Theory of partial discharge and arc formation

The demand for electrical power has consistently risen over time, whether it be to support the development and expansion of cities or because traditional approaches to societies solutions are being replaced by their electrical equivalent. The automotive industry is beginning to introduce more electric, greener vehicles. The aviation industry is also being challenged with the same issues. Whatever the motivation, this rising demand for power is always facilitated by employing higher and higher voltage levels. It is well understood that if the voltage is too high for a given air gap, electric breakdown will occur. this effect is exacerbated by increases in altitude, resulting in constant challenges in aviation to satisfy the contradictory demands for smaller/lighter compact solutions against the biggest possible air gaps necessary to prevent electric breakdown. An experimental curve by Louis Karl Heinrich Friedrich Paschen was developed, which relates the voltage at which electric breakdown would be expected to that of the product of gas pressure (p) and distance (d). The aviation industry does not use this curve directly as alternate guidance documents are used. These documents are extremely conservative, sometimes overly so, as will be seen in the thesis. Mathematical attempts have been provided to try and explain the Paschen curve, based on Townsend Primary and secondary ionisation. However, the variable 'pd' does not get explicitly linked and a type of mathematical fudge becomes incorporated. This thesis attempts to provide a theory of the minimum electric breakdown curve and fundamentally link he 'pd' product. by experimental validation of the theory, with the accepted standards included. A basis for challenging these standards may result and prevent potential over engineering in the future in this continually challenging environment. This theory will then go on to explain arc formation by providing a treatment to a paradox that occurs at the point of breakdown

Examining Emailed Feedback as Boosters After a College Drinking Intervention Among Fraternities and Sororities: Rationale and Protocol for a Remote Controlled Trial (Project Greek)

BACKGROUND: College students involved in Greek life (ie, members of fraternities and sororities) tend to engage in more high-risk alcohol use and experience more negative consequences than those not involved in Greek life. Web-based alcohol interventions, such as Alcohol eCHECKUP TO GO, have been successful in reducing alcohol use and consequences among the general college student population, but interventions targeting alcohol reduction among those involved in Greek life have had limited success. Booster emails including personalized feedback regarding descriptive norms and protective behavioral strategies have shown potential in increasing the effectiveness of web-based interventions among college drinkers. Studies are needed to determine the efficacy of these boosters among those involved in Greek life. OBJECTIVE: The primary objective of this study is to assess the efficacy of booster emails sent to Greek life students who complete Alcohol eCHECKUP TO GO. Specifically, we expect that participants who receive the booster emails will reduce their alcohol consumption and related problems (primary aim 1), reduce perceived peer drinking, and increase the number of protective behavioral strategies they use over time (primary aim 2) relative to those who do not receive boosters. Contingent upon finding the emailed booster efficacious and sufficient enrollment of members from each organization, an exploratory aim is to examine social mechanisms of change (ie, through selection vs socialization). METHODS: This study is a remote, controlled intervention trial following participants for up to 6 months. Participants must be aged at least 18 years, undergraduate students, and members of a participating fraternity or sorority. Eligible participants complete a web-based baseline survey to assess their alcohol consumption behaviors and beliefs, including norms and protective behavioral strategies, and information about their social networks. After completing the baseline survey, they participate in the web-based intervention. Follow-up surveys are sent 1, 3, and 6 months after the intervention. Those in the booster condition also receive emails containing personalized feedback at 2 weeks and 14 weeks after the intervention. Latent growth models and R-Simulation Investigation for Empirical Network Analysis will be used to analyze the data. RESULTS: As of September 2022, we have enrolled 18 participants from 2 fraternities and 2 sororities, and they have completed the baseline survey. Overall, 72% (13/18) of participants have completed the 1-month follow-up. Enrollment will continue through December 2022. CONCLUSIONS: This study aims to examine the effectiveness of personalized feedback booster emails sent after an alcohol intervention among members of college Greek life. A secondary, exploratory aim is to provide information about social mechanisms of change (if possible). The current methodology targets whole network recruitment, with chapter presidents serving as gatekeepers and facilitators. Unique challenges of recruiting whole networks and working with campus administrators are discussed. TRIAL REGISTRATION: ClinicalTrials.gov NCT05107284; https://clinicaltrials.gov/ct2/show/NCT05107284. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/42535

Single-mode sapphire fiber Bragg grating

We present here the inscription of single-mode waveguides with Bragg gratings in sapphire. The waveguide Bragg gratings have a novel multi-layer depressed cladding design in the 1550 nm telecommunications waveband. The Bragg gratings have a narrow bandwidth (<0.5 nm) and have survived annealing at 1000{\deg}C. The structures are inscribed with femtosecond laser direct writing, using adaptive beam shaping with a non-immersion objective. A single-mode sapphire fiber Bragg grating is created by writing a waveguide with a Bragg grating within a 425 {\mu}m diameter sapphire optical fiber, providing significant potential for accurate remote sensing in ultra-extreme environments.Comment: Submitted to Optica 12 November 202

High-precision optical fiber sensing beyond 1000{\deg}C

Sapphire fiber can withstand around 2000{\deg}C, but it is multimoded, giving poor precision sensors. We demonstrate a single-mode sapphire fiber Bragg grating temperature sensor operating up to 1200{\deg}C. The repeatability above 1000{\deg}C is within {\pm}0.08%.Comment: 4 Pages, 5 Figure

Evaluation of multi-season convection permitting atmosphere - mixed layer ocean simulations of the Maritime Continent

A multi-season convection permitting regional climate simulation of the Maritime Continent using the Met Office Unified Model with 2.2-km grid spacing is presented and evaluated. The simulations pioneer the use of atmosphere-ocean coupling with the multi-column K profile parametrisation (KPP) mixed layer ocean model in atmospheric convection permitting climate simulations. Comparisons are made against a convection parametrised simulation in which it is nested, and which in turn derives boundary conditions from ERA5 reanalysis. This paper describes the configuration, performance of the mean state and variability of the two simulations compared against observational datasets. The models both have minor sea surface temperature (SST) and wet precipitation biases. The diurnal cycle, representation of equatorial waves and relationship between SST and precipitation are all improved in the convection permitting model compared to the convection parametrised model. The MJO is present in both models with a faster than observed propagation speed. However, it is unclear whether fidelity of the MJO simulation is inherent to the model or whether it predominantly arises from the forcing at the boundaries

Tiger sharks support the characterization of the world’s largest seagrass ecosystem

Seagrass conservation is critical for mitigating climate change due to the large stocks of carbon they sequester in the seafloor. However, effective conservation and its potential to provide nature-based solutions to climate change is hindered by major uncertainties regarding seagrass extent and distribution. Here, we describe the characterization of the world’s largest seagrass ecosystem, located in The Bahamas. We integrate existing spatial estimates with an updated empirical remote sensing product and perform extensive ground-truthing of seafloor with 2,542 diver surveys across remote sensing tiles. We also leverage seafloor assessments and movement data obtained from instrument-equipped tiger sharks, which have strong fidelity to seagrass ecosystems, to augment and further validate predictions. We report a consensus area of at least 66,000 km and up to 92,000 km of seagrass habitat across The Bahamas Banks. Sediment core analysis of stored organic carbon further confirmed the global relevance of the blue carbon stock in this ecosystem. Data from tiger sharks proved important in supporting mapping and ground-truthing remote sensing estimates. This work provides evidence of major knowledge gaps in the ocean ecosystem, the benefits in partnering with marine animals to address these gaps, and underscores support for rapid protection of oceanic carbon sinks

Impact of peer-led quality improvement networks on quality of inpatient mental health care: study protocol for a cluster randomized controlled trial

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Royal College of Psychiatrists’ College Centre for Quality Improvement (CCQI)

Phenotypic Characterization of EIF2AK4 Mutation Carriers in a Large Cohort of Patients Diagnosed Clinically With Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease with an emerging genetic basis. Heterozygous mutations in the gene encoding the bone morphogenetic protein receptor type 2 (BMPR2) are the commonest genetic cause of PAH, whereas biallelic mutations in the eukaryotic translation initiation factor 2 alpha kinase 4 gene (EIF2AK4) are described in pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Here, we determine the frequency of these mutations and define the genotype-phenotype characteristics in a large cohort of patients diagnosed clinically with PAH. METHODS: Whole-genome sequencing was performed on DNA from patients with idiopathic and heritable PAH and with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis recruited to the National Institute of Health Research BioResource-Rare Diseases study. Heterozygous variants in BMPR2 and biallelic EIF2AK4 variants with a minor allele frequency of <1:10 000 in control data sets and predicted to be deleterious (by combined annotation-dependent depletion, PolyPhen-2, and sorting intolerant from tolerant predictions) were identified as potentially causal. Phenotype data from the time of diagnosis were also captured. RESULTS: Eight hundred sixty-four patients with idiopathic or heritable PAH and 16 with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis were recruited. Mutations in BMPR2 were identified in 130 patients (14.8%). Biallelic mutations in EIF2AK4 were identified in 5 patients with a clinical diagnosis of pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Furthermore, 9 patients with a clinical diagnosis of PAH carried biallelic EIF2AK4 mutations. These patients had a reduced transfer coefficient for carbon monoxide (Kco; 33% [interquartile range, 30%-35%] predicted) and younger age at diagnosis (29 years; interquartile range, 23-38 years) and more interlobular septal thickening and mediastinal lymphadenopathy on computed tomography of the chest compared with patients with PAH without EIF2AK4 mutations. However, radiological assessment alone could not accurately identify biallelic EIF2AK4 mutation carriers. Patients with PAH with biallelic EIF2AK4 mutations had a shorter survival. CONCLUSIONS: Biallelic EIF2AK4 mutations are found in patients classified clinically as having idiopathic and heritable PAH. These patients cannot be identified reliably by computed tomography, but a low Kco and a young age at diagnosis suggests the underlying molecular diagnosis. Genetic testing can identify these misclassified patients, allowing appropriate management and early referral for lung transplantation

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements