Regional-scale controls on rockfall occurrence

Rockfalls exert a first-order control on the rate of rock wall retreat on mountain slopes and on coastal rock cliffs. Their occurrence is conditioned by a combination of intrinsic (resisting) and extrinsic (driving) processes, yet determining the exact effects of these processes on rockfall activity and the resulting cliff erosion remains difficult. Although rockfall activity has been monitored extensively in a variety of settings, high-resolution observations of rockfall occurrence on a regional scale are scarce. This is partly owing to difficulties in adequately quantifying the full range of possible rockfall volumes with sufficient accuracy and completeness, and at a scale that exceeds the influence of localised controls on rockfalls. This lack of insight restricts our ability to abstract patterns, to identify long-term changes in behaviour, and to assess how rock slopes respond to changes in both structural and environmental conditions, without resorting to a space for-time substitution. This thesis develops a workflow, from novel data collection to analysis, which is tailored to monitoring rockfall activity and the resulting cliff retreat continuously (in space), in 3D, and over large spatial scales $(> 10^4 m)$. The approach is tested by analysing rockfall activity and the resulting erosion recorded along 20.5 km of near-vertical coastal cliffs, in what is considered as the first multi-temporal detection of rockfalls at a regional-scale and in full 3D. The resulting data are then used to derive a quantitative appraisal of along-coast variations in the geometric properties of exposed discontinuity surfaces, to assess the extent to which these drive patterns in the size and shape of the rockfalls observed. High-resolution field monitoring is then undertaken along a subsection of the coastline $(> 10^2 m)$, where cliff lithology and structure are approximately uniform, in order to quantify spatial variations in wave loading characteristics and to relate these to local morphological conditions, which can act as a proxy for wave loading characteristics. The resulting rockfall inventory is analysed to identify the characteristics of rock slope change that only become apparent when assessed at this scale, placing bounds on data previously collected more locally $(< 10^2 m)$. The data show that spatial consistencies in the distribution of rockfall shape and volume through time approximately follow the geological setting of the coastline, but that variations in the strength of these consistencies are likely to be conditioned by differences in local processes and morphological controls between sites. These results are used to examine the relationships between key metrics of erosion, structural, and morphological controls, which ultimately permits the identification of areas where patterns of erosion are dominated by either intrinsic or extrinsic processes, or a mixture of both. Uniquely, the methodologies and data presented here mark a step-change in our ability to understand the competing effects of different processes in determining the magnitude and frequency of rockfall activity, and the resulting cliff erosion. The findings of this research hold considerable implications for our understanding of rockfalls, and for monitoring, modelling, and managing actively failing rock slopes

Dynamic analysis of long run-out rock avalanches: A view from the Vaigat Strait, West Greenland

Risk assessments of the threat posed by rock avalanches conventionally rely upon numerical modelling of potential run-out. Such models are contingent upon a thorough understanding of the flow dynamics inferred from deposits left by previous events. Few records exist of multiple rock avalanches with boundary conditions sufficiently consistent to develop a set of more generalised rules for behaviour. This thesis uses a numerical modelling approach to investigate the emplacement dynamics of 20 adjacent events in Vaigat, West Greenland, which are sourced from a stretch of coastal mountains of relatively uniform geology and structure. Rheological calibration of the numerical flow code VolcFlow was performed using a well constrained event at Paatuut (AD 2000). The best-fit simulation assumes a constant retarding stress with a collisional stress coefficient and simulates run-out to within ±0.3% of that observed. Despite being widely used to simulate rock avalanche propagation, other models, that assume either a Coulomb frictional or a Voellmy rheology, failed to reproduce the observed event characteristics and deposit distribution at Paatuut. This calibration was then applied to 19 other events, simulating rock avalanche motion across 3D terrain of varying levels of complexity. The findings illustrate the utility and sensitivity of modelling a single rock avalanche satisfactorily as a function of rheology, alongside the validity of applying the same parameters elsewhere, even within similar boundary conditions. VolcFlow can plausibly account for the observed morphology of a series of deposits emplaced by events of different types, although its performance is sensitive to a range of topographic and geometric factors. These exercises show encouraging results in the model’s ability to simulate a series of events using a single set of parameters obtained by back analysis of the Paatuut event alone, suggesting that first-order run-out prediction is possible

Visualizing India

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The Cost of Biotechnology Regulation in the Philippines

This paper identifies direct costs and opportunity costs of bio-safety regulation for four transgenic products in the Philippines: Bt eggplant, Bt rice, ringspot-virus resistant papaya, and virus resistant tomatoes. It finds that direct regulatory costs while significant, are generally smaller than the research costs for technology development. However, both research and regulatory costs are overshadowed by even a relatively brief delay in product release, which may occur due to unexpected regulatory delays.Food Consumption/Nutrition/Food Safety, Research and Development/Tech Change/Emerging Technologies,

Differential Diagnosis of Auditory Processing Disorder in Children: A Literature Review

Although there is no consensus on the definition of auditory processing disorder (APD), it is typically characterized by listening difficulties resulting from deficits in auditory perceptual processing of sounds in the central auditory nervous system. APD often co-occurs with other disabilities such as ADHD, dyslexia, and specific language impairment. Presenting symptoms can be very similar to these other disorder, complicating diagnosis. Due to the overlap of symptoms between APD and various other deficits, there are concerns that professionals in different fields are providing children with different labels for the same group of symptoms. Therefore, the aim of this literature review is to discuss the challenges in identifying APD and distinguishing it from other developmental disorders, especially in children. As part of the recommended clinical protocol in audiology, several test batteries are commonly used to diagnose APD through a combination of clinical observation, behavioral assessments with and without speech stimuli, electrophysiological assessments of brain activity in response to sound stimulation, and speech-language assessments. Although there is evidence supporting comorbidity between APD and other disorders, current test batteries alone do not have the specificity to distinguish APD from some other types of developmental delay. There is a need for the development of improved assessment techniques that are both sensitive to the presence of APD and at the same time do not result in false positive diagnoses of APD in children with other disorders. In the meantime, a multidisciplinary approach is emphasized for the assessment and intervention of APD in an attempt to reduce the risk of erroneous diagnosis of APD in children with other developmental disabilities

Bipolar disorder in pregnancy

This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of bipolar disorder in pregnant women

Liability for Public Deception: Linking Fossil Fuel Disinformation to Climate Damages

Over two dozen U.S. states and municipalities have filed lawsuits against fossil fuel companies, seeking abatement orders and compensation for climate damages based on theories such as public nuisance, negligence, and failure to warn, and alleging these companies knew about the dangers of their products, intentionally concealed those dangers, created doubt about climate science, and undermined public support for climate action. This Article examines how tort plaintiffs can establish a causal nexus between public deception and damages, drawing from past litigation, particularly claims filed against manufacturers for misleading the public about the risks of tobacco, lead paint, and opioids. A key finding is that courts may infer public reliance on false and misleading statements using multiple lines of evidence, including information about the scope and magnitude of the deceptive communications, defendants’ internal assessments of the efficacy of their disinformation campaigns, acknowledgements of intended reliance made by defendants, expert testimony on the effects of disinformation, public polling data, and more. The Article concludes with a discussion of these potential strategies and evidentiary sources