More Evidence for an Oscillation Superimposed on the Hubble Flow

In a recent investigation evidence was presented for a low-level sinusoidal oscillation superimposed on top of the Hubble flow. This oscillation was in V$_{CMB}$, in a sample of type Ia Supernovae sources with accurate distances, and it was found to have a wavelength close to 40 Mpc. It became easily visible after the removal of several previously identified discrete velocity components. Its amplitude like that of the Hubble velocity showed an increase with distance, as would be expected for a constant-amplitude space oscillation. Here we report that this oscillation is also present in distance clumping in these sources, with the same wavelength, but in phase quadrature. The discrete velocity components do not play a role in detecting the distance clumping wavelength. Assuming that time proceeds from high cosmological redshift to low, the blue-shifted velocity peaks, which represent the contraction stage of the velocity oscillation, then lead the density peaks. With the discrete velocity components removed we also find evidence for at least one other, weaker velocity oscillation. It is found to have a wavelength similar to one reported in density clumping by previous investigators. In those cases the source samples were much larger.Comment: 7 pages, with 6 figures, accepted for publication in Astrophysics and Space Scienc

Children\u27s Mental Health over the Early Life Course: The Impact of Economic Resources, Neighborhood Disorder, and Family Processes

Drawing upon a stress process and life course framework, and using data from the Child Supplement of the National Longitudinal Survey of Youth, the three papers presented in this dissertation examine the extent to which economic resources, neighborhood disorder, and family processes influence children’s trajectories of mental health. In the first paper, I empirically construct six categories that represent children with comparable profiles of family income over time: increasing, decreasing, fluctuating, and stability across low-, medium-, and high-income families. The income categories are incorporated in multiple group latent growth curve models to assess the extent to which they initiate and shape children’s mental health trajectories from age 4 to 14. Results reveal significant disparities in antisocial behavior and depression/anxiety at age 4 and over time across the income categories. In the second paper, I use these income categories to examine how stability and change in family income influences trajectories of maternal emotional support and the provision of cognitive stimulation in children’s home environments. In subsequent analyses, I examine the extent to which these different economic profiles moderate the relationship between family processes and children’s mental health trajectories. In the third and final paper, I examine the relationship between stability and change in perceived neighborhood disorder and children’s trajectories of mental health. I conceptualize perceived neighborhood disorder as a two-part process involving a binary component that distinguishes between children exposed to minimal vs. high levels of disorder, and a continuous component that represents the actual level of disorder for children in the latter category. These two processes capture stability and change in neighborhood disorder over time, and are included in parallel process latent growth models to examine their separate and distinct impact on children’s trajectories of mental health. The results from these papers underscore that the duration and sequencing of socioeconomic status, both at the family and neighborhood level, have important implications for children’s mental health and family processes. The results also underscore the complex and dynamic ways family processes influence children’s mental health in different economic contexts

Gene Network Visualization and Quantitative Synteny Analysis of more than 300 Marine T4-Like Phage Scaffolds from the GOS Metagenome

Bacteriophages (phages) are the most abundant biological entities in the biosphere and are the dominant “organisms” in marine environments, exerting an enormous influence on marine microbial populations. Metagenomic projects, such as the Global Ocean Sampling expedition (GOS), have demonstrated the predominance of tailed phages (Caudovirales), particularly T4 superfamily cyanophages (Cyano-T4s), in the marine milieu. Whereas previous metagenomic analyses were limited to gene content information, here we present a comparative analysis of over 300 phage scaffolds assembled from the viral fraction of the GOS data. This assembly permits the examination of synteny (organization) of the genes on the scaffolds and their comparison with the genome sequences from cultured Cyano-T4s. We employ comparative genomics and a novel usage of network visualization software to show that the scaffold phylogenies are similar to those of the traditional marker genes they contain. Importantly, these uncultured metagenomic scaffolds quite closely match the organization of the “core genome” of the known Cyano-T4s. This indicates that the current view of genome architecture in the Cyano-T4s is not seriously biased by being based on a small number of cultured phages, and we can be confident that they accurately reflect the diverse population of such viruses in marine surface waters