The effect of redshift-space distortions on projected 2-pt clustering measurements

Although redshift-space distortions only affect inferred distances and not angles, they still distort the projected angular clustering of galaxy samples selected using redshift dependent quantities. From an Eulerian view-point, this effect is caused by the apparent movement of galaxies into or out of the sample. From a Lagrangian view-point, we find that projecting the redshift-space overdensity field over a finite radial distance does not remove all the anisotropic distortions. We investigate this effect, showing that it strongly boosts the amplitude of clustering for narrow samples and can also reduce the significance of baryonic features in the correlation function. We argue that the effect can be mitigated by binning in apparent galaxy pair-centre rather than galaxy position, and applying an upper limit to the radial galaxy separation. We demonstrate this approach, contrasting against standard top-hat binning in galaxy distance, using sub-samples taken from the Hubble Volume simulations. Using a simple model for the radial distribution expected for galaxies from a survey such as the Dark Energy Survey (DES), we show that this binning scheme will simplify analyses that will measure baryon acoustic oscillations within such galaxy samples. Comparing results from different binning schemes has the potential to provide measurements of the amplitude of the redshift-space distortions. Our analysis is relevant for other photometric redshift surveys, including those made by the Panoramic Survey Telescope & Rapid Response System (Pan-Starrs) and the Large Synoptic Survey Telescope (LSST).Comment: 13 pages, 15 figures, accepted by MNRAS, corrected typos, revised argument in section 3, figure added in section 3, results unchange

Participation and representation in ATSIC elections: a ten-year perspective

This paper examines participation and representation in Aboriginal and Torres Strait Islander Commission (ATSIC) elections over the ten-year period since its inception in 1990. It attempts to identify patterns of participation that seem to be emerging and what these might suggest about ATSIC's operation. By examining numbers of nominees compared to positions available, the paper suggests that ATSIC elected office has fairly keenly and consistently sought and competed for by Indigenous people, though there may have been some slight initial reticence in the 1990 elections. By examining voter numbers and voter turnout, the paper suggests that voter participation nation-wide rose slightly from 1990 to 1996 and then largely stabilised in 1999. It also suggests that there have been significant variations from this national pattern at State and Territory levels and it explores some reasons for this, such as change in postal voting procedures. The paper also examines voter numbers and voter turnout at the ATSIC regional level since 1993 and finds that there has been a much higher voter turnout in the sparsely settled regions of northern Australia and much lower voter turnout in the southern and urban areas. This is explained in terms of ATSIC program and expenditure priorities and in terms of polling place access. The final two sections of the paper examine the representation of women and Torres Strait Islanders among ATSIC elected representatives. Both are seen as significant issues, which should be of some ongoing concern within ATSIC, alongside the issue of the southern/northern difference in voter participation

The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15

We create a sample of spectroscopically identified galaxies with $z < 0.2$ from the Sloan Digital Sky Survey (SDSS) Data Release 7, covering 6813 deg$^2$. Galaxies are chosen to sample the highest mass haloes, with an effective bias of 1.5, allowing us to construct 1000 mock galaxy catalogs (described in Paper II), which we use to estimate statistical errors and test our methods. We use an estimate of the gravitational potential to "reconstruct" the linear density fluctuations, enhancing the Baryon Acoustic Oscillation (BAO) signal in the measured correlation function and power spectrum. Fitting to these measurements, we determine $D_{V}(z_{\rm eff}=0.15) = (664\pm25)(r_d/r_{d,{\rm fid}})$ Mpc; this is a better than 4 per cent distance measurement. This "fills the gap" in BAO distance ladder between previously measured local and higher redshift measurements, and affords significant improvement in constraining the properties of dark energy. Combining our measurement with other BAO measurements from BOSS and 6dFGS galaxy samples provides a 15 per cent improvement in the determination of the equation of state of dark energy and the value of the Hubble parameter at $z=0$ ($H_0$). Our measurement is fully consistent with the Planck results and the $\Lambda$CDM concordance cosmology, but increases the tension between Planck$+$BAO $H_0$ determinations and direct $H_0$ measurements.Comment: Accepted by MNRAS, distance likelihood is available in source file

Urban health and the history of public hospitals in the U.S.

Poster for the 44th Historia Medica lecture.https://digitalcommons.wustl.edu/historyofmedicine_historia_medica_posters/1000/thumbnail.jp

After the Rain – learning the lessons from flood recovery in Hull

The report shows that it is often not so much the floods themselves, but what comes afterwards, that people find so difficult to deal with. The research on which this report is based aimed to undertake a real-time longitudinal study to document and understand the everyday experiences of individuals following the floods of June 2007 in interaction with networks of actors and organisations, strategies of institutional support and investment in the built environment and infrastructure. It had the following objectives: - To identify and document key dimensions of the longer term experience of flood impact and flood recovery, including health, economic and social aspects. - To examine how resilience and vulnerability were manifest in the interaction between everyday strategies of adaptation during the flood recovery process, and modes of institutional support and the management of infrastructure and the built environment. -To explore to what extent the recovery process entailed the development of new forms of resilience and to identify the implications for developing local level resilience for flood recovery in the future. To develop an archive that will be accessible for future research into other aspects of flood recovery. The flooding which affected the city of Kingston-upon-Hull took place in June 2007. Over 110mm of rain fell during the biggest event, overwhelming the city‟s drainage system and resulting in widespread pluvial flooding. The floods affected over 8,600 households and one person was killed. Our research used in-depth, qualitative methods where 44 people kept weekly diaries and participated in interviews and group discussions over an 18-month period

Improved primordial non-gaussianity constraints from measurements of galaxy clustering and the integrated Sachs-Wolfe effect

We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cross-correlations with the cosmic microwave background. We update the data sets used by Giannantonio et al. (2012), and broaden that analysis to include the full set of two-point correlation functions between all surveys. In order to obtain the most reliable constraints on PNG, we advocate the use of the cross-correlations between the catalogs as a robust estimator and we perform an extended analysis of the possible systematics to reduce their impact on the results. To minimize the impact of stellar contamination in our luminous red galaxy (LRG) sample, we use the recent Baryon Oscillations Spectroscopic Survey catalog of Ross et al. (2011). We also find evidence for a new systematic in the NVSS radio galaxy survey similar to, but smaller than, the known declination-dependent issue; this is difficult to remove without affecting the inferred PNG signal, and thus we do not include the NVSS auto-correlation function in our analyses. We find no evidence of primordial non-Gaussianity; for the local-type configuration we obtain for the skewness parameter $-36 < f_{\mathrm{NL}} < 45$ at 95 % c.l. ($5 \pm 21$ at $1\sigma$) when using the most conservative part of our data set, improving previous results; we also find no evidence for significant kurtosis, parameterized by $g_{\mathrm{NL}}$. In addition to PNG, we simultaneously constrain dark energy and find that it is required with a form consistent with a cosmological constant.Comment: 24 pages, 16 figures. More conservative treatment of the NVSS data, version accepted by Phys. Rev.

How Community-Based Solutions Affect Households Headed by Single Mothers in an Urban Food Desert

Limited access to affordable and nutritious foods is a growing problem in the United States, leading to a rise in obesity, diabetes, and heart disease as well as poor academic performance. With this has come the rise of urban food deserts, specific geographic areas with limited access to affordable, healthy, and nutritious foods within a 1-mile radius, which impacts low-income and minority communities at a greater rate than the rest of US society. Single mothers represent the largest demographic impacted by urban food deserts yet are the least represented in research. The purpose of this narrative study, using the human rights framework, was to gain a more in-depth understanding of how urban food deserts impact the lives of single mothers who reside there. Data were collected via a series of open-ended interview questions with 19 participants, who were identified through purposeful sampling. The participants included 12 single mothers, one local community leader, and 6 local food program leaders. The interviews were then transcribed and coded to identify themes using qualitative analysis software. The results confirmed the difficulties single mothers faced accessing food and emphasized the need for services provided by community-based programs. The findings may be used by local community leaders to help formulate partnerships as well as develop additional community-based programs to help alleviate food insecurity. With effective policies and appropriate partnerships, communities can improve the overall health and wellbeing of underserved and inadequately nourished populations, thereby affecting positive social change