Search results for "modelling"

A Multivariate Age-Structured Stochastic Model with Immunization Strategies to Describe Bronchiolitis Dynamics

2021

Bronchiolitis has a high morbidity in children under 2 years old. Respiratory syncytial virus (RSV) is the most common pathogen causing the disease. At present, there is only a costly humanized monoclonal RSV-specific antibody to prevent RSV. However, different immunization strategies are being developed. Hence, evaluation and comparison of their impact is important for policymakers. The analysis of the disease with a Bayesian stochastic compartmental model provided an improved and more natural description of its dynamics. However, the consideration of different age groups is still needed, since disease transmission greatly varies with age. In this work, we propose a multivariate age-struct…

Transcatheter indirect mitral annuloplasty induces annular and left atrial remodelling in secondary mitral regurgitation

2020

Abstract Aims Mitral annuloplasty using the Carillon Mitral Contour System (CMCS) reduces secondary mitral regurgitation (SMR) and leads to reverse left ventricular remodelling. The aim of this study was to evaluate the effect of the CMCS on the mitral valve annulus (MA) and left atrial volume (LAV). Methods and results We retrospectively evaluated the data of all patients treated with the CMCS at our centre. Using transthoracic echocardiography, MA diameters were assessed by measuring the anterolateral to posteromedial extend (ALPM) and the anterior to posterior (AP) dimensions, respectively. Also, LAV and left ventricular end‐diastolic volume (LVEDV) were assessed. Patients were examined …

Modelling of mercury emissions from large solid fuel combustion and biomonitoring in Cz-Pl border region

2016

Tightening of norms for air protection leads to a development of new and significantly more effective techniques for removing particulate matter, SOx and NOx from flue gas which originates from large solid fuel combustion. Recently, it has been found that combinations of these environmental technologies can also lead to the reduction of mercury emissions from coal power plants. Now the greatest attention is paid especially to the coal power plant in Opatovice nad Labem, close to Hradec Kralove. Its system for flue gas dedusting was replaced by a modern type of cloth fabric filter with the highest particle separation efficiency which belongs to the category of BAT. Using this technology, tog…

Predicting stiffness and strength of birch pulp:Polylactic acid composites

2016

This paper studies failure of birch pulp–polylactic acid composites. Stiffness and strength are calculated using the theory of short fibre composites and the results are compared to experimental data. The results differed from the experimental values by 0–6%. With less aligned fibres the short fibre theory is not feasible. The performance of the 40 wt% birch pulp – polylactic acid composite is predicted with X-ray microtomography based finite element modelling, and the results are compared with experiments. Stiffness results differed from experiments by 1–17% . By adding into the models a third material phase representing the interface between the fibres and the matrix, the stress–strain c…

Quel statut pour les espaces de montagne durant l'âge du Bronze ? Regards croisés sur les approches société-environnement dans les Pyrénées occidenta…

2005

After having been neglected for some time, mountain environments have now become an important research area for the study of anthropogenic impact on the environment and the interactions of societies with their environments. The recent development of several interdisciplinary programs in the Alps and in the Pyrenees reveals the interest and the scientific questions associated with these domains. In the Pyrenees, the work undertaken in the Basque Country illustrates the utility of the development of multidisciplinary research on a large scale, which is both diachronic and has a high resolution chronology. Combining environmental and archaeological data, allows us to present an image of popula…

Modelling biological nitrogen and phosphorus removal with soluble microbial products (SMP) production-degradation processes

2011

Over the last two decades, Membrane Bioreactors (MBR) are increasingly used for wastewater treatment. Mathematical modelling of MBR systems has played a key role in order to better explain the effect of their peculiarities. Indeed, several MBR models have been presented in literature in order to improve the knowledge on MBR systems: biological models, hybrid models which include soluble microbial product (SMP) modelling, physical models able to describe the membrane fouling and integrated models which couple the hybrid models with the physical ones. However, among the existing MBR models only few integrated models have been developed which take into account the existing relationship between…

Bases metodológicas para el uso de la modelización en la enseñanza y comprensión de la dinámica litoral

2017

[EN] This paper proposes the use of modelling to improve the understanding of certain coastal environmentalproblems. In particular the methodological basis that was used to build a consensus teaching model, in-cluding environmental and human factors that determine the dynamics of coastal sediments, is included.The development of the consensus model had the collaboration of experts in coastal sedimentology andecosystems as well as teachers of di erent educational levels (from Primary to University), which helpedselect the ages to which the modelling could be applied, helping also in developing the graphical model thatwould be the base for a future educational intervention

Molecular Modelling Studies on Molecular Pathways Related to Tumorigenesis in the Discovery of New Lead Compounds.

2012

Integrated Urban Water Modeling with Uncertainty Analysis

2005

In the last 20th years, the scientific world has got particular care towards the problems that involve the respect of the environment. According to this point, several researches were developed to describe the phenomena that take place during both wet and dry period and to increase the knowledge in this field. In particular, the attention was addressed towards the problems linked with the pollution of the water body because of the pollution carried by rainfall waters in the urban environment. In order to obtain a good description of the problem, it is important, of course, to analyze both quantity and quality aspects connected with all the transformation phases that characterize the urban w…

Exploring grade 9 students' assumption making when mathematizing

2015

International audience; Making assumptions is a key activity in modelling. The present study aims to explore the variety of assumptions that lower secondary students make in this process. As theoretical basis for the data analysis, we used the modelling cycle by Blum and Leiss (2007) and framed a definition of assumptions. The study was carried out with grade 9 students. The results show three categories of assumptions: (1) parameter assumptions, (2) assumptions for the choice of the mathematical model, and (3) assumptions about task expectations. Assumptions from the first two categories assist students to use extra-mathematical knowledge to construct a mathematical model, while the third …