A statistical comparison of the optical/UV and X-ray afterglows of gamma-ray bursts using the Swift Ultraviolet Optical and X-ray Telescopes

We present the systematic analysis of the Ultraviolet/Optical Telescope (UVOT) and X-ray Telescope (XRT) light curves for a sample of 26 Swift gamma-ray bursts (GRBs). By comparing the optical/UV and X-ray light curves, we found that they are remarkably different during the first 500 s after the Burst Alert Telescope trigger, while they become more similar during the middle phase of the afterglow, i.e. between 2000 and 20 000 s. If we take literally the average properties of the sample, we find that the mean temporal indices observed in the optical/UV and X-rays after 500 s are consistent with a forward-shock scenario, under the assumptions that electrons are in the slow cooling regime, the external medium is of constant density and the synchrotron cooling frequency is situated between the optical/UV and X-ray observing bands. While this scenario describes well the averaged observed properties, some individual GRB afterglows require different or additional assumptions, such as the presence of late energy injection. We show that a chromatic break (a break in the X-ray light curve that is not seen in the optical) is present in the afterglows of three GRBs and demonstrate evidence for chromatic breaks in a further four GRBs. The average properties of these breaks cannot be explained in terms of the passage of the synchrotron cooling frequency through the observed bands, nor a simple change in the external density. It is difficult to reconcile chromatic breaks in terms of a single component outflow and instead, more complex jet structure or additional emission components are required

A review of RCTs in four medical journals to assess the use of imputation to overcome missing data in quality of life outcomes

Peer reviewedPublisher PD

Eye Movements Predict Recollective Experience

Previously encountered stimuli can bring to mind a vivid memory of the episodic context in which the stimulus was first experienced ("remembered'' stimuli), or can simply seem familiar ("known'' stimuli). Past studies suggest that more attentional resources are required to encode stimuli that are subsequently remembered than known. However, it is unclear if the attentional resources are distributed differently during encoding and recognition of remembered and known stimuli. Here, we record eye movements while participants encode photos, and later while indicating whether the photos are remembered, known or new. Eye fixations were more clustered during both encoding and recognition of remembered photos relative to known photos. Thus, recognition of photos that bring to mind a vivid memory for the episodic context in which they were experienced is associated with less distributed overt attention during encoding and recognition. The results suggest that remembering is related to encoding of a few distinct details of a photo rather than the photo as a whole. In turn, during recognition remembering may be trigged by enhanced memory for the salient details of the photos

Age-dependent changes in clock neuron structural plasticity and excitability are associated with a decrease in circadian output behaviour and sleep

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordAgeing has significant effects on circadian behaviour across a wide variety of species, but the underlying mechanisms are poorly understood. Previous work has demonstrated the age-dependent decline in behavioural output in the model organism Drosophila. We demonstrate this age-dependent decline in circadian output is combined with changes in daily activity of Drosophila. Ageing also has a large impact on sleep behaviour, significantly increasing sleep duration whilst reducing latency. We used electrophysiology to record from large ventral lateral neurons (l-LNv) of the Drosophila circadian clock, finding a significant decrease in input resistance with age, but no significant changes in spontaneous electrical activity or membrane potential. We propose this change contributes to observed behavioural and sleep changes in light-dark conditions. We also demonstrate a reduction in the daily plasticity of the architecture of the small ventral lateral neurons (s-LNv), likely underlying the reduction in circadian rhythmicity during ageing. These results provide further insights into the effect of ageing on circadian biology, demonstrating age-related changes in electrical activity in conjunction with the decline in behavioural outputs.Wellcome TrustLeverhulme TrustEngineering and Physical Sciences Research Council (EPSRC

Economics methods in Cochrane systematic reviews of health promotion and public health related interventions.

Peer reviewedPublisher PD

Ageing and entrepreneurial preferences

Previous research on age and entrepreneurship assumed homogeneity and downplayed age-related differences in the motives and aims underlying enterprising behaviour. We argue that the heterogeneity of entrepreneurship influences how the level of entrepreneurial activity varies with age. Using a sample of 2566 respondents from 27 European countries we show that entrepreneurial activity increases almost linearly with age for individuals who prefer to only employ themselves (self-employers), whereas it increases up to a critical threshold age (late 40s) and decreases thereafter for those who aspire to hire workers (owner-managers). Age has a considerably smaller effect on entrepreneurial behaviour for those who do not prefer self-employment but are pushed into it by lack of alternative employment opportunities (reluctant entrepreneurs). Our results question the conventional wisdom that entrepreneurial activity declines with age and suggest that effective responses to demographic changes require policy makers to pay close attention to the heterogeneity of entrepreneurial preferences

Intermittent auscultation versus continuous fetal monitoring: Exploring factors that influence birthing unit nurses' fetal surveillance practice using theoretical domains framework

Background: Intermittent Auscultation (IA) is the recommended method of fetal surveillance for healthy women in labour. However, the majority of women receive continuous electronic monitoring. We used the Theoretical Domains Framework (TDF) to explore the views of Birthing Unit nurses about using IA as their primary method of fetal surveillance for healthy women in labour. Methods: Using a semi-structured interview guide, we interviewed a convenience sample of birthing unit nurses throughout Ontario, Canada to elicit their views about fetal surveillance. Interviews were recorded and transcribed verbatim. Transcripts were content analysed using the TDF and themes were framed as belief statements. Domains potentially key to changing fetal surveillance behaviour and informing intervention design were identified by noting the frequencies of beliefs, content, and their reported influence on the use of IA Results: We interviewed 12 birthing unit nurses. Seven of the 12 TDF domains were perceived to be key to changing birthing unit nurses' behaviour The nurses reported that competing tasks, time constraints and the necessity to multitask often limit their ability to perform IA (domains Beliefs about capabilities; Environmental context and resources). Some nurses noted the decision to use IA was something that they consciously thought about with every patient while others stated it their default decision as long as there were no risk factors (Memory, attention and decision processes, Nature of behaviour). They identified positive consequences (e.g. avoid unnecessary interventions, mother-centered care) and negative consequences of using IA (e.g. legal concerns) and reported that the negative consequences can often outweigh positive consequences (Beliefs about consequences). Some reported that hospital policies and varying support from care teams inhibited their use of IA (Social influences), and that support from the entire team and hospital management would likely increase their use (Social influences; Behavioural regulation). Conclusion: We identified potential influences on birthing unit nurses' use of IA as their primary method of fetal surveillance. These beliefs suggest potential targets for behaviour change interventions to promote IA use