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In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single χ along with an e + e − pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼ 4π acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n → p + e - + ν̅ e decays. The summed kinetic energy ( E e + e − ) from such events is reconstructed and used to set limits, as a function of the χ mass, on the branching fraction for this decay channel.

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A 0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A 0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A 0 .

Treatment in heart failure could be guided by additional non-clinical measures, such as neurohumoral levels. Variability in heart rate is known to reflect neurohumoral stimulation. With this in mind, we sought to assess retrospectively the variability in heart rate to guide the treatment of infants in heart failure. We analysed retrospectively the data from 20 infants with a significant left-to-right shunt. All were unsuitable for cardiac surgery or interventional therapy at the time the treatment had commenced. None of the infants improved while receiving diuretics, spironolactone, and digoxin alone, but improved after the addition of propanolol or metoprolol. None of the infants had problems during or after the subsequent operation. Parasympathetic activity reflected by parameters of variability in heart rate, such as the square root of adjacent RR-intervals, and the amount of adjacent RR-intervals greater than 50 milliseconds, improved in nearly all infants during beta blockade. On the other hand, parameters of variability in heart rate reflecting sympathetic activity did not change. Parasympathetic activity reflected the clinical state of nearly all the infants. These parameters, therefore, seem to be a good non-clinical parameter, showing the optimal treatment for heart failure in an ambulatory setting.

The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the \\(\\beta\\)-decay asymmetry parameter, \\(A_0\\), for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their \\(\\beta\\)-decay electrons are detected with \\(\\approx 4\\pi\\) acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to \\(b_{n}\\), the Fierz interference term in the neutron \\(\\beta\\)-decay rate. In this work, we determine \\(b_{n}\\) from the energy dependence of \\(A_0\\) using the data taken during the UCNA 2011-2013 run. In addition, we present the same type of analysis using the earlier 2010 \\(A\\) dataset. Motivated by improved statistics and comparable systematic errors compared to the 2010 data-taking run, we present a new \\(b_{n}\\) measurement using the weighted average of our asymmetry dataset fits, to obtain \\(b_{n} = 0.066 \\pm 0.041_{\\text{stat}} \\pm 0.024_{\\text{syst}}\\) which corresponds to a limit of \\(-0.012 < b_{n} < 0.144\\) at the 90% confidence level.

The UCNA experiment was designed to measure the neutron \\(\\beta\\)-asymmetry parameter \\(A_0\\) using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for \\(A_0\\) was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008--2009, 2010, and 2011--2013, which ultimately culminated in a 0.67\\% precision result for \\(A_0\\).

The neutron \\(\\beta\\)-decay asymmetry parameter \\(A_0\\) defines the correlation between the spin of the neutron and the momentum of the emitted electron, which determines \\(\\lambda=\\frac{g_{A}}{g_{V}}\\), the ratio of the axial-vector to vector weak coupling constants. The UCNA Experiment, located at the Ultracold Neutron facility at the Los Alamos Neutron Science Center, is the first to measure such a correlation coefficient using ultracold neutrons (UCN). Following improvements to the systematic uncertainties and increased statistics, we report the new result \\(A_0 = -0.12054(44)_{\\mathrm{stat}}(68)_{\\mathrm{syst}}\\) which yields \\(\\lambda\\equiv \\frac{g_{A}}{g_{V}}=-1.2783(22)\\). Combination with the previous UCNA result and accounting for correlated systematic uncertainties produces \\(A_0=-0.12015(34)_{\\mathrm{stat}}(63)_{\\mathrm{syst}}\\) and \\(\\lambda\\equiv \\frac{g_{A}}{g_{V}}=-1.2772(20)\\).

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (\\(\\chi\\)) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single \\(\\chi\\) along with an \\(e^{+}e^{-}\\) pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with \\(\\sim 4\\pi\\) acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). The summed kinetic energy (\\(E_{e^{+}e^{-}}\\)) from such events is used to set limits, as a function of the \\(\\chi\\) mass, on the branching fraction for this decay channel. For \\(\\chi\\) masses consistent with resolving the neutron lifetime discrepancy, we exclude this as the dominant dark matter decay channel at \\(\\gg~5\\sigma\\) level for \\(100~\\text{keV} < E_{e^{+}e^{-}} < 644~\\text{keV}\\). If the \\(\\chi+e^{+}e^{-}\\) final state is not the only one, we set limits on its branching fraction of \\(< 10^{-4}\\) for the above \\(E_{e^{+}e^{-}}\\) range at \\(> 90\\%\\) confidence level.

Marine soundscapes can provide information on the presence of soniferous species and, in some cases, habitat characteristics and biodiversity of certain marine organisms. Tropical back-reefs functioning as nursery areas provide essential fish habitat for juveniles and sub-adults moving to offshore coral reefs as they grow; yet little is known of underwater soundscapes in these habitats. We characterized the soundscapes of 7 artificial patch reefs within a seagrass-dominated, back-reef embayment in The Bahamas. Hydrophones were deployed at each reef and recorded simultaneously for 2 min every 20 min from March to July 2016. Sound pressure levels (SPLs) and acoustic complexity (ACI) were analyzed for low (0.1–1.5 kHz) and high (4–20 kHz) frequency bands to evaluate sounds produced by marine organisms. Low frequency SPLs associated with fish vocalizations peaked twice per day for some reefs, but showed no relationship with habitat complexity or fish community structure. High frequency SPLs and invertebrate snap rates peaked nightly and were positively correlated with structural rugosity of reefs but not fish community structure. ACI values for both high and low frequency bands showed no associations with habitat complexity or fish community structure. These findings suggest that high frequency SPLs and invertebrate snap rates may be more indicative of habitat complexity in back-reef nurseries than low frequency SPLs, and that neither ACI values for low or high frequency bands correlate with fish community structure in areas dominated by juvenile and sub-adult fish.

In 2004, a randomised phase III trial by the European Organisation for Research and Treatment of Cancer (EORTC) and National Cancer Institute of Canada Clinical Trials Group (NCIC) reported improved median and 2-year survival for patients with glioblastoma treated with concomitant and adjuvant temozolomide and radiotherapy. We report the final results with a median follow-up of more than 5 years. Adult patients with newly diagnosed glioblastoma were randomly assigned to receive either standard radiotherapy or identical radiotherapy with concomitant temozolomide followed by up to six cycles of adjuvant temozolomide. The methylation status of the methyl-guanine methyl transferase gene, MGMT, was determined retrospectively from the tumour tissue of 206 patients. The primary endpoint was overall survival. Analyses were by intention to treat. This trial is registered with Clinicaltrials.gov, number NCT00006353. Between Aug 17, 2000, and March 22, 2002, 573 patients were assigned to treatment. 278 (97%) of 286 patients in the radiotherapy alone group and 254 (89%) of 287 in the combined-treatment group died during 5 years of follow-up. Overall survival was 27·2% (95% CI 22·2–32·5) at 2 years, 16·0% (12·0–20·6) at 3 years, 12·1% (8·5–16·4) at 4 years, and 9·8% (6·4–14·0) at 5 years with temozolomide, versus 10·9% (7·6–14·8), 4·4% (2·4–7·2), 3·0% (1·4–5·7), and 1·9% (0·6–4·4) with radiotherapy alone (hazard ratio 0·6, 95% CI 0·5–0·7; p<0·0001). A benefit of combined therapy was recorded in all clinical prognostic subgroups, including patients aged 60–70 years. Methylation of the MGMT promoter was the strongest predictor for outcome and benefit from temozolomide chemotherapy. Benefits of adjuvant temozolomide with radiotherapy lasted throughout 5 years of follow-up. A few patients in favourable prognostic categories survive longer than 5 years. MGMT methylation status identifies patients most likely to benefit from the addition of temozolomide. EORTC, NCIC, Nélia and Amadeo Barletta Foundation, Schering-Plough.