1,634 research outputs found

    Seismic resilience assessment of Small Modular Reactors by a Three-loop Monte Carlo Simulation

    Get PDF
    We develop a three-loop Monte Carlo Simulation (MCS) framework for the seismic resilience assessment of Small Modular Reactors (SMRs), embedding Probabilistic Seismic Hazard Analysis (PSHA), seismic fragility evaluation and multiple SMR units accident sequence analysis. A set of metrics are computed to capture different aspects of SMR resilience to earthquakes, specifically the ability to withstand seismic disruption, mitigate consequences and restore normal operation. The MCS framework allows accounting for the aleatory and epistemic uncertainties of the PSHA and fragility parameters. An application is given with regards to an advanced Nuclear Power Plant (aNPP) consisting of four reactor units of NuScale SMR design. A comparison is made to a conventional NPP (cNPP), i.e., a typical large reactor of equivalent generation capacity. Both plants are fictitiously located on the Garigliano nuclear site (southern Italy). The results show that resilient features of SMRs overcome cNPPs in terms of post-accident scenario mitigation and restoration capabilities

    A performance comparison of the contiguous allocation strategies in 3D mesh connected multicomputers

    Get PDF
    The performance of contiguous allocation strategies can be significantly affected by the distribution of job execution times. In this paper, the performance of the existing contiguous allocation strategies for 3D mesh multicomputers is re-visited in the context of heavy-tailed distributions (e.g., a Bounded Pareto distribution). The strategies are evaluated and compared using simulation experiments for both First-Come-First-Served (FCFS) and Shortest-Service-Demand (SSD) scheduling strategies under a variety of system loads and system sizes. The results show that the performance of the allocation strategies degrades considerably when job execution times follow a heavy-tailed distribution. Moreover, SSD copes much better than FCFS scheduling strategy in the presence of heavy-tailed job execution times. The results also show that the strategies that depend on a list of allocated sub-meshes for both allocation and deallocation have lower allocation overhead and deliver good system performance in terms of average turnaround time and mean system utilization

    Hide-and-seek in a highly human-dominated landscape: insights into movement patterns and selection of resting sites of rehabilitated wolves (Canis lupus) in Northern Italy

    Get PDF
    Assessing the behavioural responses of floating wolves to human presence is crucial for investigating the chance of wolf populations expanding into urbanised landscapes. We studied the movement ecology of three rehabilitated wolves in a highly human-dominated landscape (Po Plain, Italy) to explore wolf’s plasticity amid widespread human pressure. To reach this aim, we estimated individual 95% utilisation distributions (UD) after the release and inspected both 95% UDs and net squared displacements to identify individual movement patterns; tested for differences in movement patterns during day and night; and analysed the selection of resting sites during dispersal movement in a highly human-altered environment. Both the 95% UDs and step lengths were smaller for wolves settling in suitable areas than for those settling in more urbanised areas. All wolves exhibited strong temporal segregation with humans during all movement phases, particularly while dispersing across highly urbanised areas. Main roads and proximity to built-up areas were shown to limit wolves’ dispersal, whereas small-wooded patches that provide shelter during rest facilitated long-distance movements. This study provides important insights into wolf movement and settling in urban and peri-urban areas, providing critical knowledge to promote human–carnivore coexistenc

    The Buprestidae (Coleoptera, Buprestoidea) of the Tuscan Archipelago (Italy)

    Get PDF
    Background Buprestidae is a group of beetles of important conservation and phytosanitary value that is poorly studied in the Tuscan Archipelago and the limited faunistic knowledge available refers to a few scant historical records. New information The present contribution increments the species documented in the Archipelago from 27 to 51, providing more than 300 georeferenced occurrence records, derived from both direct field research and citizen science via iNaturalist. Of particular importance is the discovery of Eurythyrea quercus on Isola d'Elba, an uncommon and localised species currently critically endangered

    An unusual presentation of erythema multiforme in a paediatric patient

    Get PDF
    Background: Erythema multiforme (EM) is an acute, vesiculobullous disease of skin and mucous membranes with symptoms ranging from mild to severe. A complex interaction of different factors has been implicated the condition; the majority with a preceding herpes simplex infection. This report describes an unusual presentation of erythema multiforme affecting the lips and oral mucosa of a healthy 7-year-old boy in the form of lip adherence. Case report: Two weeks following eruption of oral ulcerations, a 7-year-old healthy boy developed severe erosive ulceration of both lips, causing complete lip adherence. This was accompanied by marked bilateral submandibular and cervical lymphadenopathy, tremor and sweating. Clinical and laboratory investigations led to a diagnosis of erythema multiforme. The patient was treated initially with gentle application of Vaseline between the lips using cotton buds in an attempt to release lip adhesion, followed by surgical release of the lips under general anaesthesia. Analgesics and topical steroid mouthwash were provided. Follow-up: Seven months later, the patient presented with a recurrence of his EM which included lesions on the skin. The patient was treated with antivirals, topical and systematic steroids to suppress the recurrent attacks of EM. Eighteen months following the initial presentation the patient and parent reported considerable decrease in the frequency, severity and duration of the occurrence of intra-oral ulcers, with no major episode of target lesions on the skin. Conclusion: Erythema multiforme is rare in children, however it should be considered in the differential diagnosis of recurrent erosive oral ulcerative lesions especially when the oral lesions resemble those of primary herpetic gingivostomatitis

    Charting the value and limits of other effective conservation measures (OECMs) for marine conservation: A Delphi study

    Get PDF
    Other effective conservation measures (OECMs) will play an important role in the Post-2020 Global Biodiversity Framework as a way for governments to achieve “30 × 30” (30% protection of land and oceans by 2030). However, the policy tool remains relatively new, is expanding from multiple perspectives, and requires clarification. We conducted a Delphi study – a structured technique designed to elicit the insights of a panel of experts – to chart the value and limits of OECMs for marine conservation. Results of the Delphi reveal a high degree of consensus on several core areas of this emerging policy tool. Experts agreed that OECMs can advance equitable and effective conservation. Realizing these opportunities will require strengthening local and Indigenous rights and prioritizing principles of social equity. The panel also agreed on five key challenges, ranging from ensuring that the burden to prove effectiveness does not fall to local communities to securing adequate resources to support OECMs. In contrast, no consensus was reached on how to measure the effectiveness of OECMs, highlighting the need to develop shared monitoring guidelines. Taken together, these findings outline a clear policy and research agenda to support the contributions of OECMs towards equitable, effective, and enduring conservation
    • …
    corecore