706 research outputs found
Estimating the weak-lensing rotation signal in radio cosmic shear surveys
Weak lensing has become an increasingly important tool in cosmology and the
use of galaxy shapes to measure cosmic shear has become routine. The
weak-lensing distortion tensor contains two other effects in addition to the
two components of shear: the convergence and rotation. The rotation mode is not
measurable using the standard cosmic shear estimators based on galaxy shapes,
as there is no information on the original shapes of the images before they
were lensed. Due to this, no estimator has been proposed for the rotation mode
in cosmological weak-lensing surveys, and the rotation mode has never been
constrained. Here, we derive an estimator for this quantity, which is based on
the use of radio polarisation measurements of the intrinsic position angles of
galaxies. The rotation mode can be sourced by physics beyond CDM, and
also offers the chance to perform consistency checks of CDM and of
weak-lensing surveys themselves. We present simulations of this estimator and
show that, for the pedagogical example of cosmic string spectra, this estimator
could detect a signal that is consistent with the constraints from Planck. We
examine the connection between the rotation mode and the shear -modes and
thus how this estimator could help control systematics in future radio
weak-lensing surveys
The Experience of Aboriginal and Torres Strait Islander Participants in Australia’s Coronial Inquest System: Reflections from the Front Line
This article explains the way that Australian coroners’ courts often fail Aboriginal and Torres Strait Islander peoples. We discuss the gap between the expectations of families of the deceased and the realities of the process of the coroner’s court. The discussion is illustrated with reference to real-life examples, drawn from the authors’ experiences representing the families of the deceased
Time-Restricted Feeding Improves Circadian Dysfunction as well as Motor Symptoms in the Q175 Mouse Model of Huntington's Disease.
Huntington's disease (HD) patients suffer from a progressive neurodegeneration that results in cognitive, psychiatric, cardiovascular, and motor dysfunction. Disturbances in sleep/wake cycles are common among HD patients with reports of delayed sleep onset, frequent bedtime awakenings, and fatigue during the day. The heterozygous Q175 mouse model of HD has been shown to phenocopy many HD core symptoms including circadian dysfunctions. Because circadian dysfunction manifests early in the disease in both patients and mouse models, we sought to determine if early intervention that improve circadian rhythmicity can benefit HD and delay disease progression. We determined the effects of time-restricted feeding (TRF) on the Q175 mouse model. At six months of age, the animals were divided into two groups: ad libitum (ad lib) and TRF. The TRF-treated Q175 mice were exposed to a 6-h feeding/18-h fasting regimen that was designed to be aligned with the middle of the time when mice are normally active. After three months of treatment (when mice reached the early disease stage), the TRF-treated Q175 mice showed improvements in their locomotor activity rhythm and sleep awakening time. Furthermore, we found improved heart rate variability (HRV), suggesting that their autonomic nervous system dysfunction was improved. Importantly, treated Q175 mice exhibited improved motor performance compared to untreated Q175 controls, and the motor improvements were correlated with improved circadian output. Finally, we found that the expression of several HD-relevant markers was restored to WT levels in the striatum of the treated mice using NanoString gene expression assays
A study of information behaviour in the Fantasy Premier League community
Introduction Using Stebbins’ concept of ‘serious leisure’ and Savolainen’s concept of everyday life information seeking’, this study investigates the information behaviour of Fantasy Premier League players and explores the role the online fan community plays in this behaviour. Method A mixed method approach was taken which included a questionnaire and semi structured interviews. 115 questionnaire responses were collected, and 8 interviews were conducted by videocall. Participants were asked to describe their information practices and the sources they used each week. Analysis Qualitative analysis was conducted on the interview transcripts and triangulation occurred with the results of the questionnaire. Results Results show a preference for distinctive information behaviours, a preference for informal sources and differences between casual players and those active in the online community. The role of Twitter in the information behaviour of players was notable. Conclusions The study shows that players use exhibit distinctive and sophisticated information behaviours and that online communities are increasingly important sites of information in serious leisure contexts
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The Effect of Cicadian Therapies in Models of Neurodegenerative Disease
Huntington’s Disease (HD) is an autosomal dominant disorder caused by excessive CAG repeats in the gene encoding the huntingtin protein which leads to progressive neurodegeneration that inflicts cognitive, psychiatric, cardiovascular and motor dysfunction. There is currently no treatment to prevent or delay the course of the disease. Neuronal loss in the striatum is thought to be responsible for the abnormal motor control present in HD patients, though the pathophysiology behind the non-motor symptoms is still unclear. Disturbances in sleep-wake cycles are common among HD patients with reports of delayed sleep onset, frequent bedtime awakenings, and excessive fatigue, and these disruptions are recapitulated in mouse models. Because circadian dysfunction manifests early in the disease in both patients and mouse models, we sought to determine if early interventions that improve circadian rhythmicity could benefit HD symptoms and delay disease progression. Evidence of altered histaminergic signaling in HD patients suggests that this pathway may contribute to disrupted rhythms in arousal. Utilizing the Q175 mouse model of HD, we demonstrated that nightly treatment with a histamine-3 receptor antagonist/inverse agonist improved several behavioral measures of HD including strengthening activity rhythms, cognitive performance, and mood, as well as reducing inappropriate activity during the normal sleep time. Our findings suggest that drugs targeting the histamine-3 receptor system may be beneficial as cognitive enhancers in the management of HD.One of the most powerful regulators of the circadian system is the daily feed/fast cycle, and in two separate studies we found that three months of time-restricted feeding (6-hours of feeding in the middle of the active phase followed by 18-hours fasting) improved the sleep/wake cycle, motor symptoms, and autonomic function in both the Q175 and BACHD mouse models.Finally, we sought to determine whether a ketogenic diet was sufficient to impart motor performance and sleep/wake rhythm benefits in BACHD mice similar to those observed under TRF. We found that the ketogenic diet improves circadian dysfunction as well as motor symptoms in the BACHD mouse model.Altogether, these studies support the hypothesis that early interventions that improve sleep/wake timing and circadian rhythmicity can ameliorate a range of symptoms of HD and related neurodegenerative disorders
Vortex Dynamics and Hall Conductivity of Hard Core Bosons
Magneto-transport of hard core bosons (HCB) is studied using an XXZ quantum
spin model representation, appropriately gauged on the torus to allow for an
external magnetic field. We find strong lattice effects near half filling. An
effective quantum mechanical description of the vortex degrees of freedom is
derived. Using semiclassical and numerical analysis we compute the vortex
hopping energy, which at half filling is close to magnitude of the boson
hopping energy. The critical quantum melting density of the vortex lattice is
estimated at 6.5x10-5 vortices per unit cell. The Hall conductance is computed
from the Chern numbers of the low energy eigenstates. At zero temperature, it
reverses sign abruptly at half filling. At precisely half filling, all
eigenstates are doubly degenerate for any odd number of flux quanta. We prove
the exact degeneracies on the torus by constructing an SU(2) algebra of
point-group symmetries, associated with the center of vorticity. This result is
interpreted as if each vortex carries an internal spin-half degree of freedom
('vspin'), which can manifest itself as a charge density modulation in its
core. Our findings suggest interesting experimental implications for vortex
motion of cold atoms in optical lattices, and magnet-transport of short
coherence length superconductors.Comment: 15 pages, 15 figure
Modelling of Innovative SANEX Process Maloperations
The innovative (i-) SANEX process for the separation of minor actinides from PUREX highly active raffinate is expected to employ a solvent phase comprising 0.2M TODGA with 5 v/v% 1-octanol in an inert diluent. An initial extract / scrub section would be used to extract trivalent actinides and lanthanides from the feed whilst leaving other fission products in the aqueous phase, before the loaded solvent is contacted with a low acidity aqueous phase containing a sulphonated bis-triazinyl pyridine ligand (BTP) to effect a selective strip of the actinides, so yielding separate actinide (An) and lanthanide (Ln) product streams. This process has been demonstrated in lab scale trials at Jülich (FZJ).
The SACSESS (Safety of ACtinide SEparation proceSSes) project is focused on the evaluation and improvement of the safety of such future systems. A key element of this is the development of an understanding of the response of a process to maloperations. It is only practical to study a small subset of possible maloperations experimentally and consideration of the majority of maloperations entails the use of a validated dynamic model of the process.
Distribution algorithms for HNO3, Am, Cm and the lanthanides have been developed and incorporated into a dynamic flowsheet model that has, so far, been configured to correspond to the extract-scrub section of the i-SANEX flowsheet trial undertaken at FZJ in 20131. Comparison is made between the steady state model results and experimental results. Results from modelling of low acidity and high temperature maloperations are presented
Evaluation of Provider-level TEF 2016-17 (Year 2) : measuring the initial impact of the TEF on the higher education landscape
Non-Trivial Vacua in Higher-Derivative Gravitation
A discussion of an extended class of higher-derivative classical theories of
gravity is presented. A procedure is given for exhibiting the new propagating
degrees of freedom, at the full non-linear level, by transforming the
higher-derivative action to a canonical second-order form. For general
fourth-order theories, described by actions which are general functions of the
scalar curvature, the Ricci tensor and the full Riemann tensor, it is shown
that the higher-derivative theories may have multiple stable vacua. The vacua
are shown to be, in general, non-trivial, corresponding to deSitter or
anti-deSitter solutions of the original theory. It is also shown that around
any vacuum the elementary excitations remain the massless graviton, a massive
scalar field and a massive ghost-like spin-two field. The analysis is extended
to actions which are arbitrary functions of terms of the form ,
and it is shown that such theories also have a non-trivial vacuum structure.Comment: 25 pages, LaTeX2e with AMS-LaTeX 1.2, 7 eps figure
The interaction of transmission intensity, mortality, and the economy: a retrospective analysis of the COVID-19 pandemic
The COVID-19 pandemic has caused over 6.4 million registered deaths to date,
and has had a profound impact on economic activity. Here, we study the
interaction of transmission, mortality, and the economy during the SARS-CoV-2
pandemic from January 2020 to December 2022 across 25 European countries. We
adopt a Bayesian vector autoregressive model with both fixed and random
effects. We find that increases in disease transmission intensity decreases
Gross domestic product (GDP) and increases daily excess deaths, with a longer
lasting impact on excess deaths in comparison to GDP, which recovers more
rapidly. Broadly, our results reinforce the intuitive phenomenon that
significant economic activity arises from diverse person-to-person
interactions. We report on the effectiveness of non-pharmaceutical
interventions (NPIs) on transmission intensity, excess deaths and changes in
GDP, and resulting implications for policy makers. Our results highlight a
complex cost-benefit trade off from individual NPIs. For example, banning
international travel increases GDP however reduces excess deaths. We consider
country random effects and their associations with excess changes in GDP and
excess deaths. For example, more developed countries in Europe typically had
more cautious approaches to the COVID-19 pandemic, prioritising healthcare and
excess deaths over economic performance. Long term economic impairments are not
fully captured by our model, as well as long term disease effects (Long Covid).
Our results highlight that the impact of disease on a country is complex and
multifaceted, and simple heuristic conclusions to extract the best outcome from
the economy and disease burden are challenging
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