scholarly journals Building a modification of the SEIRD model of epidemic spread that takes into account the features of COVID-19

2020 ◽  
pp. 14-27
Author(s):  
Нина Игоревна Еремеева
Keyword(s):  
Mathematical Model ◽  
Relative Number ◽  
Rate Of Change ◽  
Distribution Model ◽  
Epidemic Spread ◽  
Infected People ◽  
The Moment ◽  
The Impact ◽  
The Relationship

Статья посвящена построению математической модели SEIIRDm, учитывающей некоторые особенности распространения COVID-19. Представляемая модель построена на основе классической SEIRD-модели распространения эпидемий. В созданной модели, в отличие от базовой, учитывается то, что латентные носители COVID-19 являются в некоторой степени заразными, и что у существенного количества инфицированных болезнь протекает бессимптомно. В SEIIRDm-модели отражен тот факт, что выявленные больные изолируются (госпитализируются) и вероятность заражения от них резко уменьшается, а также, что карантинные меры имеют массовый характер, причем важна как степень их жесткости, так и момент введения. Кроме того, в статье обращается внимание на то, что зависимость между скоростью изменения относительного числа заболевших и относительным количеством заразных и восприимчивых может быть нелинейной, и этот факт отражен в построенной модели. Статья содержит примеры численного прогнозирования развития эпидемиологического процесса, а также моделирования влияния массовых карантинных мер, рассчитанные на основе созданной математической модели. The article is devoted to the construction of a mathematical model that takes into account some features of COVID-19 propagation. The presented model is based on the classic SEIRD epidemic distribution model. The created model, in contrast to the basic one, takes into account the fact that latent COVIND-19 carriers are somewhat contagious and that in a significant number of infected people, the disease is asymptomatic. The SEIIRDm model reflects the fact that identified patients are isolating (hospitalizing) and the probability of infection from them decreases sharply and also that the measures taken over the quarantine are massive moreover, both the degree of their rigidity and the moment of introduction are important. Besides, the article draws attention to the fact that the relationship between the rate of change in the relative number of cases and susceptible and the relative number of infected may be nonlinear, and this fact is reflected in the built model. The article provides examples of numerical forecasting of the development of the epidemiological process as well as modeling the impact of mass quarantine measures, calculated on the basis of the created mathematical model.

scholarly journals Correlation of the epidemic spread of COVID-19 and urban population migration in the major cities of Hubei Province, China

2021 ◽  
Author(s):  
Qun Chen ◽  
Jiao Yan ◽  
Helai Huang ◽  
Xi Zhang
Keyword(s):  
Correlation Coefficient ◽  
Urban Population ◽  
Total Population ◽  
Hubei Province ◽  
Population Migration ◽  
Epidemic Spread ◽  
Weak Correlation ◽  
Infected People ◽  
The Impact ◽  
The Relationship

Abstract This study analyses the relationship between the epidemic spread of COVID-19 and urban population migration in Hubei Province, China. Based on an improved gravity model, the population inflow numbers for each city from 10 January to 23 February are estimated. A correlation analysis is done to reveal the impact of population inflow on the number of infected people in the 14 days after 23 January, the day Wuhan was locked down. The results show that: (i) the population outflow from Wuhan was mostly distributed between Xiaogan, Huanggang, Ezhou and Huangshi in Hubei Province; (ii) the number of accumulated confirmed patients is closely associated with inflows from Wuhan, which displayed by correlation coefficient 1 with a mean of 0.88 and a maximum of 0.93. Meanwhile, there is a weak correlation between the number of people that came from cities except Wuhan and accumulated confirmed patients, which indicated by correlation coefficient 2 with a mean of 0.65 and a maximum of 0.75; and (iii) the total population inflow is a greater predictor of epidemic spread than the population inflow from Wuhan.

scholarly journals Modelling the impact of delaying vaccination against SARS-CoV-2 assuming unlimited vaccine supply

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Marcos Amaku ◽  
Dimas Tadeu Covas ◽  
Francisco Antonio Bezerra Coutinho ◽  
Raymundo Soares Azevedo ◽  
Eduardo Massad
Keyword(s):  
Mathematical Model ◽  
Vaccination Campaign ◽  
Vaccination Rate ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Health Authorities ◽  
The World ◽  
The Moment ◽  
The Impact

Abstract Background At the moment we have more than 177 million cases and 3.8 million deaths (as of June 2021) around the world and vaccination represents the only hope to control the pandemic. Imperfections in planning vaccine acquisition and difficulties in implementing distribution among the population, however, have hampered the control of the virus so far. Methods We propose a new mathematical model to estimate the impact of vaccination delay against the 2019 coronavirus disease (COVID-19) on the number of cases and deaths due to the disease in Brazil. We apply the model to Brazil as a whole and to the State of Sao Paulo, the most affected by COVID-19 in Brazil. We simulated the model for the populations of the State of Sao Paulo and Brazil as a whole, varying the scenarios related to vaccine efficacy and compliance from the populations. Results The model projects that, in the absence of vaccination, almost 170 thousand deaths and more than 350 thousand deaths will occur by the end of 2021 for Sao Paulo and Brazil, respectively. If in contrast, Sao Paulo and Brazil had enough vaccine supply and so started a vaccination campaign in January with the maximum vaccination rate, compliance and efficacy, they could have averted more than 112 thousand deaths and 127 thousand deaths, respectively. In addition, for each month of delay the number of deaths increases monotonically in a logarithmic fashion, for both the State of Sao Paulo and Brazil as a whole. Conclusions Our model shows that the current delay in the vaccination schedules that is observed in many countries has serious consequences in terms of mortality by the disease and should serve as an alert to health authorities to speed the process up such that the highest number of people to be immunized is reached in the shortest period of time.

scholarly journals THE INNOVATIVE POTENTIAL OF HUMAN RESOURCES AS A FACTOR IN THE DEVELOPMENT OF THE INNOVATIVE TECHNOLOGIES MARKET IN UKRAINE

2021 ◽  
Vol 23 (1(78)) ◽  
pp. 58-74
Author(s):  
I.V. GRYSHCHENKO ◽  
V.F. GRYSHCHENKO
Keyword(s):  
Mathematical Model ◽  
Human Resources ◽  
Market Development ◽  
Short Term ◽  
Model Calculations ◽  
Innovative Technologies ◽  
Innovation Capacity ◽  
Innovative Potential ◽  
The Impact ◽  
The Relationship

Topicality. The successful operation of an economic entity, in the development of the innovative technologies market, is largely determined by the innovative potential of its human resources - by the people who work for it - their knowledge, talents, and skills. The wrong combination of these elements, lack of employees who have the necessary qualifications, lack of harmony in the relationship between employers and employees can inevitably lead to serious financial and economic problems. Improving the efficiency of the use of the innovative potential of human resources in the development of the innovative technologies market is one of the most urgent tasks for any business entity. The competitive advantages of business entities, financial and economic indicators of their activity, ensuring sustainable development of entrepreneurship in general, are depending on the degree and balance of its use. Aim and tasks. The purpose of the work is to analyze and develop on its basis recommendations for increasing the level of the innovative potential of human resources in the context of the development of the innovative technologies market in Ukraine. Research results. The article analyzes the main structural elements of the innovative potential of human resources and identifies the factors influencing its level in Ukraine. The results of the analysis allowed us to build an economic and mathematical model of the relationship between innovation capacity, as an indicator of the development of the innovative technologies market and components of the innovative potential of human resources in Ukraine. This made it possible to predict the level of innovation capacity as an indicator of the innovative technologies market development in Ukraine in the short term. The obtained results allowed us to identify problems and develop recommendations for increasing the level of the innovative potential of human resources in the context of the innovative technologies market development in Ukraine. Conclusion. Based on the developed economic and mathematical model, calculations were made that characterize the relationship between innovation capacity as an indicator of the innovative technologies market development and components of the innovative potential of human resources in Ukraine. As shown in the calculations, the proposed economic and mathematical model with high accuracy allows to assess the impact of components of the innovative potential of human resources on innovation capacity and identify major obstacles for its development, which made it possible to predict trends in innovation capacity as an indicator of the innovative technologies market development in Ukraine in the short term.

The impact of ticks on Bufo marinus from native habitats

Parasitology ◽  
1996 ◽  
Vol 113 (2) ◽  
pp. 199-206 ◽  
Author(s):  
M. Lampo ◽  
P. Bayliss
Keyword(s):  
Negative Relationship ◽  
Specific Weight ◽  
Bufo Marinus ◽  
Rate Of Change ◽  
Density Dependent ◽  
Significant Negative Relationship ◽  
Induced Changes ◽  
The Impact ◽  
The Relationship ◽  
Native Habitats

SUMMARYWe analysed the patterns of tick distribution on 2274 adult toads from Venezuela and Brazil, to explore whether these ectoparasites have any impact on the survival of Bufo marinus. A maximum-likelihood analysis showed that aggregation levels of ticks decreased significantly with the mean intensity of infection. This decline could be attributed to a density-dependent reduction of ticks within toads, density-dependent tick-induced toad mortality and/or density-dependent tick-induced changes in toad susceptibility. However, the relationship between the rate of change in tick loads and tick burdens from recaptured toads indicated that neither the loss of ticks within toads nor the toad susceptibility to further infection were dependent upon tick burdens. Therefore, we can indirectly infer that density-dependent tick-induced toad mortality is responsible for the observed decline in aggregation levels with tick age and burdens. On the other hand, a significant negative relationship between tick burdens and the size-specific weight of toads suggested that ticks may also have a significant impact on the patterns of weight deposition of adult toads. This evidence suggests that these ectoparasites may play an important role in regulating the densities of B. marinus in native habitats.

scholarly journals The Impact of Hindlimb Suspension on the Rat Eye: A Molecular and Histological Analysis of the Retina

2021 ◽  
Vol 9 (1) ◽  
pp. 86-103
Author(s):  
Corey A. Theriot ◽  
Patricia Chevez-Barrios ◽  
Thomas Loughlin ◽  
Afshin Beheshti ◽  
Nathaniel D. Mercaldo ◽  
...  
Keyword(s):  
Simulated Microgravity ◽  
Histological Analysis ◽  
Rate Of Change ◽  
Molecular Networks ◽  
Hindlimb Suspension ◽  
Fluid Shifts ◽  
Pigmented Epithelium ◽  
The Impact ◽  
The Relationship ◽  
Tp53 Pathway

Abstract The Spaceflight Associated Neuro-ocular Syndrome (SANS) is hypothesized to be associated with microgravity-induced fluid shifts. There is a need for an animal model of SANS to investigate its pathophysiology. We used the rat hindlimb suspension (HS) model to examine the relationship between the assumed cephalad fluid shifts, intraocular (IOP) pressure and the molecular responses in the retina to the prolonged change in body posture. Long evans rats were subjected to HS up to 90 days. Animals completing 90-day suspension were further studied for recovery periods up to 90 additional days in normal posture. With respect to baseline, the average IOP increase in HS animals and the rate of change varied by cohort. Transcriptomics evidence supported a response to HS in the rat retina that was affected by age and sex. Several molecular networks suggested stress imposed by HS affected the retinal vasculature, oxidative and inflammation status, pigmented epithelium and glia. The CSNK1A1-TP53 pathway was implicated in the response in all cohorts. Sex-specific genes were involved in cytoprotection and may explain sex-dependent vulnerabilities to certain eye diseases. These results support the hypothesis that changes in the biology of the retina subjected to simulated microgravity involve both the neural and vascular retina.

scholarly journals Research on Closed Residential Area Based on Balanced Distribution Theory

2018 ◽  
Vol 38 ◽  
pp. 03001
Author(s):  
Si Lan ◽  
Ni Fang ◽  
Hai Peng Lin ◽  
Shi Qi Ye
Keyword(s):  
Traffic Flow ◽  
Residential Area ◽  
Distribution Model ◽  
The Road ◽  
Resistance Model ◽  
Balanced Distribution ◽  
Residential Quarters ◽  
Opening And Closing ◽  
The Impact ◽  
The Relationship

With the promotion of the street system, residential quarters and units of the compound gradually open. In this paper, the relationship between traffic flow and traffic flow is established for external roads, and the road resistance model is established by internal roads. We propose a balanced distribution model from the two aspects of road opening conditions and traffic flow inside and outside the district, and quantitatively analyze the impact of the opening and closing on the surrounding roads. Finally, it puts forward feasible suggestions to improve the traffic situation and optimize the network structure.

scholarly journals Mathematical Model for Describing Corn Grain Dehydration Kinetics after a Nixtamalization Process

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1771
Author(s):  
Miguel Ángel Gruintal-Santos ◽  
María Teresa Zagaceta-Álvarez ◽  
Karen Alicia Aguilar Cruz ◽  
Juan Reséndiz-Muñoz ◽  
Héctor Eduardo Martinez-Flores ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Rate Of Change ◽  
Proportionality Constant ◽  
Dehydration Rate ◽  
Moisture Percentage ◽  
Cooking Water ◽  
The Mathematical Model ◽  
The Relationship ◽  
Corn Grain ◽  
Corn Grains

In this research, the mathematical model associated with the hydrothermal dehydration process of Nixtamalized Corn Grains (NCG) with different Steeping Time (ST) values, allows the fitting of experimental data with initial moisture M0 and the equilibrium moisture ME as a function of Isothermal Dehydration Time (IDT). The moisture percentage for any time t and dehydration rate (isolines M(t) and isolines vI respectively) of the NCG is shown by means of matrix graphics as a simultaneous function of IDT and ST. The relationship between initial dehydration rate v0 and initial moisture M0 establishes as a function of ST. Also, the mathematical model associated with the solution of the second Fick’s law allows calculating the diffusivity rate vk (H2O molecules out of NCG) and verify that the rate of change in moisture and the dynamical proportionality constant k has a non-linear dependence on the IDT and that k is directly proportional to Deff. The k values strongly relate to ST and the calcium ions percentage into NCG according to solubility lime values into cooking water (or nejayote) as a function of decreasing temperature when ST increases.

scholarly journals The impact of changes in the volume of freight and passenger transportation by water on the GDP of Ukraine

2021 ◽  
Vol 255 ◽  
pp. 01036
Author(s):  
Vadym Gryshchenko ◽  
Iryna Gryshchenko
Keyword(s):  
Mathematical Model ◽  
Water Transport ◽  
Sustainable Development Goals ◽  
Volume Index ◽  
Passenger Transportation ◽  
Target Indicator ◽  
Development Goals ◽  
The Impact ◽  
The Relationship ◽  
Inland Water Transport

The purpose of the article is to analyse the relationship between the GDP volume index and the volume of freight and the number of passengers transported by water in Ukraine in the system of sustainable development goals. The article examines the dynamics of changes in GDP and the situation in the field of maritime and inland water transport in Ukraine. This provided an opportunity to develop an economic and mathematical model of the relationship between the GDP volume index, the volume of freight, and the number of passengers transported by water in Ukraine. Based on the developed economic and mathematical model, the authors predict possible changes in the GDP volume index under the influence of changes in the volume of freight and passenger transported by water transport in Ukraine. The authors propose to increase the values of indicators 9.1.2 and 9.1.3 in the framework of task 9.1 (SDG 9) precisely by increasing the volume of transportation of goods and passengers by water transport. According to the authors, this is most consistent with the conditions of target indicator 8.1.1 (SDG 8) increasing.

scholarly journals Mathematical Model for Charpy Impact Energy of V-Notch Specimens

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Wei Wang ◽  
Ping Wang ◽  
Xuesong Liu ◽  
Zhibo Dong ◽  
Hongyuan Fang
Keyword(s):  
Mathematical Model ◽  
Impact Energy ◽  
Material Properties ◽  
Theoretical Basis ◽  
Impact Resistance ◽  
Charpy Impact ◽  
The Impact ◽  
The Mathematical Model ◽  
The Relationship ◽  
Derivation Process

Firstly, by analyzing the response of Charpy V-notch specimen impacted by pendulum, the relationship between specimen geometry, material properties, and impact energy is established and simplified, and the mathematical model for evaluating impact energy of specimens with different sizes is established. Then, the effectiveness of the model through a series of impact tests is verified. Theoretical analysis and experimental results show that the relationship between ligament length and impact energy is quadratic, while the relationship between ligament thickness and impact energy is linear. In the derivation process, the intrinsic impact toughness is used to evaluate the toughness of materials. The mathematical model makes it possible to evaluate the impact energy of specimens with different sizes and provides a theoretical basis for evaluating the impact resistance of structures.

scholarly journals Modelling the Impact of Delaying Vaccination Against SARS-CoV-2 Assuming Unlimited Vaccines Supply

2021 ◽  
Author(s):  
Eduardo Massad ◽  
Marcos Amaku ◽  
Dimas Tadeu Covas ◽  
Francisco Antonio Bezerra Coutinho ◽  
Raymundo Soares Azevedo
Keyword(s):  
Mathematical Model ◽  
Vaccination Campaign ◽  
Vaccination Rate ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Health Authorities ◽  
The World ◽  
The Moment ◽  
The Impact

Abstract BackgroundAt the moment we have more than 109 million cases and 2.4 million deaths around the world and vaccination represents the only hope to control the pandemic. Imperfections in planning vaccine acquisition and difficulties in implementing distribution among the population, however, have hampered the control of the virus so far.MethodsWe propose a new mathematical model to estimate the impact of vaccination delay against the 2019 coronavirus induces disease (COVID-19) on the number of cases and deaths by the disease in Brazil. We apply the model to Brazil as a whole and to the State of Sao Paulo, the most affected by COVID-19 in Brazil. We simulated the model for the populations of the State of Sao Paulo and Brazil as a whole, varying the scenarios related to vaccine efficacy and compliance from the populations.ResultsThe model projects that, in the absence of vaccination, almost 170 thousand deaths and more than 350 thousand deaths until the end of 2021 for Sao Paulo and Brazil, respectively. If in contrast, Sao Paulo and Brazil had enough vaccine supply and so started a vaccination campaign in January with the maximum vaccination rate, compliance and efficacy, they could have averted more than 112 thousand deaths and 127 thousand deaths, respectively. In addition, that for each month of delay the number of deaths increases monotonically in a logarithm fashion, for both the State of Sao Paulo and Brazil as a whole.ConclusionsOur model shows that the current delay in the vaccination schedules that is observed in many countries has serious consequences in terms of mortality by the disease and should serve as an alert to health authorities to speed the process up such that the highest number of people to be immunized is reached in the shortest period of time.

Sign in / Sign up

Export Citation Format

Share Document