Search results for "Linear relationship"
showing 9 items of 29 documents
Oral health-related quality of life of implant-supported overdentures versus conventional complete prostheses: Retrospective study of a cohort of ede…
2015
Background This work aims to confirm if implant-supported overdentures are a good treatment option for edentulous patients and offer an improvement in quality of life compared with traditional complete prostheses (dentures). Material and Methods This retrospective clinical descriptive study included three evaluation groups: validation group (n=57); control group of patients with complete removeable prostheses (n=56); study group of patients with implant-supported overdentures retained with the Locator® system (n=80). The study also validated the Oral Health Impact Profile-20 questionnaire. Individual protocols were created that included socio-demographic data, the Oral Health Impact Profile…
Parameters analysis of FitzHugh-Nagumo model for a reliable simulation
2014
International audience; Derived from the pioneer ionic Hodgkin-Huxley model and due to its simplicity and richness from a point view of nonlinear dynamics, the FitzHugh-Nagumo model has been one of the most successful neuron / cardiac cell model. It exists many variations of the original FHN model. Though these FHN type models help to enrich the dynamics of the FHN model. The parameters used in these models are often in biased conditions. The related results would be questionable. So, in this study, the aim is to find the parameter thresholds for one of the commonly used FHN model in order to pride a better simulation environment. The results showed at first that inappropriate time step and…
Ceftazidime Determination in Serum by High-pressure Liquid Chromatography
2004
A rapid and sensitive high-pressure liquid chromatographic method with simple sample preparation was developed for the quantitative analysis of the beta-lactam antibiotic ceftazidime (CAS 78439-06-2, Fortum). A good linear relationship was established between the peak area and the amount of ceftazidime injected over a concentration range of 1 to 200 microg/ml. The detection limit of the method was calculated to be 0.9 microg/ml. Stability was shown at 4 degrees C and at -196 degrees C for time periods of 2 h and 84 days, respectively.
Quasi-brittle porous material: Simulated effect of stochastic air void structure on compressive strength
2021
Abstract The effect of porosity comprised of spherical air voids on the compressive strength of quasi-brittle material was studied via simulations. The simulated porous structures were based on pore size distributions of two mortar samples measured by X-ray microtomography. While the simulation method set practical limits on the size of sample, the base of the statistics was established by simulating 128 small structures generated by sampling from pore structures of two mortars. By studying the application of the classical strength-porosity formulas to the simulated data, a new simple model was formed. A linear relationship was achieved between the cubic root of air void fraction (porosity)…
The Influence of Entrepreneurial Learning in New Firms’ Performance: A Study in Costa Rica
2014
The creation of new firms is important for the economy, and entrepreneurial learning is essential for the performance of new firms. We contribute to existing knowledge by combining these two topics and considering a third one: The role of multinational companies (MNCs) as a source of learning for the entrepreneur. This approach has rarely been taken in the literature. We investigated the performance of a group of young companies created by former employees of MNCs and their relationship with entrepreneurial learning in such companies. The study was based on a sample of 175 former employees of MNCs in Costa Rica, who founded their own firm between 2001 and 2007. The control group was formed …
Interval estimation for the breakpoint in segmented regression: a smoothed score-based approach
2017
Summary This paper is concerned with interval estimation for the breakpoint parameter in segmented regression. We present score-type confidence intervals derived from the score statistic itself and from the recently proposed gradient statistic. Due to lack of regularity conditions of the score, non-smoothness and non-monotonicity, naive application of the score-based statistics is unfeasible and we propose to exploit the smoothed score obtained via induced smoothing. We compare our proposals with the traditional methods based on the Wald and the likelihood ratio statistics via simulations and an analysis of a real dataset: results show that the smoothed score-like statistics perform in prac…
Grain size, stress and surface roughness
2008
In this article, we report molecular dynamics (MD) simulations on the formation of roughness at the surface of strained polycrystalline aluminum samples at 300 K. The computed roughness increases as a function of applied strain but does not follow a linear law for all applied strains. A linear relationship with a small slope is obtained in the elastic domain. Then, the roughness increases rapidly with the applied strain in the plastic domain studied. Moreover, the surface roughness increases as a function of grain size (between 5 and 20 nm) in the plastic domain (<6%).
Relationship between perception of malocclusion and the psychological impact of dental aesthetics in university students.
2014
Introduction and Objectives: The objectives were to assess the relationship between perceived smile aesthetics and perceived psychological impact as measured by the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ), and their own perception of it using the Aesthetic Component of the Index of Orthodontic Treatment Need (IOTN-AC) and a Visual Analog Scale (VAS); relate the IOTN-AC and VAS to the PIDAQ; and study the predictive capacity of the scales for psychological impact. Material and Methods: A cross-sectional study was conducted in 447 college students in Spain and Portugal (average age 20.4 years, 33.1% men and 66.9% women). The online self-completed surveys used the recent…
Fe-doped Beta zeolite from organotemplate-free synthesis for NH3-SCR of NOx
2016
Two types of Beta zeolites, one from organotemplate-free synthesis with a Si/Al ratio of 9 and the other from a commercial one with a Si/Al ratio of 19, were employed here to dope Fe for NH3-SCR of NOx. Fe-Beta (Si/Al = 9) exhibits much higher activity than Fe-Beta (Si/Al = 19), especially at low-temperature regions (<250 °C). In addition, it also exhibits better hydrothermal stability as compared with Fe-Beta (Si/Al = 19), which demonstrates that it is a promising SCR catalyst with good activity as well as hydrothermal stability. The correlation between the quantitative calculation of the content of isolated Fe3+ in Beta zeolites and the NO conversion rate at 150 °C shows a linear relation…