Reinforcement learning accounts for moody conditional cooperation behavior:experimental results

In social dilemma games, human participants often show conditional cooperation (CC) behavior or its variant called moody conditional cooperation (MCC), with which they basically tend to cooperate when many other peers have previously cooperated. Recent computational studies showed that CC and MCC behavioral patterns could be explained by reinforcement learning. In the present study, we use a repeated multiplayer prisoner’s dilemma game and the repeated public goods game played by human participants to examine whether MCC is observed across different types of game and the possibility that reinforcement learning explains observed behavior. We observed MCC behavior in both games, but the MCC that we observed was different from that observed in the past experiments. In the present study, whether or not a focal participant cooperated previously affected the overall level of cooperation, instead of changing the tendency of cooperation in response to cooperation of other participants in the previous time step. We found that, across different conditions, reinforcement learning models were approximately as accurate as a MCC model in describing the experimental results. Consistent with the previous computational studies, the present results suggest that reinforcement learning may be a major proximate mechanism governing MCC behavior

Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography ST segment elevation in lead aVR with less ST segment elevation in lead V1

AbstractOBJECTIVESWe sought to determine the electrocardiographic (ECG) features associated with acute left main coronary artery (LMCA) obstruction.BACKGROUNDPrediction of LMCA obstruction is important with regard to selecting the appropriate treatment strategy, because acute LMCA obstruction usually causes severe hemodynamic deterioration, resulting in a less favorable prognosis.METHODSWe studied the admission 12-lead ECGs in 16 consecutive patients with acute LMCA obstruction (LMCA group), 46 patients with acute left anterior descending coronary artery (LAD) obstruction (LAD group) and 24 patients with acute right coronary artery (RCA) obstruction (RCA group).RESULTSLead aVR ST segment elevation (>0.05 mV) occurred with a significantly higher incidence in the LMCA group (88% [14/16]) than in the LAD (43% [20/46]) or RCA (8% [2/24]) groups. Lead aVR ST segment elevation was significantly higher in the LMCA group (0.16 ± 0.13 mV) than in the LAD group (0.04 ± 0.10 mV). Lead V1ST segment elevation was lower in the LMCA group (0.00 ± 0.21 mV) than in the LAD group (0.14 ± 0.11 mV). The finding of lead aVR ST segment elevation greater than or equal to lead V1ST segment elevation distinguished the LMCA group from the LAD group, with 81% sensitivity, 80% specificity and 81% accuracy. A ST segment shift in lead aVR and the inferior leads distinguished the LMCA group from the RCA group. In acute LMCA obstruction, death occurred more frequently in patients with higher ST segment elevation in lead aVR than in those with less severe elevation.CONCLUSIONSLead aVR ST segment elevation with less ST segment elevation in lead V1is an important predictor of acute LMCA obstruction. In acute LMCA obstruction, lead aVR ST segment elevation also contributes to predicting a patient’s clinical outcome

Factors influencing acute high-grade restenosis in emergency percutaneous transluminal coronary angioplasty for acute myocardial infarction.

We studied the factors which may induce acute high grade restenosis in emergency percutaneous transluminal coronary angioplasty (PTCA). PTCA was attempted in 50 patients with acute myocardial infarction, and the balloon catheter passed successfully across the occlusion site in 47 (94%) of the patients. These 47 patients were analyzed. &#34;Acute restenosis&#34; was defined as a lesion which was revascularized to less than 50% luminal reduction narrowed again to more than 75% luminal reduction 5 min after the balloon inflation. Univariate and multivariate analyses were used for determining factors which significantly influenced acute restenosis. The incidence of at least one restenosis episode was 45%. Multiple regression analysis selected 5 factors associated significantly with an increased rate of acute restenosis: 1) angiographic evidence of dissection, 2) lesion in the right coronary artery (RCA), 3) lack of or insufficient administration of thrombolytic agent preceding PTCA, 4) curved lesion and 5) relatively small balloon/artery diameter ratio. Acute restenosis correlated significantly with late reocclusion. This study indicates that it is important to administer a thrombolytic agent prior to emergency PTCA, and to use an adequately sized balloon to the artery when the acute restenosis occurs by using relatively smaller sized balloon. The present data also demonstrated that patients with RCA and a curved lesion have a relatively high risk of acute restenosis. This study indicates how patients with relatively high risk of acute restenosis may be identified.</p

Experimental studies on the effects of variable antero-posterior distance of the trunk upon ECG and VCG with torso models

The effects of variable antero-posterior distance of the trunk upon standard 12 lead systems and three different corrected orthogonal VCG lead systems were investigated with the reference to the lead vector. Human torso model of an average Japanese adult male and four elliptical cylinders, which had fixed height and left to right distance and variable antero-posterior distance were employed as a homogeneous volume conductor. Lead vectors were measured when the artificial current dipole was placed at each of 15 points in the heart area. The following results were made in the present study. 1) The presence of proximity effect in V1, V2, V3 and V4 leads were demonstrated. These proximity effects were greater value in the models with short antero-posterior distance of the trunk. 2) The normality and orthogonality of the Frank lead system were better than those of the modified Frank lead system in the models with long antero-posterior distance of the trunk. 3) The normality and orthogonality of the modified Frank lead system were better than those of the Frank lead system in the models with relatively short antero-posterior distance of the trunk. 4) The Mc Fee lead system had better orthogonality and worse normality. 5) The effects of variable dipole locations upon the lead vectors measured with each lead systems became considerably greater, according as the shortening of the antero-posterior distance of the trunk

An Interesting Case of Type A Wolff-Parkinson-White Syndrome

A case of Wolff-Parkinson-White syndrome who presented with a tachycardia showing an unusual QRS morphology closely resembling that of a ventricular tachycardia was reported. It showed type A or type B conduction of the Wolff-Parkinson-White syndrome in electrocardiogram in different time, but vectorcardiogram showed always type A conduction. After combinated administration of Quinidine and Reserpine, ECG reversed constantly to normal sinus rhythm

Commitment-enhancing tools in Centipede games: Evidencing European–Japanese differences in trust and cooperation

Theories of trust distinguish general trust in situations of social uncertainty from assurance-based trust in committed, long-term relationships. This study investigates European-Japanese differences using the Centipede game, in which two players choose between cooperation and defection. The game models repeated reciprocal interactions, necessitating assurance-based trust to sustain cooperation. We included game conditions offering players the option of purchasing commitment-enhancing tools to increase social certainty. Japanese participants were more cooperative than Europeans, confirming higher assurance-based trust, and also purchased more commitment-enhancing tools, demonstrating their preferences for social certainty. Purchase of commitment-enhancing tools improved cooperativeness in both groups. However, if co-players refused tool purchase, the Japanese appeared to interpret this as non-cooperative intent and cooperativeness in the respective games decreased

Cooperation and Trust in Japanese and British Samples: Evidence from Incomplete Information Games

Most human relationships are characterized by reciprocal patterns of give-and-take that can be studied using a decision-making task called the Centipede game. The game involves 2 players alternating in choosing between cooperation and defection, with their choices affecting payoffs to themselves and the co-player. We compared trust and cooperation of Japanese and U.K. samples in the Centipede game. To increase the game’s applicability to real-life decision situations, we added 3 treatment conditions to manipulate payoff information. Our between-subjects design comprised the following 4 conditions: (a) full payoff information, (b) full payoff information framed as percentages, (c) partial payoff information with absolute (own payoff) information only, and (d) partial payoff information with relative information only. Comparing Japanese and U.K. students’ decisions, the Japanese cooperated significantly more frequently than the British. The manipulation of payoff information also affected decision making. In Japan, both treatment conditions with incomplete information yielded significantly higher cooperation levels than the control. In the U.K., only the condition with absolute payoff information produced significantly higher cooperativeness. Overall, these findings suggest that Japanese samples cooperate more frequently in repeated interactions than British samples and that this may be due to the assurance-based trust elicited by reciprocal relationships that has been identified as a typical feature of Japanese culture. In situations with incomplete information, expectations about the stake size may guide decision making, with lower expectations resulting in higher cooperation levels

Echocardiographic study of school children

We studied the echocardiograms of 243 school children who needed further examination of the heart beyond electrocardiography, auscultation, chest X-ray and/or medical history. 1. Thirty of them showed mitral valve prolapse including two with Marfan's syndrome, one with arrythmias exaggerated by physical exercise and a case with left ventricular volume overloading. 2. Five of eight patients who were suspected to suffer from a atrial septal defect by electrocardiography and auscultation showed right ventricular volume overload echocardiographically. In four of the five, an intracardiac shunt at the atrial level was confirmed by contrast echocardiography. 3. One case with right ventricular hypertrophy as determined by electrocardiography showed right ventricular pressure stress echocardiographically. He was diagnosed as having primary pulmonary hypertension by cardiac catheterization. 4. A ventricular septal defect and patent ductus arteriosus were diagnosed in six cases by auscultation or phonocardiography, but not so by echocardiogaraphy. Echocardiography as a secondary examination is not only diagnostic in itself but also is beneficial in determining whether or not further examination (cardiac catheterization) is needed

Commitment-enhancing tools in centipede games: Evidencing European-Japanese differences in trust and cooperation

Theories of trust distinguish general trust in situations of social uncertainty from assurance-based trust in committed, long-term relationships. This study investigates European–Japanese differences using the Centipede game, in which two players choose between cooperation and defection. The game models repeated reciprocal interactions, necessitating assurance-based trust to sustain cooperation. We included game conditions offering players the option of purchasing commitment-enhancing tools to increase social certainty. Japanese participants were more cooperative than Europeans, confirming higher assurance-based trust, and also purchased more commitment-enhancing tools, demonstrating their preferences for social certainty. Purchase of commitment-enhancing tools improved cooperativeness in both groups. However, if co-players refused tool purchase, the Japanese appeared to interpret this as non-cooperative intent and cooperativeness in the respective games decreased