Experimental structure determination of silver cluster ions (Ag(n) +, 19 < or = n < or = 79)

The structures of mass selected silver cluster cations Ag19 +, Ag38 +, Ag55 +, Ag59 +, Ag75 +, and Ag79 + have been probed at a temperature of 100 K by trapped ion electron diffraction. The structure assignment is carried out by comparison of the experimental scattering intensity with theoretical scattering functions of calculated candidate structures obtained by density functional theory. For the cluster sizes studied the resulting experimental data are invariably best described by structures based on the icosahedral motif, while closed packed structures can be ruled out.     

Regioisomers Differentiation of 5- (and 7)-Oxo-tetrahydro-7 (and 5)H-thiazolo[3,2-a]pyrimidines. NMR Spectroscopic Studies

Abstract

Reaction of 2-aminothiazoline with an aromatic aldehyde and diethylmalonate, in basic medium afforded two kinds of regioisomers: 5-oxo and 7-oxo-tetrahydrothioazolopyrimidines. Assignment of the structures of 5-oxo-7-phenyl-2,3,6,7-tetrahydro-5H -thiazolo[3,2-a] pyrimidine-6-ethylcarboxylate (1) and 7-oxo-5-phenyl-2,3,5,6-tetrahydro-7H -thiazolo[3,2-a] pyrimidine-6-ethylcarboxylate (2) were performed using ¹H and ¹³C NMR spectroscopy, including NOE experiments. For each regioisomer, only R?S? trans-diaxial diastereoisomers were isolated and characterized.     

Tracking outcomes after phonosurgery for sulcus vocalis: a case report

Outcomes data after a surgical or behavioral intervention should be tracked until stability is reached. Often it is unclear how long patients should be followed and at what point an outcome can be considered stable. These issues have implications for treatment decision making, efficacy measurement, and the design of research studies. Vocal function data were collected 24 hours before and at 1, 6, and 12 months after phonosurgery for sulcus vocalis. One data series was collected daily during the first month after surgery, providing a unique opportunity to study voice changes in the immediate postoperative period. The different vocal function indices (acoustic, perceptual, videostroboscopic, aerodynamic, psychosocial) demonstrated a general pattern of improvement after intervention; however, they appeared to reach stability at different times. This report reinforces the value of following patients until complete outcome stability.     

Tsallis entropy measure of noise-aided information transmission in a binary channel

Noise-aided information transmission via stochastic resonance is shown and analyzed in a binary channel by means of information measures based on the Tsallis entropy. The analysis extends the classic reference of binary information transmission based on the Shannon entropy, and also parallels a recent study based on the Rényi entropy. The conditions for a maximally pronounced stochastic resonance identify optimal Tsallis measures. The study involves a correspondence between Tsallis and Rényi information measures, specially relevant to the characterization of stochastic resonance, and establishing that for such effects identical properties are shared in common by both Tsallis and Rényi measures.     

Lamb waves propagation in elastic plane layers with a joint strip

The Lamb waves are used for the ultrasonic characterization of welds because of their relative long-range propagation. In this paper, a simplified model of a weld-strip between two identical semi-infinite elastic layers is investigated. The reflected and transmitted ultrasonic fields are expressed by modal series whose coefficients are obtained by application of orthogonality relation. Comparisons with solutions obtained by finite elements wave propagation simulations are made. The energy balance between the incident and the scattered waves is also used to verify the accuracy of the obtained modal amplitudes.     

Isomeric states in 253No

Isomeric states in ²⁵³No have been investigated by conversion electron and γ -ray spectroscopy with the GABRIELA detection system. The 31μs isomer reported more than 30 years ago is found to decay to the ground state of ²⁵³No by the emission of a 167keV M2 transition. The spin and parity of this low-lying isomeric state are established to be 5/2⁺ . The presence of another longer-lived isomeric state is also discussed.     

Resonance strategies for the belting style: Results of a single female subject study

This study explores resonance strategies used for the belting style and associated vocal fold vibratory patterns, for the vowels /e/, /a/, /i/, and /u/ on G4 and B4-flat. Acoustic spectra of belted vowels and their unoptimized, "speech-like" equivalents were compared. Vocal fold vibratory patterns were quantified using electroglottography. Results show that /a/ is inherently suitable for belting and requires no adjustment. For /e/, F2-H5 tuning was observed. For /i/, F1 was detuned from H1, enhancing also H2. For /u/, both F1 and F2 were raised to accomplish F2-H3 tuning. These results show that the loud, bright sound of the belting style is achieved by the implementation of resonance strategies that enhance higher harmonics. Electroglottography revealed that resonance strategies also result in raising the closed quotient (CQ) above 52%, an apparent threshold value for belting.     

All‐Optical Photonic Band Control in a Quantum Metamaterial

Metamaterials made of periodic collections of dielectric nanorods are considered theoretically. When quantum resonators are embedded within the nanorods, one obtains a quantum metamaterial, whose electromagnetic properties depend upon the state of the quantum resonators. The theoretical model predicts that when the resonators are pumped and reach the inversion regime, the quantum metamaterial exhibits an all‐optical switchable conduction band. The phenomenon can be described by considering the pole stucture of the scattering matrix of the metamaterial.     

The root extraction problem

The Nth root extraction problem for germs of diffeomorphisms is the problem of finding a germ of diffeomorphism such that gN=f, where gN is the Nth iterate of g under composition. Depending on f and on the multiplier of g at the origin there can be formal and analytic obstructions to a solution of the problem. By considering an unfolding of f we explain these obstructions. Indeed each analytic obstruction corresponds to an accumulation of periodic points which, in turn, are an obstruction to taking an Nth root of the unfolding. We apply this to the problem of the section of a curvilinear angle in N equal parts in conformal geometry.     

Coverage Properties of One-Sided Intervals in the Discrete Case and Application to Matching Priors

We consider asymptotic coverage properties of one-sided posterior confidence intervals for discrete distributions, with a unidimensional parameter of interest and a nuisance parameter of arbitrary dimension. In this case, no higher order asymptotic expansion of the frequentist coverage for these intervals is established, unless some randomization is added. We study here the existence of such frequentist expansions and propose simple continuity corrections based on a uniform random vector. This helps in determining a family of matching priors for one sided intervals in the discrete case.