Using Cold Atoms to Measure Neutrino Mass

We propose a beta decay experiment based on a sample of ultracold atomic tritium. These initial conditions enable detection of the helium ion in coincidence with the beta. We construct a two-dimensional fit incorporating both the shape of the beta-spectrum and the direct reconstruction of the neutrino mass peak. We present simulation results of the feasible limits on the neutrino mass achievable in this new type of tritium beta-decay experiment.Comment: 10 pages, 5 figure

Single-Photon Molecular Cooling

We propose a general method to cool the translational motion of molecules. Our method is an extension of single photon atomic cooling which was successfully implemented in our laboratory. Requiring a single event of absorption followed by a spontaneous emission, this method circumvents the need for a cycling transition and can be applied to any paramagnetic or polar molecule. In our approach, trapped molecules would be captured near their classical turning points in an optical dipole or RF-trap following an irreversible transition process

Collision statistics in sheared inelastic hard spheres

The dynamics of sheared inelastic-hard-sphere systems are studied using non-equilibrium molecular dynamics simulations and direct simulation Monte Carlo. In the molecular dynamics simulations Lees-Edwards boundary conditions are used to impose the shear. The dimensions of the simulation box are chosen to ensure that the systems are homogeneous and that the shear is applied uniformly. Various system properties are monitored, including the one-particle velocity distribution, granular temperature, stress tensor, collision rates, and time between collisions. The one-particle velocity distribution is found to agree reasonably well with an anisotropic Gaussian distribution, with only a slight overpopulation of the high velocity tails. The velocity distribution is strongly anisotropic, especially at lower densities and lower values of the coefficient of restitution, with the largest variance in the direction of shear. The density dependence of the compressibility factor of the sheared inelastic hard sphere system is quite similar to that of elastic hard sphere fluids. As the systems become more inelastic, the glancing collisions begin to dominate more direct, head-on collisions. Examination of the distribution of the time between collisions indicates that the collisions experienced by the particles are strongly correlated in the highly inelastic systems. A comparison of the simulation data is made with DSMC simulation of the Enskog equation. Results of the kinetic model of Montanero et al. {[}Montanero et al., J. Fluid Mech. 389, 391 (1999){]} based on the Enskog equation are also included. In general, good agreement is found for high density, weakly inelastic systems.Comment: 10 figures, 1 table, 27 page

Impulsive choice in hippocampal but not orbitofrontal cortex-lesioned rats on a nonspatial decision-making maze task

Orbitofrontal cortical (OFC) and hippocampal (HPC) lesions in primates and rodents have been associated with impulsive behaviour. We showed previously that OFC- or HPC-lesioned rats chose the immediate low-reward (LR) option in preference to the delayed high-reward (HR) option, where LR and HR were associated with different spatial responses in a uniform grey T-maze. We now report that on a novel nonspatial T-maze task in which the HR and LR options are associated with patterned goal arms (black-and-white stripes vs. gray), OFC-lesioned rats did not show impulsive behaviour, choosing the delayed HR option, and were indistinguishable from controls. In contrast, HPC-lesioned rats exhibited impulsive choice in the nonspatial decision-making task, although they chose the HR option on the majority of trials when there was a 10-s delay associated with both goal arms. The previously reported impairment in OFC-lesioned rats on the spatial version of the intertemporal choice task is unlikely to reflect a general problem with spatial learning, because OFC lesions were without effect on acquisition of the standard reference memory water-maze task and spatial working memory performance (nonmatching-to-place) on the T-maze. The differential effect of OFC lesions on the two versions of the intertemporal choice task may be explained instead in terms of the putative role of OFC in using associative information to represent expected outcomes and generate predictions. The impulsivity in HPC-lesioned rats may reflect impaired temporal information processing, and emphasizes a role for the hippocampus beyond the spatial domain

Deletion of AMPA receptor GluA1 subunit gene (Gria1) causes circadian rhythm disruption and aberrant responses to environmental cues

Dysfunction of the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluA1 subunit and deficits in synaptic plasticity are implicated in schizophrenia and sleep and circadian rhythm disruption. To investigate the role of GluA1 in circadian and sleep behaviour, we used wheel-running, passive-infrared, and video-based home-cage activity monitoring to assess daily rest–activity profiles of GluA1-knockout mice (Gria1−/−). We showed that these mice displayed various circadian abnormalities, including misaligned, fragmented, and more variable rest–activity patterns. In addition, they showed heightened, but transient, behavioural arousal to light→dark and dark→light transitions, as well as attenuated nocturnal-light-induced activity suppression (negative masking). In the hypothalamic suprachiasmatic nuclei (SCN), nocturnal-light-induced cFos signals (a molecular marker of neuronal activity in the preceding ~1–2 h) were attenuated, indicating reduced light sensitivity in the SCN. However, there was no change in the neuroanatomical distribution of expression levels of two neuropeptides―vasoactive intestinal peptide (VIP) and arginine vasopressin (AVP)―differentially expressed in the core (ventromedial) vs. shell (dorsolateral) SCN subregions and both are known to be important for neuronal synchronisation within the SCN and circadian rhythmicity. In the motor cortex (area M1/M2), there was increased inter-individual variability in cFos levels during the evening period, mirroring the increased inter-individual variability in locomotor activity under nocturnal light. Finally, in the spontaneous odour recognition task GluA1 knockouts’ short-term memory was impaired due to enhanced attention to the recently encountered familiar odour. These abnormalities due to altered AMPA-receptor-mediated signalling resemble and may contribute to sleep and circadian rhythm disruption and attentional deficits in different modalities in schizophrenia

Data-driven campaigning and democratic disruption : evidence from six advanced democracies

Data-driven campaigning has become one of the key foci for academic and non-academic audiences interested in political communication. Widely seen to have transformed political practice, it is often argued that data-driven campaigning is a force of significant democratic disruption because it contributes to a fragmentation of political discourse, undermines prevailing systems of electoral accountability and subverts ‘free’ and ‘fair’ elections. In this article, we present one of the very first cross-national analyses of data-driven campaigning by political parties. Drawing on empirical research conducted by experts in six advanced democracies, we show that the data-driven campaign practices seen to threaten democracy are often not manifest in party campaigns. Instead, we see a set of practices that build on pre-existing techniques and which are far less sophisticated than is often assumed. Indeed, we present evidence that most political parties lack the capacity to execute the hyper-intensive practices often associated with data-driven campaigning. Hence, while there is reason to remain alert to the challenges data-driven campaigning produces for democratic norms, we argue that this practice is not inherently disruptive, but rather exemplifies the evolving nature of political campaigning in the 21st century

Multi-centre point-prevalence survey of hospital-acquired infections in Ghana

Background: There is a paucity of data describing hospital-acquired infections (HAIs) in Africa. Objective: To describe the prevalence and distribution of HAIs in acute care hospitals in Ghana. Methods: Between September and December 2016, point-prevalence surveys were conducted in participating hospitals using protocols of the European Centre for Disease Prevention and Control. Medical records of eligible inpatients at or before 8am on the survey date were reviewed to identify HAIs present at the time of the survey. Findings: Ten hospitals were surveyed, representing 32.9% of all acute care beds in government hospitals. Of 2107 inpatients surveyed, 184 HAIs were identified among 172 patients, corresponding to an overall prevalence of 8.2%. The prevalence values in hospitals ranged from 3.5% to 14.4%, with higher proportions of infections in secondary and tertiary care facilities. The most common HAIs were surgical site infections (32.6%), bloodstream infections (19.5%), urinary tract infections (18.5%) and respiratory tract infections (16.3%). Device-associated infections accounted for 7.1% of HAIs. For 12.5% of HAIs, a micro-organism was reported; the most commonly isolated micro-organism was Escherichia coli. Approximately 61% of all patients surveyed were on antibiotics; 89.5% of patients with an HAI received at least one antimicrobial agent on the survey date. The strongest independent predictors for HAI were the presence of an invasive device before onset of infection and duration of hospital stay. Conclusion: A low HAI burden was found compared with findings from other low- and middle-income countries

A cross-sectional study of the nutritional status of community-dwelling people with idiopathic Parkinson's disease

<p>Abstract</p> <p>Background</p> <p>Parkinson's disease (PD) patients have an increased risk of under-nutrition, but we are unaware of any population based prevalence studies of under-nutrition in PD. The main objective of this study was to identify the prevalence, and nature, of under-nutrition in a representative population of people with PD.</p> <p>Methods</p> <p>People diagnosed with idiopathic PD from within two PD prevalence study sites in North-East England were asked to participate in this study. Those who participated (n = 136) were assessed using a number of standard rating scales including Hoehn & Yahr stage and Unified Parkinson's Disease Rating Scale (UPDRS). Body mass index (BMI), mid-arm circumference (MAC), triceps skin fold thickness (TSF) and grip strength were recorded together with social and demographic information.</p> <p>Results</p> <p>BMI < 20 identified over 15% of the study group to have under-nutrition. The Malnutritional Universal Screening Tool (MUST) scoring system identified 23.5% of participants at medium or high risk of malnutrition. Low BMI, indicating under-nutrition, was associated with greater age and disease duration, lower MAC, TSF, mid-arm muscle circumference (MAMC), reduced grip strength and a report of unintentional weight loss. Problems increased with increasing age and disease duration and were greater in females.</p> <p>Conclusions</p> <p>Under-nutrition is a problem for around 15% of community dwelling people with PD. All PD patients should be screened for under-nutrition; the MUST score is a useful early screening tool.</p

The Second Arden Shakespeare Series: A theoretical discussion and analysis

Acute light exposure exerts various effects on physiology and behaviour. Although the effects of light on brain network activity in humans are well demonstrated, the effects of light on cognitive performance are inconclusive, with the size, as well as direction, of the effect depending on the nature of the task. Similarly, in nocturnal rodents, bright light can either facilitate or disrupt performance depending on the type of task employed. Crucially, it is unclear whether the effects of light on behavioural performance are mediated via the classical image-forming rods and cones or the melanopsin-expressing photosensitive retinal ganglion cells. Here, we investigate the modulatory effects of light on memory performance in mice using the non-aversive, spontaneous recognition task. Importantly, we examine which photoreceptors are required to mediate the effects of light on memory performance. By using a cross-over design, we show that object recognition memory is disrupted when the test phase is conducted under a bright light (350 lux), regardless of the light level in the sample phase (10 or 350 lux), demonstrating that exposure to a bright light at the time of test, rather than at the time of encoding, impairs performance. Strikingly, the modulatory effect of light on memory performance is completely abolished in both melanopsin-deficient and rodless–coneless mice. Our findings provide direct evidence that melanopsin-driven and rod/cone-driven photoresponses are integrated in order to mediate the effect of light on memory performance