Consecutive Bins Research Articles

Differential representation of auditory categories between cell classes in primate auditory cortex

A comprehensive understanding of the neural mechanisms of cognitive function requires an understanding of how neural representations are transformed across different scales of neural organization: from within local microcircuits to across different brain areas. However, the neural transformations within the local microcircuits are poorly understood. Particularly, the role that two main cell classes of neurons in cortical microcircuits (i.e. pyramidal neurons and interneurons) have in auditory behaviour and cognition remains unknown. In this study, we tested the hypothesis that pyramidal cells and interneurons in the auditory cortex play a differential role in auditory categorization. To test this hypothesis, we recorded single-unit activity from the auditory cortex of rhesus monkeys while they categorized speech sounds. Based on the spike-waveform shape, a neuron was classified as either a narrow-spiking putative interneuron or a broad-spiking putative pyramidal neuron. We found that putative interneurons and pyramidal neurons in the auditory cortex differentially coded category information: interneurons were more selective for auditory categories than pyramidal neurons. These differences between cell classes may be an essential property of the neural computations underlying auditory categorization within the microcircuitry of the auditory cortex.

Chains-into-bins processes

The study of balls-into-bins processes or occupancy problems has a long history. These processes can be used to translate realistic problems into mathematical ones in a natural way. In general, the goal of a balls-into-bins process is to allocate a set of independent objects (tasks, jobs, balls) to a set of resources (servers, bins, urns) and, thereby, to minimize the maximum load. In this paper, we analyze the maximum load for the chains-into-bins problem, which is defined as follows. There are n bins, and m objects to be allocated. Each object consists of balls connected into a chain of length ℓ, so that there are mℓ balls in total. We assume the chains cannot be broken, and that the balls in one chain have to be allocated to ℓ consecutive bins. We allow each chain d independent and uniformly random bin choices for its starting position. The chain is allocated using the rule that the maximum load of any bin receiving a ball of that chain is minimized. We show that, for d⩾2 and m⋅ℓ=O(n), the maximum load is ((lnlnm)/lnd)+O(1) with probability 1−O˜(1/md−1).

MRL and PLS Correlations between the 1H NMR Spectra of Vacuum Residues and the Deasphalting Conditions with the DMO Yields

The areas of signals present in 12 consecutive frequency bins of the 1H nuclear magnetic resonance (NMR) spectra of different vacuum residues (VRs) were correlated with the yield of the deasphalting/demetallization process (DEMEX) under fixed and variable conditions (antisolvent/load ratio and rectification temperature). Prediction models for the demetallized oil (DMO) obtained under variable process conditions generated by partial least squares (PLS) regression had R2 = 0.950 and the CV-q2 was 0.943. Models obtained with multiple linear regression (MLR) for the same process had R2 = 0.93 but with a significantly lower CV-q2 (0.608) value. The prediction models for the DMO yield under a set of fixed conditions was such that R2 = 0.930 for the PLS whereas for the MRL method it was 0.970. Again, the CV-q2 value was higher for the PLS (0.998) than for the MRL method (0.610). The proposed correlation methods are much faster and significantly less costly than the conventional ones used for predicting the yield of the DMO process.

A robust content based audio watermarking using UDWT and invariant histogram

Desynchronization attack is known as one of the most difficult attacks to resist, for it can desynchronize the location of the watermark and hence causes incorrect watermark detection. It is a challenging work to design a robust audio watermarking scheme against desynchronization attacks. Based on undecimated discrete wavelet transform (UDWT) and invariant histogram, we propose a new content based audio watermarking algorithm with good audible quality and reasonable resistance toward desynchronization attacks in this paper. Firstly, the undecimated discrete wavelet transform (UDWT) is performed on original host audio. Secondly, the invariant histogram is extracted from a selected wavelet coefficients range in the low frequency subband. Then, the bin of histogram is divided into many groups, each group including four consecutive bins. For each group, one watermark bit is embedded by reassigning the number of wavelet coefficients in this group of four bins. Finally, the digital watermark is embedded into the original audio signal in UDWT domain by modifying a small set of wavelet coefficients. Simulation results show that the proposed watermarking scheme is not only inaudible and robust against common signal processing operations such as MP3 compression, noise addition, and low-pass filtering etc, but also robust against the desynchronization attacks such as random cropping, time-scale modification, pitch shifting, and jittering etc.

PL.02.01 CSF biomarkers in Alzheimer's disease – use in clinical diagnosis and to monitor treatment effects

Schizophrenia is a common disorder with high heritability and a 10-fold increase in risk to siblings of probands. Replication has been inconsistent for reports of significant genetic linkage. To assess evidence for linkage across studies, rank-based genome scan meta-analysis (GSMA) was applied to data from 20 schizophrenia genome scans. Each marker for each scan was assigned to 1 of 120 30-cM bins, with the bins ranked by linkage scores (1 = most significant) and the ranks averaged across studies (Ravg) and then weighted for sample size ( N[affected cases]). A permutation test was used to compute the probability of observing, by chance, each bin’s average rank (PAvgRnk) or of observing it for a bin with the same place (first, second, etc.) in the order of average ranks in each permutation (Pord). The GSMA produced significant genomewide evidence for linkage on chromosome 2q (PAvgRnk<.000417). Two aggregate criteria for linkage were also met (clusters of nominally significant P values that did not occur in 1,000 replicates of the entire data set with no linkage present): 12 consecutive bins with both PAvgRnk and Pord<.05, including regions of chromosomes 5q, 3p, 11q, 6p, 1q, 22q, 8p, 20q, and 14p, and 19 consecutive bins with Pord<.05, additionally including regions of chromosomes 16q, 18q, 10p, 15q, 6q, and 17q. There is greater consistency of linkage results across studies than has been previously recognized. The results suggest that some or all of these regions contain loci that increase susceptibility to schizophrenia in diverse populations.

Indeterminacy Free Frequency-Domain Blind Separation of Reverberant Audio Sources

Blind separation of convolutive mixtures is a very complicated task that has applications in many fields of speech and audio processing, such as hearing aids and man-machine interfaces. One of the proposed solutions is the frequency-domain independent component analysis. The main disadvantage of this method is the presence of permutation ambiguities among consecutive frequency bins. Moreover, this problem is worst when reverberation time increases. Presented in this paper is a new frequency-domain method, that uses a simplified mixing model, where the impulse responses from one source to each microphone are expressed as scaled and delayed versions of one of these impulse responses. This assumption, based on the similitude among waveforms of the impulse responses, is valid for a small spacing of the microphones. Under this model, separation is performed without any permutation or amplitude ambiguity among consecutive frequency bins. This new method is aimed mainly to obtain separation, with a small reduction of reverberation. Nevertheless, as the reverberation is included in the model, the new method is capable of performing separation for a wide range of reverberant conditions, with very high speed. The separation quality is evaluated using a perceptually designed objective measure. Also, an automatic speech recognition system is used to test the advantages of the algorithm in a real application. Very good results are obtained for both, artificial and real mixtures. The results are significantly better than those by other standard blind source separation algorithms.

Audio watermarking robust against time-scale modification and MP3 compression

In continuation to earlier work where the problem of time-scale modification (TSM) has been studied [S. Xiang, J. Huang, R. Yang, Time-scale invariant audio watermarking based on the statistical features in time domain, in: Proceedings of the 8th Information Hiding Workshop (IH 2006), Lecture Notes in Computer Science, vol. 4437, Springer, Berlin, pp. 93–108] by modifying the shape of histogram extracted from the time domain, here we consider the additional ingredient of resisting common signal processing operations, such as MP3 compression. In other words, we study the problem of the watermark against both TSM and lossy compression. To this end, in this paper we transfer the shape of audio histogram in the time domain to the low-frequency subband by: (i) segmenting an audio signal into portions in reference to the bin width of the time-domain histogram, (ii) concatenating the portions in each bin, and (iii) DWT filtering the concatenation of the portions in each bin. The watermark is inserted by shaping the histogram after the DWT by reassigning population in each group of three consecutive bins. Extensive testing shows that in comparison with the time-domain scheme [S. Xiang, J. Huang, R. Yang, Time-scale invariant audio watermarking based on the statistical features in time domain, in: Proceedings of the 8th Information Hiding Workshop (IH 2006), Lecture Notes in Computer Science, vol. 4437, Springer, Berlin, pp. 93–108], the proposed DWT-based watermarking method is more robust to TSM, MP3 compression, etc.

Segmenting Histogram-based Robust Audio Watermarking Approach

Based on the invariant features and data distribution in time domain before and after attacking on the audio, it is clearly that the standard variance shows good invariant statistical feature. The relation of four consecutive bins in a histogram maintains change less than 5%. Then, a general data selection approach, which meets the demands of normal distribution and other distributions, is created for the watermark hiding. Based on segmenting idea, an audio watermarking algorithm of embedding and extracting is designed with statistical features by the stable relation of four consecutive bins. Experimental results show that the algorithm can resist on attack of low-pass filtering with large hiding bandwidth up to 17 bit/s. It shows much better than the existed histogram approach with relations of three consecutive bins. The algorithm can also resist on the attacks of TSM and other common attacks.

Doubts About Quantal Analysis

to the editor: In an impressive series of articles, Korn and co-workers (e.g., [Faber and Korn 1988][1]; [Faber et al. 1992][2], [1995][3]; [Korn et al. 1981][4], [1982][5], [1987][6]; reviews in [Korn and Faber 1991][7], [2005][8]) described electrophysiological recordings performed on goldfish

Mining airborne particulate size distribution data by positive matrix factorization

Airborne particulate size distribution data acquired in Pittsburgh from July 2001 to June 2002 were analyzed as a bilinear receptor model solved by positive matrix factorization (PMF). The data were obtained from two scanning mobility particle spectrometers and an aerodynamic particle sampler with a temporal resolution of 15 min. Each sample contained 165 size bins from 0.003 to 2.5 μm. Particle growth periods in nucleation events were identified, and the data in these intervals were excluded from this study so that the size distribution profiles associated with the factors could be regarded as sufficiently constant to satisfy the assumptions of the receptor model. The values for each set of five consecutive size bins were averaged to produce 33 new size intervals. Analyses were made on monthly data sets to ensure that the changes in the size distributions from the source to the receptor site could be regarded as constant. The factors from PMF could be assigned to particle sources by examination of the number size distributions associated with the factors, the time frequency properties of the contribution of each source (Fourier analysis of source contribution values), and the correlations of the contribution values with simultaneous gas phase measurements (O3, NO, NO2, SO2, CO) and particle composition data (sulfate, nitrate, organic carbon/elemental carbon). Seasonal trends and weekday/weekend effects were investigated. Conditional probability function analyses were performed for each source to ascertain the likely directions in which the sources were located. Five factors were separated. Two factors, local traffic and nucleation, are clear sources, but each of the other factors appears to be a mixture of several sources that cannot be further separated.

Gene expression fingerprints in human tubulo interstitial inflammation and fibrosis as prognostic markers of disease progression

Schizophrenia is a common disorder with high heritability and a 10-fold increase in risk to siblings of probands. Replication has been inconsistent for reports of significant genetic linkage. To assess evidence for linkage across studies, rank-based genome scan meta-analysis (GSMA) was applied to data from 20 schizophrenia genome scans. Each marker for each scan was assigned to 1 of 120 30-cM bins, with the bins ranked by linkage scores (1 = most significant) and the ranks averaged across studies (Ravg) and then weighted for sample size ( N[affected cases]). A permutation test was used to compute the probability of observing, by chance, each bin’s average rank (PAvgRnk) or of observing it for a bin with the same place (first, second, etc.) in the order of average ranks in each permutation (Pord). The GSMA produced significant genomewide evidence for linkage on chromosome 2q (PAvgRnk<.000417). Two aggregate criteria for linkage were also met (clusters of nominally significant P values that did not occur in 1,000 replicates of the entire data set with no linkage present): 12 consecutive bins with both PAvgRnk and Pord<.05, including regions of chromosomes 5q, 3p, 11q, 6p, 1q, 22q, 8p, 20q, and 14p, and 19 consecutive bins with Pord<.05, additionally including regions of chromosomes 16q, 18q, 10p, 15q, 6q, and 17q. There is greater consistency of linkage results across studies than has been previously recognized. The results suggest that some or all of these regions contain loci that increase susceptibility to schizophrenia in diverse populations.

Genome Scan Meta-Analysis of Schizophrenia and Bipolar Disorder, Part II: Schizophrenia

Schizophrenia is a common disorder with high heritability and a 10-fold increase in risk to siblings of probands. Replication has been inconsistent for reports of significant genetic linkage. To assess evidence for linkage across studies, rank-based genome scan meta-analysis (GSMA) was applied to data from 20 schizophrenia genome scans. Each marker for each scan was assigned to 1 of 120 30-cM bins, with the bins ranked by linkage scores (1 = most significant) and the ranks averaged across studies (R(avg)) and then weighted for sample size (N(sqrt)[affected casess]). A permutation test was used to compute the probability of observing, by chance, each bin's average rank (P(AvgRnk)) or of observing it for a bin with the same place (first, second, etc.) in the order of average ranks in each permutation (P(ord)). The GSMA produced significant genomewide evidence for linkage on chromosome 2q (PAvgRnk<.000417). Two aggregate criteria for linkage were also met (clusters of nominally significant P values that did not occur in 1,000 replicates of the entire data set with no linkage present): 12 consecutive bins with both P(AvgRnk) and P(ord)<.05, including regions of chromosomes 5q, 3p, 11q, 6p, 1q, 22q, 8p, 20q, and 14p, and 19 consecutive bins with P(ord)<.05, additionally including regions of chromosomes 16q, 18q, 10p, 15q, 6q, and 17q. There is greater consistency of linkage results across studies than has been previously recognized. The results suggest that some or all of these regions contain loci that increase susceptibility to schizophrenia in diverse populations.

Binary mapping of cortical spike trains in short-term memory.

Microelectrode studies in monkeys performing short-term memory tasks show the sustained elevated discharge of cortical neurons during the retention of recalled sensory information. Cortical cells that are part of memory networks are assumed to receive numerous inputs of excitatory as well as inhibitory nature and local as well as remote. Thus it is reasonable to postulate that the temporal and spatial summation of diverse inputs on any cell in an activated network will result in temporally discrete groups of spikes in its firing. The activation of a network in active memory supposedly increases the magnitude and diversity of those inputs and thus increases the discontinuities and frequency fluctuations in the firing of cells in the network. In this study we use a new method of analysis that allows the quantification of firing discontinuities in a spike train. We apply it to parietal cells recorded from monkeys during the performance of a tactile short-term memory task. In our method, time is divided into bins of equal duration and the measure of discontinuities is the total count of the number of transitions between consecutive time bins with and without spikes. The results of the analysis show that in many of the cells studied, discontinuities (transitions between spiking and nonspiking) reflect memory-related activity obscured in the measures of raw spike frequency over a wide range of frequencies. These cells show more firing transitions in active short-term memory than in baseline (intertrial) conditions.