Effects of zinc on microalgal biofilms in intertidal and subtidal habitats

Microalgal biofilms are sensitive to environmental conditions. Impacts of contaminants on assemblages of marine biofilm are often investigated in laboratories or in mesocosms. Such experiments are rarely representative of the effects of contaminants on biofilms under natural conditions. Studies in field situations, with enough power to detect impacts, are necessary to develop a better understanding of the effects of contaminants on ecological processes. Metals are a common contaminant of marine systems and can cause disturbances to assemblages. Using a new technique to experimentally deliver contaminants to microalgal assemblages, hypotheses were tested regarding the effects of zinc on microalgal biofilms growing on settlement panels in subtidal and intertidal habitats. PAM fluorometry was used to assess the amount and physiological state of biofilms on panels. Control panels deployed for 1 month in each habitat had significantly greater amounts of biofilm than those exposed to zinc. After deployment for 3 months, the results varied with location. The observed effects on the biofilm did not, however, cause significant changes in the macro-invertebrate assemblages that developed on the panels

Inlet protein aggregation: a new mechanism for lubricating film formation with model synovial fluids.

This paper reports a fundamental study of lubricant film formation with model synovial fluid components (proteins) and bovine serum (BS). The objective was to investigate the role of proteins in the lubrication process. Film thickness was measured by optical interferometry in a ball-on-disc device (mean speed range of 2-60 mm/s). A commercial cobalt-chromium (CoCrMo) metal femoral head was used as the stationary component. The results for BS showed complex time-dependent behaviour, which was not representative of a simple fluid. After a few minutes sliding BS formed a thin adherent film of 10-20 nm, which was attributed to protein absorbance at the surface. This layer was augmented by a hydrodynamic film, which often increased at slow speeds. At the end of the test deposited surface layers of 20-50 nm were measured. Imaging of the contact showed that at slow speeds an apparent 'phase boundary' formed in the inlet just in front of the Hertzian zone. This was associated with the formation of a reservoir of high-viscosity material that periodically moved through the contact forming a much thicker film. The study shows that proteins play an important role in the film-forming process and current lubrication models do not capture these mechanisms

Cladding strategies for building-integrated photovoltaics

Photovoltaic cladding on the surfaces of commercial buildings has the potential for considerable reductions in carbon emissions due to embedded renewable power generation displacing conventional power utilization. In this paper, a model is described for the optimization of photovoltaic cladding densities on commercial building surfaces. The model uses a modified form of the ‘fill factor’ method for photovoltaic power supply coupled to new regression-based procedures for power demand estimation. An optimization is included based on a defined ‘mean index of satisfaction’ for matched power supply and demand (i.e., zero power exportation to the grid). The mean index of satisfaction directly translates to the reduction in carbon emission that might be expected over conventional power use. On clear days throughout the year, reductions of conventional power use of at least 60% can be achieved with an optimum cladding pattern targeted to lighting and small power load demands

Switched wave packets: A route to nonperturbative quantum control

The dynamic Stark effect due to a strong nonresonant but nonionizing laser field provides a route to quantum control via the creation of novel superposition states. We consider the creation of a field-free "switched" wave packet through adiabatic turn-on and sudden turn-off of a strong dynamic Stark interaction. There are two limiting cases for such wave packets. The first is a Raman-type coupling, illustrated by the creation of field-free molecular axis alignment. An experimental demonstration is given. The second case is that of dipole-type coupling, illustrated by the creation of charge localization in an array of quantum wells

Transition between educational sectors and discontinuities of ICT resource and pedagogy

Technologically supported education has introduced benefits but also challenges to the transition across school levels of education. While resolving some traditional issues, these technologies have in some instances created a new set of discontinuities at both the resource and pedagogic level. These discontinuities arise due to variance between primary and secondary school access and practice, and also between pupils' experiences of access and practice at previous institutions. In this paper evidence is presented from interview, questionnaire, and classroom observation data collected from 48 schools during two projects investigating the impact of high-speed Internet access (broadband) in English schools. Findings indicate that schools offer different levels of access to technology, and also different activities when using technology facilities. While differences in practice have always been present across and within levels of education, the introduction of high-speed Internet access has increased the gap between those using the technology as an add-on to existing resources and those embedding the technological facilities into the fabric of the learning environment. A key issue explored is the impact of the discontinuity that occurs when primary (elementary school) education becomes technically richer than partner secondary (high school) institutions

Pain management for chronic musculoskeletal conditions : the development of an evidence-based and theory-informed pain self-management course

Objective: To devise and test a self-management course for chronic pain patients based on evidence and underpinned by theory using the Medical Research Council (MRC) framework for developing complex interventions. Design: We used a mixed method approach. We conducted a systematic review of the effectiveness of components and characteristics of pain management courses. We then interviewed chronic pain patients who had attended pain and self-management courses. Behavioural change theories were mapped onto our findings and used to design the intervention. We then conducted a feasibility study to test the intervention. Setting: Primary care in the inner city of London, UK. Participants: Adults (18 years or older) with chronic musculoskeletal pain. Outcomes: Related disability, quality of life, coping, depression, anxiety, social integration and healthcare resource use. Results: The systematic reviews indicated that group-based courses with joint lay and healthcare professional leadership and that included a psychological component of short duration (<8 weeks) showed considerable promise. The qualitative research indicated that participants liked relaxation, valued social interaction and course location, and that timing and good tutoring were important determinants of attendance. We used behavioural change theories (social learning theory and cognitive behaviour approaches (CBA)) to inform course content. The course addressed: understanding and accepting pain, mood and pain, unhelpful thoughts and behaviour, problem solving, goal setting, action planning, movement, relaxation and social integration/reactivation. Attendance was 85%; we modified the recruitment of patients, the course and the training of facilitators as a result of testing. Conclusions: The MRC guidelines were helpful in developing this intervention. It was possible to train both lay and non-psychologists to facilitate the courses and deliver CBA. The course was feasible and well received

Universal quantum computation by discontinuous quantum walk

Quantum walks are the quantum-mechanical analog of random walks, in which a quantum `walker' evolves between initial and final states by traversing the edges of a graph, either in discrete steps from node to node or via continuous evolution under the Hamiltonian furnished by the adjacency matrix of the graph. We present a hybrid scheme for universal quantum computation in which a quantum walker takes discrete steps of continuous evolution. This `discontinuous' quantum walk employs perfect quantum state transfer between two nodes of specific subgraphs chosen to implement a universal gate set, thereby ensuring unitary evolution without requiring the introduction of an ancillary coin space. The run time is linear in the number of simulated qubits and gates. The scheme allows multiple runs of the algorithm to be executed almost simultaneously by starting walkers one timestep apart.Comment: 7 pages, revte