origin of Archean ultramafic-mafic complexes globally, where material suitable for dating is often unavailable and field relationships are commonly ambiguous.We thank both the Society of Economic Geologists (Graduate Fellowship Award) and Geological Society (Timothy Jefferson Fund) for extremely generous monetary contributions in 2016 and 2017 respectively, which facilitated the (lead author’s) fieldwork that formed basis for this paper

    Fingerprinting fluid source in calcite veins: combining LA-ICP-MS U-Pb calcite dating with trace elements and clumped isotope palaeothermometry

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    Application of geochemical proxies to vein minerals - particularly calcite - can fingerprint the source of fluids controlling various important geological processes from seismicity to geothermal systems. Determining fluid source, e.g. meteoric, marine, magmatic or metamorphic waters, can be challenging when using only trace elements and stable isotopes as different fluids can have overlapping geochemical characteristics, such as δ18O. In this contribution we show that by combining the recently developed LA-ICP-MS U-Pb calcite geochronometer with stable isotopes (including clumped isotope palaeothermometry) and trace element analysis, the fluid source of veins can be more readily determined. Calcite veins hosted in the Devonian Montrose Volcanic Formation at Lunan Bay in the Midland Valley Terrane of Central Scotland were used as a case study. δD values of fluid inclusions in the calcite, and parent fluid δ18O values reconstructed from clumped isotope palaeothermometry, gave values which could represent a range of fluid sources: metamorphic or magmatic fluids, or surface waters which had undergone much fluid-rock interaction. Trace elements showed no distinctive patterns and shed no further light on fluid source. LA-ICP-MS U-Pb dating determined the vein calcite precipitation age – 318±30 Ma – which rule out metamorphic or magmatic fluid sources as no metamorphic or magmatic activity was occurring in the area at this time. The vein fluid source was therefore a surface water (meteoric based on paleogeographic reconstruction) which had undergone significant water-rock interaction. This study highlights the importance of combining the recently developed LA-ICP-MS U-Pb calcite geochronometer with stable isotopes and trace elements to help determine fluid sources of veins, and indeed any geological feature where calcite precipitated from a fluid that may have resided in the crust for a period of time (e.g. fault precipitates or cements)

    The origin(s) and geodynamic significance of Archaean ultramafic-mafic bodies in the mainland Lewisian Gneiss Complex, North Atlantic Craton

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    This is the author accepted manuscript. The final version is available from the Geological Society via the DOI in this recordThe geodynamic regime(s) that predominated during the Archaean remains controversial, with the plethora of competing models largely informed by felsic lithologies. Ultramafic-mafic rocks displaying distinctive geochemical signatures are formed in a range of Phanerozoic geotectonic environments. These rocks have high melting points, making them potentially useful tools for investigating Archaean geodynamic processes in highly metamorphosed regions. We present field mapping, petrography, traditional bulk-rock geochemistry, and platinum-group element geochemistry for 12 ultramafic-mafic bodies in the Lewisian Gneiss Complex (LGC), which is a highly metamorphosed fragment of the North Atlantic Craton in northwest Scotland. Our data indicate that most of these occurrences are layered intrusions emplaced into the tonalite-trondhjemitegranodiorite (TTG)-dominated crust prior to polyphase metamorphism, representing a significant reevaluation of the LGC’s magmatic evolution. Of the others, two remain ambiguous, but one (Loch an Daimh Mor) has some geochemical affinity with abyssal/orogenic peridotites and may represent a fragment of Archaean mantle, although further investigation is required. The ultramafic-mafic bodies in the LGC thus represent more than one type of event/process. Compared with the TTG host rocks, these lithologies may preserve evidence of protolith origin(s), with potential to illuminate tectonic setting(s) and geodynamic regimes of the early Earth

    Isabelle/DOF: Design and Implementation

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    This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record17th International Conference, SEFM 2019 Oslo, Norway, September 18–20, 2019DOF is a novel framework for defining ontologies and enforcing them during document development and evolution. A major goal of DOF is the integrated development of formal certification documents (e. g., for Common Criteria or CENELEC 50128) that require consistency across both formal and informal arguments. To support a consistent development of formal and informal parts of a document, we provide Isabelle/DOF, an implementation of DOF on top of the formal methods framework Isabelle/HOL. A particular emphasis is put on a deep integration into Isabelleâs IDE, which allows for smooth ontology development as well as immediate ontological feedback during the editing of a document. In this paper, we give an in-depth presentation of the design concepts of DOFâs Ontology Definition Language (ODL) and key aspects of the technology of its implementation. Isabelle/DOF is the first ontology language supporting machine-checked links between the formal and informal parts in an LCF-style interactive theorem proving environment. Sufficiently annotated, large documents can easily be developed collabo- ratively, while ensuring their consistency, and the impact of changes (in the formal and the semi-formal content) is tracked automatically.IRT SystemX, Paris-Saclay, Franc

    The impact of supportive nursing care on the needs of men with prostate cancer: a study across seven European countries

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    Background: prostate cancer is for many men a chronic disease with a long life expectancy after treatment. The impact of prostate cancer therapy on men has been well defined, however, explanation of the consequences of cancer treatment has not been modelled against the wider variables of long-term health-care provision. The aim of this study was to explore the parameters of unmet supportive care needs in men with prostate cancer in relation to the experience of nursing care. Methods: a survey was conducted among a volunteer sample of 1001 men with prostate cancer living in seven European countries. Results: at the time of the survey, 81% of the men had some unmet supportive care needs including psychological, sexual and health system and information needs. Logistic regression indicated that lack of post-treatment nursing care significantly predicted unmet need. Critically, men's contact with nurses and/or receipt of advice and support from nurses, for several different aspects of nursing care significantly had an impact on men's outcomes. Conclusion: Unmet need is related not only to disease and treatment factors but is also associated with the supportive care men received. Imperative to improving men's treatment outcomes is to also consider the access to nursing and the components of supportive care provided, especially after therapy

    Trace-element abundances in the shallow lithospheric mantle of the North Atlantic Craton margin: implications for melting and metasomatism beneath Northern Scotland

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    Bulk rock geochemistry and major- and trace-element compositions of clinopyroxene have been determined for three suites of peridotitic mantle xenoliths from the North Atlantic Craton (NAC) in northern Scotland, to establish the magmatic and metasomatic history of subcontinental lithospheric mantle (SCLM) below this region. Spinel lherzolites from the southernmost locality (Streap Com'laidh) have non-NAC mantle compositions, while the two northern xenolith suites (Loch Roag and Rinibar) are derived from the thinned NAC marginal keel. Clinopyroxene compositions have characteristic trace-element signatures which show both 'primary' and 'metasomatic' origins. We use Zr and Hf abundances to identify ancient cryptic refertilization in 'primary' clinopyroxenes. We suggest that Loch Roag and Rinibar peridotite xenoliths represent an ancient Archaean-Palaeoproterozoic SCLM with original depleted cratonic signatures which were overprinted by metasomatism around the time of intrusion of the Scourie Dyke Swarm (∼2.4 Ga). This SCLM keel was preserved during Caledonian orogenesis, although some addition of material and/or metasomatism probably also occurred, as recorded by Rinibar xenoliths. Rinibar and Streap xenoliths were entrained in Permo-Carboniferous magmas and thus were isolated from the SCLM ∼200 Ma before Loch Roag xenoliths (in an Eocene dyke). Crucially, despite their geographical location, lithospheric mantle peridotite samples from Loch Roag show no evidence of recent melting or refertilization during the Palaeogene opening of the Atlantic

    Several Interruptions: 15 Years of the Slade Centre for Electronic Media in Fine Art

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    Seven, sequential solo presentations to celebrate 15 years of the Slade Centre for Electronic Media in Fine Art in 2011. Exhibited: 'Each Long Second' 2006, A0 photocopies, tape. Dimensions: 880 X 850 cms

    Disclosure of Maternal HIV Status to Children: To Tell or Not To Tell . . . That Is the Question

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    HIV-infected mothers face the challenging decision of whether to disclose their serostatus to their children. From the perspective of both mother and child, we explored the process of disclosure, providing descriptive information and examining the relationships among disclosure, demographic variables, and child adjustment. Participants were 23 mothers and one of their noninfected children (9 to 16 years of age). Sixty-one percent of mothers disclosed. Consistent with previous research, disclosure was not related to child functioning. However, children sworn to secrecy demonstrated lower social competence and more externalizing problems. Differential disclosure, which occurred in one-third of the families, was associated with higher levels of depressive and anxiety symptoms. Finally, knowing more than mothers had themselves disclosed was related to child maladjustment across multiple domains. Clinical implications and the need for future research are considered
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