A practical approach for the design of nonuniform lapped transforms

We propose a simple method for the design of lapped transforms with nonuniform frequency resolution and good time localization. The method is a generalization of an approach previously proposed by Princen, where the nonuniform filter bank is obtained by joining uniform cosine-modulated filter banks (CMFBs) using a transition filter. We use several transition filters to obtain a near perfect-reconstruction (PR) nonuniform lapped transform with significantly reduced overall distortion. The main advantage of the proposed method is in reducing the length of the transition filters, which leads to a reduction in processing delay that can be useful for applications such as real-time audio coding

Coding overcomplete representations of audio using the MCLT

We propose a system for audio coding using the modulated complex lapped transform (MCLT). In general, it is difficult to encode signals using overcomplete representations without avoiding a penalty in rate-distortion performance. We show that the penalty can be significantly reduced for MCLT-based representations, without the need for iterative methods of sparsity reduction. We achieve that via a magnitude-phase polar quantization and the use of magnitude and phase prediction. Compared to systems based on quantization of orthogonal representations such as the modulated lapped transform (MLT), the new system allows for reduced warbling artifacts and more precise computation of frequency-domain auditory masking functions

Reduction of blocking artifacts in both spatial domain and transformed domain

In this paper, we propose a bi-domain technique to reduce the blocking artifacts commonly incurred in image processing. Some pixels are sampled in the shifted image block and some high frequency components of the corresponding transformed block are discarded. By solving for the remaining unknown pixel values and the transformed coefficients, a less blocky image is obtained. Simulation results using the Discrete Cosine Transform and the Slant Transform show that the proposed algorithm gives a better quantitative result and image quality than that of the existing methods

Structural and functional characterization of the yeast general transcriptional activator CCR4

Transcription of the glucose-repressible ADH (ADH2 locus) in Saccharomyces cerevisiae is controlled by two regulatory pathways. The general transcriptional factors CCR4, CRE1, and CRE2 constitute the first pathway while the second pathway is comprised of the trans-activators ADR1 and CCR1. Both ADR1 and CCR1 act through upstream activation sequences (UAS) found in the 5\sp\prime-regulatory region of the ADH2 structual gene. In contrast, the action of CCR4, CRE1, and CRE2 is likely to be at sequences near the TATAA element of ADH2. The CCR4 locus was precisely mapped on the left arm of chromosome I where it had previously been localized. Plasmid constructions bearing sequences from chromosome I in the vicinity of CCR4 were tested for their ability to complement a defective ccr4 allele. A functional copy of CCR4 was identified and the DNA sequenced to reveal a 2511-bp open reading frame that predicts a protein with an estimated mass of 94.6-kDal. The CCR4 protein showed similarity with a family of proteins containing a leucine-rich tandem repeat motif. The repeats are characterized by the 24 amino acid repeating sequence P-X-X-o-X-X-L-X-X-L-X-X-L-X-L-X-X-N-X-o (where X = any residue; o = aliphatic residues L, I, or V) and have been suggested to represent a domain involved in protein binding. Deletion analysis of CCR4 indicates that these repeats are required for its proper function. The amino terminus of CCR4 showed similarities to a variety of transcription factors including TFIID, the TATAA binding factor from humans and Drosophila. Additional studies indicated that CCR4 mRNA and protein levels were not regulated by carbon source availability or the allelic state of the CRE genes. These results suggest that the interactions observed between CCR4 and the CRE genes occur directly or indirectly at a protein level. The possible role that CCR4 plays in the transcriptional regulation of the ADH2 locus based on (1) the sequence similarities seen between CCR4 and other proteins and (2) the functional characterization of deletions and disruptions created within the coding sequences of CCR4 are discussed

Bond behavior of fiber reinforced polymer bars under direct pullout conditions

This paper examines the behavior of Eurocrete fiber-reinforced polymer (FRP) bars (glass, carbon, aramid, and hybrid) in concrete under direct pullout conditions. More than 130 cube specimens were tested in direct pullout where no splitting was allowed to develop. In normal concrete, the mode of bond failure of FRP bars was found to differ substantially from that of deformed steel bars because of damage to the resin rich surface of the bar when pullout takes place. Bond strengths developed by carbon fiber-reinforced polymer and glass fiber-reinforced polymer bars appear to be very similar and just below what is expected from deformed steel bars under similar experimental conditions. The load slip curves highlight some of the fundamental differences between steel and FRP materials. This paper reports in detail on the influence of various parameters that affect bond strength and development such as the embedment length, type, shape, surface characteristics, and diameter of the bar as well as concrete strength. The testing arrangement is also shown to influence bond strength because of the “wedging effect” of the bars

Role of Dehydrodiferulates in Maize Resistance to Pests and Diseases

Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular) between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. This review addresses for the first time different studies in which it is established that cross-linking by dehydrodiferulates contributes to maize’s defences to pests and diseases. Dehydrodiferulate cross-links are involved in maize defence mechanisms against insects such as the European, Mediterranean, and tropical corn borers and, storage pest as the maize weevil. In addition, cross-links are also discussed to be involved in genetic resistance of maize to fungus diseases as Gibberella ear and stalk rot. Resistance against insects and fungus attending dehydrodiferulates could go hand in hand. Quantitative trait loci mapping for these cell wall components could be a useful tool for enhancing resistance to pest and diseases in future breeding programs

Type-IV DCT, DST, and MDCT algorithms with reduced numbers of arithmetic operations

We present algorithms for the type-IV discrete cosine transform (DCT-IV) and discrete sine transform (DST-IV), as well as for the modified discrete cosine transform (MDCT) and its inverse, that achieve a lower count of real multiplications and additions than previously published algorithms, without sacrificing numerical accuracy. Asymptotically, the operation count is reduced from ~2NlogN to ~(17/9)NlogN for a power-of-two transform size N, and the exact count is strictly lowered for all N > 4. These results are derived by considering the DCT to be a special case of a DFT of length 8N, with certain symmetries, and then pruning redundant operations from a recent improved fast Fourier transform algorithm (based on a recursive rescaling of the conjugate-pair split radix algorithm). The improved algorithms for DST-IV and MDCT follow immediately from the improved count for the DCT-IV.Comment: 11 page

Defensive changes in maize leaves induced by feeding of Mediterranean corn borer larvae

Bioassays raw data. (XLSX 33 kb