852 research outputs found
Spectroscopic binaries with elliptical orbits
The radial velocity curves of many spectroscopic binaries (SBs) are perturbed
by gas streams or proximity effects. For SBs with circular orbits, these
perturbations can give rise to spurious orbital eccentricities of high
statistical significance. But tests to identify such anomalous orbits can be
constructed since perturbed velocity curves are in general no longer Keplerian.
The derived tests are applied both to synthetic and to observed velocity
curves.Comment: 9pages,3figures,accepted by A&
The Development of Novel Social Cognitive Test in Frontotemporal Dementia
Frontotemporal dementia (FTD) is the second most common cause of early onset dementia in individuals under the age of 65, and in around one third of cases there is a known genetic cause: mutations in chromosome 9 open reading frame 72 (C9orf72), progranulin (GRN) or microtubule-associated tau (MAPT). Language and behaviour are severely affected over the course of the disease, which consequently leads to the breakdown of social relationships. There are a number of problems with the current measures of social cognition, and the focus is mainly on symptomatic individuals, therefore missing those at-risk of FTD. Consequently, it is important to assess these tests in the at-risk cohort as we move towards therapeutic trials, and to also develop novel, more specific, and sensitive tasks. This thesis aims to address these issues using the current standardised tests, and modifying them into eye-tracking equivalents. The results highlight that the current measures are able to detect early social change, but only in individuals carrying a C9orf72 mutation who are within five years to their estimated onset. Two of the novel social cognitive tests showed promise as symptomatic individuals with FTD were able to complete them, but to a lesser extent than controls. Performance was not due to oculomotor deficits. An anti-saccade test also displayed deficits in executive function in symptomatic individuals compared to controls. When these eye-tracking tasks were trialled in an at-risk cohort, the anti-saccade test displayed decreased performance in the C9orf72 presymptomatic carriers compared to non-carriers; no differences were observed on the social cognitive tests. Consequently, this thesis demonstrates the need for new, more sensitive and specific tests for both symptomatic and presymptomatic individuals with FTD. This work highlights the need for careful test design, but it is clear that some tests are able to identify very early presymptomatic change in FTD
Teaching the Holocaust in History: Policy and Classroom Perspectives
This thesis presents an examination of the position of the Holocaust in the National Curriculum for History and of history teachers' interpretation and presentation of this topic. The Interim Report of the History Working Group, which was set up in 1989 to advise the Secretary of State for Education on the form the History Curriculum should take, did not recommend the Holocaust - or the Second World War – as topics for study. This decision was reversed and the Holocaust was included, as an aspect of World War two, in the Group's Final Report. Drawing on a series of interviews with members of the History Working Group, and analysis of their working documentation, this thesis examines and explains this apparent 'u-turn'. Subsequent amendments and revisions to the National Curriculum for History which have resulted in the increasing prominence of the Holocaust, currently one of only four named historical events which must be taught, are set out. In examining the position of the Holocaust in the National Curriculum two key debates are considered: the role of school history and the uniqueness of the Holocaust. There are a number of issues involved in teaching the Holocaust in history which go beyond the usual considerations of lesson planning and resourcing: it would appear the key issue is that teachers are unclear about whether the rationale behind the inclusion of the Holocaust on the History National Curriculum is primarily historical, social or moral. In order to get closer to an answer to this problem this thesis brings together two foci: the history of the Holocaust as a National Curriculum topic and the presentation of this topic in the history classroom. Interviews with teachers of history are drawn upon in addressing the latter strand. It becomes evident that there was a lack of clarity among those who shaped the National Curriculum for History regarding the aims and objectives of including the topic of the Holocaust. This thesis argues that this lack of clarity at the Centre is reflected in the many and varied approaches to teaching the Holocaust found in the history classroom
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Life and (love) letters: looking in on Winckelmann's correspondence
Over the 250 years since his death, Winckelmann’s posthumously published ’private’ correspondence has shaped understandings of his life and work just as much as his aesthetic and antiquarian writings. While editions appeared as early as the 1770s, the publication of Goethe’s Winkelmann und sein Jahrhundert and the inclusion of two volumes of ’freundschaftliche Briefe’ within Josef Eiselein’s Sämtliche Werke (1825-) marked a new role for the correspondence in the nineteenth-century monumentalising of Winckelmann as a German ’classic’. We suggest that this tradition has generated a distanced, even voyeuristic, perspective on the letters, treating them as windows onto biographical scenes of emotional, and sometimes erotic, intimacy and expression. We criticise some examples of this tendency in recent Winckelmann scholarship, explore the often adventitious steps by which it arose, and, using examples of particular letters, suggest some alternative interpretations
Theoretical and Empirical Investigation of Fourier Trajectory Analysis for System Discrimination
With few exceptions, simulation output analysis has focused on static characterizations, to determine a property of the steady-state distribution of a performance metric such as a mean, a quantile, or the distribution itself. Analyses often seek to overcome difficulties induced by autocorrelation of the output stream. But sample paths generated by stochastic simulation exhibit dynamic behavior that is characteristic of system structure and associated distributions. In this technical report, we investigate these dynamic characteristics, as captured by the Fourier transform of a dynamic simulation trajectory. We find that Fourier coefficient magnitudes can have greater discriminatory power than the usual test statistics, and with simpler analysis resulting from the statistical independence of coefficient estimates at different frequencies. Theoretical and Empirical results are provided
Defining the presymptomatic phase of frontotemporal dementia
PURPOSE OF REVIEW: Frontotemporal dementia (FTD) is a clinically, pathologically and genetically heterogeneous disorder. Whilst disease modifying therapies trials are mostly focused on the symptomatic phase, future studies will move earlier in the disease aiming to prevent symptom onset. This review summarizes the recent work to better understand this presymptomatic period. RECENT FINDINGS: The presymptomatic phase can be split into preclinical and prodromal stages. The onset of the preclinical phase is defined by the first presence of pathological inclusions of tau, TDP-43 or fused in sarcoma in the brain. Definitive biomarkers of these pathologies do not yet exist for FTD. The prodromal phase is defined by the onset of mild symptoms. Recent work has highlighted the wide phenotypic spectrum that occurs, with the concept of mild cognitive ± behavioural ± motor impairment (MCBMI) being put forward, and additions to scales such as the CDR plus NACC FTLD now incorporating neuropsychiatric and motor symptoms. SUMMARY: It will be important to better characterize the presymptomatic period moving forward and develop robust biomarkers that can be used both for stratification and outcome measures in prevention trials. The work of the FTD Prevention Initiative aims to facilitate this by bringing together data from natural history studies across the world
A New Measuring Rod: A Qualitative Evaluation of How Slavery is Taught in North Carolina
Slavery created a foundation of profound racial inequality in America, and the philosophy of white supremacy used to justify slavery remains today. Meanwhile, the public education system reaches nearly all young people in our country and is a major force of national socialization: schools instill knowledge in and shape historical consensus of burgeoning citizens. But existing scholarship has established that students in America’s schools incorrectly learned about slavery for over a century (Washburn, 1997). The historical inconsistency requires an evaluation of how social studies educators teach about slavery in 2020. This thesis explores the following research question: how is slavery taught in North Carolina public schools?
The thesis includes a historical contextualization of North Carolina’s public education system to preface the contemporary research analysis. One analytical lens focuses on the current K-12 social studies standards established by the North Carolina Department of Public Instruction (DPI) due to their statewide uniformity, but the research also discerns how educators teach about slavery at a classroom level. Qualitative methods were used to collect input from nearly 70 educators through online surveys and in-person interviews. After synthesizing the main findings, the conclusion features a set of policy recommendations for improved instruction about slavery through a comprehensive three-pronged approach: state-wide, district, and individual teacher levels. Overall, the research underscores how education stakeholders should set a new measuring rod to comprehensively teach the history of slavery by (1) establishing better content expectations, (2) providing more professional learning opportunities about history and race for educators, and (3) blending history and literature courses into humanities offerings.Bachelor of Art
Associations between sport and screen-entertainment with mental health problems in 5-year-old children
<p>Abstract</p> <p>Background</p> <p>Few studies have examined the benefits of regular physical activity, and risks of sedentary behaviour, in young children. This study investigated associations between participation in sports and screen-entertainment (as components of physical activity and sedentary behaviour), and emotional and behavioural problems in this population.</p> <p>Methods</p> <p>Cross-sectional analysis of data from 13470 children (50.9% boys) participating in the nationally representative UK Millennium Cohort Study. Time spent participating in sports clubs outside of school, and using screen-entertainment, was reported by the child's mother at child age 5 years, when mental health was also measured using the Strengths and Difficulties Questionnaire.</p> <p>Results</p> <p>45% of children did not participate in sport clubs and 61% used screen-entertainment for ≥ 2 hours per day. Children who participated in sport had fewer total difficulties; emotional, conduct, hyperactivity-inattention and peer relationship problems; and more prosocial behaviours. These relationships were similar in boys and girls. Boys and girls who used screen-entertainment for any duration, and participated in sport, had fewer emotional and behavioural problems, and more prosocial behaviours, than children who used screen-entertainment for ≥ 2 hours per day and did not participate in sport.</p> <p>Conclusions</p> <p>Longer durations of screen-entertainment usage are not associated with mental health problems in young children. However, our findings suggest an association between sport and better mental health. Further research based on longitudinal data is required to examine causal pathways in these associations and to determine the potential role of this and other forms of physical activity in preventing mental health disorders.</p
Spurious Eccentricities of Distorted Binary Components
I discuss the effect of physical distortion on the velocities of close binary
components and how we may use the resulting distortion of velocity curves to
constrain some properties of binary systems, such as inclination and mass
ratio. Precise new velocities for 5 Cet convincingly detect these distortions
with their theoretically predicted phase dependence. We can even use such
distortions of velocity curves to test Lucy's theory of convective gravity
darkening. The observed distortions for TT Hya and 5 Cet require the contact
components of those systems to be gravity darkened, probably somewhat more than
predicted by Lucy's theory but clearly not as much as expected for a radiative
star. These results imply there is no credible evidence for eccentric orbits in
binaries with contact components. I also present some speculative analyses of
the observed properties of a binary encased in a non-rotating common envelope,
if such an object could actually exist, and discuss how the limb darkening of
some recently calculated model atmospheres for giant stars may bias my resuts
for velocity-curve distortions, as well as other results from a wide range of
analyses of binary stars.Comment: 14 pp, 2 tables, 12 fig; under review by Ap
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