scholarly journals Disease Control in Age Structure Population

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Etienne Kouokam ◽  
Jean-Daniel Zucker ◽  
Franklin Fondjo ◽  
Marc Choisy
Keyword(s):  
Global Sensitivity Analysis ◽  
Reproductive Rate ◽  
Reproduction Rate ◽  
Structure Population ◽  
Leslie Model ◽  
Basic Reproduction Rate ◽  
Closed Systems ◽  
Public Health Strategies ◽  
Influential Parameters ◽  
Disease Free

We combine the Leslie model and its derivatives with the classical compartmental SIRS models to build a model of transmission of infected diseases, in a population of hosts, whether opened or closed systems. We calculate the basic reproductive rate R0. Under certain conditions, when R0<1, there is a disease-free equilibrium that is locally asymptotically stable. In contrast, when R0>1, this equilibrium is unstable. Then, through an example, we show how we can define public health strategies to tackle an endemic. Finally we carry a global sensitivity analysis based on this basic reproduction rate to exhibit the most influential parameters of our model that are applied to influenza.

scholarly journals Mathematical model for acquiring immunity to malaria: a PDE approach

BIOMATH ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 2107227
Author(s):  
S Y Tchoumi ◽  
Y T Kouakep ◽  
D J M Fotsa ◽  
F G T Kamba ◽  
J C Kamgang ◽  
...  
Keyword(s):  
Differential Equation ◽  
Mathematical Model ◽  
Partial Differential Equation ◽  
Differential Equations ◽  
Numerical Simulations ◽  
Spectral Radius ◽  
Human Population ◽  
Reproduction Rate ◽  
Basic Reproduction Rate ◽  
Disease Free

We develop a new model of integro-differential equations coupled with a partial differential equation that focuses on the study of the? naturally acquiring immunity to malaria induced by exposure to infection. We analyze a continuous acquisition of immunity after infected individuals are treated. It exhibits complex and realistic mechanisms precised mathematically in both disease free or endemic context and in several numerical simulations showing the interplay between infection through the bite of mosquitoes. The model confirms the (partial) premunition of the human population in the regions where malaria is endemic. As common in literature, we indicate an equivalence of the basic reproduction rate as the spectral radius of a next generation operator.

scholarly journals Global Sensitivity Analysis of a Homogenized Constrained Mixture Model of Arterial Growth and Remodeling

2021 ◽  
Author(s):  
Sebastian Brandstaeter ◽  
Sebastian L. Fuchs ◽  
Jonas Biehler ◽  
Roland C. Aydin ◽  
Wolfgang A. Wall ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Global Sensitivity Analysis ◽  
Model Parameters ◽  
Computational Studies ◽  
Growth And Remodeling ◽  
Global Sensitivity ◽  
Output Variability ◽  
Constrained Mixture ◽  
The One ◽  
Influential Parameters

AbstractGrowth and remodeling in arterial tissue have attracted considerable attention over the last decade. Mathematical models have been proposed, and computational studies with these have helped to understand the role of the different model parameters. So far it remains, however, poorly understood how much of the model output variability can be attributed to the individual input parameters and their interactions. To clarify this, we propose herein a global sensitivity analysis, based on Sobol indices, for a homogenized constrained mixture model of aortic growth and remodeling. In two representative examples, we found that 54–80% of the long term output variability resulted from only three model parameters. In our study, the two most influential parameters were the one characterizing the ability of the tissue to increase collagen production under increased stress and the one characterizing the collagen half-life time. The third most influential parameter was the one characterizing the strain-stiffening of collagen under large deformation. Our results suggest that in future computational studies it may - at least in scenarios similar to the ones studied herein - suffice to use population average values for the other parameters. Moreover, our results suggest that developing methods to measure the said three most influential parameters may be an important step towards reliable patient-specific predictions of the enlargement of abdominal aortic aneurysms in clinical practice.

scholarly journals Influential parameters for estimating the environmental impacts of geothermal power: A global sensitivity analysis study

2021 ◽  
Vol 3 ◽  
pp. 100054
Author(s):  
Andrea Paulillo ◽  
Aleksandra Kim ◽  
Christopher Mutel ◽  
Alberto Striolo ◽  
Christian Bauer ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Environmental Impacts ◽  
Global Sensitivity Analysis ◽  
Analysis Study ◽  
Global Sensitivity ◽  
Geothermal Power ◽  
Influential Parameters

scholarly journals INDEPENDENT ASSOCIATION OF METEOROLOGICAL CHARACTERISTICS WITH INITIAL SPREAD OF COVID-19 IN INDIA

2020 ◽  
Author(s):  
Hemant Kulkarni ◽  
Harshwardhan Vinod Khandait ◽  
Uday Wasudeorao Narlawar ◽  
Pragati G Rathod ◽  
Manju Mamtani
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Meteorological Data ◽  
Reproduction Rate ◽  
The Novel ◽  
Total N ◽  
Mobility Data ◽  
Basic Reproduction Rate ◽  
Independent Association ◽  
Novel Coronavirus

Whether weather plays a part in the transmissibility of the novel COronaVIrus Disease-19 (COVID-19) is still not established. We tested the hypothesis that meteorological factors (air temperature, relative humidity, air pressure, wind speed and rainfall) are independently associated with transmissibility of COVID-19 quantified using the basic reproduction rate (R0). We used publicly available datasets on daily COVID-19 case counts (total n = 108,308), three-hourly meteorological data and community mobility data over a three-month period. Estimated R0 varied between 1.15-1.28. Mean daily air temperature (inversely) and wind speed (positively) were significantly associated with time dependent R0, but the contribution of countrywide lockdown to variability in R0 was over three times stronger as compared to that of temperature and wind speed combined. Thus, abating temperatures and easing lockdown may concur with increased transmissibility of COVID-19.

scholarly journals Autophagy contributes to the feeding, reproduction, and mobility of Bursaphelenchus xylophilus at low temperatures

2019 ◽  
Vol 51 (8) ◽  
pp. 864-872 ◽  
Author(s):  
Hongbin Liu ◽  
Xiaoqin Wu ◽  
Yaqi Feng ◽  
Lin Rui
Keyword(s):  
Defense Mechanisms ◽  
Feeding Rate ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Reproductive Rate ◽  
Reproduction Rate ◽  
Marker Proteins ◽  
Physiological Homeostasis ◽  
Autophagic Activity ◽  
Growth And Reproduction

Abstract The pine wood nematode (PWN), Bursaphelenchus xylophilus, is the pathogen causing pine wilt disease (PWD), which is a devastating forest disease. At present, little is known about the defense mechanisms of the PWN, which limits PWD control. Although autophagy plays an important role in the physiological and pathological processes of eukaryotes, its significance in the PWN remains unknown. In this study, we prepared an anti-BxATG8 polyclonal antibody and identified two PWN autophagy marker proteins: BxATG8-I and BxATG8-II. By western blot analysis, we found that the ratio of BxATG8-II to BxATG8-I, which represents autophagic activity, was decreased significantly when samples were treated with the autophagy inhibitor 3-methyladenine. As such, we were able to successfully detect and quantify autophagic activity in the PWN. Thereafter, we investigated the effects of low and high temperatures on PWN growth and reproduction. The results revealed that feeding rate, reproduction rate, and mobility decreased at 15°C and increased at 35°C. By contrast, autophagic activity was high at 15°C and low at 35°C, suggesting that the PWN regulates autophagic activity in response to changes in temperature to maintain physiological homeostasis. When autophagy was inhibited at 15°C, feeding rate, reproductive rate, and mobility declined further, indicating that autophagy is crucial for PWN growth and reproduction at low temperature. These results indicate that autophagy in the PWN is an important response mechanism to temperature changes.

scholarly journals Estimating the basic reproduction rate of HFMD using the time series SIR model in Guangdong, China

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0179623 ◽  
Author(s):  
Zhicheng Du ◽  
Wangjian Zhang ◽  
Dingmei Zhang ◽  
Shicheng Yu ◽  
Yuantao Hao
Keyword(s):  
Time Series ◽  
Sir Model ◽  
Reproduction Rate ◽  
Basic Reproduction Rate

scholarly journals An SIRS epidemic model of Japanese Encephalitis

1994 ◽  
Vol 17 (2) ◽  
pp. 347-355 ◽  
Author(s):  
B. B. Mukhopadhyay ◽  
P. K. Tapaswi
Keyword(s):  
Japanese Encephalitis ◽  
Epidemic Model ◽  
Human Population ◽  
Control Measure ◽  
Passive Immunization ◽  
Coupled System ◽  
Reproductive Rate ◽  
Free System ◽  
Sirs Epidemic Model ◽  
Disease Free

An epidemiological model of the dynamics of Japanese Encephalitis (J.E.) spread coupling the SIRS (Susceptible/Infected/Removal/Susceptible) models of J.E. spread in the reservoir population and in the human population has been proposed. The basic reproductive rateR(0)in the coupled system has been worked out. Using Aron's results (cf. [1] and [2]), it has been observed that the disease-free system is stable in this coupled system also, ifR(0)is less than unity, and ifR(0)is greater than unity, the disease-free system is unstable and there exists a unique stable endemic equilibrium.The model also shows that in contrast to Aron's observations, loss of immunity is independent of the rate of exposure to the disease. This observation sheds light on the control measure of J.E. by vaccination. Passive immunization, i.e., administration of antibody at recurrent intervals is the correct method of vaccination to eradicate the disease.

A COMPARTMENTAL MODEL OF SLEEPING SICKNESS IN CENTRAL AFRICA

1996 ◽  
Vol 04 (04) ◽  
pp. 459-477 ◽  
Author(s):  
MARC ARTZROUNI ◽  
JEAN-PAUL GOUTEUX
Keyword(s):  
Compartmental Model ◽  
Equilibrium Points ◽  
Central Africa ◽  
Sleeping Sickness ◽  
Tsetse Flies ◽  
Reproduction Rate ◽  
Basic Reproduction Rate ◽  
The Stability ◽  
The Impact ◽  
Percent Decrease

We present a five-variable compartmental model for the spread of Trypanosoma brucei gambiense, the parasite responsible for the transmission (through tsetse flies) of sleeping sickness in Central Africa. The model’s equilibrium points depend on two “summary parameters”: gr, the proportion removed among human infectives, and R0, the basic reproduction rate. Stability results are obtained for the origin but not for other equilibrium points. A two-variable simplified version of the model is presented and the stability of all its equilibrium points can be investigated analytically. Both models are applied to the Niari focus of Central Africa and used to test the impact of a vector control strategy. The models’ results are in agreement with the extinction of the epidemic that was brought about by a fifty percent decrease in vector density.

scholarly journals Resistance and tolerance of ten carrot cultivars to the hawthorn-carrot aphid, Dysaphis crataegi Kalt., in Poland

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247978
Author(s):  
Maria Pobożniak ◽  
Małgorzata Gaborska ◽  
Tomasz Wójtowicz
Keyword(s):  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Reproductive Period ◽  
Field Resistance ◽  
Intrinsic Rate Of Increase ◽  
Demographic Parameters ◽  
Reproduction Rate ◽  
Net Reproductive Rate ◽  
Rate Of Increase

Damage caused to cultivated carrots by the hawthorn-carrot aphid, Dysaphis crataegi Kalt. (Hemiptera: Aphididae) is one of the factors limiting carrot production in Poland. Planting resistant and tolerant cultivars could reduce yield losses due to the damage caused by this pest. This study was conducted to evaluate the resistance and/or tolerance of 10 carrot genotypes to hawthorn-carrot aphid. Their field resistance was determined under field conditions based on five indicators, namely, mean number of alates (migrants) per plant and mean percentage of plants colonized by them, mean seasonal number of aphids per plant, mean number of aphids per plant and mean percentage of infested plants at peak abundance. Antibiosis experiments were conducted under laboratory conditions and pre-reproductive, reproductive time, fertility, and demographic parameters, represented by the net reproduction rate (Ro), intrinsic rate of increase (rm) and mean generation time (T), were calculated. Five cultivars, Afro F1, Nipomo F1, Samba F1, White Satin F1, and Yellowstone showed field resistance. Antibiosis experiments revealed significant differences among the carrot cultivars in the length of the reproductive period, female fecundity in the time equal to the pre-reproduction time, and total progeny of hawthorn-carrot aphid. The intrinsic rate of natural increase (rm) for apterous aphids varied significantly, ranging between 0.181 (Nipomo F1) and 0.343 females/female/day (White Satin F1). Additionally, the estimated net reproductive rate (R0) was the lowest on Nipomo F1, and this genotype was determined to be resistant. Our results suggest that a very high density of trichomes on the leaf petioles (71.94 trichomes/cm2) could adversely affect the feeding, bionomy, and demographic parameters of hawthorn-carrot aphid on the cultivar Nipomo F1. In addition, Napa F1 and Kongo F1 demonstrated high tolerance. Considering all the results collectively, four genotypes, Afro F1, Kongo F1, Napa F1 and Nipomo F1, were relatively resistant/tolerant to the hawthorn-carrot aphid.

scholarly journals COVID-19 Epidemic Dynamics and Population Projections from Early Days of Case Reporting in a 40 million population from Southern India

2020 ◽  
Author(s):  
Rashmi Pant ◽  
Lincoln P. Choudhury ◽  
Jammy G. Rajesh ◽  
Vijay V. Yeldandi
Keyword(s):  
Population Projections ◽  
Reproduction Rate ◽  
Social Distancing ◽  
Epidemic Dynamics ◽  
Transmission Parameters ◽  
Basic Reproduction Rate ◽  
South Indian ◽  
Indian State ◽  
The Government ◽  
Government Records

AbstractIndia reported its first COVID19 case on 30 January 2020. Since then the epidemic has taken different trajectories across different geographical locations in the country. This study explores the population aggregated trajectories of COVID19 susceptible, infected and recovered or dead cases in the south Indian state of Telangana with a population of approximately 40 million. Information on cases reported from March 2 to April 4 was collated from government records. The susceptible-infected-removed (SIR) model for the spread of an infectious disease was used. Transmission parameters were extracted from existing literature that has emerged over past weeks from other regions with similar population densities as Telangana. Optimisation algorithms were used to get basic reproduction rate for different phases of nonpharmaceutical interventions rolled by the government. Peak accumulation is projected towards end of July with 36% of the population being infected by August 2020 if the population lockdown or social distancing mechanism is not continued. The number of deaths assuming no intervention is projected to be 488000 (95% CI: (329400, 646600)). A draconian enforcement of population lockdown combined with hand and face hygiene adherence would reduce the transmission by at least 99.7% whereas partial social distancing and hygiene would reduce it by 51.2%. Transmission parameters reported should be interpreted with caution as they are population aggregated and do not consider unique characteristics of susceptibility among micro-clusters and vulnerable individuals. More data will need to be collected to optimize transmission parameters and evaluate the full complexity, to simulate real world scenarios in the models.

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