We present experimental results from the first systematic study of performance scaling with drive parameters for a magnetoinertial fusion concept. In magnetized liner inertial fusion experiments, the ...burn-averaged ion temperature doubles to 3.1 keV and the primary deuterium-deuterium neutron yield increases by more than an order of magnitude to 1.1 × 1013 (2 kJ deuterium-tritium equivalent) through a simultaneous increase in the applied magnetic field (from 10.4 to 15.9 T), laser preheat energy (from 0.46 to 1.2 kJ), and current coupling (from 16 to 20 MA). Individual parametric scans of the initial magnetic field and laser preheat energy show the expected trends, demonstrating the importance of magnetic insulation and the impact of the Nernst effect for this concept. A drive-current scan shows that present experiments operate close to the point where implosion stability is a limiting factor in performance, demonstrating the need to raise fuel pressure as drive current is increased. Simulations that capture these experimental trends indicate that another order of magnitude increase in yield on the Z facility is possible with additional increases of input parameters.
We report the results from a search for z > 6.5 quasars using the Dark Energy Survey (DES) Year 3 data set combined with the VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey. Our photometric ...selection method is shown to be highly efficient in identifying clean samples of high-redshift quasars, leading to spectroscopic confirmation of three new quasars – VDES J0244-5008 (z = 6.724), VDES J0020-3653 (z = 6.834), and VDES J0246-5219 (z = 6.90) – which were selected as the highest priority candidates in the survey data without any need for additional follow-up observations. Here, we have obtained spectroscopic observations in the near-infrared for VDES J0244-5008 and VDES J0020-3653 as well as our previously identified quasar, VDES J0224-4711 at z = 6.50 from Reed et al. We use the near-infrared spectra to derive virial black hole masses from the full width at half-maximum of the Mg ii line. These black hole masses are ≃1–2 × 109 M⊙. Combined with the bolometric luminosities of these quasars of Lbol ≃ 1–3 × 1047, these imply that the Eddington ratios are high, ≃0.6–1.1. We consider the C iv emission line properties of the sample and demonstrate that our high-redshift quasars do not have unusual C iv line properties when compared to carefully matched low-redshift samples. Our new DES + VHS z > 6.5 quasars now add to the growing census of luminous, rapidly accreting supermassive black holes seen well into the epoch of reionization.
We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with ...expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus B. McKernan, K. E. S. Ford, I. Bartoset al., Astrophys. J. Lett.884, L50 (2019) and is unlikely <O(0.01%)) due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing ora tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated withS190521g, we find plausible values of total mass M(BBH) ∼ 100 Mꙩ, kick velocity v(k) ∼ 200 km/s at θ ∼ 60° in a disk with aspect ratio H/a ∼ 0.01(i.e., disk height H at radius a) and gas density ρ ∼ 10^(−10)g/cu.cm. The merger could have occurred at a disk migration trap (a ∼ 700 r(g); r(g) ≡ GM(SMBH)/sq.c, where M(SMBH) is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼ 1.6 yr(M(SMBH)/10^(8) Mꙩ)(a/10^(3)r(g))^(3/2).
ABSTRACT
We present angular diameter distance measurements obtained by locating the baryon acoustic oscillations (BAO) scale in the distribution of galaxies selected from the first year of Dark ...Energy Survey data. We consider a sample of over 1.3 million galaxies distributed over a footprint of 1336 deg2 with 0.6 < $z$photo < 1 and a typical redshift uncertainty of 0.03(1 + $z$). This sample was selected, as fully described in a companion paper, using a colour/magnitude selection that optimizes trade-offs between number density and redshift uncertainty. We investigate the BAO signal in the projected clustering using three conventions, the angular separation, the comoving transverse separation, and spherical harmonics. Further, we compare results obtained from template-based and machine-learning photometric redshift determinations. We use 1800 simulations that approximate our sample in order to produce covariance matrices and allow us to validate our distance scale measurement methodology. We measure the angular diameter distance, DA, at the effective redshift of our sample divided by the true physical scale of the BAO feature, rd. We obtain close to a 4 per cent distance measurement of DA($z$eff = 0.81)/rd = 10.75 ± 0.43. These results are consistent with the flat Λ cold dark matter concordance cosmological model supported by numerous other recent experimental results.
We estimate total mass (M500), intracluster medium (ICM) mass (MICM), and stellar mass (M*) in a Sunyaev–Zel’dovich effect (SZE) selected sample of 91 galaxy clusters with masses M500 ≳ 2.5 × 1014 M⊙ ...and redshift 0.2 < z < 1.25 from the 2500 deg^2 South Pole Telescope SPT-SZ survey. The total masses M500 are estimatedfrom the SZE observable, the ICM masses MICM are obtained from the analysis of Chandra X-ray observations, and the stellar masses M* are derived by fitting spectral energy distribution templates to Dark Energy Survey griz optical photometry and WISE or Spitzer near-infrared photometry. We study trends in the stellar mass, the ICM mass, the total baryonic mass, and the cold baryonic fraction with cluster halo mass and redshift. We find significant departures from self-similarity in the mass scaling for all quantities, while the redshift trends are all statistically consistent with zero, indicating that the baryon content of clusters at fixed mass has changed remarkably little over the past ≈9 Gyr. We compare our results to the mean baryon fraction (and the stellar mass fraction) in the field, finding that these values lie above (below) those in cluster virial regions in all but the most massive clusters at low redshift. Using a simple model of the matter assembly of clusters from infalling groups with lower masses and from infalling material from the low-density environment or field surrounding the parent haloes, we show that the measured mass trends without strong redshift trends in the stellar mass scaling relation could be explained by a mass and redshift dependent fractional contribution from field material. Similar analyses of the ICM and baryon mass scaling relations provide evidence for the so-called ‘missing baryons’ outside cluster virial regions.
Pelvic floor muscle training (PFMT) is the most commonly used physical therapy treatment for women with stress urinary incontinence (SUI). It is sometimes also recommended for mixed urinary ...incontinence (MUI) and, less commonly, urgency urinary incontinence (UUI).This is an update of a Cochrane Review first published in 2001 and last updated in 2014.
To assess the effects of PFMT for women with urinary incontinence (UI) in comparison to no treatment, placebo or sham treatments, or other inactive control treatments; and summarise the findings of relevant economic evaluations.
We searched the Cochrane Incontinence Specialised Register (searched 12 February 2018), which contains trials identified from CENTRAL, MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP, handsearching of journals and conference proceedings, and the reference lists of relevant articles.
Randomised or quasi-randomised controlled trials in women with SUI, UUI or MUI (based on symptoms, signs or urodynamics). One arm of the trial included PFMT. Another arm was a no treatment, placebo, sham or other inactive control treatment arm.
At least two review authors independently assessed trials for eligibility and risk of bias. We extracted and cross-checked data. A third review author resolved disagreements. We processed data as described in the Cochrane Handbook for Systematic Reviews of Interventions. We subgrouped trials by diagnosis of UI. We undertook formal meta-analysis when appropriate.
The review included 31 trials (10 of which were new for this update) involving 1817 women from 14 countries. Overall, trials were of small-to-moderate size, with follow-ups generally less than 12 months and many were at moderate risk of bias. There was considerable variation in the intervention's content and duration, study populations and outcome measures. There was only one study of women with MUI and only one study with UUI alone, with no data on cure, cure or improvement, or number of episodes of UI for these subgroups.Symptomatic cure of UI at the end of treatment: compared with no treatment or inactive control treatments, women with SUI who were in the PFMT groups were eight times more likely to report cure (56% versus 6%; risk ratio (RR) 8.38, 95% confidence interval (CI) 3.68 to 19.07; 4 trials, 165 women; high-quality evidence). For women with any type of UI, PFMT groups were five times more likely to report cure (35% versus 6%; RR 5.34, 95% CI 2.78 to 10.26; 3 trials, 290 women; moderate-quality evidence).Symptomatic cure or improvement of UI at the end of treatment: compared with no treatment or inactive control treatments, women with SUI who were in the PFMT groups were six times more likely to report cure or improvement (74% versus 11%; RR 6.33, 95% CI 3.88 to 10.33; 3 trials, 242 women; moderate-quality evidence). For women with any type of UI, PFMT groups were two times more likely to report cure or improvement than women in the control groups (67% versus 29%; RR 2.39, 95% CI 1.64 to 3.47; 2 trials, 166 women; moderate-quality evidence).UI-specific symptoms and quality of life (QoL) at the end of treatment: compared with no treatment or inactive control treatments, women with SUI who were in the PFMT group were more likely to report significant improvement in UI symptoms (7 trials, 376 women; moderate-quality evidence), and to report significant improvement in UI QoL (6 trials, 348 women; low-quality evidence). For any type of UI, women in the PFMT group were more likely to report significant improvement in UI symptoms (1 trial, 121 women; moderate-quality evidence) and to report significant improvement in UI QoL (4 trials, 258 women; moderate-quality evidence). Finally, for women with mixed UI treated with PFMT, there was one small trial (12 women) reporting better QoL.Leakage episodes in 24 hours at the end of treatment: PFMT reduced leakage episodes by one in women with SUI (mean difference (MD) 1.23 lower, 95% CI 1.78 lower to 0.68 lower; 7 trials, 432 women; moderate-quality evidence) and in women with all types of UI (MD 1.00 lower, 95% CI 1.37 lower to 0.64 lower; 4 trials, 349 women; moderate-quality evidence).Leakage on short clinic-based pad tests at the end of treatment: women with SUI in the PFMT groups lost significantly less urine in short (up to one hour) pad tests. The comparison showed considerable heterogeneity but the findings still favoured PFMT when using a random-effects model (MD 9.71 g lower, 95% CI 18.92 lower to 0.50 lower; 4 trials, 185 women; moderate-quality evidence). For women with all types of UI, PFMT groups also reported less urine loss on short pad tests than controls (MD 3.72 g lower, 95% CI 5.46 lower to 1.98 lower; 2 trials, 146 women; moderate-quality evidence).Women in the PFMT group were also more satisfied with treatment and their sexual outcomes were better. Adverse events were rare and, in the two trials that did report any, they were minor. The findings of the review were largely supported by the 'Summary of findings' tables, but most of the evidence was downgraded to moderate on methodological grounds. The exception was 'participant-perceived cure' in women with SUI, which was rated as high quality.
Based on the data available, we can be confident that PFMT can cure or improve symptoms of SUI and all other types of UI. It may reduce the number of leakage episodes, the quantity of leakage on the short pad tests in the clinic and symptoms on UI-specific symptom questionnaires. The authors of the one economic evaluation identified for the Brief Economic Commentary reported that the cost-effectiveness of PFMT looks promising. The findings of the review suggest that PFMT could be included in first-line conservative management programmes for women with UI. The long-term effectiveness and cost-effectiveness of PFMT needs to be further researched.
We present the results of a search for rapidly evolving transients in the Dark Energy Survey Supernova Programme. These events are characterized by fast light-curve evolution (rise to peak in ≲10 d ...and exponential decline in ≲30 d after peak). We discovered 72 events, including 37 transients with a spectroscopic redshift from host galaxy spectral features. The 37 events increase the total number of rapid optical transients by more than a factor of two. They are found at a wide range of redshifts (0.05 < z < 1.56) and peak brightnesses (-15.75 > Mg > -22.25). The multiband photometry is well fit by a blackbody up to few weeks after peak. The events appear to be hot (T ≈ 10 000–30 000 K) and large (R ≈ 1014 - 2 × 1015 cm) at peak, and generally expand and cool in time, though some events show evidence for a receding photosphere with roughly constant temperature. Spectra taken around peak are dominated by a blue featureless continuum consistent with hot, optically thick ejecta. We compare our events with a previously suggested physical scenario involving shock breakout in an optically thick wind surrounding a core-collapse supernova, we conclude that current models for such a scenario might need an additional power source to describe the exponential decline. We find that these transients tend to favour star-forming host galaxies, which could be consistent with a core-collapse origin. However, more detailed modelling of the light curves is necessary to determine their physical origin.
Various species of the intestinal microbiota have been associated with the development of colorectal cancer
, but it has not been demonstrated that bacteria have a direct role in the occurrence of ...oncogenic mutations. Escherichia coli can carry the pathogenicity island pks, which encodes a set of enzymes that synthesize colibactin
. This compound is believed to alkylate DNA on adenine residues
and induces double-strand breaks in cultured cells
. Here we expose human intestinal organoids to genotoxic pks
E. coli by repeated luminal injection over five months. Whole-genome sequencing of clonal organoids before and after this exposure revealed a distinct mutational signature that was absent from organoids injected with isogenic pks-mutant bacteria. The same mutational signature was detected in a subset of 5,876 human cancer genomes from two independent cohorts, predominantly in colorectal cancer. Our study describes a distinct mutational signature in colorectal cancer and implies that the underlying mutational process results directly from past exposure to bacteria carrying the colibactin-producing pks pathogenicity island.
The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle ...state's decay rate to the bound states of
C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO
gas, we measure the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers).
Carbon is the fourth-most prevalent element in the Universe and essential for all known life. In the elemental form it is found in multiple allotropes, including graphite, diamond and fullerenes, and ...it has long been predicted that even more structures can exist at pressures greater than those at Earth's core
. Several phases have been predicted to exist in the multi-terapascal regime, which is important for accurate modelling of the interiors of carbon-rich exoplanets
. By compressing solid carbon to 2 terapascals (20 million atmospheres; more than five times the pressure at Earth's core) using ramp-shaped laser pulses and simultaneously measuring nanosecond-duration time-resolved X-ray diffraction, we found that solid carbon retains the diamond structure far beyond its regime of predicted stability. The results confirm predictions that the strength of the tetrahedral molecular orbital bonds in diamond persists under enormous pressure, resulting in large energy barriers that hinder conversion to more-stable high-pressure allotropes
, just as graphite formation from metastable diamond is kinetically hindered at atmospheric pressure. This work nearly doubles the highest pressure at which X-ray diffraction has been recorded on any material.
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