Search results for "errors"

A novel approach to current transformer characterization in the presence of harmonic distortion

2009

The current transformer (CT) performance under distorted waveform conditions is usually characterized by means of the frequency-response test. In this paper, a new way to characterize CTs, closer to real operation conditions, is proposed. The harmonic phase-angle and ratio errors are measured using a nonsinusoidal current composed of fundamental and one harmonic with adjustable phase shift. The new method was tested by determining the performance of two metering class CTs commonly used by the Italian power company. The errors measured using the proposed approach are larger than the ones obtained with the frequency response. This result suggests that the frequency-response approach for the e…

Missing Cases of Herpes Simplex Virus (HSV) Infection of the Central Nervous System When the Reller Criteria Are Applied for HSV PCR Testing: a Multi…

2019

ABSTRACT Previous studies suggested that herpes simplex virus (HSV) PCR testing can be safely deferred in patients with normal cerebrospinal fluid (CSF) white blood cell (WBC) counts and protein levels as long as they are older than 2 years of age and are not immunocompromised, the so-called Reller criteria. In this multicenter study, we retrospectively assessed the validity of these screening criteria in our setting. A total of 4,404 CSF specimens submitted for HSV PCR testing to the respective microbiology laboratories at the participating hospitals between 2012 and 2018 were included. Six commercially available HSV PCR assays were used across the participating centers. Ninety-one of the …

Diagnostic morphology of human eye-related storage disorders

1989

While retina and other ocular tissues are involved clinically and morphologically in a variety of lysosomal disorders, it is only the conjunctiva that is accessible by biopsy to morphological, i.e., electron microscopic recognition of the patient's individual lysosomal disease. However, this procedure is not utilized by many. Instead, skin and circulating lymphocytes are the most frequently obtained tissues for diagnostic investigation, as skin contains an abundance of diversified cell types for morphological examination and simultaneously fibroblasts to be cultured for biochemical investigation. It is the tissue most suitable for identifying lysosomal disorders and parallels in diagnostic …

ITPA deficiency and ribavirin level are still predictive of anaemia in HCV–HIV-coinfected patients receiving ribavirin combined with a first-generati…

2017

Background We aimed to determine the impact of inosine triphosphatase (ITPA) deficiency on ribavirin (RBV)-induced anaemia in HIV–HCV-coinfected patients receiving a triple therapy including the haematotoxic direct-acting antiviral agent boceprevir (BOC). Methods Patients of the ANRS HC27 BocepreVIH study were genotyped for two ITPA single nucleotide polymorphisms involved in ITPA deficiency. RBV trough concentration (Ctrough) was determined at week (W)4 and W8. Impact of ITPA deficiency on anaemia, RBV Ctrough, response and haematotoxicity (grade 3/4 anaemia, erythropoietin [EPO] use, RBV dose reduction or transfusion between day [D]0 and W8) was evaluated. Impact of RBV Ctrough on anaemia…

Effect of 3rd-order aberrations on human vision

2007

To investigate the effect of 3rd-order aberrations on human vision.Grupo de Ciencias de la Visión, University of Murcia, Murcia, Spain.The 3rd-order aberrations coma and trefoil were induced with purpose-designed soft contact lenses, 3 inducing coma (low [0.05 microm], medium [0.13 microm], high [1.03 microm]) and 3 inducing trefoil (low [0.07 microm], medium [0.17 microm], high [0.96 microm]). Monocular high-contrast (HCVA) and low-contrast (LCVA) visual acuities and contrast sensitivity were measured in 11 subjects wearing contact lenses with a 5.0 mm artificial pupil.The reduction in HCVA and LCVA was statistically significant only for the highest coma and trefoil values (P.0001). For co…

Accounting for Input Noise in Gaussian Process Parameter Retrieval

2020

Gaussian processes (GPs) are a class of Kernel methods that have shown to be very useful in geoscience and remote sensing applications for parameter retrieval, model inversion, and emulation. They are widely used because they are simple, flexible, and provide accurate estimates. GPs are based on a Bayesian statistical framework which provides a posterior probability function for each estimation. Therefore, besides the usual prediction (given in this case by the mean function), GPs come equipped with the possibility to obtain a predictive variance (i.e., error bars, confidence intervals) for each prediction. Unfortunately, the GP formulation usually assumes that there is no noise in the inpu…

Tipología de los errores en el cálculo mental : un estudio en el contexto educativo

1995

Resumen basado en el de la publicación Resumen en inglés Se aborda una tipología de errores y dificultades de los estudiantes españoles de un Colegio de Formación de Profesores cuando aplican métodos históricos de cálculo mental (métodos tomados de la tradición escrita que se encuentra en la aritmética) de los libros de texto para resolver problemas con números naturales y con números decimales. ESP

Numerical scheme influence on Pseudo Dynamic tests results

2008

Sample-size calculation and reestimation for a semiparametric analysis of recurrent event data taking robust standard errors into account

2014

In some clinical trials, the repeated occurrence of the same type of event is of primary interest and the Andersen-Gill model has been proposed to analyze recurrent event data. Existing methods to determine the required sample size for an Andersen-Gill analysis rely on the strong assumption that all heterogeneity in the individuals' risk to experience events can be explained by known covariates. In practice, however, this assumption might be violated due to unknown or unmeasured covariates affecting the time to events. In these situations, the use of a robust variance estimate in calculating the test statistic is highly recommended to assure the type I error rate, but this will in turn decr…

A systematic analysis of duplicate records in Scopus

2015

In recent years, the Web of Science Core Collection and Scopus databases have become primary sources for conducting studies that evaluate scientific investigations. Such studies require that duplicate records be excluded to avoid errors of overrepresentation. In this line, we identify duplicate records in Scopus and examine their origins. Identifying journals with duplicate records in Scopus, selecting and downloading bibliographic journal records, and identifying and analyzing the duplicate records is the methodology adopted. Duplicate records are found when articles published in a journal are incorrectly mapped by Scopus to this journal and to a different journal from the same publisher a…