Analysis and optimization based on a sex pheromone and pesticide pest model with gestation delay

2019 ◽  
Vol 12 (05) ◽  
pp. 1950054
Author(s):  
Shu Xiang ◽  
Yongzhen Pei ◽  
Xiyin Liang
Keyword(s):  
Sex Pheromone ◽  
Mating Disruption ◽  
Optimal Parameter ◽  
Extinction Risk ◽  
Attractive Alternative ◽  
Gestation Delay ◽  
The Stability ◽  
Species Specific ◽  
The Cost ◽  
The Impact

Sex pheromone, aiming at mating disruption (MD), being species specific and leaving no toxic residues in the produce grown, offers an attractive alternative to conventional pesticides. In this paper, by incorporating the gestation delay and sex pheromone, we explore the impact of MD control on the dynamic behaviors of pest system. Firstly, the boundness, stability and bifurcation of system are deliberated. Secondly, an optimal control problem based on sex pheromone and pesticide is transformed into an equivalent optimal parameter selection problem by introducing the constrain violation function. Additionally, the gradients of the cost function with respect to the dose of sex pheromone and the killing rate are given. Furthermore, simulations are executed to validate the validity of our method. Meanwhile, our results indicate that gestation delay increases the extinction risk of the population and liberating sex pheromone destroys the stability of equilibrium states.

Liberalization at Any Cost? Implications of IMF Policy for Sovereignty and Stability in East Asia

2000 ◽  
Vol 15 (1) ◽  
pp. 43-56
Author(s):  
Michael Spaulding
Keyword(s):  
East Asia ◽  
International Political Economy ◽  
Free Market ◽  
East Asian ◽  
Financial Governance ◽  
State Governance ◽  
The Stability ◽  
Cost Implications ◽  
The Cost ◽  
The Impact

Globalization pits pressures for liberalization against state claims to political and economic sovereignty. Less powerful states in particular face strong pressure from the international trade regime to liberalize their economies irrespective of the impact on domestic stability and national goals. East Asia has been a hold-out against the global trend toward liberalization. This paper shows that the bail-out package demanded by the IMF in 1997 during the East Asian financial crisis imposed unprecedented restrictions on state governance without regard for long-term implications. The paper argues that the IMF's motivation was to harmonize financial governance of the affected economies with Western practices. However, the cost of this initiative to the stability of the region has been overlooked. The East Asian region has carved out for itself a unique niche in the international political economy by resisting penetration of Western finance capital. Already governments have fallen and deep resentments have been sewn over the reversal. More seriously for the future, assumptions that free-market liberalism can be imposed top-down ignore the extent to which economic institutions and preferences are embedded in culture.

Fear Induced Stabilization in an Intraguild Predation Model

2020 ◽  
Vol 30 (04) ◽  
pp. 2050053
Author(s):  
Mainul Hossain ◽  
Nikhil Pal ◽  
Sudip Samanta ◽  
Joydev Chattopadhyay
Keyword(s):  
Growth Rate ◽  
Hopf Bifurcation ◽  
Intraguild Predation ◽  
Equilibrium Points ◽  
Stable Limit ◽  
Interior Equilibrium ◽  
The Rich ◽  
The Stability ◽  
The Cost ◽  
The Impact

In the present paper, we investigate the impact of fear in an intraguild predation model. We consider that the growth rate of intraguild prey (IG prey) is reduced due to the cost of fear of intraguild predator (IG predator), and the growth rate of basal prey is suppressed due to the cost of fear of both the IG prey and the IG predator. The basic mathematical results such as positively invariant space, boundedness of the solutions, persistence of the system have been investigated. We further analyze the existence and local stability of the biologically feasible equilibrium points, and also study the Hopf-bifurcation analysis of the system with respect to the fear parameter. The direction of Hopf-bifurcation and the stability properties of the periodic solutions have also been investigated. We observe that in the absence of fear, omnivory produces chaos in a three-species food chain system. However, fear can stabilize the chaos thus obtained. We also observe that the system shows bistability behavior between IG prey free equilibrium and IG predator free equilibrium, and bistability between IG prey free equilibrium and interior equilibrium. Furthermore, we observe that for a suitable set of parameter values, the system may exhibit multiple stable limit cycles. We perform extensive numerical simulations to explore the rich dynamics of a simple intraguild predation model with fear effect.

scholarly journals A natural experiment reveals the impact of hydroelectric dams on the estuaries of tropical rivers

2019 ◽  
Vol 5 (3) ◽  
pp. eaau9875 ◽  
Author(s):  
E. Ezcurra ◽  
E. Barrios ◽  
P. Ezcurra ◽  
A. Ezcurra ◽  
S. Vanderplank ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Economic Consequences ◽  
Coastal Sediments ◽  
Coastal Protection ◽  
Hydroelectric Dams ◽  
Sediment Trapping ◽  
Tropical Estuaries ◽  
The Stability ◽  
The Cost ◽  
The Impact

We tested how sediment trapping by hydroelectric dams affects tropical estuaries by comparing two dammed and two undammed rivers on Mexico’s Pacific coast. We found that dams demonstrably affected the stability and productivity of the estuaries. The two rivers dammed for hydroelectricity had a rapid coastal recession (between 7.9 and 21.5 ha year−1) in what should otherwise be an accretional coastline. The economic consequences of this dam-induced coastal erosion include loss of habitat for fisheries, loss of coastal protection, release of carbon sequestered in coastal sediments, loss of biodiversity, and the decline of estuarine livelihoods. We estimate that the cost of the environmental damages a dam can cause in the lower part of basin almost doubles the purported benefits of emission reductions from hydroelectric generation.

scholarly journals A modeled radiological dispersive device release and the impact to decision-making in an urban environment

2020 ◽  
Vol 35 (4) ◽  
pp. 316-322
Author(s):  
Paulo Oliveira ◽  
Ubiratan Oliveira ◽  
Ricardo Stenders ◽  
Ademir Silva ◽  
Helio Vital ◽  
...  
Keyword(s):  
Decision Making ◽  
Early Stage ◽  
Radioactive Material ◽  
Sensitive Information ◽  
Training Environment ◽  
Stability Class ◽  
Radiological Dispersion Device ◽  
The Stability ◽  
The Cost ◽  
The Impact

A radiological dispersion device is a weapon that combines radioactive material with conventional explosives for spreading radioactive material across an inhabited area. This study is focused on evaluating key parameters in an radiological dispersion device scenario. The calculations were performed to include two different situations: by using explosives and by simple mechanical release. Simulations were conducted with the use of the HotSpot Health Physics Codes. The results suggest the existence of significant correlations between stability classes in scenarios where they evolve with time, producing alternations between them. As long as the stability class remains constant, this latter finding offers the possibility of creating a suitable response, based on temporal evolutions. Therefore, the purpose of this study is to: estimate the size of the potentially affected population, estimate absorbed doses, and estimate the cost-effectiveness in order to help initial responses by providing time-sensitive information about the event. A methodology capable of providing useful information allows prompt decisions and initial assessments of future risks to be made efficiently. This approach can also provide a training environment for the personnel responsible for the decision-making at an early stage of the response.

Analysis of Earth Berm on the Impact of Cantilever Retaining Structure Based on ABAQUS

2014 ◽  
Vol 1065-1069 ◽  
pp. 3-6 ◽  
Author(s):  
Zhen Yu Wu ◽  
Zhong Yuan Duan
Keyword(s):  
Bending Moment ◽  
Horizontal Displacement ◽  
Retaining Structure ◽  
Supporting Structure ◽  
The Stability ◽  
The Cost ◽  
The Impact

Software ABAQUS was carried out to analyze the effect of earth berms on behavior of cantilever retaining structure, and the soil was in modified Cambridge model. The results showed that: in the premise of ensuring the stability of earth berm itself, height and width of earth berm increased reasonably can reduce the horizontal displacement and bending moment of supporting structure, so as to improve the safety of the supporting structure, and save the cost of project.

scholarly journals A reappraisal of the vital effect in benthic foraminifera on Mg/Ca ratios: species specific uncertainty relationships

2012 ◽  
Vol 9 (4) ◽  
pp. 4947-4977
Author(s):  
J. C. Wit ◽  
L. J. de Nooijer ◽  
C. Barras ◽  
F. Jorissen ◽  
G. J. Reichart
Keyword(s):  
Individual Variability ◽  
Measured Temperature ◽  
Temperature Calibration ◽  
Ecological Strategy ◽  
Vital Effect ◽  
The Stability ◽  
Species Specific ◽  
The Impact ◽  
Number Of Individuals ◽  
Foraminiferal Test

Abstract. The reconstruction of past temperatures is often achieved through measuring the Mg/Ca value of foraminiferal test carbonate. The diversity in foraminiferal Mg/Ca-temperature calibrations suggests that there is also a biological control on this proxy. This study presents a new Mg/Ca-temperature calibration for the benthic foraminifer Bulimina marginata, based on cultures under a range of temperatures (4–14 ° C). Measured Mg/Ca values for B. marginata correlate well with temperature (Mg/Ca = 1.10 ± 0.10e0.045 ± 0.009T, R2=0.28, p<0.01). The inter-individual variability is, however, also significant (standard deviation is 10–35 % of the average). Before applying this or any calibration, the effect of the inter-individual variability on the accuracy of the Mg/Ca-temperature calibration has to be evaluated. The inter-individual variability is quantified and split in three components, namely (1) an analytical error; (2) an environmental effect and (3) a vital effect. The effect of inter-individual variability on the accuracy of Mg/Ca-temperature calibrations is depending on the sensitivity of the used calibration and the number of individuals measured (Temperature uncertainty = (0.33 · N−0.50)/sensitivity). The less sensitive a calibration, the greater is the impact of inter-individual variability. This can partly be circumvented by measuring more individuals. Differences in sensitivity may depend on the stability of the environment in which the foraminifera live and the concurring ecological strategy. This study shows the link between inter-individual variability en sensitivity and their influence on the accuracy of \\Mg/Ca-temperature calibrations.

scholarly journals Economic Security of the Region: Evaluation and Security Mechanisms

2019 ◽  
pp. 83-93
Author(s):  
Marina Buyanova ◽  
Irina Averina ◽  
Alina Kulakova
Keyword(s):  
Economic System ◽  
Economic Security ◽  
Public Authorities ◽  
Volgograd Region ◽  
The Russian Federation ◽  
The Stability ◽  
Definition Of ◽  
The Cost ◽  
The Impact ◽  
Integral Indicator

Modern globalization processes cause the emergence of new threats to society, and necessitate the development of innovative mechanisms to overcome them in order to improve the level of security at various levels of management. The objective of this study is to test the methodology for assessing the level of security of the economic system of the region (based on the use of an integral indicator), as well as the definition of mechanisms for its provision at the meso-level. The structure of this indicator includes aspects of the impact on the stability of the system of the following factors (market, non-market and social ones), based on the system of indicators (the number of employed population, the cost of technological innovation per capita, investment in fixed capital, etc.). The calculation of summary indicators is given on the example of one of the subjects of the Russian Federation (Volgograd region), which allowed to determine negative changes in the level of economic security in the region (significant technological backwardness, consistent depletion of natural resources, growth of budget commitments, etc.). Due to the comprehensive assessment, a list of factors that cause this condition has been identified with the aim of further targeted impact from public authorities to overcome the negative trends in the economic system of the region and (or) leveling their consequences. The development of mechanisms to ensure the economic security of the region, based on the above-mentioned method of integrated assessment, allows not only to fully assess the state of the regional economy, but also to identify the potential to strengthen the position of the entity of the country both at the national and international arena.

scholarly journals Analysis of rock mass behavior with Empirical and Numerical method for the construction of diversion tunnel, Laos

2022 ◽  
Vol 1212 (1) ◽  
pp. 012028
Author(s):  
D J W Mboussa ◽  
S Sun
Keyword(s):  
Numerical Modeling ◽  
Rock Mass ◽  
Field Investigation ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Mountain Area ◽  
Diversion Tunnel ◽  
The Stability ◽  
The Cost ◽  
The Impact

Abstract Tunneling construction in the mountain area is a challenge for engineers and geotechnicians because of instability due to the presence of discontinuities. The objective of this paper is the modeling of surrounding rock masses for the stability of the diversion tunnel to predict the behavior of rock masses during the excavation process for the Nam Phoun hydropower station project in Laos. Field investigation and laboratories test was realized; Empirical methods as Rock mass designation and Geological Strength Index were performed, rock masses were classified in three categories (RM-1, RM-2, and RM-3); in situ stresses were obtained from existing equations, numerical modeling was performed by the 2D plane strain finite element code Phase2 developed by Rocscience, using Generalized Hoek-Brown criterion for each type of rock masses. The results of numerical modeling show the strength zones of stresses and deformations around the tunnel and predict the instabilities around the tunnel during excavations processes. Thus, for all rock’s masses, it will be necessary to consider an analysis for the supports design before the excavation’s process. The findings of this study allow a clearer understanding of the importance to assess a predictive analysis of slope stability during the feasibility phase of a project by engineers to have an idea of instabilities and its significant in preventing the impact on the cost of the project.

scholarly journals Research on the Side Deflection of the Saw Band of a Joinery Band Saw Influenced by the Selected Technical and Technological Factors

2020 ◽  
Vol 28 (3) ◽  
pp. 148-153
Author(s):  
Jozef Krilek ◽  
Tomáš Kuvik ◽  
Ján Kováč ◽  
Ján Melicherčík
Keyword(s):  
Tensile Stress ◽  
Work Productivity ◽  
Theoretical Assumption ◽  
Technological Factors ◽  
Cutting Rate ◽  
The Stability ◽  
Band Saw ◽  
The Cost ◽  
The Impact

AbstractThe paper focuses on measuring and evaluating the impact of selected technical and technological factors -the height of adjustable guides and stretching force - on the side deflection of the saw band of a joinery band saw. There is a detailed description of the ways the side deflection can be measured. In order to find out the intensity of the stretching force was used portable tension meter SANDVIK 5000, enabling to check the tensile stress in the saw blades of a gang saw or in the saw bands of a band saw. The actual experiment was conducted on a joinery band saw, at the cutting rate vc = 15 m·s-1. The results of the measurements confirmed the theoretical assumption of the impact of the selected technical and technological factors on the stability of the saw band, where the side deflection decreases with increasing stretching force and increases with increasing height of the guides. The stability of the saw band affects the quality of the surface to be treated, thus saving the cost of machining the workpiece and making work productivity more efficient.

scholarly journals Dynamics of an Epidemic Model under the Influence of Environmental Stress

2021 ◽  
Vol 16 (2) ◽  
pp. 201-243
Author(s):  
Sangeeta Saha ◽  
Guruprasad Samanta
Keyword(s):  
Environmental Stress ◽  
Environmental Pollution ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Equilibrium Points ◽  
Dynamical Behaviour ◽  
Treatment Policy ◽  
The Stability ◽  
The Cost ◽  
The Impact

We have considered a compartmental epidemiological model with infectious disease to observe the influence of environmental stress on disease transmission. The proposed model is well-defined as the population at each compartment remains positive and bounded with time. Dynamical behaviour of the model is observed by the stability and bifurcation analysis at the equilibrium points. Also, numerical simulation supports the theoretical proofs and the result shows that the system undergoes a forward bifurcation around the disease-free equilibrium. Our results indicate that with the increase of environmental pollution, the overall infected population increases. Also, the disease transmission rate among the susceptible and stressed population from asymptomatically infected individuals plays a crucial role to make a system endemic. A corresponding optimal control problem has also been proposed to control the disease prevalence as well as to minimize the cost by choosing the vaccination policy before being infected and treatment policy to the infected as control variables. Numerical figures indicate that the vaccination provided to susceptible needs some time to reduce the disease transmission but the vaccination provided to stressed individuals works immediately after implementation. The treatment policy for symptomatically infected individuals works with a higher rate at an earlier stage but the intensity decreases with time. Simultaneous implementation of all control interventions is more useful to reduce the size of overall infective individuals and also to minimize the economic burden. Hence, this research clearly expresses the impact of environmental pollution (specifically the influence of environmental stress) on the disease transmission in the population.

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