Statistics of Solar Wind Electron Breakpoint Energies Using Machine Learning Techniques

Solar wind electron velocity distributions at 1 au consist of a thermal "core" population and two suprathermal populations: "halo" and "strahl". The core and halo are quasi-isotropic, whereas the strahl typically travels radially outwards along the parallel and/or anti-parallel direction with respect to the interplanetary magnetic field. With Cluster-PEACE data, we analyse energy and pitch angle distributions and use machine learning techniques to provide robust classifications of these solar wind populations. Initially, we use unsupervised algorithms to classify halo and strahl differential energy flux distributions to allow us to calculate relative number densities, which are of the same order as previous results. Subsequently, we apply unsupervised algorithms to phase space density distributions over ten years to study the variation of halo and strahl breakpoint energies with solar wind parameters. In our statistical study, we find both halo and strahl suprathermal breakpoint energies display a significant increase with core temperature, with the halo exhibiting a more positive correlation than the strahl. We conclude low energy strahl electrons are scattering into the core at perpendicular pitch angles. This increases the number of Coulomb collisions and extends the perpendicular core population to higher energies, resulting in a larger difference between halo and strahl breakpoint energies at higher core temperatures. Statistically, the locations of both suprathermal breakpoint energies decrease with increasing solar wind speed. In the case of halo breakpoint energy, we observe two distinct profiles above and below 500 km/s. We relate this to the difference in origin of fast and slow solar wind.Comment: Published in Astronomy & Astrophysics, 11 pages, 10 figure

The Balance Between Preventing Fraud and Ensuring Participation: Attitudes Towards Voter Identification in New Mexico

This paper examines public opinion on the effectiveness and consequences of voter identification laws in New Mexico. In particular, it focuses on the attitudes central to the court reasoning in the 2008 Supreme Court case which upheld an Indiana photo-ID law, Crawford v. Marion County Election Board. Questions include whether or not voters think the ID laws protect against fraud and prevent legitimate participation, as well as which point of view voters find more compelling and whether or not attitudes towards voter identification are related to voter confidence. While most voters think that voter ID laws prevent fraud, many voters think that ensuring access to the polls is more important than preventing fraud. Among other variables that explain differences among individuals, partisanship plays an important role.Caltech/MIT Voting Technology Projec

The Two-Tier Fecal Occult Blood Test: Cost-Effective Screening

The two-tier test represents a strategy combining HO Sensa and Hemeselect fecal occult blood tests (FOBTs) with the aim of greater specificity and consequent economic advantages. If patients register a positive result on any HO Sensa guaiac test, they are once again tested by a hemoglobin-specific Hemeselect test. This concept was applied to a multicentre study involving persons 40 years or older. One component of the study enrolled 573 high risk patients while the second arm recruited an additional 1301 patients (52% asymptomatic/48% symptomatic) stratified according to personal history and symptoms. The two-tier test produced fewer false positives than traditional tests in both groups evaluated in the study. In the high risk group, specificity (88.7% for two-tier versus 80.6% for Hemoccult and 69.5% for HO Sensa) was higher and false positive rates were lower (11.3% for two-tier versus 19.5% for Hemoccultand 30.5% for HO Sensa) for the two-tier test versus Hemoccult and HO Sensa FOBTs (95% CI for all colorectal cancers [CRCs] and polyps greater than 1 cm, α=0.05 ). No significant differences in sensitivity were observed between tests in the same group. Also, in the high risk group, benefits of the two-tier test outweighed the costs. Due to the small number of cancers and polyps in the second arm of the study, presentation of data is meant to be descriptive and representative of trends in a ‘normal’ population. Nevertheless, specificity of the two-tier test was higher (96.8% for two-tier versus 87.2% for Hemoccult and 69.5% for HO Sensa) and false positive rate lower (3.2% for two-tier versus 12.8% for Hemoccult and 22.3% for HO Sensa) than either the Hemoccult or HO Sensa FOBT (95% CI for all CRCs and polyps greater than 1 cm). This initial study, focusing on the cost-benefit relationship of increased specificity, represents a new way of economically evaluating existing FOBTs

A framework for synthesis of safety justification for digitally enabled healthcare services

Digitally enabled healthcare services combine socio-technical resources to deliver the required outcomes to patients. Unintended operation of these services may result in adverse effects to the patient. Eliminating avoidable harm requires a systematic way of analysing the causal conditions, identifying opportunities for intervention. Operators of such services may be required to justify, and communicate, their safety. For example, the UK Standardisation Committee for Care Information (SCCI) standards 0129 and 0160 require a safety justification for health IT (superseded versions were known as the Information Standards Board (ISB) 0129 & 0160. Initial as well as current standards are maintained by the NHS Digital.MethodA framework was designed, and applied as proof of concept, to an IT-supported clinical emergencies (A&E) service. Evaluation was done qualitatively based on the authors? experience, identifying potential benefits of the approach.ResultsThe applied framework encapsulates analysis, and structures the generated information, into a skeleton of an evidence-based case for safety. The framework improved management of the safety activities, assigning ownership to stakeholders (e.g. IT developer), also creating a clear and compelling safety justification.ConclusionsApplication of the framework significantly contributed to systematising an exploratory approach for analysing the service, in addition to existing methods such as reporting. Its application made the causal chain to harm more diaphanous. Constructing a safety case contributed to: (a) identifying potential assurance gaps, (b) planning production of information and evidence, and (c) communication of the justification by graphical unambiguous means

Pharmacological therapies for fibromyalgia (fibromyalgia syndrome) in adults – an overview of Cochrane Reviews (Protocol).

This is a protocol for a Cochrane Review (overview). The objectives are as follows:To provide an overview of the therapeutic efficacy of pharmacological therapies for fibromyalgia (fibromyalgia syndrome) in adults, and to report on adverse events associated with their use. The major comparison of interest will be with placebo

Cannabinoids on the Brain

Cannabis has a long history of consumption both for recreational and medicinal uses. Recently there have been significant advances in our understanding of how cannabis and related compounds (cannabinoids) affect the brain and this review addresses the current state of knowledge of these effects. Cannabinoids act primarily via two types of receptor, CB1 and CB2, with CB1 receptors mediating most of the central actions of cannabinoids. The presence of a new type of brain cannabinoid receptor is also indicated. Important advances have been made in our understanding of cannabinoid receptor signaling pathways, their modulation of synaptic transmission and plasticity, the cellular targets of cannabinoids in different central nervous system (CNS) regions and, in particular, the role of the endogenous brain cannabinoid (endocannabinoid) system. Cannabinoids have widespread actions in the brain: in the hippocampus they influence learning and memory; in the basal ganglia they modulate locomotor activity and reward pathways; in the hypothalamus they have a role in the control of appetite. Cannabinoids may also be protective against neurodegeneration and brain damage and exhibit anticonvulsant activity. Some of the analgesic effects of cannabinoids also appear to involve sites within the brain. These advances in our understanding of the actions of cannabinoids and the brain endocannabinoid system have led to important new insights into neuronal function which are likely to result in the development of new therapeutic strategies for the treatment of a number of key CNS disorders

Van Allen probes observations of a three-dimensional field line resonance at a plasmaspheric plume

Funding: JKS, KRM, and IJR acknowledge support from NERC Grants NE/P017185/2, NE/V002554/2, and STFC Grants ST/V006320/1, ST/X001008/1. DPH acknowledges NASA Grant 80NSSC20K1324. ANW was funded in part by STFC Grant ST/W001195/1. AWS was supported by NERC Independent Research Fellowship NE/W009129/1.Field Line Resonances (FLRs) are a critical component in Earth's magnetospheric dynamics, associated with the transfer of energy between Ultra Low Frequency waves and local plasma populations. In this study we investigate how the polarisation of FLRs are impacted by cold plasma density distributions during geomagnetic storms. We present an analysis of Van Allen Probe A observations, where the spacecraft traversed a storm time plasmaspheric plume. We show that the polarisation of the FLR is significantly altered at the sharp azimuthal density gradient of the plume boundary, where the polarisation is intermediate with significant poloidal and toroidal components. These signatures are consistent with magnetohydrodynamic modeling results, providing the first observational evidence of a 3D FLR associated with a plume in Earth's magnetosphere. These results demonstrate the importance of cold plasma in controlling wave dynamics in the magnetosphere, and have important implications for wave-particle interactions at a range of energies.Publisher PDFPeer reviewe

Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES

Young, rapidly-rotating M dwarfs exhibit prominent starspots, which create quasiperiodic signals in their photometric and Doppler spectroscopic measurements. The periodic Doppler signals can mimic radial velocity (RV) changes expected from orbiting exoplanets. Exoplanets can be distinguished from activity-induced false positives by the chromaticity and long-term incoherence of starspot signals, but these qualities are poorly constrained for fully-convective M stars. Coherent photometric starspot signals on M dwarfs may persist for hundreds of rotations, and the wavelength dependence of starspot RV signals may not be consistent between stars due to differences in their magnetic fields and active regions. We obtained precise multi-wavelength RVs of four rapidly-rotating M dwarfs (AD Leo, G 227-22, GJ 1245B, GJ 3959) using the near-infrared (NIR) Habitable-zone Planet Finder, and the optical Keck/HIRES spectrometer. Our RVs are complemented by photometry from Kepler, TESS, and the Las Cumbres Observatory (LCO) network of telescopes. We found that all four stars exhibit large spot-induced Doppler signals at their rotation periods, and investigated the longevity and optical-to-NIR chromaticity for these signals. The phase curves remain coherent much longer than is typical for Sunlike stars. Their chromaticity varies, and one star (GJ 3959) exhibits optical and NIR RV modulation consistent in both phase and amplitude. In general, though, we find that the NIR amplitudes are lower than their optical counterparts. We conclude that starspot modulation for rapidly-rotating M stars frequently remains coherent for hundreds of stellar rotations, and gives rise to Doppler signals that, due to this coherence, may be mistaken for exoplanets.Comment: Accepted for publication in the Astrophysical Journa