scholarly journals Estimation of Daily Reproduction rates in COVID-19 Outbreak

2021 ◽  
Author(s):  
Jacques Demongeot ◽  
Kayode Oshinubi ◽  
Hervé Seligmann ◽  
Florence Thuderoz
Keyword(s):  
Infectious Agent ◽  
Discrete Dynamics ◽  
Forecasting Methods ◽  
Simulation Results

Abstract(1) BackgroundThe estimation of daily reproduction rates throughout the infectivity period is rarely considered and only their sum Ro is calculated to quantify the level of virulence of an infectious agent;(2) MethodsWe give the equation of the discrete dynamics of epidemic growth and we obtain an estimation of the daily reproduction rates, by using a technique of deconvolution of the series of observed new cases of Covid-19;(3) ResultsWe give both simulation results as well as estimations for several countries for the Covid-19 outbreak;(4) ConclusionsWe discuss the role of the noise on the precision of the estimation and we open on perspectives of forecasting methods to predict the distribution of daily reproduction rates along the infectivity period.

scholarly journals Estimation of Daily Reproduction Numbers during the COVID-19 Outbreak

Computation ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 109
Author(s):  
Jacques Demongeot ◽  
Kayode Oshinubi ◽  
Mustapha Rachdi ◽  
Hervé Seligmann ◽  
Florence Thuderoz ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Discrete Dynamics ◽  
Host Age ◽  
Age Classes ◽  
Reproduction Numbers ◽  
Deconvolution Technique ◽  
Simulation Results ◽  
The Stability

(1) Background: The estimation of daily reproduction numbers throughout the contagiousness period is rarely considered, and only their sum R0 is calculated to quantify the contagiousness level of an infectious disease. (2) Methods: We provide the equation of the discrete dynamics of the epidemic’s growth and obtain an estimation of the daily reproduction numbers by using a deconvolution technique on a series of new COVID-19 cases. (3) Results: We provide both simulation results and estimations for several countries and waves of the COVID-19 outbreak. (4) Discussion: We discuss the role of noise on the stability of the epidemic’s dynamics. (5) Conclusions: We consider the possibility of improving the estimation of the distribution of daily reproduction numbers during the contagiousness period by taking into account the heterogeneity due to several host age classes.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Technique of scientific and technical forecasting using neural networks

2018 ◽  
pp. 103-110
Author(s):  
V. V. Nefedev
Keyword(s):  
Mathematical Modeling ◽  
Neural Networks ◽  
Artificial Neural Networks ◽  
Original Method ◽  
Forecasting Methods ◽  
Expert Assessments ◽  
Artificial Neural

For the definition and implementation of breakthrough technologies the most important is the role of scientific and technical forecasting. Well-known forecasting methods based on extrapolation, expert assessments and mathematical modeling are not universal and have a number of significant disadvantages. The article proposes an original method of scientific and technical forecasting based on the use of the methodology of artificial neural networks. 

scholarly journals EFFECT OF EXTRACHROMOSOMAL ELEMENTS OF HEREDITY ON TOXIC PROPERTIES OF YERSINIA PESTIS

2017 ◽  
pp. 28-33 ◽  
Author(s):  
G. V. Demidova ◽  
E. P. Sokolova ◽  
V. P. Zyuzina ◽  
V. A. Rykova ◽  
I. V. Morozova ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Active Form ◽  
Infectious Agent ◽  
Toxic Shock ◽  
Toxic Activity ◽  
Virulent Strains ◽  
Extrachromosomal Elements ◽  
Live Bacteria ◽  
First Time

Aim. Elucidation of the role of extrachromosomal elements of heredity in manifestations of toxic properties of Yersinia pestis. Materials and methods. The study was carried out in vaccine strain Y. pestis EV76 (pMTl, pCDl, pPCPl) and non-plasmid variants of vaccine EV76 (pMTl\ pCDl', pPCPl') and virulent 231 (рМТГ, pCDl’, pPCPl') strains of Y. pestis. Presence of functionally active form of lipopolysaccharide (LPS) in the incubation medium of the bacteria was evaluated via toxicity of supernatant of Y. pestis for intact animals (infection-toxic shock) and mice sensitized by D-GalN. Results. 37°C cultures of Y. pestis EV76 containing a full amount of plasmids were established to release LPS into the environment. Non-plasmid variants of both vaccine and virulent strains of Y. pestis pMTl', pCD Г, рРСР 1 do not have this ability. Separation of LPS from cell wall was detected in live bacteria of plague infectious agent. This process is assumed to be coupled with translocation of proteins coded by pMTl, pCDl, pPCPl plasmids from the cell into the environment. Conclusion. Functional interconnection between extrachromosomal elements of heredity and toxic activity of Y. pestis LPS is established for the first time.

scholarly journals Biological role of zonulin: a biomarker of increased intestinal permeability syndrome

2021 ◽  
Vol 66 (1) ◽  
pp. 31-38
Author(s):  
A. I. Khavkin ◽  
N. M. Bogdanova ◽  
V. P. Novikova
Keyword(s):  
Digestive Tract ◽  
Intestinal Microbiota ◽  
Intestinal Mucosa ◽  
Inflammatory Process ◽  
Biological Rhythms ◽  
Infectious Agent ◽  
Biological Role ◽  
Pathological Conditions ◽  
Intercellular Connections

.Both changes in diet and pathological conditions caused by an infectious agent, allergic or autoimmune inflammatory process, affect the biological rhythms of the digestive tract, which negatively affects the intestinal microbiota and increases the permeability of the intestinal mucosa. The altered microbiota potentiates inflammation and causes a “vicious circle”. The zonulin protein is the agent that modulates the density of intercellular connections. The review presents data on the biological role of zonulin, correction of its synthesis violation with the help of functional products for baby food.

Endogenous Uncertainty and the Dynamics of Constraints

2019 ◽  
pp. 246-260
Author(s):  
Paul Humphreys
Keyword(s):  
Utility Maximization ◽  
Social Dynamics ◽  
Fitness Landscape ◽  
Agent Based Model ◽  
Agent Based ◽  
Endogenous Uncertainty ◽  
The Commons ◽  
Simulation Results ◽  
Special Case

An agent- based model of social dynamics is introduced using a deformable fitness landscape, and it is shown that in certain clearly specifiable situations, strategies that are different from utility maximization outperform utility maximizers. Simulation results are presented and intuitive interpretations of the results provided. The situations considered occur when individuals' actions affect the outcomes for other agents and endogenous effects are dominant. The Tragedy of the Commons is merely a special case of this. Arguments are given that constraints are to be encouraged in some circumstances. The appropriate role of constraints in various types of society is assessed and their use justified in identifiable types of situations.

Theoretical analysis of LC-refining – pressure screening systems in TMP

2019 ◽  
Vol 34 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Jorge Enrique Rubiano Berna ◽  
Christer Sandberg ◽  
Mark Martinez ◽  
James Olson
Keyword(s):  
Fibre Length ◽  
Performance Curves ◽  
Average Fibre ◽  
Mechanical Pulps ◽  
Simulation Results ◽  
Save Energy ◽  
Relative Errors ◽  
The Impact ◽  
Screening Systems

Abstract LC refining of mechanical pulps has proven to save energy in the production of TMP pulps. However, the specific role of LC refining as part of a TMP system has not been thoroughly studied since it is difficult to conceive any particular system at industrial-scales and impractical at pilot-scales. In this study, pressure screening and LC refining models that describe fibre length distributions, together with correlations to predict refining power were used to model three basic refining systems. From the simulation results, the impact of important variables such as reject ratio, refiner gap and refining net-power was studied. Performance curves of length-weighed average fibre length were generated from simulation results and were used to assess each system behaviour and also to make comparisons between systems. Data from an industrial scale TMP mill sub-system was gathered and compared to simulation results showing relative errors between 0–18 % on the predicted variables.

Prions: Protein Aggregation and Infectious Diseases

2009 ◽  
Vol 89 (4) ◽  
pp. 1105-1152 ◽  
Author(s):  
Adriano Aguzzi ◽  
Anna Maria Calella
Keyword(s):  
Protein Aggregation ◽  
Prion Diseases ◽  
Physiological Role ◽  
Infectious Agent ◽  
Normal Function ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Pathological Features ◽  
Spongiform Encephalopathies

Transmissible spongiform encephalopathies (TSEs) are inevitably lethal neurodegenerative diseases that affect humans and a large variety of animals. The infectious agent responsible for TSEs is the prion, an abnormally folded and aggregated protein that propagates itself by imposing its conformation onto the cellular prion protein (PrPC) of the host. PrPCis necessary for prion replication and for prion-induced neurodegeneration, yet the proximal causes of neuronal injury and death are still poorly understood. Prion toxicity may arise from the interference with the normal function of PrPC, and therefore, understanding the physiological role of PrPCmay help to clarify the mechanism underlying prion diseases. Here we discuss the evolution of the prion concept and how prion-like mechanisms may apply to other protein aggregation diseases. We describe the clinical and the pathological features of the prion diseases in human and animals, the events occurring during neuroinvasion, and the possible scenarios underlying brain damage. Finally, we discuss potential antiprion therapies and current developments in the realm of prion diagnostics.

scholarly journals Numerical Simulation of A Cubic Spout-Fluid Bed: Influences of Inlet Gas Temperature and Jet to Bed Cross-Section Ratio

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Ali Rahmani ◽  
Mohsen Tamtaji ◽  
Asghar Molaei Dehkordi
Keyword(s):  
Cross Section ◽  
Circulation Pattern ◽  
Particle Simulation ◽  
Cross Section Ratio ◽  
Gas Temperature ◽  
Section Ratio ◽  
Fluid Bed ◽  
Discrete Particle Simulation ◽  
Simulation Results

AbstractIn this paper, we study the role of inlet gas temperature and jet to bed cross-section ratio on hydrodynamics and circulation patterns of particles in a spout-fluid bed. The system is modeled using CFD-TFM approach based on Eulerian-Eulerian method. Simulation results are validated by experimental data measured by (Link 2008. “PEPT and Discrete Particle Simulation Study of Spout-fluid Bed Regimes.” Aiche Journal 54 (5): 1189–202). First, the sensitivity analysis of simulation results versus the most significant parameters are conducted to find the optimum values for each parameter. Subsequently, the role of inlet gas temperature and cross-section ratios are studied in detail. The simulation results clearly demonstrate that increasing the inlet gas temperature raises particles’ velocity in the bed and affects the circulation pattern in annulus region. Additionally, it is shown that higher gas temperature leads to existence of hot spots in the annulus region. In case of jet to bed cross-section ratio, using larger ratios results in higher velocities and lower pressure drop along the bed.

scholarly journals Academic-industry partnerships in addressing nutrition – [Infection-immunity-inflammation] interactions

2007 ◽  
Vol 98 (S1) ◽  
pp. S17-S23 ◽  
Author(s):  
Ricardo Uauy
Keyword(s):  
Cell Injury ◽  
Tissue Injury ◽  
Infectious Agent ◽  
Nutritional Supplement ◽  
Novel Foods ◽  
Protein Energy ◽  
Toxic Damage ◽  
Inflammatory Processes ◽  
The Impact

The interaction between nutrition and infection is a key determinant of human health. Traditionally the interaction has centered on the role of nutrients in defining host defenses and the impact of infection in defining nutritional needs and status. Over the past decades the interaction has expanded its scope to encompass the role of specific nutrients in defining acquired immune function, in the modulation of inflammatory processes and on the virulence of the infectious agent itself. More recently the role of micronutrients and fatty acids on the response of cells and tissues to hypoxic and toxic damage has been recognized suggesting a fourth dimension to the interaction. The list of nutrients affecting infection, immunity, inflammation and cell injury has expanded from traditional protein-energy supply to several vitamins, multiple minerals and more recently specific lipid components of the diet. The promise of nutrition in the defense against infection, inflammation and tissue injury has spawned a thriving pharma-nutritional supplement industry and the development of novel foods that require appropriate evaluation of efficacy, safety and effectiveness relative to costs. Academics need to aware of the ethics and the pitfalls in the interaction with industry; conversely industry has to define its role in the process of bringing new knowledge to useful products. The process needs to be interactive, transparent and clearly place public interest above all other considerations.

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