A Computational Model of Tonal Tension Profile of Chord Progressions in the Tonal Interval Space

In tonal music, musical tension is strongly associated with musical expression, particularly with expectations and emotions. Most listeners are able to perceive musical tension subjectively, yet musical tension is difficult to be measured objectively, as it is connected with musical parameters such as rhythm, dynamics, melody, harmony, and timbre. Musical tension specifically associated with melodic and harmonic motion is called tonal tension. In this article, we are interested in perceived changes of tonal tension over time for chord progressions, dubbed tonal tension profiles. We propose an objective measure capable of capturing tension profile according to different tonal music parameters, namely, tonal distance, dissonance, voice leading, and hierarchical tension. We performed two experiments to validate the proposed model of tonal tension profile and compared against Lerdahl’s model and MorpheuS across 12 chord progressions. Our results show that the considered four tonal parameters contribute differently to the perception of tonal tension. In our model, their relative importance adopts the following weights, summing to unity: dissonance (0.402), hierarchical tension (0.246), tonal distance (0.202), and voice leading (0.193). The assumption that listeners perceive global changes in tonal tension as prototypical profiles is strongly suggested in our results, which outperform the state-of-the-art models.     

Symbiotic bacteria and the structural specializations in the ileum of Cephalotes ants

Light, scanning, and transmission electron microscopy were used to examine the ultramorphology and ultrastructure of the ileum of Cephalotes atratus, Cephalotes clypeatus, and Cephalotes pusillus. Sections along the ileum revealed differences among the three main regions: proximal (or pylorus), medial, and distal. The structural specializations present in the ileum of these three ants have implications especially to the symbiotic bacteria harbored in this region of the digestive tract. The structural similarities are conspicuous for the three species examined, suggesting that this is the pattern adopted by the genus Cephalotes.     

About Approximation Numbers in Function Spaces

Sharp estimates for the approximation numbers of embeddings between the function spacesB^s_pqandF^s_pqon domains are given in a case not thoroughly studied by Edmunds and Triebel. Corresponding sharp estimates are also obtained for the counterparts of that case in the weighted function space setting.     

Structural, electronic, and optical properties of CaCO3 aragonite

Density functional theory ab initio calculations of the structural parameters, electronic structure, carriers effective masses, and optical absorption of the CaCO₃ aragonite polymorph were performed within the local density and generalized gradient approximations, local density approximation (LDA) and generalized gradient approximation (GGA) respectively. A good agreement between the calculated lattice parameters and experimental results was obtained. Both the LDA and GGA results for CaCO₃ aragonite exhibit very close indirect and direct energy gaps, and the computed effective masses are heavy and anisotropic. Two optical absorption regimes related to distinct electronic transitions are predicted by the calculations.     

Sequencing-independent delocalization in a DNA-like double chain with base pairing

The question of whether or not DNA is intrinsically conducting is still a challenge. The ongoing debate on DNA molecules as an electronic material has so far underestimated a key distinction of the system: the role of base pairing in opposition to correlations along each chain. We show that a disordered base paired double chain presents truly or, at least, effectively delocalized states. This effect is irrespective to the sequencing along each chain.     

Recombination centers and the spatial distribution of spontaneous emission in n-type GaAs at high excitation levels

We have investigated the excitation intensity dependence of the spatial distribution of the emission of photoluminescence from heavilly doped n-type GaAs.It was found that above a certain threshold of excitation, maximum emission originated from an anular zone surrounding the point of excitation rather than from that point.This new effect is explained in terms of the quasi Fermi level dependence of the rate of recombination through recombination centers.     

Anderson localization in a disordered chain with a finite nonlinear response time

In this work, we investigate the competition of disorder, nonlinearity and non-adiabatic process on the wave packet dynamics in 1D. We follow the time evolution of the second moment of the wave packet distribution to characterize its spreading behavior. In order to describe the dynamical behavior of one-electron wave packets, we solve a discrete nonlinear Schr?dinger equation which effectively takes into account a diagonal disorder and a nonlinear contribution. Going beyond the adiabatic regime, we consider that the nonlinearity relaxes in time according to a Debye-like law. In the adiabatic regime, it has been recently demonstrated that the interplay of disorder and nonlinearity leads to a sub-diffusive spread of the wave packet. Here, we numerically demonstrate that no sub-diffusive spreading of the second moment of the wave packet distribution takes place when the finite response time of the nonlinearity is taken into account.     

Real Interpolation of Generalized Besov-Hardy Spaces and Applications

In this paper we consider generalized Hardy spaces which include classical Hardy spaces and Hardy-Lorentz spaces as special cases. We give real interpolation results for such spaces. As applications, we solve an interpolation problem for Besov spaces of generalized smoothness and prove the boundedness of pseudodifferential operators acting both in these spaces and in the local Hardy spaces. For the latter spaces, we also obtain wavelet decompositions.     

Infrared and Raman spectra of silica polymorphs from an ab initio parametrized polarizable force field

The general aim of this study is to test the reliability of polarizable model potentials for the prediction of vibrational (infrared and Raman) spectra in highly anharmonic systems such as high temperature crystalline phases. By using an ab initio parametrized interatomic potential for SiO2 and molecular dynamics simulations, we calculate the infrared and Raman spectra for quartz, cristobalite, and stishovite at various thermodynamic conditions. The model is found to perform very well in the prediction of infrared spectra. Raman peak positions are also reproduced very well by the model; however, Raman intensities calculated by explicitly taking the derivative of the polarizability with respect to the atomic displacements are found to be in poorer agreement than intensities calculated using a parametrized "bond polarizability" model. Calculated spectra for the high temperature beta phases, where the role of dynamical disorder and anharmonicities is predominant, are found to be in excellent agreement with experiments. For the octahedral phases, our simulations are able to reproduce changes in the Raman spectra across the rutile-to-CaCl2 transition around 50 GPa, including the observed phonon softening.     

A new indicator of imminent occurrence of drawdown in the stock market

The crashes in financial markets have caught the attention of many researchers since 1929 and several mathematical models have been proposed to try to forecast the occurrence of these events. The main idea in this work is to use a wavelet transform to detect imminent abrupt changes in a financial time series, which may be eventually related to the possibility of a crash. Case studies are conducted using wavelet approaches with data covering pre-crash and post-crash 1929, as well as more recent Hang Seng and IBOVESPA data. The financial crisis of 2008 also is analyzed using this method. These time series provide useful insights into the behavior of wavelet coefficients under the possibility of short term crashes in stock market. However, it is not a trivial task to infer an imminent drawdown by simply examining the pattern of the wavelet transform coefficients. Hence, an index (a real number between 0 and 1) is proposed to aggregate the information provided by the wavelet coefficients. The new index presented good capability of monitoring crashes and drawdown with small error margins, at least in the studied cases.