Survey Optimization via the Haphazard Intentional Sampling Method

In previously published articles, our research group has developed the Haphazard Intentional Sampling method and compared it to the Rerandomization method proposed by K.Morgan and D.Rubin. In this article, we compare both methods to the pure randomization method used for the Epicovid19 survey, conducted to estimate SARS-CoV-2 prevalence in 133 Brazilian Municipalities. We show that Haphazard intentional sampling can either substantially reduce operating costs to achieve the same estimation errors or, the other way around, substantially improve estimation precision using the same sample sizes.

Global sensitivity analysis of statistical models by double randomization method

The paper addresses a global sensitivity analysis of complex models. The work presents a generalization of the hierarchical statistical models where uncertain parameters determine the distribution of statistical models. The double randomization method is applied to increase the efficiency of the Monte Carlo estimation of Sobol indices. Numerical computations are provided to study the accuracy and efficiency of the proposed technique. The issue of optimization of the suggested approach is considered.

Comparison of RAMP and New Modified RAMP Positioning in Laryngoscopic View During Intubation in Patients with Morbid Obesity: A Randomized Clinical Trial

Background: The prevalence of obesity is increasing worldwide, and anesthesiologists are facing challenges in the airway management of such patients. Excessive adipose tissue influences pharyngeal spaces and affects the laryngoscopic grade. Standard ramp positioning is time-consuming and difficult to prepare, and requires expensive equipment. Objectives: The aim of this study was to compare the standard ramp position with the proposed low-cost and easily accessible modified ramp position in laryngoscopic view during the intubation of patients with morbid obesity. Methods: In this single-blind clinical trial, 84 patients candidate for bariatric surgery at Rasoul Akram Hospital in 2020 were assigned to the rapid airway management positioner (RAMP) (R) and new modified RAMP (MR) groups by the block randomization method. The laryngoscopic view of the glottis based on the Cormack-Lehane scale, ventilation quality, duration of intubation, intubation attempts, oxygen saturation at the end of intubation, and the need for backward, upward, rightward pressure (BURP) maneuver for successful intubation were recorded. Normal distribution tests and Mann-Whitney and Kruskal-Wallis tests were used to analyze the data. Results: The results showed no significant differences between the two groups regarding ventilation score, laryngoscopy grade, number of intubation attempts, duration of intubation, and the need for BURP maneuvers during intubation (P > 0.05). Conclusions: The two methods are not significantly different, and the new modified ramp position can be used with more ease and availability and less cost.

Applying the aggregated indices randomization method to prioritize cluster development

Subject. This article discusses the innovation activities of companies participating in clusters. Objectives. The article aims to justify a choice of State support facilities for the innovation activities of enterprises participating in clusters. Methods. For the study, we used the hierarchical aggregated indices randomization method and Monte Carlo method. Results. During the study of cluster construction in St. Petersburg, an array of data was obtained. Based on calculations, we show the choice of two enterprises, the best ones in terms of assessing the probability of dominance. We justify the possibility of using such a characteristic of randomized aggregated indices as the value of mathematical expectation, as a choice criterion. Conclusions. The algorithm developed to apply the aggregated indices randomization method develops an institutional approach to the analysis of regional clusters.

The Effectiveness of Intervention Based on the Transactional Model on Improving Coping Efforts and Stress Moderators in Hemodialysis Patients in Tehran

Background: Present study was conducted to determine the effect of training on coping efforts (CE) and stress moderators, based on transactional model of Lazarus and Folkman, in hemodialysis patients (HD). Methods: This is a randomized controlled clinical trial on 116 hemodialysis patients referred to dialysis centers in Tehran from May to August 2018. The patients were assigned to two experimental and control groups using a simple randomization method. The intervention included 6 training sessions in the form of CE and moderators of transactional model. Data were collected before and 3 months after the intervention. Data were analyzed using SPSS 16.Results: After 3 months training intervention, there was significant increase in the intervention group in the mean scores of CE (P<0.001), moderators and subscales of emotional regulation (ER) from 51.18 ± 20.42 to 64.87 ± 13.18 (P<0.001), dispositional coping style (DCS) from 45.56± 19.45 to 55.84± 18.03 and social support (SS) from 49.61 ±20.14 to 55.55 ± 17.35 (P<0.005).Conclusion: The training based on transactional model was successful in the increase of SS, DCS and ER in (HD). Therefore, Nurses and healthcare providers can use this program to help (HD) to increase their adaptation to the illness and reduce stress.

Smoking and COVID-19: A two-sample Mendelian randomization study

Evidence from observational studies suggested that smokers are at increased risk of coronavirus disease 2019 (COVID-19). We aimed to assess the causal effect of smoking on risk for COVID-19 susceptibility and severity using two-sample Mendelian randomization method. Smoking-associated variants were selected as instrument variables from two largest genetic studies. The latest summary data of COVID-19 that shared on Jan 18, 2021 by the COVID-19 Host Genetics Initiative was used. The present Mendelian randomization study provided genetic evidence that smoking was a causal risk factor for COVID-19 susceptibility and severity. In addition, there may be a dose-effect relationship between smoking and COVID-19 severity.