Bipedal steps in the development of rhythmic behavior in humans

We contrast two related hypotheses of the evolution of dance: H1: Maternal bipedal walking influenced the fetal experience of sound and associated movement patterns; H2: The human transition to bipedal gait produced more isochronous/predictable locomotion sound resulting in early music-like behavior associated with the acoustic advantages conferred by moving bipedally in pace. The cadence of walking is around 120 beats per minute, similar to the tempo of dance and music. Human walking displays long-term constancies. Dyads often subconsciously synchronize steps. The major amplitude component of the step is a distinctly produced beat. Human locomotion influences, and interacts with, emotions, and passive listening to music activates brain motor areas. Across dance-genres the footwork is most often performed in time to the musical beat. Brain development is largely shaped by early sensory experience, with hearing developed from week 18 of gestation. Newborns reacts to sounds, melodies, and rhythmic poems to which they have been exposed in utero. If the sound and vibrations produced by footfalls of a walking mother are transmitted to the fetus in coordination with the cadence of the motion, a connection between isochronous sound and rhythmical movement may be developed. Rhythmical sounds of the human mother locomotion differ substantially from that of nonhuman primates, while the maternal heartbeat heard is likely to have a similar isochronous character across primates, suggesting a relatively more influential role of footfall in the development of rhythmic/musical abilities in humans. Associations of gait, music, and dance are numerous. The apparent absence of musical and rhythmic abilities in nonhuman primates, which display little bipedal locomotion, corroborates that bipedal gait may be linked to the development of rhythmic abilities in humans. Bipedal stimuli in utero may primarily boost the ontogenetic development. The acoustical advantage hypothesis proposes a mechanism in the phylogenetic development

Lateral coherence properties of broad-area semiconductor quantum well lasers

The lateral coherence of broad-area lasers fabricated from a GaAs/GaAlAs graded index waveguide separate confinement and single quantum well heterostructure grown by molecular-beam epitaxy was investigated. These lasers exhibit a high degree of coherence along the junction plane, thus producing a stable and very narrow far field intensity distribution

Tunable effective g-factor in InAs nanowire quantum dots

We report tunneling spectroscopy measurements of the Zeeman spin splitting in InAs few-electron quantum dots. The dots are formed between two InP barriers in InAs nanowires with a wurtzite crystal structure grown by chemical beam epitaxy. The values of the electron g-factors of the first few electrons entering the dot are found to strongly depend on dot size and range from close to the InAs bulk value in large dots |g^*|=13 down to |g^*|=2.3 for the smallest dots. These findings are discussed in view of a simple model.Comment: 4 pages, 3 figure

An M-theory solution generating technique and SL(2,R)

In this paper we generalize the O(p+1,p+1) solution generating technique (this is a method used to deform Dp-branes by turning on a NS-NS B-field) to M-theory, in order to be able to deform M5-brane supergravity solutions directly in eleven dimensions, by turning on a non zero three form A. We find that deforming the M5-brane, in some cases, corresponds to performing certain SL(2,R) transformations of the Kahler structure parameter for the three-torus, on which the M5-brane has been compactified. We show that this new M-theory solution generating technique can be reduced to the O(p+1,p+1) solution generating technique with p=4. Further, we find that it implies that the open membrane metric and generalized noncommutativity parameter are manifestly deformation independent for electric and light-like deformations. We also generalize the O(p+1,p+1) method to the type IIA/B NS5-brane in order to be able to deform NS5-branes with RR three and two forms, respectively. In the type IIA case we use the newly obtained solution generating technique and deformation independence to derive a covariant expression for an open D2-brane coupling, relevant for OD2-theory.Comment: 24 pages, Latex. v2:Sections 3.2 and 3.3 improved. v3:Some clarifications added. Version published in JHE

Entanglement Scaling in the One-Dimensional Hubbard Model at Criticality

We derive exact expressions for the local entanglement entropy E in the ground state of the one-dimensional Hubbard model at a quantum phase transition driven by a change in magnetic field h or chemical potential u. The leading divergences of dE/dh and dE/du are shown to be directly related to those of the zero-temperature spin and charge susceptibilities. Logarithmic corrections to scaling signal a change in the number of local states accessible to the system as it undergoes the transition.Comment: 4+ pages, 2 figures. Fig. 2 and minor typos correcte

Does export dependency hurt economic development? Empirical evidence from Singapore

A rapid export growth in East Asia was once identified as a source of the sustainable economic development that the region enjoyed. However, the current global recession has turned exports from an economic virtue to a vice. There is a growing awareness that a heavy reliance on exports has caused a serious economic downturn in the region. The present paper chooses Singapore as a case study to examine the relationship between the origin of the East Asian Miracle (i.e. export dependency) and the economic growth. For this purpose, the study employs a causality test developed by Toda and Yamamoto. The empirical findings indicate that despite a negative long-run relationship between export dependency and economic growth, Singapore's heavy reliance on exports does not seem to have produced negative effects on the nation's economic growth. This is because the increase in export dependency was an effect, and not a cause, of the country's output expansion.