Integrative Analysis of Metabolomic,Proteomic and Genomic Data to Reveal Functional Pathways and Candidate Genes for Drip Loss in Pigs

The aim of this study was to integrate multi omics data to characterize underlying functional pathways and candidate genes for drip loss in pigs. The consideration of different omics levels allows elucidating the black box of phenotype expression. Metabolite and protein profiling was applied in Musculus longissimus dorsi samples of 97 Duroc × Pietrain pigs. In total, 126 and 35 annotated metabolites and proteins were quantified, respectively. In addition, all animals were genotyped with the porcine 60 k Illumina beadchip. An enrichment analysis resulted in 10 pathways, amongst others, sphingolipid metabolism and glycolysis/gluconeogenesis, with significant influence on drip loss. Drip loss and 22 metabolic components were analyzed as intermediate phenotypes within a genome-wide association study (GWAS). We detected significantly associated genetic markers and candidate genes for drip loss and for most of the metabolic components. On chromosome 18, a region with promising candidate genes was identified based on SNPs associated with drip loss, the protein “phosphoglycerate mutase 2” and the metabolite glycine. We hypothesize that association studies based on intermediate phenotypes are able to provide comprehensive insights in the genetic variation of genes directly involved in the metabolism of performance traits. In this way, the analyses contribute to identify reliable candidate genes.     

Improved microphotometry by compensating for fluctuations in the illumination

Behind a beam-splitter in the illuminator, the irradiation of an area conjugated to the object plane is measured by a silicon photodiode and used as a reference signal. Analog division of the photomulitplier signal by this reference acts like stabilizing the light source by a factor greater than 25. A technical realization of the optical and electronical components as well as experimental results are described.     

On the asymptotic distribution of the errors in vector quantization

In a recent paper, Lee and Neuhoff (see ibid., vol.42, no.2, p446-60, 1996) found an asymptotic formula for the distribution of the length of the errors produced by a vector quantizer with many quantization points. This distribution depends on the source probability density, the quantizer point density, and the quantizer shape profile. (The latter characterizes the shapes of the quantization cells as a function of position.) The purpose of this paper is to give a rigorous derivation of this formula by identifying precise conditions under which it is shown that if a sequence of vector quantizers with a given dimension and an increasing number of points has “specific” point densities and “specific” shape profiles converging to a “model” point density and a “model” shape profile, respectively, then the distribution of the length of the quantization error, suitably normalized, converges to the aforementioned formula, with the model point density and the model shape profile substituted     

Periodic prefix-synchronized codes: A generating function approach

A generating function method is developed in order to select synchronization markers that maximize the timing span of period-2 periodic prefix-synchronized (PPS) sync-timing coding with small delay. Sync-timing codes are used in situations where conventional data synchronization is required, and data time stamps or time indices are also needed. A PPS code is a sync-timing code in which each encoded block of data is preceded by a synchronization marker, with the markers preceding successive blocks forming a periodic sequence with some period p. Since only PPS codes with small periods can have good rates at small delays, and since codes with p=1 are simply Gilbert's prefix-synchronized codes which have been studied previously in the literature, this paper focuses on p=2 codes. The generating function method, which extends that used by Guibas and Odlyzko to analyze p=1 codes, enables one to find PPS codes with the largest possible timing span among codes with a given delay and rate. It is found that at low delays such optimized PPS codes offer significant advantages over cascaded and natural marker PPS codes. They also compare favorably with embedded-index codes. Finally, for asymptotically large delays, it is shown that the best p=2 PPS codes operate at approximately the same rate and delay, but twice the timing span, of the best p=1 codes.     

Reduced storage VQ via secondary quantization

This paper introduces methods for reducing the table storage required for encoding and decoding with unstructured vector quantization (UVQ) or tree-structured vector quantization (TSVQ). Specifically, a low-storage secondary quantizer is used to compress the code vectors (and test vectors) of the primary quantizer. The relative advantages of uniform and nonuniform secondary quantization are investigated. A Linde-Buzo-Gray (LBG) like algorithm that optimizes the primary UVQ codebook for a given secondary codebook and another that jointly optimizes both primary and secondary codebooks are presented. In comparison to conventional methods, it is found that significant storage reduction is possible (typically a factor of two to three) with little loss of signal-to-noise ratio (SNR). Moreover, when reducing dimension is considered as another method of reducing storage, it is found that the best strategy is a combination of both. The method of secondary quantization is also applied to TSVQ to reduce the table storage required for both encoding and decoding. It is shown that by exploiting the correlation among the test vectors in the tree, both encoder and decoder storage can be significantly reduced with little loss of SNR, by a factor of about four (or two) relative to the conventional method of storing test vectors (or test hyperplanes)     

Delta codes for line drawings

A new class of chain codes for line drawings, named delta codes is introduced. Two specific types of fixed angle delta codes and ring delta codes are described. The area-of-error distortion and rate are calculated for two types of delta codes applied to straight and slowly curving lines, and it is shown that the delta outperforms other chain codes with the same set of link types. For rapidly curving lines, however, the delta codes introduce curvature overload distortion analogous to the slope overload distortion of traditional delta modulation for waveforms     

Printer models and error diffusion

A new model-based approach to digital halftoning is proposed. It is intended primarily for laser printers, which generate "distortions" such as "dot overlap". Conventional methods, such as clustered-dot ordered dither, resist distortions at the expense of spatial and gray-scale resolution. The proposed approach relies on printer models that predict distortions, and rather than merely resisting them, it exploits them to increase, rather than decrease, both spatial and gray-scale resolution. We propose a general framework for printer models and find a specific model for laser printers. As an example of model-based halftoning, we propose a modification of error diffusion, which is often considered the best halftoning method for CRT displays with no significant distortions. The new version exploits the printer model to extend the benefits of error diffusion to printers. Experiments show that it provides high-quality reproductions with reasonable complexity. The proposed modified error diffusion technique is compared with Stucki's (1981) MECCA, which is a similar but not widely known technique that accounts for dot overlap. Model-based halftoning can be especially useful in transmission of high-quality documents using high-fidelity gray-scale image encoders.     

Dynamic frequency change influences loudness perception: A central, analytic process.

Three experiments showed that dynamic frequency change influenced loudness. Listeners heard tones that had concurrent frequency and intensity change and tracked loudness while ignoring pitch. Dynamic frequency change significantly influenced loudness. A control experiment showed that the effect depended on dynamic change and was opposite that predicted by static equal loudness contours. In a 3rd experiment, listeners heard white noise intensity change in one ear and harmonic frequency change in the other and tracked the loudness of the noise while ignoring the harmonic tone. Findings suggest that the dynamic interaction of pitch and loudness occurs centrally in the auditory system; is an analytic process; has evolved to take advantage of naturally occurring covariation of frequency and intensity; and reflects a shortcoming of traditional static models of loudness perception in a dynamic natural setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual coding of images for halftone display

We present a new technique for coding gray-scale images for facsimile transmission and printing on a laser printer. We use a gray-scale image encoder so that it is only at the receiver that the image is converted to a binary pattern and printed. The conventional approach is to transmit the image in halftoned form, using entropy coding (e.g. CCITT Group 3 or JBIG). The main advantages of the new approach are that we can get higher compression rates and that the receiver can tune the halftoning process to the particular printer. We use a perceptually based subband coding approach. It uses a perceptual masking model that was empirically derived for printed images using a specific printer and halftoning technique. In particular, we used a 300 dots/inch write-black laser printer and a standard halftoning scheme ("classical") for that resolution. For nearly transparent coding of gray-scale images, the proposed technique requires lower rates than the standard facsimile techniques.     

Comparison of feed-in tariff, quota and auction mechanisms to support wind power development

A comparison of support schemes for market-based deployment of renewable energy in the UK and Germany shows that the feed-in tariff reduces costs to consumers and results in larger deployment. A survey among project developers suggests two explanations: (1) Site selection presents the biggest obstacle under the feed-in tariff. Uncertain financing of other schemes reduces efforts at initial project stages and planning permits become a major obstacle. (2) Project developers do not compete in price but for good sites under the feed-in tariff. Most importantly, turbine producers and construction services contribute to most of the costs, and face at least equal levels of competition under the feed-in tariff.