The fractional quantum Hall effect in infinite layer systems

Stacked two dimensional electron systems in transverse magnetic fields exhibit three dimensional fractional quantum Hall phases. We analyze the simplest such phases and find novel bulk properties, e.g., irrational braiding. These phases host ``one and a half'' dimensional surface phases in which motion in one direction is chiral. We offer a general analysis of conduction in the latter by combining sum rule and renormalization group arguments, and find that when interlayer tunneling is marginal or irrelevant they are chiral semi-metals that conduct only at T > 0 or with disorder.Comment: RevTeX 3.0, 4p., 2 figs with epsf; reference to the detailed companion paper cond-mat/0006506 adde

Increasing speech intelligibility in monaural hearing by adding noise at the other ear

© 2018 Elsevier Ltd Ambient environment noise can affect speech intelligibility in phone communication. This paper investigates the feasibility of increasing speech intelligibility in monaural hearing by adding noise at the other ear. The testing materials were generated by mixing the speech from the English Coordinate Response Measure corpus with three types of environmental noise, where 4 signals to noise ratios in the speech ear and 14 noise levels in the contralateral ear were included. The experimental results show that a proper level of contralateral noise can improve the speech intelligibility when the signal to noise ratio in the speech ear is lower than a certain level, but a large contralateral noise level has the opposite effect. A preliminary explanation for the phenomena is attempted by using a binaural loudness model and some psychoacoustic and physiological facts

LEARNING FROM NOISY SAMPLES FOR MAN-MADE IMPERVIOUS SURFACE MAPPING

Abstract. Man-made impervious surfaces, indicating the human footprint on Earth, are an environmental concern because it leads to a chain of events that modifies urban air and water resources. To better map man-made impervious surfaces in any region of interest (ROI), we propose a framework for learning to map impervious areas in any ROIs from Sentinel-2 images with noisy reference data, using a pre-trained fully convolutional network (FCN). The FCN is first trained with reference data only available in Europe, which is able to provide reasonable mapping results even in areas outside of Europe. The proposed framework, aiming to achieve an improvement over the preliminary predictions for a specific ROI, consists of two steps: noisy training data pre-processing and model fine-tuning with robust loss functions. The framework is validated over four test areas located in different continents with a measurable improvement over several baseline results. It has been shown that a better impervious mapping result can be achieved through a simple fine-tuning with noisy training data, and label updating through robust loss functions allows to further enhance the performances. In addition, by analyzing and comparing the mapping results to baselines, it can be highlighted that the improvement is mainly coming from a decreased omission error. This study can also provide insights for similar tasks, such as large-scale land cover/land use classification when accurate reference data is not available for training

Valosin-containing protein regulates the proteasome-mediated degradation of DNA-PKcs in glioma cells.

DNA-dependent protein kinase (DNA-PK) has an important role in the repair of DNA damage and regulates the radiation sensitivity of glioblastoma cells. The VCP (valosine-containing protein), a chaperone protein that regulates ubiquitin-dependent protein degradation, is phosphorylated by DNA-PK and recruited to DNA double-strand break sites to regulate DNA damage repair. However, it is not clear whether VCP is involved in DNA-PKcs (DNA-PK catalytic subunit) degradation or whether it regulates the radiosensitivity of glioblastoma. Our data demonstrated that DNA-PKcs was ubiquitinated and bound to VCP. VCP knockdown resulted in the accumulation of the DNA-PKcs protein in glioblastoma cells, and the proteasome inhibitor MG132 synergised this increase. As expected, this increase promoted the efficiency of DNA repair in several glioblastoma cell lines; in turn, this enhanced activity decreased the radiation sensitivity and prolonged the survival fraction of glioblastoma cells in vitro. Moreover, the VCP knockdown in glioblastoma cells reduced the survival time of the xenografted mice with radiation treatment relative to the control xenografted glioblastoma mice. In addition, the VCP protein was also downregulated in ~25% of GBM tissues from patients (WHO, grade IV astrocytoma), and the VCP protein level was correlated with patient survival (R(2)=0.5222, P<0.05). These findings demonstrated that VCP regulates DNA-PKcs degradation and increases the sensitivity of GBM cells to radiation

High-temperature electrical and thermal transport properties of fully filled skutterudites RFe_(4)Sb_(12) (R = Ca, Sr, Ba, La, Ce, Pr, Nd, Eu, and Yb)

Fully filled skutterudites RFe_(4)Sb_(12) (R = Ca, Sr, Ba, La, Ce, Pr, Nd, Eu, and Yb) have been prepared and the high-temperature electrical and thermal transport properties are investigated systematically. Lattice constants of RFe_(4)Sb_(12) increase almost linearly with increasing the ionic radii of the fillers, while the lattice expansion in filled structure is weakly influenced by the filler valence charge states. Using simple charge counting, the hole concentration in RFe_(4)Sb_(12) with divalent fillers (R = Ca, Sr, Ba, Eu, and Yb) is much higher than that in RFe4Sb12 with trivalent fillers (R = La, Ce, Pr, and Nd), resulting in relatively high electrical conductivity and low Seebeck coefficient. It is also found that RFe_(4)Sb_(12) filled skutterudites having similar filler valence charge states exhibit comparable electrical conductivity and Seebeck coefficient, and the behavior of the temperature dependence, thereby leading to comparable power factor values in the temperature range from 300 to 800 K. All RFe_(4)Sb_(12) samples possess low lattice thermal conductivity. The correlation between the lattice thermal resistivity WL and ionic radii of the fillers is discussed and a good relationship of W_L ~ (r_(cage)−r_(ion))^3 is observed in lanthanide metal filled skutterudites. CeFe_(4)Sb_(12), PrFe_(4)Sb_(12), and NdFe_(4)Sb_(12) show the highest thermoelectric figure of merit around 0.87 at 750 K among all the filled skutterudites studied in this work

Dual frequency sound absorption with an array of shunt loudspeakers.

Transformer noise is dominated by low frequency components, which are hard to be controlled with traditional noise control approaches. The shunt loudspeaker consisting of a closed-box loudspeaker and a shunt circuit has been proposed as an effective sound absorber by storing and dissipating the electrical energy converted from the incident sound. In this paper, an array of shunt loudspeakers is proposed to control the 100 Hz and 200 Hz components of transformer noise. The prototype under tests has a thickness of 11.8 cm, which is only 1/28 of the wavelength of 100 Hz. The sound absorption performance of the array under random incidence is analyzed with the parallel impedance method, and the arrangement of array elements is optimized. The test results in a reverberation room show that the proposed array has sound absorption coefficients of 1.04 and 0.93 at 100 Hz and 200 Hz, respectively, which provides potential of applying this type of thin absorbers for low-frequency sound control

An experimental study on transfer function estimation using acoustic modelling and singular value decomposition.

Transfer functions relating sound source strengths and the sound pressure at field points are important for sound field control. Recently, two modal domain methods for transfer function estimation have been compared using numerical simulations. One is the spatial harmonic decomposition (SHD) method, which models a sound field with a series of cylindrical waves; while the other is the singular value decomposition (SVD) method, which uses prior sound source location information to build an acoustic model and obtain basis functions for sound field modelling. In this paper, the feasibility of the SVD method using limited measurements to estimate transfer functions over densely spaced field samples within a target region is demonstrated experimentally. Experimental results with various microphone placements and system configurations are reported to demonstrate the geometric flexibility of the SVD method compared to the SHD method. It is shown that the SVD method can estimate broadband transfer functions up to 3099 Hz for a target region with a radius of 0.083 m using three microphones, and allow flexibility in system geometry. Furthermore, an application example of acoustic contrast control is presented, showing that the proposed method is a promising approach to facilitating broadband sound zone control with limited microphones

COMPLEX HUMAN AUDITORY PERCEPTION AND SIMULATED SOUND PERFORMANCE PREDICTION

This paper reports an investigation into the degree of consistency between three different methods of sound performance evaluation through studying the performance of a built project as a case study. The non-controlled office environment with natural human speech as a source was selected for the subjective experiment and ODEON room acoustics modelling software was applied for digital simulation. The results indicate that although each participant may interpret and perceive sound in a particular way, the simulation can pre- dict this complexity to some extent to help architects in designing acoustically better spaces. Also the results imply that architects can make valid comparative evaluations of their designs in an architecturally intuitive way, using architectural language. The research acknowledges that complicated engineering approaches to subjective analysis and to controlling the test environment and participants is difficult for architects to comprehend and implement