The Accuracy of Subhalo Detection

With the ever increasing resolution of N-body simulations, accurate subhalo detection is becoming essential in the study of the formation of structure, the production of merger trees and the seeding of semi-analytic models. To investigate the state of halo finders, we compare two different approaches to detecting subhaloes; the first based on overdensities in a halo and the second being adaptive mesh refinement. A set of stable mock NFW dark matter haloes were produced and a subhalo was placed at different radii within a larger halo. SUBFIND (a Friends-of-Friends based finder) and AHF (an adaptive mesh based finder) were employed to recover the subhalo. As expected, we found that the mass of the subhalo recovered by SUBFIND has a strong dependence on the radial position and that neither halo finder can accurately recover the subhalo when it is very near the centre of the halo. This radial dependence is shown to be related to the subhalo being truncated by the background density of the halo and originates due to the subhalo being defined as an overdensity. If the subhalo size is instead determined using the peak of the circular velocity profile, a much more stable value is recovered. The downside to this is that the maximum circular velocity is a poor measure of stripping and is affected by resolution. For future halo finders to recover all the particles in a subhalo, a search of phase space will need to be introduced.Comment: 9 pages, 7 figures, accepted for publication in MNRA

You\u27re in our world now : sex and gaming styles in massive multiplayer online gaming

A study of communication behaviors in the massive multiplayer online roleplaying game, Everquest™, was conducted to determine if there were any relationships between playing styles, gendered communication strategies, and player or character sex. The use of feminist standpoint theory as a theoretical framework allowed the results of the study to be generalized to the social constructs known as man and woman, without necessarily indicating the results are true for individuals. The study found that it was possible to classify an individual\u27s playing style as either that of a roleplayer or a power-gamer, but that there was not a significant link between these playing styles and communication strategies or the sex of the player or character. There was some evidence that communication strategies are different between the sexes, but the virtual sample observed did not include enough women to allow sufficient analysis of this phenomenon. The gaming environment might have been biased towards men and could have discouraged women from participating

Factors Influencing the Health of Negroes in Houston, Texas

Facts on Negro health are of the greatest interest to workers in the health field for a variety of reasons, Negroes constitute close to one-tenth of the total population of the United States. They are a clear-cut social group with very definite health problems that call for a solution. Health is basic to the general welfare of the Negro as to no other race. An improvement in Negro health, to the point when it would compare favorably with that of the white race, would at one stroke impress many and wipe out numerous disabilities from which the race suffers, improve its economic status, and stimulate its motive abilities, as would no other single improvement. These are the social implications, of the facts concerning Negro health. There have been discussions concerning the casual relationship of economic conditions to death rates. As a result of these discussions, consensus of opinion indicates that poor economic conditions and high death rates are frequently found together. If there is a possibility that economic conditions are an influencing factor in death, it is highly desirable that studies be made to determine the extent of such a relationship along with other factors having a bearing on high death rates. The present study, FACTORS INFLUENCING THE HEALTH OF THE NEGRO IN HOUSTON, takes into consideration the following factors: percentage in the total population of Negroes, number of persons per family, average monthly rental of homes, arrests, delinquencies, syphilis and tuberculosis death rates. Through the consideration of the foregoing topics, a conclusion will be derived as to some of the factors that influence Negro health in Houston, the low economic area with the congested population

Streams Going Notts: The tidal debris finder comparison project

While various codes exist to systematically and robustly find haloes and subhaloes in cosmological simulations (Knebe et al., 2011, Onions et al., 2012), this is the first work to introduce and rigorously test codes that find tidal debris (streams and other unbound substructure) in fully cosmological simulations of structure formation. We use one tracking and three non-tracking codes to identify substructure (bound and unbound) in a Milky Way type simulation from the Aquarius suite (Springel et al., 2008) and post-process their output with a common pipeline to determine the properties of these substructures in a uniform way. By using output from a fully cosmological simulation, we also take a step beyond previous studies of tidal debris that have used simple toy models. We find that both tracking and non-tracking codes agree well on the identification of subhaloes and more importantly, the {\em unbound tidal features} associated with them. The distributions of basic properties of the total substructure distribution (mass, velocity dispersion, position) are recovered with a scatter of $\sim20$. Using the tracking code as our reference, we show that the non-tracking codes identify complex tidal debris with purities of $\sim40$. Analysing the results of the substructure finders, we find that the general distribution of {\em substructures} differ significantly from the distribution of bound {\em subhaloes}. Most importantly, both bound and unbound {\em substructures} together constitute $\sim18$ of the host halo mass, which is a factor of $\sim2$ higher than the fraction in self-bound {\em subhaloes}. However, this result is restricted by the remaining challenge to cleanly define when an unbound structure has become part of the host halo. Nevertheless, the more general substructure distribution provides a more complete picture of a halo's accretion history.Comment: 19 pages, 12 figures, accepted for publication in MNRA

Validation and feasibility of OSOLAS

OSOLAS aims to be a resource that connects students with careers they are passionate about. It is aimed at students aged between 15 - 20 years old that are in the process of making decisions about what career path they should follow. This project focused on identifying the students' biggest frustrations regarding career decisions and validating a potential solution to those issues. A business model was then created to determine how OSOLAS could financially sustain its ongoing growth and development

Examining palliative and end of life care research in Ireland within a global context: a systematic mapping review of the evidence

Background: Globally the state of palliative care research remains uncertain. Questions remain regarding impact, funding, and research priorities. Building upon previous research, this review examines palliative care research in Ireland and contributes to a wider international debate on the state of palliative care research. Methods: A systematic mapping review was undertaken. Eight bibliographic databases and thesis repositories were searched from May 2012 to April 2017. Palliative care related search terms were combined with "Ireland" or "Irish" to increase search sensitivity. Inclusion criteria were applied by two independent reviewers. Descriptive analysis was completed using IBM SPSS v23. Thematic analysis was undertaken using a data-driven approach to develop new themes. Results: In total, 808 studies were screened and 151 papers from 117 studies were included for review. The top two areas of research focus included: (1) specific groups, services, and settings (n = 70); and (2) identification, communication and education (n = 37). A diverse variety of research methods were used including mixed methods (25%), surveys (22%), interviews (20%), and reviews (17%). One randomised control trial was conducted. The predominance of research papers focused solely on health care professionals (n = 35%), and the community setting was the most frequent location for data collection (41%). The majority of data was collected across the two jurisdictions of the Republic of Ireland (ROI) and Northern Ireland (NI) (37%), and 23% of studies included data outside of Ireland and the UK. The most frequent sources of funding were: consortiums (n = 40); government (n = 24); and philanthropic bodies (n = 20). Forty percent (n = 60) of papers were either unfunded or did not acknowledge a funder. Conclusions: There is a continued increase in palliative care research in Ireland with increased collaborative working nationally and internationally. The quantity and impact of research has increased from the previous review, which can be attributed to significant investment in research funding and collaborative networks. However, research gaps continue to exist including out of hours' care, physical and psychological symptom control, intervention studies, and the patient and family perspective. Areas for attention include the need to ensure knowledge exchange and demonstrate impact of the research on patient and family carer outcomes. © 2018 The Author(s)

What are protoclusters? – Defining high-redshift galaxy clusters and protoclusters

We explore the structures of protoclusters and their relationship with high-redshift clusters using the Millennium Simulation combined with a semi-analytic model. We find that protoclusters are very extended, with 90 per cent of their mass spread across∼35 h−1 Mpc commoving at z =2 (∼30 arcmin). The ‘main halo’, which can manifest as a high-redshift cluster or group, is only a minor feature of the protocluster, containing less than 20 per cent of all protocluster galaxies at z = 2. Furthermore, many protoclusters do not contain a main halo that is massive enough to be identified as a high-redshift cluster. Protoclusters exist in a range of evolutionary states at high redshift, independent of the mass they will evolve to at z = 0. We show that the evolutionary state of a protocluster can be approximated by the mass ratio of the first and second most massive haloes within the protocluster, and the z = 0 mass of a protocluster can be estimated to within 0.2 dex accuracy if both the mass of the main halo and the evolutionary state are known. We also investigate the biases introduced by only observing star-forming protocluster members within small fields. The star formation rate required for line-emitting galaxies to be detected is typically high, which leads to the artificial loss of low-mass galaxies from the protocluster sample. This effect is stronger for observations of the centre of the protocluster, where the quenched galaxy fraction is higher. This loss of low-mass galaxies, relative to the field, distorts the size of the galaxy overdensity, which in turn can contribute to errors in predicting the z = 0 evolved mass