Search results for "Likelihood ratio"
showing 10 items of 30 documents
IFN-gamma-induced protein 10 is a novel biomarker of rhinovirus-induced asthma exacerbations
2007
BACKGROUND: Rhinovirus-induced acute asthma is the most frequent trigger for asthma exacerbations. OBJECTIVE: We assessed which inflammatory mediators were released from bronchial epithelial cells (BECs) after infection with rhinovirus and then determined whether they were also present in subjects with acute virus-induced asthma, with the aim to identify a biomarker or biomarkers for acute virus-induced asthma. METHODS: BECs were obtained from bronchial brushings of steroid-naive asthmatic subjects and healthy nonatopic control subjects. Cells were infected with rhinovirus 16. Inflammatory mediators were measured by means of flow cytometry with a cytometric bead array. Subjects with acute a…
The “ThreePlusOne” Likelihood-Based Test Statistics: Unified Geometrical and Graphical Interpretations
2014
The presentation of the well known Likelihood Ratio, Wald and Score test statistics in textbooks appears to lack a unified graphical and geometrical interpretation. We present two simple graphical representations on a common scale for these three test statistics, and also the recently proposed Gradient test statistic. These unified graphical displays may favour better understanding of the geometrical meaning of the likelihood based statistics and provide useful insights into their connections.
Stochastic ordering of classical discrete distributions
2010
For several pairs $(P,Q)$ of classical distributions on $\N_0$, we show that their stochastic ordering $P\leq_{st} Q$ can be characterized by their extreme tail ordering equivalent to $ P(\{k_\ast \})/Q(\{k_\ast\}) \le 1 \le \lim_{k\to k^\ast} P(\{k\})/Q(\{k\})$, with $k_\ast$ and $k^\ast$ denoting the minimum and the supremum of the support of $P+Q$, and with the limit to be read as $P(\{k^\ast\})/Q(\{k^\ast\})$ for $k^\ast$ finite. This includes in particular all pairs where $P$ and $Q$ are both binomial ($b_{n_1,p_1} \leq_{st} b_{n_2,p_2}$ if and only if $n_1\le n_2$ and $(1-p_1)^{n_1}\ge(1-p_2)^{n_2}$, or $p_1=0$), both negative binomial ($b^-_{r_1,p_1}\leq_{st} b^-_{r_2,p_2}$ if and on…
El viaje desde los cuestionarios Likert a los cuestionarios de elección forzosa: evidencia de la invarianza de los parámetros de los ítems
2019
ABSTRACT Multidimensional forced-choice questionnaires are widely regarded in the personnel selection literature for their ability to control response biases. Recently developed IRT models usually rely on the assumption that item parameters remain invariant when they are paired in forced-choice blocks, without giving it much consideration. This study aims to test this assumption empirically on the MUPP-2PL model, comparing the parameter estimates of the forced-choice format to their graded-scale equivalent on a Big Five personality instrument. The assumption was found to hold reasonably well, especially for the discrimination parameters. In the cases in which it was violated, we briefly dis…
Hypothesis testing for Panels of Semi-Markov Processes with parametric sojourn time distributions
2022
This work deals with the asymptotic properties of maximum likelihood estimators for semi-Markov processes with parametric sojourn time distributions. It is motivated by the comparison, via a two-sample test procedure, of the distribution of two panels of qualitative trajectories modeled by semi-Markov processes and observed over a random number of transitions. Considering first one panel of growing size, we derive, under classical conditions, the convergence in probability of the estimators of the transition probabilities and the parameters of the sojourn time distributions as well as their asymptotic normality. We then consider panels of semi-Markov processes drawn from two different popul…
Real-Time Detection of Incipient Inter-Turn Short Circuit and Sensor Faults in Permanent Magnet Synchronous Motor Drives Based on Generalized Likelih…
2022
This paper presents a robust model-based technique to detect multiple faults in permanent magnet synchronous motors (PMSMs), namely inter-turn short circuit (ITSC) and encoder faults. The proposed model is based on a structural analysis, which uses the dynamic mathematical model of a PMSM in an abc frame to evaluate the system’s structural model in matrix form. The just-determined and over-determined parts of the system are separated by a Dulmage–Mendelsohn decomposition tool. Subsequently, the analytical redundant relations obtained using the over-determined part of the system are used to form smaller redundant testable sub-models based on the number of defined fault terms. Furthermore, fo…
Global validation of the WSES Sepsis Severity Score for patients with complicated intra-abdominal infections : a prospective multicentre study (WISS …
2015
BACKGROUND: To validate a new practical Sepsis Severity Score for patients with complicated intra-abdominal infections (cIAIs) including the clinical conditions at the admission (severe sepsis/septic shock), the origin of the cIAIs, the delay in source control, the setting of acquisition and any risk factors such as age and immunosuppression. ----- METHODS: The WISS study (WSES cIAIs Score Study) is a multicenter observational study underwent in 132 medical institutions worldwide during a four-month study period (October 2014-February 2015). Four thousand five hundred thirty-three patients with a mean age of 51.2 years (range 18-99) were enrolled in the WISS study. ----- RESULTS: Univariate…
The new criteria for classification of rheumatoid arthritis: what we need to know for clinical practice.
2011
The new criteria for classification of Rheumatoid Arthritis have been recently released. They incorporate the anti-Citrullinated Protein antibody testing and the other classic criteria in a score system (the diagnosis of definite rheumatoid arthritis is made by a total score ≥6). These criteria try to meet the pressing needs to gain sensitivity in early disease. Symptoms, elevated acute-phase response, serologic abnormality, joint involvement were all considered for scoring after confirming the presence of synovitis in at least 1 joint in the absence of an alternative diagnosis that better explains the synovitis. However, no sensitivity and specificity has been showed. Moreover, Area Under …
Fatty liver indexandhepatic steatosis index for prediction ofnon-alcoholic fatty liver disease in type 1 diabetes
2017
Background and Aim Little is known about the diagnostic value of hepatic steatosis index (HSI) and fatty liver index (FLI), as well as their link to metabolic syndrome in type 1 diabetes mellitus. We have screened the effectiveness of FLI and HSI in an observational pilot study of 40 patients with type 1 diabetes. Methods FLI and HSI were calculated for 201 patients with type 1 diabetes. Forty patients with FLI/HSI values corresponding to different risk of liver steatosis were invited for liver magnetic resonance study. In-phase/opposed-phase technique of magnetic resonance was used. Accuracy of indices was assessed from the area under the receiver operating characteristic curve. Results Tw…
The challenge of using the rheumatoid arthritis diagnostic criteria in clinical practice.
2015
The new 2010 ACR/EULAR (American College of Rheumatology/European League Against Rheumatism) criteria of Rheumatoid Arthritis recently published, have been released to classify and identify patients with early RA who could benefit from early therapy. They recommend anti-citrullinated protein antibody (ACPA) testing as an alternative criterion to Rheumatoid Factor (RF) and ACPA that were introduced together with the other classic criteria in a scoring system. We previously criticized these new criteria because of unavailable specificity and sensibility in the first paper, and the use of ACPA as dichotomous criterion (presence/absent) and alternatives to rheumatoid factor. Our previous work p…