DIETARY PATTERNS IN STREAM- AND LAKE-DWELLING POPULATIONS OF AUSTROPOTAMOBIUS PALLIPES

White-clawed crayfish (Austropotamobius pallipes) are widespread in Ireland in both running and standing water, although stream-dwelling in much of their range elsewhere. A detailed comparative study of a lake and a stream population demonstrated that diets changed with crayfish size from feeding on entomostracans to a predominance of aquatic macrophytes and terrestrial vegetation. However, carnivory remained important at all sizes: Gammarids were a significant component in larger lake crayfish and in all sizes of stream crayfish. Fish increased in importance with crayfish size. A. pallipes thus appears more carnivorous than some other European and American crayfish. The extent to which this is related to habitat is discussed

Water service delivery challenges in a small South African municipality: Identifying and exploring key elements and relationships in a complex social-ecological system

South Africa is a developing country undergoing social and ecological transformation. Water service delivery (i) exemplifies the challenge of improvement and transformation towards a more socially and ecologically just situation, and (ii) can usefully be viewed as a complex social-ecological system (C-SES) in the search for ‘just transitions’. Household water security problems associated with water service delivery in South Africa are recognisably intractable, multi-scaled, comprising many actors and elements and having no single solution. There is a global and South African trend towards systemic approaches to addressing such complex water challenges. However, the steps required to take a systemic approach are seldom explicit. This paper presents the analytical process of defining boundaries, identifying elements and exploring relationships between elements as the foundational step in a study of the Makana Local Municipality water service delivery C-SES in the Eastern Cape Province of South Africa. The resulting narrative and heuristics provide a clear systemic basis from which to research the emergence, practice and social learning process of a civil society organisation (Water for Dignity) seeking to confront water service delivery issues in the Makana Local Municipality.Keywords: complex adaptive systems, systems inquiry, household water service delivery, civil society organisatio

Sensitivity of nonlinear photoionization to resonance substructure in collective excitation

Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources

Somatic Genome Editing: Technical Challenges and Ethical Appraisal

The ability to modify the DNA sequences with molecular tools that employ nucleases has made it possible to edit genomes. Somatic genome editing is the procedure to alter the genome of somatic cells, making the changes introduced into the nucleotide sequence not inheritable. Powerful tools have been developed for therapeutic purposes to correct monogenic inherited disorders that often cause premature death and for which effective treatment options are not available. To ensure positive impact and minimise potential harms of these techniques, require to understand their limits in addition to apply values and principles that guide their use. This study reviews technical challenges of genome editing and appraises the Ethics of its application

EUV ionization of pure He nanodroplets: Mass-correlated photoelectron imaging, Penning ionization and electron energy-loss spectra

The ionization dynamics of pure He nanodroplets irradiated by EUV radiation is studied using Velocity-Map Imaging PhotoElectron-PhotoIon COincidence (VMI-PEPICO) spectroscopy. We present photoelectron energy spectra and angular distributions measured in coincidence with the most abundant ions He+, He2+, and He3+. Surprisingly, below the autoionization threshold of He droplets we find indications for multiple excitation and subsequent ionization of the droplets by a Penning-like process. At high photon energies we evidence inelastic collisions of photoelectrons with the surrounding He atoms in the droplets

Limitations of predicting substrate classes on a sedimentary complex but morphologically simple seabed

The ocean floor, its species and habitats are under pressure from various human activities. Marine spatial planning and nature conservation aim to address these threats but require sufficiently detailed and accurate maps of the distribution of seabed substrates and habitats. Benthic habitat mapping has markedly evolved as a discipline over the last decade, but important challenges remain. To test the adequacy of current data products and classification approaches, we carried out a comparative study based on a common dataset of multibeam echosounder bathymetry and backscatter data, supplemented with groundtruth observations. The task was to predict the spatial distribution of five substrate classes (coarse sediments, mixed sediments, mud, sand, and rock) in a highly heterogeneous area of the south-western continental shelf of the United Kingdom. Five different supervised classification methods were employed, and their accuracy estimated with a set of samples that were withheld. We found that all methods achieved overall accuracies of around 50%. Errors of commission and omission were acceptable for rocky substrates, but high for all sediment types. We predominantly attribute the low map accuracy regardless of mapping approach to inadequacies of the selected classification system, which is required to fit gradually changing substrate types into a rigid scheme, low discriminatory power of the available predictors, and high spatial complexity of the site relative to the positioning accuracy of the groundtruth equipment. Some of these issues might be alleviated by creating an ensemble map that aggregates the individual outputs into one map showing the modal substrate class and its associated confidence or by adopting a quantitative approach that models the spatial distribution of sediment fractions. We conclude that further incremental improvements to the collection, processing and analysis of remote sensing and sample data are required to improve map accuracy. To assess the progress in benthic habitat mapping we propose the creation of benchmark datasets

Observing Interprofessional Simulation

© 2019, Springer Nature Switzerland AG. This chapter has a particular focus on the observers’ role in simulation-based learning activities. Simulation-based learning is often organised so that participants rotates between active participation in the scenario and participation as observers. The research examples provided show that the conditions for learning are related to the locations where and the ways the observers are situated, and to how the instructions to the observers are formulated. Arguments are put forward that the observers’ role in simulation has unexploited potential for developing skills of noticing

Collaborative governance in a primary health care partnership in Papua New Guinea

Introduction: Collaboration in primary health care is recommended to achieve global health goals. Public-private partnerships (PPP) are one means of collaboration. Our study examined collaboration in a case study PPP for primary health care in Western Province, Papua New Guinea (PNG). Methods: Interviews with key informants involved in the PPP were conducted and key programme documents were reviewed. Data were coded and deductively analysed using the collaborative governance model developed by Emerson, Nabatchi and Balogh. Results: The key features of the case study PPP that were highlighted by the collaborative governance model were: identification of partners, trust, procedural arrangements, and leadership. Discussion: We identified four lessons of significance in the practical establishment and implementation of a partnership in a complex and challenging setting such as PNG: the need to (i) prioritise in-person collaboration and communication, (ii) engage dynamic individuals to lead the partnership, (iii) encourage relationships across all sectors and actors, and (iv) remain flexible and adapt to local cultural and context. Conclusion: Collaborative governance offers a practical framework to understand, assess and strengthen collaboration in multi-stakeholder partnerships in the health sector

Transformation Pathways of Silica under High Pressure

Concurrent molecular dynamics simulations and ab initio calculations show that densification of silica under pressure follows a ubiquitous two-stage mechanism. First, anions form a close-packed sub-lattice, governed by the strong repulsion between them. Next, cations redistribute onto the interstices. In cristobalite silica, the first stage is manifest by the formation of a metastable phase, which was observed experimentally a decade ago, but never indexed due to ambiguous diffraction patterns. Our simulations conclusively reveal its structure and its role in the densification of silica.Comment: 14 pages, 4 figure

Structural stability of Fe5Si3 and Ni2Si studied by high-pressure x-ray diffraction and ab initio total-energy calculations

We performed high-pressure angle dispersive x-ray diffraction measurements on Fe5Si3 and Ni2Si up to 75 GPa. Both materials were synthesized in bulk quantities via a solid-state reaction. In the pressure range covered by the experiments, no evidence of the occurrence of phase transitions was observed. On top of that, Fe5Si3 was found to compress isotropically, whereas an anisotropic compression was observed in Ni2Si. The linear incompressibility of Ni2Si along the c-axis is similar in magnitude to the linear incompressibility of diamond. This fact is related to the higher valence-electron charge density of Ni2Si along the c-axis. The observed anisotropic compression of Ni2Si is also related to the layered structure of Ni2Si where hexagonal layers of Ni2+ cations alternate with graphite-like layers formed by (NiSi)2- entities. The experimental results are supported by ab initio total-energy calculations carried out using density functional theory and the pseudopotential method. For Fe5Si3, the calculations also predicted a phase transition at 283 GPa from the hexagonal P63/mcm phase to the cubic structure adopted by Fe and Si in the garnet Fe5Si3O12. The room-temperature equations of state for Fe5Si3 and Ni2Si are also reported and a possible correlation between the bulk modulus of iron silicides and the coordination number of their minority element is discussed. Finally, we report novel descriptions of these structures, in particular of the predicted high-pressure phase of Fe5Si3 (the cation subarray in the garnet Fe5Si3O12), which can be derived from spinel Fe2SiO4 (Fe6Si3O12).Comment: 44 pages, 13 figures, 3 Table