Problems with identifying the '8200-year cold event' in terrestrial records of the Atlantic seaboard: a case study from Dooagh, Achill Island, Ireland.

The Northern Hemisphere cooling event 8200 years ago is believed to represent the last known major freshwater pulse into the North Atlantic as a result of the final collapse of the North American Laurentide ice sheet. This pulse of water is generally believed to have occurred independently of orbital variations and provides an analogue for predicted increases in high-latitude precipitation and ice melt as a result of anthropogenically driven future climate change. The precise timing, duration and magnitude of this event, however, are uncertain, with suggestions that the 100-yr meltwater cooling formed part of a longer-term cold period in the early Holocene. Here we undertook a multiproxy, high-resolution investigation of a peat sequence at Dooagh, Achill Island, on the west coast of Ireland, to determine whether the 8200-year cold event impacted upon the terrestrial vegetation immediately downwind of the proposed changes in the North Atlantic. We find clear evidence for an oscillation in the early Holocene using various measures of pollen, indicating a disruption in the vegetation leading to a grassland-dominated landscape, most probably driven by changes in precipitation rather than temperature. Radiocarbon dating was extremely problematic, however, with bulk peat samples systematically too young for the North Atlantic event, suggesting significant contamination from downward root penetration. The sustained disruption to vegetation over hundreds of years at Dooagh indicates the landscape was impacted by a long-term cooling event in the early Holocene, and not the single century length 8200-year meltwater event proposed in many other records in the North Atlantic region.

The Association of Distress and Sleeping Problems With Physicians' Intentions To Change Profession: The Moderating Effect of Job Control

The present study examined whether job control moderated the association between stress indicators (distress and sleeping problems) and intentions to change profession among 2,650 Finnish physicians. Ordinal logistic regression analysis was applied. The authors found that high levels of distress and sleeping problems were associated with higher levels of intentions to change profession, whereas high job control was associated with lower levels of intentions to change profession even after adjusting for the effects of gender, age, and employment sector. In addition, high job control was able to mitigate the positive association that distress and sleeping problems had with intentions to change profession. Our findings highlight the importance of offering more job control to physicians to prevent unnecessary physician turnover.

Solving Decision Problems with Limited Information

We present a new algorithm for exactly solving decision-making problems represented as an influence diagram. We do not require the usual assumptions of no forgetting and regularity, which allows us to solve problems with limited information. The algorithm, which implements a sophisticated variable elimination procedure, is empirically shown to outperform a state-of-the-art algorithm in randomly generated problems of up to 150 variables and 10^64 strategies.

The design and psychometric assessment of a TPB-based questionnaire suitable for use with primary school children

Despite the popularity of the Theory of Planned Behaviour (TPB) a lack of research assessing the efficacy of the model in understanding the health behaviour of children exists, with those studies that have been conducted reporting problems with questionnaire formulation and low to moderate internal consistencies for TPB constructs. The aim of this study was to develop and test a TPB-based measure suitable for use with primary school children aged 9 to 10 years. A mixed method sequential design was employed. In Stage 1, 7 semi-structured focus group discussions (N=56) were conducted to elicit the underlying beliefs specific to tooth brushing. Using content thematic analysis the beliefs were identified and a TPB measure was developed. A repeated measures design was employed in Stage 2 using test re-test reliability analysis in order to assess its psychometric properties. In all, 184 children completed the questionnaire. Test-retest reliabilities support the validity and reliability of the TPB measure for assessing the tooth brushing beliefs of children. Pearson’s product moment correlations were calculated for all of the TPB beliefs, achieving substantial to almost perfect agreement levels. Specifically, a significant relationship between all 10 of the direct and indirect TPB constructs at the 0.01 level was achieved. This paper will discuss the design and development of the measure so could serve as a guide to fellow researchers and health psychologists interested in using theoretical models to investigate the health and well-being of children.

Ultrafast charge-transfer in organic photovoltaic interfaces: geometrical and functionalization effects

Understanding the microscopic mechanisms of electronic excitation in organic photovoltaic cells is a challenging problem in the design of efficient devices capable of performing sunlight harvesting. Here we develop and apply an ab initio approach based on time-dependent density functional theory and Ehrenfest dynamics to investigate photoinduced charge transfer in small organic molecules. Our calculations include mixed quantum–classical dynamics with ions moving classically and electrons quantum mechanically, where no experimental external parameter other than the material geometry is required. We show that the behavior of photocarriers in zinc phthalocyanine (ZnPc) and C60 systems, an effective prototype system for organic solar cells, is sensitive to the atomic orientation of the donor and the acceptor units as well as the functionalization of covalent molecules at the interface. In particular, configurations with the ZnPc molecules facing on C60 facilitate charge transfer between substrate and molecules that occurs within 200 fs. In contrast, configurations where ZnPc is tilted above C60 present extremely low carrier injection efficiency even at longer times as an effect of the larger interfacial potential level offset and higher energetic barrier between the donor and acceptor molecules. An enhancement of charge injection into C60 at shorter times is observed as binding groups connect ZnPc and C60 in a dyad system. Our results demonstrate a promising way of designing and controlling photoinduced charge transfer on the atomic level in organic devices that would lead to efficient carrier separation and maximize device performance.

Common psychology problems in cerebral palsy

Cerebral palsy (CP) refers to a collection of motor impairments which result in abnormal posture and movement following an insult or damage to the developing brain. Psychological adjustment in children with CP is under researched with little population-based or longitudinal data, but there is sufficient evidence to suggest that children with CP are at increased risk for psychological problems. The types of difficulties they experience include emotional, hyperactivity and peer problems with conduct disorder being more prevalent in mildly affected children. The origins of psychological problems in this group are complex but include ‘disease’ and ‘psychosocial’ factors related to having a brain-based disability in the family, as well as other factors that influence adjustment in all children. There are no intervention studies in children with CP aimed at preventing psychological problems or promoting mental wellbeing. However, evidence from other work suggests it is possible to work with the child and family to develop skills, manage symptoms, and build confidence and resilience. Acting as early as possible has been found to be beneficial for bonding, child development and reducing parental anxiety.