24 research outputs found

    CO2 content beneath northern Iceland and the variability of mantle carbon

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geology 46 (2018): 55-58, doi:10.1130/G39413.1.Primitive basalt melt inclusions from Borgarhraun, northern Iceland, display large correlated variations in CO2 and nonvolatile incompatible trace elements (ITEs) such as Nb, Th, Rb, and Ba. The average CO2/ITE ratios of the Borgarhraun melt inclusion population are precisely determined (e.g., CO2/Nb = 391 ± 16; 2σM [two standard errors of the mean], n = 161). These data, along with published data on five other populations of undegassed mid-oceanic ridge basalt (MORB) glasses and melt inclusions, demonstrate that upper mantle CO2/Ba and CO2/Rb are nearly homogeneous, while CO2/Nb and CO2/Th are broadly correlated with long-term indices of mantle heterogeneity reflected in Nd isotopes (143Nd/144Nd) in five of the six regions of the upper mantle examined thus far. Our results suggest that heterogeneous carbon contents of the upper mantle are long-lived features, and that average carbon abundances of the mantle sources of Atlantic MORB are higher by a factor of two than those of Pacific MORB. This observation is correlated with a similar distinction in water contents and trace elements characteristic of subduction fluids (Ba, Rb). We suggest that the upper mantle beneath the younger Atlantic Ocean basin contains components of hydrated and carbonated subduction-modified mantle from prior episodes of Iapetus subduction that were entrained and mixed into the upper mantle during opening of the Atlantic Ocean basin.Maclennan is supported by Natural Environment Research Council grant NE/M000427/1. This research was supported by the Carnegie Institution of Washington

    Relapsed childhood acute lymphoblastic leukemia in the Nordic countries: prognostic factors, treatment and outcome.

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    To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Relapse is the main reason for treatment failure in childhood acute lymphoblastic leukemia. Despite improvements in the up-front therapy, survival after relapse is still relatively poor, especially for high-risk relapses. The aims of this study were to assess outcomes following acute lymphoblastic leukemia relapse after common initial Nordic Society of Paediatric Haematology and Oncology protocol treatment; to validate currently used risk stratifications, and identify additional prognostic factors for overall survival. Altogether, 516 of 2735 patients (18.9%) relapsed between 1992 and 2011 and were included in the study. There were no statistically significant differences in outcome between the up-front protocols or between the relapse protocols used, but an improvement over time was observed. The 5-year overall survival for patients relapsing in the period 2002-2011 was 57.5±3.4%, but 44.7±3.2% (P<0.001) if relapse occurred in the period 1992-2001. Factors independently predicting mortality after relapse included short duration of first remission, bone marrow involvement, age ten years or over, unfavorable cytogenetics, and Down syndrome. T-cell immunophenotype was not an independent prognostic factor unless in combination with hyperleukocytosis at diagnosis. The outcome for early combined pre-B relapses was unexpectedly poor (5-year overall survival 38.0±10.6%), which supports the notion that these patients need further risk adjustment. Although survival outcomes have improved over time, the development of novel approaches is urgently needed to increase survival in relapsed childhood acute lymphoblastic leukemia.Swedish Childhood Cancer Foundation, Barncancerfonde

    Relapsed childhood acute lymphoblastic leukemia in the Nordic countries : prognostic factors, treatment and outcome

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    Relapse is the main reason for treatment failure in childhood acute lymphoblastic leukemia. Despite improvements in the up-front therapy, survival after relapse is still relatively poor, especially for high-risk relapses. The aims of this study were to assess outcomes following acute lymphoblastic leukemia relapse after common initial Nordic Society of Paediatric Haematology and Oncology protocol treatment; to validate currently used risk stratifications, and identify additional prognostic factors for overall survival. Altogether, 516 of 2735 patients (18.9%) relapsed between 1992 and 2011 and were included in the study. There were no statistically significant differences in outcome between the up-front protocols or between the relapse protocols used, but an improvement over time was observed. The 5-year overall survival for patients relapsing in the period 2002-2011 was 57.5 +/- 3.4%, but 44.7 +/- 3.2% (PPeer reviewe

    Relapsed childhood acute lymphoblastic leukemia in the Nordic countries : prognostic factors, treatment and outcome

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    Relapse is the main reason for treatment failure in childhood acute lymphoblastic leukemia. Despite improvements in the up-front therapy, survival after relapse is still relatively poor, especially for high-risk relapses. The aims of this study were to assess outcomes following acute lymphoblastic leukemia relapse after common initial Nordic Society of Paediatric Haematology and Oncology protocol treatment; to validate currently used risk stratifications, and identify additional prognostic factors for overall survival. Altogether, 516 of 2735 patients (18.9%) relapsed between 1992 and 2011 and were included in the study. There were no statistically significant differences in outcome between the up-front protocols or between the relapse protocols used, but an improvement over time was observed. The 5-year overall survival for patients relapsing in the period 2002-2011 was 57.5 +/- 3.4%, but 44.7 +/- 3.2% (PPeer reviewe

    Fluorine in volcanic rocks of Iceland

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    International Symposium on the Activity of Oceanic Volcanoes. Ponta Delgada, 4-9 August 1980.The fluorine content of volcanic rocks from different volcano-tectonic environments in Iceland differs systematically in concert with other petrochemical parameters. The lowest abundance of fluorine (45-220 ppm F) is found in the petrochemically primitive ol-tholeiites of the rift zone. Evolved basalts ranging from ol-tholeiite to qz-tholeiite composition occur in the volcanic centers of the rift zone. These rocks contain 220-450 ppm F, while with alkaline affinities found in volcanic centers outside the rift zone contain up to 1600 ppm F. The variation in fluorine within the different rock suites is believed to reflect varying degree of crustal involvement in their genesis. In the rift zone fluorine chemistry of the basalts is believed to result from mixing with silicic magmas formed by anatexis in the rift zone crust. In the non-rifting volcanic centers the high fluorine results from a partial melting of amphibolite, which is believed to be a residual assemblage from earlier anatexis in the rift zone.info:eu-repo/semantics/publishedVersio

    The minimal structure and motion problems with missing data for 1D retina vision

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    In this paper we investigate the structure and motion problem for calibrated one-dimensional projections of a two-dimensional environment. The theory of one-dimensional cameras are useful in several areas, e.g. within robotics, autonomous guided vehicles, projection of lines in ordinary vision and vision of vehicles undergoing so called planar motion. In a previous paper the structure and motion problem for all cases with non-missing data was classified and solved. Our aim is here to classify all structure and motion problems, even those with missing data, and to solve them. In the classification we introduce the notion of a prime problem. A prime problem is a minimal problem that does not contain a minimal problem as a sub-problem. We further show that there are infinitely many such prime problems. We give solutions to four prime problems, and using the duality of Carlsson these can be extended to solutions of seven prime problems. Finally we give some experimental results based on synthetic data

    Structure and motion problems with occlusions for 1D retina vision

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