Search results for "statistical [methods]"
showing 10 items of 1664 documents
Commentary: Psychological Science's Aversion to the Null
2017
Nuevas perspectivas sobre la detección de pediculosis activa en escolares del sur de Brasil
2021
The present study aims to analyze the prevalence and risk factors of active pediculosis and to compare the efficacy and sensitivity of the vacuum method with the comb method and the visual inspection with a magnifying glass in order to determine the best methodology to detect active pediculosis among schoolchildren from Paraná state. Each child was examined by the three methods in sequence and a playful activity was introduced to increase the children likelihood to participate in the study. Additionally, hair characteristics and other risk factors as sex, age, and area of living were take into consideration to measure epidemiological aspects. From a total of 358 schoolchildren from southern…
Efficacy of once-daily tiotropium Respimat in adults with asthma at GINA Steps 2-5.
2020
Tiotropium Respimat is an efficacious add-on to maintenance treatment in patients with symptomatic asthma. Currently, the Global Initiative for Asthma (GINA) strategy recommends tiotropium for patients at Steps 4–5. To assess the clinical benefits of tiotropium Respimat across asthma severities, GINA Steps 2–5, a post hoc analysis of five double-blind trials (12–48-weeks; patients aged 18–75 years) investigated the effect of tiotropium Respimat, 5 μg or 2.5 μg, versus placebo, on peak forced expiratory volume in 1 s (FEV1) within 3 h post-dose (FEV1(0–3h)) response, and Asthma Control Questionnaire-7 (ACQ-7) responder rate. GINA step grouping was based on patients’ background treatment regi…
Comparison of histological and computed tomographic measurements of pig lung bronchi.
2020
Aim Light microscopy is used as template in the evaluation and further development of medical imaging methods. Tissue shrinkage caused by histological processing is known to influence lung tissue dimensions. In diagnosis of COPD, computed tomography (CT) is widely used for automated airway measurement. The aim of this study was to compare histological and computed tomographic measurements of pig lung bronchi. Methods Airway measurements of pig lungs were performed after freezing under controlled inflation pressure in a liquid nitrogen bath. The wall thickness of seven bronchi was measured via Micro-CT and CT using the integral-based method (IBM) and the full-width-at-half-maximum method (FW…
Prognostic scoring system predictive of survival after surgical resection of esophageal carcinoma.
2013
BACKGROUND The aim of our study was to develop a prognostic index score for patients undergoing surgical resection for esophageal cancer that accurately determines survival with specific clinicopathological characteristics. METHODS Clinical, histological, and demographical variables of 475 patients were entered in an univariate and multivariate regression model, followed by individual calculation of the Prognostic Indicator Score and model validation via simulation. RESULTS Significant variables included in the scoring system were number of positive lymph nodes, pT, pL, R, obesity, and American Society of Anesthesiologist classification. Survival probability and its associated hazard functi…
A Noncommutative Approach to Ordinary Differential Equations
2005
We adapt ideas coming from Quantum Mechanics to develop a non-commutative strategy for the analysis of some systems of ordinary differential equations. We show that the solution of such a system can be described by an unbounded, self-adjoint and densely defined operator H which we call, in analogy with Quantum Mechanics, the Hamiltonian of the system. We discuss the role of H in the analysis of the integrals of motion of the system. Finally, we apply this approach to several examples.
Fractional Laplacians in bounded domains: Killed, reflected, censored, and taboo Lévy flights.
2018
The fractional Laplacian $(- \Delta)^{\alpha /2}$, $\alpha \in (0,2)$ has many equivalent (albeit formally different) realizations as a nonlocal generator of a family of $\alpha $-stable stochastic processes in $R^n$. On the other hand, if the process is to be restricted to a bounded domain, there are many inequivalent proposals for what a boundary-data respecting fractional Laplacian should actually be. This ambiguity holds true not only for each specific choice of the process behavior at the boundary (like e.g. absorbtion, reflection, conditioning or boundary taboos), but extends as well to its particular technical implementation (Dirchlet, Neumann, etc. problems). The inferred jump-type …
Tests of Independence Based on Sign and Rank Covariances
2003
In this paper three different concepts of bivariate sign and rank, namely marginal sign and rank, spatial sign and rank and affine equivariant sign and rank, are considered. The aim is to see whether these different sign and rank covariances can be used to construct tests for the hypothesis of independence. In some cases (spatial sign, affine equivariant sign and rank) an additional assumption on the symmetry of marginal distribution is needed. Limiting distributions of test statistics under the null hypothesis as well as under interesting sequences of contiguous alternatives are derived. Asymptotic relative efficiencies with respect to the regular correlation test are calculated and compar…
Functional renormalization group approach to the Kraichnan model.
2015
We study the anomalous scaling of the structure functions of a scalar field advected by a random Gaussian velocity field, the Kraichnan model, by means of Functional Renormalization Group techniques. We analyze the symmetries of the model and derive the leading correction to the structure functions considering the renormalization of composite operators and applying the operator product expansion.
Superstable cycles for antiferromagnetic Q-state Potts and three-site interaction Ising models on recursive lattices
2013
We consider the superstable cycles of the Q-state Potts (QSP) and the three-site interaction antiferromagnetic Ising (TSAI) models on recursive lattices. The rational mappings describing the models' statistical properties are obtained via the recurrence relation technique. We provide analytical solutions for the superstable cycles of the second order for both models. A particular attention is devoted to the period three window. Here we present an exact result for the third order superstable orbit for the QSP and a numerical solution for the TSAI model. Additionally, we point out a non-trivial connection between bifurcations and superstability: in some regions of parameters a superstable cyc…