scholarly journals Beating your Neighbor to the Berry Patch

2020 ◽  
Author(s):  
Alan R. Rogers
Keyword(s):  
Nash Equilibrium ◽  
Mixed Strategy ◽  
Human Subjects ◽  
Pure Strategy ◽  
Initial Period ◽  
Mean Value ◽  
Mixed Strategies ◽  
The Mean ◽  
The Cost ◽  
Evolutionarily Stable

AbstractThis paper studies the situation in which multiple foragers compete for a resource that ripens (or otherwise improves) gradually. There is a unique mixed Nash Equilibrium (NE), which is stable against pure-strategy invaders provided that either the cost of visiting the resource or number of competitors is large. This equilibrium is not evolutionarily stable, however, because mixed strategies that are similar to the NE can invade.This mixed-strategy instability was not observed in computer simulations. The process converged to the neighborhood of the NE whenever the parameters implied stablity against pure-strategy invaders. Experiments with human subjects also failed to exhibit this mixed-strategy instability. After an initial period of familiarization, the behavior of human subjects was close to that predicted by the NE.This suggests that the NE may be useful as a prediction of behavior, and when that it true, strange conclusions emerge: the larger the number of foragers, the less likely it is that the resource will be harvested at all, and the greater the mean value of that resource when it is harvested.

On the Foundations of Nash Equilibrium

1996 ◽  
Vol 12 (1) ◽  
pp. 67-88 ◽  
Author(s):  
Hans Jørgen Jacobsen
Keyword(s):  
Game Theory ◽  
Nash Equilibrium ◽  
Cooperative Game Theory ◽  
Mixed Strategy ◽  
Pure Strategy ◽  
Mixed Strategies ◽  
Positive Theory ◽  
Equilibrium Concept ◽  
Strategy Equilibrium ◽  
Pure Strategies

The most important analytical tool in non-cooperative game theory is the concept of a Nash equilibrium, which is a collection of possibly mixed strategies, one for each player, with the property that each player's strategy is a best reply to the strategies of the other players. If we do not go into normative game theory, which concerns itself with the recommendation of strategies, and focus instead entirely on the positive theory of prediction, two alternative interpretations of the Nash equilibrium concept are predominantly available.In the more traditional one, a Nash equilibrium is a prediction of actual play. A game may not have a Nash equilibrium in pure strategies, and a mixed strategy equilibrium may be difficult to incorporate into this interpretation if it involves the idea of actual randomization over equally good pure strategies. In another interpretation originating from Harsanyi (1973a), see also Rubinstein (1991), and Aumann and Brandenburger (1991), a Nash equilibrium is a ‘consistent’ collection of probabilistic expectations, conjectures, on the players. It is consistent in the sense that for each player each pure strategy, which has positive probability according to the conjecture about that player, is indeed a best reply to the conjectures about others.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski
Keyword(s):  
Human Subjects ◽  
Coronary Thrombosis ◽  
Mean Value ◽  
Healthy Human ◽  
Protamine Sulphate ◽  
Soluble Fibrin ◽  
Fibrin Monomer ◽  
Dog Plasma ◽  
The Mean ◽  
Precipitable Protein

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

scholarly journals Anticoagulation in Cardiopulmonary Bypass

1977 ◽  
Author(s):  
C. Thomas Kisker ◽  
John A. Young ◽  
Donald B. Doty ◽  
Barbara J. Taylor
Keyword(s):  
Cardiopulmonary Bypass ◽  
Antithrombin Iii ◽  
Human Subjects ◽  
Mean Value ◽  
Clotting Time ◽  
Excessive Bleeding ◽  
Safe Level ◽  
Activated Clotting Time ◽  
Before And After ◽  
The Mean

Prolonging the activated clotting time (ACT) 2 to 3 times normal is said to provide a “safe” level of anticoagulation during cardiopulmonary bypass. To test this level of anticoagulation 9 monkeys were anticoagulated with heparin at the start of cardiopulmonary bypass so that ACT’s ranged from 201 sec to > 1000 sec (normal 91 sec). ACT, platelet count (P), fibrinogen (F), and fibrin monomer (FM) were measured at 10, 30, 60, 90, and 120 minutes during bypass. Antithrombin III (AT3) was measured before and after bypass. Six monkeys developed increased FM indicating active coagulation beginning from 10 to 60 minutes on bypass. ACT’s were > 200 sec in all animals at the time of FM detection. P fell below 100,000/mm3 in the 6 animals with elevated FM, but remained above 100,000/mm3 in the other 3 animals. The mean value of AT3 (69%) decreased to 24.4% after bypass in the 6 animals with elevated FM, but was 61% after bypass in the others. Scanning electron microscopy of the oxygenator membranes showed significant amounts of fibrin on the membranes used in monkeys who developed increased FM levels, but not on those with normal FM concentrations. F decreased from 167 mgm/dl to 80.5 mgm/dl in monkeys with elevated FM and to 117 mgm/dl in those with normal FM concentrations. Excessive bleeding did not occur in the animals without increased FM although ACT’s were in excess of 1000 sec. Subsequently three human subjects on cardiopulmonary bypass whose ACT’s were maintained above 400 sec have not shown increased FM levels. The results suggest that prolonging the ACT more than 2 - 3 times normal is required to prevent activation of clotting during cardiopulmonary bypass.

scholarly journals Epidemiological Comparison between Microsurgery and Embolization of Aneurysms in Brazil from 2010 to 2015

2018 ◽  
Vol 27 (2) ◽  
pp. 168-174
Author(s):  
Matheus De Andrade Bannach ◽  
Mariana Lima Caetano ◽  
Caio Átila Saloio ◽  
José Édison Da Silva Cavalcante ◽  
Helioenai De Sousa Alencar
Keyword(s):  
Health Information System ◽  
Mean Value ◽  
Morbidity And Mortality ◽  
Endovascular Coiling ◽  
P Value ◽  
International Literature ◽  
Surgical Clipping ◽  
The Mean ◽  
Using Data ◽  
The Cost

Introduction: Intracerebral Aneurysms are important causes of morbidity and mortality, with mortality rate of up to 50%. Endovascular coiling was introduced as an alternative to surgical clipping, and has shown better results with a reduction in morbidity and mortality risk of 6-9%. Objective: To characterize the two types of treatment for intracerebral aneurysms within Brazilian scenario, and to compare the results with the international literature. Methods: An analytic observational study using data from the SIH / DATASUS (National Health Information System) in the period of 2010-2015. Results: The total number of hospitalizations decreased, with a 38.3% decrease in clipping and 18.4% in embolizations. The mean value of embolization was significantly higher, however, presenting a downward trend (R$ 22,011.37 in 2010 to R$ 15,607.18 in 2015), while the value of microsurgery increased (R$ 7,022.31 to R$ 8,645.28, respectively). Microsurgery was a risk factor for death (p-value <0.01). Conclusion: It has been shown that the international trend of transition from clipping to embolization did not occur in Brazil. The cost of embolization is much higher. For the authors, the death outcome contrasts with literature due to confounding factors that act within limitations of the study.

Respiratory quotients of human kidney in vivo

1963 ◽  
Vol 18 (4) ◽  
pp. 815-817 ◽  
Author(s):  
Earl S. Barker ◽  
Archer P. Crosley ◽  
John K. Clark
Keyword(s):  
Human Subjects ◽  
Human Kidney ◽  
Mean Value ◽  
Whole Body ◽  
Mean Values ◽  
Anesthetized Dogs ◽  
The Mean ◽  
Urine Formation ◽  
Analytical Errors

Renal respiratory quotient (RQ) has been calculated from data collected in unanesthetized human subjects. In contrast to RQ recently reported on anesthetized dogs, these data do not indicate a mean value greater than 1. Under control conditions in 24 subjects, renal RQ calculated without special corrections averaged 0.88. Correcting for differences in blood flow between renal artery and vein due to urine formation the mean was 0.73, with 95% confidence limits 0.49–0.97. With alkaline urines an additional correction for urinary excretion of CO2 is advised. Excluding procedures known to alkalinize the urine, RQ values were similar in 46 observations after a variety of experimental procedures. Since both numerator and denominator of the ratio involve small differences between large values, small analytical errors can produce large changes indistinguishable from physiologic variation. Therefore mean values rather than individual observations are stressed. While such values in our data appear similar to RQ for other organs and the whole body, they do not preclude considerable anaerobic metabolism. Submitted on August 9, 1962

Attitude and Practice Towards Aflatoxin Contamination in Food and Sociodemographic Factors Contributed Toward Urinary AFM1 Occurrence Among Residents in Hulu Langat, Selangor, Malaysia

2020 ◽  
Author(s):  
Siti Husna Sulaiman ◽  
Wei Lin Chang ◽  
Rosita Jamaluddin ◽  
Mohd Redzwan Sabran
Keyword(s):  
Household Income ◽  
Human Subjects ◽  
Sociodemographic Factors ◽  
Cross Sectional Study ◽  
Mean Value ◽  
Aflatoxin Contamination ◽  
Cross Sectional ◽  
Monthly Household Income ◽  
Attitude And Practice ◽  
The Mean

Abstract Background: Aflatoxin occurrence could be affected by several factors. This study aimed to assess the association between knowledge, attitude and practice (KAP) towards aflatoxin and sociodemographic factors with urinary AFM1 occurrence among residents in Hulu Langat, Selangor. Methods: A cross-sectional study was conducted among healthy Malaysian adults aged 18 to 60 years in six subdistricts of Hulu Langat, Selangor. Sociodemographic factors and KAP towards aflatoxin were assessed via questionnaires while morning urine sample was collected for AFM 1 analysis. Of 444 respondents, the urinary AFM 1 level was detected in 199 samples (detection rate = 44.8 %). From 37 positive samples with AFM 1 level above the detection limit of 0.64 ng/ml, the mean value was 1.23 ± 0.91 ng/ml with a range of 0.65 – 5.34 ng/ml (median = 0.89 ng/ml). The variables were examined based on the occurrence of urinary AFM 1 biomarker. Results: Findings showed that there were significant differences in urinary AFM1 occurrence across ethnicity ( p <0.01), age group ( p <0.05), monthly household income ( p <0.01), as well as attitude ( p <0.01) and practice ( p <0.05) towards aflatoxin contamination in food. Binomial logistic regression confirmed that ethnicity and monthly household income were the factors contributing to urinary aflatoxin occurrence ( p <0.01). Chinese were 3.20 times more likely to have aflatoxin exposure than the non-Chinese. Detected urinary AFM 1 was more common among household with income more than RM 1500 monthly. Conclusion: The results provided an insight to explain the variation in aflatoxin occurrence among the population. Trial registration: Ethics Committee for Research Involving Human Subjects Universiti Putra Malaysia (JKEUPM), project number: FPSK (EXP16) P047

scholarly journals Cooperation in the Prisoner’s Dilemma: an experimental comparison between pure and mixed strategies

2019 ◽  
Vol 6 (7) ◽  
pp. 182142
Author(s):  
Leonie Heuer ◽  
Andreas Orland
Keyword(s):  
Treatment Group ◽  
Prisoner's Dilemma ◽  
Mixed Strategy ◽  
Pure Strategy ◽  
Prisoner’S Dilemma ◽  
Experimental Comparison ◽  
Control Group ◽  
Strategy Group ◽  
Mixed Strategies ◽  
Pure Strategies

Cooperation is—despite not being predicted by game theory—a widely documented aspect of human behaviour in Prisoner’s Dilemma (PD) situations. This article presents a comparison between subjects restricted to playing pure strategies and subjects allowed to play mixed strategies in a one-shot symmetric PD laboratory experiment. Subjects interact with 10 other subjects and take their decisions all at once. Because subjects in the mixed-strategy treatment group are allowed to condition their level of cooperation more precisely on their beliefs about their counterparts’ level of cooperation, we predicted the cooperation rate in the mixed-strategy treatment group to be higher than in the pure-strategy control group. The results of our experiment reject our prediction: even after controlling for beliefs about the other subjects’ level of cooperation, we find that cooperation in the mixed-strategy group is lower than in the pure-strategy group. We also find, however, that subjects in the mixed-strategy group condition their cooperative behaviour more closely on their beliefs than in the pure-strategy group. In the mixed-strategy group, most subjects choose intermediate levels of cooperation.

scholarly journals A HIDDEN MARKOV MODEL FOR THE DETECTION OF PURE AND MIXED STRATEGY PLAY IN GAMES

2014 ◽  
Vol 31 (4) ◽  
pp. 729-752 ◽  
Author(s):  
Jason Shachat ◽  
J. Todd Swarthout ◽  
Lijia Wei
Keyword(s):  
Markov Model ◽  
Hidden Markov Model ◽  
Repeated Games ◽  
Mixed Strategy ◽  
Hidden Markov ◽  
Human Subjects ◽  
Mixed Strategies ◽  
Mixed Strategy Nash Equilibrium ◽  
Equilibrium Profile ◽  
Nonstationary Dynamics

We propose a statistical model to assess whether individuals strategically use mixed strategies in repeated games. We formulate a hidden Markov model in which the latent state space contains both pure and mixed strategies. We apply the model to data from an experiment in which human subjects repeatedly play a normal form game against a computer that always follows its part of the unique mixed strategy Nash equilibrium profile. Estimated results show significant mixed strategy play and nonstationary dynamics. We also explore the ability of the model to forecast action choice.

scholarly journals A Mixed Cooperative Dual to the Nash Equilibrium

Game Theory ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
H. W. Corley
Keyword(s):  
Nash Equilibrium ◽  
Mixed Strategy ◽  
The Other ◽  
Mixed Strategies ◽  
Mutual Support ◽  
Equilibrium Models ◽  
Expected Payoff ◽  
Berge Equilibrium

A mixed dual to the Nash equilibrium is defined for n-person games in strategic form. In a Nash equilibrium every player’s mixed strategy maximizes his own expected payoff for the other n-1 players’ strategies. Conversely, in the dual equilibrium every n-1 players have mixed strategies that maximize the remaining player’s expected payoff. Hence this dual equilibrium models mutual support and cooperation to extend the Berge equilibrium from pure to mixed strategies. This dual equilibrium is compared and related to the mixed Nash equilibrium, and both topological and algebraic conditions are given for the existence of the dual. Computational issues are discussed, and it is shown that for each n>2 there exists a game for which no dual equilibrium exists.

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