The curious case of an internal pilot in a multicentre randomised trial-time for a rethink?

Acknowledgements The authors would like to acknowledge helpful discussions on this topic held with various colleagues in connection with a variety of projects. Funding No funding was received for this work.Peer reviewedPublisher PD

Letter from Johanna A. Cook to J. R. Brinks, Dec. 4, 1924

Letter sent to a cousin regarding the possibility of getting money from the Pieter Teyler van der Hulst estate, and updates about claims being made by people in Michigan.https://nwcommons.nwciowa.edu/vanderhulst/1000/thumbnail.jp

Conditional versus non-conditional incentives to maximise return of participant completed questionnaires in clinical trials: a cluster randomised study within a trial

Background High participant retention enhances the validity of clinical trials. A monetary incentive can increase retention, but it is not known if when it is provided and if it is conditional matters. We aimed to determine whether there was a difference in the number of follow-up trial questionnaires returned when a monetary (gift voucher) incentive was given to participants at recruitment (non-conditional), compared to informing participants at recruitment that the incentive would be given only once their 14-day daily diary (questionnaire) had been returned (conditional). Method A cluster randomised study within a trial embedded within the Antivirals for influenza-Like Illness, An rCt of Clinical and Cost effectiveness in primary CarE (ALIC4E) Trial. Matched site pairs (GP practices) were randomised using computer-generated random numbers, to either a non-conditional or conditional monetary voucher incentive (only once their 14-day daily diary (questionnaire) had been returned. Sites were matched on previous recruitment levels and practice list size. Analyses were conducted according to randomised groups irrespective of compliance with a two-sided 5% level statistical significance level. The main analysis of the primary outcome (site proportion of diaries returned) was linear regression accounting for site pair (using cluster-robust variance). Additional weighted, paired and non-parametric sensitivity analyses were conducted. Secondary outcomes were the site average number of completed pages, time to return diary, and cost related to the incentive (administration and postage). Results Of the 42 randomised sites (21 for each intervention), only 28 recruited at least one participant with only 10 practice pairs recruiting participants at both constituent sites. Raw diaries return proportions were 0.58 (127/220) and 0.73 (91/125) for non-conditional and conditional incentive groups. Regression analysis adjusted for site pair showed no significant difference in returns, − 0.09, (95% CI, − 0.29, 0.10, p = 0.34); when weighted, there was still no clear difference: 0.15 (95% CI, − 0.02, 0.31, p = 0.07). There was no clear statistical evidence of a difference in time taken to return questionnaires, nor the proportion of pages completed, by the intervention group in the main analyses (all p > 0.05). The conditional incentive was approximately £23 cheaper per diary returned based upon observed data. Conclusion There was no clear evidence of a statistically significant difference in the proportion of participant-completed diaries returned between conditional or non-conditional incentive groups. The time to questionnaire return and completeness of the returned questionnaires were similar in both groups. There was substantial statistical uncertainty in the findings. Some of the sensitivity analyses suggested that a meaningful benefit of a conditional incentive of a magnitude that would be meaningful was plausible. The conditional approach costs less in cash terms

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