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A contemporary and innovative feature of post-mining land use (‘PMLU’) planning is the repurposing of sites such as mine-voids to alternative purposes such as pumped hydro, irrigated agriculture, renewable energy, or recreation and tourism. Repurposing can facilitate the transition of the region’s economy post-mining and contribute to rehabilitation for sites that cannot be returned to the pre-mining land use. A key issue inhibiting a third-party engaging in repurposing projects is the underlying tenure and the attached liability for residual and unforeseen risks. This article scopes out the tenure issue and considers whether introducing a new form of tenure in Western Australia could facilitate PMLU transitions and mitigate the frequent problem of sites languishing under care and maintenance.
Mammalian species richness is commonly highest at mid- to high elevations, but the accumulation of sediment that might bury and preserve skeletal remains generally occurs at lower elevations, leading to concerns that fossil assemblages are biased toward low-elevation taxa. Here, I use extant mammals as an analogue to test the basin-scale spatial overlap between species ranges and sediment sinks where burial and fossilization would be possible. Sediment sinks are estimated within five topographically complex regions in western North America by identifying areas with both a low slope and a high contributing area of runoff and are compared with point occurrences of mammals compiled from the Global Biodiversity Information Facility (GBIF). I find that, among the test areas, 82–96% of all species have occurrences that overlap with a sediment sink, despite common offsets in the elevations of maximum sink area and maximum species richness: summed across all test areas, 83% of species and 87% of total sediment sink area are found in the lowest 1000 m of the test areas. Although many other factors can act against the fossilization of terrestrial mammals, these results indicate that the spatial distribution of mammal species with respect to sediment sinks should not in itself impose a major bias at the basin scale.
The conventional $\textrm{e}^N$ laminar-to-turbulent transition-prediction method focuses on the relative growth rate, called the $N$ factor, and neglects receptivity. To improve predictions, Mack (1977) proposed the amplitude method to incorporate receptivity, nonlinear effects and broadband characteristics. Currently, the lack of accurate receptivity coefficients, estimates of initial disturbance amplitudes at the lower-branch neutral position, referred to as branch I (where the imaginary part of the spatial wavenumber is zero), hinders the application of the amplitude method. Although experimental- and numerical-receptivity analyses have been conducted previously, they rely on correlations or indirect approaches. For the purpose of direct evaluation, this study applies bi-orthogonal decomposition to direct numerical simulation (DNS) data of a hypersonic boundary layer over a blunt cone, extracting initial amplitudes of instability modes. The decomposition framework incorporates both boundary-layer and entropy-layer modes, enabling direct evaluation of receptivity coefficients at branch I. The decomposed modal amplitudes show reduced multimode interference and the receptivity coefficients have been computed to have fewer oscillations. With an overall greater magnitude, the receptivity coefficients suggest a possible earlier transition location than the previous numerical study by He & Zhong (2023 J. Spacecr. Rockets, vol. 60, no. 6, pp. 1927–1938). Additionally, a discrete entropy-layer mode is recovered, contributing to instability development alongside modes F and S. These findings support the use of bi-orthogonal decomposition as a practical tool for receptivity analysis and enhancement of the amplitude method in transition prediction.
The nonlinear growth of perturbations in hydrodynamic interfacial instabilities can be of particular importance in both scientific research (e.g. supernova explosion) and engineering applications (e.g. inertial confinement fusion). One of the most significant issues in these instabilities is the long-time nonlinear bubble evolution of a single-mode Rayleigh–Taylor instability (RTI), which remains as an unsolved and challenging problem since Taylor’s seminal work more than seven decades ago. Introduced in this paper is an analytical model for the long-time evolution of bubble velocity, curvature and vorticity, which is established by considering the vorticity accumulation around the bubble in a bilaterally rotational flow system under the classical planar potential-flow theory framework. The proposed theoretical model incorporates not only the classical linear, nonlinear and quasi-steady stages, but the late re-acceleration stage. Meanwhile, the new model can capture the phenomenon of secondary velocity saturation following the stage of bubble re-acceleration. The good agreement between the present model and numerical simulations for all density ratios and dimensions confirms that the accumulation in vorticity tends to break the early stage buoyancy-drag equilibrium mechanism and leads to the establishment of a new equilibrium in the late-stage RTI.
Sequential photographic records of glacier termini go back to the mid-20th century, revealing climate-driven retreat. More recently, time-lapse imagery has enabled detailed analysis of glacier dynamics, including calving. Here, we use long-term, high-frequency (15 min) time-lapse images from May–October 2016 to manually investigate calving activity at Hansbreen, a marine-terminating glacier in Hornsund Fjord, Svalbard. We explore the spatio-temporal variability in calving frequency and styles along the glacier terminus and its relationship to environmental drivers. Average calving frequency was found to be 30 events d−1, and peaking at 60 d−1. The calving activity aligns well with air and ocean temperature at a seasonal scales, while some peaks in calving correspond to increased modeled meltwater runoff and rainfall. These links are inconsistent and reflect high complexity. Calving at Hansbreen varies greatly in time and across five delineated terminus zones. In two of the zones, over 60% of waterline events occur during ebb tide; these segments also experience regular ice cave formation. However, further efforts are needed to explore the high-frequency evolution of terminus morphology and its link to calving. Our dataset can also be used to train automated algorithms for calving detection from time-lapse imagery.
Asymmetries and anisotropies are widespread in biological systems, including in the structure and dynamics of cilia and eukaryotic flagella. These microscopic, hair-like appendages exhibit asymmetric beating patterns that break time-reversal symmetry needed to facilitate fluid transport at the cellular level. The intrinsic anisotropies in ciliary structure can promote preferential beating directions, further influencing their dynamics. In this study, we employ numerical simulation and bifurcation analysis of a mathematical model of a filament driven by a follower force at its tip to explore how intrinsic curvature and direction-dependent bending stiffnesses impact filament dynamics. Our results show that while intrinsic curvature is indeed able to induce asymmetric beating patterns when filament motion is restricted to a plane, this beating is unstable to out-of-plane perturbations. Furthermore, we find that a three-dimensional whirling state seen for isotropic filament dynamics can be suppressed when sufficient asymmetry or anisotropy are introduced. Finally, for bending stiffness ratios as low as 2, we demonstrate that combining structural anisotropy with intrinsic curvature can stabilise asymmetric beating patterns, highlighting the crucial role of anisotropy in ciliary dynamics.
Luminescence dating and profiling are important analytical methods for providing chronological constraints and reconstructing depositional histories from sediment cores. However, sediment cores have often been exposed to ionising radiation sources during geophysical analyses, which potentially contaminates natural luminescence signals and may compromise the accuracy and reliability of luminescence analyses. Variable water content down-core is another potential issue for the rapid analysis of sediments, as water attenuates luminescence and may limit the comparability of samples. Here, we use a portable optically stimulated luminescence reader to test the influence of two common geophysical analyses—X-radiography and gamma-ray logging—on the luminescence properties of sediments in marine cores. We demonstrate that both techniques cause negligible changes to luminescence signals with doses <100 mGy. We test the effect of variable water content on luminescence and show that net signals are reduced by up to 70% at 30% moisture, relative to dry sediments. Accurate and reliable luminescence signals can be obtained from sediment cores despite prior exposure to ionising radiation from geophysical loggers or variable water content. However, the accuracy of luminescence measurements does require taking appropriate steps before analysis, like assessing the doses given by geophysical instruments at specific laboratories or drying samples.
This article addresses the transformative role of ethnoarchaeology in reshaping the study of pastoralism. Long marginalized by dominant scientific and political discourses, pastoralism is now increasingly seen as a sophisticated, adaptive livelihood strategy – especially in contexts of high environmental variability. Since pastoralism is predominantly practiced in drylands – arid and semiarid regions historically viewed as peripheral – its study has helped reframe these environments as dynamic landscapes of innovation and resilience. This reevaluation has been pushed, this article argues, also by the contributions of ethnoarchaeology. As a field that bridges past and present, it has enabled the generation of new concepts, the challenge of traditional archaeological frameworks and the integration of Indigenous knowledge systems.
The motionless conducting state of liquid-metal convection with an applied vertical magnetic field confined in a vessel with insulating sidewalls becomes linearly unstable to wall modes through a supercritical pitchfork bifurcation. Nevertheless, we show that the transition proceeds subcritically, with stable finite-amplitude solutions with different symmetries existing at parameter values beneath this linear stability threshold. Under increased thermal driving, the branch born from the linear instability becomes unstable and solutions are attracted to the most subcritical branch, which follows a quasiperiodic route to chaos. Thus, we show that the transition to turbulence is controlled by this subcritical branch and hence turbulent solutions have no connection to the initial linear instability. This is further quantified by observing that the subcritical equilibrium solution sets the spatial symmetry of the turbulent mean flow and thus organises large-scale structures in the turbulent regime.
The Salapunku archaeological site is located within the Historic Sanctuary – National Archaeological Park of Machu Picchu (HS-NAPM) in the Cusco area of Peru. Although Salapunku is related to the Inca settlements of the HS-NAPM, during archaeological excavations, we distinguished different moments of cultural occupation from the earliest human presence to complex pre-Hispanic societies such as the Inca and finally to the colonial period. Previous research on the site’s chronology was based on typological analyses of pottery and other artifacts found during archaeological research. This radiocarbon analysis, the first of its kind in this area, establishes a chronology of the cultural history of this significant settlement, considered the gateway to the Cordillera of Vilcabamba.
Internal waves in a two-layer fluid with rotation are considered within the framework of Helfrich’s $f$-plane extension of the Miyata–Maltseva–Choi–Camassa model. We develop simultaneous asymptotic expansions for the evolving mean fields and deviations from them to describe a large class of uni-directional waves via the Ostrovsky equation, which fully decouples from mean-field variations. The latter generate additive inertial oscillations in the shear and in the phase of both the interfacial displacement and shear. Unlike conventional derivations leading to the Ostrovsky equation, our formulation does not impose the zero-mean constraints on the initial conditions of any variable. Using the constructed solutions, we model the evolution of quasi-periodic initial conditions close to the cnoidal wave solutions of the Korteweg–de Vries (KdV) equation but with local defects, both with and without rotation. We show that rotation leads to the emergence of bursts of internal waves and shear currents, qualitatively similar to the wavepackets generated from solitons and modulated cnoidal waves in earlier studies, but emerging much faster. We also show that cnoidal waves with expansion defects discussed in this work are generalised travelling waves of the KdV equation: they satisfy all conservation laws of the KdV equation (appropriately understood), as well as the Weirstrass–Erdmann corner condition for broken extremals of the associated variational problem and a natural weak formulation. Being smoothed in numerical simulations, they behave, in the absence of rotation, as long-lived states with no visible evolution, while rotation leads to the emergence of strong bursts.
We study the stability of a steady Eckart streaming jet flowing in a closed cylindrical cavity. This configuration is a generic representation of industrial processes where driving flows in a cavity by means of acoustic forcing offers a contactless way of stirring or controlling flows. Successfully doing so, however, requires sufficient insight into the topology induced by the acoustic beam. This, in turn, raises the more fundamental question of whether the basic jet topology is stable and, when it is not, of the alternative states that end up being acoustically forced. To answer these questions, we consider a flow forced by an axisymmetric diffracting beam of attenuated sound waves emitted by a plane circular transducer at one cavity end. At the opposite end, the jet impingement drives recirculating structures spanning nearly the entire cavity radius. We rely on linear stability analysis (LSA) together with three-dimensional nonlinear simulations to identify the flow destabilisation mechanisms and to determine the bifurcation criticalities. We show that flow destabilisation is closely related to the impingement-driven recirculating structures, and that the ratio $C_R$ between the cavity and the maximum beam radii plays a key role on the flow stability. In total, we identified four mode types destabilising the flow. For $4 \leqslant C_R \leqslant 6$, a non-oscillatory perturbation rooted in the jet impingement triggers a supercritical bifurcation. For $C_R = 3$, the flow destabilises through a subcritical non-oscillatory bifurcation and we explain the topological change of the unstable perturbation by analysing its critical points. Further reducing $C_R$ increases the shear within the flow and gradually moves the instability origin to the shear layer between impingement-induced vortices: for $C_R = 2$, an unstable travelling wave grows out of a subcritical bifurcation, which becomes supercritical for $C_R=1$. For each geometry, the nonlinear three-dimensional (3-D) simulations confirm both the topology and the growth rate of the unstable perturbation returned by LSA. This study offers fundamental insight into the stability of acoustically driven flows in general, but also opens possible pathways to either induce turbulence acoustically or to avoid it in realistic configurations.
This book documents the mobilisation of law to retaliate against, intimidate, and even punish environmental defenders in Southeast Asia. It draws on case studies from Indonesia, Thailand, and the Philippines, which have taken measures to provide legal protection to environmental defenders by adopting anti-SLAPP provisions. Despite these provisions, attacks utilising legal means against environmental defenders have persisted. Environmental activists and local communities defending their livelihoods and the environment against the encroachment of extractive industries and state-backed development projects are turned into defendants before the courts. The book explains 1) the nature of legal attacks on environmental defenders in Southeast Asia, 2) the consequences of these attacks on environmental movements in those countries, and 3) the responses of environmental movements in navigating the existing politico-legal structures to resist these attacks and their strategies to strengthen the protection of environmental defenders in the region.
The family Kogiidae, comprising the pygmy sperm whale (Kogia breviceps) and the dwarf sperm whale (K. sima), represents some of the least-known cetaceans worldwide. Their small size, deep-diving behaviour, and elusive surface activity result in very few live sightings, particularly in the North Atlantic Ocean. Here, we report two significant observations from the Azores in July 2025: a group of six K. breviceps, the largest reported group size of this species, and a confirmed sighting of K. sima off Pico Island – representing only the sixth record for the archipelago. Photographic evidence and expert validation confirmed the identification of K. sima based on body proportions. We also review records of both species, including other live encounters and strandings, across the Macaronesian archipelagos (Azores, Madeira, Canary Islands, and Cape Verde). Together, our observations and synthesis document an exceptional group size for K. breviceps, emphasise the rarity of K. sima in the region, and highlight the value of whale-watching platforms and citizen science for monitoring elusive cetaceans.
Planamandibulus nevadensis n. gen n. sp. is a newly discovered exceptionally preserved Laurentian phosphatocopid crustacean described from the upper Windfall Formation (Furongian, Stage 10) in Nevada. Planamandibulus nevadensis has closest affinity with the Baltic and Avalonian taxon Cyclotron. Its occurrence in sedimentary facies associated with dysoxia on the Laurentian paleocontinent fills in a gap in the global distribution of phosphatocopid crustaceans, facilitating a paleoenvironmental synthesis of this Cambrian group. We assess 75 taxa from nine paleocontinental areas spanning Cambrian stages 3 to 10 (~521–486.9 Ma). Comparison of these data with paleoclimate model simulations suggests that phosphatocopid distribution is explained partly by biogeography and ocean temperature patterns. Dabashanella species (e.g., D. hemicyclica Huo et al., 1983) are found across the low paleolatitude (<35°) paleocontinents of East Gondwanan (Australia), South China, and the central Asian terranes, spanning marine shelf carbonates to deeper marine black shale lithofacies, but are absent from mid- and high-paleolatitude sites, suggesting a warmer water preference. A similar warm-water preference is inferred for endemic taxa (e.g., Ulopsis, Parashergoldopsis) of East Gondwana, and perhaps for the newly described Laurentian Planamandibulus. By contrast, the mid- to high-paleolatitude paleocontinents Baltica and Avalonia are characterized by Veldotron, Cyclotron, Bidimorpha, Waldoria, Vestrogothia, Falites, and Trapezilites species, which occur in deep-shelf, cooler-water settings, typically below storm wave base. Hesslandona species sensu lato occur in mid-depth (likely above storm-wave base) warm tropical marine waters but are more typically found in deeper shelf and cooler waters in mid to high paleolatitudes. Phosphatocopids are also associated with sedimentary deposits characteristic of low environmental oxygen concentrations; this is emphasized by a peak in occurrences in the Guzhangian (Miaolingian) and Paibian (Furongian) stages, around the interval of the Steptoean Positive Carbon Isotope Excursion (SPICE) and its associated expansion of anoxic water masses onto shallow marine shelves. Our data compilation and data–model comparison support the environmental preference of phosphatocopids for low-oxygen, but not anoxic, water masses, and the new occurrence of Planamandibulus is consistent with this pattern.