Analyzing Major Track Quality Indices and Introducing a Universally Applicable TQI

Adequate railway track condition is a prerequisite for safe and reliable railway operation. Many track quality indices (TQIs) have been developed with the aim of assessing the track condition holistically. These indices combine measurement signals of some or all relevant geometry parameters with different mathematical models. In this paper, a selection of important TQIs is evaluated. Using measurement data of a five kilometer track section, the indices are calculated and their properties are discussed. This study reveals that all indices exhibit drawbacks to varying degrees. As a consequence, a new index has been developed—the track quality index of Graz University of Technology (TUG_TQI). Its favorable characteristics are presented by means of the above-mentioned test section. The TUG_TQI combines all relevant track geometry parameters, which are normalized beforehand to eliminate over or underrepresentation of different parameters. Thus, the index reliably describes the overall geometrical track quality.

The Genetic Regulation of size Variation in the Transcriptome of the Cerebrum in the Chicken and its role in domestication and brain size evolution

Background: Large difference in cerebrum size exist between avian species and populations of the same species and is believed to reflect differences in processing power. During domestication chickens developed a larger cerebrum compared to their wild progeny, the Red Jungle fowl. The underlying mechanisms that control cerebrum size and the extent to which genetic regulation is similar across brain regions is not well understood. In this study, we combine measurement of cerebrum size with genome-wide genetical genomics analysis to identify the genetic architecture of the cerebrum, as well as compare the regulation of gene expression in this brain region with gene-expression in other regions of the brain (the hypothalamus) and somatic tissue (liver). Results: We identify one candidate gene that putatively regulates cerebrum size ( MTF2 ) as well as identified a large number of eQTL that regulate the transcriptome in cerebrum tissue, with the majority of these eQTL being trans-acting. The overall regulation of gene expression variation in the cerebrum was markedly different to the hypothalamus, with relatively few eQTL in common. In comparison, the cerebrum tissue shared more eQTL with a distant tissue (liver) than with a neighboring tissue (hypothalamus). Conclusion: The candidate gene for cerebrum size ( MTF2 ) has previously been linked to brain development making it a good candidate for further investigation as a regulator of inter-population variation in cerebrum size. The lack of shared eQTL between the two brain regions implies that genetic regulation of gene expression appears to be relatively independent between the two brain regions and suggest that co-evolution between these two brain regions might be more functionally driven than developmental. These findings have relevance for current brain size evolution theories.

Low-Dose and Scatter-Free Cone-Beam CT Imaging Using a Stationary Beam Blocker in a Single Scan: Phantom Studies

Excessive imaging dose from repeated scans and poor image quality mainly due to scatter contamination are the two bottlenecks of cone-beam CT (CBCT) imaging. Compressed sensing (CS) reconstruction algorithms show promises in recovering faithful signals from low-dose projection data but do not serve well the needs of accurate CBCT imaging if effective scatter correction is not in place. Scatter can be accurately measured and removed using measurement-based methods. However, these approaches are considered unpractical in the conventional FDK reconstruction, due to the inevitable primary loss for scatter measurement. We combine measurement-based scatter correction and CS-based iterative reconstruction to generate scatter-free images from low-dose projections. We distribute blocked areas on the detector where primary signals are considered redundant in a full scan. Scatter distribution is estimated by interpolating/extrapolating measured scatter samples inside blocked areas. CS-based iterative reconstruction is finally carried out on the undersampled data to obtain scatter-free and low-dose CBCT images. With only 25% of conventional full-scan dose, our method reduces the average CT number error from 250 HU to 24 HU and increases the contrast by a factor of 2.1 on Catphan 600 phantom. On an anthropomorphic head phantom, the average CT number error is reduced from 224 HU to 10 HU in the central uniform area.

Evaluation of Systems for Quantitation of Autoradiograms,

Automated systems for the evaluation of autoradiograms were compared with the traditional method of manual counting. The automated systems included televison image analysis systems, reflectance/densitometric systems, and semiautomatic digitizing pad systems. Highly automated analysis systems were considered applicable for quantitation of autoradiograms when the subcellular location of the radioactivity is not an important consideration, when background is low, and when operator interaction with the system can be kept at a minimum. In many cases the relationship between silver grains and cell compartments is important for interpretation of the results. Under these conditions, the most rapid, reproducible and reliable method would combine measurement of cellular dimensions with a digitizing pad and manual counting of silver grains by the observer. Such a system should be connected to a computer for formatting and statistical evaluation of the data. Initial testing of a quantitative autoradiographic technique indicated that the autoradiographic slide is a reliable estimator of the radioactivity present in the tissue of experimental animals injected with tritium labeled compounds. Accuracy in counting was lost when silver grains became coincident. Thus, a system for the quantitation of silver grains in relation to cellular morphology requires careful selection of exposure time, computer assisted measurement of cellular dimensions, operator evaluation of silver grains and computerized statistical analysis of the data.