A novel element upstream of the Vgamma2 gene in the murine T cell receptor gamma locus cooperates with the 3 enhancer to act as a locus control region.

Transgenic expression constructs were employed to identify a cis-acting transcription element in the T cell receptor (TCR)-gamma locus, called HsA, between the Vgamma5 and Vgamma2 genes. In constructs lacking the previously defined enhancer (3E(Cgamma1)), HsA supports transcription in mature but not immature T cells in a largely position-independent fashion. 3E(Cgamma1), without HsA, supports transcription in immature and mature T cells but is subject to severe position effects. Together, the two elements support expression in immature and mature T cells in a copy number-dependent, position-independent fashion. Furthermore, HsA was necessary for consistent rearrangement of transgenic recombination substrates. These data suggest that HsA provides chromatin-opening activity and, together with 3E(Cgamma1), constitutes a T cell-specific locus control region for the TCR-gamma locus

Modulation of the Curie Temperature in Ferromagnetic/Ferroelectric Hybrid Double Quantum Wells

We propose a ferromagnetic/ferroelectric hybrid double quantum well structure, and present an investigation of the Curie temperature (Tc) modulation in this quantum structure. The combined effects of applied electric fields and spontaneous electric polarization are considered for a system that consists of a Mn \delta-doped well, a barrier, and a p-type ferroelectric well. We calculate the change in the envelope functions of carriers at the lowest energy sub-band, resulting from applied electric fields and switching the dipole polarization. By reversing the depolarizing field, we can achieve two different ferromagnetic transition temperatures of the ferromagnetic quantum well in a fixed applied electric field. The Curie temperature strongly depends on the position of the Mn \delta-doped layer and the polarization strength of the ferroelectric well.Comment: 9 pages, 5 figures, to be published in Phys. Rev. B (2006) minor revision: One of the line types is changed in Fig.

An Electronic Mach-Zehnder Quantum Eraser

We propose an electronic quantum eraser in which the electrons are injected into a mesoscopic conductor at the quantum Hall regime. The conductor is composed of a two-path interferometer which is an electronic analogue of the optical Mach-Zehnder interferometer, and a quantum point contact detector capacitively coupled to the interferometer. While the interference of the output current at the interferometer is shown to be suppressed by the which-path information, we show that the which-path information is erased by the zero-frequency cross correlation measurement between the interferometer and the detector output leads. We also investigate a modified setup in which the detector is replaced by a two-path interferometer.We show that the path distinguishability and the visibility of the joint detection can be controlled in a continuous manner, and satisfy a complementarity relation for the entangled electrons.Comment: 5 pages, 2 figure

Perception difference for approaching and receding sound sources of a listener in motion in architectural sequential spaces

This study investigates the dynamic auditory perception in large sequential public spaces for listeners in motion with a stationary primary sound source. Virtual soundwalks, involving four music and voice sources and validated with in situ soundwalks, were conducted in an exhibition space. The perception differences between the approaching and receding sound sources were explored, and three major effects were found. The rising sound received a higher rating in each room with a greater perceived change in the loudness than the falling sound despite equal changes in both levels (approach effect). The difference was greater for the room connected to the source room. The loudness in the room connected to the source room receives a sharp drop (plummet effect) for the receding sound source, which was larger for music than for voice. The effect of the background sound impairing the perceptual priority of rising sound was profound in the receiving rooms. The loudness patterns could not be extended to other perceptual attributes, including reverberation. An increasing symmetry of the overall perception between the different sound source types was observed (convergence effect) either by the approaching or receding sound sources. The overall asymmetry of the directional aspects occurring with the noise and voice was not as distinguishable as with music

Sound environment in an urban apartment building during and after the COVID-19 lockdown

Quiet areas, such as quiet communities, are encouraged to maintain a harmonious and peaceful urban living environment, and the design approach has drawn increasing attention in recent years. Related residential standards define the thresholds of quietness concerning noise pollution problems. However, the variations in height across floors of high-rise buildings and time in sound environments have not been detailed. The city of Shanghai experienced a citywide lockdown to contain the spread of COVID-19 showing the evidence of quietness with marked reductions in anthropogenic noise. Here, we conducted noise monitoring in a 14-story apartment building surrounded and shielded by other buildings in a typical urban community during and after lockdown. The mean value of the equivalent continuous A-weighted sound pressure level (LAeq) of all 14 floors after lockdown was higher than that during lockdown, and the differences were 3.6 and 3.1 dB during the daytime and night-time periods, respectively. The LAeq values at low heights were slightly lower than those at high heights during and after lockdown. The variations due to the different heights were not great. However, the change tendency from the ground to the top floors was similar and correlated during and after lockdown. The difference between the maximum and minimum values of the floors was 3 dB during the daytime period and 4.5 to 5.1 dB during the night-time period. The day equivalent continuous A-weighted sound pressure level (Lday) and night equivalent continuous A-weighted sound pressure level (Lnight) at the middle building height increased 4.0 and 1.3 dB, respectively, after lockdown. The LAeq change tendency during a daily cycle during and after lockdown was similar and highly correlated. The differences in the frequency characteristics of noise level were larger within the 63 to 2,000 Hz range. We suggest that the building represents a typical quiet living condition in high-density habitats in China. Notably, the difference is approximately 3 to 4 dB, and the patterns of variation in height and time are similar between the absence and limited presence of anthropogenic noise. In practice, it would be useful to consider specific floor level or time of day

Subjective evaluation of sequential spaces

The problem of designing non-acoustic sequential spaces is drawing increasing attention from acoustic researchers and practitioners. For subjective evaluation, the effects of sound source, differences in two directions (either towards or away from a sound source), and factors correlated to acoustic comfort remain unknown. This study employed soundwalk and field measurements with a questionnaire survey of a combination of room acoustics and soundscape indicators in two comparative sequential spaces with similar spatial compositions. The sound source resulted in changes to the perceived loudness, spaciousness, and reverberation. Loudness and reverberation showed a similar tendency. Other indicators, including clarity, listener envelopment, intimacy, warmth, acoustic comfort, annoyance, directivity, and overall impression were not affected. Moving in two directions resulted in different loudness and listener envelopment in the same room, both of which were stronger when moving towards the sound source. Even under the condition of a large spatial difference and a 6 dBA sound level difference, the difference in acoustic comfort in sequential spaces could be only about 0.1. The correlations between acoustic comfort and room acoustics indicators varied with the direction of movements

Sound attenuation and reverberation in sequential spaces: An experimental study

Sequential spaces are a spatial system comprising a series of single spaces connected in sequence by openings. They are not uncommon in the built environment and have similar acoustic characteristics with long and coupled spaces. To explore the sound attenuation and reverberation in such spaces, nine in situ measurements were conducted to examine the effects imposed by four factors, namely, opening on separating partition, number of separating partitions, source position, and acoustic absorption. Results revealed that if more rooms were connected by openings, although there could be significant changes in the distribution of sound pressure level, the resulting difference on the average level of each room is almost unobservable in the connecting rooms. In addition, T20 of each room decreases in the source and receiving rooms, especially in the rooms with a larger source distance. According to the source position, the level difference between adjacent rooms by the first separating partition is larger than those in the successive ones when the space is divided by different number of separating partitions in the same construction. A larger source–opening distance results in a larger level difference across the spaces unless the source is placed along the opening. Increasing acoustic absorption in some rooms did not affect the level difference between those unincreased rooms