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We revisit the classical but as yet unresolved problem of predicting the breaking onset of 2D and 3D irrotational gravity water waves. Based on a fully nonlinear 3D boundary element model, our numerical simulations investigate geometric, kinematic and energetic differences between maximally tall non-breaking waves and marginally breaking waves in focusing wave groups. Our study focuses initially on unidirectional domains with flat bottom topography and conditions ranging from deep to intermediate depth (depth to wavelength ratio from 1 to 0.2). Maximally tall non-breaking (maximally recurrent) waves are clearly separated from marginally breaking waves by their normalised energy fluxes localised near the crest tip region. The initial breaking instability occurs within a very compact region centred on the wave crest. On the surface, this reduces to the local ratio of the energy flux velocity (here the fluid velocity) to the crest point velocity for the tallest wave in the evolving group. This provides a robust threshold parameter for breaking onset for 2D wave packets propagating in uniform water depths from deep to intermediate. Further targeted study of representative cases of the most severe laterally focused 3D wave packets in deep and intermediate depth water shows that the threshold remains robust. These numerical findings for 2D and 3D cases are closely supported by our companion observational results. Warning of imminent breaking onset is detectable up to a fifth of a carrier wave period prior to a breaking event.

Reports have questioned the dogma of exclusive maternal transmission of human mitochondrial DNA (mtDNA), including the recent report of an admixture of two mtDNA haplogroups in individuals from three multigeneration families. This was interpreted as being consistent with biparental transmission of mtDNA in an autosomal dominant–like mode. The authenticity and frequency of these findings are debated. We retrospectively analyzed individuals with two mtDNA haplogroups from 2017 to 2019 and selected four families for further study. We identified this phenomenon in 104/27,388 (approximately 1/263) unrelated individuals. Further study revealed (1) a male with two mitochondrial haplogroups transmits only one haplogroup to some of his offspring, consistent with nuclear transmission; (2) the heteroplasmy level of paternally transmitted variants is highest in blood, lower in buccal, and absent in muscle or urine of the same individual, indicating it is inversely correlated with mtDNA content; and (3) paternally transmitted apparent large-scale mtDNA deletions/duplications are not associated with a disease phenotype. These findings strongly suggest that the observed mitochondrial haplogroup of paternal origin resulted from coamplification of rare, concatenated nuclear mtDNA segments with genuine mtDNA during testing. Evaluation of additional specimen types can help clarify the clinical significance of the observed results.

This article focuses on the epic poem Thalaba the Destroyer by Robert Southey (1774–1843) and its musical refiguring as an 'orchestral poem' of 1899 by the British composer Granville Bantock (1868–1946). Just as the recent reappraisal of Southey's literary status has focused on concepts of orientalism and imperialism, this ideological framework can be used to explore Bantock and Southey's contrasting attitudes towards the East. The complexities highlighted in Southey's orientalism find a parallel in a range of stylistic layers identified in Bantock's musical refiguring of 'otherness' in Thalaba; these include musical tropes associated with Tchaikovsky, confirming Bantock as a significant figure in the reception of Russian music in Britain at the turn of the twentieth century. Bantock's approach to musical structure in Thalaba, contextualized via James Hepokoski's theory of sonata deformation, highlights his experimental approach to the relationship between musical text and paratext, suggesting that his status should be reassessed.

The evaluation of armor stone performance as a viable construction material is essential to increasing the longevity of maritime structures used to protect harbors, coastal areas and navigable waterways from damaging waves and other forces. The environmental parameters have led to the armor stones deteriorating faster than laboratory testing indicates. This paper provides an overview of the decomposition of the four rock types (limestone, granite, quartzite, and concrete) over the five field inspections. The meteorological variables were used to calculate the number of freeze-thaw events that occurred over the time period. The water wave height data were used to calculate stone deterioration from wave actions. The results from the field observations, together with the meteorological analysis, were used to help better parameterize the numerical model and assist in identifying problems in scalability from laboratory test samples to field samples.

Evaluating long-term performance and deterioration of armor stones are essential for maritime structures to protect harbors or navigable areas. Armor rocks are impacted by the natural elements such as seasonal weather, and repeated cycles of temperature (e.g., flowing water, wetting and drying, wave action, freeze and thaw, etc.). The rock's behavior in the field may vary greatly from the controlled laboratory test results. The design process for the determination of optimal armor stone sizes is complex. Numerous investigators have studied the development of relationships for the minimum stable weight of a rubble-mound armor unit for given wave conditions. The main objective of this study has been to evaluate major factors involved in armor stone durability. To consider the combined effects of environmental stresses on armor stone, several testing procedures have been developed to evaluate the performance of stone subjected to both freezing and thawing and wetting and drying. Long-term performance or deterioration of armor stones have been quantitatively monitored and characterized by the changes in dimensions measured. A degradation numerical model has been developed that relates the laboratory test results to the armor stone mass reduction at the project site. The paper describes the latest results and developed tools for the armor stone evaluations. New approaches are introduced that may be used to evaluate the quality and durability with reference to breakage and integrity.

We revisit the classical but as yet unresolved problem of predicting the breaking onset of 2D and 3D irrotational gravity water waves. This study focuses on domains with flat bottom topography and conditions ranging from deep to intermediate depth (depth to wavelength ratio from 1 to 0.2). Our calculations based on a fully nonlinear boundary element model investigated geometric, kinematic and energetic differences between maximally recurrent and marginally breaking waves in focusing wave groups. Maximally steep non-breaking (maximally recurrent) waves are clearly separated from marginally breaking waves by their normalised energy fluxes localized near the crest region. On the surface, this reduces to the local ratio of the energy flux velocity (here the fluid velocity) to the crest point velocity for the tallest wave in the evolving group. This provides a robust threshold parameter for breaking onset for 2D and 3D wave packets propagating in uniform water depths from deep to intermediate. Warning of imminent breaking onset was found to be detected up to a fifth of a carrier wave period prior to a breaking event.

The kinematic properties of unsteady highly non-linear 3D wave groups have been investigated using a numerical wave tank. Although carrier wave speeds based on zero-crossing analysis remain within +-7% of linear theory predictions, crests and troughs locally undertake a systematic cyclical leaning from forward to backward as the crests/troughs transition through their maximum amplitude. Consequently, both crests and troughs slow down by approximately 15% of the linear velocity, in sharp contrast to the predictions of finite amplitude Stokes steady wavetrain theory. Velocity profiles under the crest maximum have been investigated and surface values in excess of 1.8 times the equivalent Stokes velocity can be observed. Equipartitioning between depth-integrated kinetic and potential energy holds globally on the scale of the wave group. However, equipartitioning does not occur at crests and troughs (even for low amplitude Stokes waves), where the local ratio of potential to total energy varies systemically as a function of wave steepness about a mean value of 0.67.