Collision induced absorption in CO2 at 0.091 cm-1

Collision induced microwave absorption has been studied at 0.091 cm -1 and 293 K up to 60 amagat density. Expressing the dielectric loss ε" in the form ε" = Aνρ2(1 - Bp), where ν is the frequency in cm-1 and p is the density, we find A = 0.22 × 10-7 (cm.amagat-2) and B = 0.008 2 (amagat -1). As a result the molecular quadrupole moment of CO2 is calculated to be 5.6 × 10-26 (esu).On étudie l'absorption induite par collisions à 0,091 cm-1 et 293 K, jusqu'à la densité de 60 amagat. En exprimant les pertes diélectriques ε" sous la forme ε" = Aνρ2(1 - Bp), ν étant la fréquence en cm-1 et p la densité, nous trouvons A = 0,22 × 10-7 (cm. amagat-2) et B = 0,008 2 (amagat -1). A la suite de cette étude, le moment quadrupolaire de la molécule CO2 est calculé et trouvé égal à 5,6 × 10-26 (esu)

ENTROTUNER: A Computational Method Adopting the Musician's Interaction with the Instrument to Estimate its Tuning

Archeomusicologists commonly use methods based on the physical properties and the relative tuning system of a musical instrument in order to estimate its tones. However, because the musician often alters the tones' frequency, for example, while playing in wind instruments by means of embouchure or by stressing the string in string instruments, the current methods that neglect the musician's interaction with the instrument cannot provide solid results. In this work, we introduce ENTROTUNER, a computational method, based on mathematical optimization, to more accurately estimate the generated tones by considering: the instrument as a sound production mechanism, the relevant musical scale(s), and the musician's interaction with the instrument. We simulate this interaction as a system that, by following tuning rules, aims to maximize the partials' overlap (harmonicity), coded as entropy's minimization of the aggregated tones' spectrum. Last, we put ENTROTUNER into practice for the ancient Greek wind instrument Aulos. The results reveal that, compared with the traditional methods, ENTROTUNER highlights increased harmonicity (entropy decreased by 0.341bits), eleven additional consonant intervals, as well as 47.8% more tuning quality for the musical instrument. © 2013 IEEE

Physical Modeling of the Ancient Greek Wind Musical Instrument Aulos: A Double-Reed Exciter Linked to an Acoustic Resonator

We present a simulation method for the auralization of the ancient Greek double-reed wind instrument Aulos. The implementation is based on Digital Signal Processing and physical modeling techniques for the instrument's two parts: the excitation mechanism and the acoustic resonator with toneholes. Single-reeded instruments are in-depth studied firstly because their excitation mechanism is the one used in a great amount of modern wind-reed instruments and secondly because the physics governing the phenomena is less complicated than the double-reeded instruments. We here provide a detailed model of a system comprised of a double-reed linked to an acoustic resonator with toneholes to sonify Aulos. We validate our results by comparing our method's synthesized signal with recordings from a replica of Aulos of Poseidonia built in our lab. The comparison showed that the fundamental frequencies and the first three odd harmonics of the signals differ 6, 5, 3, and 2 cents on average, respectively, which is below the Just Noticeable Difference threshold. © 2013 IEEE

Perspective-taking in blindness: An event- related brain potentials study with the continuous wavelet transform

This study presents brain electrophysiological characteristics of perspective-taking for blind individuals ver. sighted ones, aiming to extend our knowledge on social concept formation with visual sensory modality loss. A blind and a sighted group instructed to consider the moral dilemmas therein from a neutral (observer), a morally positive or a negative stance, after the auditory presentation of Aesop's fables. We recorded the basic emotions evoked by every stance in each fable, and the late positive potentials (LPP) component of Event-Related Potential detected with Continuous Wavelet Transform, believed to reflect the sustained attention and stimuli encoding processes. Blind participants demonstrated: i) significantly attenuated LPP amplitudes at distributed brain areas, particularly at leads T3, P4, O2, T6, Cz, Pz, CPz and CP4 (p values 0.026-0.003), ii) prolonged LPP latencies at parietal areas, at leads CP4 (p=0.009), Pz (p=0.019), and P4 (p=0.023), iii) shorter latencies at the frontal area (lead FPz, p=0.026) and iv) significantly shorter latencies at the right posterior centrotemporal area under the negative than the positive condition (lead C4, p=0.009). Both groups exhibited higher LPP amplitudes under the morally positive, and lower under the negative condition located at the parietal areas (P3, p=0.001 and CPz, p=0.013). The relationships between behavior and LPP activation conform to the proposed generation and modulation of LPP. Our findings suggest that the visually deprived cortex may become more responsive to processes associated with perspective-taking, possibly through compensatory plasticity enabling cross-modal reorganization. Thus, the study introduces a novel model for accessing the sustained attention and stimulus-encoding processes underlying perspective-taking. © 2013 IEEE