Search results for "theoretical model"
showing 10 items of 107 documents
Microcalorimeter/EBIT measurements of X-ray spectra of highly charged ions
2001
Spectra of highly charged Ar, Kr, Xe and Fe ions, produced in an Electron Beam Ion Trap (EBIT), have been recorded in a broad X-ray energy band (0.2 keV to 10 keV) with a microcalorimeter detector. The first analysis of the Kr spectra has been completed and most of the spectral lines have been identified as transitions of B- to Al-like Kr. Line intensity ratios of Fe XVII have been measured and compared with theoretical models.
Predicting limiting 'free sugar' consumption using an integrated model of health behavior.
2020
Excess intake of ‘free sugars’ is a key predictor of chronic disease, obesity, and dental ill health. Given the importance of determining modifiable predictors of free sugar-related dietary behaviors, we applied the integrated behavior change model to predict free sugar limiting behaviors. The model includes constructs representing ‘reasoned’ or deliberative processes that lead to action (e.g., social cognition constructs, intentions), and constructs representing ‘non-conscious’ or implicit processes (e.g., implicit attitudes, behavioral automaticity) as predictors of behavior. Undergraduate students (N = 205) completed measures of autonomous and controlled motivation, the theory of planned…
Hydrodynamic chromatography of macromolecules on 2 μm non-porous spherical silica gel packings
1989
Non-porous spherical 2μm silica gel particles have been tested as packing for hydrodynamic chromatography of macromolecules (HDC). Columns packed with these particles in 250×4.6mm i.d. columns can be operated very efficiently (e.g. a reduced plate height of about 2) when the detection cell is miniaturized. The packing is suitable for the separation of polystyrenes of Mw of 104–107 by hydrodynamic chromatography and the retention behaviour of polystyrenes agrees well with the known theoretical models. Preliminary results on the applicability of HDC for the separation of biopolymers are presented.
Numerical Simulations of Jets from Active Galactic Nuclei
2019
Numerical simulations have been playing a crucial role in the understanding of jets from active galactic nuclei (AGN) since the advent of the first theoretical models for the inflation of giant double radio galaxies by continuous injection in the late 1970s. In the almost four decades of numerical jet research, the complexity and physical detail of simulations, based mainly on a hydrodynamical/magneto-hydrodynamical description of the jet plasma, have been increasing with the pace of the advance in theoretical models, computational tools and numerical methods. The present review summarizes the status of the numerical simulations of jets from AGNs, from the formation region in the neighborho…
Theoretical space-time modelling of the diffusion of raw materials and manufactured objects
2013
International audience; Workgroup 3 of ArchaeDyn II programme focuses its study on the diffusion systems of ancient products. In order to be able to structure data in GIS in an appropriate way, we propose a general theoretical modelling integrating the different components of the diffusion systems, and identifying their interactions and the factors affecting the location of products and their transfers. Three dimensions are considered: the Time, the Space and the Function of places. A product's pathway can be apprehended efficiently by distinguishing spatial entities as well as functional entities. This modelling highlights the fact that the approach through the simple notion of "site" is n…
Observation of the decay KL → πoγγ and of a form factor enhancement in the decay KL → e+e−γ
1991
Abstract The rare decay mode K L → o γγ has been observed in an experiment of the NA31 collaboration at CERN. From a signal of 21 events with a background of 1.5 ± 0.9 events, a branching ratio of (2.1 ± 0.6)10 −6 is calculated for decays with an invariant γγ mass above 280 MeV. This result is compared with the values estimated from theoretical models and has implications for the CP-conserving contribution to K L → π o e + e − decay. In the same experiment, 1053 decays of the type K L → e + e − γ were observed. The branching ratio is measured to be (9.2 ± 0.5 ± 0.5)10 −6 in good agreement with theoretical expectations. An enhancement is observed at high masses in the distribution of the inv…
Sex-role orientation and memory for gender-related terms: Another uncertain link
1989
Two studies are reported which investigate the relationship between sex-role orientation and memory for gender-related terms. Based on the concept of ‘cognitive schema’, theoretical models have recently been advanced suggesting that the schematic cognitive representation of gender facilitates the recall of words pertinent to gender. One of these models, Markus' self-schema theory, proposes that masculine and feminine sex-typed individuals have a better memory for terms that correspond to their respective self-schemata. In contrast, Bem's gender schema theory implies that sex-typed individuals have a better memory for the category of gender as a whole, i.e. for both masculine and feminine te…
Threshold cointegration and nonlinear adjustment between stock prices and dividends
2008
According to several empirical studies, the linear present-value model fails to explain the behaviour of stock prices in the long run. We analyse the possible presence of threshold cointegration between real stock prices and dividends for the US market during the period from 1871:1 to 2004:6. According to our results, the null hypothesis of linear cointegration between stock prices and dividends is rejected in favour of a two-regime threshold cointegration model. We find also that stock prices do not respond to equilibrium error, and dividends respond to the past divergence only if the deviation from the equilibrium error does not exceed the estimated threshold parameter. This in turn would…
The diffusion and influence of theoretical models of information behaviour : the case of Savolainen's ELIS model
2020
PurposeTo ascertain the diffusion and influence of Savolainen's ELIS model and its use as a theoretical and/or methodological basis for research.Design/methodology/approachA context citation analysis was made of the work where this researcher published his model. Analysis covered the year of publication, the type of work and the subject matter of the citing documents concerned. In-context citations were analysed for their frequency in each citing text, style, location and content cited.FindingsThe ELIS model received 18.5 cites/year. 20.2 per cent of them corresponded to papers published in journals in other areas, mainly computer science. The average of cites per paper was 1.8; 64.5 percen…
Helical Shift Mechanics of Rubber V-Belt Variators
2011
A very common configuration of V-belt variators for motorcycles considers the correction of the belt tensioning depending on the resistant torque by means of suitable helical-shaped tracks allowing the driven half-pulleys to close/open. The theoretical model for belt-pulley coupling is rather complex for this configuration, where one half-pulley may run in advance and the other one behind with respect to the belt, and requires the repeated numerical solution of a strongly nonlinear differential system by a sort of shooting technique, until all the operating conditions are fulfilled (angular contact extent, torque, and axial force). After solving the full equations, the present study develop…