Search results for "structural"
showing 10 items of 5047 documents
Dioxomolybdenum(VI) and -Tungsten(VI) Amino Bisphenolates as Epoxidation Catalysts
2016
Low-cost metallate salts Na2MO4·2H2O (M = molybdenum, tungsten) react with a tridentate amine bisphenol bis(2-hydroxy-3-tert-butyl-5-methylbenzyl)methylamine (H2ONOtBu) under ambient conditions in acidic methanol solutions. The reactions lead to the formation of isostructural dioxo complexes [MO2(ONOtBu)(MeOH)]·MeOH in convenient yields. Spectral data as well as X-ray analyses reveal these complexes to be isostructural. Both compounds were tested as catalysts for epoxidation of olefins using cis-cyclooctene, cyclohexene, norbornene and styrene as substrates and tert-butyl hydroperoxide and hydrogen peroxide as oxidants. The molybdenum complex catalyses selectively the oxidation of cis-cyclo…
Teacher emotional support in relation to social competence in preschool classrooms
2020
The present study aimed to investigate the associations between teachers’ observed emotional support and social competence among Finnish pre-schoolers (6-year-olds). The quality of emotional support was observed using the Classroom Assessment Scoring System Pre-K in 47 preschool classrooms twice across the preschool year. Teachers rated children’s social competence in autumn and again in spring, using the Multisource Assessment of Social Competence Scale (MASCS), which produced sum scores for cooperating skills, empathy, impulsivity, and disruptiveness. Consistent with the transactional model, we specified reciprocal (auto-regressive and cross-lagged) relationships within a Multilevel Struc…
Structural Composition of Protozooplankton Communities in Relation to Environmental Factors in Shallow Lakes and Reservoirs of Rīga, Latvia
2015
Abstract Protozooplankton are dominant grazers of phytoplankton and an important component of the microbial food web, as a link between pico and nanoplankton to higher trophic levels. Their fast growing rate, relative abundance, biomass and diversity are used as indicators of organic and toxic pollution. The impact of urbanisation on ecosystems and their sustainability and biodiversity have recently been much studied. We studied the protozooplankton ciliate communities during the vegetation period from April to October in two small lakes (Bābelītis, Gaiļezers) and two reservoirs (Bolderāja, Saurieši). The largest peak of biomass (15.7 × 102 mg/l) was found in Gaiļezers Lake in August and of…
IEA EBC Annex83 Positive Energy Districts
2021
At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challeng…
Explaining the Usage Intentions of Exergames
2014
Different kinds of digital gaming concepts that combine exercise and games, commonly referred to as exergames, have become increasingly common in recent years. These games, which can be used because of both hedonic and utilitarian reasons, have also become a subject of growing interest among academic researchers. However, the factors that explain their usage remain vaguely understood. This study aims to find out what kinds of factors explain the intentions to use exergames as part of one’s exercise. To do this, we first propose a new theoretical model for explaining the usage intentions of exergames and then empirically test this model by analyzing an online survey sample collected from 271…
¿Por qué los estudiantes de la Universidad Pedagógica ISFODOSU escogen la carrera de Educación?
2020
As part of research aimed at establishing the profiles of students of new entry at ISFODOSU, we include vocational variables to determine the most important motivations for the choice of career of the participants, as well as for the election of this university and opinion on its technological resources. The sample (No. 744) was chosen at random, proportionally among the Enclosures, Careers and Sex strata. First, we validate the FIT-Choice scale with two confirmatory factorial analyses. The 12 motivational factors showed a good level of fit (RMSEA .062; CFI .92 and TLI .901, as well as the 6 perceptual factors (RMSEA .062; CFI .944 and TLI .924). The reliability of the motivational factors …
Spanish Validation of the Flourishing Scale in the General Population
2017
Well-being research and its measurement have grown in the last two decades. The objective of this study was to adapt and validate the Flourishing Scale in a sample of Spanish adults. This was a cross-sectional study using a non-probabilistic sample of 999 Spanish general adult population participants. The psychometric properties of the scale were analysed from an exploratory and confirmatory perspective. Exploratory factor analysis showed a one-factor solution explaining 42.3% of the variance; an internal consistency of .846; temporal reliability correlation of .749; convergent validity with the Satisfaction with Life Scale of .521 and criterion validity with positive and negative affect (P…
Creating Implicit Measure Stimulus Sets Using a Multi-Step Piloting Method
2023
The effect of arbitrary stimulus selection is a persistent concern when employing implicit measures. The current study tests a data-driven multi-step procedure to create stimulus items using a combination of free-recall and survey data. Six sets of stimulus items were created, representing healthy food and high sugar items in children, adolescents, and adults. Selected items were highly representative of the target concepts, in frequent use, and of near equal length. Tests of the piloted items in two samples showed slightly higher implicit measure–behavior relations compared to a previously used measure, providing preliminary support for the value in empirically based stimulus selection. Fu…
Estudio de la deformidad del tejido cardiaco (strain) tras un infarto de miocardio con elevación del segmento ST mediante la técnica de resonancia ma…
2020
El presente trabajo, que se dividió en tres partes, ha sido destinado al estudio de la deformación del tejido cardiaco (strain) mediante resonancia magnética cardiaca (RMC) tras un infarto agudo de miocardio con elevación del segmento ST (IAMEST). Para ello se realizó un estudio de la caracterización, dinámica, implicación estructural y valor pronóstico de los diferentes índices de strain derivados de la RMC. La RMC se ha convertido en la última década en la técnica gold-standard para el estudio y la caracterización del tejido cardiaco después de sufrir un IAMEST. Durante los últimos años, el tissue tracking (TT) ha emergido cómo una técnica de imagen que permite evaluar de forma cuantitati…
Analysis of requirements for valve accuracy and repeatability in high efficiency digital displacement motors
2018
Traditional variable displacement piston machines achieve high efficiency when operating at high displacements, but struggle with poor efficiency at low displacements. The pistons are connected to high pressure and low pressure in conjunction with the output shaft position and the displacement is changed by changing the piston stroke, resulting in almost constant friction, leakage, and compressibility losses independent of displacement. In digital displacement machines, the rotary valve is replaced by two fast switching on/off valves connected to every cylinder. By controlling the fast switching on/off valves, the cylinders can be controlled individually and friction, leakage and compressib…