The disappearance of a narrow Mg II absorption system in quasar SDSS J165501.31+260517.4

In this letter, we present for the first time, the discovery of the disappearance of a narrow Mg II $\lambda\lambda2796,2803$ absorption system from the spectra of quasar SDSS J165501.31+260517.4 ($z_{\rm e}=1.8671$). This absorber is located at $z_{\rm abs} =1.7877$, and has a velocity offset of $8,423\rm ~km~s^{-1}$ with respect to the quasar. According to the velocity offset and the line variability, this narrow Mg II $\lambda\lambda2796,2803$ absorption system is likely intrinsic to the quasar. Since the corresponding UV continuum emission and the absorption lines of another narrow Mg II $\lambda\lambda2796,2803$ absorption system at $z_{\rm abs}=1.8656$ are very stable, we think that the disappearance of the absorption system is unlikely to be caused by the change in ionization of absorption gas. Instead, it likely arises from the motion of the absorption gas across the line of sight

Analysis of Admixed Animals using Indirect Haplotype Information from Existing Technologies

The use of genotyping and sequencing technologies in genetic studies typically involves inspecting variants defined within a single reference genome. While this definition of genetic variation promotes a simple model of the genome that is easy to organize and analyze, it does not encompass the full breadth of variation possible between individuals. Fortunately, existing technologies capture information about genomic variation outside the original targeted variants. By incorporating these low-level signals, which classical methods generally regard as noise, we can make more accurate inferences about the relationship between admixed animals and their ancestral and parental strains. In this thesis, I use both genotyping microarrays and RNA sequencing data to demonstrate the utility of using signals from ancestral haplotype data to analyze admixed animals. I introduce a novel method for designing a genotyping microarray that provides maximal information about ancestral haplotypes for the admixed population Collaborative Cross (CC). The result is the 78K-marker MegaMUGA array, which achieves high call rates and distinction power in a diverse set of mouse strains. Using probe intensities from microarrays such as the MegaMUGA, I develop methods for founder haplotype inference as well as quantitative trait loci (QTL) mapping. I show that these intensity-based methods outperform traditional genotype call-based methods due to their ability to capture additional information about the local sequence, which I confirm using high-throughput sequencing data within probe regions. In addition to demonstrating my thesis with microarray intensity data, I also use RNA-seq read data from parental strains to estimate allele-specific expression (ASE) in the F1 offspring. By directly using parental read data as features in a regularized regression problem, I can achieve accurate estimations of the offspring's expressed gene transcripts and allele-specific expression levels, showing that no matter the data source, incorporating low-level signals directly from ancestral strains provides a more accurate template for analysis of admixed strains.Doctor of Philosoph

The shear characteristic and failure mechanism study of infilled rock joints with constant normal load

In order to evaluate the shear deformation characteristics, the direct shear tests for the rock-like specimens with regular sawtooth were carried out in the laboratory. The different asperity angles and different normal stress conditions were considered and the dilatancy characteristics and the corresponding failure modes were analyzed accordingly. The uncommon asperity angle of 25°, 40° and 55° have been selected to compare with the common angles, which can study the differences in detail. Studies show that when the normal stress keeps constant, the peak shear strength increases first and decreases with the increasing asperity angle afterwards. It is because the force causing sawtooth damage under tensile failure is less than the force under shear failure. When the asperity angle keeps constant, the greater the normal stress, the greater the peak shear strength. The larger the normal displacement of dilatancy angle and dilatancy are caused by larger asperity angle. According to the verification, the test results are in good agreement with the analytical results. It should be noted that the analytical results presented locate below the test result curves, which is due to the small values of c and m in the formula. The sliding failure is usually induced when the asperity angle or the normal stress is small. On the contrary, the tensile damage normally occurs while the asperity angle is large enough