585 research outputs found

    Characterizing a Shallow Groundwater System beneath Irrigated Sugarcane with Electrical Resistivity and Radon (222Rn), Puunene, Hawai

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    In this study, we use a combination of electrical resistivity profiling and radon (222Rn) measurements to characterize a shallow groundwater system beneath the last remaining, largescale sugarcane plantation on Maui, Hawaii. Hawaiian Commercial & Sugar Company has continuously operated a sugarcane plantation on the western flank of Haleakala Volcano since 1878. The sugarcane is irrigated with a combination of surface water brought through tunnels from the wetter, eastern flank of Haleakala Volcano and groundwater from wells within the plantation. To assess the flow of irrigation water through the shallow subsurface, we collected a representative topo-sequence of four 2-D resistivity profiles that sample different topographic and hydrologic settings within the plantation. The profiles show a down-slope-thickening (0 to 20 m), surficial low-resistivity (10-200 Ohm-m) layer extending from the upslope limit of irrigated sugarcane to the lowest elevations of the plantation. At a canal crossing, the low resistivity layer thickens and is less resistive upslope of the canal. Beneath a reservoir at midelevation, the layer thickens to 20 m and curves down slope beneath the reservoir and up to the base of the field beyond. At the base of the slope, the low resistivity layer is 20-m thick below both fields and a second reservoir. An increase in radon concentration in the down-flow direction within the canal system at one location suggests groundwater infiltration into the canal. We attribute the low-resistivity layer to irrigation water that has infiltrated below the root zone and leaked from canals and reservoirs within the plantation. The water flows down slope to the base of the slope and there flows vertically, recharging the basal aquifer. We suggest that seepage from the canals and reservoirs is in part controlled by the local pressure head within the shallow flow system

    All optical tunable RF filter using elemental antimony

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    In the past decade, the proliferation of modern telecommunication technologies, including 5G, and the widespread adoption of the Internet-of-things (IoT) have led to an unprecedented surge in data generation and transmission. This surge has created an escalating demand for advanced signal processing capabilities. Microwave photonic (MWP) processors offer a promising solution to satisfy this unprecedented demand for data processing by capitalising on the high bandwidth and low latency achievable by optical systems. In this work, we introduce an integrated MWP processing unit for all-optical RF filtering using elemental antimony. We exploit the crystallisation dynamics of antimony to demonstrate a photonic leaky integrator, which is configured to operate as a first-order low-pass filter with a bandwidth of 300 kHz and ultra-compact footprint of 16 × 16 μm2. We experimentally demonstrate the implementation of such a filter as an envelope detector to demodulate an amplitude-modulated signal. Finally, a discussion on achieving bandwidth tunability is presented

    ROR-γ drives androgen receptor expression and represents a therapeutic target in castration-resistant prostate cancer.

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    The androgen receptor (AR) is overexpressed and hyperactivated in human castration-resistant prostate cancer (CRPC). However, the determinants of AR overexpression in CRPC are poorly defined. Here we show that retinoic acid receptor-related orphan receptor γ (ROR-γ) is overexpressed and amplified in metastatic CRPC tumors, and that ROR-γ drives AR expression in the tumors. ROR-γ recruits nuclear receptor coactivator 1 and 3 (NCOA1 and NCOA3, also known as SRC-1 and SRC-3) to an AR-ROR response element (RORE) to stimulate AR gene transcription. ROR-γ antagonists suppress the expression of both AR and its variant AR-V7 in prostate cancer (PCa) cell lines and tumors. ROR-γ antagonists also markedly diminish genome-wide AR binding, H3K27ac abundance and expression of the AR target gene network. Finally, ROR-γ antagonists suppressed tumor growth in multiple AR-expressing, but not AR-negative, xenograft PCa models, and they effectively sensitized CRPC tumors to enzalutamide, without overt toxicity, in mice. Taken together, these results establish ROR-γ as a key player in CRPC by acting upstream of AR and as a potential therapeutic target for advanced PCa
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