Mechanics of hydrogen-dislocation-impurity interactions: part 1- increasing shear modulus

The effect of hydrogen on dislocation-dislocation and dislocation-impurity atom interactions is studied under conditions where hydrogen is in equilibrium with local stresses and in systems where hydrogen increases the shear modulus. In the case of two edge dislocations (plain strain) the effect of hydrogen is modeled through a continous distribution of dilatation lines whose strength depends on the local hydrogen concentration. The hydrogen distribution in the atmospheres is adjusted to minimize the energy of the system as the dislocations approach each other. The iterative finite element analysis used to calculate the hydrogen distribution accounts for the stress relaxation associated with the hydrogen induced volume and the elastic moduli changes due to hydrogen. The interactions between the dislocations are calculated accounting for all the stress fields due to dislocations and hydrogen atmospheres. An analytical formula is suggested for the hydrogen induced reduction in the magnitude of the shear stress exerted between the dislocations along the slip system. Modeling of the hydrogen effect on the edge dislocation-interstitial solute atom interaction is discussed using a finite element analysis and a formula is developed for the calculation of the dislocation-solute atom interaction energy in the presence of hydrogen. In this paper the numerical results are presented for the case where hydrogen increases the shear modulus of the metallic system. A significant decrease of the edge dislocation-intersititial solid atom interaction energy was observed when the dislocation-solute distance is approximately less than 2 Burgers vectors. This can be attributed almost entirely to the modulus change due to hydrogen. The effect of hydrogen on the screw dislocation-intersitial solute interaction was investigated. Numerical results indicate that, depeneding on the orientation of the tetragonal axis of the carbon distortion field, hydrogen may strengthen or weaken the interaction. The present model provides strong support for the hydrogen shielding mechanism wherby hydrogen diminishes the local stress fields from dislocation and solutes which act as barriers to the dislocation motion

IRA Propaganda on Twitter: Stoking Antagonism and Tweeting Local News

This paper presents preliminary findings of a content analysis of tweets posted by false accounts operated by the Internet Research Agency (IRA) in St Petersburg . We relied on a historical database of tweets to retrieve 4539 tweets posted by IRA-linked accounts in 2012-2017 and coded 2501 tweets manually . The messages cover US newsworthy events , the Charlie Hebdo terrorist attack in 2015, and the Brexit referendum in 2016. Tweets were annotated using 19 control variables to investigate whether IRA operations on social media are consistent with classic propaganda models. The results show that the IRA operates a composite of user account s tailored to perform specific tasks , with the lion’s share of their work focusing on US daily news activity and the diffusion of polarized news across different national contexts

Dancing to the Partisan Beat: A First Analysis of Political Communication on TikTok

TikTok is a video-sharing social networking service, whose popularity is increasing rapidly. It was the world's second-most downloaded app in 2019. Although the platform is known for having users posting videos of themselves dancing, lip-syncing, or showcasing other talents, user-videos expressing political views have seen a recent spurt. This study aims to perform a primary evaluation of political communication on TikTok. We collect a set of US partisan Republican and Democratic videos to investigate how users communicated with each other about political issues. With the help of computer vision, natural language processing, and statistical tools, we illustrate that political communication on TikTok is much more interactive in comparison to other social media platforms, with users combining multiple information channels to spread their messages. We show that political communication takes place in the form of communication trees since users generate branches of responses to existing content. In terms of user demographics, we find that users belonging to both the US parties are young and behave similarly on the platform. However, Republican users generated more political content and their videos received more responses; on the other hand, Democratic users engaged significantly more in cross-partisan discussions.Comment: Accepted as a full paper at the 12th International ACM Web Science Conference (WebSci 2020). Please cite the WebSci version; Second version includes corrected typo

Excess Costs Associated with Possible Misdiagnosis of Alzheimer's Disease Among Patients with Vascular Dementia in a UK CPRD Population

The authors would like to acknowledge Julie von Ziegenweidt and Annie Burden (Research in Real Life, UK) for assistance with processing and interpretation of CPRD data, and Gillian Gummer and Caroline Spencer (Rx Communications, Mold, UK) for medical writing assistance with the preparation of this article, funded by Eli Lilly and Company. Authors’ disclosures available online (http://j-alz. com/manuscript-disclosures/15-0685r2).Peer reviewedPublisher PD

A Phase I Study of Dasatinib with Concurrent Chemoradiation for Stage III Non-Small Cell Lung Cancer

Objectives: Src family kinases (SFKs) are expressed in non-small cell lung cancer (NSCLC) and may be involved in tumor growth and metastases. Inhibition of SFK may also enhance radiation. The purpose of this study was to evaluate if a maximum dose of 100 mg of dasatinib could be safely administered with concurrent chemoradiation and then continued as maintenance for patients with newly diagnosed stage III NSCLC. Methods: Patients with stage III locally advanced NSCLC received paclitaxel, 50 mg/m2/week, with carboplatin area under the curve (AUC) = 2, weekly for 7 weeks, and concurrent radiotherapy, 64.8 Gy. Three dose levels of dasatinib 50, 70, and 100 mg/day were planned. Results: 11 patients with locally advanced NSCLC were entered. At the 70 mg dose level 1 patient had grade 5 pneumonitis not responsive to therapy, and one patient had reversible grade 3 pneumonitis and grade 3 pericardial effusion. Due to these toxicities the Brown University Oncology Group Data Safety Monitoring Board terminated the study. Conclusion: Dasatinib could not be safely combined with concurrent chemoradiation for stage 3 lung cancer due to pneumonitis

Cardiovascular and Economic Outcomes After Initiation of Lipid-Lowering Therapy With Atorvastatin vs Simvastatin in an Employed Population

OBJECTIVE: To compare the risk of cardiovascular-related hospitalization, statin adherence, and direct (medical and drug) and indirect (disability and medically related absenteeism) costs in US employees in whom atorvastatin or simvastatin was newly prescribed

FORENSIC PAIN MEDICINE SECTION Original Research Article Societal Costs of Prescription Opioid Abuse, Dependence, and Misuse in the United Statesp me_1075 657..667

Abstract Objectives. The objective of this study was to estimate the societal costs of prescription opioid abuse, dependence, and misuse in the United States. Methods. Costs were grouped into three categories: health care, workplace, and criminal justice. Costs were estimated by 1) quantity method, which multiplies the number of opioid abuse patients by cost per opioid abuse patient; and 2) apportionment method, which begins with overall costs of drug abuse per component and apportions the share associated with prescription opioid abuse based on relative prevalence of prescription opioid to overall drug abuse. Excess health care costs per patient were based on claims data analysis of privately insured and Medicaid beneficiaries. Other data/ information were derived from publicly available survey and other secondary sources. Conclusions. The costs of prescription opioid abuse represent a substantial and growing economic burden for the society. The increasing prevalence of abuse suggests an even greater societal burden in the future

SARS-CoV-2 infection, clinical features and outcome of COVID-19 in United Kingdom nursing homes.

OBJECTIVES: To understand SARS-Co-V-2 infection and transmission in UK nursing homes in order to develop preventive strategies for protecting the frail elderly residents. METHODS: An outbreak investigation involving 394 residents and 70 staff, was carried out in 4 nursing homes affected by COVID-19 outbreaks in central London. Two point-prevalence surveys were performed one week apart where residents underwent SARS-CoV-2 testing and had relevant symptoms documented. Asymptomatic staff from three of the four homes were also offered SARS-CoV-2 testing. RESULTS: Overall, 26% (95% CI 22-31) of residents died over the two-month period. All-cause mortality increased by 203% (95% CI 70-336) compared with previous years. Systematic testing identified 40% (95% CI 35-46) of residents as positive for SARS-CoV-2, and of these 43% (95% CI 34-52) were asymptomatic and 18% (95% CI 11-24) had only atypical symptoms; 4% (95% CI -1 to 9) of asymptomatic staff also tested positive. CONCLUSIONS: The SARS-CoV-2 outbreak in four UK nursing homes was associated with very high infection and mortality rates. Many residents developed either atypical or had no discernible symptoms. A number of asymptomatic staff members also tested positive, suggesting a role for regular screening of both residents and staff in mitigating future outbreaks

Educational development between faculty and administration

This essay employs Identity Theory to explore the professional identities of educational developers, arguing that it is important to pay attention to the different saliences, or weights, that developers attach to the faculty and administrative sides of their identities

A comparison of missing data methods for hypothesis tests of the treatment effect in substance abuse clinical trials: a Monte-Carlo simulation study

<p>Abstract</p> <p>Background</p> <p>Missing data due to attrition are rampant in substance abuse clinical trials. However, missing data are often ignored in the presentation of substance abuse clinical trials. This paper demonstrates missing data methods which may be used for hypothesis testing.</p> <p>Methods</p> <p>Methods involving stratifying and weighting individuals based on missing data pattern are shown to produce tests that are robust to missing data mechanisms in terms of Type I error and power. In this article, we describe several methods of combining data that may be used for testing hypotheses of the treatment effect. Furthermore, illustrations of each test's Type I error and power under different missing data percentages and mechanisms are quantified using a Monte-Carlo simulation study.</p> <p>Results</p> <p>Type I error rates were similar for each method, while powers depended on missing data assumptions. Specifically, power was greatest for the weighted, compared to un-weighted methods, especially for greater missing data percentages.</p> <p>Conclusion</p> <p>Results of this study as well as extant literature demonstrate the need for standards of design and analysis specific to substance abuse clinical trials. Given the known substantial attrition rates and concern for the missing data mechanism in substance abuse clinical trials, investigators need to incorporate missing data methods a priori. That is, missing data methods should be specified at the outset of the study and not after the data have been collected.</p