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Recent Submissions
National‐Scale Rainfall‐Triggered Landslide Susceptibility and Exposure in Nepal
(American Geophysical Union (AGU), 2024) Kincey ME, M. E.; Rosser , N. J.; Swirad , Z. M.; Robinson, Tom; Shrestha , R.; Pujara , D. S.; Basyal , G. K.; Densmore , A. L.; Arrell , K.; Oven , K. J.; Dunant , A.
AbstractNepal is one of the most landslide‐prone countries in the world, with year‐on‐year impacts resulting in loss of life and imposing a chronic impediment to sustainable livelihoods. Living with landslides is a daily reality for an increasing number of people, so establishing the nature of landslide hazard and risk is essential. Here we develop a model of landslide susceptibility for Nepal and use this to generate a nationwide geographical profile of exposure to rainfall‐triggered landslides. We model landslide susceptibility using a fuzzy overlay approach based on freely‐available topographic data, trained on an inventory of mapped landslides, and combine this with high resolution population and building data to describe the spatial distribution of exposure to landslides. We find that whilst landslide susceptibility is highest in the High Himalaya, exposure is highest within the Middle Hills, but this is highly spatially variable and skewed to on average relatively low values. Around 4 × 106 Nepalis (∼15% of the population) live in areas considered to be at moderate or higher degree of exposure to landsliding (>0.25 of the maximum), and critically this number is highly sensitive to even small variations in landslide susceptibility. Our results show a complex relationship between landslides and buildings, that implies wider complexity in the association between physical exposure to landslides and poverty. This analysis for the first time brings into focus the geography of the landslide exposure and risk case load in Nepal, and demonstrates limitations of assessing future risk based on limited records of previous events.
Effects of customary egg harvest regimes on hatching success of a culturally important waterfowl species
(Wiley, 2021) Herse , Mark R.; Tylianakis, Jason; Scott , Nigel J.; Brown , Donald; Cranwell , Iaean; Henry , John; Pauling , Craig; McIntosh, Angus; Gormley , Andrew M.; Lyver , Phil O'B.; McPherson J
Customary harvests of wildlife underpin the livelihoods, cultural identities, well-being and ecological knowledge of many Indigenous peoples and local communities (IPLC), whereas government restrictions on harvests can erode these relationships. Supporting IPLC in place-based resource management, including sustainable customary harvests, can aid wildlife, their habitat and the cultures that value them. Using an experiment jointly initiated by the Māori tribe Ngāi Tahu and researchers (Māori and non-Māori) in Aotearoa/New Zealand, we identified low-impact strategies for harvesting black swan (kakī anau, Cygnus atratus) eggs at an important coastal lagoon, Te Waihora/Lake Ellesmere. The experiment tested whether nest-level hatching success (number of eggs hatched) depended on nest-level harvest pressure; whether this effect was additive; and the extent to which harvest influenced post-harvest egg laying and hatching probability, relative to several control variables. Nest-level harvest pressure determined nest-level hatching success and had a non-additive effect on population-level hatching success. Specifically, harvesting one-third or two-thirds of a clutch caused a loss of approximately one hatchling per egg removed, because swans tended to replace few of those harvested eggs and hatching probability of unharvested eggs was generally high (but lower in nests with two-thirds of eggs removed). Conversely, harvesting an entire clutch caused a loss of approximately one hatchling for every two eggs removed, because swans often subsequently re-laid new, albeit smaller, clutches. During fixed-output harvests, removing entire clutches early during nesting could induce re-laying and prevent abandonment of unharvested eggs. Moreover, harvesting from areas of nesting colonies with low nest density, where hatching probability of unharvested eggs was lowest, could limit disturbance. Finally, restoring foraging habitat in degraded wetlands surrounding nutrient-overloaded waterbodies could offset eutrophication effects by providing plant resources that swans require to lay eggs indeterminately. In addition to improving IPLC well-being, implementing strategies such as these could enhance place-based resource management by supporting IPLC engagement with nature, which increases the number and detection resolution of ecological feedbacks (e.g. population numbers, habitat conditions) and resilience to environmental change. Moreover, customary harvest could be a practical, culturally appropriate and less wasteful alternative to non-consumptive culling for mitigating human–wildlife conflict (e.g. waterfowl grazing on pasture). A free Plain Language Summary can be found within the Supporting Information of this article.
Nutrition in Abrupt Sunlight Reduction Scenarios: Envisioning Feasible Balanced Diets on Resilient Foods
(MDPI AG, 2022) Pham , Alix; García Martínez, Juan B.; Brynych , Vojtech; Stormbjorne , Ratheka; Pearce , Joshua M.; Denkenberger, David
Abrupt sunlight reduction scenarios (ASRS) following catastrophic events, such as a nuclear war, a large volcanic eruption or an asteroid strike, could prompt global agricultural collapse. There are low-cost foods that could be made available in an ASRS: resilient foods. Nutritionally adequate combinations of these resilient foods are investigated for different stages of a scenario with an effective response, based on existing technology. While macro-and micronutrient requirements were overall met, some—potentially chronic—deficiencies were identified (e.g., vitamins D, E and K). Resilient sources of micronutrients for mitigating these and other potential deficiencies are presented. The results of this analysis suggest that no life-threatening micronutrient deficiencies or excesses would necessarily be present given preparation to deploy resilient foods and an effective response. Careful preparedness and planning—such as stock management and resilient food production ramp-up—is indispensable for an effective response that not only allows for fulfilling people’s energy requirements, but also prevents severe malnutrition.
For the love of blood: the Roman arena
(2024) Sciarrino, Enrica
Improvements to the estimation of the muon content in cosmic-ray air showers
(2024) Roy, Vagdhan
This study delves into techniques aimed at improving the reconstruction of cosmic-ray properties using signals from the IceTop surface array and planned extensions. The reconstruction of cosmic-ray direction, energy, and mass discrimination involves fitting models to the spatial and temporal distribution of particles observed on the ground. In this investigation, we optimise the Nishimura-Kamata-Greisen (NKG) model and compare its performance with the standard double logarithmic parabola (DLP) model used in IceTop analyses.
The optimized NKG model demonstrates similar performance to the DLP model in estimating primary energy across the majority of studied energy ranges. However, at high energies exceeding 107.2 GeV, the resolution of estimating primary energy for the DLP LDF consistently remains below 12% for all selected primaries. In contrast, for the NKG LDF, the resolution for each primary varies between 10% and 20% for energies exceeding 107.2 GeV. Notably, the NKG model shows no obvious mass bias in the resolution for primary energy, unlike the DLP model; however, it is more unstable at higher energies. This optimised NKG function can be used as a baseline model for future IceTop analyses involving the NKG LDF.
A significant focus of our study is on developing a method to estimate the low-energy muon component of individual showers. Muon measurements are crucial for cosmic-ray mass com- position studies, tests of hadronic interaction models, and addressing the “muon puzzle”. We investigate a two-component lateral distribution function (TwoLDF) with separate descriptions for electromagnetic and muon lateral distributions of detector signals. Using IceTop, the NKG lateral distribution function (LDF) for the electromagnetic component yields a better bias for the estimation of primary energy, whereas the DLP LDF exhibits a better resolution. Additionally, the TwoLDF model with the NKG LDF leads to a better resolution in the low-energy muon number, whereas using the DLP LDF leads to a better bias in the low-energy muon number. The mass-dependent bias in energy reconstruction with the NKG LDF employed for the TwoLDF becomes smaller compared to the case of using the DLP function towards 100 PeV in primary energy. However, a mass-dependent bias is exhibited for smaller energies and needs to be a part of further optimisation. In total, the application of the NKG function within the TwoLDF model constitutes a promising method due to its improvement in low-energy muon number resolution compared to the DLP function.
Furthermore, applying the TwoLDF model for IceCube-Gen2 and IceTop did not allow for a comprehensive quantitative analysis due to instability of the model for the very low multiplicity of hits on IceTop for air showers across the studied energy range. Additionally, the TwoLDF fit purely being performed in a region where silent detectors are dominant contributes to the instability and needs further optimisation.