Search results for "Mathematical models"
showing 9 items of 39 documents
Modeling NAFLD Disease Burden in China, France, Germany, Italy, Japan, Spain, United Kingdom, and United States for the period 2016-2030
2018
Background & Aims: Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are increasingly a cause of cirrhosis and hepatocellular carcinoma globally. This burden is expected to increase as epidemics of obesity, diabetes and metabolic syndrome continue to grow. The goal of this analysis was to use a Markov model to forecast NAFLD disease burden using currently available data. Methods: A model was used to estimate NAFLD and NASH disease progression in eight countries based on data for adult prevalence of obesity and type 2 diabetes mellitus (DM). Published estimates and expert consensus were used to build and validate the model projections. Results: If obesity and…
Anemia management in end stage renal disease patients undergoing dialysis: a comprehensive approach through machine learning techniques and mathemati…
2016
Kidney impairment has global consequences in the organism homeostasis and a disorder like Chronic Kidney Disease (CKD) might eventually exacerbates into End Stage Renal Disease (ESRD) where a complete renal replacement therapy like dialysis is necessary. Dialysis partially reintegrates the blood ltration process; however, even when it is associated to a pharmacological therapy, this is not su fficient to completely replace the renal endocrine role and causes the development of common complications, like CKD secondary anemia (CKD-anemia) The availability of exogenous Erythropoiesis Stimulating Agents (ESA, synthetic molecules with similar structure and same mechanism of action as human eryth…
Modified Donnan phenomena in polyaniline with poly(vinyl sulphonate) chains
1993
We develop a physical model, based on the modified Donnan phenomena ideas introduced previously by the authors, to describe the acid doping of the conducting polymer polyaniline. The theory is motivated by the experimental work of Asturias et al. [Ber. Bunsenges. Phys. Chem. 95, 1381 (1991)]. Good agreement between theory and experiment is found.
Validity of a novel device for indoor analysis of cyclists' drag area
2021
Cyclists need to measure aerodynamic resistance accurately and reliably, as well as economically. Devices such as Notio Aerostick, an equipment device that includes one pitot tube, have appeared for this purpose. The aim of this study is, therefore, to test the reliability and degree of agreement in the evaluation of the CdA (coefficient of aerodynamic drag), assessed by means of the Notio Aerostick compared to the Virtual Elevation (VE) and Martin mathematical models.Seventeen professional cyclists rode in a 250-metre-long velodrome covered with a concrete surface with their own time trial bikes. Each cyclist completed three rides of 15 laps at constant speed for the evaluation of the CdA,…
Dangerous relationships : biases in freshwater bioassessment based on observed to expected ratios
2018
Copyright by the Ecological Society of America The ecological assessment of freshwaters is currently primarily based on biological communities and the reference condition approach (RCA). In the RCA, the communities in streams and lakes disturbed by humans are compared with communities in reference conditions with no or minimal anthropogenic influence. The currently favored rationale is using selected community metrics for which the expected values (E) for each site are typically estimated from environmental variables using a predictive model based on the reference data. The proportional differences between the observed values (O) and E are then derived, and the decision rules for status ass…
Chaos and its Degradation-Promoting-Based Control in an Antithetic Integral Feedback Circuit
2022
This letter deals with a novel variant of antithetic integral feedback controller (AIFC) motifs which can feature robust perfect adaptation, a pervasive (desired) ability in natural (synthetic) biomolecular circuits, when coupled with a wide class of process networks to be regulated. Using the separation of timescales in the proposed kind of AIFC, here we find a reducedorder controller that captures the governing slow part of the original solutions under suitable assumptions. Inspired by R(ossler systems, we then make use of such a simpler controller to show that the antithetic circuit can exhibit chaotic behaviors with strange attractors, where the bifurcation from a homeostatic state to c…
Students' understanding of mathematical models in three norwegian biology courses
2018
International audience; Development in Biology over the last three decades have greatly increased the need for using mathematics in this field. This has influenced biology students which need to develop mathematical knowledge to be able to work with contemporary biology models, including frameworks that are applicable in analyzing the overwhelming flow of biological data (i.e. Labov, Reid & Yamamoto, 2010). Although a quantitative approach is often used in university biology courses, yet they remain largely qualitative and descriptive (Nelson, et. al., 2009). In Norwegian context, where this study will be conducted, there is an increased awareness towards mathematics from the Departments of…
On the volumetric response of a compacted clay subjected to wetting and drying cycles
2009
Experimental evidence on the volumetric response of a compacted clay was collected in controlled suction oedometric tests, with the aim to assess the volumetric response of this soil when subjected to wetting and drying cycles. The overall soil behaviour seems mainly to depend on the double structural arrangement observed in the compacted specimens. Selected results are presented and discussed focusing on the influence of the stress history on the volumetric response. Test results are simulated by a double-structure suction-dependent elasto-plastic constitutive model, in which the mechanical response is related to micro and macrostructural deformations and their mutual interactions. The pro…
Organizational Wellness Modeling
2009
The aim of the present paper is to establish certain mathematical models for organizational wellness as well as to create some wellness optimization problems applicable to any type of organization (including universities) that might be mathematically solved resorting to aspects of operational research of mathematical analysis. The results obtained associated with a mathematical apparatus enable one to perform analyses, comparisons, interpretations, predictions. All of us have, consciously or not, a genuine curiosity in creating and shaping organizational wellness. This concept represents a highly topical issue since professional activity, irrespective of its field, holds a very significant …