Search results for "Random"

Stochastic dynamics of nonlinear systems driven by non-normal delta-correlated processes

1993

In this paper, nonlinear systems subjected to external and parametric non-normal delta-correlated stochastic excitations are treated. A new interpretation of the stochastic differential calculus allows first a full explanation of the presence of the Wong-Zakai or Stratonovich correction terms in the Itoˆ’s differential rule. Then this rule is extended to take into account the non-normality of the input. The validity of this formulation is confirmed by experimental results obtained by Monte Carlo simulations.

Higher order statistics of the response of linear systems excited by polynomials of filtered Poisson pulses

1999

The higher order statistics of the response of linear systems excited by polynomials of filtered Poisson pulses are evaluated by means of knowledge of the first order statistics and without any further integration. This is made possible by a coordinate transformation which replaces the original system by a quasi-linear one with parametric Poisson delta-correlated input; and, for these systems, a simple relationship between first order and higher order statistics is found in which the transition matrix of the dynamical new system, incremented by the correction terms necessary to apply the Ito calculus, appears.

A Randomized Controlled Trial Comparing Inhaled Isoflurane Via the Anaesthetic Conserving Device (Sedaconda <sup>®</sup> ACD) with Propof…

2021

Background: Small studies indicate that isoflurane may be useful for sedation during invasive ventilation of ICU patients. There are no published large prospective efficacy trials. Methods: This phase 3, non-inferiority trial evaluated the efficacy and safety of ≤54 hours of isoflurane via the anaesthetic conserving device (ACD) compared with propofol in invasively ventilated ICU patients (30-day follow-up). Primary endpoint was percentage of time in Richmond Agitation–Sedation Scale (RASS) range –1 to –4; the predefined non-inferiority margin was 15% below the propofol mean. Secondary endpoints: opioid requirements, spontaneous breathing during sedation, time to wake-up and extubation, adv…

Supportive und adjunktive Therapiemaßnahmen bei akutem Lungenversagen

2008

Various supportive and adjunctive therapies to conventional mechanical ventilation have been evaluated in patients with acute lung injury and acute respiratory distress syndrome (e.g. nitric oxide, prone position, surfactant, glucocorticoids). Although some investigations have shown promising improvements in oxygenation and physiological variables, large randomized trials of adjunctive and supportive therapies showed no impact on survival.

How and for whom does a positive affect intervention work in fibromyalgia: An analysis of mediators and moderators.

2019

Objectives: Psychological interventions designed to enhance positive affect are promising ways to promote adaptive functioning in people with chronic pain. However, few studies have addressed the efficacy of positive affect interventions in chronic pain populations and examined which patients can benefit more from them. The aim of the present study was to identify mediators and moderators of the best possible self intervention (BPS) in fibromyalgia patients.Methods: We used data from a previous randomized controlled trial that examined changes in pain interference, depression, self‐efficacy and quality of life after the BPS intervention.Results: Mediation analyses showed that depression med…

2022

This study quantifies the causal effect of birth weight on cardiovascular biomarkers in adulthood using the Cardiovascular Risk in Young Finns Study (YFS). We apply a multivariable Mendelian randomization (MVMR) method that provides a novel approach to improve inference in causal analysis based on a mediation framework. The results show that birth weight is linked to triglyceride levels (β = -0.294; 95% CI [-0.591, 0.003]) but not to low-density lipoprotein (LDL) cholesterol levels (β = 0.007; 95% CI [-0.168, 0.183]). The total effect of birth weight on triglyceride levels is partly offset by a mediation pathway linking birth weight to adult BMI (β = 0.111; 95% CI [-0.013, 0.234]). The nega…

Aerobic fitness mediates the intervention effects of a school-based physical activity intervention on academic performance. The school in Motion stud…

2021

Highlights • Physical activity is associated with increased aerobic fitness and academic performance. • Little is known on mechanism of physical activity effects on academic performance. • We performed a cluster randomized controlled trial. • Aerobic fitness mediated the intervention effect on academic performance. • Activity increasing aerobic fitness is a strategy to improve academic performance.

Mechanisms of Smartphone Apps for Cigarette Smoking Cessation: Results of a Serial Mediation Model From the iCanQuit Randomized Trial

2021

Background Engagement with digital interventions is a well-known predictor of treatment outcomes, but this knowledge has had limited actionable value. Instead, learning why engagement with digital interventions impact treatment outcomes can lead to targeted improvements in their efficacy. Objective This study aimed to test a serial mediation model of an Acceptance and Commitment Therapy (ACT) smartphone intervention for smoking cessation. Methods In this randomized controlled trial, participants (N=2415) from 50 US states were assigned to the ACT-based smartphone intervention (iCanQuit) or comparison smartphone intervention (QuitGuide). Their engagement with the apps (primary measure: numb…

Safety self-efficacy and internal locus of control as mediators of safety motivation – Randomized controlled trial (RCT) study

2019

Abstract Behavioral factors play a fundamental role in preventing occupational injuries and accidents. Previous studies have shown that engagement in safety behavior is influenced by workers’ safety motivation. However, understanding of the cognitive factors that contribute to safety motivation is lacking. In this study, we examine internal safety locus of control and safety self-efficacy as mediators of the effects of a safety intervention on safety motivation. In 2016, 464 students from eight vocational schools participated in a school-based cluster randomized, controlled intervention study conducted in Finland. In the multiple mediation model investigated using structural equation modeli…

Anxiety and the severity of Tension-Type Headache mediate the relation between headache presenteeism and workers’ productivity

2018

The primary objective of this study was to explore the mechanisms and conditions whereby Tension-Type Headache (TTH) presenteeism relates to health-related loss of productivity as a result of both reduced physical and mental health. To this end, Structural Equation Modeling (SEM) was used to conduct a secondary data analysis of a randomized clinical trial involving 78 Tension-type Headache (TTH) patients. The results showed that TTH presenteeism did not directly relate to health-related loss of productivity, either due to physical, or mental health problems. However, through anxiety-state, TTH presenteeism decreased patients' productivity, as consequence of reduced physical and mental healt…