Short length scale oxygen isotope heterogeneity in the icelandic mantle: Evidence from plagioclase compositional zones

Using a new high-resolution dataset, this study presents evidence for short length scale 18O/16O heterogeneity in the mantle source region of young (age ≲12 ka bp) Icelandic basalts. The dataset comprises secondary ion mass spectrometry determinations of 18O/16O in single compositional zones of plagioclase crystals from the primitive Borgarhraun flow in northern Iceland, along with trace and major element data from the same zones. The presence of mantle under Iceland with δ18O below typical mid-ocean ridge basalt (MORB) values of ∼5·5 ± 0·3‰ (VSMOW) has previously been disputed, because variability in δ18O in many Icelandic basalts is also known to be caused by the interaction of basaltic melts with crustal lithologies that have been altered by low-δ18O meteoric water. Primitive basalt flows, such as Borgarhraun, and their macrocrysts are the most likely candidates to retain a mantle δ18O signature. However, the role of crustal processes in generating the low δ18O in olivine crystals from these flows has not unequivocally been ruled out. By making intra-crystal analyses in Borgarhraun plagioclase it has been possible in this study to obtain a detailed record of the chemical and isotopic compositions of the melts that crystallized the plagioclase zones. The variability observed in trace element compositions of the early crystallized anorthitic plagioclase zones (80·9–89·4 mol % anorthite) is firstly shown to arise from melt compositional variability, and equilibrium melt concentrations of Sr, La and Y are then calculated from the crystal concentrations of these elements using carefully selected partition coefficients. The ranges of incompatible trace element ratios (La/Y, Sr/Y) in these equilibrium melts reflect a range of compositions of fractional mantle melts, a result that is in agreement with previous proposals for the cause of variability in trace element indices of Borgarhraun olivine-hosted melt inclusions and clinopyroxene compositional zones. Correlations observed between La/Y and Sr/Y in the melts in equilibrium with the Borgarhraun plagioclase zones and the δ18O of these zones therefore support the hypothesis that the mantle under Iceland is heterogeneous in 18O/16O. Such correlations have not previously been observed in intra-crystal data from Iceland, and provide strong evidence that mantle material with abnormally low δ18O may exist in the form of readily fusible heterogeneities alongside ambient mantle with MORB-like δ18O (≈+5·5‰) on a length scale of <100 km. The lowest δ18O of plagioclase that is attributed to a mantle origin in this study is 4·5 ± 0·4‰, equating to a melt equivalent value of 4·3 ± 0·5‰ or an olivine equivalent value of 3·8 ± 0·5‰.This work was supported by a Natural Environment Research Council studentship to B.W. (NE/F007183/1), a Natural Environment Research Council young investigator grant to J.M. (NE/E001254/1) and a Natural Environment Research Council Ion Microprobe Facility award (IMF 365/1008).This is the final published version. It first appeared at http://petrology.oxfordjournals.org/content/55/12/2537.abstract

Systematic review of perioperative and quality-of-life outcomes following surgical management of localised renal cancer

UCAN Cancer Charity (www.ucanhelp.org.uk) and MacMillan Cancer Charity (www.macmillan.org.uk) helped design and conduct the study.Peer reviewedPostprin

Mitoxantrone is superior to doxorubicin in a multiagent weekly regimen for patients older than 60 with high-grade lymphoma: results of a BNLI randomized trial of PAdriaCEBO versus PMitCEBO

A prospective, multicenter, randomized trial was undertaken to compare the efficacy and toxicity of adriamycin with mitoxantrone within a 6-drug combination chemotherapy regimen for elderly patients (older than 60 years) with high-grade non-Hodgkin lymphoma (HGL) given for a minimum of 8 weeks. A total of 516 previously untreated patients aged older than 60 years were randomized to receive 1 of 2 anthracycline-containing regimens: adriamycin, 35 mg/m2 intravenously (IV) on day 1 (n = 259), or mitoxantrone, 7 mg/m2 IV on day 1 (n = 257); with prednisolone, 50 mg orally on days 1 to 14; cyclophosphamide, 300 mg/m2 IV on day 1; etoposide, 150 mg/m2 IV on day 1; vincristine, 1.4 mg/m2 IV on day 8; and bleomycin, 10 mg/m2 IV on day 8. Each 2-week cycle was administered for a minimum of 8 weeks in the absence of progression. Forty-three patients were ineligible for analysis. The overall and complete remission rates were 78% and 60% for patients receiving PMitCEBO and 69% and 52% for patients receiving PAdriaCEBO (P = .05, P = .12, respectively). Overall survival was significantly better with PMitCEBO than PAdriaCEBO (P = .0067). However, relapse-free survival was not significantly different (P = .16). At 4 years, 28% of PAdriaCEBO patients and 50% of PMitCEBO patients were alive (P = .0001). Ann Arbor stage III/IV, World Health Organization performance status 2-4, and elevated lactate dehydrogenase negatively influenced overall survival from diagnosis. In conclusion, the PMitCEBO 8-week combination chemotherapy regimen offers high response rates, durable remissions, and acceptable toxicity in elderly patients with HGL

Using shared goal setting to improve access and equity: a mixed methods study of the Good Goals intervention

Background: Access and equity in children’s therapy services may be improved by directing clinicians’ use of resources toward specific goals that are important to patients. A practice-change intervention (titled ‘Good Goals’) was designed to achieve this. This study investigated uptake, adoption, and possible effects of that intervention in children’s occupational therapy services. Methods: Mixed methods case studies (n = 3 services, including 46 therapists and 558 children) were conducted. The intervention was delivered over 25 weeks through face-to-face training, team workbooks, and ‘tools for change’. Data were collected before, during, and after the intervention on a range of factors using interviews, a focus group, case note analysis, routine data, document analysis, and researchers’ observations. Results: Factors related to uptake and adoptions were: mode of intervention delivery, competing demands on therapists’ time, and leadership by service manager. Service managers and therapists reported that the intervention: helped therapists establish a shared rationale for clinical decisions; increased clarity in service provision; and improved interactions with families and schools. During the study period, therapists’ behaviours changed: identifying goals, odds ratio 2.4 (95% CI 1.5 to 3.8); agreeing goals, 3.5 (2.4 to 5.1); evaluating progress, 2.0 (1.1 to 3.5). Children’s LoT decreased by two months [95% CI −8 to +4 months] across the services. Cost per therapist trained ranged from £1,003 to £1,277, depending upon service size and therapists’ salary bands. Conclusions: Good Goals is a promising quality improvement intervention that can be delivered and adopted in practice and may have benefits. Further research is required to evaluate its: (i) impact on patient outcomes, effectiveness, cost-effectiveness, and (ii) transferability to other clinical contexts

A randomised trial comparing three Delphi feedback strategies found no evidence of a difference in a setting with high initial agreement

Peer reviewedPostprintPostprintPostprintPostprintPostprintPostprintPostprintPostprintPostprintPostprintPostprin

Development without deforestation

The conservation projects managed by the United Nations Development Programme (UNDP) in Brazil are underpinned by a strong element of inclusive local development, consisting of innovative initiatives regarding the sustainable use of biodiversity. There are many examples of projects in Mangrove, Caatinga and Cerrado areas, which conciliate the production of goods and environmental services with the generation of jobs, income and an increase in life quality. It is always an enormous challenge to assure opportunities to the most vulnerable populations living in areas characterised by a great expansion of agricultural commodities production and cattle ranching, while respecting people's livelihoods and protecting the environment. [...

Effects of present-day deglaciation in Iceland on mantle melt production rates

Ongoing deglaciation in Iceland not only causes uplift at the surface but also increases magma production at depth due to decompression of the mantle. Here we study glacially induced decompression melting using 3‐D models of glacial isostatic adjustment in Iceland since 1890. We find that the mean glacially induced pressure rate of change in the mantle increases melt production rates by 100–135%, or an additional 0.21–0.23 km3 of magma per year beneath Iceland. Approximately 50% of this melt is produced underneath central Iceland. The greatest volumetric increase is found directly beneath Iceland's largest ice cap, Vatnajökull, colocated with the most productive volcanoes. Our models of the effect of deglaciation on mantle melting predict a significantly larger volumetric response than previous models which only considered the effect of deglaciation of Vatnajökull, and only mantle melting directly below Vatnajökull. Although the ongoing deglaciation significantly increases the melt production rate, the increase in melt supply rate at the base of the lithosphere is delayed and depends on the melt ascent velocity through the mantle. Assuming that 25% of the melt reaches the surface, the upper limit on our deglaciation‐induced melt estimates for central Iceland would be equivalent to an eruption the size of the 2010 Eyjafjallajökull summit eruption every seventh year

A core outcome set for localised prostate cancer effectiveness trials : protocol for a systematic review of the literature and stakeholder involvement through interviews and a Delphi survey

Acknowledgements We would like to thank Professor Craig Ramsay, Professor Luke Vale, and Professor Vikki Entwistle for their comments on earlier drafts of the protocol. This study is funded by the Cancer Research Aberdeen and North East Scotland (CRANES) charity. Paula Williamson would like to acknowledge funding from the European Union Seventh Framework Programme (FP7/2007-2013, FP7/2007-2011) under grant agreement number 305081 for the COMET initiative, which provided support for this work.Peer reviewedPublisher PD