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Langmuir turbulence consists of Langmuir circulation (LC) generated at the surface of rivers, lakes, bays, and oceans by the interaction between the wind-driven shear and surface gravity waves. In homogeneous shallow water, LC can extend to the bottom of the water column and interact with the bottom boundary layer. Large-eddy simulation (LES) of LC in shallow water was performed with the finite volume method and various forms of subgrid-scale (SGS) model characterized by different near-wall treatments of the SGS eddy viscosity. The wave forcing relative to wind forcing in the LES was set following the field measurements of full-depth LC during the presence of LC engulfing a water column 15 m in depth in the coastal ocean, reported in the literature. It is found that the SGS model can greatly impact the structure of LC in the lower half of the water column. Results are evaluated in terms of (1) the Langmuir turbulence velocity statistics and (2) the lateral (crosswind) length scale and overall cell structure of LC. LES with an eddy viscosity with velocity scale in terms of S and Ω (where S is the norm of the strain rate tensor and Ω is the norm of the vorticity tensor) and a Van Driest wall damping function (referred to as the S-Omega model) is found to provide best agreement with pseudo-spectral LES in terms of the lateral length scale and overall cell structure of LC. Two other SGS models, namely the dynamic Smagorinsky model and the wall-adapting local-eddy viscosity model are found to provide less agreement with pseudo- spectral LES, for example, as they lead to less coherent bottom convergence of the cells and weaker associ ated upward transport of slow downwind moving fluid. Finally, LES with the S-Omega SGS model is also found to lead to good agreement with physical measurements of LC in the coastal ocean in terms of Langmuir turbulence decay during periods of surface heating 

The development of offshore wind technology has become a feasible solution to meet the increasing demands for clean and renewable energy. The United States has a total of 4250GW offshore wind energy potential; however, 65% of it is in deep water zones (Lopez et al., 2022) where wind turbines with fixed foundations typically are economically and technically unfeasible. In those situations, floating turbines supported by subsea anchors are a more competitive solution. Based on previous studies, ring anchors can be more material-efficient than piles and caissons because they require less material. Ring anchors also perform better than drag anchors due to their greater embedment depth. To further understand the behavior of ring anchors in saturated sand, a series of centrifuge load tests were performed at the University of California Davis Center for Geotechnical Modeling (CGM) at an acceleration of 70g. This test series investigated the effect of the anchor embedment depth and loading angle on the monotonic loading behavior. The ring anchor models were embedded in dense saturated sand, and then connected to an actuator using taut steel wire ropes. Sensors were used to measure the line tension, displacement, and inclination. The results indicate that the ring anchors mobilize greater capacities as their embedment depth is increased and when they are loaded at angles close to the horizontal direction, while vertical loading leads to the smallest capacity. The anchor displacement during the tests deviated slightly from the loading direction, showing a horizontal deviation at the earlier stages of the tests and a vertical one after the peak load. Furthermore, soil disturbance induced by the anchor installation was found to have a strong effect on the vertical capacity of the ring anchors. Overall, this study provides valuable information regarding the monotonic loading behavior of ring anchors which can aid in their future field deployment. 

Abstract Although cancer initiation and progression are generally associated with the accumulation of somatic mutations^1,2, substantial epigenomic alterations underlie many aspects of tumorigenesis and cancer susceptibility^3–6, suggesting that genetic mechanisms might not be the only drivers of malignant transformation⁷. However, whether purely non-genetic mechanisms are sufficient to initiate tumorigenesis irrespective of mutations has been unknown. Here, we show that a transient perturbation of transcriptional silencing mediated by Polycomb group proteins is sufficient to induce an irreversible switch to a cancer cell fate inDrosophila. This is linked to the irreversible derepression of genes that can drive tumorigenesis, including members of the JAK–STAT signalling pathway andzfh1, the fly homologue of theZEB1oncogene, whose aberrant activation is required for Polycomb perturbation-induced tumorigenesis. These data show that a reversible depletion of Polycomb proteins can induce cancer in the absence of driver mutations, suggesting that tumours can emerge through epigenetic dysregulation leading to inheritance of altered cell fates. 

Debris flow, landslides and material run-outs have significant environmental and economic consequences for numerous industries. High-quality experimental data with controlled boundary conditions can help validate and calibrate the predictive capabilities of mechanistic and semi-empirical numerical models. A novel centrifuge container to model dewatering and run-outs induced by a rapid loss of confinement is presented. The design features a pair of vertical doors opened in-flight to simulate failure of the containing structure. Illustrative centrifuge results investigating the run-out characteristics of a fully saturated, densely deposited class-F fly ash are presented. Modified soil moisture probes to monitor the distributions and time-varying fly-ash water content throughout the testing are explored. Furthermore, the successful use of depth-sensing cameras to reconstruct progressive deformations of the material front at various time scales is demonstrated. Combined water content, pore pressure and deformation measurements provide insight into the material behaviour during the run-out, revealing two time scales at which the deformations occur. However, discrepancies between water contents inferred from the dielectric measurements and electrical conductivities highlight the need for independent verification of the bulk material water content when using the modified probes. Overall, the potential of these innovative instrumentation techniques to complement traditional geotechnical instrumentation is shown. 

A multiline ring anchor (MRA) system has been developed as a cost-effective alternative for securing arrays of floating offshore wind turbines (FOWTs) to the seabed. Multiline attachments can improve the economically competitiveness of FOWTs by reducing the capital cost of the support system for the floating structures. FOWTs can be subjected to severe wind and wave conditions resulting in extreme loads to the anchor system. Thus, the reliable design of the anchor system requires proper determination of the extreme mooring line loads acting on the anchor needed to secure FOWTs to the seabed. Previous studies showed the MRA in soft clay has clear advantages over existing anchors under the extreme horizontal loading conditions imposed by catenary moorings; however, its performance relative to conventional anchors under extreme vertical loading imposed by taut mooring systems requires further investigation. This study presents predictions of extreme loads on floating structures secured by taut mooring systems and evaluates the potential for developing an economical anchor for resisting these extreme loads.