Contribution of gravity gliding in salt-bearing rift basins – a new experimental setup for simulating salt tectonics under the influence of sub-salt extension and tilting

Basin-scale salt flow and the evolution of salt structures in rift basins is mainly driven by sub- and supra-salt faulting and sedimentary loading. Crustal extension is often accompanied and followed by thermal subsidence leading to tilting of the graben flanks, which might induce an additional basinward-directed driver for salt tectonics. We designed a new experimental analogue apparatus capable of integrating the processes of sub-salt graben extension and tilting of the flanks, such that the overlapping effects on the deformation of a viscous substratum and the brittle overburden can be simulated. The presented experimental study was performed to demonstrate the main functionality of the experimental procedure and setup, demonstrating the main differences in structural evolution between conditions of pure extension, pure tilting, and extension combined with tilting. Digital image correlation of top-view stereoscopic images was applied to reveal the 3D displacement and strain patterns. The results of these experiments suggest that in salt basins affected by sub-salt extension and flank inclination, the salt flow and downward movement of overburden affects the entire flanks of the basin. Supra-salt extension occurring close to the graben centre is overprinted by the downward movement; i.e. the amount of extension is reduced or extensional faults zones are shortened. At the basin margins, thin-skinned extensional faults developed as a result of gravity gliding. A comparison with natural examples reveals that such fault zones can also be observed at the margins of many salt-bearing rift basins indicating that gravity gliding played a role in these basins.

Molecular Biomarkers of Electroconvulsive Therapy Effects and Clinical Response: Understanding the Present to Shape the Future

Electroconvulsive therapy (ECT) represents an effective intervention for treatment-resistant depression (TRD). One priority of this research field is the clarification of ECT response mechanisms and the identification of biomarkers predicting its outcomes. We propose an overview of the molecular studies on ECT, concerning its course and outcome prediction, including also animal studies on electroconvulsive seizures (ECS), an experimental analogue of ECT. Most of these investigations underlie biological systems related to major depressive disorder (MDD), such as the neurotrophic and inflammatory/immune ones, indicating effects of ECT on these processes. Studies about neurotrophins, like the brain-derived neurotrophic factor (BDNF) and the vascular endothelial growth factor (VEGF), have shown evidence concerning ECT neurotrophic effects. The inflammatory/immune system has also been studied, suggesting an acute stress reaction following an ECT session. However, at the end of the treatment, ECT produces a reduction in inflammatory-associated biomarkers such as cortisol, TNF-alpha and interleukin 6. Other biological systems, including the monoaminergic and the endocrine, have been sparsely investigated. Despite some promising results, limitations exist. Most of the studies are concentrated on one or few markers and many studies are relatively old, with small sample sizes and methodological biases. Expression studies on gene transcripts and microRNAs are rare and genetic studies are sparse. To date, no conclusive evidence regarding ECT molecular markers has been reached; however, the future may be just around the corner.

An Experimental Analogue Evaluation of Asian and Asian Americans’ Immediate Reactions to Therapist Microaggressions

Microaggressions are subtle, everyday exchanges that convey discriminatory messages. In psychotherapy, client reports of microaggressions are negatively associated with important therapeutic processes and outcomes. However, many studies are retrospective and correlational, and cannot establish the causal impact of specific therapist statements. In this study, Asian and Asian American participants recruited from Amazon Mechanical Turk ( N = 66) watched a brief animated counseling vignette, and were randomly assigned to four types of therapist responses to the client (control, subtle, moderate, and overt microaggressions). We assessed emotional reactions, perceptions of the session, and offensiveness of therapist statements. In general, moderate and overt microaggressions were rated much more negatively (Cohen’s d’s > 1.0) than subtle microaggressions or control statements (which were not significantly different from each other on any measure). We discuss implications for research, practice, and training.

Beyond the fold: experimentally traversing limit points in nonlinear structures

Recent years have seen a paradigm shift regarding the role of nonlinearities and elastic instabilities in engineering science and applied physics. Traditionally viewed as unwanted aberrations, when controlled to be reversible and well behaved, nonlinearity can enable novel functionalities, such as shape adaptation and energy harvesting. The analysis and design of novel structures that exploit nonlinearities and instabilities have, in part, been facilitated by advances in numerical continuation techniques. An experimental analogue of numerical continuation, on the other hand, has remained elusive. Traditional quasi-static experimental methods control the displacement or force at one or more load-introduction points over the test specimen. This approach fails at limit points in the control parameter, as the immediate equilibrium beyond limit points is statically unstable, causing the structure to snap to a different equilibrium. Here, we propose a quasi-static experimental path-following method that can continue along stable and unstable equilibria, and traverse limit points. In addition to controlling the displacement at the main load-introduction point, the technique relies on overall shape control of the structure using additional actuators and sensors. The proposed experimental method enables extended testing of the emerging class of structures that exploit nonlinearities and instabilities for novel functionality.

North American grooved-axe replication: A taphonomic experiment in central Connecticut

Taphonomic experiments in lithic technology have been used to understand many facets of the archaeological record including site-formation processes, artifact displacement, and wear damage. The North American grooved-axe - an artifact type of which little technological attention has been given in the literature - is examined as a case study for a taphonomic experiment conducted in Central Connecticut. The use of an actualistic taphonomic experiment is used to generate an analogous experimental signature for archaeological grooved-axe manufacturing areas in North America. More specifically, the taphonomic experiment is used here to see if the isolated technological stage of impaction is archaeologically visible before short-term formation processes affect the manufacturing area in question. Impaction is a ground stone tool manufacturing technique that is otherwise known as pecking or hammer-dressing. Hypothesized archaeological traces of impaction include the recovery of flakes with macroscopic impaction wear and a lens of impaction slurry that is both visibly and texturally distinct. In addition to generating an experimental analogue for grooved-axe impaction, the replicative dimension of the taphonomic experiment is used to informally assess the plausibility of certain technological decisions in axe manufacture. Here, the use of quartzite impaction tools and expedient anvils in the production of North American grooved-axes are scrutinized.