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Saturated hydraulic conductivity (Ksat) is a key performance variable in nature-based solutions for managing stormwater such as bioretention. Ksat is well understood from a soils perspective, but not an ecological one, despite growing recognition that plant traits and soil characteristics influence one-another and may co-regulate Ksat. There are myriad plant traits that potentially influence Ksat, which makes it difficult to know where attention should be focused to inform hydrologic design. We address this knowledge gap by 1) evaluating adaptive strategy theory as an overarching framework for characterizing plant effects on Ksat, assessing fifteen bioretention systems across three U.S. states and 2), exploring the implications of this theory for spatial and temporal patterns in plant effects on Ksat driven by regional variability in planting guidance and trajectories of plant succession. Our results illustrate that adaptive strategy significantly influences Ksat, with ruderal plants tending to decrease it and stress tolerant or competitive/stress tolerant plants increasing it. These relationships are indirect, reflecting the impact of adaptive strategy on root traits and soil organic matter, which influence Ksat directly. When these relationships are evaluated in the context of established planting guidance, we find that plants recommended in arid climates tend to increase Ksat relative to bare filter media whereas plants in humid climates do not. Small biases in planting preferences can dramatically change these outcomes. For instance, established vegetation in our bioretention sites was more competitive/stress tolerant than expected, significantly increasing Ksat. We also find that plant effects on Ksat are likely to vary in response to ruderal recruitment as bioretention systems age, reducing Ksat up to 15 %. Collectively, these results illustrate that plants play an important role in bioretention hydrology, and warrant consideration during hydrologic design. They also suggest that adaptive strategy theory is a promising design tool, providing useful insights into plant effects on Ksat, both geographically and over time. 

Abstract The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of $$^{136}$$ 136 Xe. Out of its 50 t total natural xenon inventory, 40 t will be the active target of a time projection chamber which thus contains about 3.6 t of $$^{136}$$ 136 Xe. Here, we show that its projected half-life sensitivity is $$2.4\times {10}^{27}\,{\hbox {year}}$$ 2.4 × 10 27 year , using a fiducial volume of 5 t of natural xenon and 10 year of operation with a background rate of less than 0.2 events/(t  $$\cdot $$ ·  year) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in $$^{136}$$ 136 Xe. 

Abstract We detail the sensitivity of the proposed liquid xenon DARWIN observatory to solar neutrinos via elastic electron scattering. We find that DARWIN will have the potential to measure the fluxes of five solar neutrino components: pp , $$^7$$ 7 Be, $$^{13}$$ 13 N, $$^{15}$$ 15 O and pep . The precision of the $$^{13}$$ 13 N, $$^{15}$$ 15 O and pep components is hindered by the double-beta decay of $$^{136}$$ 136 Xe and, thus, would benefit from a depleted target. A high-statistics observation of pp neutrinos would allow us to infer the values of the electroweak mixing angle, $$\sin ^2\theta _w$$ sin 2 θ w , and the electron-type neutrino survival probability, $$P_{ee}$$ P ee , in the electron recoil energy region from a few keV up to 200 keV for the first time, with relative precision of 5% and 4%, respectively, with 10 live years of data and a 30 tonne fiducial volume. An observation of pp and $$^7$$ 7 Be neutrinos would constrain the neutrino-inferred solar luminosity down to 0.2%. A combination of all flux measurements would distinguish between the high- (GS98) and low-metallicity (AGS09) solar models with 2.1–2.5 $$\sigma $$ σ significance, independent of external measurements from other experiments or a measurement of $$^8$$ 8 B neutrinos through coherent elastic neutrino-nucleus scattering in DARWIN. Finally, we demonstrate that with a depleted target DARWIN may be sensitive to the neutrino capture process of $$^{131}$$ 131 Xe. 

Abstract The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector.