46 research outputs found

    The University of Sheffield CHiME-7 UDASE challenge speech enhancement system

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    The CHiME-7 unsupervised domain adaptation speech enhancement (UDASE) challenge targets domain adaptation to unlabelled speech data. This paper describes the University of Sheffield team’s system submitted to the challenge. A generative adversarial network (GAN) methodology based on a conformer-based metric GAN (CMGAN) is employed as opposed to the unsupervised RemixIT strategy used in the CHiME-7 baseline system. The discriminator of the GAN is trained to predict the output score of a Deep Noise Suppression Mean Opinion Score (DNSMOS) metric. Additional data augmentation strategies are employed which provide the discriminator with historical training data outputs as well as more diverse training examples from an additional pseudo-generator. The proposed approach, denoted as CMGAN+/+, achieves significant improvement in DNSMOS evaluation metrics with the best proposed system achieving 3.51 OVR-MOS, a 24% improvement over the baseline

    Study of K0(1430)K^*_0(1430) and a0(980)a_0(980) from BK0(1430)πB\to K^*_0(1430)\pi and Ba0(980)KB\to a_0(980)K Decays

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    We use the decay modes BK0(1430)πB \to K^*_0(1430) \pi and Ba0(980)KB \to a_0(980) K to study the scalar mesons K0(1430)K^*_0(1430) and a0(980)a_0(980) within perturbative QCD framework. For BK0(1430)πB \to K^*_0(1430) \pi, we perform our calculation in two scenarios of the scalar meson spectrum. The results indicate that scenario II is more favored by experimental data than scenario I. The important contribution from annihilation diagrams can enhance the branching ratios about 50% in scenario I, and about 30% in scenario II. The predicted branching ratio of Ba0(980)KB \to a_0(980) K in scenario I is also less favored by the experiments. The direct CP asymmetries in BK0(1430)πB \to K^*_0(1430) \pi are small, which are consistent with the present experiments.Comment: More references are added. Published Versio

    Study of the Decay phi --> eta pi0 gamma with the KLOE detector

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    In a sample of 5.3x10^7 phi-decays observed with the KLOE detector at the Frascati phi-factory Dafne we find 605 eta pi0 gamma events with eta --> gamma\gamma and 197 eta pi0 gamma events with eta --> pi+ pi- pi0. The decay phi --> eta pi0 gamma is dominated by the process phi --> a0 gamma. From a fit to the eta pi0 mass spectrum we find BR(phi --> ao(980) gamma)= (7.4 +- 0.7)x10^-5.Comment: 12 pages, 6 figures, submitted to Phys.Lett.

    Partial wave analysis of J/\psi \to \gamma \phi \phi

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    Using 5.8×107J/ψ5.8 \times 10^7 J/\psi events collected in the BESII detector, the radiative decay J/ψγϕϕγK+KKS0KL0J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L is studied. The ϕϕ\phi\phi invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/c2c^{2}. A partial wave analysis shows that the structure is dominated by a 0+0^{-+} state (η(2225)\eta(2225)) with a mass of 2.240.02+0.030.02+0.032.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02} GeV/c2c^{2} and a width of 0.19±0.030.04+0.060.19 \pm 0.03^{+0.06}_{-0.04} GeV/c2c^{2}. The product branching fraction is: Br(J/ψγη(2225))Br(η(2225)ϕϕ)=(4.4±0.4±0.8)×104Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}.Comment: 11 pages, 4 figures. corrected proof for journa

    New Strategies in Sport Nutrition to Increase Exercise Performance.

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    Despite over 50 years of research, the field of sports nutrition continues to grow at a rapid rate. Whilst the traditional research focus was one that centred on strategies to maximize competition performance, emerging data in the last decade has demonstrated how both macronutrient and micronutrient availability can play a prominent role in regulating those cell signalling pathways that modulate skeletal muscle adaptations to endurance and resistance training. Nonetheless, in the context of exercise performance, it is clear that carbohydrate (but not fat) still remains king and that carefully chosen ergogenic aids (e.g. caffeine, creatine, sodium bicarbonate, beta-alanine, nitrates) can all promote performance in the correct exercise setting. In relation to exercise training, however, it is now thought that strategic periods of reduced carbohydrate and elevated dietary protein intake may enhance training adaptations whereas high carbohydrate availability and antioxidant supplementation may actually attenuate training adaptation. Emerging evidence also suggests that vitamin D may play a regulatory role in muscle regeneration and subsequent hypertrophy following damaging forms of exercise. Finally, novel compounds (albeit largely examined in rodent models) such as epicatechins, nicotinamide riboside, resveratrol, β-hydroxy β-methylbutyrate, phosphatidic acid and ursolic acid may also promote or attenuate skeletal muscle adaptations to endurance and strength training. When taken together, it is clear that sports nutrition is very much at the heart of the Olympic motto, Citius, Altius, Fortius (faster, higher, stronger)

    Study of J/Psi decays into eta Kstar Kstar-bar

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    We report the first observation of \mPJpsi \to \mPeta\mPKst\mAPKst decay in a \mPJpsi sample of 58 million events collected with the BESII detector. The branching fraction is determined to be (1.15±0.13±0.22)×103(1.15 \pm 0.13 \pm 0.22)\times 10^{-3}. The selected signal event sample is further used to search for the \mPY resonance through \mPJpsi \to \mPeta \mPY, \mPY\to\mPKst\mAPKst. No evidence of a signal is seen. An upper limit of \mathrm{Br}(\mPJpsi \to \mPeta \mPY)\cdot\mathrm{Br}(\mPY\to\mPKst\mAPKst) < 2.52\times 10^{-4} is set at the 90% confidence level.Comment: 11 pages, 4 figure

    A Study of J/psi-->gamma gamma V(rho,phi) Decays with the BESII Detector

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    Using a sample of 58×10658\times 10^6 J/ψJ/\psi events collected with the BESII detector, radiative decays J/ψγγVJ/\psi\to\gamma\gamma V, where V=ρV=\rho or ϕ\phi, are studied. A resonance around 1420 MeV/c2^2 (X(1424)) is observed in the γρ\gamma\rho mass spectrum. Its mass and width are measured to be 1424±10(stat)±11(sys)1424\pm 10(stat)\pm 11(sys) MeV/c2^2 and 101.0±8.8±8.8 101.0\pm 8.8 \pm 8.8 MeV/c2^2, respectively, and its branching ratio B(J/ψγX(1424)γγρ)B(J/\psi\to \gamma X(1424)\to \gamma \gamma \rho) is determined to be (1.07±0.17±0.11)×104(1.07\pm0.17 \pm 0.11)\times 10^{-4}. A search for X(1424)γϕX(1424)\to \gamma\phi yields a 95% C.L. upper limit B(J/ψγX(1424)γγϕ)<0.82×104B(J/\psi\to \gamma X(1424)\to \gamma\gamma \phi) < 0.82 \times 10^{-4}.Comment: 10 pages, 5 figures, submitted to PL

    CRDM reliability study. [Control Rod Drive Monitors (CRDM)]

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    During the checkout of the Control Rod Assembly (CRA) control system, a fault occurred which could potentially drive all four CRA's at speeds >2''/min. Subsequent experimental tests were performed to purposely identify attainable rod speeds as a function of supplied voltage. Results indicated a rod speed of up to 29.7''/min was attainable at 100 volts. The LOFT Technical Specifications (Section 3.10.3.1) limit the voltage at the stators of the CRDMs to a maximum of 90 volts which will preclude rod speeds >28''/min with a 95% reliability at a 95% confidence level. In addition, redundant overvoltage monitors (OVMs) were installed in the CRA control system to preclude an overvoltage situation. The purpose of this LTR is to illustrate the probability of achieving an excessive rod speed event (>28''/min) both with and without the OVMs

    Ecophysiology of the soft tree fern, Dicksonia antarctica Labill

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    Environmental constraints on gas exchange, stomatal conductance and water relations were investigated in the Soft Tree Fern, Dicksonia antarctica, at sites across its natural distribution and in the glasshouse. Dicksonia antarctica exhibited strong stomatal response down to a vapour pressure deficit (VPD) of 0.25 kPa, an unusual characteristic when compared with other ground fern species. Net photosynthetic rate may be a response of the microenvironment prevalent during frond development, reflecting acclimatory capacity. Both these ecophysiological characteristics are consistent with the ecological niche of D. antarctica, a long-lived, fire-resistant species that, during its lifetime, may be exposed to: (i) a humid environment beneath a rainforest canopy; and (ii) an exposed environment following wildfire. Maximum net photosynthesis and quantum yield of photosynthesis correlated strongly with VPD and the maximum net photosynthetic rate of 10.8 µmol m−2 s−1 was the highest yet recorded for a fern. These observations are consistent with the relatively low growth typically observed in D. antarctica on sunny, exposed sites and vice versa on cool, humid sites exposed to sunflecks. Favourable water relations maintained under conditions of moderate VPD (2.03 kPa) were probably due to stomatal control. However, inadequate rainfall or high VPD (4.98 kPa) caused water stress, recovery of which was limited by slow water transport through fronds. These observations are consistent with the limitation of D. antarctica distribution to sites sheltered from hot winds and with reliable water supply. The funnel-shaped rosette of fronds of D. antarctica may harvest rainfall and make it accessible to aerial roots situated at the base of fronds. This process may maintain favourable water relations independently of a subterranean root system. This proposed strategy of water acquisition is unique for a fern species and may eliminate a need for soil moisture competition with surrounding plant species. It is suggested that the ecophysiological characteristics observed in D. antarctica in this study may contribute to the ecological niche it occupies, which is characterized by a variable environment
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