The Role of Environment in Galaxy Formation

In this thesis we investigate the influence that environment has on the formation and evolution of galaxies in the Galaxy And Mass Assembly (GAMA) survey. The highly complete equatorial regions of GAMA cover 180 square degrees of the sky, providing spectroscopic redshifts for 180,000 galaxies brighter than m_r = 19.8. GAMA is the largest multi-wavelength spectroscopic survey of its kind to date, designed to study aspects of galaxy formation on scales of <1 Mpc. The dependence of the galaxy luminosity function (LF) on local environment is well described by linear relations with overdensity. The faint end slope of the LF is largely independent of environment but steepens in void regions. The environmental dependence shows little evolution over the last 3 Gyrs, and can again be parameterised by a linear relation when split by colour. The dependence of the LF on the cosmic web classification can be predicted from its dependence on overdensity and the distribution of overdensities within each cosmic web structure. Observations from the GAMA survey can be theoretically interpreted by comparing to predictions made by the semi-analytic galaxy formation model of GALFORM through lightcone mock catalogues, which exhibit the same selection criteria as GAMA. Galaxy groups trace the underlying distribution of dark matter haloes in the Universe, and the use of galaxy group properties to infer the properties of dark matter, such as halo mass, is explored. Measurements of the galaxy density profile in galaxy groups in the GAMA survey and in the lightcone mocks suggest that the GALFORM model predicts the galaxy density profile to be too centrally concentrated. Comparisons to galaxy surveys such as GAMA lead to a bright future for the studies of galaxy formation

Technology for Civic Data Integration

Efforts to collect, manage, transform, and integrate data across administrative systems into actionable knowledge to inform better policy decisions are becoming more common. However, the technical processes, procedures, and infrastructure they employ vary substantially. Variety in approaching data infrastructure, transfer, linking, and security is expected in this emerging field, but both established and developing efforts would benefit from cohesive guidance regarding the technical considerations of data integration, with focus on presenting a range of options that can be weighted based on context specific restrictions (e.g. cost, staffing, or existing infrastructure). Actionable Intelligence for Social Policy (AISP), MetroLab Network, and the National Neighborhood Indicators Partnership (NNIP) with support from the Annie E. Casey Foundation, are convening a working group to shape and develop guidance on information architecture and technical approaches for data integration efforts such as those in the AISP and NNIP networks and the AISP Learning Community. This guidance will help newly emerging efforts as well as established ones looking to update their current approach. It will also inform policymakers and researchers who need a primer to better understand the technical components and considerations at play for data sharing and integration. This presentation will present findings, best practices and recommendations from this brief that will be released in Fall 2018

“Why archive?” and Other Important Questions Asked by Occupiers

As the Occupy Wall Street (OWS) movement began to take shape in Zuccotti Park—also known as Liberty Square—in New York City, an archives working group formed as a collective interested in preserving the physical and digital documents created by activists in the movement. Members of the Archives Working Group (AWG) were faced with a unique set of challenges, as well as the opportunity to address these challenges in an independent, non-hierarchical, non-institutional setting. Consensus-based decision-making drove the actions of the group, but competing visions also needed to be reconciled. Some of the most common questions about the role and function of archives required explanation, both within and beyond the working group. The desire and need to interact with the archives’ creators was integral to the establishment of the OWS AWG's collection. Managing relationships with any set of living donors is inherently complicated, and the occupiers we found ourselves working with represented a dynamic group of content creators and contributors. Activists ask a lot of questions. By definition activists are challenging the status quo. As members of the AWG, we were asked a lot of very valid questions including: “What is an archive? Is there a difference between art and archives?” “What are you collecting?” “Who will have access to what you are collecting?” “Where is this stuff going to be kept?” “Are you trying to collect all the archives produced in the movement?” “Why collect this?” and “Why not this?” “What do archivists do and why?” “Why should archives matter to people in the movement?” These questions and how we answered them serve as the foundation for this chapter. We will elaborate on our answers to activists’ questions and put forth an analysis of archival theory as related to some of the questions with especially complex implications. The formation of a digital archive also brought up some issues that are beyond those most relevant to the discussion of management of and access to analog archives. Part of this essay is dedicated to the ways in which we addressed these particular concerns. We will conclude with lessons learned in the process of creating a collection of physical and digital archives coming out of Occupy Wall Street in 2011-2012

Vitamin D in obesity

Purpose of review: Vitamin D is essential for bone health, and may also have important functions in immunity and other systems. Vitamin D deficiency is common, and testing and supplementation is increasing. Serum vitamin D is lower in obese people; it is important to understand the mechanism of this effect and whether it indicates clinically significant deficiency. Recent findings: Vitamin D is fat soluble, and distributed into fat, muscle, liver, and serum. All of these compartments are increased in volume in obesity, so the lower vitamin D likely reflects a volumetric dilution effect and whole body stores of vitamin D may be adequate. Despite lower serum vitamin D, obese adults do not have higher bone turnover or lower bone mineral density. Patients undergoing bariatric surgery do have bone loss, and ensuring vitamin D sufficiency in these patients may help to attenuate bone loss. Summary: Lower vitamin D in obese people is a consistent finding across age, ethnicity, and geography. This may not always reflect a clinical problem. Obese people need higher loading doses of vitamin D to achieve the same serum 25-hydroxyvitamin D as normal weight

Independent Origins of New Sex-Linked Chromosomes in the melanica and robusta Species Groups of Drosophila

<p>Abstract</p> <p>Background</p> <p>Recent translocations of autosomal regions to the sex chromosomes represent important systems for identifying the evolutionary forces affecting convergent patterns of sex-chromosome heteromorphism. Additions to the sex chromosomes have been reported in the <it>melanica </it>and <it>robusta </it>species groups, two sister clades of <it>Drosophila</it>. The close relationship between these two species groups and the similarity of their rearranged karyotypes motivates this test of alternative hypotheses; the rearranged sex chromosomes in both groups are derived through a common origin, or the rearrangements are derived through at least two independent origins. Here we examine chromosomal arrangement in representatives of the <it>melanica </it>and the <it>robusta </it>species groups and test these alternative hypotheses using a phylogenetic approach.</p> <p>Results</p> <p>Two mitochondrial and two nuclear gene sequences were used to reconstruct phylogenetic relationships of a set of nine ingroup species having fused and unfused sex chromosomes and representing a broad sample of both species groups. Different methods of phylogenetic inference, coupled with concurrent cytogenetic analysis, indicate that the hypothesis of independent origins of rearranged sex chromosomes within each species group is significantly more likely than the alternative hypothesis of a single common origin. An estimate tightly constrained around 8 My was obtained for the age of the rearranged sex chromosomes in the <it>melanica </it>group; however, a more loosely constrained estimate of 10–15 My was obtained for the age of the rearrangement in the <it>robusta </it>group.</p> <p>Conclusion</p> <p>Independent acquisition of new chromosomal arms by the sex chromosomes in the <it>melanica </it>and <it>robusta </it>species groups represents a case of striking convergence at the karyotypic level. Our findings indicate that the parallel divergence experienced by newly sex-linked genomic regions in these groups represents an excellent system for studying the tempo of sex chromosome evolution.</p