Extreme statistics of complex random and quantum chaotic states

Complex random states have the statistical properties of the Gaussian and circular unitary ensemble eigenstates of random matrix theory. Even though their components are correlated by the normalization constraint, it is nevertheless possible to derive compact analytic formulas for their extreme values' statistical properties for all dimensionalities. The maximum intensity result slowly approaches the Gumbel distribution even though the variables are bounded, whereas the minimum intensity result rapidly approaches the Weibull distribution. Since random matrix theory is conjectured to be applicable to chaotic quantum systems, we calculate the extreme eigenfunction statistics for the standard map with parameters at which its classical map is fully chaotic. The statistical behaviors are consistent with the finite-N formulas.     

Thermal conductance of thin silicon nanowires

The thermal conductance of individual single crystalline silicon nanowires with diameters less than 30 nm has been measured from 20 to 100 K. The observed thermal conductance shows unusual linear temperature dependence at low temperatures, as opposed to the T3 dependence predicted by the conventional phonon transport model. In contrast to previous models, the present study suggests that phonon-boundary scattering is highly frequency dependent, and ranges from nearly ballistic to completely diffusive, which can explain the unexpected linear temperature dependence.     

Dissociation of deuteron, <Superscript>6</Superscript>He and <Superscript>11</Superscript>Be from Coulomb dissociation reaction cross-section

The fragmentation of deuteron, ⁶He and ¹¹Be have been studied during interaction with the ²⁰⁸Pb nucleus at various projectile energies. The Coulomb dissociation cross-sections and the momentum distribution of the break-up fragments have been analysed within the framework of the direct fragmentation model. The post-acceleration effect of deuteron during break-up and the halo structures of both the ⁶He and ¹¹Be have been investigated.      

Reproducibility of the quantitative assessment of cartilage morphology and trabecular bone structure with magnetic resonance imaging at 7 T

To assess the reproducibility of quantitative measurements of cartilage morphology and trabecular bone structure of the knee at 7 T, high-resolution sagittal spoiled gradient-echo images and high-resolution axial fully refocused steady-state free-precession (SSFP) images from six healthy volunteers were acquired with a 7-T scanner. The subjects were repositioned between repeated scans to test the reproducibility of the measurements. The reproducibility of each measurement was evaluated using the coefficient(s) of variation (CV). The computed CV were 1.13% and 1.55% for cartilage thickness and cartilage volume, respectively, and were 2.86%, 1.07%, 2.27% and 3.30% for apparent bone volume over total volume fraction (app.BV/TV), apparent trabecular number (app.Tb.N), apparent trabecular separation (app.Tb.Sp) and apparent trabecular thickness (app.Tb.Th), respectively. The results demonstrate that quantitative assessment of cartilage morphology and trabecular bone structure is reproducible at 7 T and motivates future musculoskeletal applications seeking the high-field strength's superior signal-to-noise ratio.     

Stochastic limit-average games are in EXPTIME

The value of a finite-state two-player zero-sum stochastic game with limit-average payoff can be approximated to within in time exponential in a polynomial in the size of the game times polynomial in logarithmic in , for all .     

Theoretical studies on the mechanism of C-P bond cleavage of a model alpha-aminophosphonate in acidic condition

Various reaction paths of the P-C bond cleavage of alpha-aminophosphonates in acidic media, resulting in the derivatives of phosphonic acid, has been investigated using density functional level of theories in the gas phase as well as in aqueous medium. Dimethyl (alpha-anilinobenzyl)phosphonate has been used as the model molecule and our investigation confirms a three steps process including protonation, P-C bond cleavage, and the transformation of the products from the final transition state (imine cation and H-phosphonate) through hydrolysis. The most favorable reaction path starts from the amino group protonation, followed by a proton transfer through N-H...O(P) hydrogen bond, and the P-C bond cleavage from the resulting protonated structure. Explicit inclusion of water molecules indicated that two waters are needed for the P-C bond cleavage, and the calculated mechanistic paths in this hydrated model are similar to those of the aqueous solvation model.     

Mono-oxo bis(dithiolene) Mo(IV)/W(IV) complexes as building blocks for sulfide bridged Bi- and Tri-nuclear complexes

A new electron precise, six-electron, sulfide-bicapped trinuclear cluster complex [Et4N]4[Mo(IV)3(mu3-S)2(mnt)6] (1) has been synthesized, where each Mo(IV) atom is seven coordinated. Identical reaction conditions yielded a dimeric complex, [PNP]2[W(V)2(mu2-S)2(mnt)4] (2) from the starting W(IV) analogue due to oxidation by sulfur formed by the auto-oxidation of H2S. Two stepwise reversible reductions and no oxidation of 2 as observed by cyclic voltammetry are correlated with the nonbonding nature of the lowest unoccupied molecular orbital and deeply buried highest occupied molecular orbital by theoretical calculations at the density-functional theory level.     

Zero Expectile Processes and Bayesian Spatial Regression

We introduce new classes of stationary spatial processes with asymmetric, sub-Gaussian marginal distributions using the idea of expectiles. We derive theoretical properties of the proposed processes. Moreover, we use the proposed spatial processes to formulate a spatial regression model for point-referenced data where the spatially correlated errors have skewed marginal distribution. We introduce a Bayesian computational procedure for model fitting and inference for this class of spatial regression models. We compare the performance of the proposed method with the traditional Gaussian process-based spatial regression through simulation studies and by applying it to a dataset on air pollution in California.     

A Novel Trihybrid Material Based on Renewables: An Efficient Recyclable Heterogeneous Catalyst for C−C Coupling and Reduction Reactions

The generation of organic–inorganic hybrid materials from renewable resources and their utilization in basic and applied areas has been at the forefront of research in recent years for sustainable development. Herein, a novel organic–inorganic trihybrid material was synthesized by in situ generation of palladium nanoparticles (PdNPs) in a hybrid gel matrix based on renewable chemicals. Constituents of the hybrid gel included a pentacyclic triterpenoid arjunolic acid extractable from Terminalia arjuna and the leaf extract of Chrysophyllum cainito rich in flavonoids. We took advantage of the presence of flavonoid molecules in this hybrid gel to generate an advanced trihybrid gel through in situ reduction of doped Pd^II salts to stable PdNPs. The xerogel of this trihybrid material was used as a recyclable heterogeneous catalyst for C?C coupling and reduction reactions in aqueous media. We also demonstrated that the in situ generated PdNPs containing trihybrid material was a more efficient catalyst than the trihybrid material generated with presynthesized PdNPs.     

Estimation of the energy spectrum of cosmic ray electrons at the atmospheric depth (3.8–7.4)g.cm−2

Analytical calculations have been done to estimate the energy spectra of the secondary electrons originated from the decay of charged and neutral pions initiated on the upper atmosphere from the primary nucleon–air interactions in the energy range (4–100) GeV. The calculations are valid up to an atmospheric depth of about (3.8–7.4) g.cm^–2. The derived results are compared with the observed electron fluxes available from the balloon flight experiments of MASS2, HEAT, magnetic spectrometer system of Golden et al., instrument using scintillating fibers of Nishimura et al., and BETS.