Perspectives of ammunition users on the use of lead ammunition and its potential impacts on wildlife and humans

This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: All data supporting the results in this paper are available from Zenodo (digital repository): https://zenodo.org/record/2653514#.XMbMXKbsZD8 (Newth et al., 2019).1. Recent national and international policy initiatives have aimed to reduce the exposure of humans and wildlife to lead from ammunition. Despite restrictions, in the UK, lead ammunition remains the most widespread source of environmental lead contamination to which wildlife may be exposed. 2. The risks arising from the use of lead ammunition and the measures taken to mitigate these have prompted intense and sometimes acrimonious discussion between stakeholder groups, including those advancing the interests of shooting, wildlife conservation, public health and animal welfare. 3. However, relatively little is known of the perspectives of individual ammunition users, despite their role in adding lead to the environment and their pivotal place in any potential changes to practice. Using Q‐methodology, we identified the perspectives of ammunition users in the UK on lead ammunition in an effort to bring forward evidence from these key stakeholders. 4. Views were characterised by two statistically and qualitatively distinct perspectives: (a) Open to change—comprised ammunition users that refuted the view that lead ammunition is not a major source of poisoning in wild birds, believed that solutions to reduce the risks of poisoning are needed, were happy to use non‐lead alternatives and did not feel that the phasing out of lead shot would lead to the demise of shooting; and (b) Status quo—comprised ammunition users who did not regard lead poisoning as a major welfare problem for wild birds, were ambivalent about the need for solutions and felt that lead shot is better than steel at killing and not wounding an animal. They believed opposition to lead ammunition was driven more by a dislike of shooting than evidence of any harm. 5. Adherents to both perspectives agreed that lead is a toxic substance. There was consensus that involvement of stakeholders from all sides of the debate was desirable and that to be taken seriously by shooters, information about lead poisoning should come from the shooting community

The implausibility of ‘usual care’ in an open system: sedation and weaning practices in Paediatric Intensive Care Units (PICUs) in the United Kingdom (UK)

Background: The power of the randomised controlled trial depends upon its capacity to operate in a closed system whereby the intervention is the only causal force acting upon the experimental group and absent in the control group, permitting a valid assessment of intervention efficacy. Conversely, clinical arenas are open systems where factors relating to context, resources, interpretation and actions of individuals will affect implementation and effectiveness of interventions. Consequently, the comparator (usual care) can be difficult to define and variable in multi-centre trials. Hence outcomes cannot be understood without considering usual care and factors that may affect implementation and impact on the intervention. Methods: Using a fieldwork approach, we describe PICU context, ‘usual’ practice in sedation and weaning from mechanical ventilation, and factors affecting implementation prior to designing a trial involving a sedation and ventilation weaning intervention. We collected data from 23 UK PICUs between June and November 2014 using observation, individual and multi-disciplinary group interviews with staff. Results: Pain and sedation practices were broadly similar in terms of drug usage and assessment tools. Sedation protocols linking assessment to appropriate titration of sedatives and sedation holds were rarely used (9 % and 4 % of PICUs respectively). Ventilator weaning was primarily a medical-led process with 39 % of PICUs engaging senior nurses in the process: weaning protocols were rarely used (9 % of PICUs). Weaning methods were variably based on clinician preference. No formal criteria or use of spontaneous breathing trials were used to test weaning readiness. Seventeen PICUs (74 %) had prior engagement in multi-centre trials, but limited research nurse availability. Barriers to previous trial implementation were intervention complexity, lack of belief in the evidence and inadequate training. Facilitating factors were senior staff buy-in and dedicated research nurse provision. Conclusions: We examined and identified contextual and organisational factors that may impact on the implementation of our intervention. We found usual practice relating to sedation, analgesia and ventilator weaning broadly similar, yet distinctively different from our proposed intervention, providing assurance in our ability to evaluate intervention effects. The data will enable us to develop an implementation plan; considering these factors we can more fully understand their impact on study outcomes

Critical dynamics in the evolution of stochastic strategies for the iterated Prisoner's Dilemma

The observed cooperation on the level of genes, cells, tissues, and individuals has been the object of intense study by evolutionary biologists, mainly because cooperation often flourishes in biological systems in apparent contradiction to the selfish goal of survival inherent in Darwinian evolution. In order to resolve this paradox, evolutionary game theory has focused on the Prisoner's Dilemma (PD), which incorporates the essence of this conflict. Here, we encode strategies for the iterated Prisoner's Dilemma (IPD) in terms of conditional probabilities that represent the response of decision pathways given previous plays. We find that if these stochastic strategies are encoded as genes that undergo Darwinian evolution, the environmental conditions that the strategies are adapting to determine the fixed point of the evolutionary trajectory, which could be either cooperation or defection. A transition between cooperative and defective attractors occurs as a function of different parameters such a mutation rate, replacement rate, and memory, all of which affect a player's ability to predict an opponent's behavior.Comment: 27 pages, including supplementary information. 5 figures, 4 suppl. figures. Version accepted for publication in PLoS Comp. Bio

Evolution of the vertebrate jaw: comparative embryology and molecular developmental biology reveal the factors behind evolutionary novelty

It is generally believed that the jaw arose through the simple transformation of an ancestral rostral gill arch. The gnathostome jaw differentiates from Hox-free crest cells in the mandibular arch, and this is also apparent in the lamprey. The basic Hox code, including the Hox-free default state in the mandibular arch, may have been present in the common ancestor, and jaw patterning appears to have been secondarily constructed in the gnathostomes. The distribution of the cephalic neural crest cells is similar in the early pharyngula of gnathostomes and lampreys, but different cell subsets form the oral apparatus in each group through epithelial–mesenchymal interactions: and this heterotopy is likely to have been an important evolutionary change that permitted jaw differentiation. This theory implies that the premandibular crest cells differentiate into the upper lip, or the dorsal subdivision of the oral apparatus in the lamprey, whereas the equivalent cell population forms the trabecula of the skull base in gnathostomes. Because the gnathostome oral apparatus is derived exclusively from the mandibular arch, the concepts ‘oral’ and ‘mandibular’ must be dissociated. The ‘lamprey trabecula’ develops from mandibular mesoderm, and is not homologous with the gnathostome trabecula, which develops from premandibular crest cells. Thus the jaw evolved as an evolutionary novelty through tissue rearrangements and topographical changes in tissue interactions