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We present a detailed characterization of the structure and evolution of differentially rotating plasmas driven on the MAGPIE pulsed-power generator (1.4 MA peak current, 240 ns rise time). The experiments were designed to simulate physics relevant to accretion discs and jets on laboratory scales. A cylindrical aluminium wire array Z pinch enclosed by return posts with an overall azimuthal off-set angle was driven to produce ablation plasma flows that propagate inwards in a slightly off-radial trajectory, injecting mass, angular momentum and confining ram pressure to a rotating plasma column on the axis. However, the plasma is free to expand axially, forming a collimated, differentially rotating axial jet that propagates at ${\approx }100\,{\rm km}\,{\rm s}^{-1}$. The density profile of the jet corresponds to a dense shell surrounding a low-density core, which is consistent with the centrifugal barrier effect being sustained along the jet's propagation. We show analytically that, as the rotating plasma accretes mass, conservation of mass and momentum implies plasma radial growth scaling as $r \propto t^{1/3}$. As the characteristic moment of inertia increases, the rotation velocity is predicted to decrease and settle on a characteristic value ${\approx }20\,{\rm km}\,{\rm s}^{-1}$. We find that both predictions are in agreement with Thomson scattering and optical self-emission imaging measurements.
Significant advances in the research of sport-related concussion (SRC) and repetitive head impacts (RHI) over the previous decade have translated to improved injury identification, diagnosis, and management. However, an objective gold standard for SRC/RHI treatment has remained elusive. SRC often result in heterogenous clinical outcomes, and the accumulation of RHI over time is associated with long-term declines in neurocognitive functioning. Medical management typically entails an amalgamation of outpatient medical treatment and psychiatric and/or behavioral interventions for specific symptoms rather than treatment of the underlying functional and/or structural brain injury. Transcranial photobiomodulation (tPBM), a form of light therapy, has been proposed as a non-invasive treatment for individuals with traumatic brain injuries (TBI), possibly including SRC/RHI. With the present proof-of-concept pilot study, we sought to address important gaps in the neurorehabilitation of former athletes with a history of SRC and RHI by examining the effects of tPBM on neurocognitive functioning.
Participants and Methods:
The current study included 49 participants (45 male) with a history of SRC and/or RHI. Study inclusion criteria included: age 18-65 years and a self-reported history of SRC and/or RHI. Exclusion criteria included: a history of neurologic disease a history of psychiatric disorder, and MRI contraindication. We utilized a non-randomized proof-of-concept design of active treatment over the course of 8-10 weeks, and neurocognitive functioning was assessed at pre- and post-treatment. A Vielight Neuro Gamma at-home brain tPBM device was distributed to each participant following baseline assessment.
Participants completed standardized measures of neurocognitive functioning, including the California Verbal Learning Test (CVLT-3), Delis Kaplan Executive Function System (D-KEFS), Continuous Performance Test (CPT-3), and The NIH Toolbox Cognition Battery. Neurocognitive assessments were collected prior to and following tPBM treatment. Paired t-tests and Wilcoxon’s signed-rank tests were used to evaluate change in performance on measures of neurocognitive functioning for normal and nonnormal variables, respectively, and estimates of effect size were obtained.
Results:
Study participants’ ability for adapting to novel stimuli and task requirements (i.e., fluid cognition; t=5.96; p<.001; d=.90), verbal learning/encoding (t=3.20; p=.003; d=.48) and delayed recall (z=3.32; p=.002; d=.50), processing speed (t=3.13; p=.003; d=.47), sustained attention (t=-4.39; p<.001; d=-.71), working memory (t=3.61; p=.001; d=.54), and aspects of executive functioning improved significantly following tPBM treatment. No significant improvements in phonemic and semantic verbal fluencies, reading ability, and vocabulary were shown following tPBM treatment.
Conclusions:
The results of this pilot study demonstrate that following 8-10 weeks of active tPBM treatment, retired athletes with a history of SRC and/or RHI experienced significant improvements in fluid cognition, learning and memory, processing speed, attention, working memory, and aspects of executive functioning. Importantly, the majority of effect sizes ranged from moderate to large, suggesting that tPBM has clinically meaningful improvements on neurocognitive functioning across various cognitive domains. These results offer support for future research employing more rigorous study designs on the potential neurorehabilitative effects of tPBM in athletes with SRC/RHI.
Mental health problems are common in children and young people (CYP) in England, yet evidence suggests high levels of unmet need in this group. Understanding of the determinants of mental health-related service contact is needed to identify gaps in service provision and areas for targeted intervention to improve access.
Objectives
To determine the relationship between CYP characteristics and mental health-related support and service contact in England.
Methods
A secondary analysis of the 2017 NHS Digital Mental Health of Children and Young People (MHCYP-2017) cross-sectional survey dataset was performed. MHCYP-2017 was a national survey investigating the mental health of CYP using a stratified multistage random probability sampling approach, providing the official national statistics for England. Multi-informant data were collected through a combination of questionnaires and interviews. Expert clinical rating took place to formally identify the presence of mental disorders, according to established diagnostic criteria. This secondary analysis describes mental health-related support and service contact amongst 6681 participants aged 5-16 recruited to the MHCYP-2017 study. A range of socio-demographic and clinical characteristics were analysed as explanatory variables and their relationships with different types of support/service contact were examined through multivariable multinomial logistic regression. Analyses were stratified by age group: 5-10- and 11-16-year-olds.
Results
Overall, around 25% of parents reported CYP mental health-related contact with one or more types of support/service in the past 12 months due to concerns regarding CYP “emotions, behaviour, concentration or difficulties in getting along with people”. Age stratified multivariable analyses revealed several statistically significant associations between participant socio-demographic/clinical characteristics and mental health-related support and service contact, independent of CYP mental health status and parental perception of difficulties. These associations were not necessarily consistent across mental health support categories, suggesting that several of the measured characteristics have differential relationships with different types of support and service contact. Whilst there were some differences between the 5-10 and 11-16 age groups, similar associations were seen for many of the explanatory variables. Socioeconomically disadvantaged and black and minority ethnic CYP were less likely to have had professional contact for mental health problems.
Conclusions
There may be higher levels of unmet need in socioeconomically disadvantaged and black and minority ethnic CYP, warranting further investigation and efforts to address inequalities. Further longitudinal studies are needed to elucidate causal associations and mechanisms underlying these observations.
We present the third data release from the Parkes Pulsar Timing Array (PPTA) project. The release contains observations of 32 pulsars obtained using the 64-m Parkes ‘Murriyang’ radio telescope. The data span is up to 18 yr with a typical cadence of 3 weeks. This data release is formed by combining an updated version of our second data release with $\sim$3 yr of more recent data primarily obtained using an ultra-wide-bandwidth receiver system that operates between 704 and 4032 MHz. We provide calibrated pulse profiles, flux density dynamic spectra, pulse times of arrival, and initial pulsar timing models. We describe methods for processing such wide-bandwidth observations and compare this data release with our previous release.
Recruiting underrepresented people and communities in research is essential for generalizable findings. Ensuring representative participants can be particularly challenging for practice-level dissemination and implementation trials. Novel use of real-world data about practices and the communities they serve could promote more equitable and inclusive recruitment.
Methods:
We used a comprehensive primary care clinician and practice database, the Virginia All-Payers Claims Database, and the HealthLandscape Virginia mapping tool with community-level socio-ecological information to prospectively inform practice recruitment for a study to help primary care better screen and counsel for unhealthy alcohol use. Throughout recruitment, we measured how similar study practices were to primary care on average, mapped where practices’ patients lived, and iteratively adapted our recruitment strategies.
Results:
In response to practice and community data, we adapted our recruitment strategy three times; first leveraging relationships with residency graduates, then a health system and professional organization approach, followed by a community-targeted approach, and a concluding approach using all three approaches. We enrolled 76 practices whose patients live in 97.3% (1844 of 1907) of Virginia’s census tracts. Our overall patient sample had similar demographics to the state for race (21.7% vs 20.0% Black), ethnicity (9.5% vs 10.2% Hispanic), insurance status (6.4% vs 8.0% uninsured), and education (26.0% vs 32.5% high school graduate or less). Each practice recruitment approach uniquely included different communities and patients.
Discussion:
Data about primary care practices and the communities they serve can prospectively inform research recruitment of practices to yield more representative and inclusive patient cohorts for participation.
Despite the impact of inappropriate prescribing on antibiotic resistance, data on surgical antibiotic prophylaxis in sub-Saharan Africa are limited. In this study, we evaluated antibiotic use and consumption in surgical prophylaxis in 4 hospitals located in 2 geographic regions of Sierra Leone.
Methods:
We used a prospective cohort design to collect data from surgical patients aged 18 years or older between February and October 2021. Data were analyzed using Stata version 16 software.
Results:
Of the 753 surgical patients, 439 (58.3%) were females, and 723 (96%) had received at least 1 dose of antibiotics. Only 410 (54.4%) patients had indications for surgical antibiotic prophylaxis consistent with local guidelines. Factors associated with preoperative antibiotic prophylaxis were the type of surgery, wound class, and consistency of surgical antibiotic prophylaxis with local guidelines. Postoperatively, type of surgery, wound class, and consistency of antibiotic use with local guidelines were important factors associated with antibiotic use. Of the 2,482 doses administered, 1,410 (56.8%) were given postoperatively. Preoperative and intraoperative antibiotic use was reported in 645 (26%) and 427 (17.2%) cases, respectively. The most commonly used antibiotic was ceftriaxone 949 (38.2%) with a consumption of 41.6 defined daily doses (DDD) per 100 bed days. Overall, antibiotic consumption was 117.9 DDD per 100 bed days. The Access antibiotics had 72.7 DDD per 100 bed days (61.7%).
Conclusions:
We report a high rate of antibiotic consumption for surgical prophylaxis, most of which was not based on local guidelines. To address this growing threat, urgent action is needed to reduce irrational antibiotic prescribing for surgical prophylaxis.
The seroprevalence of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) IgG antibody was evaluated among employees of a Veterans Affairs healthcare system to assess potential risk factors for transmission and infection.
Methods:
All employees were invited to participate in a questionnaire and serological survey to detect antibodies to SARS-CoV-2 as part of a facility-wide quality improvement and infection prevention initiative regardless of clinical or nonclinical duties. The initiative was conducted from June 8 to July 8, 2020.
Results:
Of the 2,900 employees, 51% participated in the study, revealing a positive SARS-CoV-2 seroprevalence of 4.9% (72 of 1,476; 95% CI, 3.8%–6.1%). There were no statistically significant differences in the presence of antibody based on gender, age, frontline worker status, job title, performance of aerosol-generating procedures, or exposure to known patients with coronavirus infectious disease 2019 (COVID-19) within the hospital. Employees who reported exposure to a known COVID-19 case outside work had a significantly higher seroprevalence at 14.8% (23 of 155) compared to those who did not 3.7% (48 of 1,296; OR, 4.53; 95% CI, 2.67–7.68; P < .0001). Notably, 29% of seropositive employees reported no history of symptoms for SARS-CoV-2 infection.
Conclusions:
The seroprevalence of SARS-CoV-2 among employees was not significantly different among those who provided direct patient care and those who did not, suggesting that facility-wide infection control measures were effective. Employees who reported direct personal contact with COVID-19–positive persons outside work were more likely to have SARS-CoV-2 antibodies. Employee exposure to SARS-CoV-2 outside work may introduce infection into hospitals.
The deviation from thermodynamic equilibrium of the ion velocity distribution functions (VDFs), as measured by the Magnetospheric Multiscale (MMS) mission in the Earth’s turbulent magnetosheath, is quantitatively investigated. Making use of the unprecedented high-resolution MMS ion data, and together with Vlasov–Maxwell simulations, this analysis aims at investigating the relationship between deviation from Maxwellian equilibrium and typical plasma parameters. Correlations of the non-Maxwellian features with plasma quantities such as electric fields, ion temperature, current density and ion vorticity are found to be similar in magnetosheath data and numerical experiments, with a poor correlation between distortions of ion VDFs and current density, evidence that questions the occurrence of VDF departure from Maxwellian at the current density peaks. Moreover, strong correlation has been observed with the magnitude of the electric field in the turbulent magnetosheath, while a certain degree of correlation has been found in the numerical simulations and during a magnetopause crossing by MMS. This work could help shed light on the influence of electrostatic waves on the distortion of the ion VDFs in space turbulent plasmas.
When a layer of static grains on a sufficiently steep slope is disturbed, an upslope-propagating erosion wave, or retrogressive failure, may form that separates the initially static material from a downslope region of flowing grains. This paper shows that a relatively simple depth-averaged avalanche model with frictional hysteresis is sufficient to capture a planar retrogressive failure that is independent of the cross-slope coordinate. The hysteresis is modelled with a non-monotonic effective basal friction law that has static, intermediate (velocity decreasing) and dynamic (velocity increasing) regimes. Both experiments and time-dependent numerical simulations show that steadily travelling retrogressive waves rapidly form in this system and a travelling wave ansatz is therefore used to derive a one-dimensional depth-averaged exact solution. The speed of the wave is determined by a critical point in the ordinary differential equation for the thickness. The critical point lies in the intermediate frictional regime, at the point where the friction exactly balances the downslope component of gravity. The retrogressive wave is therefore a sensitive test of the functional form of the friction law in this regime, where steady uniform flows are unstable and so cannot be used to determine the friction law directly. Upper and lower bounds for the existence of retrogressive waves in terms of the initial layer depth and the slope inclination are found and shown to be in good agreement with the experimentally determined phase diagram. For the friction law proposed by Edwards et al. (J. Fluid. Mech., vol. 823, 2017, pp. 278–315, J. Fluid. Mech., 2019, (submitted)) the magnitude of the wave speed is slightly under-predicted, but, for a given initial layer thickness, the exact solution accurately predicts an increase in the wave speed with higher inclinations. The model also captures the finite wave speed at the onset of retrogressive failure observed in experiments.
Chondritic meteorites, and especially the most volatile-rich chondrites, the carbonaceous chondrites, preserve a record of the solar protoplanetary disk dust component and how it has been changed both in the disk environment itself and in its asteroidal parent body. Here we review some of the key features of carbonaceous chondrites and report some new data on their organics component. These show that the nebula reached temperature of >10000C, but only very locally, to produce chondrules. Most meteoritic material underwent thermal and/or aqueous processing, but some retain delicate nebular components such as complex organic molecules and amorphous silicates.
Oral anticoagulation (OAC) reduces stroke risk in patients with atrial fibrillation (AF) or atrial flutter (AFL). However, OAC initiation rates in patients discharged directly from the emergency department (ED) are low. We aimed to address this care gap by implementing a quality improvement intervention.
Methods
The study was performed in four Canadian urban EDs between 2015 and 2016. Patients were included if they had an electrocardiogram (ECG) documenting AF/AFL in the ED, were directly discharged from the ED, and were alive after 90 days. Baseline rates of OAC initiation were determined prior to the intervention. Between June and December 2016, we implemented our intervention in two EDs (ED-intervention), with the remaining sites acting as controls (ED-control). The intervention included a reminder statement prompting OAC initiation according to guideline recommendations, manually added to ECGs with a preliminary interpretation of AF/AFL, along with a decision-support algorithm that included a referral sheet. The primary outcome was the rate of OAC initiation within 90 days of the ED visit.
Results
Prior to the intervention, 37.2% OAC-naïve patients with ECG-documented AF/AFL were initiated on OAC. Following implementation of the intervention, the rate of OAC initiation increased from 38.6% to 47.5% (absolute increase of 8.5%; 95% CI, 0.3% to 16.7%, p=0.04) among the ED-intervention sites, whereas the rate remained unchanged in ED-control sites (35.3% to 35.9%, p=0.9).
Conclusions
Implementation of a quality improvement intervention consisting of a reminder and decision-support tool increased initiation of OAC in high-risk patients. This support package can be readily implemented in other jurisdictions to improve OAC rates for AF/AFL.