scholarly journals Best experienced payoff dynamics and cooperation in the centipede game

2019 ◽  
Vol 14 (4) ◽  
pp. 1347-1385 ◽  
Author(s):  
William H. Sandholm ◽  
Segismundo S. Izquierdo ◽  
Luis R. Izquierdo
Keyword(s):  
Stable State ◽  
Fixed Number ◽  
Cooperative Play ◽  
Game Dynamics ◽  
Testing Strategies ◽  
Study Population ◽  
Population Game ◽  
Globally Stable

We study population game dynamics under which each revising agent tests each of his strategies a fixed number of times, with each play of each strategy being against a newly drawn opponent, and chooses the strategy whose total payoff was highest. In the centipede game, these best experienced payoff dynamics lead to cooperative play. When strategies are tested once, play at the almost globally stable state is concentrated on the last few nodes of the game, with the proportions of agents playing each strategy being largely independent of the length of the game. Testing strategies many times leads to cyclical play.

Comparison Between Different Growth Functions of the Jatropha Curcas Plant with Random Attack Pattern of Whitefly

2021 ◽  
Vol 24 (4) ◽  
pp. 382-390
Author(s):  
Roshmi Das ◽  
Ashis Kumar Sarkar
Keyword(s):  
Growth Rate ◽  
Jatropha Curcas ◽  
Stable State ◽  
Stable Limit Cycle ◽  
Stable Limit ◽  
Deterministic Models ◽  
Growth Functions ◽  
Attack Pattern ◽  
Parameter Values ◽  
Globally Stable

We have proposed here two deterministic models of Jatropha Curcas plant and Whitefly that simulate the dynamics of interaction between them where the distribution of Whitefly on plant follows Poisson distribution.In the first model growth rate of the plant is assumed to be in logistic form whereas in the second model it is taken as exponential form. The attack pattern and the growth of the whitefly are assumed as Holling type II function.The first model results a globally stable state and in the second one we find a globally attracting steady state for some parameter values,and a stable limit cycle for some other parameter values. It is also shown that there exist Hopf bifurcation with respect to some parameter values. The paper also discusses the question about persistence and permanence of the model. It is found that the specific growth rate of both the population and attack pattern of the whitefly governs the dynamics of both the models.

Global stability of genetic systems governed by mutation and selection

1976 ◽  
Vol 80 (2) ◽  
pp. 331-336 ◽  
Author(s):  
P. A. P. Moran
Keyword(s):  
Global Stability ◽  
Stable State ◽  
Single Locus ◽  
Genetic Systems ◽  
Infinite Set ◽  
Globally Stable ◽  
Mutation And Selection

AbstractThis paper considers the behaviour of infinite haploid genetic populations under the influence of mutation and selection depending on a single locus. Under wide conditions the Perron–Frobenius theory of non-negative matrices and its generalization by Vere-Jones are used to prove that there is a single globally stable state of the population when there is a finite or, under more restrictive conditions, an infinite set of possible alleles.

scholarly journals Group testing for SARS-CoV-2 allows for up to 10-fold efficiency increase across realistic scenarios and testing strategies

2020 ◽  
Author(s):  
Claudio M. Verdun ◽  
Tim Fuchs ◽  
Pavol Harar ◽  
Dennis Elbrächter ◽  
David S. Fischer ◽  
...  
Keyword(s):  
Infection Rate ◽  
Web Application ◽  
Group Testing ◽  
Cross Sectional ◽  
Testing Procedures ◽  
Fine Grained ◽  
Testing Strategies ◽  
Care Workers ◽  
Efficiency Increase ◽  
Study Population

AbstractWe provide a comparison of general strategies for group testing in view of their application to medical diagnosis in the current COVID-19 pandemic. We find significant efficiency gaps between different group testing strategies in realistic scenarios for SARS-CoV-2 testing, highlighting the need for an informed decision of the pooling protocol depending on estimated prevalence, target specificity, and high- vs. low-risk population. For example, using one of the presented methods, all 1.47 million inhabitants of Munich, Germany, could be tested using only around 141 thousand tests if an infection rate up to 0.4% is assumed. Using 1 million tests, the 6.69 million inhabitants from the city of Rio de Janeiro, Brazil, could be tested as long as the infection rate does not exceed 1%. Altogether this work may help provide a basis for efficient upscaling of current testing procedures, fine grained towards the desired study population, e.g. cross-sectional versus health-care workers and adapted mixtures thereof. For comparative visualization and querying of the precomputed results we provide an interactive web application. The source code for computation is open and freely available.

The Advantages of Cryotechniques: Application To Bioluminescent Cells

1990 ◽  
Vol 48 (1) ◽  
pp. 486-487
Author(s):  
Gisèle Nicolas ◽  
Jean-Marie Bassot ◽  
Marie-Thérèse Nicolas
Keyword(s):  
Endoplasmic Reticulum ◽  
Striated Muscle ◽  
Light Emission ◽  
Stable State ◽  
Freeze Substitution ◽  
Initial Step ◽  
Point Of Interest ◽  
Cell Components ◽  
Excellent Preservation ◽  
External Water

The use of fast-freeze fixation (FFF) followed by freeze-substitution (FS) brings substantial advantages which are due to the extreme rapidity of this fixation compared to the conventional one. The initial step, FFF, physically immobilizes most molecules and therefore arrests the biological reactions in a matter of milliseconds. The second step, FS, slowly removes the water content still in solid state and, at the same time, chemically fixes the other cell components in absence of external water. This procedure results in an excellent preservation of the ultrastructure, avoids osmotic artifacts,maintains in situ most soluble substances and keeps up a number of cell activities including antigenicities. Another point of interest is that the rapidity of the initial immobilization enables the capture of unstable structures which, otherwise, would slip towards a more stable state. When combined with electrophysiology, this technique arrests the ultrastructural modifications at a well defined state, allowing a precise timing of the events.We studied the epithelium of the elytra of the scale-worm, Harmothoe lunulata which has excitable, conductible and bioluminescent properties. The intracellular sites of the light emission are paracrystals of endoplasmic reticulum (PER), named photosomes (Fig.1). They are able to flash only when they are coupled with plasma membrane infoldings by dyadic or triadic junctions (Fig.2) basically similar to those of the striated muscle fibers. We have studied them before, during and after stimulation. FFF-FS showed that these complexes are labile structures able to diffentiate and dedifferentiate within milliseconds. Moreover, a transient network of endoplasmic reticulum was captured which we have named intermediate endoplasmic reticulum (IER) surrounding the PER (Fig.1). Numerous gap junctions are found in the membranous infoldings of the junctional complexes (Fig.3). When cryofractured, they cleave unusually (Fig.4-5). It is tempting to suggest that they play an important role in the conduction of the excitation.

Physical Illness and Suicide Risk in Rural Residents of Contemporary China

Crisis ◽  
2014 ◽  
Vol 35 (5) ◽  
pp. 330-337 ◽  
Author(s):  
Cun-Xian Jia ◽  
Lin-Lin Wang ◽  
Ai-Qiang Xu ◽  
Ai-Ying Dai ◽  
Ping Qin
Keyword(s):  
Risk Factor ◽  
Family Income ◽  
Rural China ◽  
Significant Risk ◽  
Significant Risk Factor ◽  
Health Condition ◽  
Physical Illness ◽  
Rural Residents ◽  
Increased Risk ◽  
Study Population

Background: Physical illness is linked with an increased risk of suicide; however, evidence from China is limited. Aims: To assess the influence of physical illness on risk of suicide among rural residents of China, and to examine the differences in the characteristics of people completing suicide with physical illness from those without physical illness. Method: In all, 200 suicide cases and 200 control subjects, 1:1 pair-matched on sex and age, were included from 25 townships of three randomly selected counties in Shandong Province, China. One informant for each suicide or control subject was interviewed to collect data on the physical health condition and psychological and sociodemographic status. Results: The prevalence of physical illness in suicide cases (63.0%) was significantly higher than that in paired controls (41.0%; χ2 = 19.39, p < .001). Compared with suicide cases without physical illness, people who were physically ill and completed suicide were generally older, less educated, had lower family income, and reported a mental disorder less often. Physical illness denoted a significant risk factor for suicide with an associated odds ratio of 3.23 (95% CI: 1.85–5.62) after adjusted for important covariates. The elevated risk of suicide increased progressively with the number of comorbid illnesses. Cancer, stroke, and a group of illnesses comprising dementia, hemiplegia, and encephalatrophy had a particularly strong effect among the commonly reported diagnoses in this study population. Conclusion: Physical illness is an important risk factor for suicide in rural residents of China. Efforts for suicide prevention are needed and should be integrated with national strategies of health care in rural China.

Sign in / Sign up

Export Citation Format

Share Document