712 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
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
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
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Circadian modulation by time-restricted feeding rescues brain pathology and improves memory in mouse models of Alzheimer’s disease
Circadian disruptions impact nearly all people with Alzheimer's disease (AD), emphasizing both their potential role in pathology and the critical need to investigate the therapeutic potential of circadian-modulating interventions. Here, we show that time-restricted feeding (TRF) without caloric restriction improved key disease components including behavioral timing, disease pathology, hippocampal transcription, and memory in two transgenic (TG) mouse models of AD. We found that TRF had the remarkable capability of simultaneously reducing amyloid deposition, increasing Aβ42 clearance, improving sleep and memory, and normalizing daily transcription patterns of multiple genes, including those associated with AD and neuroinflammation. Thus, our study unveils for the first time the pleiotropic nature of timed feeding on AD, which has far-reaching effects beyond metabolism, ameliorating neurodegeneration and the misalignment of circadian rhythmicity. Since TRF can substantially modify disease trajectory, this intervention has immediate translational potential, addressing the urgent demand for accessible approaches to reduce or halt AD progression
KK-duality for self-similar groupoid actions on graphs
We extend Nekrashevych's -duality for -algebras of regular,
recurrent, contracting self-similar group actions to regular, contracting
self-similar groupoid actions on a graph, removing the recurrence condition
entirely and generalising from a finite alphabet to a finite graph.
More precisely, given a regular and contracting self-similar groupoid
acting faithfully on a finite directed graph , we associate two
-algebras, and , to it and
prove that they are strongly Morita equivalent to the stable and unstable
Ruelle C*-algebras of a Smale space arising from a Wieler solenoid of the
self-similar limit space. That these algebras are Spanier-Whitehead dual in
-theory follows from the general result for Ruelle algebras of irreducible
Smale spaces proved by Kaminker, Putnam, and the last author.Comment: File updated to make several corrections. Example 8.15 adde
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