The Askaryan Radio Array (ARA) is an ultra-high energy (> 10 17 eV) cosmic neutrino detector in phased construction near the south pole. ARA searches for radio Cherenkov emission from particle cascades induced by neutrino interactions in the ice using radio frequency antennas (∼ 150 − 800 MHz) deployed at a design depth of 200 m in the Antarctic ice. A prototype ARA Testbed station was deployed at ∼ 30 m depth in the 2010-2011 season and the first three full ARA stations were deployed in the 2011-2012 and 2012-2013 seasons. We present the first neutrino search with ARA using data taken in 2011 and 2012 with the ARA Testbed and the resulting constraints on the neutrino flux from 10 17 − 10 21 eV.
Ultra-high energy neutrinos are detectable through impulsive radio signals generated through interactions in dense media, such as ice. Subsurface in-ice radio arrays are a promising way to advance the observation and measurement of astrophysical high-energy neutrinos with energies above those discovered by the IceCube detector (≥ 1 PeV) as well as cosmogenic neutrinos created in the GZK process (≥ 100 PeV). Here we describe the NuPhase detector, which is a compact receiving array of low-gain antennas deployed 185 m deep in glacial ice near the South Pole. Signals from the antennas are digitized and coherently summed into multiple beams to form a low-threshold interferometric phased array trigger for radio impulses. The NuPhase detector was installed at an Askaryan Radio Array (ARA) station during the 2017/18 Austral summer season. In situ measurements with an impulsive, point-source calibration instrument show a 50% trigger efficiency on impulses with voltage signal-to-noise ratios (SNR) of ≤2.0, a factor of ∼1.8 improvement in SNR over the standard ARA combinatoric trigger. Hardware-level simulations, validated with in situ measurements, predict a trigger threshold of an SNR as low as 1.6 for neutrino interactions that are in the far field of the array. With the already-achieved NuPhase trigger performance included in ARASim, a detector simulation for the ARA experiment, we find the trigger-level effective detector volume is increased by a factor of 1.8 at neutrino energies between 10 and 100 PeV compared to the currently used ARA combinatoric trigger. We also discuss an achievable near term path toward lowering the trigger threshold further to an SNR of 1.0, which would increase the effective single-station volume by more than a factor of 3 in the same range of neutrino energies. * Corresponding Author
The Letter describes the design of a versatile analogue building block, termed an operational transresistance amplifier (OTRA). An operational transresistance amplifier has two low-input-impedance terminals and one low-output-impedance terminal. It is found to have a constant bandwidth independent of the gain in most closed-loop configurations. Simulation results are presented to demonstrate the constant-bandwidth performance. As an application example, this amplifier is used to implement a MOSFET-C differentiator, of which analysis and simulation results are also presented.
The studied UV device, with a combination of swirling motion and UVGI, is effective to inactivate airborne S. aureus, P. aeruginosa, and L. pneumophila. This study also explores the factors governing the UVGI and swirling motion against infectious bioaerosols. With understanding the environmental and operational parameters, the studied UV device has the potential to be installed indoors where people are simultaneously present, for example, hospital wards and nursing homes, to prevent the humans from acquiring infectious diseases.
Lactoferrin (LF) in colostral whey was isolated by anti-LF immunoglobulin in yolk (IgY)-Sepharose 4B immunoaffinity chromatography, and parameters such as binding capacity (q m ) and dissociation constant (K d , 3 10 -6 M) of this immunoaffinity gel for LF were discussed. Purification folds for colostral whey I (from colostrum collected within 6 d of postpartum) and colostral whey II (from colostrum collected within 1 d of postpartum) by anti-LF IgY-immunoaffinity chromatography were 135.80 and 103.60, respectively. The recovery for LF in the same colostral whey sample by anti-LF IgY-immunoaffinity chromatography was 82 to 99 %. q m of anti-LF IgY-immunoaffinity gel for LF in colostral whey I and whey II were 0.372 and 0.272 mg LF/mL wet gel, respectively. K d of anti-LF IgY-immunoaffinity gel for LF in colostral whey I was 1.594 × 10 -6 M and II was 1.587 3 10 -6 M.
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