A statistical method for measuring the Galactic potential and testing gravity with cold tidal streams

We introduce the Minimum Entropy Method, a simple statistical technique for constraining the Milky Way gravitational potential and simultaneously testing different gravity theories directly from 6D phase-space surveys and without adopting dynamical models. We demonstrate that orbital energy distributions that are separable (i.e. independent of position) have an associated entropy that increases under wrong assumptions about the gravitational potential and/or gravity theory. Of known objects, `cold' tidal streams from low-mass progenitors follow orbital distributions that most nearly satisfy the condition of separability. Although the orbits of tidally stripped stars are perturbed by the progenitor's self-gravity, systematic variations of the energy distribution can be quantified in terms of the cross-entropy of individual tails, giving further sensitivity to theoretical biases in the host potential. The feasibility of using the Minimum Entropy Method to test a wide range of gravity theories is illustrated by evolving restricted N-body models in a Newtonian potential and examining the changes in entropy introduced by Dirac, MONDian and f(R) gravity modifications.Comment: Accepted for publication in ApJ. 11 pages 6 figure

Mindful Leadership and Climate Action

Organizations must get serious about reaching the goals for addressing Climate Action outlined in the United Nations Sustainable Development Goal (SDG)13. The problem to solve is how the leaders who created the climate issues can be the leaders to make climate action happen. The development of mindful leaders within an organization is the answer to the problem. Mindful leaders are developed not only with the Inner Development Goal (IDG) framework which is developed to align and support the 17 SDGs of the United Nations. The development of mindful leaders comes from ancient and modern practices that draw from Buddhism, secular practices, neuroscience, modern psychology, and contemporary leadership research. One great intersection between mindful leaders and climate action is that many traditions across the centuries draw on powerful practices for leaders to be in tune and in touch with personal history and nature in the present moment. Within Europe, the effects of climate change are happening at an ever-increasing rate, and extreme weather events are becoming common. The time for mindful leaders who bring teams together to create the radical innovations required is urgent for climate action to occur

Exploring the Socioeconomic Composition of Wind Farm Communities in Ontario: Implications for Wind Farm Planning and Policy

This research explores the socioeconomic composition of sixteen wind farm communities in Ontario, Canada, for wind farms commissioned between 2006 and 2012. Past research has shown that wind farms are disproportionately developed in socioeconomically disadvantaged areas and that socioeconomic factors influence wind farm support, an important factor in wind farm planning. This research finds that wind farm communities do not exhibit characteristics of disadvantage compared to host counties. Investigating the association between when wind farms were commissioned and community-scale characteristics, this research observes that communities with wind farms operational before 2009 had significantly lower median income compared to communities with wind farms operational after 2009. This provides one perspective on how community-scale characteristics may shape wind farm planning, specifically the influence of local opposition and financial incentives on the location of wind farm developments

Willingness to pay for the control of water hyacinth in an urban environment of South Africa

Water hyacinth is recognised as one of the most problematic invasive aquatic plant species in Africa. For this reason considerable funds are spent each year on itscontrol. As a consequence of the amount of money being spent on problems such as the invasion of water hyacinth, and because of the recognition of the ongoing and accelerated efforts that are required in the future, recent research has focused on accurately quantifying the costs and benefits of control of invasive species to aid policy decisions.A comprehensive cost-benefit analysis would be able to identify if the funds are justified and are being spent effectively. This thesis provides an example of a cost-benefit analysis of funds spent on the control of water hyacinth in an urban environment in South Africa. In order to develop a comprehensive assessment of the total economic value of the control of water hyacinth to an urban population, the Nahoon River in East London was selected as the study site to calculate the benefits of control. In addition to valuing the direct services provided by the resources that are traded in the market (in this case water provision), a contingent valuation study was undertaken in Abbottsford and Dorchester Heights (two suburbs in East London banking the Nahoon River). These were done in order to assess any non-use value a sample of 132 households of the population has for the control of water hyacinth, and any use values that are not traded in the market, for example recreational value. When the benefits of control of water hyacinth were compared to the costs of one of the least cost effective methods of control (herbicidal control), the benefits outweighed the costs by a ratio of more than 4:1, and for the most cost effective method of control the ratio was almost 6:1. These results provide a justification for the funds that are devoted to the control of water hyacinth, providing an argument for the continued expenditure for its control, and for further research into more cost effective methods of control, such as biological control

Occupational Risk Perceptions Among Foreign-Born Construction Workers in Central Florida

Hispanic and Latino foreign-born construction workers in the United States experience higher rates of serious injuries and fatalities in the workplace than their native-born peers. Previous research has pointed to specific vulnerabilities among this population, including birthplace, age of the worker, language barriers, and education level, but little to no research has examined addressable risk factors, such as occupational risk perceptions, among this population. The purpose of this quantitative study was to determine the relationship between birthplace, number of years working in the United States, and occupational risk perceptions while controlling for age of the worker, language barriers, and education level. A modified conceptual model that links specific demographic factors to occupational risk perceptions served as the framework for the study. A convenience sample of construction workers in central Florida provided demographic information and self-reported risk perceptions in this cross-sectional study. Multiple linear regression analyses were used to examine potential relationships between birthplace and risk perceptions as well as number of years working in the United States and risk perceptions. The results of these analyses indicated a statistically significant difference in risk perceptions between foreign-born and native-born construction workers, but time spent working in the United States did not affect these risk perceptions. The implications for positive social change include the identification of risk factors that are addressable through improved training and better communication. Addressing these factors may help reduce injuries and fatalities among Hispanic and Latino foreign-born construction workers in central Florida

Occupational Risk Perceptions Among Foreign-Born Construction Workers in Central Florida

Hispanic and Latino foreign-born construction workers in the United States experience higher rates of serious injuries and fatalities in the workplace than their native-born peers. Previous research has pointed to specific vulnerabilities among this population, including birthplace, age of the worker, language barriers, and education level, but little to no research has examined addressable risk factors, such as occupational risk perceptions, among this population. The purpose of this quantitative study was to determine the relationship between birthplace, number of years working in the United States, and occupational risk perceptions while controlling for age of the worker, language barriers, and education level. A modified conceptual model that links specific demographic factors to occupational risk perceptions served as the framework for the study. A convenience sample of construction workers in central Florida provided demographic information and self-reported risk perceptions in this cross-sectional study. Multiple linear regression analyses were used to examine potential relationships between birthplace and risk perceptions as well as number of years working in the United States and risk perceptions. The results of these analyses indicated a statistically significant difference in risk perceptions between foreign-born and native-born construction workers, but time spent working in the United States did not affect these risk perceptions. The implications for positive social change include the identification of risk factors that are addressable through improved training and better communication. Addressing these factors may help reduce injuries and fatalities among Hispanic and Latino foreign-born construction workers in central Florida

Physical function limitation among gay and bisexual men aged ≥55years with and without HIV: findings from the Australian Positive and Peers Longevity Evaluation Study (APPLES)

Background. As people living with HIV now have a life expectancy approaching that of the general population, clinical care focuses increasingly on the management and prevention of comorbidities and conditions associated with aging. We aimed to assess the prevalence of physical function (PF) limitation among gay and bisexual men (GBM) and determine whether HIV is associated with severe PF limitation in this population. Methods. We analysed cross-sectional data from GBM aged ≥55 years in the Australian Positive and Peers Longevity Evaluation Study who completed a self-administered survey on health and lifestyle factors. PF was measured using the Medical Outcomes Study–Physical Functioning scale. Factors associated with severe PF limitation were assessed using logistic regression. Results. The survey was completed by 381 men: 186 without HIV and 195 with HIV. Median age was 64.3 years for GBM without HIV and 62.1 years for GBM with HIV. Compared with men without HIV, those with HIV had higher proportions of severe (13.3% vs 8.1%) and moderate-to-severe (26.7% vs 24.2%) PF limitation. Severe PF limitation commonly involved difficulty with vigorous activity (95% with severe PF limitation described being limited a lot), climbing several flights of stairs (68.4% limited a lot), bending, kneeling or stooping (60.5% limited a lot), and walking 1 km (55.0% limited a lot). In a model adjusted for age, body mass index, typical duration of physical activity, psychological distress, and number of comorbidities, we found a significant association between HIV and severe PF limitation (adjusted odds ratio 3.3 vs not having HIV, 95% confidence interval 1.3–8.7). Conclusions. The biological mechanisms underlying this association require further investigation, particularly given the growing age of the HIV population and inevitable increase in the burden of PF limitation

Archaeology in the Western Isles: the molluscan evidence

Using assemblages of marine and non-marine mollusc shells from recent excavations in the Western Isles of Scotland, with reference to previously published studies, this thesis contributes to an enhanced understanding of the cultural palaeoecology of insular societies. Chaoter 1 sets out the topics that will be covered in this thesis. Chapter 2 introduces the methods and principles that drive molluscan analysis; Chapter 3 outlines the natural history of the Western Isles; and Chapter 4 the archaeology. Previous work on molluscs from the islands are summarised in Chapter 5, and emergent themes identified. Chapter 6 presents the results of analyses of new non-marine molluscan assemblages from 9 sites, ranging in date from the Mesolithic to the Norse period. Comparative data collected from a transect of samples for modern snails are also presented, along with a statistical meta-analysis of the data. Chapter 7 presents the results of marine shell analyses from 4 sites, ranging in date from the Early Bronze Age to the Norse period. The results are discussed in terms of their regional and wider significance in Chapter 8, and the thesis concluded in Chapter 9. Studying non-marine and marine molluscs from a wide range of sites across the islands has made important contributions to the archaeology of the Western Isles. The movement of new species of snail into and across the islands emphasises the connectedness of prehistoric communities across wider social networks on the Atlantic coast of Europe. The study of non-marine molluscs and the use of statistical analysis contributes to a broader understanding of taphonomy and site formation processes. Combined analysis of marine and non-marine mollusc shells highlights the agricultural practices and land use of prehistoric and Norse farmers. Studies of larger marine shells indicate changing tastes at the time of increasing contact with the Norse diaspora

CAMERA: a compact, automated, laser adaptive optics system for small aperture telescopes

CAMERA is an autonomous laser guide star adaptive optics system designed for small aperture telescopes. This system is intended to be mounted permanently on such a telescope to provide large amounts of flexibly scheduled observing time, delivering high angular resolution imagery in the visible and near infrared. The design employs a Shack Hartmann wavefront sensor, a 12x12 actuator MEMS device for high order wavefront compensation, and a solid state 355nm ND:YAG laser to generate a guide star. Commercial CCD and InGaAs detectors provide coverage in the visible and near infrared. CAMERA operates by selecting targets from a queue populated by users and executing these observations autonomously. This robotic system is targeted towards applications that are diffcult to address using classical observing strategies: surveys of very large target lists, recurrently scheduled observations, and rapid response followup of transient objects. This system has been designed and costed, and a lab testbed has been developed to evaluate key components and validate autonomous operations