Prey availability and human-carnivore conflict are strong determinants that govern the spatial distribution and abundance of large carnivore species and determine the suitability of areas for their ...conservation. For wide-ranging large carnivores such as cheetahs (Acinonyx jubatus), additional conservation areas beyond protected area boundaries are crucial to effectively conserve them both inside and outside protected areas. Although cheetahs prefer preying on wild prey, they also cause conflict with people by predating on especially small livestock. We investigated whether the distribution of cheetahs' preferred prey and small livestock biomass could be used to explore the potential suitability of agricultural areas in Botswana for the long-term persistence of its cheetah population. We found it gave a good point of departure for identifying priority areas for land management, the threat to connectivity between cheetah populations, and areas where the reduction and mitigation of human-cheetah conflict is critical. Our analysis showed the existence of a wide prey base for cheetahs across large parts of Botswana's agricultural areas, which provide additional large areas with high conservation potential. Twenty percent of wild prey biomass appears to be the critical point to distinguish between high and low probable levels of human-cheetah conflict. We identified focal areas in the agricultural zones where restoring wild prey numbers in concurrence with effective human-cheetah conflict mitigation efforts are the most immediate conservation strategies needed to maintain Botswana's still large and contiguous cheetah population.
Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from γ-rays emitted ...by 40K and the 238U and 232Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus at the Sanford Underground Research Facility, Lead, South Dakota, at the 4850-foot level. In order to characterise the cavern background, in-situ γ-ray measurements were taken with a sodium iodide detector in various locations and with lead shielding. The integral count rates (0–3300 keV) varied from 596 Hz to 1355 Hz for unshielded measurements, corresponding to a total flux from the cavern walls of 1.9±0.4 $γ$ cm-2s-1. The resulting activity in the walls of the cavern can be characterised as 220±60 Bq/kg of 40K, 29±15 Bq/kg of 238U, and 13±3 Bq/kg of 232Th.
Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from γ-rays emitted ...by 40K and the 238U and 232Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus at the Sanford Underground Research Facility, Lead, South Dakota, at the 4850-foot level. In order to characterise the cavern background, in-situ γ-ray measurements were taken with a sodium iodide detector in various locations and with lead shielding. The integral count rates (0–3300 keV) varied from 596 Hz to 1355 Hz for unshielded measurements, corresponding to a total flux from the cavern walls of 1.9±0.4 $γ$ cm-2s-1. The resulting activity in the walls of the cavern can be characterised as 220±60 Bq/kg of 40K, 29±15 Bq/kg of 238U, and 13±3 Bq/kg of 232Th.
The LUX-ZEPLIN (LZ) experiment will enable a neutrinoless double β decay search in parallel to the main science goal of discovering dark matter particle interactions. We report the expected LZ ...sensitivity to Xe136 neutrinoless double β decay, taking advantage of the significant (>600 kg) Xe136 mass contained within the active volume of LZ without isotopic enrichment. After 1000 live-days, the median exclusion sensitivity to the half-life of Xe136 is projected to be 1.06×10^{26} years (90% confidence level), similar to existing constraints. We also report the expected sensitivity of a possible subsequent dedicated exposure using 90% enrichment with Xe136 at 1.06×10^{27 }years.
LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. ...Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4×10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3×10-43 cm2 (7.1×10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020.
The LUX-ZEPLIN (LZ) experiment will enable a neutrinoless double beta decay search in parallel to the main science goal of discovering dark matter particle interactions. We report the expected LZ ...sensitivity to \(^{136}\)Xe neutrinoless double beta decay, taking advantage of the significant (\(>\)600 kg) \(^{136}\)Xe mass contained within the active volume of LZ without isotopic enrichment. After 1000 live-days, the median exclusion sensitivity to the half-life of \(^{136}\)Xe is projected to be 1.06\(\times\)10\(^{26}\) years (90% confidence level), similar to existing constraints. We also report the expected sensitivity of a possible subsequent dedicated exposure using 90% enrichment with \(^{136}\)Xe at 1.06\(\times\)10\(^{27}\) years.
Accurate on-site identification of appropriate alien clearing methods can realize significant cost savings for heterogenous sites. We developed a cost-based model accounting for site parameters such ...as infestation density, slope, obstructive vegetation density and site-access. These parameters are combined with a unit-costing sub-module to identify the most cost-effective clearing method for a particular site. The model was tested in the heterogenous Cape Fynbos biome of South Africa for three clearing methods for Pinus: traditional felling, drill-and-fill, and the arial-basal bark application (ABBA) method. The model accounts for the above-mentioned site parameters after which it is calibrated with the unit-costing for each method. Various scenarios consisting of different combinations of above-mentioned site parameters are then applied to identify the cost-effective solution for any particular combination of site parameters. Results favoured the drill-and-fill method in most cases, with the ABBA method reserved for sites with isolated Pines situated in dense fynbos with difficult access at slope gradients of 45° and higher. At these site combinations, ground teams experience longer walk times which reduces their productivity to such an extent that ABBA is comparatively more cost-effective. Traditional felling turned out to be prohibitively expensive because of team composition (mandatory higher safety and supervision requirements required for chainsaw operations) and slower on-site walking due to heavier equipment. The information enables site managers to do more accurate planning since the model will ensure that a cost-effective method is chosen for any particular site. It is then up to the manager to implement the chosen clearing method in a cost-efficient way.
•We demonstrate the cost of failing to clearly differentiate between cost effectiveness and - efficiency in invasive tree clearing.•We design a model that determines site parameter thresholds for different clearing methods to ensure cost effective clearing choices.•We calculate clearing cost for two new chemical control methods.•Our model enables site managers to choose the most cost-effective management option given site characteristics.
In socially monogamous species, individuals can use extra‐pair paternity and offspring sex allocation as adaptive strategies to ameliorate costs of genetic incompatibility with their partner. ...Previous studies on domesticated Gouldian finches (Erythrura gouldiae) demonstrated a genetic incompatibility between head colour morphs, the effects of which are more severe in female offspring. Domesticated females use differential sex allocation, and extra‐pair paternity with males of compatible head colour, to reduce fitness costs associated with incompatibility in mixed‐morph pairings. However, laboratory studies are an oversimplification of the complex ecological factors experienced in the wild and may only reflect the biology of a domesticated species. This study aimed to examine the patterns of parentage and sex ratio bias with respect to colour pairing combinations in a wild population of the Gouldian finch. We utilized a novel PCR assay that allowed us to genotype the morph of offspring before the morph phenotype develops and to explore bias in morph paternity and selection at the nest. Contrary to previous findings in the laboratory, we found no effect of pairing combinations on patterns of extra‐pair paternity, offspring sex ratio or selection on morphs in nestlings. In the wild, the effect of morph incompatibility is likely much smaller, or absent, than was observed in the domesticated birds. Furthermore, the previously studied domesticated population is genetically differentiated from the wild population, consistent with the effects of domestication. It is possible that the domestication process fostered the emergence (or enhancement) of incompatibility between colour morphs previously demonstrated in the laboratory.
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