Semiparametric methods for genome-wide linkage analysis of human gene expression data

With the availability of high-throughput microarray technologies, investigators can simultaneously measure the expression levels of many thousands of genes in a short period. Although there are rich statistical methods for analyzing microarray data in the literature, limited work has been done in mapping expression quantitative trait loci (eQTL) that influence the variation in levels of gene expression. Most existing eQTL mapping methods assume that the expression phenotypes follow a normal distribution and violation of the normality assumption may lead to inflated type I error and reduced power. QTL analysis of expression data involves the mapping of many expression phenotypes at thousands or hundreds of thousands of marker loci across the whole genome. An appropriate procedure to adjust for multiple testing is essential for guarding against an abundance of false positive results. In this study, we applied a semiparametric quantitative trait loci (SQTL) mapping method to human gene expression data. The SQTL mapping method is rank-based and therefore robust to non-normality and outliers. Furthermore, we apply an efficient Monte Carlo procedure to account for multiple testing and assess the genome-wide significance level. Particularly, we apply the SQTL mapping method and the Monte-Carlo approach to the gene expression data provided by Genetic Analysis Workshop 15

Southern California Hypocenter Relocation with Waveform Cross-Correlation, Part 2: Results Using Source-Specific Station Terms and Cluster Analysis

We obtain precise relative relocations for more than 340,000 southern California earthquakes between 1984 and 2002 by applying the source-specific station-term (ssst) method to existing P- and S-phase picks and a differential location method to about 208,000 events within similar-event clusters identified with waveform cross-correlation. The entire catalog is first relocated by using existing phase picks, a reference 1D velocity model, and the ssst method of Richards-Dinger and Shearer (2000). We also perform separate relocations of Imperial Valley events by using a velocity model more suited to this region. Next, we apply cluster analysis to the waveform cross-correlation output to identify similar-event clusters. We relocate earthquakes within each similar-event cluster by using the differential times alone, keeping the cluster centroid fixed to its initial ssst location. We estimate standard errors for the relative locations from the internal consistency of differential locations between individual event pairs; these errors are often as small as tens of meters. In many cases the relocated events within each similar-event cluster align in planar features suggestive of faults. We observe a surprising number of such faults at small scales that strike nearly perpendicular to the main seismicity trends. In general, the fine-scale details of the seismicity reveal a great deal of structural complexity in southern California fault systems

NPP VIIRS Geometric Performance Status

Visible Infrared Imager Radiometer Suite (VIIRS) instrument on-board the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) satellite is scheduled for launch in October, 2011. It is to provide satellite measured radiance/reflectance data for both weather and climate applications. Along with radiometric calibration, geometric characterization and calibration of Sensor Data Records (SDRs) are crucial to the VIIRS Environmental Data Record (EDR) algorithms and products which are used in numerical weather prediction (NWP). The instrument geometric performance includes: 1) sensor (detector) spatial response, parameterized by the dynamic field of view (DFOV) in the scan direction and instantaneous FOV (IFOV) in the track direction, modulation transfer function (MTF) for the 17 moderate resolution bands (M-bands), and horizontal spatial resolution (HSR) for the five imagery bands (I-bands); 2) matrices of band-to-band co-registration (BBR) from the corresponding detectors in all band pairs; and 3) pointing knowledge and stability characteristics that includes scan plane tilt, scan rate and scan start position variations, and thermally induced variations in pointing with respect to orbital position. They have been calibrated and characterized through ground testing under ambient and thermal vacuum conditions, numerical modeling and analysis. This paper summarizes the results, which are in general compliance with specifications, along with anomaly investigations, and describes paths forward for characterizing on-orbit BBR and spatial response, and for improving instrument on-orbit performance in pointing and geolocation

Investigation of properties in barium chalcogenides from first-principles calculations

Master'sMASTER OF SCIENC

Measurement of the Band-to-Band Registration of the SNPP VIIRS Imaging System from On-Orbit Data

No abstract availabl