Assessment of the environmental impacts of ASR schemes.

This report describes the results of modelling studies undertaken to assess the impacts of ASR on the local environment. Understanding and quantifying these impacts, in relation to other existing or proposed schemes, will be vital in the development, and subsequent licensing of any ASR scheme. As each individual scheme has its own hydrogeological and environmental setting, as well as operational requirements, an all-encompassing model cannot be prescribed. Rather, a set of models, of increasing complexity, have been run for ‘typical’ scenarios to illustrate their use and limitations. They are designed to act as screening tools to assist practitioners, at all stages of an investigation, to decide on the suitability of a site and to identify what additional data are required in order to proceed to the next stage. The models are appended to the report so practitioners can apply them to their specific site, as appropriate

Deep-water antipatharians: Proxies of environmental change

Deep-water (307–697 m) antipatharian (black coral) specimens were collected from the southeastern continental slope of the United States and the north-central Gulf of Mexico. The sclerochronology of the specimens indicates that skeletal growth takes place by formation of concentric coeval layers. We used 210Pb to estimate radial growth rate of two specimens, and to establish that they were several centuries old. Bands were delaminated in KOH and analyzed for carbon and nitrogen stable isotopes. Carbon values ranged from _16.4‰ to _15.7‰; the oldest specimen displayed the largest range in values. Nitrogen values ranged from 7.7‰ to 8.6‰. Two specimens from the same location and depth had similar 15N signatures, indicating good reproducibility between specimens

The dynamics of floating bodies in a regular wave environment

Theoretical and numerical investigations have been carried out on the use of the Integral Equation Method of solution for the Potential Theory problem of the interaction between a floating body and a train of regular waves in a two-dimensional domain. In particular, a numerical study has been carried out of the indirect method of solution of the integral equation resulting from a distribution of Green's Function sources over a boundary coincident with the immersed surface of the body. It is demonstrated that a significant increase in solution efficiency, with no loss of precision, can be effected by improvements in the general numerical techniques of solution together with the use of a polynomial type distribution of elements over the source boundary. It is also demonstrated that significant improvements in solution accuracy for rectangular aspects can be achieved by a slight 'rounding' of the submerged edges of the mathematical model. An experimental investigation of the interaction between a train of regular waves and a substantially rectangular floating body includes measurements of the reflection and transmission characteristics, for both the fixed and floating mode of the body, together with measurements of the body motions. The primary objective of the experimental study is the validation of theoretically predicted interaction parameters derived from the above methods. The experimental program was designed both to determine the extent of validity of Potential Theory within regimes where diffraction effects predominate, and also to determine the conditions under which the use of Potential Theory alone becomes invalid due to the significant presence of non-linear effects. As a consequence of the results of this investigation, recommendations are made both with regard to the possible achievement of further improvements in solution efficiency and, more importantly, with regard to a general improvement of solution accuracy by the inclusion of the above-mentioned non-linear effects in the theoretical formulations

Identifying the mechanisms underpinning recognition of structured sequences of action

© 2012 The Experimental Psychology SocietyWe present three experiments to identify the specific information sources that skilled participants use to make recognition judgements when presented with dynamic, structured stimuli. A group of less skilled participants acted as controls. In all experiments, participants were presented with filmed stimuli containing structured action sequences. In a subsequent recognition phase, participants were presented with new and previously seen stimuli and were required to make judgements as to whether or not each sequence had been presented earlier (or were edited versions of earlier sequences). In Experiment 1, skilled participants demonstrated superior sensitivity in recognition when viewing dynamic clips compared with static images and clips where the frames were presented in a nonsequential, randomized manner, implicating the importance of motion information when identifying familiar or unfamiliar sequences. In Experiment 2, we presented normal and mirror-reversed sequences in order to distort access to absolute motion information. Skilled participants demonstrated superior recognition sensitivity, but no significant differences were observed across viewing conditions, leading to the suggestion that skilled participants are more likely to extract relative rather than absolute motion when making such judgements. In Experiment 3, we manipulated relative motion information by occluding several display features for the duration of each film sequence. A significant decrement in performance was reported when centrally located features were occluded compared to those located in more peripheral positions. Findings indicate that skilled participants are particularly sensitive to relative motion information when attempting to identify familiarity in dynamic, visual displays involving interaction between numerous features

Stocktaking the environmental coverage of a continental ecosystem observation network

Field-based sampling of terrestrial habitats at continental scales is required to build ecosystem observation networks. A key challenge for detecting change in ecosystem composition, structure, and function within these observatories is to obtain a representative sample of habitats. Representative sampling across a continent contributes to ecological validity when analyzing spatially distributed data. However, field resources are limited, and actual representativeness may differ markedly from theoretical expectations. Here, we report a post hoc evaluation of the coverage of environmental gradients as a surrogate for ecological representativeness by a continental-scale survey undertaken by the Australian Terrestrial Ecosystem Research Network (TERN). TERN’s surveillance program maintains a network of ecosystem observation plots initially established in the rangelands through a stratification method (clustering of bioregions by environment) and application of the Ausplots survey methodology. Subsequent site selection comprised gap-filling and opportunistic sampling. We confirmed that environmental coverage was a good surrogate for ecological representativeness. The cumulative sampling of environments and plant species composition over time were strongly correlated (based on mean multivariate dispersion; r = 0.93). We compared environmental sampling of Ausplots to 100,000 background points and a set of retrospective (virtual) sampling schemes: systematic grid, simple random, stratified random, and generalized randomtessellation stratified (GRTS). Differences were assessed according to sampling densities along environmental gradients, and multivariate dispersion. Ausplots outperformed systematic grid, simple random, and GRTS in coverage of environmental space (Tukey HSD of mean dispersion, P < 0.001). GRTS site selection obtained similar coverage to Ausplots when employing the same bioregional stratification. Stratification by climatic zones generated the highest environmental coverage (P < 0.001), although resulting sampling densities over-represented mesic coastal habitats. The Ausplots bioregional stratification implemented under practical constraints represented complex environments well, compared to statistically oriented or spatially even samples. Potential statistical power also depends on replication, unbiased site selection, and accuracy of field measurements relative to the magnitude of change. Consistent with previous studies, our stocktake analysis confirmed that environmental, rather than spatial, stratification is required to maximize ecological coverage across continental ecosystem observation networks, and the approach to establishing TERN Ausplots was robust. We recommend targeted gap-filling to complete sampling.Greg R. Guerin, Kristen J.Williams, Ben Sparrow, and Andrew J. Low

Volume Effects on the Glass Transition Dynamics

The role of jamming (steric constraints) and its relationship to the available volume is addressed by examining the effect that certain modifications of a glass-former have on the ratio of its isochoric and isobaric activation enthalpies. This ratio reflects the relative contribution of volume (density) and temperature (thermal energy) to the temperature-dependence of the relaxation times of liquids and polymers. We find that an increase in the available volume confers a stronger volume-dependence to the relaxation dynamics, a result at odds with free volume interpretations of the glass transition.Comment: 9 pages 5 figure