431 research outputs found

    Probabilistic Landslide Tsunami Estimation in the Makassar Strait, Indonesia, Using Statistical Emulation

    Get PDF
    This paper presents a significant advancement in the understanding of tsunamigenic landslide hazard across the length of the Makassar Strait in Indonesia. We use statistical emulation across the length of the continental slope to conduct a probabilistic assessment of tsunami hazard on a regional scale, across 14 virtual coastal gauges. Focusing on the potential maximum wave amplitudes (distance between the wave crest and the still‐water level) from possible tsunamigenic landslide events, we generate predictions from Gaussian Process emulators fitted to input‐outputs from 50 training scenarios. We show that the most probable maximum wave amplitudes in the majority of gauges are between 1 and 5 m, with the maximum predicted amplitudes reaching values of up to 10 m on the eastern coast, and up to 50 m on the western coast. We also explore the potential use of Gaussian multivariate copulas to sample emulator prediction input values to create a more realistic distribution of volumes along the continental slope. The novel use of statistical emulation across a whole slope enables the probabilistic assessment of tsunami hazard due to landslides on a regional scale. This area is of key interest to Indonesia since the new capital will be established in the East Kalimantan region on the western side of the Makassar Strait

    Orbital Dimer Model for Spin-Glass State in Y2_2Mo2_2O7_7

    Full text link
    The formation of a spin glass usually requires both structural disorder and frustrated magnetic interactions. Consequently, the origin of spin-glass behaviour in Y2_2Mo2_2O7_7 −- in which magnetic Mo4+^{4+} ions occupy a frustrated pyrochlore lattice with minimal compositional disorder −- has been a longstanding question. Here, we use neutron and X-ray pair-distribution function (PDF) analysis to develop a disorder model that resolves apparent incompatibilities between previously-reported PDF, EXAFS and NMR studies and provides a new and physical mechanism for spin-glass formation. We show that Mo4+^{4+} ions displace according to a local "2-in/2-out" rule on each Mo4_4 tetrahedron, driven by orbital dimerisation of Jahn-Teller active Mo4+^{4+} ions. Long-range orbital order is prevented by the macroscopic degeneracy of dimer coverings permitted by the pyrochlore lattice. Cooperative O2−^{2-} displacements yield a distribution of Mo−-O−-Mo angles, which in turn introduces disorder into magnetic interactions. Our study demonstrates experimentally how frustration of atomic displacements can assume the role of compositional disorder in driving a spin-glass transition.Comment: 6 pages, 3 figure

    Is Environmental Enrichment Ready for Clinical Application in Human Post-stroke Rehabilitation?

    Get PDF
    Environmental enrichment (EE) has been widely used as a means to enhance brain plasticity mechanisms (e.g., increased dendritic branching, synaptogenesis, etc.) and improve behavioral function in both normal and brain-damaged animals. In spite of the demonstrated efficacy of EE for enhancing brain plasticity, it has largely remained a laboratory phenomenon with little translation to the clinical setting. Impediments to the implementation of enrichment as an intervention for human stroke rehabilitation and a lack of clinical translation can be attributed to a number of factors not limited to: (i) concerns that EE is actually the “normal state” for animals, whereas standard housing is a form of impoverishment; (ii) difficulty in standardizing EE conditions across clinical sites; (iii) the exact mechanisms underlying the beneficial actions of enrichment are largely correlative in nature; (iv) a lack of knowledge concerning what aspects of enrichment (e.g., exercise, socialization, cognitive stimulation) represent the critical or active ingredients for enhancing brain plasticity; and (v) the required “dose” of enrichment is unknown, since most laboratory studies employ continuous periods of enrichment, a condition that most clinicians view as impractical. In this review article, we summarize preclinical stroke recovery studies that have successfully utilized EE to promote functional recovery and highlight the potential underlying mechanisms. Subsequently, we discuss how EE is being applied in a clinical setting and address differences in preclinical and clinical EE work to date. It is argued that the best way forward is through the careful alignment of preclinical and clinical rehabilitation research. A combination of both approaches will allow research to fully address gaps in knowledge and facilitate the implementation of EE to the clinical setting

    Soil Disturbance by Invertebrates in a Semi-arid Eucalypt Woodland: Effects of Grazing Exclusion, Faunal Reintroductions, Landscape and Patch Characteristics

    Get PDF
    Soil disturbing invertebrates are common elements of arid and semi-arid landscapes. Disturbances such as burrows, nest entrances, emergence holes and mounds of ejecta soil have large, but often poorly understood, effects on ecosystem properties and processes as broad as pedogenesis, soil movement and water inïŹltration. We examined disturbances created by a range of invertebrates in a semi-arid eucalypt woodland in eastern Australia in relation to three levels of disturbance varying from areas currently grazed by domestic herbivores to those where domestic herbivores have been removed, with and without the reintroduction of locally-extinct omnivorous native mammals. Overall, the tunnels and ejecta soil from ant nests comprised 80% of all invertebrate disturbances across all sites and treatments. There were signiïŹcantly more invertebrate disturbances at sites where domestic herbivores had been excluded, more disturbances on dunes and in the swales than on plains, and more under shrubs than under trees. The cover of disturbances by invertebrates tended to increase with increasing cover of disturbance by native vertebrates, but only under exclosure where no locally-extinct native mammals had been reintroduced. Our results indicate that invertebrate-created disturbances are a common feature of semi-arid woodland soils, and that management activities, such as grazing and the reintroduction of locally-extinct vertebrates, will affect their density, potentially inïŹ‚uencing a range of ecosystem processes

    Soil Disturbance by Invertebrates in a Semi-arid Eucalypt Woodland: Effects of Grazing Exclusion, Faunal Reintroductions, Landscape and Patch Characteristics

    Get PDF
    . Soil disturbance by invertebrates in a semiarid eucalypt woodland: effects of grazing exclusion, faunal reintroductions, landscape and patch characteristics. Proceedings of the Linnean Society of New South Wales 134, A11-A18. Soil disturbing invertebrates are common elements of arid and semi-arid landscapes. Disturbances such as burrows, nest entrances, emergence holes and mounds of ejecta soil have large, but often poorly understood, effects on ecosystem properties and processes as broad as pedogenesis, soil movement and water infi ltration. We examined disturbances created by a range of invertebrates in a semi-arid eucalypt woodland in eastern Australia in relation to three levels of disturbance varying from areas currently grazed by domestic herbivores to those where domestic herbivores have been removed, with and without the reintroduction of locally-extinct omnivorous native mammals. Overall, the tunnels and ejecta soil from ant nests comprised 80% of all invertebrate disturbances across all sites and treatments. There were signifi cantly more invertebrate disturbances at sites where domestic herbivores had been excluded, more disturbances on dunes and in the swales than on plains, and more under shrubs than under trees. The cover of disturbances by invertebrates tended to increase with increasing cover of disturbance by native vertebrates, but only under exclosure where no locally-extinct native mammals had been reintroduced. Our results indicate that invertebrate-created disturbances are a common feature of semi-arid woodland soils, and that management activities, such as grazing and the reintroduction of locally-extinct vertebrates, will affect their density, potentially infl uencing a range of ecosystem processes

    Lions at the Gates: Trans-disciplinary Design of an Early Warning System to Improve Human-Lion Coexistence

    Get PDF
    Across Africa, lions (Panthera leo) are heavily persecuted in anthropogenic landscapes. Trans-disciplinary research and virtual boundaries (geofences) programmed into GPS-tracking transmitters offer new opportunities to improve coexistence. During a 24-month pilot study (2016–2018), we alerted communities about approaching lions, issuing 1,017 alerts to four villages and 19 cattle posts. Alerts reflected geofence breaches of nine lions (2,941 monitoring days) moving between Botswana's Okavango Delta and adjacent agro-pastoral communities. Daily alert system costs per lion were US18.54,or18.54, or 5,460.24 per GPS deployment (n = 13). Alert-responsive livestock owners mainly responded by night-kraaling of cattle (68.9%), significantly reducing their losses (by 124.61annually),whereaslossesofcontrolgroupandnon−responsivelivestockownersremainedhigh(124.61 annually), whereas losses of control group and non-responsive livestock owners remained high (317.93 annually). Community satisfaction with alerts (91.8%) was higher than for compensation of losses (24.3%). Study lions spent 26.3% of time monitored in geofenced community areas, but accounted for 31.0% of conflict. Manual alert distribution proved challenging, static geofences did not appropriately reflect human safety or the environment's strong seasonality that influenced cattle predation risk, and tracking units with on-board alert functions often failed or under-recorded geofence breaches by 27.9%. These insufficiencies prompted the design of a versatile and autonomous lion alert platform with automated, dynamic geofencing. We co-designed this prototype platform with community input, thereby incorporating user feedback. We outline a flexible approach that recognizes conflict complexity and user community heterogeneity. Here, we describe the evolution of an innovative Information and Communication Technologies-based (ICT) alert system that enables instant data processing and community participation through interactive interfaces on different devices. We highlight the importance of a trans-disciplinary co-design and development process focussing on community engagement while synthesizing expertise from ethnography, ecology, and socio-informatics. We discuss the bio-geographic, social, and technological variables that influence alert system efficacy and outline opportunities for wider application in promoting coexistence and conservation

    Relative efforts of countries to conserve world’s megafauna

    Get PDF
    Surprisingly little attention has been paid to variation among countries in contributions to conservation. As a first step, we developed a Megafauna Conservation Index (MCI) that assesses the spatial, ecological and financial contributions of 152 nations towards conservation of the world’s terrestrial megafauna. We chose megafauna because they are particularly valuable in economic, ecological and societal terms, and are challenging and expensive to conserve. We categorised these 152 countries as being above- or below-average performers based on whether their contribution to megafauna conservation was higher or lower than the global mean; ‘major’ performers or underperformers were those whose contribution exceeded 1 SD over or under the mean, respectively. Ninety percent of countries in North/Central America and 70% of countries in Africa were classified as major or above-average performers, while approximately one-quarter of countries in Asia (25%) and Europe (21%) were identified as major underperformers. We present our index to emphasize the need for measuring conservation performance, to help nations identify how best they could improve their efforts, and to present a starting point for the development of more robust and inclusive measures (noting how the IUCN Red List evolved over time). Our analysis points to three approaches that countries could adopt to improve their contribution to global megafauna conservation, depending on their circumstances: 1) upgrading or expanding their domestic protected area networks, with a particular emphasis on conserving large carnivore and herbivore habitat, 2) increase funding for conservation at home or abroad, or 3) ‘rewilding’ their landscapes. Once revised and perfected, we recommend publishing regular conservation rankings in the popular media to recognise major-performers, foster healthy pride and competition among nations, and identify ways for governments to improve their performance
    • 

    corecore