Study of the reactione + e −→K + K − in the energy range1350 \leqq \sqrt s \leqq 2400 MeV

Thee ⁺ e ^?→K ⁺ K ^? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ^± form factor |F _F ^±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.     

Radiative decay ofJ/ψ into γ π+ π−

The radiative decayJ/ψ → γ π⁺ π^? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe ⁺e^? storage rings at Orsay. The π⁺ π^? mass spectrum shows a cleanf ₂ (1270) signal, and the possible presence of two other states at thef ₂ (1720) andf ₄ (2030) masses. For thef ₂ (1270), the branching ratio BR(J/ψ →γf)xBR(f→π⁺ π^?) is measured to be (7.50±0.30±1.12)×10^?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed.     

A proton spin–lattice relaxation rate and nuclear Overhauser effect investigation of the stereochemistry of some 1-aryl derivatives of 1,2-dihydro-s-triazines

Proton spin–lattice relaxation rates (R₁ values) have been measured, at 400 MHz, for a number of 2-methyl- and 2,2-dimethyl-substituted 4,6-diamino-1-aryl-1,2-dihydro-S-triazines. These compounds have high barriers to internal rotation about the aryl C? N bond, and exist in solution as mixtures of enantiomeric or diastereomeric rotational isomers. Diastereotopically related 2-methyl groups in enantiomeric rotamers, and 2-methyl and 2-methine protons in diastereomeric rotamers, typically have different relaxation rates. In favourable circumstances this information may be used to identify the individual rotamers. Unequivocal direct identification of rotamers may be obtained from nuclear Overhauser effect difference spectra.     

Non-planar smoulder propagation governed by diffusion

The steady propagation of a thin smouldering front in a half-spacehas been considered. A suitable coordinate transformation hasallowed the region near the leading edge of the front to beexamined for both a maintained planar surface and with surfacecollapse due to material shrinkage. The change in the oxidizerconcentration for a small increment in the propagation speedfor large time and surface collapse has been determined. Theinfluence of two types of nonlinear diffusion on the shape ofthe smouldering front has been found; other cases can be dealtwith in a similar manner.     

Minimum Message Length in Hybrid ARMA and LSTM Model Forecasting

Modeling and analysis of time series are important in applications including economics, engineering, environmental science and social science. Selecting the best time series model with accurate parameters in forecasting is a challenging objective for scientists and academic researchers. Hybrid models combining neural networks and traditional Autoregressive Moving Average (ARMA) models are being used to improve the accuracy of modeling and forecasting time series. Most of the existing time series models are selected by information-theoretic approaches, such as AIC, BIC, and HQ. This paper revisits a model selection technique based on Minimum Message Length (MML) and investigates its use in hybrid time series analysis. MML is a Bayesian information-theoretic approach and has been used in selecting the best ARMA model. We utilize the long short-term memory (LSTM) approach to construct a hybrid ARMA-LSTM model and show that MML performs better than AIC, BIC, and HQ in selecting the model—both in the traditional ARMA models (without LSTM) and with hybrid ARMA-LSTM models. These results held on simulated data and both real-world datasets that we considered.We also develop a simple MML ARIMA model.     

Sulfonato-encapsulated bismuth(III) oxido-clusters from Bi2O3 in water under mild conditions

Treatment of Bi(2)O(3) with the acids; S-(+)-10-camphorsulfonic, 2,4,6-mesitylenesulfonic and sulfamic, under sonication at room temperature in water for 2-4 h, results in the formation and subsequent crystallisation of polynuclear bismuth oxido-clusters; [Bi(18)O(12)(OH)(12)(O(3)S-Cam)(18)(H(2)O)(2)], [Bi(38)O(45)(O(3)S-Mes)(24)(H(2)O)(14)] and [Bi(6)O(4)(OH)(4)(O(3)SNH(2))(6)].     

The bias of lag window estimators of the fractional difference parameter

An approximation for the bias in lag window estimators of the degree of differencing in, fractionally integrated time series models is derived. The expression obtained is compared with the observed bias from simulations for various windows.     

Doubly stochastic models with GARCH innovations

A rapid development of time series models and methods addressing volatility in computational finance and econometrics are recently reported in the financial literature. This paper considers doubly stochastic volatility models with GARCH errors. General properties for process mean, variance and kurtosis are derived as these results can be used in model identification.     

Equation of state and structural changes in diaminodinitroethylene under compression

Structural changes in 1,1-diamino-2,2-dinitroethylene (DADNE, FOX-7) compressed to high pressure in diamond anvil cells were investigated using angle-dispersive x-ray diffraction analysis, Raman spectroscopy, and optical polarizing microscopy. The x-ray results show several changes above 1 GPa. When the x-ray data are indexed according to the ambient-pressure structure, DADNE shows anisotropic compression, with higher compression along the b axis than along the a or c axis. An ambient-temperature isothermal equation of state of DADNE was generated from these data. In addition, the experimentally obtained Raman spectra were matched with vibrational normal modes calculated using quantum chemistry calculations. The shifts in vibrational modes indicate changes in H-wagging vibrations with pressure.