Search results for "upper"
showing 10 items of 987 documents
Defending either a personal or an assigned standpoint
2018
Abstract This study clarifies whether a specific type of role play supports upper secondary school students’ collaborative argumentation. Data consist of 12 dyadic face-to-face and 12 chat debates. Data analysis focused on the quality of students’ argumentation. Comparisons were made between students who defended standpoints at variance with their personal opinions on the topics, between the two study modes and topics, and by gender. When the students defended a standpoint differing from their personal opinion, the male students engaged in counterargumentation more often than the female students. When, in turn, the students defended their personal standpoint, they produced both counterargum…
Prevention of upper gastrointestinal bleeding from portal hypertension in cirrhosis: rationale for medical treatment.
1992
We updated meta-analysis and critical descriptive analysis of randomized clinical trials (RCTs) assessing the value of beta-blockers in preventing first bleeding (prophylactic) or rebleeding (therapeutic) and on survival of patients with cirrhosis. Both the methods of Peto-Mantel-Haenszel and DerSimonian-Laird were used to assess the heterogeneity and obtain cumulative estimates of treatment effects; the L'Abbé plot was also used for a visual assessment of heterogeneity in the direction of treatment effect. Seven prophylactic and nine therapeutic RCTs were analysed. beta-Blockers uniformly reduced the bleeding risk and revealed a trend toward improved survival in non-ascitic, well-compensat…
Immigrant status, gender, and school burnout in Finnish lower secondary school students : A longitudinal study
2017
The aim of this longitudinal study among 9223 students from grade 7 and grade 9 (age 13–14 and 15–16) was to assess whether immigrant status and gender are associated with the level and change (slope) in school burnout among lower secondary school students in the Helsinki metropolitan area. Ninety-seven percent of the variation in school burnout was attributable to individual factors. Both the intercept (2.3, p < 0.001) and slope (0.5, p < 0.001) of school burnout were statistically significant. The slope showed increasing school burnout from grades 7–9. School burnout increased more in girls than in boys. Initially apparent higher school burnout among students who had immigrated to …
Adaptive Neural Stabilizing Controller for a Class of Mismatched Uncertain Nonlinear Systems by State and Output Feedback
2015
In this paper, first, an adaptive neural network (NN) state-feedback controller for a class of nonlinear systems with mismatched uncertainties is proposed. By using a radial basis function NN (RBFNN), a bound of unknown nonlinear functions is approximated so that no information about the upper bound of mismatched uncertainties is required. Then, an observer-based adaptive controller based on RBFNN is designed to stabilize uncertain nonlinear systems with immeasurable states. The state-feedback and observer-based controllers are based on Lyapunov and strictly positive real-Lyapunov stability theory, respectively, and it is shown that the asymptotic convergence of the closed-loop system to ze…
Analytic Exact Upper Bound for the Lyapunov Dimension of the Shimizu–Morioka System
2015
In applied investigations, the invariance of the Lyapunov dimension under a diffeomorphism is often used. However, in the case of irregular linearization, this fact was not strictly considered in the classical works. In the present work, the invariance of the Lyapunov dimension under diffeomorphism is demonstrated in the general case. This fact is used to obtain the analytic exact upper bound of the Lyapunov dimension of an attractor of the Shimizu–Morioka system. peerReviewed
Adaptive neural state-feedback stabilizing controller for nonlinear systems with mismatched uncertainty
2014
In this paper, an adaptive neural network (NN) state-feedback controller for a class of nonlinear systems with mismatched uncertainties is presented. By using a radial basis (RBF) neural network, a bound of unknown nonlinear functions is approximated so that no information about the upper bound of mismatched uncertainties is required. The state-feedback is based on Lyapunov stability theory, and it is shown that the asymptotic convergence of the closed-loop system to zero is achieved while maintaining bounded states at the same time. The presented methods are more general than the previous approaches, handling systems with no restriction on the dimension of the system and the number of inpu…
How upper secondary students solve algebraic word problems in the area of mathematical modelling : A case study of one group of Norwegian students
2019
Masteroppgave matematikkdidaktikk MA500 - Universitetet i Agder 2019 For å imøtekomme nye utfordringer på skolen, i jobb og i livet, kan elever ha behov for åtilpasse og utvide den matematikken de kan. Dette krever at elever evner, i noen grad, åsette skolematematikken i forbindelse med hverdagslige kontekster og motsatt. Matema-tisk modellering er en av de hensiktsmessige mediene for å støtte sammenhengen mellomskolematematikken og virkeligheten. Forskning har vist at det er en sterk tilbøyelighet ipensumet mot matematisk modellering og at i stedet høynivå matematikk er ansett somviktig, mest på videregående nivå. Igjen, forskning viser at elever har større utfordringermed abstrakte (fakta…
Relevansen av trigonometri : En studie i to deler på relevansen av trigonometri for elever på videregående skole
2017
Masteroppgave matematikkdidaktikk MA502 – Universitetet i Agder 2017 The topic of this master’s thesis is the relevance of mathematics, especially the relevance of trigonometry. Many students ask the question “why do I need to learn about this”. The aim of this study was to give the students an answer to this question. In the research literature, I found that this question has to do with relevance, and that relevance is a connection between people, an activity and future goals. In particular, one needs to question: relevance of what? relevance according to whom? relevance for whom? And relevance to what end? The empirical part of my research consisted of two studies. In Study 1 the purpose …
The youngest Trigoniida (Mollusca, Bivalvia) of Europe, including new genera and species from the type area of the Maastrichtian Stage
2022
Until recently, only a single species of trigoniid bivalve was known from the upper Maastrichtian Maastricht Formation in the type area of the Maastrichtian Stage (south-east Netherlands and adjacent Belgian and German territories); it was named Trigonia maestrichtiana by Alphonse Briart in 1888. This common, rather small species is here transferred to the genus Oistotrigonia, and a lectotype is designated. In addition, two new genera of very small rutitrigoniids, Wolfgangella and Anniedhondtella, and three new species, W. neilpearti, W. ignota and A. rieui, are erected. Most of the material available is preserved as (paired) external and internal moulds in a nearshore facies of indurated b…
Profiles of multidrug-resistant organisms among patients with bacteremia in intensive care units: an international ID-IRI survey
2021
Evaluating trends in antibiotic resistance is a requisite. The study aimed to analyze the profile of multidrug-resistant organisms (MDROs) among hospitalized patients with bacteremia in intensive care units (ICUs) in a large geographical area. This is a 1-month cross-sectional survey for blood-borne pathogens in 57 ICUs from 24 countries with different income levels: lower-middle-income (LMI), upper-middle-income (UMI), and high-income (HI) countries. Multidrug-resistant (MDR), extensively drug-resistant (XDR), or pan-drug-resistant isolates were searched. Logistic regression analysis determined resistance predictors among MDROs. Community-acquired infections were comparable to hospital-acq…