Characterising sand and gravel deposits using electrical resistivity tomography (ERT) : case histories from England and Wales

Electrical Resistivity Tomography (ERT) is a rapidly developing geophysical imaging technique that is now widely used to visualise subsurface geological structure, groundwater and lithological variations. It is being increasingly used in environmental and engineering site investigations, but despite its suitability and potential benefits, ERT has yet to be routinely applied by the minerals industry to sand and gravel deposit assessment and quarry planning. The principal advantages of ERT for this application are that it is a cost-effective non-invasive method, which can provide 2D or 3D spatial models of the subsurface throughout the full region of interest. This complements intrusive sampling methods, which typically provide information only at discrete locations. Provided that suitable resistivity contrasts are present, ERT has the potential to reveal mineral and overburden thickness and quality variations within the body of the deposit. Here we present a number of case studies from the UK illustrating the use of 2D and 3D ERT for sand and gravel deposit investigation in a variety of geological settings. We use these case studies to evaluate the performance of ERT, and to illustrate good practice in the application of ERT to deposit investigation. We propose an integrated approach to site investigation and quarry planning incorporating both conventional intrusive methods and ERT

Noisy commitments: The impact of information accuracy on efficiency

We report an experiment designed to test the influence of noisy commitments on efficiency in a simple bargaining game. We investigate two different levels of commitment reliability in a variant of the peasant-dictator game. Theoretical analysis suggests that the reliability of commitments in this game does not affect efficiency. We find that accurate commitments promote efficiency, as expected by game theory. However, noisy commitments are found to impair efficiency. We explain this effect by the differences between incentives off the equilibrium path under conditions of accurate commitments and noisy commitments. This difference changes the game structure and in the current game facilitates more random responses.Commitments, efficiency, experimental economics, information, trust

The emotional recall task : juxtaposing recall and recognition-based affect scales

Existing affect scales typically involve recognition of emotions from a predetermined emotion checklist. However, a recognition-based checklist may fail to capture sufficient breadth and specificity of an individual’s recalled emotional experiences and may therefore miss emotions that frequently come to mind. More generally, how do recalled emotions differ from recognized emotions? To address these issues, we present and evaluate an affect scale based on recalled emotions. Participants are asked to produce 10 words that best described their emotions over the past month and then to rate each emotion for how often it was experienced. We show that average weighted valence of the words produced in this task, the Emotional Recall Task (ERT), is strongly correlated with scales related to general affect, such as the PANAS, Ryff’s Scales of Psychological Well-being, the Satisfaction with Life Scale, Depression Anxiety and Stress Scales, and a few other related scales. We further show that the Emotional Recall Task captures a breadth and specificity of emotions not available in other scales but that are nonetheless commonly reported as experienced emotions. We test a general version of the ERT (the ERT general) that is language neutral and can be used across cultures. Finally, we show that the ERT is valid in a test-retest paradigm. In sum, the ERT measures affect based on emotion terms relevant to an individual’s idiosyncratic experience. It is consistent with recognition-based scales, but also offers a new direction towards enriching our understanding of individual differences in recalled and recognized emotions

Monitoring hydraulic processes with automated time-lapse electrical resistivity tomography (ALERT)

Hydraulic processes in porous media can be monitored in a minimally invasive fashion by time-lapse electrical resistivity tomography (ERT). The permanent installation of specifically designed ERT instrumentation, telemetry and information technology (IT) infrastructure enables automation of data collection, transfer, processing, management and interpretation. Such an approach gives rise to a dramatic increase in temporal resolution, thus providing new insight into rapidly occurring subsurface processes. In this paper, we discuss a practical implementation of automated time-lapse ERT. We present the results of a recent study in which we used controlled hydraulic experiments in two test cells at reduced field scale to explore the limiting conditions for process monitoring with cross-borehole ERT measurements. The first experiment used three adjacent boreholes to monitor rapidly rising and falling water levels. For the second experiment we injected a saline tracer into a homogeneous flow field in freshwater-saturated sand; the dynamics of the plume were then monitored with 2D measurements across a 9-borehole fence and 3D measurements across a 3x3 grid of boreholes. We investigated different strategies for practical data acquisition and show that simple re-ordering of ERT measurement schemes can help harmonise data collection with the nature of the monitored process. The methodology of automated time-lapse ERT was found to perform well in different monitoring scenarios (2D/3D plus time) at time scales associated with realistic subsurface processes. The limiting factor is the finite amount of time needed for the acquisition of sufficiently comprehensive datasets. We found that, given the complexity of our monitoring scenarios, typical frame rates of at least 1.5–3 images per hour were possible without compromising image quality

No Difference in Health Related Quality of Life Between Therapeutic Options for Type 1 Gaucher Disease

Type 1 Gaucher disease (GD) is the most common lysosomal storage disorder. Previously, treatment for GD was limited to intravenous enzyme replacement therapy (ERT). ERT reduces symptoms and increases health­related quality of life (HRQoL) in people with this condition. In 2014, oral substrate reduction therapy (SRT) was approved for type 1 GD treatment. Although both therapies alleviate disease symptoms, effects of SRT on HRQoL and preferences for therapy are not well established. Electronic surveys were administered to adults with type 1 GD. HRQoL was scored with the Short Form­36 Version 2 ® Health Survey and descriptive statistics were used to evaluate additional survey items. No differences in physical HRQoL (p = 0.756) or mental HRQoL (p = 0.650) were observed between SRT and ERT users. SRT users most often perceived their health to be similar to when they used ERT. Additionally, SRT users expressed convenience and non­invasiveness as reasons for choosing SRT, while many ERT users cited potential side effects and satisfaction with ERT as reasons for declining SRT. There appears to be no difference in HRQoL between ERT and SRT users and no perceived change in HRQoL for SRT users that previously used ERT. Participant responses illustrate that one particular treatment may not be ideal for all patients with type 1 GD depending on perceived convenience, invasiveness, or side effects. This evidence suggests that individuals with type 1 GD be adequately counseled about the risks and benefits of both therapy options now that SRT is clinically available