Application of Single-Station Sigma and Site-Response Characterization in a Probabilistic Seismic-Hazard Analysis for a New Nuclear Site

Aleatory variability in ground-motion prediction, represented by the standard deviation (sigma) of a ground-motion prediction equation, exerts a very strong influence on the results of probabilistic seismic-hazard analysis (PSHA). This is especially so at the low annual exceedance frequencies considered for nuclear facilities; in these cases, even small reductions in sigma can have a marked effect on the hazard estimates. Proper separation and quantification of aleatory variability and epistemic uncertainty can lead to defensible reductions in sigma. One such approach is the single-station sigma concept, which removes that part of sigma corresponding to repeatable site-specific effects. However, the site-to-site component must then be constrained by site-specific measurements or else modeled as epistemic uncertainty and incorporated into the modeling of site effects. The practical application of the single-station sigma concept, including the characterization of the dynamic properties of the site and the incorporation of site-response effects into the hazard calculations, is illustrated for a PSHA conducted at a rock site under consideration for the potential construction of a nuclear power plant.Civil, Architectural, and Environmental Engineerin

Comment on “The maximum possible and maximum expected earthquake magnitude for production-induced earthquakes at the gas field in Groningen, The Netherlands” by Gert Zöller and Matthias Holschneider

Zöller and Holschneider (2016) propose estimates of the maximum magnitude of induced earthquakes resulting from gas production in the Groningen field in The Netherlands by applying the approach of Zöller and Holschneider (2014) to the earthquake catalog for the Groningen field. We wish neither to make any comment on the analytical approach that the authors propose, nor to comment on their results in this particular application. We do feel obliged to clarify for readers the context of the study by Zöller and Holschneider (2016) in relation to the March 2016 workshop to which they refer. In particular, the sentence in their Introduction stating that “this short note provides the results of those authors” (p. 2917) could be interpreted as implying that their paper presents the results from the workshop. The paper by Zöller and Holschneider (2016) summarizes one of the many inputs that contributed to the workshop, but not the final outcome of the workshop

An improved framework for discriminating seismicity induced by industrial activities from natural earthquakes

Heightened concerns regarding induced seismicity necessitate robust methods to assess whether detected earthquakes near industrial sites are natural or induced by the industrial activity. These assessments are required rapidly, which often precludes detailed modeling of fluid pressures and the geomechanical response of the reservoir and nearby faults. Simple question‐based assessment schemes in current use are a useful tool but suffer from several shortcomings: they do not specifically address questions regarding whether available evidence supports the case for natural seismicity; they give all questions equal weighting regardless of the relative influence of different factors; they are not formulated to account for ambiguous or uncertain evidence; and the final outcomes can be difficult to interpret. We propose a new framework that addresses these shortcomings by assigning numerical scores to each question, with positive values for answers that support induced seismicity and negative values for responses favoring natural seismicity. The score values available for each question reflect the relative importance of the different questions, and for each question the absolute value of the score is modulated according to the degree of uncertainty. The final outcome is a score, the induced assessment ratio, either positive or negative (or zero), that reflects whether events were induced or natural. A second score, the evidence strength ratio, is assigned that characterizes the strength of the available evidence, expressed as the ratio of the maximum score possible with the available evidence relative to the maximum score that could be obtained if all desired data were available at a site. We demonstrate this approach by application to two case studies in the United Kingdom, one widely regarded as a case of induced seismicity, and the other more likely to be a series of tectonic earthquakes

Obstructed Left Retrocaval Ureter in a Dog

Retrocaval ureters form due to a congenital malformation of the caudal vena cava. This anomaly has been reported in cats and is usually incidental. Retrocaval ureters are rare in dogs, but have been associated with ureteral obstruction. When presented with a dog with hydroureter and hydronephrosis, an obstructed retrocaval ureter should be considered as a rare differential. This case report describes a left retrocaval ureter causing ureterohydronephrosis diagnosed by CT

Crystal structure and substrate specificity of the thermophilic serine:pyruvate aminotransferase from Sulfolobus solfataricus.

Journal ArticleResearch Support, Non-U.S. Gov'tThe three-dimensional structure of the Sulfolobus solfataricus serine:pyruvate aminotransferase has been determined to 1.8 Å resolution. The structure of the protein is a homodimer that adopts the type I fold of pyridoxal 5'-phosphate (PLP)-dependent aminotransferases. The structure revealed the PLP cofactor covalently bound in the active site to the active-site lysine in the internal aldimine form. The structure of the S. solfataricus enzyme was also determined with an amino form of the cofactor pyridoxamine 5'-phosphate bound in the active site and in complex with gabaculine, an aminotransferase inhibitor. These structures showed the changes in the enzyme active site during the course of the catalytic reaction. A comparison of the structure of the S. solfataricus enzyme with that of the closely related alanine:glyoxylate aminotransferase has identified structural features that are proposed to be responsible for the differences in substrate specificity between the two enzymes. These results have been complemented by biochemical studies of the substrate specificity and thermostability of the S. solfataricus enzyme.University of ExeterBBSRCEPSRCWellcome Trus

Sex Differences on Elementary Cognitive Tasks Despite No Differences on the Wonderlic Personnel Test

Whether males and females differ in general mental ability (GMA) remains an open question. Complicating the issue is that standardized IQ tests are constructed to minimize sex differences. We propose a potential solution whereby GMA is measured via performance on elementary cognitive tasks (ECTs). ECTs assess basic information-processing ability, yet correlate moderately highly with GMA. Toward this end, we had male (n = 218) and female (n = 226) undergraduates complete the Wonderlic Personnel Test (WPT), and two ECTs: inspection time (IT) and reaction time (RT). The sex difference on the WPT was non-significant (d = .17), but small differences favoring males existed for IT (d = .34), RT (d = .26), the standard deviation of RT (d = .30), and an ECT factor score (d = .38). Unlike standardized IQ tests, ECTs may be a viable research tool to help clarify and illuminate the nature of sex differences on GMA

Nonverbal Emotion Recognition and Performance: Differences Matter Differently

PURPOSE: This paper aims to explore and test the relationship between emotion recognition skill and assessment center performance after controlling for both general mental ability (GMA) and conscientiousness. It also seeks to test whether participant sex or race moderated these relationships. DESIGN/METHODOLOGY/APPROACH: Using independent observers as raters, the paper tested 528 business students participating in a managerial assessment center, while they performed four distinct activities of: an in-basket task; a team meeting for an executive hiring decision; a team meeting to discuss customer service initiatives; and an individual speech.FINDINGS: Emotion recognition predicted assessment center performance uniquely over both GMA and conscientiousness, but results varied by race. Females were better at emotion recognition overall, but sex neither was related to assessment center performance nor moderated the relationship between it and emotion recognition. The paper also found that GMA moderated the emotion recognition/assessment performance link, as the former was important to performance only for people with low levels of GMA. PRACTICAL IMPLICATIONS: The results seem to contradict those who argue that E-IQ is an unqualified predictor of performance. Emotional recognition is not uniformly valuable; instead, it appears to benefit some groups more than others. ORIGINALITY/VALUE: The paper clarifies the emotional intelligence literature by providing further support for the predictive validity of emotion recognition in performance contexts, and by separating out how emotional recognition benefits certain population groups more

Green, yellow, red, or out of the blue? An assessment of Traffic Light Schemes to mitigate the impact of hydraulic fracturing-induced seismicity

Mitigating hydraulic fracturing-induced seismicity (HF-IS) poses a challenge for shale gas companies and regulators alike. The use of Traffic Light Schemes (TLSs) is the most common way by which the hazards associated with HF-IS are mitigated. In this study, we discuss the implicit risk mitigation objectives of TLSs and explain the advantages of magnitude as the fundamental parameter to characterise induced seismic hazard. We go on to investigate some of the key assumptions on which TLSs are based, namely that magnitudes evolve relatively gradually from green to yellow to red thresholds (as opposed to larger events occurring “out-of-the-blue”), and that trailing event magnitudes do not increase substantially after injection stops. We compile HF-IS datasets from around the world, including the USA, Canada, the UK, and China, and track the temporal evolution of magnitudes in order to evaluate the extent to which magnitude jumps (i.e. sharp increases in magnitude from preceding events within a sequence) and trailing events occur. We find in the majority of cases magnitude jumps are less than 2 units. One quarter of cases experienced a post-injection magnitude increase, with the largest being 1.6. Trailing event increases generally occurred soon after injection, with most cases showing no increase in magnitude more than a few days after then end of injection. Hence, the effective operation of TLSs may require red-light thresholds to be set as much as two magnitude units below the threshold that the scheme is intended to avoid