An iterative continuous-event model of the population outbreak of a phytophagous Hemipteran

2021

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The course of an infection was modeled as a controlled nonlinear process. Understanding the substantial differences observed in the trajectory of the disease caused by the new coronavirus SARS-CoV-2 is of critical importance at the moment. Numerous factors have been considered to explain the fact that symptoms vary highly among different people and the infection transmission rate varies among local populations. Virus replication within the host cell and the development of an immune response to virus antigens in the body are two interdependent processes, which have aftereffects and depend on the preexisting states of the cell and virus populations. Different scenarios with the same input parameters are necessary to consider for modeling the properties of the states. The efficiency of the immune response is the most important factor, including the time it takes to develop defense responses from three levels of the immune system, which is a complex system of the body. A computational description of infection scenarios was proposed on the basis of a delay differential equation with two values of the time lag. In the new model, transitions between phases of infectious disease depend on the initial virus dose and the delayed immune response to infection. A variation in the dose of the virus and response time can lead to a transition from an acute phase of the disease with overt symptoms to a chronic phase or fatal outcome. Asymptomatic transmission of viral infection was calculated and described in the model as a situation where the virus is rapidly and efficiently suppressed after a short replication phase, while still persisting in the body in minor amounts. An analysis of the model behavior is consistent with the theory that the initial number of virions can affect the quality of the immune response. The reasons that high individual differences are observed in the trajectory of COVID-19 disease and the formation of types of the immune response to coronavirus are still poorly understood. Known trajectories of hepatitis C virus (HCV) infection were used as a basis for model scenarios.

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Section: Different and Common Features Of Epidemic Processes Upon Their Globalizationmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: The Interpretation Of the Aggregate Delaymentioning

confidence: 96%

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A Continuous Model of Three Scenarios of the Infection Process with Delayed Immune Response Factors

2021

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“…The arsenal of descriptive tools for iteration dynamics is wide, although limited [ 70 ]. Three topological forms of attractors are available for iterations, namely, a finite period cycle or an equilibrium point , an attractor similar to a Cantor set, and an interval attractor in the form of a conjugation of an uncountable set of segments.…”

Section: A Methods For Analyzing Discrete Iterations Of a Hybrid Modelmentioning

confidence: 99%

Hybrid Model of the Collapse of the Commercial Crab Paralithodes camtschaticus (Decapoda, Lithodidae) Population of the Kodiak Archipelago

2022

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Degradation of commercial populations remains a frequent phenomenon even with the use of methods of stocktaking and control of production volume. In fish farming, the concept of “overfishing” is used with and the signs of this condition are well known. However, the processes leading to the degradation of reserves develope in various ways. According to the theory of nonlinear dynamical systems, several types of crisis development can be classified. Of particular interest are the phenomena of collapse, that is, variants of a rapid decline in numbers, which are unexpected for the organizations controlling the fishery. Immediately before the collapse, the state of the stock can be assessed as relatively stable and it may experience fluctuations. Contrary to expectations, there was no rapid recovery after a rapid reduction in cod, whitefish Coregonus clupeaformis of the Great Lakes, halibut and other valuable species. This paper considers a hybrid model for the collapse of red king crab Paralithodes camtschaticu s stocks of the Kodiak archipelago of Alaska with unusual distinctive oscillating dynamics. The computational scenario in a hybrid system with survival and growth equations considers the logic of decision-making in operation management. The scenario differs in that after the fall of catches, the crab population goes into the sporadic fluctuations that do not have a regular character and are not characteristic of the population. The collapse itself occurs after a long interval of fishing while the population is in an unstable mode. The analysis shows that a long species life cycle is not a decisive factor for eliminating the risk of a collapse scenario. The presence of reserve generations does not change the situation qualitatively, the efficiency of their reproduction in crab and cod off the coast of Labrador turned out to be unexpectedly low. The status of stocks of large predators that require seasonal moratoriums on fishing must be regularly checked.

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A Continuous Model for Oscillating Outbreaks of the Population of a Phytophagous Moth, the Tent Caterpillar, Malacosoma disstria (Lepidoptera, Lasiocampidae)

2020