44 research outputs found
Effect of elevated blood pressure on quality of life in children with chronic kidney disease
Although hypertension is known to have an adverse impact on health-related quality of life (HRQoL) in adults, little is known about the effects of hypertension and use of antihypertensive medications on HRQoL in hypertensive children with chronic kidney disease (CKD)
Linear Stability Analysis for Plane-Poiseuille Flow of an Elastoviscoplastic fluid with internal microstructure
We study the linear stability of Plane Poiseuille flow of an
elastoviscoplastic fluid using a revised version of the model proposed by Putz
and Burghelea (Rheol. Acta (2009)48:673-689). The evolution of the
microstructure upon a gradual increase of the external forcing is governed by a
structural variable (the concentration of solid material elements) which decays
smoothly from unity to zero as the stresses are gradually increased beyond the
yield point. Stability results are in close conformity with the ones of a
pseudo-plastic fluid. Destabilizing effects are related to the presence of an
intermediate transition zone where elastic solid elements coexist with fluid
elements. This region brings an elastic contribution which does modify the
stability of the flow
Incidence of Primary End Point Changes Among Active Cancer Phase 3 Randomized Clinical Trials
IMPORTANCE: Primary end point (PEP) changes to an active clinical trial raise questions regarding trial quality and the risk of outcome reporting bias. It is unknown how the frequency and transparency of the reported changes depend on reporting method and whether the PEP changes are associated with trial positivity (ie, the trial met the prespecified statistical threshold for PEP positivity).
OBJECTIVES: To assess the frequency of reported PEP changes in oncology randomized clinical trials (RCTs) and whether these changes are associated with trial positivity.
DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used publicly available data for complete oncology phase 3 RCTs registered in ClinicalTrials.gov from inception through February 2020.
MAIN OUTCOMES AND MEASURES: The main outcome was change between the initial PEP and the final reported PEP, assessed using 3 methods: (1) history of tracked changes on ClinicalTrials.gov, (2) self-reported changes noted in the article, and (3) changes reported within the protocol, including all available protocol documents. Logistic regression analyses were performed to evaluate whether PEP changes were associated with US Food and Drug Administration approval or trial positivity.
RESULTS: Of 755 included trials, 145 (19.2%) had PEP changes found by at least 1 of the 3 detection methods. Of the 145 trials with PEP changes, 102 (70.3%) did not have PEP changes disclosed within the manuscript. There was significant variability in rates of PEP detection by each method (χ2 = 72.1; P \u3c .001). Across all methods, PEP changes were detected at higher rates when multiple versions of the protocol (47 of 148 [31.8%]) were available compared with 1 version (22 of 134 [16.4%]) or no protocol (76 of 473 [16.1%]) (χ2 = 18.7; P \u3c .001). Multivariable analysis demonstrated that PEP changes were associated with trial positivity (odds ratio, 1.86; 95% CI, 1.25-2.82; P = .003).
CONCLUSIONS AND RELEVANCE: This cross-sectional study revealed substantial rates of PEP changes among active RCTs; PEP changes were markedly underreported in published articles and mostly occurred after reported study completion dates. Significant discrepancies in the rate of detected PEP changes call into question the role of increased protocol transparency and completeness in identifying key changes occurring in active trials
Depressive Symptoms in Children with Chronic Kidney Disease
To assess depression in children with chronic kidney disease (CKD) and to determine associations with patient characteristics, intellectual and educational levels, and health related quality of life (HRQoL)
What Causes a System to Satisfy a Specification?
Even when a system is proven to be correct with respect to a specification, there is still a question of how complete the specification is, and whether it really covers all the behaviors of the system. Coverage metrics attempt to check which parts of a system are actually relevant for the verification process to succeed. Recent work on coverage in model checking suggests several coverage metrics and algorithms for finding parts of the system that are not covered by the specification. The work has already proven to be effective in practice, detecting design errors that escape early verification efforts in industrial settings. In this paper, we relate a formal definition of causality given by Halpern and Pearl [2005] to coverage. We show that it gives significant insight into unresolved issues regarding the definition of coverage and leads to potentially useful extensions of coverage. In particular, we introduce the notion of responsibility, which assigns to components of a system a quantitative measure of their relevance to the satisfaction of the specification.